A Location Selection Method for Wastewater Treatment Plants Integrating Dynamic Change of Water Ecosystem and Socio-Cultural Indicators: A Case Study of Phnom Penh

Abstract

The selection of reasonable locations for urban wastewater treatment plants (WWTPs) is significant in controlling water pollution. However, most current WWTP location selection models focus only on population density, industrial zone scale and geographic elements, while ignoring water pollution and local socio-cultural indicators. We propose a novel indicator system from RS/GIS data to select reasonable locations for WWTPs in Phnom Penh to avoid water environmental deterioration and harm to human health. The frequency of occurrence of water eutrophication is derived from time series RS data and reveals the degree of pollution of local water ecosystems, and is included as a demand indicator for the first time. In order to respect local socio-cultural customs, buffer zones for religious sites are included in the indicator system for the first time to fully determine the zones where construction of WWTPs is forbidden. Subsequently, WWTP locations are selected with the fusion of the minimized facilities number and maximum coverage models. The results demonstrate that the selected locations are all highly suitable and outside zones where construction is forbidden. The method proposed in the article provides a more comprehensive and scientific perspective for WWTP location selection.

Factors affecting the decision-making of appropriate sites for WWTPs

“…Distance from the population settlements (m) F1 (12,13,14,15,17,18,19,20,21,22,24,25,26,27,28,31) Distance from wells or groundwater (m) F2 (13,16,17,20,23,25) Distance from protected areas (m) F3 (16,19,20) Slope of site area % F4 (12,14,15,16,17,18,19,20,21,22,24,26,28,29) Distance from main and secondary roads (m) F5 (12,13,15,16,17,18,19,20,22,23,24,26,27,28,30,31) Distance from power transmission line (m) F6…”

“…Geological (Soil & Lithology) nature of the site F18 (16,17,19,21,11,12,15,19) Topography F19 (7,11,12,13,19) Distance from Railway network (m) F20 (17,19) Temperature F21 (17) Cost of owned the site ($) F22 Wind direction F24 (12,15) Distance from Airports locations (m) F25 (13,17) Location of water supply intake points (m) F26…”

“…As well as, identifying an appropriate site for a wastewater treatment plant (WWTP) can be a difficult and time-consuming endeavor for the relevant government agency due to the interplay of multiple geographical considerations. (7) There are many factors that can be identified from the literature and the experts that affect the selection of the optimal location for the WWTPs; consequently, it is difficult to consider all of them, so it is necessary to choose the most significant factors to be adopted by the planners and apply the tools to review the most suitable location to construct WWTPs. To determine the most significant factors, Relative Importance Index (RII) method that widely using to analyze the result of survey that has been built according to Likert scale.…”