Wednesday, July 15, 2009

Development And Application Of Bacteria sp. for Municipal Solid Waste Treatment System

Primary sedimentation tank at a rural treatmen...Image via Wikipedia

In the recent years, Malaysian Government has focused on improving and upgrading the existing sewerage systems and facilities, which is inadequate in terms of treatment efficiency. In many cases, the effluent quality has not met the effluent standards required by the authority. Ujang et al (2002) has reported that untreated and inadequate treatment of wastewater has been the major factor in causing severe pollution of rivers and near-shore areas in Malaysia. As for example, municipal sewage has principal contaminations, which fall into the categories of Nitrogen, Phosphorus, pathegonic organism, heavy metals and trace organics. The pathogens include bacteria, viruses, protozoa and helminthes. Those pollutants have the potential to create public health and environmental problem, particularly in urban areas.

Referring to the report by United States Environmental Protection Agency (2004), there are several key challenges faced by wastewater treatment today. Many of the wastewater treatment and collection facilities are now old and worn, and require further improvement, repair or replacement to maintain their useful life. The far more complex character and quantity of contaminants presenting problems today has also lead to the challenges for the present wastewater treatment. Besides that, the population growth has taxing many existing wastewater treatment systems and creating a need for new plants. Farm runoff and increasing urbanization provide additional sources of pollution not controlled by wastewater treatment.

Thus, due to the trends in urban development along with rapid population increase, municipal wastewater treatment deserves greater emphasis. There is need to improve and sustain the municipal wastewater treatment technology.

Currently, the biological wastewater treatment technology has received more recognition compared to the physical-chemistry or chemistry treatment system. Gotvajn et al (2009), has reported that the biological method are usually preferred over physicochemical ones in removing the majority of pollutants in wastewater treatment. Furthermore, the waste treatment research in Latin America using physical-chemistry, chemistry and biology has shown that biological method are adequate for the reduction of chemical oxygen demand (COD) (Lozano et al., 2009).
Besides that, Zhao et al (2008) has reported that aerobic biological wastewater treatment systems utilize mixed microbial consortia to transform organic and inorganic pollutants to innocuocus byproducts, allowing municipal and industrial wastewater to be released to the environment without detriment. Due to this, the biological methods seem to offer effective solution for in order to improve the municipal wastewater treatment.

Basically, wastewater purification by the biological method consists in using the organic and nitrogen pollution as a nutrient substrate for the purifying biomass. The idea behind all biological methods of wastewater treatment is to introduce contact with bacteria (cells), which feed on the organic materials in the wastewater, thereby reducing its BOD content.
The biological wastewater treatment offers certain goals. i.e. reduces labor time, enhances BOD/COD removal, degrades wide range of organic waste, increases the system efficiency, reduces sludge build up and reduces hydrogen sulphide cost.

The advantage of using biological systems is that, operation takes place at ambient temperature. This consequently saves on the energy consumption. The treatment operations are located outdoor and this implies that the system must be able to operate at seasonally varying temperatures. Cells come in a mix of many types, and accommodation to a temperature change is simply accomplished by self adaptation of the cell population. Similarly, a change in composition of the organic material leads to a spontaneous change in cell population, with the types best suited to digest the new material growing in large numbers than other cell types.

Thus, in this study, the main efforts will be developed and apply the efficient bacteria in the municipal wastewater treatment and hence to offer a new alternatives for the municipal wastewater treatment technologies.

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