Engineered wetlands for wastewater treatment in Sarawak

Abstract

Demand for improved receiving water quality requires efficient domestic wastewater treatment systems in the state of Sarawak in Malaysia. Currently, most wastewater in Sarawak is treated primarily via individual septic tanks (ISTs), which is a traditional on-site and low level treatment technology. Engineered wetlands are one of the most promising treatment systems for residential areas in Sarawak due to its sustainability, simple operation and maintenance and cost effectiveness. A viability study is presented here to study engineered wetlands as a possible domestic wastewater treatment system in residential areas in Sarawak. From the study, the construction, operational and maintenance cost of engineered wetlands is higher than individual septic tanks, but lower than that of electro-mechanical treatment systems. Although the land use of engineered wetlands is also larger than ISTs, they are capable of achieving Standard A of the Malaysian Environmental Quality Act 1974, which show potential for achieving higher treatment effectiveness compared to ISTs. From the survey, 50% of the respondents, which include housing developers, are unwilling to pay extra costs for centralized wastewater treatment. Engineered wetlands require larger land area which is costly in urban residential areas such as Miri City. 95% of the respondents think that it is more urgent to treat stormwater compared to wastewater, since the public is more concerned with flooding problems. 77% of the respondents support the concept of engineered wetlands provided the constraints are identified and justified. To conclude, from this survey engineered wetland is feasible as a sustainable wastewater and stormwater treatment option in Sarawak, with the support of local authorities and various parties.