Agenda 02/08/2005 - Laserfiche WebLink

Home Browse Search

Martinsville Date: January 26, 2005 To: Dan Collins, City Manager From: John Dychcs, Director of Water Resources Subject: Inflow Reduction Program In years past, discharge permits primarily controlled what could be discharged from wastewater treatment plants. Over the years the permits have been expanded to also include control ofthe entire collection system, particularly in regard to CSO's (Combined Sewer Overflows) and SSO's (Sanitary Sewer Overflows). Many older Cities (Richmond, Lynchburg) had combined sewers that carried both storm and sanitary water, such that wet weather events would overwhelm the treatment plants. Fortunately, Martinsville has no "official" combined sewers, although there could be minor cross connections and probably some roof drains, stairwell drains and possibly isolated parking lot catch basins inappropriately connected to the sanitary mains. The City's collector system does, however, have considerable inflow during wet weather, probably mostly from manhole covers in streets, missing or broken cleanout caps, leaking manholes in low-lying areas, leaking or broken pipes near streams, plus some improper connections as noted above, such that during a hard rain flow at the treatment plant can increase from a normal $ MGD to over 16 MGD. Overflowing collector system manholes have not historically been a major problem, but if maximum flow at the plant is sustained for sufficient time, the sewage (diluted with storm water) must be bypassed to the river to avoid damaging treatment plant equipment. This has occurred about twice per year for the past ten years (list attached). The bypassed flow does receive minimal treatment through the primary clariflers and is chlorinated. Our current permit requires that these bypasses be reported to DEQ. Also, whenever a manhole in the collector system overflows to State waters, whether caused by storm water inflow or a blocked main, a report must be submitted. Reported bypasses/overflows are considered by the regulators to be violations of the Clean Water Act and have in the past caused some permit issuance problems, but in the future promise to play a much larger role. Forthcoming SSO regulations will require development ora CMOM (Capacity, Management, Operation and Maintenance) program in all localities to reduce these problems. 5$W¢.JCInJrchSIrccl I:O. Box 1112 M..1in,xille. VA 24114-1112 276-403-51XX)