CN108872330A

CN108872330A - The evaluation method of heavy metal toxicity in a kind of Biological Nutrient Removal system

Info

Publication number: CN108872330A
Application number: CN201710339425.9A
Authority: CN
Inventors: 伍志趼; 张可方; 荣宏伟; 黄小鹏; 黄俊熙; 李伟斌; 张君贤; 洪涛; 邓超雄; 徐嘉琪; 曾伟强; 陈秋成; 唐永波; 黄卓贤
Original assignee: GUANGZHOU SEWAGE PURIFICATION Co Ltd
Current assignee: GUANGZHOU SEWAGE PURIFICATION Co Ltd
Priority date: 2017-05-15
Filing date: 2017-05-15
Publication date: 2018-11-23

Abstract

The present invention discloses a kind of evaluation method of heavy metal toxicity in Biological Nutrient Removal system, belongs to sewage treatment field.The method comprising the steps of：According to heavy metal to activated sludge INT-ETS activity, SOUR, AUR toxic effect evaluation index sensitivity level, sludge AUR activity is selected as bioactivity toxic effect evaluation index；Heavy metal toxicity is characterized according to the size of sludge AUR maximum inhibition % influences grade.The present invention furthers investigate influence of four heavy metal species common in sewage to sewage biological treatment system, inquires into the toxicity strong or weak relation between variety classes, and establishing characterization heavy metal toxicity influences the evaluation index of grade, quickly and effectively evaluates microbial activity.It theoretical foundation is provided establishes solid foundation for the normal operation of biological treatment.

Description

The evaluation method of heavy metal toxicity in a kind of Biological Nutrient Removal system

Technical field

The invention belongs to sewage treatment field, in particular to heavy metal poison in a kind of Biological Nutrient Removal system The evaluation method of property.

Background technique

Currently, the index for measuring active biomass in mixed liquor in sewage treatment is main or solid suspension concentration or waves Hair property solid suspension concentration, so that the operation control for sewage plant provides reference.But it is found in practical study and application, this Two indices not only cannot accurately indicate the true biomass and its activity of accepting/ordering system, but also there is another Important drawback, i.e., they can only reflect the big and heavy of cell, can not characterize microbial cell activity and distinguish activated sludge Difference between middle living cells, dead cell and inanimate volatile solids.

According to the toxicity mechanism of heavy metal, people once attempt to utilize DNA (DNA) or rna content (RNA), active bacteria number (ABN), atriphos (ATP) and synchronous scanning fluorescence method (Synchronous-scan The methods of) fluorometry or index quantifies the activity or active biomass of sludge in sewage disposal system.But DNA and RNA Measuring method is too cumbersome, needs instrument and the professional technician at high tip, time-consuming and long, and not only living cells contains, Dead cell also contains part DNA and RNA；ATP can reflect out the content of active biomass in activated sludge, but measuring method Triviality and complexity limit always it and further apply；Synchronous scanning fluorescence method can be efficiently used for assessment thallus to a huge sum of money The sensibility of category, but its method is equally too cumbersome, and the valuableness of instrument, and needs professional technician.According to a huge sum of money Belong to influence Microorganism respiration mechanism, at present sewage biological treatment system microorganism electron transport system (ETS, Electron Transport System) activity, than oxygen uptake rate (SOUR, Specific Oxygen Uptake Rate) And ammonia uptake rate (AUR) is the index quite paid attention in recent years by domestic and international relevant expert.

(1) electron transfer process and electron transport chain of microorganism

In the respiratory of microorganism, oxidation operation decomposition is formed by reduced coenzyme, including NADH and FADH2 will keep it reoxidized again by electron transport route.In this process, the hydrogen on reduced coenzyme is with proton shape Formula is taken off, and electronics is shifted along a series of electron transit mediator, and being finally transferred to final electron acceptor, (aerobic respiration is O₂；Anaerobic respiration is NO₃ ^-, SO₄ ^2-And CO₃ ^2-Deng).

Reduced coenzyme is reoxidized by electron transmission, this process is known as electron transfer process.Electron transfer process packet Include what electronics was made up of from reduced coenzyme a series of tactic electron transit mediators being incremented by according to electron affinity Electron transport chain is transmitted to the process of final electron acceptor, these electron transit mediators are all that there is the electronics of redox to carry Body.Electron transfer process is typically all mutually to be coupled with the formation of ATP, this mechanism is known as oxidative phosphorylation.Aoxidize phosphoric acid Change effect is electronics adjoint overall process that ADP phosphorylation is formed to ATP in along electron transport chain transmittance process.This A overall process is also known as oxidation-respiration chain or respiratory metabolism.

Currently, component found in electron transport chain oneself have 15 kinds or more.

(2) electron transport system (ETS) Activity determination principle

Measurement ETS activity is exactly to pass through that certain oxidation-reduction potential is added in culture medium than natural final electron acceptor Low artificial electron's receptor (also referred to as artificial hydrogen acceptor), is allowed to connect from electron transport chain before natural final electron acceptor By electronics.The variation of color can occur after being reduced in the cell for the artificial electron acceptor, pass through the artificial electricity after detection reduction The color change of sub- receptor can judge that respiratory chain transmits H⁺The rate and intensity of/e, and microorganism ETS can be quantified according to this Activity.Currently, the common artificial electron's receptor of microorganism ETS activity mainly has 2,3,5- chlorinations three in detection activated Sludge System Phenyl tetrazole (TTC) and iodine nitro tetrazole (INT).

TTC is that (also referred to as TTC- is de- for detecting sludge ETS activity for one kind of current field of biological sewage treatment most study Hydrogenase activity) electron acceptor.The oxidation-reduction potential of TTC is+460mV.In the measurement of TTC- dehydrogenase activity, using point Optical density caused by light photometric determination red TF can quantify TTC- dehydrogenase activity.

INT is also one of the most commonly used dehydrogenase activity detection agent (also referred to as INT- dehydrogenase activity), reduction process The oxidation-reduction potential of middle INT is that+90mV utilizes spectrophotometric determination purple in the measurement of INT- dehydrogenase activity Optical density caused by INTF can quantify INT- dehydrogenase activity.

The oxidation-reduction potential of TTC is higher, small to the affinity of electronics, weak with the ability of oxygen competition electronics.It is big both at home and abroad More scholars think, need to include oxygen scavenging step, the interference to avoid oxygen to experimental result when detecting sludge ETS activity with TTC. In addition, TTC is also not suitable for the bioactivity of detection anaerobism and denitrification denitrogenation sludge.Compared with TTC, the redox electricity of INT Position is lower, big to the affinity of electronics, and strong with the ability of oxygen competition electronics, experiment can carry out under aerobic conditions, can be used for examining Survey the bioactivity of aerobic, anaerobism and denitrifying sludge.

(3) the active principle of SOUR and AUR

The test philosophy of SOUR and the active measuring principle of ETS are inherently identical, the means only used and side Method is different.SOUR is the electron acceptor (O by measuring aerobic microbiological respiratory chain least significant end in closed container₂) consumption speed Rate, to judge degradation (de- electronics) rate of the delivery rate of electronics and organic substrates in microbial respiratory chain.The dirt of early stage Mud microorganism SOUR is usually to be measured by Wadi sheep.The working principle of Wadi sheep is:It is stirred continuously in constant temperature Under conditions of, so that a certain amount of microorganism and substrate is carried out haptoreaction in the reactor of constant volume, microorganism is in metabolic process In constantly consume dissolved oxygen, while releasing CO₂.Utilization and the CO of oxygen are measured on the manometer being connected with reactor₂Release institute Caused by net pressure change.If centre fills the cuvette of KOH, CO in the reactor₂It can all be absorbed.Pressure gauge institute at this time Caused by the pressure change of reaction is entirely microorganism oxygen consumption.According to the partial pressure of oxygen, the oxygen amount of consumption can be calculated.Watt Bo Shi is exhaled Suction method is not comparatively laborious, easy to operate.It, at present can be fast with simple dissolved oxygen electrode method with the rapid exploitation of dissolved oxygen electrode The SOUR of speed measurement microorganism.AUR is identical with SOUR measurement method, carries out the online of ammonia nitrogen again by dissolution ammonia nitrogen electrode Detection quickly measures the AUR of microorganism.

(4) ETS activity, SOUR, AUR measurement method application

Sludge ETS activity carrys out the breathing of indirect indicator microoraganism essentially by the electron transport rate of measurement microorganism Activity, and then carry out the bioactivity of qualitative activity sludge.The sample size that this method can detect simultaneously is unrestricted, operation letter Just, it is suitable for field application, required instrument and equipment is laboratory conventional instrument.SOUR is then by directly measuring microorganism Respiratory rate determines the metabolic rate of sludge aerobic microorganism.SOUR detection process is simple, is not necessarily to additional any reagent.AUR It is similar with SOUR activity test method, but its testing goal is different, it as a result may also be different.Such as in Cd²⁺、Cu²⁺And Pb²⁺Environment Middle ammonia uptake rate value is higher than oxygen uptake rate value, it is shown that these heavy metals are compared with heterotroph, are had to nitrobacteria lower Sensibility.Sludge ETS activity, SOUR and AUR both can reflect processing system microbial degradation organic substance from biology angle Ability, and can from the height of bioactivity measure organic matter degradation speed and biological treatment facility operational effect, thus As analysis, evaluation and the important indicator for predicting Sewage Biological Treatment ability.Active according to the ETS of sewage biological treatment system, SOUR and AUR analysis judges the activity of microorganism in sewage disposal system as a result, can monitor on-line to biological treatment performance Then state adjusts operating parameter in the way of automatic or manual, biological processing unit is enable to operate in optimal state Point guarantees that effluent quality reaches design requirement.Therefore, research and application sludge ETS activity, SOUR and AUR detection technique, for Promote the development of dirty water living creature processing technique, strengthens and improve the operation control of sewage biological treatment system, have particularly significant Meaning.

In recent years, the country such as the U.S., Germany, Britain, Canada has carried out the toxicological evaluation research of industrial wastewater extensively Work.Wherein U.S.'s Aquatic Toxicity Test be used as work out water quality benchmark, industrial wastewater discharge supervision and management and Carry out the necessary biological study means of toxic pollutant overall control and sharing of load.And China GB8978-1996《Country is comprehensive Close discharge standard》It is main and prepared with reference to the relevant emission standards of the Systems in Certain Developed Countries such as America and Europe, and the standard pair The supervision and management of water environment pollution is based on Physico-chemical tests means.China in each correlation water standard and discharge standard, Only DB31/199-2009《Shanghai City integrated wastewater discharge standard》Have in the second pollutant emission limit one be about Fish acute toxicity index, other correlation toxicologic index are opposite to be lacked^[53]。

Luminescent bacteria method is current a kind of widely used Mixed bacteria method, and this method is that have by detection The luminous inhibiting rate that noxious material generates photogen judges the size of noxious material toxicity.Utilize the method, the U.S. MICROTOX and Chinese Academy of Sciences's Nanjing soil divide toxic grade.In addition, China pair《Water standard》With《Discharge mark It is quasi-》In the toxicity of each heavy metal in water standard limited value evaluated.As can be seen that heavy metal threshold value be largely in it is nontoxic or In the range of low toxicity, only the total copper in part and total zinc are in weight poison and altitude range.Allow heavy metals emission dense in highest In degree, total lead, total zinc and total copper are in height to the range of severe toxicity.Toxicity assessment result reflects China's water from a side The control of part heavy metal threshold value may be higher in body.

However, China makes specific division to the toxic grade standard of poisonous and harmful substance in water body at present not yet, Therefore formulating heavy metal toxicity classification standard using microbial activity index in the present invention is to have larger scientific progress meaning 's.

Summary of the invention

In order to overcome the disadvantages and deficiencies of the prior art, the purpose of the present invention is to provide a kind of municipal sewage biological denitrificaions The evaluation method of heavy metal toxicity in dephosphorization system.

The purpose of the invention is achieved by the following technical solution：

The evaluation method of heavy metal toxicity, includes the following steps in a kind of Biological Nutrient Removal system：

(1) according to heavy metal to activated sludge INT-ETS activity, SOUR, AUR toxic effect evaluation index sensitivity level, choosing Sludge AUR activity is determined as bioactivity toxic effect evaluation index；

(2) heavy metal toxicity is characterized according to the size of sludge AUR maximum inhibition % influences grade.

The evaluation criterion that the heavy metal toxicity influences grade is；

The heavy metal is copper (Cu²⁺), cadmium (Cd²⁺), zinc (Zn²⁺) and chromium (Cr⁶⁺At least one of)；

In the activated sludge, microorganism concn (MLSS) is preferably 2000~3000mg/L, and COD load is 200~ 400mg/L, dissolved oxygen (DO) are 0~1.5mg/L, pH=6~8.0.

