Analysis of Total Coliform in Wastewater Outlet of Laboratory WWTP Using Most Probable Number (MPN) Method

Abstract

This study was conducted at the UPTD Environmental Laboratory of the Environmental Service Office of West Sumatra Province to evaluate the microbiological quality of wastewater discharged from a laboratory-scale Wastewater Treatment Plant (WWTP). The purpose was to analyze the presence of Total Coliform bacteria using the Most Probable Number (MPN) method. Water samples were collected from the WWTP outlet and analyzed using a three-stage MPN procedure, involving Lauryl Tryptose Broth, Brilliant Green Lactose Bile Broth, and EC Broth media. The result showed a Total Coliform value of 930 MPN/100 mL, which was below the maximum limit set by Indonesian environmental regulations (3,000–10,000 MPN/100 mL). This indicates that the laboratory’s wastewater treatment system functions effectively in reducing microbial contaminants. Routine microbiological assessments are essential to ensure continuous compliance and to prevent environmental pollution.