Irsyan Hasyim, Jakarta – Jakarta's Department of Environment, in cooperation with the Faculty of Engineering's Institute of Technology at the University of Indonesia (LEMTEK UI), conducted an inventory of pollutant loads in five major rivers: Ciliwung, Cipinang, Sunter, Cideng, and Grogol.
The study found that treatment of domestic black water (sewage from toilets containing feces, urine, and organic waste) was relatively effective, with treatment rates between 95 and 98 percent.
In contrast, grey water waste, which includes wastewater from washing, bathing, and cooking, is mostly discharged untreated into the rivers. The proportion of untreated grey water remains high: 95 percent in Ciliwung, 91 percent in Cipinang, 87 percent in Sunter, 62 percent in Cideng, and 80 percent in Grogol.
"This shows that our domestic wastewater management system has not fully addressed all areas," said LEMTEK UI researcher Mochamad Adhiraga Pratama in a statement released on Friday, August 8, 2025.
The inventory also highlighted that river pollution is worsened by activities from traditional markets and micro, small, and medium enterprises (MSMEs), as well as slaughterhouses processing poultry and livestock, many of which lack wastewater treatment systems.
Iwan Kurniawan, Head of the Bureau of Development and Environment at the Jakarta Regional Secretariat, stressed that rivers play a crucial role in both the ecology and social life of Jakarta's residents.
He said the provincial government is actively working to improve water quality through programs such as Trash-Free Jakarta, Jakarta Waste Awareness, River Naturalization, Mud Clean-Up, strengthening pollution source monitoring, and enforcing Environmental Management Statements (SPPL).
"This water quality challenge cannot be solved by one party alone," Iwan said. "Real collaboration between government, communities, businesses, and academics is essential to make Jakarta's rivers cleaner, healthier, more resilient, and competitive globally."
Asep Kuswanto from Jakarta's Department of Environment noted that besides domestic sources, MSMEs are the largest contributors to river pollution. Many MSMEs, including workshops, laundries, eateries, printing shops, and slaughterhouses, are required to comply with SPPL regulations but often lack proper wastewater treatment.
"Although small in scale, without adequate treatment systems, these businesses significantly impact water pollution," Asep said. He also promised to intensify supervision and support down to the sub-district level, describing this as a concrete step to address pollution at its source.