Need to control effluent COD concentration within 50mg/L, NH₄ ⁺Within 8mg/L, this needs to remove sludge-N concentration Rate reaches 80% or more, therefore, with 80%NH₄ ⁺- N removal rate, COD removal rate define the nonpoisonous state of heavy metal toxicity.

Mechanism of the invention is：The present invention furthers investigate four heavy metal species common in sewage to sewage biological treatment system Influence, inquire into variety classes between toxicity strong or weak relation, establish characterization heavy metal toxicity influence grade evaluation index, fastly Fast effective evaluation microbial activity.It theoretical foundation is provided establishes solid foundation for the normal operation of biological treatment.

The present invention compared with the existing technology, has the following advantages and effect：

It uses simulated domestic wastewater for process object herein, is tested using the activated sludge tamed in laboratory, High spot reviews study influence and Analysis on Mechanism of the heavy metal to denitrification dephosphorization system microbial activity under varying environment factor, On this basis, sludge INT-ETS activity, sludge SOUR, sludge AUR, microbial activity inhibiting rate and EC50, system is introduced to examine Different heavy metals are examined under the conditions of various concentration to the affecting laws of sludge activity, judge heavy metal to the toxic effect of bioactivity The sensitivity of evaluation index is established the recovery Journal of Sex Research that toxicity assessment classification standard and microbial activity influence, while being carried out Wastewater toxicity cuts down the research of intensive treatment technology, obtains following Main Conclusions：

(1) microbial dehydrogenation enzymatic activity, SOUR and AUR can be obviously promoted by improving sludge concentration；Be conducive to microorganism resistance Heavy metal ion toxicity.Heavy metal copper cadmium exist in the case of, improve COD load may advantageously facilitate microbial dehydrogenation enzymatic activity and SOUR, but it is unfavorable for the existence of nitrobacteria；It is then opposite that zinc ion, which exists,.Heavy metal toxicity and pH, DO relationship have close pass System.The raising of DO and heavy metal toxicity generally play synergistic effect.For nitrobacteria, DO is averaged in 1.5mg/L or less, The increase of dissolved oxygen can be such that its AUR improves, but excessively high dissolved oxygen equally promotes cadmium ion and makees to the murder by poisoning of nitrobacteria With.

(2) after gradually increasing concentration of heavy metal ion, the activity of activated sludge shows gradually biological denitrification system Reduced trend, the sequence that 4 metal ion species influence sludge activity are：Cu²⁺> Cd²⁺> Zn²⁺> Gr⁶⁺。Cu²⁺System is taken off In the influence of nitrogen sludge activity, AUR activity can most reflect the suppressed effect of sludge activity；In Cd²⁺INT-ETS activity is most in research It can reflect Cd²⁺Influence to the sludge activity of sludge organism denitrification system；And in Zn²⁺And Gr⁶⁺In research, AUR activity most can be anti- Reflect the suppressed effect of sludge activity.The inhibition of 4 heavy metal species ion pair nitrification effects is all larger than the suppression of the decomposition to organic matter System；Compared with heterotroph, nitrobacteria is more sensitive to various heavy metal ion toxicity.

(3) it is obtained by the experimental study to dephosphorization system：Copper, cadmium, 3 heavy metal species ion concentration of zinc respectively 4mg/L, Start to significantly affect water outlet total phosphorus concentration generation when 20mg/L, 10mg/L or more；3 heavy metal species influence biological phosphor-removing effect Size order is：Cu²⁺> Zn²⁺> Cd²⁺；In anaerobism section：Under heavy metal ion inhibits, 3 heavy metal species are to anaerobic activated sludge The toxicity size order of INT-ETS activity suppression is：Cu²⁺> Zn²⁺> Cd²⁺；In aerobic section：3 heavy metal species are to INT-ETS The toxicity size order of activity suppression is respectively：Cu²⁺> Zn²⁺> Cd²⁺。

(4) 4 each activity index of heavy metal species ion pair denitrification system toxicity half-suppressed (toxicity half-suppressed：That is inhibiting rate etc. In 50% toxicity size, the smaller toxicity then half-suppressed of 503nhibiting concentration is bigger) it is sequentially different, INT-ETS and SOUR are living The sequence of property is：Cu²⁺> Cd²⁺> Zn²⁺> Cr⁶⁺；The active sequence of AUR is：Cu²⁺> Zn²⁺> Cd²⁺> Cr⁶⁺.By to each Metal ion EC50's is calculated：The evaluation index that AUR activity influences microbial activity toxic effect as characterization heavy metal It is the sensitiveest.

(5) the characterization heavy metal toxicity established influences grade evaluation criterion, is shown in Table 7.

(6) when microflora is destroyed by poisonous and harmful substances such as heavy metals, there is certain self-repairing capability, but The time of self-recovery is different, and this ability is effective in certain damage envelope, it is generally the case that heavy metal concentration Higher, the time required for self-regeneration is longer.As addition 1mg/L Cu in biological treatment system²⁺When, system self-regeneration institute The time needed is about 8 periods；As addition 5mg/L Cu in biological treatment system²⁺When, when required for system self-regeneration Between about 10 periods；As addition 10mg/L Cu in biological treatment system²⁺When, the time required for system self-regeneration is about 20 periods；As addition 25mg/L Cu in biological treatment system²⁺When, system is by more serious destruction, self-repairing capability Weaken and even disappears.

Detailed description of the invention

Fig. 1 is the relationship of INTF concentration Yu its absorbance.

Fig. 2 is Cu²⁺In the presence of, the relationship of sludge concentration and COD, ammonia nitrogen removal frank.

Fig. 3 is the Cu of 7.5mg/L in different sludge concentrations²⁺To the inhibition situation of sludge activity.

Fig. 4 is Cd²⁺In the presence of, the relationship of sludge concentration and COD, ammonia nitrogen removal frank.

Fig. 5 is the Cd of 20mg/L in different sludge concentrations²⁺To the inhibition situation of sludge activity.

Fig. 6 is Zn²⁺In the presence of, the relationship of sludge concentration and COD, ammonia nitrogen removal frank.

Fig. 7 is the Zn of 15mg/L in different sludge concentrations²⁺To the inhibition situation of sludge activity.

Fig. 8 is Cu²⁺In the presence of, the relationship of COD load and COD, ammonia nitrogen removal frank

Fig. 9 is the Cu in 7.5mg/L concentration²⁺In the case of inhibition, COD load influences microbial activity.

Figure 10 is Cd²⁺In the presence of, the relationship of COD load and COD, ammonia nitrogen removal frank.

Figure 11 is in 15mg/L concentration C d²⁺In the case of inhibition, COD load influences microbial activity.

Figure 12 is Zn²⁺In the presence of, the relationship of COD load and COD, ammonia nitrogen removal frank.

Figure 13 is in 15mg/L concentration Zn²⁺In the case of inhibition, COD load influences microbial activity.

Figure 14 is Cu²⁺In the presence of, the relationship of pH and COD, ammonia nitrogen removal frank.

Figure 15 is the Cu in 5mg/L concentration²⁺In the case of inhibition, influence of the pH to microbial activity.

Figure 16 is Cd²⁺In the presence of, the relationship of pH and COD, ammonia nitrogen removal frank.

Figure 17 is the Cd in 15mg/L concentration²⁺In the case of inhibition, influence of the pH to microbial activity.

Figure 18 is Zn²⁺In the presence of, the relationship of pH and COD, ammonia nitrogen removal frank.

Figure 19 is the Zn in 15mg/L concentration²⁺In the case of inhibition, influence of the pH to microbial activity.

Figure 20 is Cu²⁺In the presence of, the relationship of DO and COD, ammonia nitrogen removal frank.

Figure 21 is the Cu in 5mg/L concentration²⁺In the case of inhibition, DO influences microbial activity.

Figure 22 is Cd²⁺In the presence of, the relationship of DO and COD, ammonia nitrogen removal frank.

Figure 23 is the Cd in 15mg/L concentration²⁺In the case of inhibition, DO influences microbial activity.

Figure 24 is Zn²⁺In the presence of, the relationship of DO and COD, ammonia nitrogen removal frank.

Figure 25 is the Zn in 15mg/L concentration²⁺In the case of inhibition, DO influences microbial activity.

Figure 26 is Cu²⁺Concentration and the active relationship of ETS.

Figure 27 is Cu²⁺The relationship of concentration and SOUR, AUR.

Figure 28 is Cu²⁺Concentration and the active relationship of INT-ETS.

Figure 29 is Zn²⁺Concentration and the active relationship of ETS.

Figure 30 is Zn²⁺The relationship of concentration and SOUR, AUR.

Figure 31 is Zn²⁺Concentration and the active relationship of INT-ETS.

Figure 32 is Cd²⁺Concentration and the active relationship of ETS.

Figure 33 is Cd²⁺The relationship of concentration and SOUR, AUR.

Figure 34 is Cd²⁺Concentration and the active relationship of INT-ETS.

Figure 35 is Cr⁶⁺On the active influence of sludge INT-ETS.

Figure 36 is Cr⁶⁺Influence to sludge SOUR, AUR.

Figure 37 is Cu²⁺The relationship of concentration and INT, SOUR and AUR inhibiting rate.

Figure 38 is Zn²⁺The relationship of concentration and INT, SOUR and AUR inhibiting rate.

Figure 39 is Cd²⁺The relationship of concentration and INT, SOUR and AUR inhibiting rate.

Figure 40 is Cr⁶⁺The relationship of concentration and INT, SOUR and AUR inhibiting rate.

Figure 41 is that Cu is added in activated Sludge System²⁺Afterwards, AUR maximum inhibition and NH₄ ⁺Pass between-N removal rate System.

Figure 42 is that Cd is added in activated Sludge System²⁺Afterwards, AUR maximum inhibition and NH₄ ⁺Pass between-N removal rate System.

Figure 43 is that Zn is added in activated Sludge System²⁺Afterwards, AUR maximum inhibition and NH₄ ⁺Pass between-N removal rate System.

Figure 44 is that Cr is added in activated Sludge System⁶⁺Afterwards, AUR maximum inhibition and NH₄ ⁺Relationship between-N.

Figure 45 is 1mg/L Cu²⁺To NH₄ ⁺The influence of-N removal rate, COD removal rate.

Figure 46 is 1mg/L Cu²⁺On the active influence of INT-ETS.

Figure 47 is 1mg/L Cu²⁺On SOUR activity, the active influence of AUR.

Figure 48 is 5mg/L Cu²⁺To NH₄ ⁺The influence of-N removal rate, COD removal rate.

Figure 49 is 5mg/L Cu²⁺On the active influence of INT-ETS.

Figure 50 is 5mg/L Cu²⁺On SOUR activity, the active influence of AUR.

Figure 51 is 10mg/L Cu²⁺To NH₄ ⁺The influence of-N removal rate, COD removal rate.

Figure 52 is 10mg/L Cu²⁺On the active influence of INT-ETS.

Figure 53 is 10mg/L Cu²⁺On SOUR activity, the active influence of AUR.

Figure 54 is 25mg/L Cu²⁺To NH₄ ⁺The influence of-N removal rate, COD removal rate.

Figure 55 is 25mg/L Cu²⁺On the active influence of INT-ETS.

Figure 56 is 25mg/L Cu²⁺On SOUR activity, the active influence of AUR.

Specific embodiment

Present invention will now be described in further detail with reference to the embodiments and the accompanying drawings, but embodiments of the present invention are unlimited In this.

Research of the 1 ETS activity characterization heavy metal of embodiment to Ecotoxicology effect

1.1 heavy metals are to Ecotoxicology effect relevant measurement method

1.1.1 INT-ETS detection method

1.1.1.1 the drafting of INT-ETS standard curve

(1) main agents and preparation method

INT standard solution：0.2g INT (import packing) is weighed, is dissolved in a small amount of distilled water, 500mL brown appearance is settled to It in measuring bottle, is stored in dark brown volumetric flask, this solution is the INT standard solution of 0.4g/L.

Tris-HCl buffer solution (pH=8.6)：6.037g Tris (trishydroxymethylaminomethane is analyzed pure) is weighed, is added Enter 20mL 1.0mol/L HCl, then is settled to 1L.

Hydrogensulfite solution：1g sodium dithionite is weighed, is dissolved in a small amount of water, is settled in 100mL volumetric flask, Now match and first uses.

