Background technology
Cape Town, RSA university (the Modified University of Cape Town) technology of the innovation that nineteen ninety occurs is called for short MUCT technology, is one of technology that is used for the earliest biological carbon and phosphorous removal simultaneously, also is the flow process of the widespread use in present various countries.
MUCT technology is provided with anaerobic zone, two oxygen-starved areas, aerobic zone and settling regions in turn, has active sludge in each district.Technology is provided with three return lines, is respectively: the muddy water mixed solution from first oxygen-starved area to anaerobic zone refluxes, and the muddy water mixed solution from aerobic zone to second oxygen-starved area refluxes and the mud from the settling region to first oxygen-starved area refluxes.Sewage at first enters into anaerobic zone.In anaerobic zone, a large amount of polyP bacterias in the active sludge absorb the lipid acid in the sewage, and decompose intravital poly-phosphorus and become deliquescent phosphoric acid salt, are discharged in the sewage.Because the effusive mud mixture of anaerobic zone constantly flow into first oxygen-starved area, cause the interior a large amount of mud of anaerobic zone to enter into the oxygen-starved area.In order to guarantee activated sludge concentration stable in the anaerobic zone, set up muddy water mixed solution to reflux from first oxygen-starved area to anaerobic zone.First oxygen-starved area is when receiving from the anaerobic zone muddy water mixed solution, and the mud that also receives from the settling region refluxes.Second oxygen-starved area is accepted to get nitrification liquid from aerobic zone and is refluxed, and has a large amount of nitrate and orthophosphoric acid salt like this in second oxygen-starved area.The nitrate that polyP bacteria utilization in the active sludge exists enters into the poly-phosphorus of formation in the cell as the orthophosphoric acid salt that the electron acceptor(EA) excess absorbs in the water, and nitrate is reduced into nitrogen, thereby nitrogen and phosphorus in the water are removed.In addition, in the oxygen-starved area, also exist different oxygen denitrifying bacteria.Denitrifying bacteria can utilize that remaining organism becomes nitrogen as carbon source denitrification nitrate in the water.Enter into aerobic zone from the effusive mixed solution in second oxygen-starved area.The function of aerobic zone has two: the one, and the ammonia nitrogen in the sewage is by nitrated one-tenth nitrate; Another is that organism remaining in the sewage is oxidized.Muddy water mixed solution enters into the settling region in the aerobic zone, realizes mud-water separation in the settling region.Supernatant liquor is used as the water outlet discharging after the final processing.The part excess sludge is collected to be done further to dispose.
MUCT technology successfully guarantees the anaerobic state of anaerobic zone, thereby has improved the dephosphorization ability of system.But along with the rapid progress of water technology and improving constantly of water treatment requirement, the shortcoming of this technology also manifests gradually.Thereby influence it to a great extent in application in engineering.
At first, the technology power consumption is bigger.Because traditional MUCT technology denitrification process still adopts traditional complete nitrification, this means in nitrifying process and will expend a large amount of oxygen.With respect to short distance nitration, the nitrated oxygen consumption of complete nitrification increases 25%.The oxygen consumption of complete nitrification causes significantly increasing of its cost of water treatment.
Secondly, speed of response is not high.An effective means that reduces initial investment and running cost is to improve pollutant removal speed, thereby reduces the hydraulic detention time and the useful volume of reaction tank.In traditional MUCT technology, the complete nitrification that nitrated employing is traditional.With respect to short distance nitration, the complete nitrification reactor volume has increased by 30~40%.Because Nitrosomas is shorter than Nitromonas generation time, mud is also short age.So being controlled at the nitrous acid stage can improve microorganism concn and nitration reaction speed, shorten the nitration reaction time.In addition, since MUCT technology itself remove when relying on denitrification dephosphorization to be implemented in the triangular web to a great extent pollutents such as organism, nitrogen, phosphorus.After nitrated finishing, realize denitrification dephosphorization as electron acceptor(EA) with nitrate.But,, will further improve denitrification dephosphorization speed if after realizing short distance nitration, realize denitrification dephosphorization as electron acceptor(EA) with nitrite.The raising of speed of response will reduce reactor volume, save initial cost.
