Cerrudo Services, as sole subcontractor to Alutiiq International Solutions, provided environmental service work at 30 reservoirs. Cerrudo cleaned and disinfected the water reservoirs and ensured they are ready for use. The reservoir structures are both in-ground and above ground structures. Prior to cleaning, Cerrudo performed a reservoir/tank inspection providing information to identify and evaluate current and potential water quality problems. Both interior and exterior inspections were employed to assure the reservoir/tank’s integrity, security and high water quality. The inspection included visual inspections of structural and non-structural members, coverings, pipe and drains, and equipment and components.
The reservoir surfaces to be cleaned and disinfected varied from concrete, steel, polypropylene lined and redwood. Cerrudo developed a cleaning schedule with the order and time frame in which the reservoirs were cleaned. The work required an approved Confined Space Entry Plan prior to performance of the work. Although the reservoirs are easily accessible, most are located in remote areas.
Cerrudo removed all sediment from the reservoirs, and hauled and disposed of the sediment at 3-Mile Pit near the Base. Rinseate (pressure washing by-product) was disposed at the nearest Waste Water Treatment Plant.
Cerrudo used Chlorination Method 2 when chlorinating the reservoirs. The chlorination time requirements were coordinated with the filling of the reservoir/tank by the Base Water Department. The reservoirs were disinfected with a chlorine solution of at least 1,000 mg/l, and allowed to set a minimum of 24-hours after application of the chlorine solution before being filled.