(2) drafting of standard curve

In 7 25mL colorimetric cylinders, the INT standard solution of different volumes is sequentially added, 2mL Tris-HCl buffer, INT standard solution is not added in 1mL hydrogensulfite solution, control tube, and after solution sufficiently develops the color, each pipe is separately added into 20mL first The INTF of alcohol, generation to be reacted is settled to scale with distilled water after completely dissolution, and absorbance value is measured at wavelength 485nm, with Reagent blank compares, and it is as shown in Figure 1 to draw standard curve.

1.1.1.2 the active analysis method of INT-ETS

Take 0.6mL mud mixed liquid, be placed in the centrifuge tube of 15mL, then thereto be added 3mL Tris-HCI buffering it is molten The 0.2%INT solution of liquid, 2mL.The sample prepared is placed on to rapidly shaken cultivation in the water bath chader of (37 ± 1) DEG C 30min, then plus 37% formaldehyde of 2mL is to terminate the reaction of enzyme.The sample is centrifuged 5min at 4000r/min, is gently abandoned Supernatant is removed, the methanol of 10mL is added, after being uniformly mixed, continues the dark place oscillation extraction 30min at (37 ± 1) DEG C.To Sample extraction finishes, and is centrifuged 5min again at 4000r/min, and supernatant and precipitating sludge are separated.Existed with spectrophotometer The absorbance of extract liquor is read at 485nm.The active calculation formula of INT-ETS is as follows：

In formula：UT --- INT-ETS activity [mg INTF/ (g TSSh)]；D₄₈₅--- the supernatant at wavelength 485nm Absorbance；V --- extractant volume (mL)；K --- slope of standard curve takes 0.0108 (L/mg)；W --- mud dry weight (mg)；T --- incubation time (h).

1.1.2SOUR detection method

Using the SOUR of dissolved oxygen electrode measurement activated sludge.Activated sludge sample is placed in conical flask first, sufficiently Aeration makes it dissolve oxygen concentration and reaches saturation state, is inserted into dissolved oxygen electrode, and record dissolved oxygen changes with time.It is surveying During examination, mud sample is mixed using magnetic stirring apparatus, and notices that the air-tightness of conical flask will be got well.Dissolution to be done After oxygen measurement, the activated sludge sample in SOUR bottles is all taken out and measures its sludge concentration.Utilize the straight line portion of DO-T curve Divide and sludge concentration calculates SOUR, calculation formula is as follows：

In formula：Ratio oxygen uptake rate (the mg O of Uo --- activated sludge₂/(g TSS·h)]；Δ DO --- dissolved oxygen Reduction amount (mg O₂/L)；X --- mixed genetic-neural network (g/L)；T --- the testing time (h).

1.1.3 ammonia uptake rate (AUR) detection method

Using ammonia electrode on-line determination ammonia nitrogen concentration, AUR is calculated using ammonia nitrogen-T curve straight line portion and sludge concentration, Calculation formula is as follows：

In formula：Ammonia uptake rate (the mg NH of A --- activated sludge₄ ⁺-N/(g TSS·h)]；△NH₄ ⁺-N——NH₄ ⁺-N Reduction amount (the mg NH of concentration₄ ⁺-N/L)；X --- mixed genetic-neural network (g/L)；T --- the testing time (h).

1.1.4 inhibit the calculating of percentage

INT-ETS activity, the unit of each index of SOUR, AUR are different, in order to establish mutual comparativity, then draw Into this index of inhibiting rate, calculation formula is as follows：

In formula：Γ --- heavy metal inhibition percentage (%) active to INT-ETS, SOUR or AUR；X₀--- heavy metal INT-ETS, SOUR or AUR activity value when concentration is 0mg/L；INT-ETS, SOUR or AUR under X --- heavy metal inhibits is living Property value.

Influence of 1.2 environmental factors to heavy metal toxicity

The impact factor of heavy metal toxicity has very much, in general, the concentration and type (valence state) of heavy metal be two most Key factor, other such as pH, microorganism concn (MLSS), sludge age, organic loading, residence time (HRT), dissolved oxygen may also It is key factor.The result of study that this chapter influences denitrification system according to heavy metal, to SBR system sludge concentration, COD load, DO and pH value are controlled, and influence of four kinds of environmental factors to heavy metal toxicity is studied.

1.2.1 influence of the MLSS to heavy metal toxicity

Six parts of precipitating sludges are taken out out of sbr reactor device, it is useless with the beer of COD=400mg/L in the beaker of 1L respectively Sludge concentration is diluted to a certain concentration gradient by water；Add heavy metal ion standard solution respectively, make copper in mixed liquor, cadmium, mercury, Zinc ion concentration respectively reaches 7.5mg/L, 20mg/L, 4.5mg/L, 15mg/L, then starts to be aerated and stir operation, dissolved oxygen It is maintained at 3~4mg/L.It reads ammonia nitrogen concentration online every about 30min and records data.Each sample continuous operation is after 5 hours It is out of service, supernatant detection water outlet COD value is taken after precipitating 15min.Then supernatant is removed, changes to the people that beer is prepared again Work sewage, and restart stirring operation.0.6mL mud mixed liquid is respectively taken to carry out after bringing into operation in each sample immediately INT-ETS Activity determination；Meanwhile mud mixed liquid is taken out from each sample respectively with 6 250mL conical flasks and is sufficiently exposed Gas is inserted into dissolved oxygen electrode after its dissolved oxygen reaches saturation state, carries out dissolved oxygen on-line checking and records data.

1.2.1.1 MLSS is to Cu²⁺The influence of toxicity

(1)Cu²⁺In the presence of MLSS on COD, ammonia nitrogen removal frank influence

Cu²⁺In the presence of, Fig. 2 is shown in influence of the MLSS to COD, ammonia nitrogen removal frank.Sludge concentration is from 2000mg/L to 3000mg/ The COD removal rate of L, system rise to 88.69% from 68.59%, and ammonia nitrogen removal frank rises to 41.67% from 30.01%；Sludge is dense Degree is in 3000mg/L or more, and COD removal rate is maintained at 88% or more variation less, and ammonia nitrogen removal frank is then with the liter of sludge concentration High and continue to increase, ammonia nitrogen removal frank is 54.63% when sludge concentration is 5000mg/L.Cu²⁺In the presence of, improving sludge concentration has Help microorganism and resist copper ion toxicity, wherein nitrobacteria is particularly evident, advantageous to the removal of COD and ammonia nitrogen.

(2)Cu²⁺In the presence of MLSS on microbial activity influence

In different sludge concentrations, the Cu of 7.5mg/L²⁺Fig. 3 is shown in the inhibition situation of sludge activity.With the liter of sludge concentration Height, INT dehydrogenase activity and SOUR are linearly increased；The phenomenon shows that improving sludge concentration is conducive to aerobic heterotrophic microorganism Resist copper ion toxicity.MLSS is in 2000~3000mg/L, and with the increase of sludge concentration, AUR increases severely；Reach 3000mg/L with Certain level was kept when upper.Show that sludge concentration is improved within the scope of 2000~3000mg/L is conducive to the micro- life of chemautotrophy Object --- nitrobacteria resists copper ion toxicity, and sludge concentration is in 4000mg/L or more that then nitrobacteria activity becomes without obvious Change.

1.2.1.2 MLSS is to Cd²⁺The influence of toxicity

(1)Cd²⁺In the presence of MLSS on COD, ammonia nitrogen removal frank influence

Cd²⁺In the presence of, Fig. 4 is shown in influence of the MLSS to COD, ammonia nitrogen removal frank.Sludge concentration is from 1000mg/L to 2000mg/ The COD removal rate of L, system rise to 83.35% from 47.86%, and ammonia nitrogen removal frank rises to 36.05% from 12.85%；Sludge is dense Degree is in 2000~3000mg/L, and COD removal rate rises to 87.43%, and variation is little；And ammonia nitrogen removal frank is then with sludge concentration Raising changes greatly, and ammonia nitrogen removal frank is 49.34% when sludge concentration is 3000mg/L.Sludge concentration is 3000mg/L or more When, ammonia nitrogen and COD removal rate tend towards stability.Sludge concentration is improved in 3000mg/L facilitates microorganism resistance Cd²⁺Toxicity is right The removal of COD and ammonia nitrogen is advantageous.

(2)Cd²⁺In the presence of MLSS on microbial activity influence

In different sludge concentrations, the Cd of 20mg/L²⁺Fig. 5 is shown in the inhibition situation of sludge activity.With the liter of sludge concentration Height, INT- dehydrogenase activity and SOUR are linearly increased, and wherein INT is the most obvious.MLSS in 1000~3000mg/L, with The increase of sludge concentration, AUR increase severely；It is then reduced instead with the raising of MLSS when reaching 3000mg/L or more.In summary：It improves Sludge concentration is conducive to aerobic heterotrophic microorganism and resists Cd²⁺Toxicity；And sludge concentration is improved within the scope of 1000~3000mg/L to be had Conducive to chemautotrophy microorganism --- nitrobacteria resists Cd²⁺Toxicity, but sludge concentration is excessively high and is unfavorable for nitrobacteria instead Existence.

1.2.1.3 MLSS is to Zn²⁺The influence of toxicity

(1)Zn²⁺In the presence of MLSS on COD, ammonia nitrogen removal frank influence

Zn²⁺In the presence of, Fig. 6 is shown in influence of the MLSS to COD, ammonia nitrogen removal frank.Sludge concentration is from 1000mg/L to 4000mg/ The COD removal rate of L, system rise to 66.07% from 40.02%, and ammonia nitrogen removal frank rises to 54.71% from 19.59%；Sludge is dense Degree in 4000mg/L or more, COD removal rate is on a declining curve instead, and ammonia nitrogen removal frank then with the raising of sludge concentration and after Height of continuing rising, ammonia nitrogen removal frank is 68.68% when sludge concentration is 6000mg/L.When sludge concentration is 4000mg/L or more, sludge The raising of concentration facilitates the removal of COD, but excessively high sludge concentration is unfavorable for the removal of COD instead.The raising of sludge concentration Facilitate nitrobacteria and resists zinc ion toxicity, it is advantageous to the removal of ammonia nitrogen.

(2)Zn²⁺In the presence of MLSS on microbial activity influence

In different sludge concentrations, the Zn of 15mg/L²⁺Fig. 7 is shown in the inhibition situation of sludge activity.Sludge concentration be 1000~ SOUR and AUR variation is little when 6000mg/L, and INT- dehydrogenase activity is in wave when sludge concentration is 2000~6000mg/L Dynamic variation downward trend.On the whole, sludge concentration is not significant to zinc ion toxic effect.

1.2.2 influence of the COD load to heavy metal toxicity

The COD value of 6 parts of artificial sewages is adjusted to a certain concentration gradient respectively with beer；It is taken out of sbr reactor device simultaneously Six parts of equivalent precipitating sludges out are respectively respectively diluted sludge concentration with the artificial sewage that the above beer is prepared in the beaker of 1L To 2000mg/L.Heavy metal ion standard solution is added respectively, respectively reaches copper in mixed liquor, cadmium, mercury, zinc ion concentration Then 7.5mg/L, 15mg/L, 3mg/L, 15mg/L start to be aerated and stir operation, dissolved oxygen is maintained at 3~4mg/L.About Every 30min reads ammonia nitrogen concentration online and records data.Each sample continuous operation is out of service after 5 hours, after precipitating 15min Take supernatant detection water outlet COD value.Then supernatant is removed, changes to the artificial sewage that beer is prepared again, and restart to stir Mix operation.0.6mL mud mixed liquid is respectively taken to carry out INT-ETS Activity determination after bringing into operation in each sample immediately；Meanwhile Mud mixed liquid is taken out from each sample respectively with 6 250ml conical flasks to be sufficiently aerated, and reaches saturation to its dissolved oxygen It is inserted into dissolved oxygen electrode after state, carry out dissolved oxygen on-line checking and records data.

1.2.2.1 COD load is to Cu²⁺The influence of toxicity

(1)Cu²⁺In the presence of COD load on COD, ammonia nitrogen removal frank influence

Cu²⁺In the presence of, Fig. 8 is shown in influence of the COD load to COD, ammonia nitrogen removal frank.COD load is from 200mg/L to 400mg/ The COD removal rate of L, system rise to 81.15% from 71.09%, and ammonia nitrogen removal frank rises to 51.65% from 42.56%；COD is negative Lotus drops to 66.50% in 400~600mg/L, COD removal rate, and ammonia nitrogen removal frank is down to 50.03%；COD load is in 600mg/ When L or more, ammonia nitrogen and COD removal rate tend towards stability.Under copper ion inhibits, COD load is improved in 400mg/L and is conducive to ammonia nitrogen With the raising of COD removal rate.Excessively high COD load is unfavorable to the removal of COD, does not make significant difference to the removal of ammonia nitrogen.

