CN108862581A - A kind of device and method that AO biomembrane+sludge fermentation coupling denitrification realizes sewage deep denitrogenation synchronous sludge decrement - Google Patents

Abstract

A device and method for coupling denitrification with AO biofilm + sludge fermentation to realize deep denitrification of sewage and simultaneous sludge reduction, which belongs to the technical field of sewage biological treatment. The system mainly includes a raw water tank, an AO biofilm reactor, an intermediate water tank, Sludge storage tank, sludge fermentation coupling denitrification reactor; sewage and returned nitrification liquid enter the anoxic zone of the AO biofilm reactor for partial denitrification and anaerobic ammonium oxidation reaction denitrification; the mixed solution continues to flow into the aerobic zone to generate Nitrification reaction, its effluent enters the intermediate water tank, part of it is returned to the front end of the anoxic zone, and the other part enters the sludge fermentation coupling denitrification reactor; the remaining sludge of the urban sewage treatment plant stored in the sludge storage tank enters the sludge fermentation coupling In the denitrification reactor, sludge fermentation occurs to realize sludge reduction, and the energy generated by sludge fermentation is used for denitrification deep denitrification. The invention saves energy and energy consumption, and is suitable for deep denitrification of sewage with low C/N ratio and high nitrogen load.

Description

A kind of AO biofilm + sludge fermentation coupling denitrification realizes deep denitrification of sewage synchronously Apparatus and method for sludge reduction

technical field

The invention relates to a device and method for coupling denitrification with AO biofilm + sludge fermentation to realize deep denitrification of sewage and simultaneous sludge reduction, belonging to the technical field of sewage biological treatment. Sewage denitrification + anaerobic ammonium oxidation reaction denitrification is realized in the AO biofilm reactor, and the effluent nitrification liquid enters the sludge fermentation coupled denitrification reactor for further deep denitrification. The mud is reduced, the energy generated by fermentation can be utilized, and the NH4 ⁺ produced can be removed, which serves multiple purposes. This technology is suitable for advanced treatment of sewage with low C/N ratio and high nitrogen load.

Background technique

my country's urban domestic sewage treatment is facing many challenges, among which the removal of total nitrogen and the treatment of excess sludge are particularly severe. The eutrophication of water bodies is becoming more and more serious, and the state is also strengthening the control of nitrogen emissions. In the "Pollutant Discharge Standards for Urban Sewage Treatment Plants" (GB18918-2002) promulgated in 2002, the first-level A standard for nitrogen is less than 5mg/L for ammonia nitrogen. Total nitrogen is less than 15mg/L. At present, exogenous denitrification is still the main way to remove nitrogen, but the C/N ratio of urban domestic sewage in my country is generally low, which cannot provide sufficient C sources, which seriously restricts the effect of nitrogen removal. Many sewage treatment plants can only meet nitrogen discharge standards by adding external C sources to strengthen denitrification, which is not only costly, but also generates more excess sludge. The treatment of excess sludge is also a big problem. For a typical urban sewage treatment plant, the cost of sludge treatment accounts for about 40% of the total cost. In order to solve these problems, research and development of economical and efficient sewage biological treatment denitrification new technology has become the key.

The biofilm method is a biological treatment method for degrading nutrients in sewage by adding fillers to make microorganisms grow and proliferate on the surface of the fillers to form activated sludge biofilms. Compared with the activated sludge method, it is convenient to manage and the output of residual sludge is very low. Moreover, the biofilm method is conducive to the growth of anammox bacteria and nitrifying bacteria with a long generation cycle and slow value-added speed, and is conducive to the realization of enhanced denitrification methods such as anammox and simultaneous nitrification and denitrification.

Sludge fermentation is a common method to treat excess sludge, but it will release organic matter and ammonia nitrogen while reducing the amount, causing secondary pollution. Combining sludge fermentation and denitrification in one reactor, the organic matter generated by fermentation can be used as a carbon source for denitrification and denitrification, and the ammonia nitrogen produced by fermentation can also pass through anaerobic ammonia oxidation together with the nitrous produced during denitrification. Removal does not affect the water quality of the effluent.

