09/21/1995 BOARD OF HEALTH Minutes

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i ANALYTICAL SYSTEMS INC. OPERATIONAL ANALYSIS SYSTEM DESIGN P.O. BOX 720 SANDWICH, MASSACHUSETTS 02563 (508) 833.8856 July 28, 1995 To Whom It May Concern From: Analytical Systems, Inc. Subject: Upgrade of Stafford Ponds Septic WWT System into a Cromaglass Modular SBR Wastewater Treatment Facility During the pas+ two months, ASI has been exploring with Carl Grassetti, developer of Stafford Ponds, various Cromaglass alternative configuration options which lend themselves to the modular upgrade of the current septic system into a full on-site wastewater treatment plant. After investigating several options, ASI recommends the follow Option A as the most cost effective and environmental prudent for all concerned. This option provides both the Town of Mashpcc and the properly owners of Stafford Ponds with a modular state-of-the-art plant whose evolving treatment capability is always better than the previous growth increment. The basic concept of this option is based upon three situations where Cromaglass has replaced similar septic tank systems within the past six years. In the Central Columbia Schools of Bloomsburg Pennsylvania situation, for example, 1/4 of the 16,000 GPD average today is coming directly from an elementary school septic system. With this proven capability to handle partially treated effluent flows of septic systems, it is anticipated the Stafford Ponds septic flows would gradually be diverted until the whole septic flow is absorbed when this project about 2/3rd of its projected built-out. In this manner, the Cromaglass SBR 20/20/7.5 performance capability can comfortably maintained within the DEP required 30/30/10 levels of treatment. ASI's prcliminary recommendation would be to divert 1/3 of the current septic effluent flows when the 2nd SBR unit is added,2/3rd when the 3rd unit is added and all of the septic tank flows when the 4th SBR unit is brought on- line. Following this incremental "drawdown approach", it is possible to gradually lower the current level of septic pollutants to less than 1/2 of their current valves by the time the project passes through the 2/3rd (-234 bedrooms)build-out phase. Figure 1 provides an overview of how Nt(nitrogen) entering the ground water will be reduced as the total number of project bedrooms increase.This "drawdown profile" is based on two simple assumptions. They are 1) CA-120 SBR modules will be added at a rate of one for each 34 new bedrooms constructed and 2) the current septic flows will be incrementally diverted in steps of 1/3rd,2/3rd and 100% as the 2nd,3rd &41h CA-120 SBR units are brought on-line. The resulting sawtooth effect results when an additional CA-120 unit is brought on- line and wastewater flows are essentially the same as when the treatment plant operated with one less SBR unit_ First and foremost,it clearly indicates the environmental benefits