Summary of the invention
To the problems referred to above of prior art, the inventor has accomplished the present invention through concentrating on studies.Promptly the present invention proposes and a kind ofly can reduce processing cost effectively, simplify technological process greatly, and can handle various paper wastes, the particularly treatment process of high loading middle-stage wastewater.
Specifically, the invention provides a kind of technological process of treating papermaking method, comprising: filter, flocculation sediment, biochemical treatment and advanced treatment step is characterized in that, QA is adopted in biochemical treatment
2The O treatment process.
Wherein, described QA
2The O treatment process comprises complex reaction aeration, the multistage AO aeration of time-delay and pulse water distribution upwelling anaerobic reaction.
In addition, treatment process of the present invention also comprises handling the advanced treatment step of waste water.
In addition, the said micro-filtration that is filtered into, the order number of filter screen is from the 80-120 order.
Also comprise in addition QA
2The mud that O produces carries out sludge dewatering treatment.
2O mainly comprises three sections of A1, A2, O; But bigger with traditional A2O process distinction, because of its A1, A2, three sections independent settings of O, and every section is respectively A1 (complex reaction aeration tank), A2 (pulse water distribution upwelling anaerobic reactor), O (the multistage AO aeration tank of delaying time); This technology has the removal ability of pollutents such as extremely strong SS, COD, BOD; The circulation of traditional A2O mud all runs through whole technology, and the Aerobic Pond mixed solution circulates in A2 section and O section in a large number, and main purpose is the realization denitrogenation dephosphorizing.
1, technical process contrast
QA2O technology: see Fig. 2 for details
Tradition A2O technology: see Fig. 3 for details
Can find out that by above-mentioned two artworks QA2O technology and traditional A2O process distinction are bigger; Mud is circulation in three sections of A1, A2, O in traditional A2O technology; Settling tank is not established in the centre, and the mixed solution circulation is arranged in that A2, O two are intersegmental, and A1 is that anaerobism A2 is that the oxygen O that holds concurrently is aerobic in these three sections.The A1 section is main with the oxygen bacterium of holding concurrently in QA2O technology, met physical reaction again simultaneously, and this section is provided with settling tank separately; The independently mud recycle system is arranged, and the A2 section is main with obligatory anaerobic bacteria, is anaerobic technique completely; The independently mixed solution recycle system is arranged, do not rely on A1 and O section mud and reflux, the O section is main with aerobic bacteria then; Alternately oxygen supply through aerator realizes that the series connection of a plurality of oxygen enrichment anoxic sections is multistage AO, and the biological pond of selecting is set before the O section, to reach the purpose of optimizing bacterial classification.
This technology mainly contains five effects greatly: remove SS, denitrogenation, dephosphorization, raising biodegradability, degraded COD and BOD.
(1) is main in the A1 section to remove SS, the nitration denitrification reaction takes place simultaneously, realize denitrification dephosphorization function (seeing complex reaction aeration tank part for details)
(2) be main mainly in the A2 section, play the effect that certain larger molecular organics chain rupture is decomposed into small organic molecule again simultaneously, improved the clearance of follow-up O section, and realize the release of phosphorus with anaerobic digestion.(seeing acoustic streaming anaerobic reactor part on the pulse water distribution for details).
(3) then bring into play the advantage of aerobic bacteria fully in the O section, and realize that simultaneously multistage AO alternately, makes mikrobe have more activity, to reach higher removal efficient.Under the time-delay underload, move for a long time in addition and generated a large amount of aerobic particle muds.
The complex reaction aeration tank
The complex reaction aeration tank is the A1 section in this technology.
The selection of waste water treatment process is directly connected to effect, running cost and the total investment of engineering of wastewater treatment, so the suitable waste water treatment process of careful selection is the key of this engineering.The selection of waste water treatment process should be taken all factors into consideration according to multiple factors such as design Inlet and outlet water water quality, degree of treatment requirement, floor space, project scales, and various technologies all have its applicable elements, should fit actual conditions and decides.
