CN100412009C - A Nitrification Process for Biological Treatment of Sewage - Google Patents

Abstract

The invention relates to a sewage biological treatment nitrification process, which is most suitable for urban sewage treatment. Divide the sewage into the anoxic pool, the aerobic pool and between the aerobic pool and the secondary sedimentation tank at the same time in proportion. The aerobic pool is divided into three or more water inlet points. After the oxygen process, it enters the aerobic tank, mixes with the sewage that directly enters the aerobic tank for aeration, and the mixed liquid is separated from solid and liquid in the secondary sedimentation tank. Compared with the existing technology: it has short-term high efficiency, simple process, less land occupation, less capital investment, less equipment, low operating cost, good denitrification effect, stable operation, strong impact load capacity, and can effectively prevent sludge bulking Occurrence and other characteristics have wide applicability in this technical field.

Description

A Nitrification Process for Biological Treatment of Sewage

technical field

The invention relates to a sewage biological treatment nitrification process, which is especially suitable for nitrogen and phosphorus removal treatment of sewage.

Background technique

The problem of water pollution caused by nitrogen pollution in my country is relatively serious, and lake "blooms" and offshore "red tides" occur from time to time. Eutrophication of water body has endangered agriculture, fishery, tourism and many other industries; it also poses a threat to drinking water sanitation and food safety. At present, to control nitrogen pollution, common engineering technologies at home and abroad include air stripping method, selective ion exchange method, breakpoint chlorination method, biological denitrification method, etc. Among them, biological denitrification is the most economical and effective treatment technology. In recent years, many countries have strengthened the research on biological denitrification, and have made great breakthroughs in theory and technology. A large number of new biological denitrification technologies marked by "simultaneous nitrification-denitrification process" and "anammox process" have come out successively, which not only make up for the defects of traditional nitrification-denitrification process, but also improve the efficiency of wastewater denitrification. It reduces the cost of denitrification of wastewater, and also fills the gap that there is no direct biological denitrification technology for high-concentration nitrogen-containing wastewater. However, in order to achieve a good denitrification effect in the existing denitrification process, sufficient aeration time must be ensured to meet the growth of a large number of nitrifying bacteria and achieve the purpose of nitrification, so the entire reaction time is relatively long, generally 8 hours Therefore, the denitrification efficiency is low and the cost is high.

Contents of the invention

The object of the present invention is to provide a high-efficiency nitrification process for sewage biological treatment with simple process, short reaction time, high efficiency and low cost.

The technical solution adopted in the present invention is: the sewage undergoes anoxic, anaerobic and aerobic biological treatment processes, and then enters the secondary sedimentation tank for mud-water separation, discharges the supernatant during the sedimentation, and at the same time returns part of the sludge. Divide the sewage into the anoxic pool, the aerobic pool and between the aerobic pool and the secondary sedimentation tank at the same time. The aerobic pool is divided into three or more water inlet points. After anaerobic action, it enters the aerobic tank, mixes with the sewage that directly enters the aerobic tank for aeration, and the mixed solution is separated from solid and liquid in the secondary sedimentation tank. Part of the sludge returns to the non-aerated tank, and the proportion of sludge return is controlled to ensure that the non-aerated tank and the aerobic tank have sufficient sludge concentration. Anoxic pools and anaerobic pools for sewage treatment are built together or separately; anoxic pools, anaerobic pools and aerobic pools are built together or separately.

The beneficial effect of a kind of sewage biological treatment nitrification process of the present invention is:

a. Short-term high efficiency. The aeration time required by the technical process can be greatly shortened, and the effect of removing more than 95% of ammonia nitrogen (35mg/L) by aeration is about 4 hours, and the reaction time is about half of the traditional nitrification process.

b. The process is simple. The technical process shows the advantage of being simpler than the traditional denitrification process both in structure and process flow, and the process appears to be relatively smooth.

