Experimental study on zero excess sludge production process with ozonation unit in MBR process

WANG Zheng¹, WANG Lin², WANG Bao-zhen¹, LIU Shuo¹, IANG Yi-feng³

1.School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China;2.School of Environmental Science and Engineering, Ocean University of China, Qingdao 266003, China;3.College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, China



Abstract:

In order to investigate the influence factors of zero excess activated sludge (EAS) process by ozonation, a 100 L membrane bioreactor coupled with a sludge ozonation unit (MBR-SO) was performed for 80 d without EAS wasting. Some mathematical models were developed to elucidate the relationship between process parameters and the operating effects. It is considered that the sludge lysing ratio (ξ), produced COD per unit mass lysed MLSS (η), observed sludge yield coefficient (Yobs) and intrinsic yield coefficient for COD produced by lysed sludge (Y2) significantly affect the flowrate to ozonation unit (q). When q is 0.0067 times of influent flowrate (Q) and ξ is about 0.72 for each batch ozonation, a relatively stable MLSS concentration of 8168 mg/L and zero Yobs are achieved in the MBR-SO system. The calculation of sludge disintegration number indicates that the high ξ can apparently decrease the sludge amount needed for ozonation. At the same ozone dose, the low input ozone concentration and high flowrate can enhance the sludge lysing effects and a low energy consumption of 0.041 Yuan/m3 wastewater is obtained.

Key words:  excess activated sludge  ozonation  MBR  modeling  economic analysis

DOI：10.11916/j.issn.1005-9113.2010.01.008

Clc Number:X703.1

Fund: