Thesis - faculty.ait.ac.th - Asian Institute of Technology

generally unsuccessful in removal of organic material from the raw leachate. The chemical
methods include coagulation and precipitation and oxidation of the organics. The
disadvantage of the coagulation and precipitation is that large amounts of sludge are
produced which is difficult to manage. Neither biological nor chemical/physical treatment
separately achieves high removal efficiency. Physical-chemical treatment is needed to
remove the metals and hydrolyze some of the organics whilst biological treatment is
necessary for stabilization and degradation of organic matter. Looking into these aspects,
landfill leachate treatment requires some advanced treatment technique, to meet the
required effluent standards.
Membrane bioreactor systems are an example of an emerging advanced leachate
treatment technology. Application of the membrane coupled activated sludge process in
leachate treatment is very promising because of the expected effluent quality. The design
of the membrane bioreactor is becoming more affordable and the equipment more reliable.
Membrane bioreactor systems are suspended growth activated sludge treatment systems
that rely upon the membrane equipment for liquid/solid separation prior to the discharge of
the leachate. Two reasons that exist for the poor removal efficiency of the individual
treatment system is the high percentage of high molecular weight organic material and
ammonium concentration to be removed and biological inhibition caused by the heavy
metal which may be present in the leachate.
Sufficient knowledge about the capability and the performance of membrane
bioreactors plants for leachate treatment is yet to be found. Moreover, membrane systems
are often subjected to clogging and this poses serious problems for operation and
maintenance. In order to reduce the problems of frequent membrane clogging, the
application of yeast culture to treat wastewater can be considered. The membrane
bioreactor system with yeast can be employed to treat the wastewater containing high
amount of dissolved solids, high concentrations of organic matter and other substances,
which are difficult to treat using conventional biological systems.
Consequently, depending on the characteristics of the leachate, a combination of
biological and physio-chemical processes can achieve high removal efficiencies. Thus, the
objective of this study is introducing the emerging technology of membrane bioreactors
and its role in leachate treatment. Thereafter, a rationale has been developed for the
treatment of the leachate produced under tropical conditions of Thailand. The experiments
have been conducted in the laboratory to find the performance of membrane bioreactor
using yeast culture (YMBR) and bacteria culture (BMBR) and coupled with ammonia
stripping for removal of organic substances from the landfill leachate. This treatment
system could act as an innovative approach in the future with regard to the landfill
management practices.
1.2 Objectives of the Study
The objectives of this study are to investigate the performance of membrane
bioreactor using yeast culture and bacteria culture and to examine the prospects of
applying membrane bioreactor in landfill leachate treatment. The specific objectives are as
follows:
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