Characterise Phosphorus Removal Of Oyster Shell Based Anaerobic Hydrolysis Acidification Technique And Its Application In An Integrated Process

Severe environment pollution will be caused if sewerage with phosphorusdischarges into water without being disposed. Shell surface is rich in calcium carbonate.It can react with phosphate and realize chemical phosphorus removal if acid isgenerated to release calcium ions in wastewater. This process will not only save reagentcost but also achieve the recycling of shell. This paper proposes a shell based anaerobichydrolysis acidification technique, which uses a shell based anaerobic hydrolysisacidification unit to realize phosphorus removal effect. To this technique, research onthe phosphorus removal characteristics of shell based anaerobic hydrolysis acidificationand the influence of its effluent for the post-processing was carried out by jar-test. Theresults are as follows:The highest acidification rate appeared when the alkali pretreatment had been usedto treat the sludge. Anaerobic hydrolysis acidification process could generate the mostamount of acid if the initial pH value was6.5and temperature was37℃.Shell based anaerobic hydrolysis acidification could realize phosphorus removal.This reaction was basically completed in4hours and the TP removal rate was30.9percent. Meanwhile, VFA was generated and pH value rose, which were both good fornitrogen and phosphorus removal. Within a certain range, the rising of influent TP andCOD concentration was good for the rising of phosphorus removal rate. Thedenitrifying phosphorus removal effect of shell based anaerobic hydrolysis acidificationeffluent was better than raw water and anaerobic hydrolysis acidification effluent. Thiswas because shell based anaerobic hydrolysis acidification can improve pH value andvolatile fatty acid concentration, which were both good for denitrifying phosphorusremoval.The phosphorus removal rate and acid-generating rate of SBR-type shell basedanaerobic hydrolysis acidification were higher than continuous-flow type. So SBR typewas chosen as the reactor of shell based hydrolysis acidification. A proper effluent effecthad been achieved when the integrated process of shell based hydrolysis acidificationand denitrifying phosphorus removal was used to dispose sewage. The average TPconcentration of effluent was0.59mg/L and removal rate was87.5percent. However,when sewage only went through denitrifying phosphorus removal process, its averageTP concentration was2.23mg/L and removal rate was52.6%. The treatment effect ofintegrated process was better.