The Use of Chemically Enhanced Primary Treatment (CEPT) in Honduran Imhoff Tanks

Imhoff tanks are a common primary treatment technology in Honduras, but increased wastewater production from upstream communities has caused facilities to reach levels beyond their designed capacities. Chemically enhanced primary treatment (CEPT) has the potential to improve the performance of Imhoff tanks by increasing the efficiency of solids removal with increased loading. Also, the addition of chemical coagulants to influent wastewater can potentially provide higher solids removal rates than the existing removal rates.The municipality of Las Vegas, Honduras is currently experiencing this challenge. The feasibility of CEPT to Imhoff tanks in Las Vegas was tested through bench scale and pilot testing. The results indicate that in this case, the system was so severely overloaded that CEPT is not an appropriate option for providing expanded wastewater treatment to Las Vegas. This example can possibly serve as a starting point for efforts to adopt CEPT in primary treatment in developing countries.