A low-carbon nitrogen ratio biological nitrogen and phosphorus removal method

Abstract

The invention discloses a low-carbon nitrogen ratio biological nitrogen and phosphorus removal method, which belongs to the field of sewage treatment. The sewage of the invention passes through the reaction tank and the secondary sedimentation tank in turn to achieve enhanced denitrification and phosphorus removal. The TP removal rate is >90% or the effluent TP<1mg / L, ΔBOD / ΔTN<4, and the maximum flow rate of each zone in the system does not exceed 2.2Q , the sludge phosphorus content of the return sludge is >4%, with high efficiency denitrification and phosphorus removal, energy-saving and low-carbon operation, high load, low land occupation, denitrification and phosphorus removal, TN removal rate is not limited by the reflux ratio, and the control is simple It has the advantages of convenient operation and management. The system of the invention is composed of a reaction tank, a secondary sedimentation tank and a connecting pipeline. The reaction tank is sequentially composed of a pre-anoxic zone, an anaerobic zone, a middle sedimentation zone, an aerobic nitrification zone, a denitrification zone, a The aerobic decarbonization area and the water outlet area, the connecting pipelines include the main water inlet pipe, the branch water inlet pipe, the water outlet pipe, the sludge overrun pipe, the sludge return pipe, the excess sludge discharge pipe, etc. The process is simple.

Description

technical field [0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a low-carbon-to-nitrogen ratio biological denitrification and phosphorus removal method. Background technique [0002] Biochemical treatment of sewage is mostly based on the traditional mechanism of nitrogen and phosphorus removal. Denitrification process, including nitrification, denitrification; nitrification, that is, autotrophic nitrifying bacteria (AOB, NOB) under aerobic conditions, NH 4 + -N→NO 2 - -N→NO 2 - -N; denitrification, that is, the denitrifying bacteria in 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

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