A partnership between General Electric and Hitachi, GEH provides products and services to the nuclear energy industry and operates a nuclear reactor and fuel assembly manufacturing and spent fuel rod cleaning facility at the company’s Wilmington, NC, headquarters. Due to the size and nature of the facility, GEH has two on-site wastewater treatment plants: a 75,000 GPD sanitary wastewater treatment plant that handles the domestic wastewater produced by personnel, and a separate treatment plant that handles the industrial wastewater from the facilities processing operations. The existing sanitary wastewater treatment plant needed to be upgraded to better handle flow differences between shifts and between weekday and weekend operation, as well improve the effluent quality, so GEH partnered with WithersRavenel to develop the renovation design.
The improvements consisted of the addition of mechanical screening and fine screens to remove debris prior to downstream treatment, the addition of a 100,000 gallon equalization tank to dampen the diurnal and shift work flow patterns, conversion of the conventional aeration basin to a bio-reactor with anoxic, anaerobic and aeration zones with mixed liquor returns, the addition of a membrane filtration unit and ultra-violet disinfection. GE manufactures the Zeeweed Membrane Reactor which produces an effluent with almost non-detectable TSS levels. Therefore, the effluent is free of protozoa and cysts, and has significantly reduced bacteria and viral counts, providing an effluent meeting the most stringent regulations. Coupled with the improvements to the bio-reactor and the UV disinfection the treated effluent is well beyond the North Carolina reclaim water standards.
The purity of the effluent allowed WithersRavenel and GEH go one step further and obtain a conjunctive reuse permit, which allows GEH to capture the discharge from the sanitary wastewater treatment plant in reclaimed water storage tanks and pump it into the site’s water recycling system virtually eliminating the NPDES discharge. This system supplies the cooling water towers for the site industrial processes. By adding this source of recycled water, GEH was able to reduce reliance on the need for groundwater to feed the cooling water towers, which not only reduces the site’s direct environmental impact on the water table but also decreases its indirect impact by requiring fewer chemical additives to prevent scale buildup in the cooling towers. In addition, the conjunctive use permits will allow GEH the option to send recycle water through the site reverse osmosis plant where water is treated for use in the nuclear fuel rod cleaning process.
Overall, the combination of facility and operational improvements allows GEH greater flexibility and self-sufficiency in handling both its sanitary wastewater treatment and facility industrial water consumption.