Contents of the invention

The invention organically combines new technologies such as biofilm, denitrification coupling anaerobic ammonium oxidation, sludge fermentation coupling denitrification, etc. Compared with the traditional activated sludge process, the AO biofilm reactor has a lower residual sludge output, and there is an anoxic zone The anaerobic ammonium oxidation reaction makes the nitrogen removal efficiency higher. The effluent from the AO reactor can be used as the source of nitrate nitrogen for the sludge fermentation coupled denitrification reactor. The denitrification reaction will continue to denitrify, and at the same time, it can treat the external excess sludge. It is an economical and efficient treatment method that serves multiple purposes.

In order to achieve the above object, the present invention provides a device for coupling denitrification with AO biofilm + sludge fermentation to realize deep denitrification of sewage and simultaneous sludge reduction, which is characterized in that it includes a raw water tank (1), an AO biofilm reactor ( 2), raw water inlet pump (2.1), stirring device Ⅰ (2.2), suspended packing Ⅰ (2.3), suspended packing Ⅱ (2.4), nitrification liquid return pump (2.5), aerator head (2.6), air compressor ( 2.7), gas flow meter (2.8), intermediate water tank (3), sludge storage tank (4), sludge fermentation coupled denitrification reactor (5), nitrifying liquid inlet pump (5.1), sludge inlet pump (5.2), Stirring device II (5.3), temperature-controlled heating rod (5.4), temperature on-line monitoring controller (5.5), drain valve (5.6), mud discharge valve (5.7);

The raw water tank (1) is connected to the AO biofilm reactor (2) through the raw water inlet pump (2.1), the sewage flows through the anoxic zone and the aerobic zone of the AO biofilm reactor (2) in sequence, and the effluent enters the intermediate water tank (3 ), part of it flows back to the front end of the anoxic zone through the nitrifying liquid return pump (2.5), and the other part enters the sludge fermentation coupling denitrification reactor (5), and at the same time enters the urban sewage treatment stored in the sludge storage tank (4) The remaining sludge of the plant, after the two are mixed evenly, the sludge fermentation coupled with denitrification and anaerobic ammonium oxidation reaction is carried out to realize sludge reduction and deep denitrification.

The method for applying the device is characterized in that it comprises the following steps:

(1) Start the AO biofilm reactor: the AO biofilm reactor includes two parts, the anoxic zone and the aerobic zone, with a volume ratio of 1:2, in which enriched denitrifying bacteria and anaerobic ammonia oxidation are added to the anoxic zone Bacteria suspended packing Ⅰ, the aerobic zone is added with nitrifying bacteria-enriched suspended packing Ⅱ, the packing is made of polypropylene hollow ring with a diameter of 25-50mm, the density is 0.98%-1.00g/cm ³ , and the porosity is 94%. ～96%, the filling rate is 30%～40%, inject sewage, adjust the total hydraulic retention time to 6h, turn on the stirring system and aeration system, and control the dissolved oxygen DO in the aerobic zone to 2～4mg/L. Sewage and returned nitrification liquid are denitrified and denitrified in the anoxic zone. Part of the nitrite produced in the process is used together with the ammonia nitrogen in the raw water by the anammox bacteria immobilized on the suspended filler Ⅰ, and the anammox reaction takes place further. Nitrogen removal: the mixed solution continues to flow into the aerobic zone to undergo nitrification reaction, converting ammonia nitrogen into nitrate nitrogen, and part of the effluent is returned to the front end of the anoxic zone, and the reflux ratio of the nitrification solution is 300%;