China's pulp and paper industry output has occupied the third place in the world, and paper technology upgrades day by day.The paper-making industrial waste water quantity discharged is big, and is seriously polluted, and ecological damage property is big, is puzzlement countries in the world paper industry and the hot issue of environmental protection organization and the emphasis of research for many years always.My company furthers investigate paper waste from putting into practice the angle of practical applications, has developed the feasible suitable process program of a cover.
The waste water of papermaking enterprise discharging mainly contains middle-stage wastewater and paper machine white water.Plain boiled water can be handled all or part of slurrying workshop section that is back in back; Middle section water is mainly from the waste water that produces in pulping, screening, the floatation process; Its staple is tiny suspension fiber, papermaking filler, waste paper impurity and a small amount of pectin, wax, carbohydrate, and all kinds of organic and mineral compound that adds in the paper process.The characteristics of waste water are that SS and COD are all higher; And non-solubility COD is higher, accounts for more than 60%; When SS is removed, but non-dissolubility COD simultaneously also major part be lowered.The ratio of B/C in the paper waste is generally not high, but most BOD and solubility COD also want the applying biological method to remove, and is more hard to manage.
And confirm to adopt combined chemistry reaction aeration tank-precipitator method (QA at last through test in place repeatedly
2The A of O technology
1Section) as pre-treating technology, can obtain good ss, cod treatment effect.
One, this technology is the novel technique that biological absorption-degrading activity mud method combines with the materialization flocculation reaction; Be in the conventional activated sludge method, (the AB method is the absorption biological degradation method for two sections activated sludge processes, materialization flocculence, AB methods; Form by A section B section two portions; The A section is main with bacterium absorption propagation, belongs to the high loading biochemical processing process, and the B section can be traditional aerobic biological treatment process) the basis on the sewage treatment process that grows up.This technology belongs to the high loading activated sludge process, and sewage is introduced into the A1 section of high loading, and then gets into the A2 section of low anaerobism load, is getting into the series operation of ultra-low load O section.A1 section mud has very strong adsorptive power and good sedimentation function.The A1 section is that flocculation adsorption with bacterium is main to organic removal, with materialization flocculation adsorption as strengthening and replenishing.A1 segment process sludge loading height, mud age and hydraulic detention time are short, so the investment of A segment process and working cost are low, the enhanced primary that belongs to the high loading Sludge System is handled.This technology has following characteristics in paper waste is handled:
(1) capacity of resisting impact load is strong, and water quality, the water yield of intaking had huge self-regulated ability, can not make the treatment system paralysis because of the rapid variation of water quality and quantity, stop transport, and loses processing power; When coming water water-quality COD, SS by normal variation water quality to 2 times, water outlet still can keep higher clearance even higher clearance, if in time adjust operating parameter even can keep effluent quality constant, or slightly raises.Strong like this anti impulsion load is for the steady running of whole integrated technique provides assurance.
(2) mud has very strong adsorptive power and good sedimentation function, and process sludge load height reaches as high as 7kg/kgmlss.d, mud age and the water conservancy residence time short (30min-60min), and investment and working cost are low, clearance high (40%-65%).
(3) used technology has bigger biochemical reaction impellent, has stronger adsorption-flocculation and decomposing oxidation to improve the biodegradability ability to the pollution substance of difficult for biological degradation in the paper waste; Because this pond is to be main with the oxygen bacterium of holding concurrently with aerobic bacteria, especially double oxygen effect makes waste water B:C behind this pond can improve 2%-5%.
(4) transfer efficiency of oxygen is higher, saves aeration energy consumption; Move owing to adopt under the LDO condition, this has just improved gas-liquid mass transfer efficient greatly, uses coefficient of oxygen utilization to improve greatly, can use dissolved oxygen efficiency to reach more than 40%, and dynamicefficiency reaches more than 4.
(5) technical process is simple, and structures are few, simple and convenient operation and maintenance;
(6) treatment effect is stable;
(7) biochemistry is combined with materialization, obtain higher removal efficient and more stable effect of settling.
Commercially available aerator commonly used can be adopted in the complex reaction aeration tank, is conspicuous to those skilled in the art for equipments choice, need not to make creative work.
