http://www.eawag.ch/forschung/sandec/gruppen/sesp/hces/index_EN
[Accessed: 16.11.2010]
This website of SANDEC, the Department of Water and Sanitation in developing Countries at the Siww Federal Institute of Aquatic Science and Technology (EAWAG) provides more infor on the HCES approach. Check this site to find updates on the new HCES approach.