(2) Start the sludge fermentation coupled denitrification reactor: add denitrification sludge with a sludge concentration of 3000-4000mg/L and a mixture of sodium acetate and sodium nitrate with a C/N ratio of 2-3 to the reactor , anoxic stirring, and temperature-controlled heating rods to control the reactor temperature to 30°C until the nitrite accumulation rate in the reactor reaches more than 80%; gradually reduce the dosage of sodium acetate, and add the remaining sewage from the urban sewage treatment plant mud, until the C source produced by the fermentation of excess sludge can completely replace sodium acetate, and then gradually replace sodium nitrate with the effluent from the AO biofilm reactor, so that the nitrite accumulation rate of the reactor remains above 80%, and the sludge Fermentation-coupled denitrification; finally, anammox sludge is added to the reactor, so that the sludge concentration in the reactor is 5000-6000 mg/L, realizing sludge fermentation-coupled denitrification and anammox, and solving the problem of sludge fermentation The problem of secondary pollution caused by the production of ammonia nitrogen;

(3) AO biofilm reactor and sludge fermentation coupled denitrification reactor are operated in series: when the effluent NH ₄ ⁺ of the AO biofilm reactor drops below 3.0 mg/L, the sludge fermentation coupled denitrification reactor removes total nitrogen When the efficiency reaches more than 90%, two reactors are operated in series, the AO biofilm reactor maintains a reflux ratio of 300%, the total hydraulic retention time is 6h, the dissolved oxygen DO in the aerobic zone is 2-4mg/L, and the effluent is stored in the intermediate water tank; The sludge fermentation coupling denitrification reactor uses the automatic control device to set the cycle as follows: ① Sludge intake, start the sludge intake pump, and drive the remaining sludge from the urban sewage treatment plant stored in the sludge storage tank into the sludge fermentation coupling denitrification reactor, Set the mud adding volume to 1/5~2/5 of the effective volume of the reactor, and the mud feeding time is 15 minutes; ②Water inlet, start the nitrification liquid inlet pump, and pump the outlet water of the AO biofilm reactor stored in the intermediate water tank into the reactor , set the water inlet volume to 4/5~3/5 of the effective volume of the reactor, and the water inlet time is 15min; ③Stir in anoxic state, start the stirring device II, control the speed at 80~100rpm, stir in anoxic state for 5h, and use temperature Control the heating rod to control the reactor temperature to 30°C; ④ Settling for 2 hours; ⑤ Drainage, the drainage volume is 2/5 to 3/5 of the effective volume of the reactor, and the drainage time is 15 minutes; ⑥ Sludge discharge, the sludge discharge ratio is 1/2, The mud discharge time is 15 minutes; the whole cycle is 8 hours.

The invention provides a device and method for coupling denitrification with AO biofilm + sludge fermentation to realize deep denitrification of sewage and simultaneous sludge reduction, which has the following four advantages:

(1) Suitable for treating sewage with low C/N ratio and high nitrogen load;

(2) Combining the two deep denitrification technologies of denitrification coupling anammox and fermentation coupling denitrification, the denitrification efficiency is high, and the carbon source is very saved;

(3) The use of biofilm itself hardly produces excess sludge, and can treat excess sludge from external sewage treatment plants to achieve sludge reduction;

(4) Simple operation and convenient management.

Description of drawings

Fig. 1 is a device diagram of the present invention.

In Figure 1: 1—raw water tank, 2—A/O biofilm reactor, 2.1—raw water inlet pump, 2.2—stirring device Ⅰ, 2.3—suspended packing Ⅰ, 2.4—suspended packing Ⅱ, 2.5—nitration liquid return pump, 2.6-Aeration head, 2.7-Air compressor, 2.8-Gas flow meter, 3-Intermediate water tank, 4-Sludge storage tank, 5-Sludge fermentation coupling denitrification reactor, 5.1-Nitrification liquid inlet pump, 5.2-Inlet Mud pump, 5.3—stirring device Ⅱ, 5.4—temperature control heating rod, 5.5—temperature online monitoring controller, 5.6—drain valve, 5.7—mud discharge valve.

