Primary sludge fermentation pretreatment system for improving performances of dephosphorization and denitrification on town sewage

Abstract

The invention provides a primary sludge fermentation pretreatment system for improving the performances of dephosphorization and denitrification on town sewage, which comprises a primary settlement and fermentation tank (1) which integrates the functions of primary settlement and fermentation into one body, a water inlet and distribution system (2), a mud scraping and sucking bridge (3) arranged at the top of the primary settlement and fermentation tank (1), a plurality of propellers (4) arranged on the mud scraping and sucking bridge (3), a water outlet weir plate (5) arranged on the upper part of the primary settlement and fermentation tank (1), a water outlet collecting tank (6), and a slurry discharging subsystem arranged at the bottom of the primary settlement and fermentation tank. The water inlet and distribution system is connected with a grid and a sand setting treatment water outlet (A) arranged in front thereof via a pipeline. The water outlet collecting tank (6) is connected with a subsequent biological denitrification and dephosphorization process structure (B) via a pipeline. The slurry discharging subsystem is connected with a subsequent sludge treatment structure (C) via a sludge pump and a pipeline. The system integrates the functions of biological flocculation, precipitation, hydrolysis and fermentation into one body and can improve the quality of water flowing into town sewage treatment plants. The system can also improve biological denitrification and dephosphorization capabilities and the operation effect of the whole process.

Description

Technical field: [0001] The invention relates to a pretreatment system for urban sewage, in particular to a primary sedimentation fermentation pretreatment system for improving the phosphorus and nitrogen removal performance of urban sewage. Background technique: [0002] The pollutant removal objects and discharge control indicators of urban sewage treatment plants mainly include chemical oxygen demand (COD), biochemical oxygen demand (BOD 5 ), suspended solids (SS), ammonia nitrogen (NH 3 -N), total nitrogen (TN) and total phosphorus (TP). According to Announcement No. 21 issued by the State Environmental Protection Administration in 2006, Article 4.1.2.2 of "Pollutant Discharge Standards for Urban Sewage Treatment Plants" (GB 18918-2002) was revised to "The discharge of effluent from urban sewage treatment plants into the national and provincial determination For key river basins and closed and semi-enclosed waters such as lakes and reservoirs, the A standard of the fir...

AI Technical Summary

Problems solved by technology

However, most urban sewage treatment plants in my country have significantly lower carbon-to-nitrogen ratios in the influent, and the influent BOD 5 The / TKN ratio is only 3-4, which is significantly lower than 5-6 in developed countries, seriously affecting the ability of biological phosphorus and nitrogen removal

In the case of setting up a conventional primary sedimentation tank, due to the different removal ratios of carbon and nitrogen, the problem of low carbon-nitrogen ratio will be more prominent, and BOD 5 The / TKN ratio can be reduced to a level of 2.5-3, and the treatment efficiency of the subsequent biological phosphorus and nitrogen removal process units will be more obviously adversely affected

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