Unravelling the FOG Deposit Sources Characteristic in the South Jakarta City Wastewater Network

Environmental Engineering Study Program, Department of Civil Engineering, Faculty of Engineering, Universitas Indonesia, Depok, Indonesia

^* Corresponding author: nd.maulidiany@ui.ac.id

Abstract

DKI Jakarta is the largest wastewater contributor in Indonesia, where 75% of it comes from domestic activities. Typically, effluent will enter the river via a system of wastewater pipelines. Numerous wastewater networks have been observed to have FOG deposits (FD), particularly in South Jakarta. FD is an accumulation of oil and grease in sewerage systems that results in blockages and gas accumulation, leading to explosions in closed networks. Despite the impact being well known, there are currently very few studies that focus on Indonesia’s FD, particularly FD in Jakarta’s centralized wastewater network. This study aims to analyse the main sources and characteristics of wastewater that forms FD. Samples from two locations were used to compare the conditions of sewerage without FD and those with FD (A and B, respectively). Results showed that Padang restaurants and catering are the main sources of pollutants affecting FD formation. The FOG concentration in sample B was 2x10⁷ times higher than in sample A, while the TSS concentration was 1.8x10⁴ times higher. The dominant free fatty acid (FFA) in sample B was palmitic acid (51%), resulting in a dense precipitate structure and composition.