CN103922461B - A kind of method monitoring Sewage Biological Treatment oxygen uptake rate and control aeration rate - Google Patents

Abstract

The present invention relates to a kind of method monitoring Sewage Biological Treatment oxygen uptake rate and control aeration rate.The present invention measures under the conditions of different air mass flows q, temperature and setting sludge concentration, the oxygen transfer ratio K of aeration aerating_La(d^‑1) and saturated dissolved oxygen concentration mg/L, obtain oxygen transfer ratio K_LA and air demand q, temperature T, at known set oxygen transfer ratio K_La(d^‑1) and dissolved oxygen concentration under conditions of, by the dissolved oxygen change curve in the matching period, utilized the oxygen uptake rate of a upper period, as the oxygen uptake rate that next stage is possible, the minimum aeration rate q of required subsequent period, within the ensuing period, air capacity q, dissolved oxygen change curve, obtains this period oxygen uptake rate.The defect such as instant invention overcomes that the equipment investment that prior art exists is big, structure is complicated or test frequency is low.On the premise of the present invention does not increase extra auxiliary reactor, dissolved oxygen probe and sewage transport equipment, just can monitor OUR continuously merely with dissolved oxygen probe.

Description

A kind of method monitoring Sewage Biological Treatment oxygen uptake rate and control aeration rate

Technical field

The invention belongs to process monitoring and the control technology of a kind of Sewage Biological Treatment, be exactly a kind of prison specifically Survey Sewage Biological Treatment oxygen uptake rate and the method controlling aeration rate.

Background technology

The method of Sewage Biological Treatment is also activated sludge process, since 20 beginning of the century activated sludge process inventions, The always main method of countries in the world sanitary sewage disposal.It is to utilize active microorganism, is providing Under conditions of dissolved oxygen, the Organic substance in sewage and ammonia nitrogen etc. are aoxidized, reach the purpose removed.Dissolved oxygen Supply usually relies on aerator aeration and completes.Aeration is the main energy consumption in sewage disposal process, generally can account for To the energy consumption of more than the 50% of biological wastewater treatment process.Therefore, on the premise of ensureing treatment effect, find The method reducing aeration in sewage treatment amount, is the important means reducing sewage disposal energy consumption.One of them is important Monitoring index just determines that the oxygen uptake rate (OUR) of biology.

Before the present invention makes, biological OUR be reaction biological wastewater treatment process contaminant degradation speed, One important indicator of activity of activated sludge, traditional mensuration OUR method includes interval and two kinds of sides of METHOD FOR CONTINUOUS DETERMINATION Method.Batch process is after aeration stops, and the dissolved oxygen (DO) in record sewage-treating reactor is in certain time The value of interior reduction, both are divided by and obtain OUR, and it is relatively low that this method measures frequency, it is impossible to as a kind of continuous print The method of on-line monitoring, and measured value is less than normal；Continuity method is that to arrange small-sized pair on main reactor side anti- Answering device (or other glass container), active sludge intermixture is successively inputted to auxiliary reactor from main reactor In, then be back to main reactor, the dissolved oxygen concentration in the major and minor reactor of Simultaneous Determination, its concentration difference and The ratio of the auxiliary reactor time of staying (HRT) is OUR, and this method needs in main reactor and side reaction Dissolved oxygen probe is all set in device, and needs sewage backflow equipment, structure complexity, add equipment investment, And that the method measures is the OUR in auxiliary reactor, can not reflect OUR in main reactor completely.

Summary of the invention

The purpose of the present invention is that and overcomes drawbacks described above, develops one monitoring Sewage Biological Treatment oxygen uptake rate With the method controlling aeration rate.

The technical scheme is that

A kind of method monitoring Sewage Biological Treatment oxygen uptake rate and control aeration rate, its technical characteristics exists In carrying out in accordance with the following steps:

(1) measuring under the conditions of different air mass flows q, temperature and setting sludge concentration, the oxygen transfer of aeration aerating is Number K_La(d^-1) and saturated dissolved oxygen concentration mg/L, obtain oxygen transfer ratio K_LA and air demand q, temperature T Quantitative relation formula:

KLa=aqb^T-20 (1)

(2) equation below is passed through:

$\frac{\mathrm{dDO}}{\mathrm{dt}}=\mathrm{KLa}(O_{\mathrm{Sat}}-\mathrm{DO})+\mathrm{OUR}---(2-1)$