Short distance nitration technology is also referred to as nitrite type biological nitration technology, is the water treatment new technology that occurs at present, and its ultimate principle is controlled at nitrifying process the nitrite stage exactly, stops NO
2-Further nitrated.Therefore, how to realize in traditional MUCT technology short distance nitration and with the denitrification dephosphorization of nitrite as electron acceptor(EA), reduce to handle energy consumption, improve speed of reaction, the output that guarantees maximum treatment effect and energy consumption is than the direction that is traditional MUCT technological innovation.
Do not obtain far-reaching denitrification if it should be noted that short distance nitration, will contain a large amount of nitrous nitrate in the water outlet.Nitrite has very big toxic action as unsettled oxidizing substance.It is carcinogenic, can combine with red blood corpuscle rapidly, consumes dissolved oxygen, brings out nutrient laden.Based on such reason, the realization short distance nitration must be noted that and farthest prevents to contain in the water outlet high nitrous acid, it is produced murder by poisoning to environment drop to minimum.
Summary of the invention
The object of the present invention is to provide the processing method and the device of nitrogen phosphorus and organic pollutant in a kind of biological removal sewage, guarantee short distance nitration and utilize nitrite under best separately envrionment conditions, significantly to take place simultaneously, improve nitrated and suction phosphorus speed as the denitrification dephosphorization energy of electron acceptor(EA).Under the prerequisite that guarantees effluent quality and safety, increase substantially processing efficiency, save operation energy consumption and expense.
A kind ofly can realize short distance nitration simultaneously and with the device of nitrite, promptly improved MUCT process unit as the denitrifying phosphorus removal technique of electron acceptor(EA);
Anaerobic reactor 1, first anoxic reacter 2, second anoxic reacter 3, aerobic reactor and the precipitation reactor 7 of Lian Jieing in turn, be respectively equipped with whipping appts 8 in anaerobic reactor, two anoxic reacters, first anoxic reacter, 2 water sides are connected to the feed-water end of anaerobism return line 13 with anaerobic reactor 1 with anoxic by reflux pump 12, and the lower end of precipitation reactor 7 is connected with first anoxic reacter, 2 feed-water ends with reflux pump 12 by mud return line road 15;
It is characterized in that: aerobic reactor is divided into two, be provided with deoxidation reactor 5 between two aerobic reactors, establish whipping appts 8 in the deoxidation reactor 5, second anoxic reacter 3 connects first aerobic reactor 4, first aerobic reactor 4 connects deoxidation reactor 5, deoxidation reactor 5 connects second best oxygen reactor 6, second best oxygen reactor 6 connects precipitation reactor 7, in first aerobic reactor 4 and the second best oxygen reactor 6 aerator 11 is set respectively, aerator 11 gas flow controller 10 by separately is connected with external air pump 9, and the water side of deoxidation reactor 5 is connected with the feed-water end of reflux pump 12 with second anoxic reacter 3 by nitrification liquid return line 14.
A kind ofly can realize short distance nitration simultaneously and with the denitrifying phosphorus removal technique of nitrite as electron acceptor(EA), promptly improved MUCT technology operating procedure is:
(1) inoculation is arrived in each reactor from the active sludge of municipal wastewater treatment plant second pond.The processing parameter of adjusting in each reactor is tamed active sludge, makes polyP bacteria, denitrifying phosphorus removing bacteria, Nitrosomas and common heterotrophic bacterium raised growth, and becomes the advantage kind of treatment system;
(2) raw waste water is injected anaerobic reactor 1, and the whipping appts 8 in the startup anaerobic reactor 1, make raw waste water carry out anaerobism under the effect of stirring and put phosphorus reaction, after hydraulic detention time was 1.2~2.0 hours, anaerobic reactor 1 went out water mixed liquid and enters into first anoxic reacter 2;
(3) after anaerobic reactor 1 goes out water mixed liquid and enters into first anoxic reacter 2, start the whipping appts 8 in first anoxic reacter 2, under the effect of stirring, carry out anoxic and inhale phosphorus reaction, supernatant liquor water outlet in first anoxic reacter 2 enters second anoxic reacter 3, mixed solution is back to anaerobic reactor 1 through reflux pump 12 and anoxic to anaerobism return line 13, and reflux ratio is 1~2;
