SITE INFORMATION AND CORRESPONDENCE 1980-1999

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WASTE DISCHARGE REQUIREMENTS ORDER NO. 5-00- • -3- CITY OF LODI WHITE SLOUGH WATER POLLUTION CONTROL PLANT SAN JOAQUIN COUNTY 9. Biosolids are treated by anaerobic digestion and stored in sludge stabilization ponds. Wet biosolids are currently handled by periodic blending with reclaimed water and distributed via a ditch to fields for application by flood irrigation. 10. The reclaimed water and biosolids are used for surface irrigation of fodder, fiber, or seed crops, which are not used(directly or indirectly) for human consumption. Also, unchlorinated domestic effluent is used as cooling water in a closed loop system at a cogeneration facility, and for mosquito fish rearing in ponds adjacent to the treatment plant. 11. The Board adopted a Water Quality Control Plan, Fourth Edition, for the Sacramento and San Joaquin River Basins (hereafter Basin Plan). The Basin Plan designates beneficial uses, establishes water quality objectives, and contains implementation programs and policies to achieve water quality objectives for all waters of the Basin. These requirements implement the Basin Plan. 12. The beneficial uses of Dredger Cut and the Sacramento-San Joaquin Delta downstream of the discharge as identified in Table U-1 of the Basin Plan are municipal, industrial, and agricultural supply; body contact and noncontact water recreation; aesthetic enjoyment; navigation; and preservation and enhancement of fish, wildlife and other aquatic resources. 13. The beneficial uses of the underlying groundwater are municipal, industrial, and agricultural supply. The Discharger has installed seven groundwater monitoring wells and monitoring of the groundwater will continue, under this Order, to provide protection of the beneficial uses. This Order requires additional monitoring wells to be installed to evaluate underlying groundwater quality on any additional acreage, or as needed on existing acreage. 14. The Discharger has completed an expansion of its secondary domestic waste treatment capacity to 8.5 mgd, but the effluent flow rate allowed by this permit has not been increased beyond 7.0 mgd due to concerns regarding the impact of the discharge on dissolved oxygen concentrations in the receiving water. The previous permits have required compliance with the dissolved oxygen objective at the point where Dredger Cut meets White Slough. However, this does not protect Dredger Cut. Receiving water monitoring data collected from January 1997 to May 1998 shows that, at the current discharge rate of less than 6 mgd, corresponding to a BOD loading up to 532 lb/day, the dissolved oxygen in Dredger Cut does not meet the Basin Plan objective for dissolved oxygen of 5 mg/1 in 39% of samples collected when discharge was occurring, whereas it is usually met further downstream below the confluence with Bishop Cut and White Slough. The discharge is causing or contributing to the low dissolved oxygen conditions. Studies completed to date indicate that the discharge of 8.5 mgd of secondary- treated effluent may cause violations of the dissolved oxygen objective to also occur in White Slough and, to a lesser extent, in Bishop Cut. This Order includes more stringent effluent limits for BOD than were imposed in the past. This alone will not achieve compliance with the dissolved oxygen objective in Dredger Cut. Therefore, it also requires the Discharger to maximize land disposal of effluent, and prohibits discharges when dissolved oxygen