Rhone-Poulenc AI Company
Wastewater Treatment Plant Modification

Client

Rhone-Poulenc AI Company
Institute, West Virginia

Situation

Rhone-Poulenc AI Company (R-PAIC) owned and operated an organic chemical manufacturing facility located in Institute, West Virginia. In addition to R-PAIC, several other chemical manufacturers operated on the Institute site, all of which discharge to the R-PAIC wastewater treatment system. The wastewater treatment system for the Institute site is located 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 of the modifications to the R-PAIC wastewater treatment plant was to eliminate the use of three 10 million-gallon earthen lagoons used for the activated sludge process.

Modification to the wastewater plant included the following:

• Installation of one mile of pipe from the chemical manufacturing process to the wastewater plant to deliver pure oxygen that had been wasted from an existing nitrogen generating plant to the wastewater treatment system
• Conversion of two 3.2 million gallon equalization tanks to variable-volume aeration tanks in order to provide both equalization of storm water run-off and activated sludge treatment
• Construction of a new covered one million gallon load/pH equalization tank
• Installation of pure oxygen aeration units (the aeration units were designed by R-PAIC and patented)
• Installation of a new chemical conditioning system replacing the existing batch system with a flow-through automated system
• Addition of a 330,000-gallon pure oxygen Autothermal Thermophilic Aerobic Digestion (ATAD) system utilizing pure oxygen
• New effluent flow metering station
• Addition of a standby pure oxygen storage and delivery system
• Replacement of electrical service, motor control center (MCC), and instrumentation systems

The project required significant coordination and sequencing to allow for the continued treatment of wastewater while modifying existing tanks and systems.

Solution/Services

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

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

Project Schedule/Cost

The proposed in-house estimates at R-PAIC to eliminate the land-based treatment system exceeded $27,000,000. R&W worked with R-PAIC engineers to implement a solution that eliminated the lagoons, reduced odors, reduced hazardous waste sludge production, and decreased annual operational costs by $500,000 for a capital cost of $8,000,000.