[Stoves] Low temperature vs high temperature charcoal?

[Carefreeland at aol.com]

Josh, 
    You have come to the right person to enhance your  work with reducing 
pesticide residues in drinking water. I do belive in divine  intervention. 
    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. 
    A few useful facts: 
   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. 
    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. 
    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. 
    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. 
    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. 
    
    My recomendations: 
    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. 
    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. 
    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. 
    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. 
    Glad that all this dormant knowledge can again be  put to use. Good 
luck.
    
    Dan Dimiduk 
    Founder : Shangri- La Research and Development. 
    Owner: Carefree Landscape Maintenance Co. 
 
 
In a message dated 6/16/2013 8:50:14 PM Eastern Daylight Time,  
yeah.yeah.right.on at gmail.com writes:

High  draft/high temp. chars are superior from a sorption perspective: 
http://www.wcponline.com/pdf/October2012Kearns.pdf   


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.


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.....


Josh



 
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