A community-owned sewer

Submitted by pcastillo on October 13, 2009 - 9:43am

Ashoka-Lemelson Fellow Agus Gunarto designed and implemented a replicable Community-Based Sewer System (CBSS) in Indonesia. A series of 100mm (4”) plastic collecting pipes laid beneath footpaths or below existing drains connect the mini-sewage systems to a network of houses. Concrete treatment plants with plastered brick tanks and chambers are located at the lowest point in the system, so the flow is utterly dependent on gravity. Wastewater is progressively filtered through a small anaerobic septic tank and then a series of four small aerobic holding tanks (two square meters each). Treated water is then released into the river or local watercourse. A plant of four tanks takes up only a small area of land: a plant for 200 households needs an area of only about four by six meters.

The system, locally also known as the “Tanki AG” (or “System AG”) from the initials of Agus Gunarto, is set up and maintained by the local community. Community ownership, combined with funds obtained from external donors and the government, makes the CBSS an affordable and income-generating enterprise. The families connected to the system now have latrines in their homes, clean well water, and a community environment that has radically changed for the better. Nothing is wasted in the process: sediment is sold as fertilizer; water hyacinths, which are used to reduce odor in the first two tanks, are dried and chopped up and mixed with corn as chicken feed since they make egg shells stronger; and finally, the relatively clean water in the last tank is used to breed catfish, which creates an extra source of income. The effects on the communities that have undertaken Agus' project are dramatic. In one area, it has been the catalyst for a movement to improve the whole area: pathways are paved (over the sewerage pipes), rubbish collection is organized, and the general cleanliness of the area is significantly improved.

If you are interested in the technical details of the system, be sure to check out MIT's case study on Agus's project.

Photo by: flickr/joem500