|
From YubaNet.com Regional
1. Waste Discharge Requirements Order No. R5-2002-0088 Receiving Water Limitation G.5 states: "Receiving Water Limitations are based upon water quality objectives contained in the Basin Plan. As such, they are a required part of this permit. The discharge shall not cause the following in the receiving water:" "5. Fungi, slimes, or other objectionable objects." The treated effluent adds nitrate, organic nitrogen, phosphorous, and orthophosphate to the South Yuba River. These nutrients are known to promote algae growth. There was algae growth below the effluent discharge point that appeared to be caused by the discharge, in violation of Receiving Water Limitation No. G.5. 2. Waste Discharge Requirements Order No. R5-2002-0088 Standard Provision General Provisions No. A.6 states: "The Discharger shall at all times properly operate and maintain all facilities, and systems of treatment and control including sludge use and disposal facilities (and related appurtenances) that are installed or used to achieve compliance with this Order. Proper operation and maintenance includes adequate laboratory controls and appropriate quality assurance procedures. This provision requires the operation of backup or auxiliary facilities or similar systems that are installed by the Discharger only when necessary to achieve compliance with this Order." Algae growth in the secondary clarifiers is an indication that the facility may be having operational problems. 3. The WWTP is effectively nitrifying ammonia to nitrate as evidenced by the laboratory analyses, which did not detect ammonia or nitrite in the effluent sample. However, the WWTP appears to have difficulty denitrifying nitrate to nitrogen, as shown in the laboratory analysis, which detected nitrate in the effluent sample at a concentration above the monthly average limitation. Donner Summit violated the nitrate monthly average effluent limitation for June 2008. On 2 July 2008, ECO:LOGIC Engineering, Inc., consultant for Donner Summit PUD, surveyed biostimulation in the South Yuba River at and about the effluent discharge point. ECO:LOGIC submitted their findings to the Regional Water Board in a report dated 11 July 2008. ECO:LOGIC found a correlation between the locations of algae and the effluent discharge point among other conclusions: "Based on the field observations, it is a reasonable conclusion that the DSPUD effluent discharge was at least a major contributing factor to a reportedly rare, highly unusual, transient growth of filamentous green algae in the South Yuba River in June 2008 in the reach from the DSPUD effluent discharge point, downstream through the Towle Mountain Estates area, but not as far downstream as Kingvale. The filamentous biofilm tracks fairly well to the effluent discharge point," (page 5). By 8 September 2008, please provide a technical report to address the following issues: 1. The inability of the WWTP to denitrify and to remove nitrate from the discharge. The WWTP cannot consistently meet its effluent limitation for nitrate, as evidenced by historical nitrate effluent concentrations. Please provide plans and a time schedule for reducing nitrate concentrations in effluent to comply with effluent limitations and to prevent further violations of receiving water limitations. 2. The condition of the clarifiers, and the concerns raised about filter operations support that the WWTP is encountering operational problems. Please provide a detailed explanation of the problems, and the measures being taken to improve operations at the facility. Regional Water Board staff will evaluate whether additional enforcement for the problems described above is appropriate upon review of the technical report. The full report is available for download here as a .pdf file. © Copyright YubaNet.com |