A large amount of mikrobe (bacterium) is generally all surviving in the waste water; These bacterial growth reproduction speeds are very fast, can realize a generation cycle in general 20 minutes, that is to say one day and can breed for 72 generations; And the general vitality of these bacteriums is more intense, and is not high to environmental requirement.Can utilize the excess sludge of aerobic activated sludge to improve concentration and the population density of mikrobe such as bacterium and primary metazoan in the aeration tank in addition, to reach high efficiency operation.
Three, processing parameter
After waste water entered into the complex reaction aeration tank, this pond main control parameters was following:
Temperature T=20-35 ℃
Hydraulic detention time HTR=30min-60min
Sludge concentration MLSS=3000-10000mg/L
Dissolved oxygen DO=0.1-1.0
30 fens SV of settling ratio
Sludge index SVI=150-350
Sludge age SRT=20-40min
Reflux ratio R=40%-200%
Through behind the aeration, get into the settling tank precipitate and separate, for example between aeration tank and settling tank, adding in right amount according to separating effect, PAM regulates.Before getting into the complex reaction aeration tank, for example can add PAC commonly used.In the operational process of settling tank, must control sludge interface, surface load and reflux ratio.Belong to the scope of conventional design for these parameter control, those of ordinary skills can carry out suitable adjusting according to the particular case of waste water.Usually, sludge interface is suitable to be controlled at more than 3 meters, and surface load should be lower than 1.2m
2.h, reflux ratio is controlled according to sludge interface and excess sludge output.Can improve the service efficiency of settling tank like this, improve sludge loading and also increased removal efficient simultaneously.
This technology is compound physical-chemical reaction and biochemical reaction makes the flco density, adsorptive power etc. of physical reaction obtain great enhancing, and the settleability that has promoted biochemical action is arranged simultaneously, makes it be easier to mud-water separation, is that water outlet is more clear.
Pulse water distribution upwelling anaerobic reactor
This reactor drum is the A2 section in the QA2O technology, is main with anaerobic reaction mainly, and sewage is in this section, and main hydrolytic reactions, fermentative acidification react, produce acetic acidreaction and methanation reaction.
One, this reactor drum principal feature has:
1, without triphase separator.This is one of maximum difference of this anaerobic reactor and conventional reactors, through bigger diameter/height ratio (5: 1), has reduced the flow velocity of waste water, thereby has reached the purpose of solid-liquid separation.
2, adopt the pulse water distribution system; Through syphonic effect with having stored in the water distributor 3～5 minutes A1 section water outlet rushes at the pond with very fast flow velocity in the short period of time (several seconds to tens seconds) at the bottom of; Upwards dash the sludge blanket at the bottom of the pond and to be suspended state; Thereby make the muddy water uniform mixing in the pond, guaranteed the efficient of anaerobic reaction.
3, be particularly useful for (but being not limited only to) wheat straw chemical pulp middle-stage wastewater.Mierocrystalline cellulose in this waste water, semicellulose, polysaccharide, reducing sugar, treated starch, part lignin and the verivate thereof etc. of joining in the coating waste-water there is good specific aim; Well brought into play acidication these macromole size degradations have been become small molecules, for follow-up aerobic treatment creates conditions.
4, anerobes is granule sludge and floc sludge.Because diameter is too small, flow velocity is high mostly for the tradition anaerobism, and it is serious to make floc sludge run off; And be main to cultivate the prilling anaerobic sludge, this reactor drum then can make the coexistence of granule sludge and floc sludge, acts on simultaneously; To reach higher removal effect, also improved the removal ability of ss simultaneously.
5, single pond processing power is big, owing to adopt big blade diameter length ratio, makes single pond processing power improve greatly.
This reactor drum mainly be with the organism in the waste water under the acting in conjunction of a large amount of mikrobes; Be converted into methane, carbonic acid gas, water, hydrogen sulfide and ammonia; Different anerobess, the oxygen bacterium of holding concurrently interact, condition each other in this process, are very complicated coenosiss.The process of its degradation of organic substances can be divided into four sections:
1, the macromolecular organism of hydrolysis stage is decomposed into small molecules in this stage by the bacterium extracellular enzyme, is chain rupture, and micromolecular hydrolysate is easy to dissolving.For example: the Mierocrystalline cellulose in this stage paper waste is cellobiose, glucose etc. by cellulase hydrolysis; Pectin and degradation product thereof be by the pectin enzymic hydrolysis, and then better degraded by bacterium.