(2)Cu²⁺In the presence of COD load on microbial activity influence

In the Cu of 7.5mg/L concentration²⁺In the case of inhibition, COD load is shown in Fig. 9 to microbial activity influence.With COD load Rising, the linear ascendant trend of INT- dehydrogenase activity；Though and SOUR activity increase, its trend is compared with dehydrogenase activity It mitigates；Show that improving COD load is conducive to aerobic heterotrophic microorganism resistance copper ion toxicity.COD load is in 200~1200mg/ The AUR level of L, nitrobacteria are maintained at 0.9~1.0mg NH₄ ⁺- N/ (g TSSh), does not change significantly, COD load pair The activity influence of nitrobacteria is little.

1.2.2.2 COD load is to Cd²⁺The influence of toxicity

(1)Cd²⁺In the presence of COD load on COD, ammonia nitrogen removal frank influence

Cd²⁺In the presence of, Figure 10 is shown in influence of the COD load to COD, ammonia nitrogen removal frank.COD load from 200mg/L to The COD removal rate of 400mg/L, system rise to 89.31% from 71.09%, and ammonia nitrogen removal frank rises to 33.05% from 27.54%. COD load is in 400mg/L or more, and COD removal rate is maintained at 88% or more, and ammonia nitrogen removal frank is maintained at 33% or more, all tends to Stablize.Under Cd2+ inhibits, the raising that COD load is conducive to COD and ammonia nitrogen removal frank is improved in 400mg/L, excessively high COD is negative Lotus does not make significant difference to the removal of COD and ammonia nitrogen.

(2)Cd²⁺In the presence of COD load on microbial activity influence

In 15mg/L concentration C d²⁺In the case of inhibition, COD load is shown in Figure 11 to microbial activity influence.With COD load Increase, INT- dehydrogenase activity is in rising trend；Though and SOUR activity increase, its trend is compared with INT- dehydrogenase activity It mitigates.COD load increases to 0.65mgNH from 0.55 in 200~300mg/L, AUR₄ ⁺-N/(g TSS·h)；COD reaches When 400mg/L, and it is reduced to 0.55mgNH₄ ⁺-N/(g TSS·h)；For COD in 400mg/L or more, AUR is then with the increasing of COD Add and increased, but its Long-term change trend trend is little.In summary, COD load is improved to be conducive to aerobic heterotrophic microorganism and support Anti- Cd²⁺Toxicity, and the activity of nitrobacteria is then influenced smaller.

1.2.2.3 COD load is to Zn²⁺The influence of toxicity

(1)Zn²⁺In the presence of COD load on COD, ammonia nitrogen removal frank influence

Zn²⁺In the presence of, Figure 12 is shown in influence of the COD load to COD, ammonia nitrogen removal frank.COD load from 100mg/L to The COD removal rate of 400mg/L, system rise to 75.18% from 50.09%, and ammonia nitrogen removal frank rises to 61.84% from 49.71%. For COD load in 400mg/L or more, COD removal rate is on a declining curve, and ammonia nitrogen removal frank then continues to rise.Under zinc ion inhibits, The raising that COD load is conducive to COD and ammonia nitrogen removal frank is improved in 400mg/L；Excessively high COD load is unfavorable to the removal of COD, But facilitate the removal of ammonia nitrogen.

(2)Zn²⁺In the presence of COD load on microbial activity influence

In 15mg/L concentration Zn²⁺In the case of inhibition, COD load is shown in Figure 13 to microbial activity influence：With COD load Increase, INT- dehydrogenase activity, SOUR and AUR are in rising trend；Wherein INT- dehydrogenase activity and SOUR ascendant trend compared with To be gentle, and AUR variation tendency is the most obvious.COD load is 100~800mg/L, and AUR increases to 1.38mg NH from 0.48₄ ⁺- N/(g TSS·h)；When COD reaches 800mg/L or more, then tend towards stability.In summary：For aerobic heterotrophic microorganism, mention High COD load is little to zinc ion toxic effect.For nitrobacteria, the raising of COD load is conducive to the life of nitrobacteria It deposits.

1.2.3pH to the influence of heavy metal toxicity

The artificial beer waste water pH value of 6 parts of COD=400mg/L is adjusted to each gradient value respectively with HCl and NaOH；Simultaneously Six parts of equivalent precipitating sludges are taken out out of sbr reactor device, it respectively will with the artificial sewage of the above different pH value in the beaker of 1L Sludge concentration is diluted to 2000mg/L；Heavy metal ion standard solution is added respectively, keeps copper in mixed liquor, cadmium, mercury, zinc ion dense Degree respectively reaches 5mg/L, 15mg/L, 3mg/L, 15mg/L, then starts to be aerated and stir operation, and dissolved oxygen is maintained at 3~ 4mg/L.It reads ammonia nitrogen concentration online every about 30min and records data.Each sample continuous operation is out of service after 5 hours, Supernatant detection water outlet COD value is taken after precipitating 15min.Then supernatant is removed, changes to the artificial sewage that beer is prepared again, and Restart stirring operation.0.6mL mud mixed liquid is respectively taken to carry out INT-ETS activity after bringing into operation in each sample immediately Detection；Meanwhile taking out mud mixed liquid from each sample respectively with 6 250mL conical flasks and being sufficiently aerated, to its dissolution Oxygen is inserted into dissolved oxygen electrode after reaching saturation state, carries out dissolved oxygen on-line checking and records data.

1.2.3.1 pH is to Cu²⁺The influence of toxicity

(1)Cu²⁺In the presence of pH on COD, ammonia nitrogen removal frank influence

Cu²⁺In the presence of, Figure 14 is shown in influence of the pH to COD, ammonia nitrogen removal frank.PH range is between 6.0~7.0, COD removal Rate is in rising trend；PH range is on a declining curve at 7.0~7.5；PH is and in rising trend at 7.5 or more.Ammonia nitrogen is gone Except the variation of rate and COD are different, pH range is in rising trend at 6.0~7.5；PH becomes at 7.5~8.0 in decline Gesture；PH is risen again at 8.0 or more.When pH is 8.5, Cu²⁺It is minimum to aerobic heterotrophism mushroom toxin, most have to COD removal rate Benefit；PH is most advantageous to the removal of ammonia nitrogen when being 7.5.

(2)Cu²⁺In the presence of pH on microbial activity influence

Cu of the activated sludge in 5mg/L concentration²⁺In the case of inhibition, Figure 15 is shown in influence of the pH to microbial activity：INT- is de- Hydrogenase activity and SOUR situation of change are almost the same, except that the variation tendency of SOUR is mitigated compared with dehydrogenase activity；PH model It is trapped among between 6.0~7.0, activity is in rising trend；PH range is on a declining curve at 7.0~7.5；PH at 7.5 or more, It is again in rising trend.AUR is minimum when pH value is equal to 7.5, is 0.81mgNH₄ ⁺-N/(g TSS·h)；When pH rises to 8 or more, Risen again.At 8 or more, SOUR and AUR's pH value increase, the possible reason is copper ion generates Cu (OH)₂ It precipitates and makes the reduction of its toxicity.Under the conditions of pH=6~7.5, faintly acid is all in cooperate with effect with copper ion toxicity with weak basic condition It answers.

1.2.3.2 pH is to Cd²⁺The influence of toxicity

(1)Cd²⁺In the presence of pH on COD, ammonia nitrogen removal frank influence

Cd²⁺In the presence of, Figure 16 is shown in influence of the pH to COD, ammonia nitrogen removal frank.PH range is between 6.0~7.0, COD removal Rate is on a declining curve with ammonia nitrogen removal frank；For pH range at 7.0 or more, COD is in rising trend with ammonia nitrogen removal frank.Weak base Property can reduce Cd2+ to the toxicity of microorganism, be conducive to the removal rate to COD and ammonia nitrogen.

(2)Cd²⁺In the presence of pH on microbial activity influence

Activated sludge is in 15mg/L concentration C d²⁺In the case of inhibition, Figure 17 is shown in influence of the pH to microbial activity：INT- dehydrogenation Enzymatic activity and SOUR situation of change are almost the same；For pH range between 6.0~6.5, activity change is little；PH range 6.5~ It is on a declining curve when 7.0；PH is and in rising trend at 7.5 or more.AUR on a declining curve, pH when pH is 6.0~7.0 Then in rising trend when being 7.0~8.0, pH is on a declining curve at 8.0 or more.From the analysis above, we can see that：Weak acid is equal with alkalescent With Cd²⁺Toxicity is in antagonism.

1.2.3.3 pH is to Zn²⁺The influence of toxicity

(1)Zn²⁺In the presence of pH on COD, ammonia nitrogen removal frank influence

Zn²⁺In the presence of, Figure 18 is shown in influence of the pH to COD, ammonia nitrogen removal frank.PH range is between 6.0~7.0, COD removal Rate is risen；For pH range at 7.0 or more, COD is on a declining curve.On the whole, ammonia nitrogen removal frank with pH raising Rise.In conclusion in Zn²⁺In the presence of in the case of, the raising of pH is conducive to the removal of ammonia nitrogen；And weak acid and alkalescent are all unfavorable for The removal of COD.

(2)Zn²⁺In the presence of pH on microbial activity influence

Activated sludge is in 15mg/L concentration Zn²⁺In the case of inhibition, Figure 19 is shown in influence of the pH to microbial activity.PH=4.0 When~6.0：SOUR and AUR increase sharply to 28.83mg O from 19.20 and 0.01 respectively₂/ (g TSSh) and 0.31mgNH4+-N/ (g TSS·h)；And INT- dehydrogenase activity is down to 140.39mg INTF/ (g TSSh) from 149.28, changes smaller.PH= When 6.0~7.0：SOUR and AUR decrease；INT- dehydrogenase activity but increases.When pH=7.0~8.0：SOUR and AUR is increased, and INT- dehydrogenase activity is on a declining curve.When pH > 8.0：INT- dehydrogenase activity, SOUR and AUR It is on a declining curve.From the analysis above, we can see that：Zn²⁺Under inhibiting effect, microorganism SOUR and AUR are affected by pH, compare it Lower dehydrogenase activity is influenced smaller by pH.

1.2.4DO to the influence of heavy metal toxicity

Six parts of equivalent precipitating sludges are taken out out of sbr reactor device, use the people of COD=400mg/L respectively in the beaker of 1L Sludge concentration is diluted to 2000mg/L by work beer waste water.Add heavy metal ion standard solution respectively, make copper in mixed liquor, Cadmium, mercury, zinc ion concentration respectively reach 5mg/L, 15mg/L, 3mg/L, 15mg/L.Then start to be aerated and stir operation, pass through The average DO that adjusting aeration intensity controls each mud mixed liquid reaches certain gradient value.It is dense to read ammonia nitrogen online every about 30min It spends and records data.Each sample continuous operation is out of service after 5 hours, takes supernatant detection water outlet COD after precipitating 15min Value.Then supernatant is removed, changes to the artificial sewage that beer is prepared again, and restart stirring operation.It is stood after bringing into operation 0.6mL mud mixed liquid is respectively taken to carry out INT-ETS Activity determination in each sample；Meanwhile being divided with 6 250mL conical flasks Mud mixed liquid is taken out not from each sample to be sufficiently aerated, and dissolved oxygen electricity is inserted into after its dissolved oxygen reaches saturation state Pole carries out dissolved oxygen on-line checking and records data.

1.2.4.1 DO is to Cu²⁺The influence of toxicity

(1)Cu²⁺In the presence of DO on COD, ammonia nitrogen removal frank influence

Cu²⁺In the presence of, Figure 20 is shown in influence of the DO to COD, ammonia nitrogen removal frank.With the increase of DO, COD removal rate is in decline Trend, ammonia nitrogen removal frank are in rising trend.Copper ion is in synergistic effect to the toxicity of aerobic heterotroph and the increase of dissolved oxygen, but Be conducive to the removal of ammonia nitrogen.

(2)Cu²⁺In the presence of DO on microbial activity influence

Activated sludge is in 5mg/L concentration C u²⁺In the case of inhibition, DO is shown in Figure 21 to microbial activity influence：Average dissolution oxygen In 1mg/L or less, SOUR variation is little, and after dissolved oxygen is increased to 1mg/L or more, then it is on a declining curve.INT- dehydrogenase Activity increases within the scope of 1mg/L or less low dissolved oxygen with the raising of dissolved oxygen concentration, when average dissolution oxygen increases It is then in sharply downward trend when to 1mg/L or more.It seeing on the whole, AUR is increased with the raising of average dissolution oxygen, Especially average dissolution oxygen ascensional range within the scope of 0.1~2.5mg/L is maximum.By the above phenomenon：Press down in copper ion In the case of system, low dissolved oxygen is conducive to improve dehydrogenase activity and SOUR.To removal organic matter leading role --- chemoheterotrophy is micro- For biology, improving dissolved oxygen concentration to a certain extent may advantageously facilitate its activity, but excessively high dissolved oxygen is again obviously and copper Ion toxicity plays synergistic effect.Microorganism is set to rapidly deplete organic substrates and exhale too early into endogenous the reason is that crossing high-solubility oxygen The suction phase, and copper ion is bigger to the Ecotoxicology of endogenous respiratory period, or even microorganism is made to be poisoned to death and decompose.For nitrification For bacterium, the increase of dissolved oxygen can be such that its activity improves within the scope of 0~3mg/L.

