SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD CENTRAL VALLEY REGION ORDER NO. NPDES NO. CA0081965 WASTE DISCHARGE REQUIREMENTS FOR STOCKTON COGENERATION COMPANY SAN JOAQUIN COUNTY The California Regional Water Quality Control Board, Central Valley Region, (hereafter Board) finds that: 1. The Stockton Cogeneration Company (hereafter Discharger) submitted a Report of Waste Discharge, dated 23 November 1999, and applied for a permit renewal to discharge waste under the National Pollutant Discharge Elimination System (NPDES). Supplemental information requested by the Board was submitted by the Discharger on 1 June 2000, 19 June 2000 and 24 August 2000. 2. The Discharger generates dechlorinated cooling tower blowdown together with other low volume wastes from its 49.9 megawatt (nominal 60 megawatt gross output) cogeneration plant which is discharged from Outfall 001 to North Littlejohns Creek in the NE 1/4 of Section 24, T1N, R6E, MDB&M (Attachment A), a water of the United States at latitude 37° 51' 14"N and longitude 121° 15' 35" W. Land disposal of effluent is maximized by discharging effluent at agronomic rates seasonally to an adjacent vacant industrial parcel (Attachment B) and to on-site irrigation. 3. Without the Stockton Cogeneration Company discharge,North Littlejohns Creek is an intermittent ephemeral stream fed largely by irrigation tailwater. The discharge now provides year-round flows in the creek downstream of Outfall 001. 4. The majority of the effluent discharged to North Littlejohns Creek at Outfall 001 consists of cooling tower blow down. The Discharger also utilizes an internal sump system to collect boiler blowdown, steam condensate, and miscellaneous machinery drains. The wastewater that collects in this sump is discharged periodically to the cooling tower system which is then discharged to Outfall 001. The Discharger also operates reverse osmosis (RO) and demineralization processes to treat boiler feed water. Most of the RO concentrate wastewater is combined and discharged with cooling tower blowdown to North Littlejohns Creek at Outfall 001. The remainder of the ROffw ohm concentrate is discharged to the City of Stockton Sanitary Sewer. The demineralization system is an ion exchange resin system and removes dissolved ions from the boiler feedwater after it is treated by the RO process. The regenerant waste from the demineralization system is neutralized in a sump prior to being discharged to the City of Stockton Sanitary Sewer along with all other sanitary and process wastewater from the facility.