2, souring stage is converted into voltaile fatty acid, alcohols, carbonic acid gas, hydrogen, ammonia, hydrogen sulfide etc. by dissolved organic matter such as disaccharides, the glucose etc. that hydrolysis section generates under the effect of fermenting bacterial.
3, produce the acetate stage under the effect of acetogen, the product of souring stage is converted into acetate, hydrogen, carbonic acid gas and other new cell etc.
4, produce methane phase under the effect of methanogen, acetate, hydrogen, carbonic acid, formic acid, methyl alcohol etc. are converted into methane, carbonic acid gas, new cell etc.Thereby reach the purpose of degradation of organic substances.
After waste water was handled through the A1 section, the proportioning through adjustment C: N: P for example was adjusted to 200: 5: 1, flows automatically to the A2 section, gets into the for example about 300m of volume
3The pulse water distribution jar, the pulse water distribution device water distribution cycle is 8 minutes, the pulse water distribution device was accomplished a water-filling water distribution process in promptly per 8 minutes; Waste water is sent into the anaerobic sludge layer uniformly through the water distributor of cloth at the bottom of the pond, under the effect of obligatory anaerobic bacteria, DeRs such as organic hydrolysis, fermentation, product acetate, methanation takes place; The general stop 16 hours all accomplished these reactions, and sewage progressively rises in reactor drum; For example accomplish mud-water separation in 2.5-1.0 rice apart from rising pipe at last, sludge settling continues to fall after rise to sludge blanket, and continues to rise through the gas of sewage behind the anaerobic reaction and anaerobism generation; At the rising pipe place; Sewage overflow goes out reactor drum, and aerogenesis (methane, hydrogen sulfide, carbonic acid gas etc.) gathers gas collection district, top, pond, and is collected into the biogas cabinet at this top gas collection tube place, district.
The main technical details of this system is following:
1, the water yield: single pond maximum amount of water Q
2, influent load: COD
3, water distribution: effect and water distribution that acid is produced in hydrolysis have much relations; This section adopts the high-efficiency pulse water distribution system; It is with having stored in the water distributor 3～7 minutes A1 section water outlet rushes at the pond with very fast flow velocity in the short period of time (several seconds to tens seconds) at the bottom of through syphonic effect; Upwards dashed the sludge blanket at the bottom of the pond and to be suspended state, thereby made the muddy water uniform mixing in the pond.
4, temperature: this parameter directly affects growth velocity and activity, the physico-chemical property etc. of bacterium, tackles this and carries out strictness control.Have a liking for the warm type mikrobe because the mikrobe in this system belongs to, the temperature of system is controlled at 20～39 ℃.
5, pH: because hydrolysis bacterium and acid-producing bacteria have flexibility in a big way to pH, methanogen then requires relatively harsher to pH, and the pH of system of therefore controlling well influence system for anaerobic treatment to move one of fine or not important factor.Through test of many times, this value is controlled between the 6.5-7.5.
6, sludge concentration: require to have very high sludge concentration in the normal postrun hydrolysis acidification pool, the general controlled 6000-25000mg/L that is made as, the best is 18000mg/L
7, hydraulic detention time: 16h.
8, the sludge retention time in the reactor drum: 15-60d, preferred 45d.
9, sludge volume index: 50-150, preferred 70
10, system sludge internal recycle amount: confirm according to the water yield and water distribution situation, can be controlled between the 0-40%.
11, O section return sludge ratio: need a large amount of O section mud to tame during debugging, need add certain anaerobic species simultaneously.Can add on a small quantity during normal the operation,, increase sludge concentration, improve the anerobes rate of growth to improve clearance.