(4) after liquid enters into second anoxic reacter 3, start the agitator 8 in second anoxic reacter 3, under the effect of stirring, carry out further anoxic and inhale phosphorus reaction, simultaneously, nitrate is reduced into nitrogen, realize the purpose of sewage water denitrification, 3 water outlets of second anoxic reacter enter first aerobic reactor 4;
(5) after liquid enters into first aerobic reactor 4, start aerator 11 and the gas flow controller 10 that is connected with aerator 11 in first aerobic reactor 4, carry out aerated reaction, remove remaining organism, the oxidation ammonia nitrogen, first aerobic reactor, 4 inner control dissolved oxygen concentrations are below 1mg/L, control low dissolved oxygen and can realize short distance nitration, ammonia nitrogen is oxidized to nitrite, after hydraulic detention time is 2~5 hours, the long hydraulic detention time of control guarantees that the ammonia nitrogen oxidation is complete, and water outlet enters deoxidation reactor 5;
(6) after liquid enters deoxidation reactor 5 deoxidation reactors, start the whipping appts 8 in the deoxidation reactor 5, under the effect of stirring, remove the dissolved oxygen in 4 water outlets of first aerobic reactor, after 10~20 minutes, supernatant liquor enters second best oxygen reactor 6, mixed solution is back to second anoxic reacter 3 through nitrification liquid return line 14 and reflux pump 12, and reflux ratio is 1~2;
(7) after liquid enters second best oxygen reactor 6, start aerator 11 and the gas flow controller 10 that is connected with aerator 11 in the second best oxygen reactor 6, carry out further aerated reaction, unemployed nitrite-oxidizing is become nitrate, the dissolved oxygen concentration of liquid in second best oxygen reactor 6 is between 2.0~2.5mg/L, hydraulic detention time 1~2 hour, high dissolved oxygen levels guarantees that nitrous acid is oxidized to nitrate rapidly, prevent to contain in the water outlet nitrous acid environment is produced toxic action, water outlet enters precipitation reactor 7;
(8) liquid carries out mud-water separation after entering precipitation reactor 7, and the time is 0.5~1 hour, and supernatant liquor effluxes after the mud-water separation, and mud enters into first anoxic reacter 2 through mud return line road 15 and reflux pump 12 backflows, and reflux ratio is 0.5~1.0.
The present invention has the following advantages:
(1) aerobic reactor with original MUCT technical process carries out classification, has created the optimal environmental condition that helps Nitromonas and Nitrosomas two big monoid microorganism existence respectively;
(2) behind first aerobic reactor, deoxidation reactor is set, reduces to the dissolved oxygen concentration in the first aerobic reactor water outlet minimum.Then the mixed-liquor return in the deoxidation reactor is carried out anoxic to second anoxic reacter and inhale phosphorus and denitrification;
(3) adopt isolating, the controlled aerating system of two covers that the fractionated aerobic reactor is implemented the control of different aeration rates, have different dissolved oxygen concentration conditions in two reactors thereby be implemented in.Simultaneously, two aerobic reactors have different hydraulic detention time (HRT);
(4) first aerobic reactors have long HRT and low dissolved axygen concentration guarantees that fully ammonia is all oxidized, keep below the dissolved oxygen concentration of 1mg/l simultaneously.In first aerobic reactor, utilize low dissolved axygen can guarantee that to the sorting pressure of Nitromonas and Nitrosomas short distance nitration farthest takes place, and can be further energy-conservation.Long HRT guarantee ammonia nitrogen almost all in first aerobic reactor oxidation complete;
(5) the short residence time and the higher dissolved oxygen concentration of second best oxygen reactor inner control.In second best oxygen reactor, high dissolved oxygen concentration is set, give nitrous acid oxidation bacterium advantage, promote it that unemployed nitrite of rest parts is oxidized into nitrate apace, do not contain nitrite in the water outlet and make.Because the residue nitrous acid concentration is less, its hydraulic detention time is shorter, reduces aeration expending energy.
Technology has realized farthest with the denitrification dephosphorization of nitrite as electron acceptor(EA).Realize far-reaching short distance nitration at first aerobic reactor, can keep high nitrous acid accumulation rate.At follow-up deoxidation reactor the phegma of high nitrite content directly is sent to anoxic reacter, has guaranteed that its anoxic inhales phosphorus and the nitrite of maximum is arranged as electron acceptor(EA).It is oxidized that the unemployed nitrite mixed solution of remainder enters into follow-up second best oxygen reactor continuation, and it is minimum that water outlet Central Asia nitrate content is dropped to, and prevented the issuable further harm of nitrite.
