A sewage treatment method with adjustable nitrogen and phosphorus removal capacity

Abstract

The invention discloses a sewage treatment method capable of adjusting nitrogen and phosphorus removal capacity, belonging to the field of sewage treatment. The sewage of the present invention passes through the reaction tank and the secondary sedimentation tank in turn to realize enhanced nitrogen and phosphorus removal. When the operation mode beyond sludge is adopted, the total phosphorus removal rate is >90% or the effluent TP<1mg / L, ΔBOD / ΔTN<4, within the system The maximum flow flux in each area does not exceed 2.2Q, and the phosphorus content of the sludge in the return sludge is >4%. It has high-efficiency nitrogen and phosphorus removal, energy-saving and low-carbon operation, high load, and less land occupation. It can realize denitrification and phosphorus removal and TN removal. The efficiency is not limited by the reflux ratio, the control is simple, the operation and management are convenient, etc. The system of the present invention is composed of a reaction tank, a secondary settling tank and connecting pipelines. The reaction tank is sequentially composed of a pre-anoxic zone, an anaerobic zone, a middle sink zone, an aerobic nitrification zone, a denitrification zone, Aerobic decarbonization area, water outlet area, connecting pipelines include main water inlet pipe, branch water inlet pipe, water outlet pipe, sludge overflow pipe, sludge return pipe, excess sludge discharge pipe, etc., the process flow is simple.

Description

technical field [0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a sewage treatment method capable of adjusting nitrogen and phosphorus removal capacity. Background technique [0002] Biochemical treatment of sewage is mostly based on the traditional mechanism of nitrogen and phosphorus removal. Nitrification process, including nitrification and denitrification; nitrification, that is, autotrophic nitrifying bacteria (AOB, NOB) under aerobic conditions, NH 4 + -N→NO 2 - -N→NO 2 - -N; denitrification, that is, denitrifying bacteria under anoxic conditions, with NO X - as electron acceptor, organic matter as electron donor, NO 3 - -N→NO 2 - -N→N 2 . The biological phosphorus removal process includes anaerobic phosphorus release, aerobic transitional phosphorus absorption, and discharge of excess sludge to achieve biological phosphorus removal; in the anaerobic process, phosphorus-accumulating bacteria absorb org...

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Problems solved by technology

[0006] 3) There is competition for carbon sources in nitrogen and phosphorus removal, phosphorus accumulating bacteria can only use volatile fatty acids in organic matter, and other forms of organic matter need to be hydrolyzed into volatile fatty acids before they can be used by phosphorus accumulating bacteria; The requirements for carbon sources are slightly lower than those of phosphorus accumulating bacteria, but they can only use low-carbon organic matter. There is a competition for the quality and quantity of carbon sources between denitrifying bacteria and phosphorus accumulating bacteria; in general, biological denitrification requires influent C / N>4, biological nitrogen and phosphorus removal requires influent C / N>7, while domestic general domestic sewage influent C / N is generally <4, which belongs to insufficient carbon source and needs external carbon source; No organic carbon source is needed, and when the organic carbon source exceeds a certain amount, it will inhibit the metabolism of the nitrifying bacteria

The dual-sludge system, that is, two sets of biological systems, bears long-sludge-age and short-sludge-age bacteria respectively. The system structure is complicated, the control is difficult, and the requirements for operation and management are high, so it is difficult to apply in a large area in the project

in the traditional A 2 Increase biofilm in / O, such as installing fixed packing in the aerobic area, but the hydraulic shear provided by normal aeration is not enough to promote the normal renewal of microorganisms on the fixed packing, and long-term operation will produce dead sludge areas, which will seriously reduce nitrification efficiency; If in traditional A 2 / O is loaded with a suspended carrier, although a mud film composite process has been formed, it cannot create conditions for denitrification and phosphorus removal, and the suspended carrier system, when the concentration of suspended sludge in the system is too large, the suspended sludge will be mixed with the suspended carrier The biofilm on the surface will compete and reduce the nitrification efficiency

[0009] At the same time, it should be noted that although denitrification and phosphorus removal can improve the utilization rate of carbon sources, once the C / N of influent water increases, its carbon source consumption has limitations, which may lead to excessive organic flow into the nitrification area, affecting the nitrification of the system function; however, if the design considers the nitrification design when the C / N is high, it will inevitably increase the pool capacity of the nitrification area and increase the cost, which is uneconomical; Flexible adjustment of pure membrane process and mud-membrane composite process can ensure the treatment effect, reduce investment and improve operating efficiency

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