$\frac{\mathrm{dDO}}{\mathrm{dt}}=\mathrm{KLa}(O_{\mathrm{Sat}}-\mathrm{DO})+\mathrm{OUR}-\frac{\mathrm{DO}}{\mathrm{HRT}}---(2-2)$

At known set oxygen transfer ratio K_La(d^-1) and saturation under dissolved oxygen concentration under conditions of, by intend Close the dissolved oxygen change curve in certain period, obtain the oxygen uptake rate in this period, for sequence batch reactor with, Use previous formula (2 1), for flow reactor, use later formula (2 2)；

(3) oxygen uptake rate of a upper period was utilized, as the oxygen uptake rate that next stage is possible, also with step Suddenly the formula that (2) are inner, obtains the dissolved oxygen concentration reaching to set, the minimum aeration of required subsequent period Amount q；

(4) within the ensuing period, being applied with air capacity q that step (3) is tried to achieve in reactor, measuring should Dissolved oxygen change curve in period, the method utilizing step (2), obtain the actual oxygen of this period and absorb Speed, repeat the above steps (1), (2), (3), (4), until reaction terminates.

The mensuration of the dissolved oxygen concentration of described invention and the mensuration of oxygen uptake rate are all complete in same main reactor Become.

The OUR of the mensuration of described invention is the oxygen uptake rate value in actual sewage-treating reactor.

Described invention utilizes the seriality of oxygen uptake rate, the control to sewage disposal process aeration rate.

The mensuration of the oxygen uptake rate of described invention, and the control of aeration rate is all that formula described in 2 completes in steps 's.

The method have the advantages that

1) present invention is not on the premise of increasing extra auxiliary reactor, dissolved oxygen probe and sewage transport equipment, OUR can be measured with continuous print；

2) the OUR value in the OUR that the present invention measures is actual sewage-treating reactor, more closing to reality Situation；

3) present invention can be also used for the control of sewage disposal process aeration rate, controls effect and is better than traditional PID Control, it is possible to accomplish according to oxygen uptake rate aeration, it is to avoid excess aeration.

4) present invention need not arrange auxiliary reactor, molten merely be arranged in bioreactor for disposing polluted water Solve oxygen probe, it is possible to continuous print monitoring OUR.Traditional Sewage Biological Treatment aeration control typically uses can Programmable controller (PLC), utilizes PID control principle, sets suitable pid parameter, in making Aeration tank Dissolved oxygen keep set concentration.Owing to sewage composition and flow are sooner or later and seasonal change, Suitable pid parameter of a certain period is generally difficult to obtain in the another one period preferably control effect.The present invention Utilize the OUR of monitoring, aeration rate can be controlled accurately, it is ensured that in reactor, dissolved oxygen concentration is in setting value.

5) present invention could apply to continuously or in sequence batch reactor with.

Accompanying drawing explanation

Fig. 1 present system schematic flow sheet.

Fig. 2 present invention calibrates different air mass flow oxygen transfer ratio figure, and wherein (A) is for estimating endogenous exhaling Oxygen uptake transfer rate figure, (B) is for measuring oxygen transfer ratio figure figure.

Fig. 3 sequence of the present invention batch reactor with implementation result figure, wherein (C) is air mass flow figure, and (D) is Dissolved oxygen figure, (E) is the oxygen uptake rate figure of monitoring.

Fig. 4 flow reactor of the present invention implementation result figure, wherein (F) is air mass flow figure, and (G) is Dissolved oxygen figure, (H) is the oxygen uptake rate figure of monitoring.

In figure, each label represents that corresponding component names is as follows:

Feed liquor case 1, reactor 2, dissolved oxygen probe 3, air supply system 4, data acquistion and control system 5, Computer 6, agitator 7, intake pump 8, temperature probe 9.

Detailed description of the invention

Below in conjunction with instantiation, illustrate that the present invention is in typical sequence criticizes (SBR) and continuous activated sludge process Detailed description of the invention.

Sewage in feed liquor case 1 is in intake pump 8 is transferred to reactor 2, and agitator 7 is arranged on reactor In 2, the mix and blend under low aeration rate, dissolved oxygen probe 5 is in being arranged on reactor 2 and is submerged in In liquid, temperature probe 9 is also mounted in reactor 2 and floods in a liquid, and air supply system 4 extend into instead Answer in device 2 in liquid；Dissolve probe 3, temperature probe 9 measure data through data acquistion and control system 5, It is sent to computer 6, and data acquistion and control system 5 output order controls intake pump 8, air supply system 4.

