Resolution No. 4793 - Laserfiche WebLink

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~WMC FACILITIES PLAN · Increased risk associated with potential groundwater contamLnation if lagoon liner failed - Conversion to FSL could require complete relining of lagoon As mentioned above, the conversion of the S1WF lagoon into a fifth FSL would provide the FSL capacity needed by 2015. This assumes that future modifications and additions to the digestion process at the WPCF do not decrease the VSS loads to the existing FSLs. The FSL conversion would require cleaning out the SIWF lagoon and repairing the liner ~f an inspection showed signs of leakage. An equipment inventory and condition assessment would also be required. For comparison purposes, the estimated cost to construct a new FSL is approximately $2 million. This assumes that 10 acres of new land (agriculturally zoned) can be purchased for approximately $50,000/acre. This does not include additional mechanical costs (piping and pumping) to connect the FSL to the existing FSLs. Under this alternative the following modifications would be required: A tee and an 8-inch pipeline off of the existing 8-inch biosolids force main that conveys digested sludge from the WPCF to the BMF. This extension would serve the dual purpose of conveying liqtud biosolids to the SIWF and back from the StWF to the nuxmg tanks, if required. It is assumed that the existing digested sludge pumping capacity at the WPCF would be sufficient to convey digested sludge to the SIWF lagoon. A pump station would be required to pump liquid biosolids from the SIWF lagoon to the mixing tanks at the BMF. A 10-inch pipeline and pump station to convey supernatant overflow from the SIWF lagoon to the existing collection system. · An optional pipeline and pump station to convey filtrate from the BFPs at the BMF to the SIWF lagoon. Further analysis of this option would be recommended if this alternative were selected. For cost purposes, a filtrate flow of 500 gpm and pipeIine diameter of 6 inches were assumed. In this alternative, MWMC could either continue to lease the SIWF for farming activity, or develop the site to apply liquid biosolids and/or supernatant and effluent. If s-upernatant and/or effluent were applied on the SIWF land, the exist~mg center pivots would require retrofitting the sprinklers on the center pivot to allow for irrigation of this material. The site may require a pump station and hose reel system or other irrigation system if liquid biosolids were to be applied. Biosolids could alternatively be land applied by truck. This alternative would provide a source of supernatant and liquid biosolids at the SIWF for effluent and biosolids reuse on the 215 acres, as well as a convenient "lower-cost" location for future biosolids overflow/storage. This alternative appears to be attractive with regards to MWMC's long-term biosolids and effluent reuse program. Alternative 4 - Use the SIWF for Biosolids and Effluent Reuse Alternative 4 represents using the SIWF for biosolids and effluent reuse only. It is assumed that biosolJds and/or effluent reuse would be applied on grass crops at the SI~/F and that 6.-48 UWMC_6,O_REV11,00C