1.2.4.2 DO is to Cd²⁺The influence of toxicity

(1)Cd²⁺In the presence of DO on COD, ammonia nitrogen removal frank influence

Cd²⁺In the presence of, Figure 22 is shown in influence of the DO to COD, ammonia nitrogen removal frank.DO is in 0~1.65mg/L, with the increasing of DO Greatly, COD and ammonia nitrogen removal frank are in rising trend.DO is in 1.65mg/L or more, with the raising of DO, under COD removal rate is in Drop trend.In 2.75~4.01mg/L, ammonia nitrogen removal frank is declined DO；DO is in 4.01~5.62mg/L, ammonia nitrogen removal Rate is increased；In 5.62mg/L or more, ammonia nitrogen removal frank reduces DO with the raising of DO.In conclusion DO is in 1.65mg/ Raising within the scope of L is conducive to the removal of COD, but excessively high DO is unfavorable for the removal of COD again.For nitrobacteria, put down For equal DO in 2.756mg/L or less, the raising of DO facilitates the removal of ammonia nitrogen, but excessively high DO is equally unfavorable for going for ammonia nitrogen It removes.

(2)Cd²⁺In the presence of DO on microbial activity influence

Activated sludge is in 15mg/L concentration C d²⁺In the case of inhibition, DO is shown in Figure 23 to microbial activity influence：Average dissolution oxygen In 1.2mg/L or less, INT- dehydrogenase activity and SOUR are on a declining curve, and wherein SOUR and INT- dehydrogenase activity is more Obviously.And dissolved oxygen, in 1.2~1.6mg/L, SOUR rises to 70.38mg O from 53.16₂/(g TSS·h)；INT- dehydrogenation Enzymatic activity is then on a declining curve.For average DO in 1.6mg/L or more, then INT- dehydrogenase activity and SOUR are on a declining curve. Compared with INT- dehydrogenase activity and SOUR, AUR variation tendency is more different：For average DO in 1.6mg/L or less, AUR is with DO Increase and linear ascendant trend；For DO in 1.6~2.7mg/L, AUR variation is little；DO in 2.6~4.0mg/L, AUR sharply under Drop；For DO in 4.0mg/L or more, AUR is in rising trend, but variation tendency is relatively slow.It to sum up analyzes, high-solubility oxygen and Cd²⁺Toxicity rises Synergistic effect is unfavorable for improving dehydrogenase activity.For nitrobacteria, DO is averaged in 1.6mg/L or less, dissolved oxygen Increase can be such that its activity improves, but excessively high dissolved oxygen equally promotes Cd²⁺Toxic action to nitrobacteria.

1.2.4.3 DO is to Zn²⁺The influence of toxicity

(1)Zn²⁺In the presence of DO on COD, ammonia nitrogen removal frank influence

Zn²⁺In the presence of, Figure 24 is shown in influence of the DO to COD, ammonia nitrogen removal frank.DO is in 0~1.72mg/L, with the increasing of DO Greatly, COD removal rate is in rising trend；Though ammonia nitrogen removal frank is increased, its trend is gentle compared with COD.DO 1.72mg/L with When upper, with the raising of DO, COD removal rate is on a declining curve, and ammonia nitrogen removal frank tends to balance.In conclusion Zn²⁺In the presence of, Raising of the DO within the scope of 1.72mg/L is conducive to the removal of COD, but excessively high DO is unfavorable for the removal of COD again；DO is to ammonia nitrogen Removal do not make significant difference.

(2)Zn²⁺In the presence of DO on microbial activity influence

Activated sludge is in 15mg/L concentration Zn²⁺In the case of inhibition, DO is shown in Figure 25 to microbial activity influence：DO 0~ 1.72mg/L when：INT- dehydrogenase activity, SOUR and AUR are increased with the increase of DO, and wherein the variation tendency of AUR is the brightest It is aobvious.And DO in 1.72mg/L or more, then with the increase of DO, INT- dehydrogenase activity, SOUR and AUR are on a declining curve.It is comprehensive Upper analysis：For DO in 0~1.72mg/L, zinc ion toxicity can be reduced by improving dissolved oxygen；But dissolved oxygen is in 1.72mg/L or more, It is then little to zinc ion toxic effect to improve DO.

1.2.5 this section brief summary

(1) in Cu²⁺And Cd²⁺Under toxic action, improve sludge concentration can be obviously promoted microbial dehydrogenation enzymatic activity and SOUR facilitates aerobic heterotrophic microorganism and resists heavy metal ion toxicity；Sludge concentration is improved within 3000mg/L to be conducive to promote The AUR of nitrobacteria, chemautotrophy microorganism --- nitrobacteria resists its toxicity for assistance, meanwhile, the removal rate of COD and ammonia nitrogen Increase；In contrast, in the presence of zinc ion, although sludge concentration is to microorganism INT-ETS activity, SOUR and AUR Influence is all smaller, but the raising of sludge concentration is conducive to improve ammonia nitrogen removal frank.

(2)Cu²⁺And Cd²⁺In the presence of, COD load is improved in 400mg/L is conducive to improve mentioning for COD and ammonia nitrogen removal frank Height, excessively high DO is unfavorable for the removal of COD again, and does not make significant difference to the removal rate of ammonia nitrogen.Excessively high COD load is unfavorable for The removal of COD does not make significant difference to the removal of ammonia nitrogen.Zn²⁺Under inhibition, in 400mg/L improve COD load be conducive to COD and The raising of ammonia nitrogen removal frank；Excessively high COD load is unfavorable to the removal of COD, but facilitates the removal of ammonia nitrogen.In Cu²⁺And Cd²⁺ Under toxic action, improving COD load may advantageously facilitate microorganism INT-ETS activity and SOUR；And Zn²⁺In the presence of, then without significant It influences.Cu²⁺And Cd²⁺In the presence of, COD load does not make significant difference to nitrobacteria AUR；Zn²⁺In the presence of, improve COD load instead It can promote AUR.

(3)Cu²⁺And Cd²⁺In the presence of, neutral and alkalescent is conducive to the removal rate to COD and ammonia nitrogen.In Zn²⁺There are feelings Under condition, the raising of pH is conducive to the removal of ammonia nitrogen；And weak acid and alkalescent are all unfavorable for the removal of COD.The condition of pH=6~7.5 Under, faintly acid and weak basic condition all with Cu²⁺Toxicity is in synergistic effect.Under the conditions of pH=6~8.0, weak acid and alkalescent with Cd²⁺Toxicity is in antagonism.Under the conditions of pH=4~9, Zn²⁺In the presence of, microorganism SOUR and AUR are affected by pH, phase INT-ETS activity is influenced smaller by pH than under.

(4) raising of DO and heavy metal toxicity generally play synergistic effect, are unfavorable for mentioning for microbial activity and COD removal rate It is high.For nitrobacteria, for average DO in 1.5mg/L or less, the increase of dissolved oxygen can be such that its AUR improves, but excessively high Dissolved oxygen equally promote toxic action of the heavy metal ion to nitrobacteria.

Influence of 1.3 heavy metals to activated sludge INT-ETS activity, SOUR, AUR

1.3.1 Cu²⁺Influence to activated sludge INT-ETS activity, SOUR, AUR

1.3.1.1 Cu²⁺On the active influence of activated sludge INT-ETS

Copper ion concentration is shown in Figure 26 to the inhibition situation of microorganism electron transport system activity.It can be seen from the figure that copper When ion concentration is from 0mg/L to 0.5mg/L, to microorganism INT-ETS activity not only without inhibiting effect, there is certain rush instead Into effect；When being increased to 2mg/L or more with copper ion concentration, INT-ETS activity is in apparent downward trend；Show to be more than this The copper ion of concentration generates significant inhibiting effect to microorganism.When copper ion concentration reaches 7mg/L, INT-ETS activity drop It is 50% or less initial value to 90mg INTF/ (gTSSh).When copper ion concentration reaches 10mg/L, INT-ETS is living Property is reduced to 50mg INTF/ (gTSSh).

1.3.1.2 Cu²⁺Influence to activated sludge SOUR and AUR

Influence result of the copper ion concentration to SOUR and AUR is shown in Figure 27.From the figure, it can be seen that copper ion concentration 0~ When within the scope of 0.5mg/L, to the SOUR of Microbial Communities in Activated Sludge not only without inhibiting effect, there is certain promotion to make instead With；With the raising of copper ion, when copper ion concentration reaches 1mg/L or more, significant inhibiting effect just is generated to microorganism. When copper ion concentration reaches 5mg/L, SOUR has been reduced to 50% or less initial value.When copper ion concentration reaches 10mg/L, Its SOUR has been reduced to the 16% of initial value.AUR change curve is observed, when copper ion concentration is within the scope of 0~0.5mg/L, There is certain inhibiting effect to the AUR activity of Microbial Communities in Activated Sludge, and with the raising of copper ion concentration, micro- life The linear downward trend of object AUR activity.When copper ion concentration reaches 5mg/L, AUR have been reduced to the 39% of initial value with Under.When copper ion concentration reaches 10mg/L, AUR has been reduced to the 22% of initial value, this concentration copper ion is thin to nitrogen oxidation Bacterium activity has significantly inhibiting property.

1.3.1.3 Cu²⁺Influence to dephosphorization system microbial activity

Figure 28 is shown in copper ion influence active on dephosphorization system microorganism INT-ETS respectively.In 0~60min anaerobism section, 0 The copper ion of~0.5mg/L starts INT-ETS activity to generate inhibiting effect；When copper ion concentration is in 1mg/L or more, just with The raising of copper ion concentration, INT-ETS activity be decreased obviously, system microbial activity is significantly inhibited.In aerobic section, The copper ion of 0~4mg/L is small compared with anaerobism section to INT activity influence, when copper ion concentration is 5mg/L or more, just to INT-ETS Show obvious inhibiting effect.So INT-ETS activity characterization copper ion is to anaerobe toxicity under copper ion inhibition Sensitivity it is preferable, and in aerobic section, just there is apparent inhibiting effect in INT-ETS activity when copper ion concentration is higher, table It is lower than anaerobic stages to levy sensitivity.

1.3.2 Zn²⁺Influence to activated sludge INT-ETS activity, SOUR, AUR

1.3.2.1 Zn²⁺On the active influence of activated sludge INT-ETS

Zn²⁺Figure 29 is shown in ETS activity suppression situation, as we can see from the figure：With Zn²⁺The increase of concentration, INT-ETS Activity is presented wave and changes and gradually decrease trend, and 219.99mgINTF/ (g TSSh) of the activity by drops to 55.56mgINTF/(g TSS·h)；Zn²⁺Concentration just generates inhibiting effect, and concentration to INT-ETS activity in 5mg/L In 5~25mg/L, the decline of INT-ETS activity is the most obvious, and 50% when in 25mg/L, activity has dropped to beginning.Explanation INT-ETS activity can reflect Zn well²⁺Toxic action to microorganism.

1.3.2.2 Zn²⁺Influence to activated sludge SOUR and AUR

Zn²⁺Influence result to SOUR and AUR is shown in Figure 30, as shown in the figure：Zn²⁺Concentration be 0~5mg/L when, SOUR from 56.74 rising to 60.19mg O₂/ (g TSSh) has and is obviously promoted effect；Concentration just produces SOUR in 5mg/L or more Raw obvious inhibition, and with Zn²⁺The raising of concentration and be in decreasing trend；When zinc ion concentration is to 20mg/L, SOUR is down to 22.70mg O₂/ (g TSSh), and with Zn²⁺Concentration increase and it is on a declining curve；Zn²⁺When concentration rises to 80mg/L, SOUR is only For 5.08mg O₂/(g TSS·h).AUR change curve is observed it is found that Zn²⁺When concentration is 0~5mg/L, AUR is influenced little； With the raising of concentration, Zn²⁺Apparent inhibiting effect is just generated to AUR；When concentration is 10mg/L, AUR is from initial value 3.00mg NH₄ ⁺- N/ (g TSSh) drops to 2.13mg NH₄ ⁺-N/(g TSS·h)；When concentration reaches 40mg/L, AUR drop To 0.38mg NH₄ ⁺-N/(g TSS·h)；Zn²⁺When concentration reaches 80mg/L, nitrification is thoroughly lost.

