4/18/1996 BOARD OF HEALTH Minutes

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MINUTES April 18, 1996 BOARD OF HEALTH 10, major impacts, trying to contain it on Ashumet Pond, very difficult." 61t9s going to take a lot more study but there is one critical area just north ofSandwich Road which has extremely high concentration of one of the chlorinated solvents." "We are going to do a demonstration, a pilot test project." "we've heard about recirculating wells." "It actually treats the water in place, you don't have to remove it so you don't have anydraw-down impacts on the ponds." `we're going to install a well such as that in that high concentration area to try and reduce the mass ofcontaminants in that area as a demonstration to see if the technology works because there is some concern based on the depth, etc. as to whether it would be effective or not." `ewe think it is a good place to try it because we can see, at that point m time, a very significant change in the water chemistry if it does wort ." `ewe don't take the water out we volatile out ofthe water the constituents, the solvents and then we tale that air extracted and run it through a carbon treatment vessel above ground."' Mr. Baker questioned, "Has that water been tested to see that it's not high in iron?" n` " 1 lr, Mnuor responded, "'What's part of the evaluation." "There is still technically, a separation between Ashumet Valley plume and where we know the CS 10 one is now." "We don't know w that it is interconnected but it is a eornplieatrng factor because if they did overlap the Ashumet Valley plume would be much shallower- than the CS 10 plum which reales it difficult, from any treatment stand point, but not something that cant be looped at." "With the recirculating well that we are going to try, if that works extremely well and resolves the issues of getting the water cleaner then we're going to try that over a much larger area so we can then use that type of well to contain the plume without actually pumpingout those massive quantities of water every way." "Jn that moray, there will be no unp act on the pond."' "Our future goal is to hope that it will work that way." Mr. McQuaid stated, "we know v that both of these plumes are at the ponds edge if not beyond."' "Are there laps t install monitoring wells south of these ponds where they y p predict the plumes may, if there going to, underflow the pond?,"" W. M n it responded, "Yes." Mr. McQuaid commented, "Secondly, as you know, over the past several years we've one out and tested the ponds ourselves, both at the bathing beaches and deep g spots."' "I know that John's and Ashumet Pond's task force recommended that be discontinued or done quarterly." "we intend to do it monthly in the summer tune.