Rhone-Poulenc AI Company Wastewater Treatment Plant Modification


Rhone-Poulenc AI Company
Institute, West Virginia



Rhone-Poulenc AI Company (R-PAIC) owned and operated an organic chemical manufacturing facility in Institute, West Virginia. In addition to R-PAIC, several other chemical manufacturers operated on the Institute site, and all discharged to the R-PAIC wastewater treatment system. The wastewater treatment system for the Institute site is approximately one mile from the chemical manufacturing site. Treated wastewater (clean water) is discharged via a National Pollution Discharge Elimination System (NPDES) permit to the Kanawha River.

The objective for modifying R-PAIC's wastewater treatment plant was to eliminate using three 10-million-gallon earthen lagoons for the activated sludge process.

Modification to the wastewater plant included the following.

  • Installed one mile of pipe from the chemical manufacturing process to the wastewater plant to deliver pure oxygen wasted from an existing nitrogen generating plant to the wastewater treatment system.
  • Converted two 3.2-million-gallon equalization tanks to variable-volume aeration tanks to provide equalization for stormwater run-off and activated sludge treatment.
  • Constructed a new covered 1-million-gallon load/pH equalization tank.
  • Installed pure oxygen aeration units (the aeration units were designed and patented by R-PAIC).
  • Installed a new chemical conditioning system replacing the existing batch system with a flow-through automated system.
  • Added a 330,000-gallon pure oxygen Autothermal Thermophilic Aerobic Digestion system which uses pure oxygen.
  • Installed a new effluent flow metering station.
  • Added a standby pure oxygen storage and delivery system.
  • Replaced electrical service, motor control center and instrumentation systems.


The project required significant coordination and sequencing to wastewater treatment to continue while modifying existing tanks and systems.



Aerobic Digestion System

R&W performed the conceptual and final design preliminary engineering work. As part of the preliminary engineering effort, cost estimates were developed for the proposed modifications. Following the preliminary design and cost estimate approval, R&W was retained to design the improvements.

R-PAIC performed a treatability study to confirm the feasibility for the activated sludge system's high temperature operation. Standard oxygen transfer efficiency studies were also performed on various aerator designs. R-PAIC used in-house staff to provide construction management services for the project implementation. R&W worked with R-PAIC staff to manage the project's construction. Major equipment purchases were bid and pre-ordered for installation by subcontractors. R&W prepared, bid and executed multiple contracts for the wastewater plant modifications.


Project Schedule/Cost

R-PAIC's proposed in-house estimates to eliminate the land-based treatment system exceeded $27,000,000. R&W worked with R-PAIC engineers to implement a solution which eliminated the lagoons and reduced odors and hazardous waste sludge production. This solution decreased annual operational costs by $500,000 and cost $8,000,000 in capital costs, thus saved R-PAIC $19,000,000.