A method for excess sludge treatment and resource recovery and a method for improving the yield of vfas

Abstract

The invention discloses a method for regulating the acidogenic effect of liquid state fermentation of sludge and removing nitrogen and phosphorus on line, which belongs to the field of turning organic solid wastes into sources. The method couples and synchronizes a denitrifying and dephosphorizing device and an upflow anaerobic sludge fluidized bed (UASB) to achieve the objective of removing nitrogen and phosphorus and increasing the yield of volatile fatty acid (VFA). The denitrifying and dephosphorizing device, which is of an upflow type, receives fermented liquid coming from the UASB after the liquid state fermentation of sludge, dissolved magnesium salt is added according to a produced struvite proportion, the denitrified and dephosphorized liquid flows back into the UASB, and produced struvite precipitate is removed from the bottom of a reactor. Compared with ammonia nitrogen and total phosphorus in the fermented liquid of a UASB not synchronized with a denitrifying and dephosphorizing device, ammonia nitrogen and total phosphorus in the fermented liquid of the method disclosed by the invention are respectively decreased by 78.09 plus or minus 0.30 percent and 94.61 plus or minus 0.51 percent, and meanwhile, 1.52 plus or minus 0.04g of struvite / g of PO4<3-> is recovered. Moreover, the proportions of acetic acid and propionic acid are increased to 66.76 plus or minus 0.23 percent and 16.54 plus or minus 0.17 percent, and the directional acidogenesis of acetic acid and propionic acid is enhanced.

Description

technical field [0001] The invention relates to a method for excess sludge treatment and resource recovery and a method for increasing the yield of VFAs, belonging to the field of organic solid waste recycling. Background technique [0002] The anaerobic fermentation of municipal surplus sludge to produce volatile fatty acids (VFAs), as a way of sludge resource utilization, has attracted increasing attention in sewage treatment plants. Sludge liquid fermentation is an efficient acid production method, which has the advantages of high fermentation intensity, high VFAs production and low operating energy consumption. However, there are also some problems in this method: on the one hand, a large amount of ammonia nitrogen is produced due to the gradual consumption of protein substances during the fermentation process, and the concentration of ammonia nitrogen can reach more than 1000 mg / L. The efficiency of anaerobic fermentation is low; on the other hand, the nitrogen and pho...

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Problems solved by technology

However, there are also some problems in this method: on the one hand, a large amount of ammonia nitrogen is produced due to the gradual consumption of protein substances during the fermentation process, and the concentration of ammonia nitrogen can reach more than 1000 mg / L. The efficiency of anaerobic fermentation is low; on the other hand, the nitrogen and phosphorus content of the fermentation liquid is high, far exceeding the discharge limit of the sewage plant, and it cannot be directly put into the sewage plant as a carbon source. The fermentation liquid often needs to be denitrified and dephosphorized. can be used as an external carbon source

However, due to the need for solid-liquid separation and chemical denitrification and phosphorus removal of the sludge after fermentation, the subsequent treatment steps of the fermentation broth are increased, which is not conducive to the operation and management of the entire process. operation, the total cycle of sludge anaerobic fermentation and nitrogen and phosphorus removal is relatively long, the efficiency is low, and the energy consumption is too large

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