12, nutritive substance:, therefore must maintain good bacterial growth state because the anaerobic treatment process of waste water is accomplished by bacterium fully.Except the carbon source of necessity, nitrogenous source, also need replenish necessary nutritive element in the paper waste.The characteristics of actual waste water are arranged and determine it to add ratio, the COD in operational process of assurance system: N: P is 150～500: 5: 1.Preferred 200: 5: 1.Those of ordinary skills can suitably adjust above-mentioned parameter according to the particular case of waste water, and these adjustment are conspicuous to those skilled in the art, need not to make creative work.
The multistage AO aeration tank explanation of delaying time
The multistage AO aeration tank of delaying time is the O section in the QA2O technology, waste water in this section, mainly be with aerobic be main, realize the series connection of a plurality of oxygen enrichment anoxic sections the nitrification and denitrification reaction taking place through the alternately oxygen supply of aerator.
One, principal feature:
1, more reasonable to the utilization of oxygen
Multistage A/O process using is interrupted aeration, and active sludge is in " aerobic-anoxic " alternative environment.That active sludge is in is this " hungry full " alternative state can be brought into play self potential, under good oxygen condition, accelerates the degradation speed to pollutent, and the raising processing efficiency especially improves the utilization ratio to oxygen.
2, more effective to the removal of NH4-N
Repeatedly nitrated-anti-nitration reaction stack, to the removal effect of NH4-N be superior to tradition single nitrated-anti-nitration reaction.-denitrification technology (clearance of NH4-N generally 60%～70%) nitrated with tradition compared, and multistage A/O technology has shortened nitrated-anti-nitration reaction time, has increased progression; Through experiment proof: after the controlling reaction time, each cycle can obtain 20%～30% NH4-N clearance, can obtain the clearance greater than 85% through for example 8 cycles.
3, effectively avoided the generation of sludge bulking phenomenon
Sludge bulking the most directly shows as sludge index SVI and raises.Cause the reason of sludge bulking a lot (like the variation of water temperature and quality etc.), with regard to the high sludge loading in aeration tank itself, high sludge concentration, single operation scheme all when water quality worsens suddenly sludge bulking takes place easily.Because multistage A/O process using is interrupted aeration, mixed solution is through the alternating action of aerobic zone and oxygen-starved area repeatedly, and whole process using hangs down sludge loading, can effectively avoid the generation of sludge bulking phenomenon.
4, surplus sludge volume is few
This process sludge quantity of reflux is big, sludge concentration high (sludge concentration of design aeration tank is 3000-4000mg/L), and living weight is big.The residence time of mud in the aeration tank is long, and pollutants in waste water can be by fully degraded.
Waste water from the A2 section in the QA2O technology at first gets into biological selector, through preaeration, carries out the domestication of dominant bacteria.Get into the aeration zone then; Under the aeration zone was in aerobic condition, aerobic cenobium (nitrobacteria, nitrite bacteria etc.) was preponderated, and making itrogenous organic substance is ammonia by bacterial degradation; Under the effect of nitrite bacteria, further be converted into nitrite then, be converted into nitrate salt through the nitrobacteria effect again; Nitrate salt enters into the district that stops the supple of gas or steam, and facultative cenobium is preponderated gradually, under the effect of facultative different oxygen bacterium; Utilize or part utilizes that original organism carbon source is electron donor in the waste water; Substitute molecular oxygen with nitrate salt and make electron acceptor(EA), decompose organic matter, simultaneously; Nitrogen in the nitrate salt is reduced to gaseous nitrogen (N, NO2 etc.); When entering into the aeration zone again, aerobic cenobium is preponderated again and ability strengthens; In like manner enter into when stopping the supple of gas or steam the district, facultative cenobium is preponderated again and ability strengthens; The carrying out of going round and beginning again, nutritive substance reduce and the cenobium quality and quantity is all increasing, and reach " balance between supply and demand " state very soon; Be " supply-less-than-demand " state afterwards, nutritive substance is by thoroughly clean decomposition, and the material of some difficult degradations is also decomposed by the mud cenobium of excellent performance at this moment.
