Public works: Water
Provost & Pritchard is providing consulting services related to water quality concerns for a municipal water system, specifically with hexavalent chromium (Chrome 6). The agency has been impacted by a new state regulation because the level of Chrome 6 in all of the agency’s wells exceeds 10 ppb, the state’s maximum contaminant limit (MCL). Within a month of the regulation being proposed, Provost & Pritchard was retained to evaluate the problem and find a solution. The project includes continued engineering support related to assessing the impacts of the impending hexavalent chromium regulation on the agency’s water supply; evaluation of the existing water supply system; and serving as a liaison between the agency and regulatory agencies, water contractors, equipment suppliers, government representatives, and other interested parties.
The City of Fresno currently has two pumping Stations, PS 117 and 284 that are contaminated with PCE. PS 117 has been off-line since 2008 due to PCE levels exceeding the regulatory maximum contaminant level (MCL) while recent PCE levels at PS 284 have been below the MCL Both sites are too small to accommodate the addition of any wellhead treatment. Provost & Pritchard prepared an initial report that analyzed both sites and identified that granular activated carbon (GAC) and air stripping were both the best available treatment technologies. After the initial submittal of the report, the City directed Provost & Pritchard to investigate and provide design criteria for removal of PCE using air stripping. A second report was prepared which defined the treatment plant design parameters and developed schematic site plans for review by the City. The site plans included in the report will form the basis for the subsequent preparation of construction bid documents (i.e. plans and specifications) that will be used to bid and construct the recommended improvements.
Provost & Pritchard has prepared Mitigation Feasibility Study to address 1,2,3,-Trichloropropane (TCP) contamination for public water agencies and cities throughout the state of California. The studies typically include an evaluation of alternative methods of mitigation and treatment, an evaluation of water quality, an assessment of existing well sites, development of schematic treatment site layouts, and preparation of capital and Operation & Maintenance cost opinions.