c. Less land occupation, less investment in infrastructure. Because the concentration of sludge in each reactor of this technical process is high, the reaction rate is increased to make the reaction time shorter, so the corresponding reaction volume can be relatively small, that is, the construction of structures and the impact on the land of the entire sewage treatment plant can be reduced. occupancy. At the same time, the process is relatively simple, the required equipment can be reduced, and the corresponding cost can also be reduced. Generally using this process, infrastructure and equipment investment costs can be saved by about 1/4 compared with traditional processes.

d. Stable operation, strong impact load resistance, and can effectively prevent sludge bulking.

e. Save operating costs. In order to achieve a good denitrification effect in the traditional denitrification process, a large ratio (usually 100-400%) of the nitrification liquid in the aeration tank must be refluxed, and at the same time, a long enough aeration time must be ensured to promote ammonia nitrogen Nitrification, so the energy consumption is larger and the operating cost is higher. In actual operation, there is no internal backflow, and the aeration time is greatly shortened, so energy consumption can be greatly reduced and operating costs can be saved.

Description of drawings

Accompanying drawing is the flow chart of nitrification process of sewage biological treatment of the present invention.

Detailed ways

An embodiment of the present invention will be further described below in conjunction with accompanying drawing:

The present invention is a sewage biological treatment nitrification process, the main structure is a non-aeration pool and an aerobic pool composed of anoxic pool and anaerobic pool, and the anoxic pool and anaerobic pool in the non-aerated pool can be built together or can be Separate construction, non-aerated pool and aerobic pool can be built together or separately. Divert the sewage into the non-aerated tank and the aerobic tank at the same time. The aerobic tank is divided into four water inlet points, and there is a water inlet point between the aerobic tank and the secondary sedimentation tank. The sewage entering the non-aerated tank undergoes anoxic and anaerobic effects, then enters the aerobic tank, mixes with the sewage directly entering the aerobic tank for aeration, and then the mixed solution enters the secondary sedimentation tank for mud-water separation, and part of the sewage Mud returns to the non-aerated tank.

The operation process of the whole sewage treatment system is as follows:

(1) The water intake of the non-aerated tank consisting of anoxic tank and anaerobic tank is 45%, the water intake of the aerobic tank is 50%, and the water intake of the water intake point between the aerobic tank and the secondary sedimentation tank is 5%; There can be multiple water inlet points in the pool. If there are four water inlet points in the aerobic pool, the water inlet of the first and fourth water inlet points is 10% each, and the water inlet of the second and third water inlet points is 10%. Each is 15%; according to the actual water quality, the proportion of water inflow to all water inflow points can be adjusted in order to improve the efficiency of ammonia nitrogen oxidation;

(2) By controlling the amount of aeration, the content of dissolved oxygen in the aerobic tank is maintained at about 1-2mg/L;

(3) Control the reflux ratio to ensure that the non-aerated tank and the aerobic tank have sufficient sludge concentration (>3000mg/L), so that the aerobic tank is in a state of high sludge concentration and low nutrition, and relatively inhibits the proliferation of decarbonizing microorganisms , to promote the proliferation of nitrifying bacteria.

(4) Introduce 10% sewage at the first water point of the aerobic tank, and maintain the sludge concentration at a relatively high level for aeration to degrade organic matter to achieve decarbonization. ) can continue to maintain the denitrification process without aeration. The sludge is returned to the non-aeration tank for denitrification and release of phosphorus. During the operation, various operating parameters are continuously adjusted until the operating effect of the entire system reaches the optimum.

Claims (2)

1. biological sewage treatment nitration processes, it comprises anoxic, anaerobic and aerobic biological treatment process, and carry out secondary sedimentation, discharge supernatant liquor in the precipitation, falling part mud simultaneously refluxes, it is characterized in that: sewage is shunted in proportion entered simultaneously between anoxic pond, Aerobic Pond and Aerobic Pond and the second pond, Aerobic Pond divides three or three above water entry water inlets, enter into Aerobic Pond again after entering the sewage experience anoxic of anoxic pond and anaerobic process, with directly enter sewage in the Aerobic Pond and mix and carry out aeration, mixed solution carries out solid-liquid separation at second pond.

2. a kind of biological sewage treatment nitration processes according to claim 1 is characterized in that: anaerobic pond and described anoxic pond are built jointly or are divided and build.