1.3.2.3 Zn²⁺Influence to dephosphorization system microbial activity

Zn²⁺Figure 31 is shown in dephosphorization system microorganism INT-ETS activity influence.In anaerobism section, Zn²⁺Respectively in 3 and 5mg/L When start to generate INT-ETS activity obvious inhibit；With Zn²⁺The raising of concentration, inhibiting effect increase.In aerobic section, activity Inhibit situation and anaerobism section different：Zn²⁺Concentration has certain facilitation in 10mg/L or less to INT-ETS activity； When 10mg/L or more, inhibiting effect increases with the raising of zinc ion concentration.So can good table using INT-ETS activity Levy Zn²⁺Influence to dephosphorization system microbial activity, and the sensitivity of activity of anaerobic sludge inhibition is characterized than aerobic stage It is high.

1.3.3 Cd²⁺Influence to activated sludge INT-ETS activity, SOUR, AUR

1.3.3.1 Cd²⁺On the active influence of activated sludge INT-ETS

Cd²⁺Figure 32 is shown in INT-ETS activity suppression situation.As can be seen that Cd from INT curve²⁺Concentration is in 0~1mg/L When, INT-ETS activity drops to 151.26mg INTF/ (g TSSh) from 171.15mg INTF/ (g TSSh), reduces 11.6%；When rising to 2mg/L from 1mg/L, and 163.02mg INTF/ (g TSSh) is risen to, improves 7.8%, but still Lower than initial value；Work as Cd²⁺When concentration is greater than 2mg/L, just start linear downward trend.Work as Cd²⁺When concentration reaches 30mg/L, Only 38.77mg INTF/ (g TSSh), than initial value decline 77%.Illustrate INT-ETS activity characterization Cd²⁺To micro- in system The toxic action of biology has very high sensitivity, can reflect Cd²⁺To the inhibition situation of nitrobacteria.

1.3.3.2 Cd²⁺Influence to activated sludge SOUR and AUR

Cd²⁺Influence result to SOUR and AUR is shown in Figure 33.Cd²⁺Concentration is in 0~1mg/L range, to activated sludge The SOUR of middle microorganism has certain facilitation.Cd²⁺Concentration SOUR activity highest in 2mg/L, reaches 44mg O₂/(g TSSh), higher than initial value by 23.2%.With Cd²⁺The raising of concentration when reaching 10mg/L or more, just generates microorganism aobvious The inhibiting effect of work.Cd²⁺When concentration reaches 30mg/L, SOUR has been reduced to the 39.7% of initial value.In the Cd of low concentration²⁺ In, SOUR shows apparent increase trend, the possible reason is in Cd²⁺Under toxicity inhibition, a large amount of oxygen ratios of cellular uptake are certainly Body respiration more likely resists extraneous toxicity impact.Observe AUR change curve, Cd²⁺When concentration is within the scope of 0~1mg/L, It has had certain inhibiting effect to the AUR activity of Microbial Communities in Activated Sludge；Cd²⁺Though concentration 1~2mg/L on It rises, but still it is smaller than initial value.With Cd²⁺The raising of concentration, the linear downward trend of microorganism AUR activity.Cd²⁺Concentration reaches When to 30mg/L, AUR has been reduced to the 19% of initial value.In conjunction with Fig. 4-34：AUR activity and ammonia nitrogen removal frank curve extremely phase Seemingly.It is concluded that：Cd²⁺In the presence of, AUR is the optimal index for characterizing nitrobacteria activity and nitrification effect.

1.3.3.3 Cd²⁺Influence to dephosphorization system microbial activity

Cd²⁺Figure 34 is shown in dephosphorization system microorganism INT-ETS activity influence.In 0~60min anaerobism section, 20mg/L's Cd²⁺INT-ETS activity is started to generate apparent inhibiting effect；With Cd²⁺Concentration continues to increase, INT-ETS activity suppression It becomes apparent.In aerobic section, work as Cd²⁺When concentration is 20mg/L or more, with Cd²⁺The raising of concentration, the inhibition to INT-ETS Effect significantly improves.Found out by test, in Cd²⁺Under inhibition, INT-ETS activity characterization Cd²⁺To the sensitive of anaerobe toxicity Property is preferable；And in aerobic section, sensitivity is not high.

1.3.4 Cr⁶⁺Influence to activated sludge INT-ETS activity, SOUR, AUR

1.3.4.1 Cr⁶⁺On the active influence of activated sludge INT-ETS

Cr⁶⁺Influence situation active on sludge INT-ETS is as shown in figure 35.Heavy metal Cr⁶⁺To the INT- of sludge system The active influence of ETS is relatively obvious.When Cr is added in sludge system⁶⁺Afterwards, the linear downward trend of sludge INT-ETS activity.When Cr⁶⁺When concentration is increased to 45.0mg/L, blank test is compareed, INT-ETS activity decrease beyond 60%, is reduced to 157.97mg The left and right INTF/ (mg TSSh).Later with Cr⁶⁺The continuous raising of concentration, INT-ETS activity downward trend tend towards stability, when Cr⁶⁺When concentration reaches 70.0mg/L, INT-ETS activity is reduced to 100mg INTF/ (mg TSSh) below.Analyzing reason can It can be because of high concentration Cr⁶+ nitrobacteria and denitrifying bacteria can be damaged, so that microbial cell is lost activity, from And influence entire biological treatment system.

1.3.4.2 Cr⁶⁺Influence to activated sludge SOUR and AUR

Cr⁶⁺It is as shown in figure 36 that situation is influenced on sludge SOUR and AUR.As seen from the figure, when biological treatment system is by Cr⁶⁺ When coercion, sludge SOUR and AUR can show corresponding impact effect earlier.It can be seen that work as from SOUR curve and be Heavy metal Cr is added in system⁶⁺Afterwards, the linear downward trend of sludge SOUR.Work as Cr⁶⁺When concentration is increased to 60.0mg/L, sludge SOUR activity is reduced to 12.68mg O2/ (mg MLSSh), relative to blank control group, 75% or more sludge SOUR decline. Work as Cr⁶⁺When concentration is increased to 70.0mg/L, sludge SOUR activity is reduced to 1.0mg O₂/ (mg MLSSh) is below.Relative to For SOUR, sludge AUR is by Cr⁶⁺It influences more obvious.Work as Cr⁶⁺When concentration is increased to 30.0mg/L, sludge AUR and blank are tried It tests compared to decline 50%.Later with Cr⁶⁺The increase of concentration, the suppressed situation of sludge AUR tend towards stability.Work as Cr⁶⁺Concentration increases When to 60.0mg/L, sludge AUR is reduced to 1.0mg NH⁴⁺- N/ (g MLSSh) is below.Work as Cr⁶⁺Concentration is increased to 70.0mg/ When L, sludge AUR, which shines, reduces by 75% than blank assay group.

1.3.5 this section brief summary

(1) experimental study of denitrification system is obtained to draw a conclusion：

1. biological denitrification system, after gradually increasing concentration of heavy metal ion, the activity of activated sludge, which shows, gradually to drop Low trend, the sequence that 4 metal ion species influence sludge activity are：Cu²⁺> Cd²⁺> Zn²⁺> Gr⁶⁺。

②Cu²⁺On in the active influence of the denitrifying sludge of system, AUR activity can most reflect the suppressed effect of sludge activity； In Cd²⁺INT-ETS activity can most reflect Cd in research²⁺Influence to the sludge activity of sludge organism denitrification system；And in Zn²⁺ And Gr⁶⁺In research, AUR activity can most reflect the suppressed effect of sludge activity；

3. the inhibition of 4 heavy metal species ion pair nitrification effects is all larger than the inhibition of the decomposition to organic matter；With heterotroph It compares, nitrobacteria is more sensitive to various heavy metal ion toxicity.

(2) it is obtained by the experimental study to dephosphorization system to draw a conclusion：

1. copper, cadmium, 3 heavy metal species ion concentration of zinc start in 4mg/L, 20mg/L, 10mg/L or more to water outlet respectively Total phosphorus concentration generation significantly affects；3 heavy metal species influence size order to biological phosphor-removing effect：Cu²⁺> Zn²⁺> Cd²⁺。

2. in anaerobism section：Under heavy metal ion inhibits, 3 heavy metal species are to anaerobic activated sludge INT-ETS activity suppression Toxicity size order is：Cu²⁺> Zn²⁺> Cd²⁺。

3. in aerobic section：3 heavy metal species are respectively to the toxicity size order of INT-ETS activity suppression：Cu²⁺> Zn²⁺> Cd²⁺。

Influence of 1.4 heavy metals to microbial activity inhibiting rate

1.4.1 Cu²⁺Influence to microbial activity inhibiting rate

Figure 37 is shown in influence of the copper ion to microbial activity inhibiting rate.INT-ETS, SOUR and AUR activity 503nhibiting concentration (concentration of heavy metal when as inhibiting rate Γ=50%) is respectively：7.27mg/L, 5.90mg/L and 5.48mg/L.So may be used Know：Under by copper ion toxic action, SOUR maximum inhibition is sensitive compared with ETS activity；And AUR maximum inhibition then can be very Good characterization system nitrification effect is by being inhibited situation.

1.4.2 Zn²⁺Influence to microbial activity inhibiting rate

Zn²⁺Figure 38 is shown in influence to microbial activity inhibiting rate.As shown in the figure：INT-ETS, SOUR and AUR activity half presses down Concentration processed is respectively 36.85,24.59 and 25.82mg/L.It draws a conclusion：SOUR more can be characterized more delicately compared with INT-ETS activity Zn²⁺Toxicity；AUR also can accurately, delicately characterize the suppressed situation of nitrification effect institute.

1.4.3 Cd²⁺Influence to microbial activity inhibiting rate

Cd²⁺Figure 39 is shown in influence to microbial activity inhibiting rate.It can be seen from the figure that INT-ETS, AUR, SOUR half presses down Concentration processed is 18.97,19.42mg/L and 29.71mg/L, and trend is more similar, and the nitrification effect that can characterize system inhibits feelings Condition, wherein the 503nhibiting concentration of INT-ETS is minimum, more can it is sensitive, accurately characterize Cd²⁺Toxic action.

1.4.4 Cr⁶⁺Influence to microbial activity inhibiting rate

Cr⁶⁺Figure 40 is shown in influence to microbial activity inhibiting rate.It can be seen from the figure that INT-ETS, AUR, SOUR half presses down Concentration processed is 39.63mg/L, 33.19mg/L and 45.92mg/L, and three is not much different, and slope is basic, can characterize the one of system Cause, the inhibition situation of nitrification effect can be reacted, wherein the 503nhibiting concentration of AUR is minimum, more can it is sensitive, accurately characterize Cr⁶⁺ Toxic action.

1.4.5 this section brief summary

(1) 4 each activity index of heavy metal species ion pair denitrification system toxicity half-suppressed (toxicity half-suppressed：That is inhibiting rate etc. In 50% toxicity size, the smaller toxicity then half-suppressed of 503nhibiting concentration is bigger) it is sequentially different, INT-ETS and SOUR are living The sequence of property is：Cu²⁺> Cd²⁺> Zn²⁺> Cr⁶⁺；The active sequence of AUR is：Cu²⁺> Zn²⁺> Cd²⁺> Cr⁶⁺。

The inhibition of (2) 4 heavy metal species ion pair nitrification effects is all larger than the inhibition of the decomposition to organic matter；With heterotroph It compares, nitrobacteria is more sensitive to various heavy metal ion toxicity.

(3) each heavy metal species are different to the inhibiting mechanism of active sludge microorganism, should be comprehensive in conjunction with each reactivity parameter Characterize its toxic action.AUR can characterize copper, chromium heavy metal to the toxicity of nitrifying microorganisms；In the presence of copper, zinc ion, SOUR is Characterize its optimal parameter to aerobic heterotrophic microorganism toxicity；And in the presence of cadmium ion, INT-ETS is to characterize it to aerobic heterotrophism The optimal parameter of Ecotoxicology.

Comparison of 1.5 heavy metals to bioactivity toxic effect evaluation index sensitivity level

When sewage biological treatment system is acted on by high concentration heavy metal stress, organic matter degradation, contaminants removal And sludge INT-ETS activity, SOUR, AUR etc. can be all influenced to different extents.EC50：Half-maximal effect concentration Concentration for 50%of maximal effect.By comparing EC50 value, variety classes heavy metal can be determined To the size of each poisonous effect evaluation index sensitivity level of microorganism.Meanwhile the determination of EC50 can be by SPSS software come complete At, have research it has been confirmed that, SPSS software have powerful and perfect function of statistic analysis, possess complete data access, number Function is presented according to management and data, treated that result is more accurate compared with same type software for analysis, and is more nearly manual calculation As a result.By calculating, the EC50 of different toxic effect evaluation indexes is obtained, see Table 1 for details.

