Communal Wastewater Treatment Plants’ Effectiveness, Management, and Quality of Groundwater: A Case Study in Indonesia

Abstract

The Special Region of Yogyakarta is one of the provinces in Indonesia with a large number of communal wastewater treatment plants (CWWTPs). However, less than 40% of CWWTPS in the province are able to be operated well. This study aims to determine the effectiveness of CWWTPs concerning the quality of the surrounding groundwater. The research location was in Mlati, one of three sub-districts with the highest number of CWWTPs and highest population density in the province. Technical data were analyzed in a laboratory, including water quality of CWWTPs and groundwater quality. This study also analyzed non-technical data related to CWWTP management. These data were collected through in-depth interviews with CWWTP managers and users. The data were analyzed systematically, not only quantitatively but qualitatively. The distribution of water quality from CWWTP treatment and groundwater was mapped using inverse distance weighting (IDW). The results show that the CWWTP effluent meets quality standards for pH, temperature, COD, oil and grease, and ammonia. However, some CWWTPs fail to meet the quality standards for the TSS and E. coli parameters. Groundwater has an acidic pH, with ammonia, nitrite, and zinc parameters meeting quality standards, but oil and grease, COD, nitrate, and Pb concentrations exceed quality standards in several wells. This study indicates that the presence of CWWTPs is not correlated with the quality of groundwater due to the inefficiency of the CWWTPs, the unmet coverage area, and the conditions of sanitation facilities at the location.

Keywords

• CWWTPs
• groundwater
• inverse distance weighting
• water quality