Detailed ways

The embodiment of the present invention will be described in detail with reference to FIG. 1 . The AO reactor (2) used has a total volume of 50L and a total effective volume of 35L. There are 8 grids in total, of which the first 4 grids are anoxic areas, and the suspension packing I enriched with anammox bacteria and denitrifying bacteria is placed; The last 4 grids are aerobic areas, and the suspension filler II enriched with nitrifying bacteria is placed, and the filling ratio is 45%; the effective volume of the sludge fermentation coupling denitrification reactor (5) used is 10L, and each cycle is 8h, wherein stirring is 5h, Settling for 2 hours, water inflow, mud inflow, drainage and mud discharge are all 0.25h.

The domestic sewage in the family area of Beijing University of Technology was used as the raw water for the experiment. The specific water quality is as follows: COD concentration is 180-300mg/L, NH ₄ ⁺ concentration is 50-85mg/L, NO ₂ ^- -N and NO ₃ -N are all under detection Below the limit, the COD/N ratio is 2.2-3.5, which belongs to typical low COD/N ratio sewage.

The domestic sewage in the raw water tank (1) and the returned nitrification liquid enter the anoxic zone of the A/O biofilm reactor (2) through the raw water inlet pump (2.1) and the nitrification liquid return pump (2.5) respectively for denitrification reaction. Nitrogen and organic matter are removed, and the nitrite produced in the process is used by the fixed anammox bacteria on the suspended filler Ⅰ (2.3) together with the ammonia nitrogen in the raw water, and the anammox reaction occurs to further denitrify; the mixed solution continues to flow into the well The nitrification reaction occurs in the oxygen zone, and the effluent enters the intermediate water tank, and part of it is returned to the front end of the anoxic zone; the total hydraulic retention time of the AO reactor is 6h, the hydraulic retention time of the anoxic zone is 2h, and the hydraulic retention time of the aerobic zone is 4h. The reflux ratio of the nitrification solution is 300%, and the dissolved oxygen concentration in the aerobic zone is 2-3mg/L;

The nitrifying liquid in the intermediate water tank (3) enters the sludge fermentation coupling denitrification reactor (5) through the nitrifying liquid inlet pump (5.1), and the remaining sludge of the urban sewage treatment plant stored in the sludge storage tank (4) passes through the sludge feeding The pump (5.2) enters the sludge fermentation coupling denitrification reactor (5), sludge fermentation occurs to realize sludge reduction, and the energy generated by sludge fermentation is used for denitrification deep denitrification. At the same time, the NH produced by sludge fermentation ₄₊ is removed by anammox reaction ^.

AO biofilm + sludge fermentation coupling denitrification device treats domestic sewage with low C/N ratio, the pH value of the final effluent is 7.2-7.6, the concentration of ammonia nitrogen is 1.0-3.0mg/L, the concentration of total nitrogen is 10-20mg/L, COD40～ 60mg/L, all stably reaching the national first-class A standard.

Claims (2)

1. a kind of AO biomembrane+sludge fermentation coupling denitrification realizes the device of sewage deep denitrogenation synchronous sludge decrement, special Sign is：Including raw water water tank (1), AO biofilm reactor (2), raw water intake pump (2.1), agitating device I (2.2), suspend Filler I (2.3), floating stuffing II (2.4), nitrification liquid reflux pump (2.5), aeration head (2.6), air compressor (2.7), gas Flowmeter (2.8), intermediate water tank (3), storage basin (4), sludge fermentation coupling denitrification reactor (5), nitrification liquid intake pump (5.1), into dredge pump (5.2), agitating device II (5.3), temperature control heating rod (5.4), on-line temperature monitoring controller (5.5), row Water valve (5.6) and mud valve (5.7)；

Raw water water tank (1) is connected by raw water intake pump (2.1) with AO biofilm reactor (2), and sewage is followed by AO biology The anoxic zone and aerobic zone of membrane reactor (2), water outlet enter intermediate water tank (3), and a part is returned by nitrification liquid reflux pump (2.5) It is flow to anoxic zone front end, another part enters sludge fermentation coupling denitrification reactor (5), while the also storage basin entered (4) excess sludge of the municipal sewage plant stored in.

