Method for controlling residual sludge reduction in activated sludge-sewage treatment system and reactor

Abstract

The invention provides a method for controlling residual sludge reduction in an activated sludge-sewage treatment system. The method sets three zones, namely an anaerobic zone, a circulating zone and a limited oxygen zone which are connected in turn from a sludge inlet to a sludge outlet in a sludge reduction reactor; the sludge enters the anaerobic zone from the sludge inlet at the upper part, is evenly mixed by stirring, and then downwards flows to the circulating zone; and the sludge circularly flows in the circulating zone under the action of an underwater mixer, then upwards enters the limited oxygen zone, and finally is discharged from the sludge outlet at the upper part of the limited oxygen zone. The invention further provides a reactor for realizing the method for anaerobic / limited oxygen hemicyclic sludge reduction with an arc guide plate. The residence time of the whole reactor is 6 hours, the dissolved oxygen concentration of the limited oxygen zone is 0.5 to 1.1 milligrams per liter, and the ratio of the practical anaerobic / limited oxygen residence time in the reactor is 1.10-1.25:1.0. The radius R1 of the circulating zone of the reactor is 0.5 L1, and the effective height H of the reactor is 4R1. The method has the advantages of good activated sludge reduction effect, low energy consumption, occupied place economy and the like, and can effectively separate inorganic granules in the activated sludge, ensure the effluent effect of the sewage treatment system, well improve the settling performance of the activated sludge, and the like.

Description

technical field [0001] The invention belongs to the technical field of excess sludge reduction in water pollution control, and in particular relates to a sludge reduction reactor for a sludge return bypass in a sewage treatment system. Background technique [0002] Activated sludge method is currently the most widely used sewage biological treatment technology in the world. This method uses activated sludge as the main body to purify sewage through the biochemical degradation of pollutants by microorganisms. The activated sludge system will produce a large amount of excess sludge during the sewage treatment process, accounting for about 0.5% to 1% of the total sewage (water content is about 97%), and the investment and operating costs of sludge treatment account for about 1% of the total investment of the entire sewage plant And 30% to 50% of operating costs. The residual sludge not only contains a considerable amount of toxic and harmful substances such as pathogenic micro...

AI Technical Summary

Problems solved by technology

The biggest advantage of adding an uncoupling agent is that it only needs to add a dosing device in the sewage treatment system, but there are the following problems in practical application: ① After long-term contact, the domestication of microorganisms makes the uncoupling agent invalid; ② Decoupling The dosage of the decoupling agent is usually very large, which leads to an increase in the operating cost of sewage treatment; ③The uncoupling agent is usually a compound that is difficult to biodegrade or has high toxicity to organisms, and there are potential environmental safety problems in the water treatment process

However, there are common problems such as large oxygen consumption, complex operation and management, high treatment costs, and the physical lysis process is easy to damage the growth and metabolism of microorganisms, which in turn has a significant adverse effect on the activated sludge microorganisms in the sewage treatment system.

[0005] The metazoan predation reduction process is to reduce sludge by strengthening the food chain so that energy is lost in the transfer from low trophic level (bacteria) to high trophic level (protozoa and metazoa), which is relatively safe, but metazoan The growth of animals is not easy to control, the operation and management are difficult, and the sludge reduction effect of the sewage treatment system is also difficult to control stably

[0006] Various sewage treatment sludge source reduction technologies have different degrees of residual sludge reduction effects, but these technologies still have the following outstanding and common problems: increased oxygen demand (energy consumption), high cost , the removal ability of nutrients is low, the inorganic substances in the sludge are accumulated in the system, the activity of microorganisms and the sedimentation performance are reduced, etc.

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