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WASTE DISCHARGE REQUIREMENTS -2- SIMPSON LEE PAPER COMPANY RIPON MILL SAN JOAQUIN COUNTY 5. The Discharger also operates an electric cogeneration plant. Water supplied to the cogeneration plant is treated by a reverse osmosis (RO) filtration unit. The 4-stage RO process removes 95 percent of the dissolved solids from the water; the desalinated water is used to make steam. The steam can then be recycled without particles clogging the system and damaging the generator turbine blades. The RO effluent goes directly to Pond 2. 6. The Discharger, in an effort to abate odors emanating from its ponds, proposes to convert the inactive sludge pond (see Attachment B which is hereby made part of this Order) to an aeration basin for secondary treatment of mill effluent. Inert dewatered sludge from the inactive sludge pond has been placed on 50 acres and disced into the top eight inches of soil as a soil amendment. 7. The discharge has resulted in elevated levels of total dissolved solids (TDS) beneath the disposal areas. Wastes discharged to percolation areas in the past had TDS levels as high as 2500 mg/l . 8. Regional Board staff determined that past waste discharges were classified as "designated wastes" under Title 23, California Code of Regulations, Division 3, Chapter 15. 9. Subsequent to the Regional Board's determination that the waste was designated, the Discharger has completed or proposed three projects in order to reduce effluent total dissolved solids (TDS): a. The Discharger has reduced the alum consumption by making changes in the manufacturing chemistry. This change has reduced the effluent TDS to 1400 mg/l . b. The Discharger plans to replace the cogeneration water softener brine regeneration system with a weak-acid cationization (WAC) system. This change will result in a reduction of TDS below 1200 mg/l in the discharge to Pond 2 from the cogeneration facility. C. The Discharger plans to replace its three existing water supply wells, which are screened in both the semi-perched zone and deeper zones. The Discharger will replace these well with four water supply wells screened only in the deep zones. The Discharger believes this will reduce the TDS in their process water to 1100 mg/l and eliminate the cross-contamination of salt into the deeper zones from the semi-perched zones. 10. Background water quality at the site is difficult to ascertain due to a plume of pollutants to the north of the site, which originates from the Nestle facility. Also, to the west of the site, the City of Ripon discharges both domestic and industrial wastewater to percolation ponds. Recharge from the Stanislaus River is of very high quality.