The most ready batch (SBR) and continuous activated sludge process illustrate its concrete enforcement.

Embodiment 1: sequence criticizes (SBR) activated sludge process

It specifically comprises the following steps that

Step one: measure different air mass flows q (0,30,40,60,80,120L/h), temperature becomes Under the conditions of change, the oxygen transfer ratio K of aeration aerating_La(d^-1) and saturated dissolved oxygen concentration Osat (mg/L), Obtain oxygen transfer ratio K_LA and air demand q, the quantitative relation formula of temperature T.

Measure oxygen transfer ratio K_LThe quantitative relation formula method of a and air demand q is as follows:

1) by activated sludge continuous aeration more than 12 hours in reactor so that mud is in endogenous respiration state, Keep sludge concentration stable during mensuration, thus avoid sludge concentration to K_LThe impact of a and Osat；

2) stop aeration 15 minutes, utilize computer data acquisition system according to every 10 seconds frequency notes once Record dissolved oxygen concentration, utilizes the mode of curve matching to calculate endogenous oxygen breathing rate (OUR_endMg/ (L × d)), As shown in Fig. 2 (A)；

3) set certain air mass flow needing to measure, start aeration 45 minutes, according to every 10 seconds frequencies once Rate record dissolved oxygen concentration and temperature, after aeration terminates, carry out curve fitting to dissolved oxygen concentration by below equation:

$\frac{\mathrm{dDO}}{\mathrm{dt}}=\mathrm{KLa}(O_{\mathrm{Sat}}-\mathrm{DO})+{\mathrm{OUR}}_{\mathrm{end}}---\left(3\right)$

Wherein DO is the dissolved oxygen concentration of record, OUR_endMeasure for this step 2.By curve matching (Fig. 2 (B) shown in), it is possible to draw oxygen transfer ratio K_La(d^-1) and saturated dissolved oxygen concentration Osat (mg/L)；

4) repeat 2 in this step, 3 liang of steps, measure three K altogether_LA and Osat, averages as measurement Value；

5) 2 in this step are repeated, 3,4, measure the K under the conditions of other air demand q_LA and Osat；

6) oxygen transfer ratio K is drawn_LThe quantitative relation formula of a and air demand q is as follows:

KLa=4.3042q1.017^T-20 (4)

Wherein a, b are coefficient, q be air mass flow (L/h), T be temperature (degree Celsius)

Step 2: 5 minute period (T of On-line Estimation₁OUR in).Air mass flow q is provided to reactor₁=23L/h, Within following 5 minute period, utilize computer data acquisition system, according to every 10 seconds frequencies once, The dissolved oxygen concentration of record, after record end, utilizes formula (3 1), matching gained dissolved oxygen concentration, estimates Calculate the oxygen uptake rate (hereinafter referred to as OUR) in this 5 minute period.

Wherein KLa value can obtain according to formula (4) conversion, and Osat selectes according to temperature T, in formula (2 1), Only OUR is unknown, by matching gained dissolved oxygen concentration curve, it is possible to obtain the OUR=19.2 in this period mg O₂/ (L*h)；

Step 3: calculate (T in next 5 minute period₂) air demand.Utilize the OUR (19.2 of step 2 gained mg O₂/ (L*h)), as the OUR of next 5 minute period, utilize formula (2 1), calculate required Minimum KLa value so that at the dissolved oxygen concentration of this 5 minute period Mo close to setting value (DO_set=1.0mg/L). Required air demand q is pushed away again by formula (4) is counter₂=9.7L/h, by computer control system by air demand q₂Instruction air supply system is implemented；

Step 4: repeat step 2, three, calculation interval (T₂Actual OUR value in) and next one 5 minutes Interior (T₃) air demand, repeatedly perform step 2, three, four, until reaction terminate.Permissible by Fig. 3 (C) Seeing, the present invention can control aeration rate with continuous print so that dissolved oxygen maintains setting value 1.0mg/L (Fig. 3 (D)), and continuous print monitoring OUR (Fig. 3 (E)).

Embodiment 2: activated sludge process continuously

It specifically comprises the following steps that

Step one: the reactor in transformation SBR case study on implementation so that it is continuum micromeehanics, changes flow of inlet water, The time of staying (HRT) making flow reactor is 8 hours, and arranges the precipitation that the time of staying is 4 hours Pond, clarifier sludge reflux ratio is 2.Flow of inlet water, on the basis of the 8 hourly average time of staying, is carried out continuously Change, with the fluctuation of sewage quantity in simulating.Oxygen transfer ratio K in flow reactor_LA and air demand q Relation identical with sbr reactor device, see formula (4).

