However, satisfying regulatory requirements with chlorination practices had proven difficult and resulted in a number of fines. The chemical-free solution was to upgrade the treatment system to tertiary filtration and ultraviolet light disinfection. With filtration accomplished using cloth disk filters (CDF), the Manteca WQCF represents one of the earliest installations of CDF in California and one of the largest installations in the western US.
The new wastewater treatment system came on-line, with no disruption of existing service, a full two months ahead of the regulatory deadline. The project received a 2010 Merit Award in the American Council of Engineering Company’s (ACEC) California Engineering Excellence Awards competition.