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LARGE SCALE DE-WATERING PROJECT
A Construction Company in the San Francisco Bay Area encountered an urgent de-watering project. The Company needed to de-water a 14 million-gallon pond in order to construct a marina. The developer had anticipated pumping the water over a dike and into a tidal creek. Construction was scheduled to begin when the developer discovered that this method would not be acceptable to the water board. The regional water board required it be filtered to minimize sediment pollution. Surrounding groundwater wells showed the potential for diesel contamination. This meant the system also needed Granular Activated Carbon to remove any diesel fuel.
Clear Creek Systems was called in to provide a rapid de-watering system that addressed both sediment and diesel contamination. The Contractor required a 1,000 gpm system on line within a week from receipt of a Notice To Proceed.
Mobilization and setup of a 1,000 gpm system requires a lot more than the sediment, filters and carbon. The site had to be evaluated for system layout, pad layout, access, proper pump sizing to match flow and pressure needs, ancillary piping, backwash tanks and low impact discharge system. Clear Creek Systems worked with the permitting agency to obtain acceptance of a low carbon residence time due to the low level of potential diesel contamination thus eliminating significant costs of the system. Even with the low residence time, 20,000 lbs. of Granulated Activated Carbon was required. After startup, Clear Creek Systems provided continuing monitoring of the system.
The system utilized a High Head Pump, three PF-750 Sediment Filters units, a 20,000 lb. Carbon Vessel, two 21,000 gallon storage tanks and flow meter. Clear Creek System’s proprietary 0.5 micron CS Series Filter Cartridges were used for maximum filtration of the fine sediments.
CCS’ system monitors insured the system operated as required and made adjustments as lower water levels increased the sediment levels entering the system. The monitors also maintained logs needed to compile reports required by regulatory agencies.
After the 14 million-gallon pond was de-watered, The second phase of the project began. Due to its proximity to the tidal bay, the pond was recharging at a rate of 140-160 gpm. The contractor needed to maintain a low water level in order to build the marina perimeter shoring. Clear Creek Systems quickly scaled down the system to provide the same treatment standards at a 200 GPM rate.
Over the entire project more than 25 million gallons were treated and discharged into the bay at a fraction of the alternative costs. Clear Creek System responded to all of the client’s needs on an extremely tight timeline and within the proposed budgets.