Sewage is through biological selector, carry out the optimization of bacterial classification after, get into the multistage AO of time-delay aeration tank, under the effect of nitrifier, nitrococcus, facultative heterotrophic bacteria, the nitrification and denitrification reaction is taking place, thereby degradation of organic substances.The main technical details of this system has:
1, mud organic loading: the mud organic loading in the native system is about 0.05-0.1kgBOD5/kg (MLSS); Preferred 0.05; This has also demonstrated fully characteristics---the underload activated sludge process of multistage A/O; It has made full use of mikrobe and the metabolic whole process of mikrobe that mud provides, and pollutants in waste water is fully degraded.
2, mixed solution sludge concentration: in real work, adopt this index to measure the quantity of active sludge microorganism indirectly, the operation of system.Usually be controlled between the 3000-4000mg/L preferred 3500mg/L.
3, hydraulic detention time: native system belongs to extended aeration, and general hydraulic detention time is between 50-65 hour, and is best between the 52-57.The so long residence time is that good treatment effect provides the prerequisite assurance, makes pollutent obtain the more purifying treatment of the degree of depth.Make the excess sludge very stable corruption that is difficult for that becomes because nitration reaction has taken place, excess sludge has obvious minimizing simultaneously.
4, sludge index (SVI): this parameter has reflected the loosening degree of mud, is to judge that sludge settling concentrates a parameter commonly used of performance, in daily administration, can judge whether to take place sludge bulking through this parameter, and the control sludge volume.According to service experience, this parameter generally is controlled between the 150-200, and sludge settling property is bad when too high, the sludge dewatering weak effect, though it is good to cross low settling property, but absorption property is poor.
5, reflux ratio: this system sludge quantity of reflux is big, adopts 100% to reflux.Surplus sludge volume is little, because action of microorganisms makes that mud can be not smelly, the processing of mud is also than being easier to simultaneously.
6, dissolved oxygen: the demand of the DO of different bacterial classifications is different, and to this system of multistage A/O, we control DO between 0.2-2.0, preferred 0.5-1.0, thus realize the decarburization denitrogenation better.
7, sludge age: the sludge age of system is long more, and the nitrogen and phosphorus content in the mud is just low more, organic matter removal thorough more.Generally be controlled at 15-25 days, 18-22 days best.
8, nutritive element: carbon, nitrogen, phosphorus are the important elements that constitutes the sludge microbe body, and they provide the energy for the existence of bacterium, and native system is regulated three's ratio at any time according to the variation of water quality, and generally with COD: N: P was controlled at 100: 5: 1.
Waste water through after this system handles can be by reducing in the 100mg/L about former water COD5000mg/L.
In filtration step of the present invention, can adopt filtering technique conventional in the prior art, so that remove silt particle, fiber, part xylogen, pigment or the like, when removing a large amount of solid substances (SS), can also reclaim slurry.
Preferably, adopt rotary Microfilter to filter, select 80-120 purpose steel mesh or nylon wire for use, the slurry that recovery obtains preferably is concentrated into 2% (weight) and returns pulping system, and waste water is after filtering controlled its SS less than 800mg/L.
Waste water after filtering still contains silt, for reducing the reuse cost, improves quality of reused water, guarantees the normal operation of follow-up equipment, preferably waste water is carried out desanding and handles.Can adopt desanding means commonly used in the prior art, this is conspicuous for those of ordinary skills.
Usually adopt settling pit to carry out sand setting and handle, the sediment outflow at intermittence is carried out in the bottom, and supernatant carries out step of flocculation precipitation.
It in the present invention, has no particular limits, can adopt flocculation agent commonly used in the prior art, as long as can reach the purpose of flocculation sediment for the flocculation agent that is adopted.For example, can adopt ferro-aluminum composite salt salt flocculation agent well known in the prior art.
In the present invention,, can also add coagulant aids in order to reach better flocculation sediment effect, same, have no particular limits for the use of coagulant aids, as long as can reaching, it helps the purpose of coagulating.For example can adopt SEPIGEL 305 coagulant aids commonly used or the like.Its consumption is had no particular limits, and those of ordinary skills can carry out appropriate selection as required.
Through method of wastewater treatment of the present invention, the reclamation rate of waste water reaches more than 60%.