The Role of Phnom Penh’s Wetlands in Sustainably Treating Sewage Discharges to the Mekong/Bassac/Tonle Sap River System

The city of Phnom Penh, Cambodia, relies on a system of natural wetlands to treat much of its sewage before it reaches the Mekong/Bassac/Tonle Sap river system, but to accommodate the city’s rapid growth, infilling of the wetlands has begun. As the city’s population increases, its ability to treat waste is coming under increasing pressure. This presentation describes an ongoing study that is characterizing the levels of pollutants entering and leaving the largest treatment wetland, Boeng Cheung Ek, in order to assess the efficiency of the wetland in treating waste. In addition to the sampling, the sewer system and wetland is being modeled using PCSWMM to help make recommendations for optimizing treatment. The wetland also is used for fishing and growing crops that includes extensive fields of morning glory. The study will examine possible health implications for the communities living on and using the wetlands and includes an education program to minimize health risks. This research effort involves faculty and students from Royal University of Phnom Penh, Asian Institute of Technology, Chiang Mai University, and Buffalo State, State University of New York, staff from a local NGO, Resource Development International, and staff from the Ministry of Environment. The importance of multidisciplinary, multisector collaboration and capacity building is emphasized.