100 Acres of Sediment Laden Effluent Ponds Require Water Filtration System to Meet NPDES Discharge Outfall Limits

A Florida company processes phosphate rock that is then incorporated as a supplement in farm animal feed supplies.  The effluent from the process is discharged to a series of open surface impoundments to allow solids settling prior to discharge.  The ponds cover in excess of 100 acres of surface area and the water was released to a nearby canal under a NPDES discharge permit.  Over the years of constant production, the ponds have become heavily sedimented and the solids were beginning to carry over into their discharge outfall.  This condition caused them to exceed several discharge parameters limited by their discharge permit.  In a desire to improve environmental stewardship, they responsibly decided to begin to recycle the plant process water for reuse in order to reduce wastewater discharge volumes.

Initially they contracted with a water treatment contractor to provide R/O (reverse osmosis) filtration services; however, a separate local, established contractor was hired to pump the pond water to the R/O contractor at a project specification flow rate of 1000gpm at 50psi pressure.  The local pump contractor had limited capital assets to comply with the project specifications.  The pump contractor chose to utilize a hydraulic submersible pump from his inventory, while able to deliver the 1000gpm, could not come close to achieving 50psi of water pressure required by the R/O unit.  Additionally, by design, the hydraulic submersible pump was submerged in the shallow pond and sat just above the bottom of the earthen surface impoundments.  The position of the pump in relation to the pond bottom caused excessive amounts of scoured sediment to be sent to the R/O contractor’s bag filter system placed upstream of the R/O unit to prevent overloading the membrane filter system.  The disjointed effort was wreaking havoc on the whole system and little progress processing water was being realized.

The Ocala, FL Branch fielded the first frantic calls from the customer to determine if Rain for Rent could provide a pump to meet the project requirements.  After surveying the situation in an initial joint call, we recommended 2 x HH150SS pumps to satisfy the pumping specifications for the project.   Wisely, we recommended the dual set up to allow one pump to serve as primary, and the other as backup, to ensure adequate project redundancy.  Ocala’s secondary recommendation was to float the pump suction in order to minimize the disturbance of the pond bottom, with resultant reduction in the pumping of excessive amounts of sediment to the R/O system.

With the revised R/O wastewater processing system up and running according to the design specifications, a new project challenge cropped up.  The efficient flow volume began to overload the R/O contractor’s own bag filter system to the extent that they were changing bag filters several times per day.  After evaluating the existing situation, we recommended adding a sand media filtration unit to the process system.  2 x 48-4 sand media systems would provide system redundancy and comply with the project specifications.  The project operated successfully for several weeks and required only weekly change out of the bag filters.