1 toxic effect evaluation index EC50 value of table

	INT-ETS activity	SOUR	AUR
				Cu²⁺	7.209	6.347	5.833
Cd²⁺	17.649	23.237	16.561
				Zn²⁺	34.523	22.499	29.503
Cr⁶⁺	35.052	48.325	33.778

As shown in Table 1, when Cu is added in microflora²⁺When, relative to other two kinds of evaluation indexes (INT-ETS activity, SOUR activity), EC50 corresponding to sludge AUR activity is minimum, is 5.833, illustrates in three kinds of toxic effect evaluation indexes, sludge AUR activity characterization Cu²⁺The sensitivity influenced on the toxic effect of microbial activity is most strong, selectes sludge AUR activity as characterization Cu² ⁺The evaluation index that the toxic effect of microbial activity is influenced.Similarly, when Cd is added in microflora²⁺When, sludge AUR activity Corresponding EC50 is minimum, is 16.561, illustrates in three kinds of toxic effect evaluation indexes, sludge AUR activity characterization Cd²⁺To micro- life The sensitivity that the active toxic effect of object influences is most strong.Selected sludge AUR activity is as characterization Cd²⁺To the toxic effect of microbial activity The evaluation index of influence.When Zn is added in microflora²⁺When, it is 22.499 that EC50 corresponding to sludge SOUR activity is minimum, Illustrate in three kinds of poisoning effect evaluation indexes, sludge SOUR activity characterization Zn²⁺The spirit that the toxic effect of microbial activity is influenced Quick property is most strong.Selected sludge SOUR activity is as characterization Zn²⁺The evaluation index that the toxic effect of microbial activity is influenced.When micro- life Cr is added in object system⁶⁺When, EC50 corresponding to sludge AUR activity is minimum, is 33.778, indicates to use sludge AUR activity table Levy Cr⁶⁺The sensitivity influenced on the toxic effect of microbial activity is most strong, as characterization Cr⁶⁺To the toxic effect shadow of microbial activity Loud evaluation index.

The EC50 value that sludge activity influences is found out from four heavy metal species, sludge AUR activity characterization wherein three heavy metal species (Cu²⁺, Cd²⁺, Cr⁶⁺) sensitivity highest influenced on the toxic effect of microbial activity, and heavy metal Zn²⁺EC50 value in AUR value ratio SOUR value is slightly higher, in characterization Zn²⁺Also sensitivity with higher is influenced on the toxic effect of microbial activity, in conjunction with four heavy metal species The toxic effect of ion influences situation, and final selected sludge AUR activity is as characterization heavy metal to microbial activity toxic effect The evaluation index of influence.

2 metal of embodiment evaluates microbial activity poisonous effect

For municipal sewage biological treatment, heavy metal ion is studied to the poison of microorganism in biological wastewater treatment process Property effect, analysis heavy metal stress effect under activity of activated sludge changing rule, need further to improve sewage plant into The threshold value of heavy metal toxicity in water is studied using a variety of comprehensive toxicity detection methods, determines relatively accurate heavy metal poison Property secure threshold.Meanwhile bringing comprehensive toxicity index in water environment management standard into, it uses based on being analyzed with physical and chemical index, Method supplemented by comprehensive toxicity index is monitored in real time and is managed to water environment.Conclusion number before In this Section analysis According to establishing characterization heavy metal toxicity influences the evaluation criterion of grade, provides rationalization reason for the normal operation of biological treatment It lays the groundwork by foundation.

Currently, domestic unified microbial activity toxicity detection grading standard not yet.This research is with reference to Nanjing soil The percentage classification standard that earth research institute is recommended differentiates heavy metal to the size of Ecotoxicology, and see Table 2 for details.

2 toxicity assessment standard of table

Toxic grade	Relative luminous rate Γ %
		It is nontoxic	Γ < 10
Low toxicity	10≤Γ < 30
		Poisoning	30≤Γ < 50
Weight poison	50≤Γ < 70
		High poison	70≤Γ < 100
Severe toxicity	Γ=100

Toxic grade is determined by microbial activity inhibiting rate, utilizes different microorganisms activity in corresponding toxicities rate range The suppressed situation of evaluation index and NH₄ ⁺Relationship between-N removal rate, COD removal rate, it is final to establish characterization heavy metal toxicity shadow Ring the evaluation criterion of grade.By foregoing description it is found that being gone when sewage disposal system is by heavy metal stress relative to COD Except rate, NH₄ ⁺The situation of change of-N removal rate becomes apparent, therefore this test is mainly according to NH₄ ⁺The situation of change of-N removal rate is true Determine heavy metal toxicity classification standard.

This controlling test inlet COD concentration is in 300mg/L or so, NH₄ ⁺- N is controlled in 30mg/L or so, to make effluent quality Reach level-one emission standard A, needs to control effluent COD concentration within 50mg/L, NH₄ ⁺- N concentration is within 8mg/L, this needs Sludge removal rate is set to reach 80% or more, therefore, with 80%NH₄ ⁺- N removal rate, COD removal rate define the nontoxic of heavy metal toxicity State, and heavy metal ion divides microbial activity toxic effect grade in conjunction with table 5-2 toxicity assessment standard.

1.1 Cu²⁺Division to microbial activity toxic effect grade

AUR maximum inhibition and sewage disposal system NH₄ ⁺Relationship between-N removal rate is as shown in figure 41.

As shown in Figure 41, when Cu is added in activated Sludge System²⁺Afterwards, sludge AUR maximum inhibition and NH₄ ⁺- N removal rate Good correlation is presented, illustrating to work as has Cu²⁺When participating in reaction, sludge AUR activity can preferably reflect sludge activity Situation of change.Therefore, it can use sludge AUR maximum inhibition as judgement heavy metal Cu²⁺The evaluation index of toxicity.Reference table 2 toxicity assessment standards divide heavy metal Cu²⁺Toxic grade standard, see Table 3 for details.

3 toxic grade standard of table

Toxic grade	Removal rate % (R)	AUR maximum inhibition % [EC (A)]
			It is nontoxic	Greater than 80	Less than EC40
Low toxicity	70~80	EC40~EC60
			Poisoning	50~70	EC60~EC70
Severe	30~50	EC70~EC90
			High poison	0~30	EC90~EC100
Severe toxicity	Equal to 0	Equal to EC100

1.2 Cd²⁺Division to microbial activity toxic effect grade

AUR maximum inhibition and sewage disposal system NH₄ ⁺Linear relationship between-N removal rate is as shown in figure 42.

As shown in Figure 42, when Cd is added in activated Sludge System²⁺Afterwards, sludge AUR maximum inhibition and NH₄ ⁺- N removal rate Certain correlation is presented, illustrating to work as has Cd²⁺When participating in reaction, sludge AUR maximum inhibition can reflect out sludge activity Situation of change.But it can be seen from the figure that coordinate points are distributed more loosely in coordinate quadrant, and related coefficient is lower, only It is 0.6621, therefore, using AUR maximum inhibition as judgement heavy metal Cd²⁺It, be to heavy metal when the evaluation index of toxicity Cd²⁺Characteristic carry out overall merit.2 toxicity assessment standard of reference table divides heavy metal Cd²⁺Toxic grade standard, see Table 4 for details.

4 toxic grade standard of table

Toxic grade	Removal rate % (R)	AUR maximum inhibition % [EC (A)]
			It is nontoxic	Greater than 80	Less than EC30
Low toxicity	70~80	EC30~EC40
			Poisoning	50~70	EC40~EC50
Severe	30~50	EC50~EC70
			High poison	0~30	EC70~EC100
Severe toxicity	Equal to 0	Equal to EC100

1.3 Zn²⁺Division to microbial activity toxic effect grade

AUR maximum inhibition and sewage disposal system NH₄ ⁺Linear relationship between-N removal rate is as shown in figure 43.

As shown in Figure 43, when Zn is added in activated Sludge System²⁺Afterwards, sludge AUR maximum inhibition and NH₄ ⁺- N removal rate Good linear relationship is presented, related coefficient reaches 0.8209, and illustrating to work as has Zn²⁺When participating in reaction, AUR activity be can be very good Reflect the situation of change of sludge activity.It therefore, can be using AUR active inhibiting rate as judgement heavy metal Zn²⁺Toxicity is commented Valence index.2 toxicity assessment standard of reference table divides heavy metal Zn²⁺Toxic grade standard, see Table 5 for details.

5 toxic grade standard of table

Toxic grade	Removal rate % (R)	AUR maximum inhibition % [EC (A)]
			It is nontoxic	Greater than 80	Less than EC40
Low toxicity	70~80	EC40~EC60
			Poisoning	50~70	EC60~EC80
Severe	30~50	EC80~EC90
			High poison	0~30	EC90~EC100
Severe toxicity	Equal to 0	Equal to EC100

1.4 Cr⁶⁺Division to microbial activity toxic effect grade

AUR maximum inhibition and sewage disposal system NH₄ ⁺Linear relationship between-N removal rate is as shown in figure 44.

As shown in Figure 44, when Cr is added in activated Sludge System⁶⁺Afterwards, sludge AUR maximum inhibition and NH₄ ⁺- N removal rate Good correlation is presented, for related coefficient relatively up to 0.7947, illustrating to work as has Cr⁶⁺When participating in reaction, sludge AUR activity can be with Preferably reflect the situation of change of sludge activity.Therefore, it can use sludge AUR active inhibiting rate as a judgement huge sum of money Belong to Cr⁶⁺The evaluation index of toxicity.2 toxicity assessment standard of reference table divides heavy metal Cr⁶⁺Toxic grade standard, see Table 6 for details.

6 toxic grade standard of table

Toxic grade	Removal rate % (R)	AUR maximum inhibition % [EC (A)]
			It is nontoxic	Greater than 80	Less than EC50
Low toxicity	70~80	EC50~EC60
			Poisoning	50~70	EC60~EC80
Severe	30~50	EC80~EC90
			High poison	0~30	EC90~EC100
Severe toxicity	Equal to 0	Equal to EC100

1.5 characterization heavy metal toxicities influence the establishment of grade evaluation criterion

In content from heavy metal to microbial activity Effect Evaluation as can be seen that utilizing sludge AUR activity characterization weight When metal influences sewage disposal system toxic effect, maximum inhibition and sewage disposal system NH₄ ⁺Pass between-N removal rate System can have differences because of the type of heavy metal difference, and still, general trend is identical, and inhibits range also and have overlapping Place.Therefore, integration processing is carried out according to content before, can determines that AUR activity influences grade as characterization heavy metal toxicity Evaluation criterion.See Table 7 for details.

7 heavy metal toxicity of table influences grade evaluation criterion

Toxic grade	AUR maximum inhibition % [EC (A)]
		It is nontoxic	Less than EC40
Low toxicity	EC40~EC50
		Poisoning	EC50~EC70
Severe	EC70~EC90
		High poison	EC90~EC100
Severe toxicity	Equal to EC100

1.6 Cu²⁺The recovery Journal of Sex Research that microbial activity is influenced

Currently, existing academic research has confirmed that sludge microbe has certain adaptation energy to heavy metal ion Power, although when heavy metal concentration is more than a certain range the effects of inhibiting, poisoning can be generated to microorganism, certain is slightly raw Object can generate resistance to heavy metal toxicity by own biological function of detoxification and restore activity itself in later period domestication culture And correlation function.This section test uses incremental culture acclimation, by research activated sludge in an a certain concentration huge sum of money Belong to Cu²⁺The situation of change of bioactivity under action condition, the recovery function of being influenced in experimental study on microbial activity are done into one Step research.

This test is tested using the sbr reactor device of stable operation.It will with the artificial sewage that beer is prepared in reactor Its sludge concentration is diluted to 4000mg/L or so, and Ni metal is added into sbr reactor device²⁺Solution makes Cu in reactor²⁺Concentration Respectively reach 1mg/L, 5mg/L, 10mg/L and 25mg/L.Its aeration stirring is run, Dissolved Oxygen concentration Control is in 3~4mg/L In range, pH value is controlled in 7.0~7.5 ranges.Reactor run 5 hours after it is out of service, take 0.6mL mud mixed liquid into Row INT-ETS Activity determination.15min is precipitated, after precipitating, supernatant is taken out, measures its NH₄ ⁺The concentration of-N and COD.Together When, it is placed in the conical flask of 250mL from taking-up mud mixed liquid in reactor and is sufficiently aerated, when mud mixed liquid dissolves Oxygen is inserted into dissolved oxygen electrode when reaching saturation state, guarantee that conical flask has on-line checking dissolved oxygen under conditions of good air-tightness Concentration simultaneously records related data.After measurement, remove conical flask in supernatant, by activated sludge refund in sbr reactor device into Row subsequent experimental.

