Experimental Study On Rapid Start-up And Mechanism Of Phosphine Generation Of ASBR System

In this study,the Anaerobic sequencing reactor?ASBR?was used as the test object,and the anaerobic and anaerobic digesting tank sludge of Lijiao Sewage Treatment Plant and Xiaoguwei Island in Panyu District,Guangzhou.The anaerobic sediment in the river channel of Beiting village was inoculated with sludge.The effects of various polyquaternium dosages and dosage methods on the start-up of ASBR were compared.Three different organic loads were selected for different carbon-phosphorus ratios,aiming to explore the mechanism of phosphine generation after the rapid start of the ASBR system,and provide a new idea for the realization of anaerobic dephosphorization.To begin with,the different dosages and its methods were used as the main research technical parameters to judge how to optimize the addition of PQA,and monitor the degradation of organic matter as well as TP removal efficiency during the start-up process of the ASBR.By the 16S rRNA of sludge samples,the effect of sludge sedimentation performance,microbial colony on the surface of sludge and the structure determined the optimum dosage and method of PQA to achieve quick-start of the ASBR.Furthermore,analyzed the research on the degradation ability,gas production,alkaline phosphatase,dehydrogenase bioenzyme activity and the mutual relationship between the different organic load conditions,and determined the organic load on the phosphine production in the ASBR.Last,The impact of the system on phosphate removal and phosphine generation from the perspective of physical,chemical and biological effects,speculates on possible phosphine production pathways.The main research results are as follows:When the amount of sludge was 12.0 g MLSS/L,the PQA was added once every two days,and each dose of 10 mg/L is most effective.After adding PQA,the degraded organic matter and phosphate reduction function of the ASBR system was stronger,and the colonies with denser structure and more uniform microbial distribution are formed more quickly,and the rapid start of ASBR was realized.After the successful quick start-up,the microbial diversity and community structure of the system decreased,and the PQA added fewer system species but higher community diversity.At the level of the door,the growth of Bacteroidetes was obvious,Proteobacteria was inhibited,and the addition of PQA had a toxic effect on Proteobacteria.New strains such as WS6 and Saccharibacteria appeared to be able to achieve anaerobic biological phosphorus removal.At the level of the grading,the growth of vadinHA17 and Spirochetes was speculated to be related to anaerobic phosphorus removal.?-proteobacteria was inhibited,and the inhibition of PQA was stronger.At the genus level,?-proteobacteria and Spirochetes were inhibited,but Saccharibacteria grew.It was speculated that Mesotoga,Synergistaceae,Aminicenantes,Spirochetes,and?-proteobacteria were related to the removal of COD and TP.The COD removal rate of ASBR system under different organic loading conditions was96%⁹7%,the TP removal rate increased with the increase of organic load,and the COD removal of OLR=5.0gCOD/?L·d?system was more stable,while OLR=2.5gCOD/?L·d?the system TP removal of was more stable.In the typical cycle,the TP removal rates were 35.5%,46.1%,and 49.30%,respectively.The COD removal rates were 96.16%,96.20%,and 96.63%,respectively.The PH₃ yields were 13.90 ng/m³,30.28 ng/m³,and 32.82 ng/m³,respectively.The average values MBP were 673.86 ng/Kg dry sludge,751.95 ng/Kg dry sludge and2872.39 ng/Kg dry sludge,respectively,and the yields of CH₄ were 587.03 mL,1356.17 mL and 2194.15 mL,respectively.During the period,TP removal rate and CH₄ yield were significantly positively correlated with COD removal rate,and MBP was positively correlated with APA,but there was no significant correlation between PH₃ and APA.In addition,for systems with OLR=2.5gCOD/?L·d?which carbon-phosphorus ratio is 50:1,there was a significant positive correlation between CH₄ yield and DHA;there was no correlation between CH₄ yield and DHA in systems with high OLR.A small part of the phosphate removal in the ASBR system was the dilution of the original mixture in the system,most of which was the result of biological action.From a thermodynamic point of view,the phosphate reduction reaction Gibbs free energy was greater than zero,which was a non-spontaneous reaction.In the phosphate reduction process,the Nernst equation was used to calculate that the potential difference was less than 0V,and the addition of a strong reducing agent was required to achieve the reduction of phosphate to phosphine.The main metabolic pathways of glucose dehydrogenation degradation under anaerobic conditions included EMP,HMP,ED and PK.Especially in the HMP metabolic pathway,a small amount of ATP and a large amount of reduced co-enzyme I and II were produced,which could provide sufficient reducing power.After the dehydrogenation of the inorganic substrate,the electrons were reversely transferred and consume energy and provide a strong reducing power,so that the phosphate in the ASBR system could be reduced to phosphine.