SITE INFORMATION AND CORRESPONDENCE

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• INFORMATION SHEET SIMPSON PAPER COMPANY, RIPON MILL SAN JOAQUIN COUNTY The Simpson Company (owned by Simpson Timber Company, Seattle, Washington) oper- ates a paper mill located within the city limits of Ripon, San Joaquin County. The Ripon Mill is an nonintegrated paper mill which manufactures several grades of fine papers from purchased pulp. The mill 's maximum daily production rate is 187,000 lbs (84,898 kgs) of paper. Waste Discharge Requirements Order No. 77-286, NPDES No. CA0004006, adopted by the Board on 16 December 1977, prescribes requirements for the discharge of industrial wastewater and stormwater runoff from primary and secondary treatment facilities at the mill . The Simpson Company, Ripon Mill , has applied for the reissuance of the forementioned NPDES permit which expired on 1 December 1982. The Ripon Mill proposes to intermittently discharge a maximum 0.5 mgd (21.9 1/sec) of industrial wastewater from secondary treatment facilities into the Stanislaus River. In addition, the mill will discharge a maximum 1.8 mgd (78.9 1/sec) of combined industrial wastewater and stormwater runoff from primary and secondary treatments to 90 acres (36.5 ha) of company owned property, 35 acres ( 14.2 ha) of which are dedicated for effluent disposal and 55 acres (22.3 ha) designated as USDA approved agricultural irrigation. Prior to July 1975, the Ripon Mill discharged to the Stanislaus River continuously or intermittently. Since July 1975, they have been able to contain all wastewater on land . The Simpson Paper Company would like to retain the option to discharge to the river in case they resume a seven-day per week operating schedule or install a second paper machine. If it becomes necessary to discharge, a floating aerator will be installed in the final stabilization pond. The discharge would not commence until all the requirements prescribed in this Order are be met. The proposed waste discharge requirements reflect the more stringent of: the effluent limitations proposed by the Environmental Protection Agency (40 CFR Part 430 Subpart R, NI Fine Papers Subcatagory) representing application of best practicable control technology currently available; the existing effluent limita- tions contained in Order No. 77-286; the description of effluent quality contained in the Report of Waste Discharge submitted by the Discharger; and water quality objectives contained in the Water Quality Control Plan for the San Joaquin and San Joaquin-Sacramento Delta Basins. The daily maximum BOD and Suspended Solids effluent limitations for discharge 001: discharge to the Stanislaus River were based on retaining the maximum allowable concentrations from Order 77-286 of 60 mg/l and using the proposed maximum flow of 0.5 mgd to obtain the mass emmission rates of 250 lbs/day. The Report of Waste Discharge described the proposed BOD and Suspended Solids concentrations in the river discharge as 60 mg/l maximum and 45 mg/l daily average. The 45 mg/l average values are included in the proposed requirements as limitations for 30-day average