Research On Anaerobic Sequencing Batch Reactor Load Characteristics And Its Design

Anaerobic treatment of high concentration organic wastewater has a variety of technological forms,but any variation or improvements are put forward for centring on the fundamental purpose of treating wastewater with high efficiency and high-volume loading.Anaerobic sequencing batch reactor（ASBR）is the third generation of new anaerobic reactor.It has a lot of advantages,such as simple structure,small investment,low operating cost.What’s more,biological flocculation and solid-liquid separation by forming granular sludge with methanosarcina thermophila are very good.Therefore,it is of great significance to study phenomena of start-up process,influencing factors during operation,method of increasing volume loading rapidly to impell industrialization of ASBR.For this issue,five tasks were mainly carried out on the problem that how to effectively improve ASBR volume loading with the aim of industrialization of ASBR and results showed as follows.（1）Research on ASBR start-up process.It was supposed to explore startup rules by observing changes of COD,alkalinity,volatile fatty acids of effluent and sludge morphology during initiation stage of ASBR.Results showed that:volume load of ASBR could be improved from 3kgCOD/m³·d to 8kgCOD/m³·d and kept the COD removal rate over 80%in a relatively short hydraulic retention time（1d）after 26 days cultivation.Electron microscope scanning showed that there was a big difference among different volume load in sludge morphology.The granules would be larger and tighter with higher volume load.（2）Research on operational process of ASBR.It was supposed to explore influence laws during ASBR operation and optimal combination plan of hydraulic retention time,sludge quantity and basicity by designing single factor experiment and orthogonal experiment with monitoring COD removal rate.It was found that influence order of the three factors on the operation of ASBR was hydraulic retention time>alkalinity>sludge quantity.ASBR system worked best when amount of sludge was 300mL,hydraulic retention time was 18h and ratio of carbon and bicarbonate sodium was 2.5:1.（3）Research on optimal method of increasing ASBR’s volume load rapidly,which could be realized by increasing influent COD concentration of ASBR₂ and shortening hydraulic retention time of ASBR₁.It was found that after 20 days,volume loading rate of ASBR₁ and ASBR₂ were increased from 1kg kgCOD/m³·d up to 20kgCOD/m³·d eventually and COD removal rate was all above 70%,but COD removal rate of ASBR₁ was higher than ASBR₂.When the volume loading rate was more than 20kgCOD/m³·d,pH value of ASBR₁ and ASBR₂ dropped to 5.8 and 5.5,meanwhile COD removal rate dropped to 50.3%and 52.6%respectively.But ASBR₂ could restore to pH 7.2 within 6 days,COD removal rate was 70%and the system recovered by prolonging reaction time,however,ASBR₁ was unrecoverable.This showed that under affordable condition,it was more stable with the method by increasing influent COD concentration,while in special cases,shorting hydraulic retention time was stronger,as well as costing shorter time to increase the same load.（4）The anaerobic sludge in ASBR₁ and ASBR₂ and original sludge were analyzed by 16SrDNA high-throughput sequencing technology.Result showed that ASBR₁ had more microbial species than ASBR₂,but the amount of methane-producing bacteria was not as large as ASBR₂,in the other words,the microbial community structure in ASBR₁ was richer and more stable.（5）Feasibility study of ASBR in the same gas chamber.According to the results of test in laboratory experiments and optimum process parameters,it could be concluded to design ASBRs with the same air chamber by enlarging the result of the experiment as pilot-scale（10m³）and perform fit-gap analysis.It was estimated that production cost estimation of ASBR processing was 6151.12RMB,which provided basic data for operation of ASBR in the same gas chamber...