Prof. Jarungwit Boonnorat

Department of Environmental Engineering, Rajamangala University of Technology Thanyaburi

 

Title

Effect of landfill leachate effluent to seed germination by using acclimatized sludge in activated sludge and membrane bioreactorDesign

 

Abstract

In the absence of research on phytotoxicity of landfill-leachate effluent, this study comparatively investigates the phytotoxic effect of landfill leachate effluent of two-stage activated sludge (AS) and two-stage membrane bioreactor (MBR) with acclimatized sludge on germination of Lactuca sativa and Vigna radiata. The AS and MBR are operated under two concentrations of landfill leachate influent: moderate (condition 1) and elevated (condition 2). The results show that, under condition 1, the AS and MBR efficiently remove 80 – 96 % of organic compounds and nutrients and 81 – 100 % of harmful micropollutants. Under condition 2 with elevated influent concentration, MBR is more effective in biodegrading micropollutants than the AS system. The germination rate (GR) and germination seed index (GSI) of L. sativa and V. radiata germinated with AS and MBR effluent from condition 1 are 100 % and 1.29 – 1.54. Under condition 2, the GR and GSI of plant seeds with AS effluent are reduced to 80 % and 0.65 – 0.77, while those with MBR effluent are 100 % and 1.27 – 1.38. Quantitative real-time polymerase chain reaction (qPCR) analysis indicates that the bacterial community in bioaugmented MBR is more abundant than in the AS, especially ammonia oxidizing bacteria, Nitrobacter, and Nitrospira, which play an essential role in micropollutant biodegradation. The bacterial abundance and community composition make the MBR more suited to elevated landfill-leachate influent concentration, and the system is more effective in removal of micropollutants than the AS, as evidenced by lower phytotoxicity. As a result, MBR is operationally and environmentally more favorable. Besides, the technology could potentially be applied to water reclamation