Development of a novel modified EGSB reactor for municipal sewage treatment at ambient temperatures

ZHOU Xue-fei¹, ZHANG Ya-lei¹, ZHANG Xuan-jun¹, QIANG Zhi-min², ZHAO Jian-fu³

1.Key Laboratory of Yangtze Water Environment of Ministry of Education,Tongji University,Shanghai 200092,China;2.State Key Laboratory of Pollution Control and Resource Reuse,Tongji University,Shanghai 200092,China;3.Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China



Abstract:

A novel modified expanded granular sludge bed(EGSBm) reactor was developed for anaerobic treatment of municipal sewage with mixed liquid recirculation instead of effluent recirculation commonly adopted by a conventional EGSB(EGSBc) reactor.Performances of these two reactors were compared in treating municipal sewage at ambient temperatures ranging from 8 to 26 ℃.At an upflow liquid velocity(Vup) of 10.3 m/h,the mean concentrations of filtrated COD(CODfilt) and COD of the EGSBm effluent were determined to be 59.4 and 95.9 mg/L,respectively,which were significantly lower than those of the EGSBc effluent operated under identical experimental conditions.When the organic loading rate was suddenly increased from 1.2 to 7.2 kg COD/(m3·d),the EGSBm regained the removal efficiency of previous operation phase in 10 d.Hydrodynamic characteristics of the reactors were compared using the residence time distribution(RTD) model.It was found that the treatment efficiency of EGSBm kept increasing as the Vup increased.The polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis(PCR-DGGE) technique was used to analyze the microbial diversity in EGSBm.Fingerprinting pattern indicated that some species in the inoculating sludge were still reserved in the granular sludge of EGSBm,moreover,several new species occurred.

Key words:  modified expanded granular sludge bed reactor  municipal sewage  anaerobic treatment  hydrodynamic characteristic  PCR-DGGE

DOI：10.11916/j.issn.1005-9113.2009.04.021

Clc Number:X703

Fund: