Laserfiche WebLink
Page 1 of 2 <br /> Tom F. Fudala <br /> From: tomfudala@comcast.net <br /> Sent: Sunday, December 12, 2010 8:24 PM <br /> To: AAREDEYE@aol.com <br /> Cc: Tom F. Fudala <br /> Subject: Re: Quandry <br /> Joe: <br /> Just a few info items regarding some of your numbers. Because of biological activity in <br /> the leaching area of septic systems, while septic effluent leaves the tank at 35-40 mg/I <br /> nitrogen, it's down to 26.5 mg/I or so by the time it gets to groundwater according to <br /> MEP. On-site denitrifying (I/E) septic systems average 19 mg/I before the leaching <br /> area, based on the records kept Cape-wide by the County Health & Environment <br /> Department. Existing private wastewater treatment plants in Mashpee typically <br /> discharge at 3-9 mg/I, depending on the technology and whether or not they're working <br /> properly (they all have a DEP permit limit of 10, so design for half of that to avoid permit <br /> violations). The Nitrex cluster at Main Steet Village near Town Hall averages about 3.5 <br /> mg/I so far (the project is not fully built). Any plants we build or upgrade would be <br /> designed to average 2-3 mg/I in plant effluent, which is close to the lowest you can get <br /> with biological processes. Any lower numbers would involve membrane filtration, which <br /> might get numbers in the 1-2 range. <br /> When you get that low, there's little nitrogen left to get taken up in soil, Le. through <br /> spraying in woods or on a golf course. However, DEP does not look too favorably on <br /> spray irrigation of wastewater effluent due to concerns about viruses, which seem to be <br /> able to survive even the best treatment processes. Falmouth has/had a spray irrigarion <br /> area in a wooded area at their treatment facility, but DEP required that it be fenced to <br /> keep humans away from potential virus-borne diseases. That's why we've focused on <br /> subsurface discharge either in the root zone of golf course / ballfield grass theough <br /> small diameter emitter systems, or beneath the root zone through the same kind of <br /> emitters or through leaching galleries. <br /> Sand filter beds are by far the most efficient and easily maintained means to dispose of <br /> treated effluent (twice as much discharge per acre as subsurface means). The other <br /> ideas that have been mentioned (see Technology Screening report) are deep injection <br /> wells and shallow injection pits, neither of which have been permitted yet by DEP, <br /> though they would take up a lot less acreage. <br /> Ocean outfalls are prohibited by the State' Ocean Sanctuaries Act, which is not likely to <br /> be changed soon just to benefit us, although Falmouth has taled about seeking <br /> approval in Woods Hole and the idea may make some sense (it certainly seems <br /> simpler). <br /> Hope to see you at tomorrow's meeting (Monday 7pm) as we try to finalize a draft <br /> scheme or 2 to send off to the collection system vendors. <br /> Also hope you got a chance to look at what the Budget Subcommittee came up with for <br /> a May Town Meeting proposal (we missed you at the meeting), as well as the proposed <br /> web site pages, which are scheduled to go live Tuesday if we approve them tomorrow. <br /> 12/13/2010 <br />