HTI OsMem™ Closed Loop Hybrid FO Wastewater System

Industry: Landfill Leachate
Client: Coffin Butte Regional Landfill

Application

Dewatering of toxic landfill leachate from municipal landfill project, concentration and solidification of contaminated retentate, and discharge of purified permeate water for irrigation meeting NPDES standards. The hybrid system consists of Forward Osmosis (FO) primary pretreatment driven by 9% Sodium Chloride osmotic draw solution, diluted by FO to 5%, then polished and reconcentrated in a closed loop by high pressure Reverse Osmosis (RO). The volume reduction from FO is 90+% with the retentate going to solidification with Portland Cement which was returned to the landfill. The clean permeate from the RO system was discharged to a wetland.

Equipment

HTI OsMem™ Closed Loop Hybrid FO Wastewater System

Typical Process Data:

System Flow Rate: 25,000 GPD
System Pressure: FO < 20 psi | RO %7e 1100 psi
Draw Solution: 9% NaCl diluted to 5%
Fluid: Raw Landfill Leachate - high in dissolved and suspended solids
Operating Cost: $.05 / Gal

Findings

System Description

The HTI OsMemTM Closed Loop Hybrid FO Wastewater System uses plate and frame cassettes of HTI’s proprietary OsMemTM FO membrane. The system has 2500 square meters of FO membrane and produces a flux rate of 25,000 gallons per day. Prefiltration to 100 microns is accomplished using a bag filter system. The FO system is cleaned on a weekly basis. The RO system uses high pressure seawater spiral wound elements with a nano-membrane brine booster. To achieve permeate discharge conductivities of less than 10 micro Siemens, RO polishing is used.

Summary

The HTI OsMemTM Closed Loop Hybrid FO Wastewater System meets tough NPDES discharge regulations and facilitated Coffin Butte Landfill’s requirements for acquisition of permitting to treble the size of the landfill operation.

The HTI OsMemTM Closed Loop Hybrid FO Wastewater System meets tough NPDES discharge regulations and facilitated Coffin Butte Landfill’s requirements for acquisition of permitting to treble the size of the landfill operation.