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CENTRAL VALLEY REGIONAL WATER QUALITY CONTROL BOARD <br /> INSPECTION REPORT <br /> 26 November 1990 <br /> DISCHARGER: CITY OF MANTECA WASTEWATER TREATMENT PLANT <br /> LOCATION & COUNTY: 2450 W. Yosemite, Manteca, San Joaquin County <br /> CONTACT(S) : Warren Shannon, WWTP Supervisor <br /> INSPECTION DATE: 20 November 1990 <br /> INSPECTED BY: Alexander MacDonald, Wayne Pierson <br /> ACCOMPANIED BY: Warren Shannon <br /> FACILITY DESCRIPTION: <br /> The Manteca wastewater treatment facility is permitted to discharge up to 5.75 million <br /> gallons per day (mgd) and is looking to expand to a treatment capacity of 6.95 mgd. <br /> Currently the facility is processing approximately 5.0 mgd. The facility consists of <br /> mechanically cleaned bar screens, aerated grit chambers, primary sedimentation tanks, <br /> biotowers, aeration tanks, secondary clarifiers, chlorination/dechlorination <br /> facilities, anaerobic digesters, and sludge drying beds. The effluent is applied to <br /> irrigation fields and to the San Joaquin River as conditions allow. Sludge is applied <br /> to the irrigation fields for utilization by crops. <br /> OBSERVATIONS AND COMMENTS: <br /> 1 . The purpose of the inspection was to become acquainted with the facilities and to <br /> discuss the operations with Mr. Shannon. <br /> 2. The plant appeared to be in good working order. Visual indicators at the various <br /> treatment units did not disclose any abnormalities. <br /> 3. The plant has had several violations of settleable matter over the last one and a <br /> half months. The initial cause of the violations was the discharge into the <br /> collection system of large amounts of solids from a pepper processor. The <br /> settleable matter contained a significant portion of red particles believed to be <br /> from the peppers. The discharge from the pepper processor has been curtailed, <br /> however, the settleable solids problem persists. Two consequences of the upset <br /> from the pepper waste are that the nitrifying rate is now 70%, where as before the <br /> upset it was 20%, and a related chlorine demand increase from 5 ppm to 10-15 ppm. <br /> Even with the increase in chlorine dosage the coliform count in the discharge has <br /> been elevated. If the coliforms in the discharge continues at the current <br /> concentrations the plant will be in violation of requirements for the month of <br /> November. <br /> Mr. Shannon and the engineer for the plant have tried lowering the MCRT to 1.5 <br /> days. This has only provided limited success in solving the problem. The plant <br />