Filtration Project a Big Success!

An old sewer pipeline in the historic district of a downtown area in a California city was scheduled for replacement due to damage sustained over the years.  The construction company contracted by the city designed a rehabilitation project around the historic railroad and close to the downtown river area. 

However, due to approximately six-foot tidal influences, water filled an old storm drain and infiltrated into the ground affecting the surrounding areas where the pipeline was being replaced.  In addition, preexisting utilities were in close proximity to the construction site.  Old gravel around the utility site allowed water to seep through the bedding, which increased the amount of fluid to be dewatered.

Rain for Rent was originally contacted to provide a sewer bypass system.  However, the water table problem created a need for dewatering and filtration solutions.  Preexisting VOCs as well as sediment in the water required filtration and treatment throughout the project. Prior approval was required from the California Water Quality Control Board to discharge treated water into the sewer and storm drain.

Rain for Rent's Engineering Department designed a 300-foot long filtration system to filter out sediments, VOCs and hydrocarbons. Rain for Rent provided Power Prime™ pumps, tanks, filtration equipment and Spillguards, as well as maintenance and operation of the system. 

The water was pumped through two Rain for Rent weir tanks injected with an organic polymer to help clarify the water and enhance filtration.  From the two weir tanks, the water was pumped through a 48-4 sand media filter into 10 PV 2000-pound Granular Activated Carbon (GAC) pressure vessels for treatment of known contaminants.

The water was then discharged into an open-top, 18,000-gallon tank and two 21,000-gallon bi-level tanks for storage and sampling. A DV-100, 4-inch pump discharged the first 50 GPM of filtered water that was allocated to the sanitary sewer and up to 450 GPM was discharged into the storm drain.  A BF200 filter was used to polish the water prior to discharge.

Rain for Rent provided turbidity testing at frequent intervals throughout the process to meet the discharge requirements of the city and the California Water Quality Control Board.

In addition, Rain for Rent personnel are on site as early as 4:00 a.m. daily to dewater, prepare the job site and monitor the system, which runs 8-12 hours a day, 5-6 days a week.  The job is projected to continue throughout the year.