1.6.1 1mg/L Cu²⁺The domestication result and analysis influenced on microbial activity

1mg/L heavy metal copper ion pair NH₄ ⁺The influence of-N removal rate, COD removal rate is detailed in Figure 45.As seen from the figure, when anti- Answer the Cu that 1mg/L is added in device²⁺Afterwards, COD, NH₄ ⁺The linear downward trend within the first two period of-N removal rate, the 2nd period After two parameter minimize, be reduced to 87.35%, 65.68% from initial 95.85%, 89.28% respectively；Then, NH₄ ⁺- N, COD removal rate are gradually increasing, after the 7th end cycle, COD, NH₄ ⁺- N removal rate restores respectively to 96.75%, 90.12%, and Cu is not added²⁺When removal effect it is similar.Illustrate by 1mg/L Cu²⁺The microflora of influence can be rear It is restored in the culture domestication of phase, the time of recovery is 7 periods.

The active influence of 1mg/L heavy metal copper ion pair INT-ETS is detailed in Figure 46.As seen from the figure, when being added in reactor The Cu of 1mg/L²⁺Afterwards, sludge INT-ETS activity is on a declining curve within first three period, minimizes after the 3rd end cycle, 254.53mg INTF/ (mg TSSh) is reduced to from initial 439.30mg INTF/ (mg TSSh).Then, sludge INT-ETS activity is gradually increasing, and after the 12nd end cycle, sludge INT-ETS activation recovering is not to adding Cu²⁺When water It is flat.Illustrate by 1mg/L Cu²⁺The activated sludge of influence can restore its INT-ETS activity in the culture in later period domestication, i.e., micro- Biosystem has good self-regeneration function.

1mg/L heavy metal copper ion pair SOUR activity, the active influence of AUR are detailed in Figure 47.As seen from the figure, when in reactor The Cu of 1mg/L is added²⁺Afterwards, sludge SOUR activity and AUR activity are on a declining curve, respectively after the 2nd and the 3rd end cycle It minimizes, respectively from initial 64.62mg O₂/(mg MLSS·h)、4.8mg NH₄ ⁺- N/ (g MLSSh) is reduced to 40.68mg O₂/(mg MLSS·h)、2.8mg NH₄ ⁺-N/(g MLSS·h)；Then, sludge SOUR activity and AUR activity by Gradually rise, respectively after the 7th, the 8th end cycle, two activation recoverings are not to adding Cu²⁺When level.Illustrate by 1mg/ L Cu²⁺The activated sludge of influence can make SOUR activity and AUR activity be restored in the culture in later period domestication.

1.6.2 5mg/L Cu²⁺The domestication result and analysis influenced on microbial activity

5mg/L heavy metal copper ion pair NH₄ ⁺The influence of-N removal rate, COD removal rate is detailed in Figure 48.As seen from the figure, when anti- Answer the Cu that 5mg/L is added in device²⁺Afterwards, COD, NH₄ ⁺The linear downward trend within preceding 4 periods of-N removal rate, the 4th period After two parameter minimize, be reduced to 80.45%, 30.22% from initial 94.35%, 85.68% respectively；Then, COD、NH₄ ⁺- N removal rate is gradually increasing, and is restored after the 9th and the 14th end cycle to initial removal effect respectively.But by To 5mg/L Cu²⁺Long when time needed for the microflora recovery of influence is than adding 1mg/L, microflora has preferably Self-regeneration function.

5mg/L heavy metal copper ion pair INT-ETS activity influence is detailed in Figure 49.As seen from the figure, when being added in reactor The Cu of 5mg/L²⁺Afterwards, sludge INT-ETS activity is on a declining curve within preceding 4 periods, minimizes after the 4th end cycle, 206.75mg INTF/ (mg TSSh) is reduced to from initial 425.68mg INTF/ (mg TSSh).Then, sludge INT-ETS activity is gradually increasing, and after the 10th end cycle, sludge INT-ETS activation recovering is not to adding Cu²⁺When water It is flat, restore required time and restores COD, NH₄ ⁺It is almost the same the time required to-N removal rate, but compare Cu²⁺Concentration is wanted when being 1mg/L It is long.

5mg/L heavy metal copper ion pair SOUR activity, the active influence of AUR are detailed in Figure 50.As seen from the figure, when in reactor The Cu of 5mg/L is added²⁺Afterwards, sludge SOUR activity and AUR activity are on a declining curve, minimize after the 3rd end cycle, point Not from initial 60.54mg O₂/(mg MLSS·h)、4.6mg NH₄ ⁺- N/ (g MLSSh) is reduced to 24.63mg O₂/(mg MLSS·h)、0.8mg NH₄ ⁺-N/(g MLSS·h)；Then, sludge SOUR activity and AUR activity are gradually increasing, respectively the 6th After a, the 9th end cycle, two activation recoverings are not to adding Cu²⁺When level.System restores SOUR activity and AUR activity institute It is suitable when the time needed is with 1mg/L, illustrate Cu²⁺There there is no substantially recovery active to system SOUR and AUR when concentration rises to 5mg/L It influences.

1.6.3 10mg/L Cu²⁺The domestication result and analysis influenced on microbial activity

10mg/L heavy metal copper ion pair NH₄ ⁺The influence of-N removal rate, COD removal rate is detailed in Figure 51.As seen from the figure, when anti- Answer the Cu that 10mg/L is added in device²⁺Afterwards, COD, NH₄ ⁺The linear downward trend within preceding 2 periods of-N removal rate, the 2nd period After two parameter minimize, be reduced to 65.85%, 15.46% from initial 93.45%, 89.28% respectively；Then, COD、NH₄ ⁺- N removal rate is gradually increasing, and is restored after the 22nd and the 28th end cycle to initial removal effect respectively.Explanation By 10mg/L Cu²⁺The microflora of influence needs the long period that could restore, and microflora also has certain self Repair function.

10mg/L heavy metal copper ion pair INT-ETS activity influence is detailed in Figure 52.As seen from the figure, when being added in reactor The Cu of 10mg/L²⁺Afterwards, sludge INT-ETS activity is on a declining curve within preceding 3 periods, and the 3rd end cycle minimizes, from Initial 420.74mg INTF/ (mg TSSh) is reduced to 182.08mg INTF/ (mg TSSh).Then, sludge INT- ETS activity is gradually increasing, and after the 14th end cycle, sludge INT-ETS activation recovering is not to adding Cu²⁺When level.It says It is bright by 10mg/L Cu²⁺Influence, activated sludge can the culture in later period domestication in restore its INT-ETS activity, but need It is long when time is than low concentration.

10mg/L heavy metal copper ion pair SOUR activity, the active influence of AUR are detailed in Figure 53.As seen from the figure, work as reactor The interior Cu that 10mg/L is added²⁺Afterwards, sludge SOUR activity and AUR activity are on a declining curve, respectively in the 3rd the 2nd end cycle After minimize, respectively from initial 58.96mg O₂/(mg MLSS·h)、4.5mg NH₄ ⁺- N/ (g MLSSh) is reduced to 15.65mg O₂/(mg MLSS·h)、0.6mg NH₄ ⁺-N/(g MLSS·h)；Then, sludge SOUR activity and AUR activity by Gradually rise, respectively after the 12nd, the 17th end cycle, two activation recoverings are not to adding Cu²⁺When level.Illustrate by 10mg/L Cu²⁺The activated sludge of influence can restore its related activity in the culture in later period domestication.

1.6.4 25mg/L Cu²⁺The domestication result and analysis influenced on microbial activity

25mg/L heavy metal copper ion pair NH₄ ⁺The influence of-N removal rate, COD removal rate is detailed in Figure 54.As seen from the figure, when anti- Answer the Cu that 25mg/L is added in device²⁺Afterwards, COD, NH₄ ⁺- N removal rate is on a declining curve within preceding nine periods, the 9th period knot Two parameter minimizes after beam, is reduced to 38.45%, 5.45% from initial 92.05%, 88.56% respectively；Then, COD, NH4+-N removal rate is on the rise, but amplitude is smaller.COD, NH since the 40th period₄ ⁺- N removal rate is always in a certain numerical value It floats in range.This illustrates higher concentration Cu²⁺Serious destruction is caused to microflora, this destroy has certain continuity Property, it is difficult to make it restore to the state before not being damaged using microorganism itself repair function.

25mg/L heavy metal copper ion pair INT-ETS activity influence is detailed in Figure 55.As the Cu that 25mg/L is added in reactor²⁺ Afterwards, sludge INT-ETS activity is on a declining curve within preceding 7 periods, and reacts more obvious, after the 1st end cycle just Have fallen to 110.62mg INTF/ (mg TSSh).It is minimized after 7th end cycle, from initial 415.25mg INTF/ (mg TSSh) is reduced to 108.82mg INTF/ (mg TSSh).Then, sludge INT-ETS activity is gradually increasing, After the 20th end cycle, the left and right sludge INT-ETS activation recovering 380.54mg INTF/ (mg TSSh), lower than not throwing Add Cu²⁺When level.Illustrate by 25mg/L Cu²⁺A degree of destruction is caused to activated sludge structure, activity is rear Although having recovery in the culture domestication of phase, level when being extremely difficult to not be damaged, this can also illustrate microflora certainly My repair function is effective in certain damage envelope.

25mg/L heavy metal copper ion pair SOUR activity, the active influence of AUR are detailed in Figure 56.As seen from the figure, work as reactor The interior Cu that 25mg/L is added²⁺Afterwards, sludge SOUR and AUR activity are on a declining curve within preceding 9 periods, and react more bright It is aobvious, 20.02mg O is just dropped to respectively after the 1st end cycle₂/(mg MLSS·h)、0.9mg NH₄ ⁺-N/(g MLSS·h).Minimized after 9th end cycle, then, sludge SOUR activity and AUR activity are restored, but amplitude compared with It is slow, and terminating below not adding Cu²⁺When level.Illustrate to add more than after a certain concentration, activated sludge structure is by one Determine the destruction of degree, although activity is improved in the culture domestication in later period, be difficult to be restored to level when not being damaged, This can also illustrate that microflora self-regeneration function is effective in certain damage envelope.

1.7 this part brief summaries

The present invention uses simulated domestic wastewater for process object, is tried using the activated sludge tamed in laboratory It tests, high spot reviews four kinds of copper, cadmium, zinc, chromium single heavy metals are living to denitrification dephosphorization system microorganism under varying environment factor Property influence and Analysis on Mechanism, on this basis, introduce sludge INT-ETS activity, sludge SOUR, sludge AUR, microbial activity Inhibiting rate and EC50, system thinking difference heavy metal, to the affecting laws of sludge activity, judge a huge sum of money under the conditions of various concentration Belong to the sensitivity to the toxic effect evaluation index of bioactivity, establish toxicity assessment classification standard and microbial activity influence it is extensive Renaturation research obtains following Main Conclusions：

The above embodiment is a preferred embodiment of the present invention, but embodiments of the present invention are not by above-described embodiment Limitation, other any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present invention, It should be equivalent substitute mode, be included within the scope of the present invention.

Claims

1. the evaluation method of heavy metal toxicity in a kind of Biological Nutrient Removal system, it is characterised in that including walking as follows Suddenly：

(1) dirt is selected to activated sludge INT-ETS activity, SOUR, AUR toxic effect evaluation index sensitivity level according to heavy metal Mud AUR activity is as bioactivity toxic effect evaluation index；

2. the evaluation method of heavy metal toxicity in Biological Nutrient Removal system according to claim 1, special Sign is：

The evaluation criterion that the heavy metal toxicity influences grade is；

3. the evaluation method of heavy metal toxicity in Biological Nutrient Removal system according to claim 1 or 2, It is characterized in that：

The heavy metal is at least one of copper, cadmium, zinc and chromium.

4. the evaluation method of heavy metal toxicity in Biological Nutrient Removal system according to claim 1 or 2, It is characterized in that：

In the activated sludge, microorganism concn is 2000~3000mg/L, and COD load is 200~400mg/L, dissolved oxygen For 0~1.5mg/L, pH=6~8.0.

5. the evaluation method of heavy metal toxicity in Biological Nutrient Removal system according to claim 1 or 2, It is characterized in that：

Need to control effluent COD concentration within 50mg/L, NH₄ ⁺- N concentration is within 8mg/L.