Step 2: 5 minute period (T of On-line Estimation₁OUR in).Air mass flow q is provided to reactor₁=10L/h, Within following 5 minute period, utilize computer data acquisition system, according to every 10 seconds frequencies once, The dissolved oxygen concentration of record, after record end, utilizes formula (2 2), matching gained dissolved oxygen concentration, estimates Calculate the OUR in this 5 minute period.

Wherein KLa value can obtain according to formula (4) conversion, and Osat selectes according to temperature T, in formula (2 2), Only OUR is unknown, by matching gained dissolved oxygen concentration curve, it is possible to obtain the OUR=10.2 in this period mg O₂/ (L*h)；

Step 3: calculate (T in next 5 minute period₂) air demand.Utilize the OUR of step 2 gained, make For the OUR of next 5 minute period, utilize formula (2 2), calculate required minimum KLa value so that At the dissolved oxygen concentration of this 5 minute period Mo close to setting value (DO_set=1.0mg/L).Anti-by formula (4) again Push away required air demand q₂=4.1L/h, by computer control system by air demand q₂Refer to that modern air supply system is implemented；

Step 4: repeat step 2, three, calculation interval (T₂Actual OUR value in) and next one 5 minutes Interior (T₃) air demand, repeatedly perform step 2, three, four, until reaction terminate.Shown in Fig. 4, this Bright can with continuous print regulation and control air demand q (Fig. 4 (F)) so that dissolved oxygen is maintained at 1.0mg/L (Fig. 4 (G)), And continuous print monitoring OUR (Fig. 4 (H)).

Claims (5)

1. monitor Sewage Biological Treatment oxygen uptake rate and the method controlling aeration rate for one kind, it is characterised in that according to such as Lower step is carried out:

(1) measure under the conditions of different aeration rate q (L/h), temperature T (DEG C) and setting sludge concentration, obtain K_La Quantitative relation formula with q, T:

K_LA=aqb^T-20

Wherein, K_LA is oxygen transfer ratio K_La-d^-1；A and b is coefficient, dimensionless unit；

(2) equation below is passed through:

$\frac{dDO}{dt}=K_{L}a(O_{Sat}-DO)+OUR$

$\frac{dDO}{dt}=K_{L}a(O_{Sat}-DO)+OUR-\frac{DO}{HRT}$

Wherein DO is dissolved oxygen concentration (mg/L)；T is the time (d)；O_SatFor saturated dissolved oxygen concentration (mg/L)；OUR For oxygen uptake rate (mgO₂/(L*d))；HRT is hydraulic detention time (d)；

At the K set_LA and O_SatUnder under the conditions of, by the dissolved oxygen change curve in the matching period, obtain this time OUR in Duan, for sequence batch reactor with, uses previous formula, for flow reactor, uses later Formula；

(3) OUR of a upper period was utilized, as the OUR that next stage is possible, also with the public affairs that step (2) is inner Formula, obtains the dissolved oxygen concentration reaching to set, the aeration rate q of required subsequent period；

(4) within the ensuing period, applying the aeration rate q tried to achieve by step (3) in reactor, measuring should Dissolved oxygen change curve in period, the method utilizing step (2), obtain the actual OUR of this period, Repeat the above steps (1), (2), (3), (4), until reaction terminates.

A kind of side monitoring Sewage Biological Treatment oxygen uptake rate and controlling aeration rate the most according to claim 1 Method, it is characterised in that the mensuration of dissolved oxygen concentration and the mensuration of oxygen uptake rate are all in same main reactor Complete.

A kind of side monitoring Sewage Biological Treatment oxygen uptake rate and controlling aeration rate the most according to claim 1 Method, it is characterised in that the OUR of mensuration is the oxygen uptake rate value in actual sewage-treating reactor.

A kind of side monitoring Sewage Biological Treatment oxygen uptake rate and controlling aeration rate the most according to claim 1 Method, it is characterised in that utilize the seriality of oxygen uptake rate, the control to sewage disposal process aeration rate.

A kind of side monitoring Sewage Biological Treatment oxygen uptake rate and controlling aeration rate the most according to claim 1 Method, it is characterised in that utilize the mensuration of oxygen uptake rate, and the control of aeration rate is all public affairs described in 2 in steps Formula completes.