2. the method for application device as described in claim 1, which is characterized in that include the following steps：

(1) start AO biofilm reactor：AO biofilm reactor includes anoxic zone and the part of aerobic zone two, volume ratio 1: 2, wherein anoxic zone adds the floating stuffing I of gathering denitrifying bacterium and anaerobic ammonia oxidizing bacteria, and aerobic zone adds enrichment nitrifier Floating stuffing II, filler are all made of the polypropylene hollow ring that diameter is 25~50mm, and density is 0.98%~1.00g/cm³, hole Gap rate is 94%~96%, and filling rate is 30%~40%, injects sewage, and adjustment total hrt is 6h, and unlatching is stirred System and aerating system are mixed, the dissolved oxygen DO for controlling aerobic zone is 2~4mg/L；Sewage and the nitrification liquid of reflux anoxic zone into Row denitrification denitrogenation, the part nitrous generated in the process are suspended anaerobism ammonia fixed on filler I together with the ammonia nitrogen in raw water Oxidation bacteria utilizes, and Anammox occurs and reacts further denitrogenation；Mixed liquor continues to flow into aerobic zone and nitration reaction occurs, by ammonia Nitrogen is converted into nitrate nitrogen, and water outlet a part is back to anoxic zone front end, mixed liquid recycle ratio 300%；

(2) start sludge fermentation coupling denitrification reactor：It is 3000~4000mg/L's that sludge concentration is added into reactor Sodium acetate, the sodium nitrate mixed liquor of denitrification sludge and C/N ratio for 2~3, anoxia stirring control reactor with temperature control heating rod Temperature is 30 DEG C, until nitrous accumulation rate reaches 80% or more in reactor；The dosage of sodium acetate is gradually decreased, and adds city The excess sludge of sewage treatment plant of city, until the source C that generates of excess sludge fermentation can substituted acetic acid sodium completely, then gradually use AO The water outlet of biofilm reactor replaces sodium nitrate, so that the nitrous accumulation rate of reactor is remained at 80% or more, realizes sludge Ferment coupling denitrification；Anaerobic ammonium oxidation sludge is finally added into reactor so that in reactor sludge concentration be 5000~ 6000mg/L realizes sludge fermentation coupling denitrification, Anammox, solves sludge fermentation generation ammonia nitrogen and causes secondary pollution Problem；

(3) series operation AO biofilm reactor and sludge fermentation coupling denitrification reactor：When AO biofilm reactor is discharged NH₄ ⁺3.0mg/L when being down to is hereinafter, when sludge fermentation coupling denitrification reactor nitrogen removal rate is up to 90% or more, series operation Two reactors, AO biofilm reactor are maintained the reflux for than 300%, total hrt 6h, aerobic zone dissolved oxygen DO be 2~ 4mg/L, water outlet are stored in intermediate water tank；Sludge fermentation coupling denitrification reactor is as follows using the self-con-tained unit setting period：① Into mud, starts into dredge pump, the excess sludge of the municipal sewage plant stored in storage basin is squeezed into sludge fermentation and couples anti-nitre Change reactor, set plus mud volume is the 1/5~2/5 of reactor dischargeable capacity, is 15min into the mud time；2. intaking, start nitre Change liquid intake pump, the AO biofilm reactor water outlet of intermediate water tank storage is pumped into reactor, sets water inlet volume as reactor The 4/5~3/5 of dischargeable capacity, flooding time 15min；3. anoxia stirring, starts agitating device II, revolving speed control 80~ 100rpm, anoxia stirring 5h are 30 DEG C with temperature control heating rod control temperature of reactor；4. precipitating 2h；5. draining, displacement of volume is The 2/5~3/5 of reactor effective volume, water discharge time 15min；6. spoil disposal, spoil disposal ratio is 1/2, spoil disposal duration 15min；Entirely Period is 8h.