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<DIV>
<DIV>Josh, </DIV>
<DIV> You have come to the right person to enhance your
work with reducing pesticide residues in drinking water. I do belive in divine
intervention. </DIV>
<DIV> Just so happens that I was highly involved
politically in the early ( 1985?) local work to reduce wellfield groundwater
contamination of primarily organic hydrocarbon solvents from
landfills. I also have close ties to Ohio State here where most of the research
work with reducing pesticide residues in groundwater took place. This is because
I was a licenced pesticide applicator for nearly 30 years. I also have followed
groundwater issues through my hobbie as a caver. </DIV>
<DIV> A few useful facts: </DIV>
<DIV> 1) Dayton, Ohio, was the first place in the world to
have a Groundwater Protection Ordinance. Work by local environmental companies,
Colleges and the EPA, along with some funding from the Air Force
produced the first air strippers still in use today. They
work to evaporate VOC's ( Volitile Organic Compounds) from
groundwater contamination interceptor wells. Inside the air stripper
towers, contaminalted groundwater is cascaded over a rising airstream. The water
is then returned to a river to complete the task of removing remaininig
traces of VOC's. The wellfields my children drink from are protected
from leaching solvents near the source of contamination. </DIV>
<DIV> 2) A great deal of work was funded by pesticide
producers at OSU ( Ohio State University) and possibly ODARC in the 1990's to
investigate cases of farm well contamination. The results were quite
encouraging. Extensive studies showed that only the concentrated pesticides
being dumped near the wells when over filling spray tanks was causing the
vast majority of contaminated drinking water cases. </DIV>
<DIV> Normal proper use of pesticides in the field
following lable recomendations resulted in no contamination of groundwater with
only a rare few minor exceptions. Note that this was done with early 1990's era
pesticides in use in the USA. More persistant DDT, Chloridane, and other
older, banned chemicals were not considered. I'm sure traces were detected
in the studies from old spills. </DIV>
<DIV> The new guidelines were written for:
filling tanks and spraying only away from wells, use of backflow and
shutoff devises, construction of spill containment pads, along with other
measures to reduce spills of concentrate, all have largely eliminated the
contamination problems. New wells, drilled away from contaminated areas
have now proven clean sources of drinking water over time. The biological
activity in the shallow depths of the fields degrades the pesticides completely
in most cases. Only excessive applications on porous soils with heavy rain
following the application produced measurable trace leaching below the surface.
</DIV>
<DIV> The newest chemicals have been designed and put to
these tests with even more monitoring of field residues. New application
techniques take field studies into consideration. IPM or Intigrated Pest
Management, now reduces the use of pesticides to only as needed. </DIV>
<DIV> </DIV>
<DIV> My recomendations: </DIV>
<DIV> A) I would consider an airation step early in your
water treatment program. This would reduce the VOC's and allow for longer use of
Charcoal. Also use of lime to precipitate acidic formulations before filtering
would help. </DIV>
<DIV> B) I would examine pesticide use management
programs in areas where residues are being found. You might even ask
representatives from the companies producing and selling the pesticides to
examine the application procedures. Nobody knows their chemicals better than
them. Any contamination from their chemicals is bad for their sales. </DIV>
<DIV> C) Following up along with new wells drilled where
contamination is untolerable will make water purification much easier. Reverse
osmosis for severly contaminated drinking water may be an expensive but
necessesary option in the short run. </DIV>
<DIV> D) The greatest risk from traces of most of these
chemicals mentioned is internal cancers and brith defects. Neither of which is
easy to quickly trace back to the source of the problem. You might want to
monitor the nearby clinics for spikes in these problems. Encourage
expectant and nursing mothers to watch the source of drinking water. </DIV>
<DIV> Glad that all this dormant knowledge can again be
put to use. Good luck.</DIV>
<DIV> </DIV>
<DIV> Dan Dimiduk </DIV>
<DIV> Founder : Shangri- La Research and Development.
</DIV>
<DIV> Owner: Carefree Landscape Maintenance Co. </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>In a message dated 6/16/2013 8:50:14 PM Eastern Daylight Time,
yeah.yeah.right.on@gmail.com writes:</DIV>
<BLOCKQUOTE
style="BORDER-LEFT: blue 2px solid; PADDING-LEFT: 5px; MARGIN-LEFT: 5px"><FONT
style="BACKGROUND-COLOR: transparent" color=#000000 size=2 face=Arial>High
draft/high temp. chars are superior from a sorption perspective: <A
title=http://www.wcponline.com/pdf/October2012Kearns.pdf
href="http://www.wcponline.com/pdf/October2012Kearns.pdf">http://www.wcponline.com/pdf/October2012Kearns.pdf</A>
<DIV><BR></DIV>
<DIV>The lower mass yields are more than offset by greater-than-proportional
increase in sorption capacity. For water treatment/water quality applications
85-90%, or even a little more, mass loss is optimal.</DIV>
<DIV><BR></DIV>
<DIV>We'll have several papers coming out over the next couple of years
filling in a lot of the details on research into a lot of the questions that
have been brought up by Dan and others here....sorry, everyone, academic
publishing is so painfully slow.....</DIV>
<DIV><BR></DIV>
<DIV>Josh</DIV></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV> </DIV></FONT></BODY></HTML>