The city administration says it is working with the central government to build a sewage tunnel system that will channel household liquid waste to a plant that will recycle it into raw water.
Governor Fauzi Bowo said the government would use a Rp 3.8 trillion (US$412.5 million) loan from the Japan International Cooperation Agency (JICA) for the initial construction of pipes and the plant.
"We chose a foreign loan because the private sector cannot afford to fund an infrastructure project of this scale," he said after meeting with representatives from the Public Works Ministry at City Hall on Friday.
The city will foot Rp 700 billion of the total cost.
Susmono, the director of environmental health division at the Public Works Ministry, said the plant would turn liquid waste, including from septic tanks, kitchens and bathrooms, into raw water before flushing it away into nearby rivers or dams.
"Houses that are connected to the sewage system will have dry ditches. The ditches will only channel rainwater," he said.
Fauzi said the city and the government would need to review a master plan of the first phase of the project, which is expected to start in the middle of 2011 be operational by 2020.
Fauzi said in the first stage of the project, a team from the city and the government would construct the central zone project that would run from Setia Budi in Central Jakarta to a plant in North Jakarta.
He said the team had not decided on the plant's location, saying they were still considering the options of an area near Pluit dam and Muara Angke, North Jakarta.
The central zone would use a 1.8-meter diameter pipe from Setia Budi that would be pumped to the plant, he said.
"The first phase of the project can only serve 700,000 people, or some 10 percent of the capacity," Fauzi said.
Despite the small capacity, he said the construction of the main pipes would be the milestone of the project, as it would make construction of the rest of the system easier.
The next project would be the northwest zone, running from Gunung Sahari in Central Jakarta to Sunter in North Jakarta. The southwest zone would run from Palmerah to Kebon Jeruk in West Jakarta, he said.
Fauzi added that he was optimistic that by 2030, the capacity of the sewage system would reach 25 percent after these two zones were completed.
Ahmad Haryadi, the deputy governor overseeing city spatial and environment planning, said the team had not calculated the cost for the whole project, including the second phase.
"The easiest calculation was the central zone," he said.
Susmono said the tunneling sewage system was a national project started in 15 cities.
He said the pilot project for the system was being applied in 11 cities, including Jakarta, Bandung in West Java, Medan in North Sumatra, Yogyakarta, Surakarta in Central Java, Banjarmasin in South Kalimantan and Denpasar in Bali.
In Jakarta, a sewage processing plant, part of the project, is located in Setia Budi, covers only the neighboring area.