CORRESPONDENCE_4/7/22 [REV] APPENDICES W/FIRE PERMIT

Home Browse Search

Forward Resource Recovery Facility WDR Technical Report HDR Engineering, Inc. 9 October 2021 of 598,700 cf (approximately 4.5 million gallons or 10.1 acre-ft). The required retention basin is designed storage capacity to contain the runoff from a 25-year, 24-hour storm event for the entire compost facility is 235,200 cf (approximately 1.76 milion gallons of 5.4 acre-ft). The following table is based on a table included in the Compost Facility Stormwater Improvements Report to show the sediment basin storage capacity provided versus the required storage for a 25-year storm event. BASIN VOLUMES Provided Capacity Required Capacity – 25 YR 24 HR Storm Capacity with Freeboard 10.1 acre-ft 5.4 acre-ft Capacity without Freeboard 17.4 acre-ft 5.4 acre-ft This storage capacity is greater than the 25-year 24-hour storm required by the General Order for capturing run-off from all composting working surfaces. 3.2 Water and Wastewater Management Plan a) The potential process water from the composting working areas surface flows to on-site drainage ditches and is then directed to the on-site retention pond. Prior to reaching the pond, there are several best management practices implemented at the facility to reduce the potential for excess process water generation. First, facility operators are trained to use minimal water for dust control purposes. Second, when small quantities of process water are observed staff may spot clean these areas with wood chips to absorb the surface water run-off and reintroduce the material into the composting process. When larger amounts of process water are present this can be scooped up and applied to the compost pile in lieu of using water. Compost piles are not turned nor moved during rain events to further reduce the potential for excess process water generation. b) The facility has access to on-site wells to provide water for the operation, in some cases stormwater may be used as a substitute for dust control and process water. The compost cap on top of the ASP composting operation not only acts as a biofilter but also to minimize the potential for process water to escape the compost pile. c) Any process water generated from the operation in quantities that can be reused back into the process will be reintroduced into the compost process. In the event this water cannot be reused back into the compost process, it will be spot cleaned with woodchips or discharged to the on- site retention pond. The facility operators are trained to use minimal water for dust control to minimize the generation of surface water run-off from the composting system. d) Please see Appendix C for details on the stormwater retention pond and conveyance systems.