The invention has the beneficial effects as follows:
Adopt improved MUCT art breading sanitary sewage, the nitrosification and the control of nitrated stage that take place in turn in the nitrifying process are occurred in the two-stage aerobic reactor, and realized with the denitrification dephosphorization of nitrite as electron acceptor(EA).Compare with traditional MUCT technology, beneficial effect of the present invention is presented as:
1, realized short distance nitration, reduced by 25% oxygen consumption, thereby reduced cost of sewage disposal.In the first aerobic reactor inner control low dissolved axygen concentration,, thereby guarantee that short distance nitration farthest takes place by the selection of low dissolved selective pressure realization to ammonia oxidation bacteria.
2, improve nitrification and denitrification dephosphorization speed, reduced the volume of reactor.The nitration reaction time has been shortened in the realization of short distance nitration, has improved rate of nitrification.In addition, realization as the electron acceptor(EA) denitrification dephosphorization, further improves denitrification dephosphorization speed with nitrite.The speed of reaction that improves can dwindle 30~40% with reactor volume.The raising of speed of response has reduced initial cost and running cost.
3, setting up of deoxidation pond prevents that effectively dissolved oxygen guarantees the real anoxic condition in oxygen-starved area to the disadvantageous effect of denitrification generation in the Aerobic Pond internal reflux liquid.The mixed solution that contains a large amount of nitrite concentrations enters in the follow-up deoxidation reactor, carries out brief stay, is back in the anoxic reacter after removing dissolved oxygen.Prevent that dissolved oxygen from entering in the anoxic reacter, influence denitrification and anoxic and inhale phosphorus.
The safety of the stable and water quality treatment of 4, handling.Technology has guaranteed the optimum regime of anaerobism, anoxic and aerobic environment effectively, thereby promotes various functional microorganisms to bring into play physiological metabolism in the growing environment that needs separately, thereby makes treatment effect good and stable.In addition, poison and insecurity because nitrite has environment, the remaining nitrite of part further is oxidized to nitrate in second best oxygen reactor, make the toxicity of water outlet drop to minimum.Guaranteed the environmental safety of effluent quality.
Embodiment
Improved MUCT technology operating procedure is referring to accompanying drawing 1.This processing method is the precedence according to dephosphorization and nitration reaction in traditional MUCT denitrification dephosphorization system, and nitrosification and nitrated being controlled at respectively in two reaction response devices that the aerobic nitrification process takes place are in turn carried out, and forms the two-stage aerobic nitration processes.For the influence that prevents that dissolved oxygen from inhaling phosphorus to anoxic, behind first aerobic reactor, set up deoxidation reactor, the dissolved oxygen in the phegma drops to minimum.Simultaneously, the backflow of aerobic nitrification liquid comes from deoxidation reactor.The device that adopts is can realize short distance nitration simultaneously and with the denitrifying phosphorus removal technique device of nitrite as electron acceptor(EA) in the technical solution of the present invention.
The operating procedure of improved MUCT technology is:
(1) raw waste water enters anaerobic reactor 1 and carries out anaerobism and put phosphorus.Sludge concentration is controlled at 2000~3000mg/L, and hydraulic detention time is 1.2~2.0 hours;
Mixed solution in (2) first anoxic reacters 2 is back to anaerobic reactor 1 by return line 13.It mainly acts on is the sludge concentration that guarantees anaerobic zone, and reflux ratio is 1~2;
(3) by mud return line road 16, returned sluge enters into first anoxic reacter 2 from precipitation reactor 7, and reflux ratio is 0.5~1.0;
(4) anaerobic reactor 1 goes out water mixed liquid and enters into first anoxic reacter 2.The denitrification phosphorus-collecting bacterium utilizes the nitrate that contains in the mud that refluxes from precipitation reactor 7 to carry out anoxic suction phosphorus.Because the content of the nitrate that contains in the mud in the precipitation reactor 7 is less relatively, anoxic is inhaled phosphorus and can be utilized nitrate to inhale phosphorus as electron acceptor(EA) fully, and is simultaneously that the nitrate denitrification is complete;
(5) by nitrification liquid return line 14, nitrification liquid is back to second anoxic reacter 3 from deoxidation reactor 5, and it mainly acts on is to guarantee that competent nitrite enters in the anoxic reacter 3, and reflux ratio is 1~2.
