Effectiveness of communal wastewater treatment plant in peri-urban Yogyakarta, Indonesia, for Escherichia coli removal

Abstract

Yogyakarta Special Region, one of Indonesia’s provinces, has many communal wastewater treatment plants (CWWTPs). However, less than 40% of the province’s CWWTPs are operationally viable. Based on data from the Environmental Agency of Sleman Regency, the physical and chemical parameters of approximately 163 CWWTPs were evaluated. Their biological characteristics, however, still need to be understood. This study aimed to investigate the efficacy of CWWTPs in terms of biological parameters, specifically total Coliform and Escherichia coli (E. coli) concentrations in the observed CWWTPs. Five CWWTPs were used as study sites, namely IPAL Manunggal Pringgodani Sejati, IPAL Bakti Warga, IPAL Tambakrejo Bersih, IPAL Nologaten Bersih, and IPAL Andum Roso, which were classified as extremely high and high sanitation risk areas. The total Coliform and E. coli concentrations were determined using MPN techniques based on APHA 9221 (2017). The study found that the E. coli removal effectiveness of the CWWTPs in the very-high sanitation risk areas, namely IPAL Manunggal Pringgodani Sejati, IPAL Bakti Warga, and IPAL Tambakrejo Bersih, was 49%, 18%, and 83%, respectively. Furthermore, in high sanitation risk regions, such as IPAL Nologaten Bersih and IPAL Andum Roso, the CWWTPS were 17% and 73%, respectively. Total Coliform concentrations at all CWWTPs were below the standard limit set by Permen LHK No 68 and the EPA. The findings of this study will help to improve understanding of the WWTP process for E. coli elimination, which will, in turn, help to improve CWWTP performance.