(6) mixed solution enters in second anoxic reacter 3, carries out significant denitrifying phosphorus uptake at second anoxic reacter 3.Most nitrogen is removed at this reactor, and a large amount of phosphoric acid salt of anaerobism release simultaneously are by excessive absorption.
(7) in first aerobic reactor 4, remaining organism is removed, and ammonia nitrogen is all oxidized.This reactor control dissolved oxygen concentration is below 1mg/L, and hydraulic detention time is 2~5 hours.According to the Oland principle, in low dissolved oxygen environment, ammonia oxidation bacteria obtains the ability of oxygen greater than nitrous acid oxidation bacterium, so the condition of growth of advantage is provided for ammonia oxidation bacteria in the environment of low dissolved axygen, guarantees the nitrous acid accumulation rate more than 85%;
(8) after deoxidation reactor 5 is provided in a side of first aerobic reactor 4, have 10~20 minutes short residence times.Its main purpose is the dissolved oxygen of farthest removing in the first aerobic reactor water outlet, avoids the influence to denitrifying phosphorus uptake of dissolved oxygen that aerobic nitrification liquid contains in refluxing;
(9) the main effect of second best oxygen reactor 6 is that unemployed nitrite-oxidizing is become nitrate, prevents to contain in the water outlet nitrite environment is produced toxic action.Second best oxygen reactor 6 hydraulic detention times 1~2 hour, dissolved oxygen concentration is controlled at 2.0~2.5mg/L, by extended aeration, guarantees that the residue nitrite is oxidized into nitrate;
(10) aerobic reactor 6 water outlets enter into precipitation reactor 7 and carry out mud-water separation, and supernatant liquor effluxes.0.5~1 hour 7 residence time of precipitation reactor.
The device that adopts is can realize short distance nitration simultaneously and with the denitrifying phosphorus removal technique device of nitrite as electron acceptor(EA) in the technical solution of the present invention.The MUCT device is referring to accompanying drawing 1: anaerobic reactor 1, first anoxic reacter 2 is connected in turn with second anoxic reacter 3, second anoxic reacter 3 connects first aerobic reactor 4, first aerobic reactor 4 connects deoxidation reactor 5, deoxidation reactor 5 connects second best oxygen reactor 6, second best oxygen reactor 6 connects precipitation reactor 7, anaerobic reactor 1, be respectively equipped with whipping appts 8 in two anoxic reacters 2 and the deoxidation reactor 5, first anoxic reacter, 2 water sides are connected with anoxic to the feed-water end of anaerobism return line 13 with anaerobic reactor 1 by reflux pump 12, in first aerobic reactor 4 and the second best oxygen reactor 6 aerator 11 is set respectively, aerator 11 is connected with external air pump 9 by gas flow controller 10, the water side of deoxidation reactor 5 is connected with the feed-water end of reflux pump 12 with second anoxic reacter 2 by nitrification liquid return line 14, and the lower end of precipitation reactor 7 is connected with first anoxic reacter, 2 feed-water ends with reflux pump 12 by mud return line road 15;
The invention is characterized in: the aerobic reactor of original MUCT technical process is carried out classification, set up two-stage aerobic reaction response device.Each reaction response device is provided with independently gas meter and aerating apparatus, two aeration reactors is realized the control of different dissolved oxygen concentrations.Behind the first aerobic reaction reactor, deoxidation reactor is set, the dissolved oxygen concentration in the nitrification liquid is dropped to minimum, prevent from that nitrification liquid from refluxing dissolved oxygen is brought into anoxic reacter influences denitrifying phosphorus uptake.Nitrification liquid refluxes and is back to anoxic reacter from the deoxidation reactor water outlet, guarantees the electron acceptor(EA) of a large amount of nitrite as denitrifying phosphorus uptake.
Adopt the general sanitary sewage of processing of improved MUCT technology, its effluent quality can reach more than the one-level category-B standard in State Standard of the People's Republic of China's urban wastewater treatment firm pollutant emission standard (GB 18918-2002).And can energy efficient, reduce running cost and initial investment.