Showing posts with label Potential. Show all posts
Showing posts with label Potential. Show all posts

Sunday, July 10, 2011

Investigation Reveals Potential Public Health Hazard - WVNS-TV

CHARLESTON -- Scientists call it "leachate." Trash haulers call it "compacter juice." It's the awful stuff that trickles, oozes and splashes out the back of the trucks that haul your garbage.

No question it's dirty. But our news department wondered if it was also dangerous.



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(The video above is not related to the article but we thought it might interest you.)

So we had it tested. What we found shocked the seasoned experts we consulted. And it may mean the street where you live has a lot more in common with an open sewer in a Third World country than you ever imagined.

We followed compactor trucks on three separate days in different parts of Charleston, watching them crush trash and squeeze out smelly trails and pools of liquid on dozens of streets. It quickly became clear the cloudy fluid was pouring out into puddles or being drizzled in looping arcs up one street and down another.

But is it dangerous?

We took samples from a random truck on a random day. Not a scientific study, but a kind of snapshot of the contamination draining onto the streets from city garbage trucks.

"When I first saw the results for the fecal coliform, for the E. coli, I was pretty shocked at the large amount of bacteria found in the leachate," said Anita Ray, Environmental Health Director at the Kanawha-Charleston Health Department. "I am not used to seeing counts that high in things that we would routinely sample, such as outflow from a malfunctioning sewage system."

That's right. Contamination levels in the liquid are so high the only thing to compare it to is untreated sewage.

"Quite obviously," said Ray, "from the lab results that you have pulled just from this one snapshot in time, it indicates there is a pretty high potential for a public health hazard."

The bacteria E. Coli can make you extremely sick, or even kill you. It's also used as an indicator of other dangerous microorganisms. It's so dangerous, levels of E. coli in treated wastewater, for instance, can't be more than a few hundred when it's poured into the Kanawha River (depending on the number of tests). But one leachate sample we took spewing from the back of a garbage truck came back with a reading well over 4,000,000. Another was 16,000,000. And a third pegged the meter. All the lab could determine was that it was above 60,000,000.

That's why Ray calls these puddles and wet trails on your streets a potential public health hazard. Even after it dries, it's picked up on shoes, stroller wheels, anything.

"The worst case scenario, as I've said before," Ray said, "is if you have a child that has a ball or something and runs through the street, the object runs through this stuff and then the child contacts it with their hands, then puts their hand in their mouth or whatever, you've got a real potential for a transfer of that E. coli into the child's system."

How does Ray account for readings that high?

"If I might speculate, which I don't like to do ordinarily," Ray offered, "it could also be because the trucks -- and I have no idea of knowing this -- may not be cleaned out on a daily basis, and that may be showing up as a accumulative residue, if you will, of that bacteria along with the day's collection."

In other words, an unwashed truck could wind up being a big Petri dish, collecting and growing bacteria over time, and then spewing it out onto your street for your kids to play in and your dog to track into the house. And maybe make you very sick.

You can find a copy of our lab results here.

In the second part of this Hometown Investigation, we'll look under Charleston garbage trucks to figure out why so many leave wet trails of dangerous leachate behind, and we'll reveal the $10 fix for the problem.


View the original article here

Sunday, December 05, 2010

A Survey of the Current and Potential Analytical Techniques for the Speciation of Radionuclides in Nuclear Waste Repository Groundwaters and Simulation Leachates

Sanitary landfills are the most widely utilized method of solid waste disposal around the world. With increased use and public awareness of this method of disposal, there is much concern with respect to the pollution potential of the landfill leachate. Depending on the composition and extent of decomposition of the refuse and hydrological factors, the leachate may become highly contaminated. As leachate migrates away from a landfill, it may cause serious pollution to the groundwater aquifer as well as adjacent surface waters. T


here is growing concern about surface and groundwater pollution from leachate. Better understanding and prediction of leachate generation, containment, and treatment are needed. This book contains a literature review of various methodologies that have been developed for prediction, generation, characterization, containment, control, and treatment of leachate from sanitary landfills. The contents of this book are divided into nine chapters. Each chapter contains theory and definition of the important design parameters, literature review, example calculations, and references. Chapter 1 is devoted to basic facts of solid waste problems current status and future trends towards waste reduction and recycling. C


hapter 2 provides a general overview of municipal solid waste generation, collection, transport, resource recovery and reuse, and disposal options. The current status of sanitary landfill design and operation, problems associated with the landfilling, and future trends are presented in Chapter 3. Methods of enhanced stabilization, recycling landfill space, methane recovery, and above grade landfilling, and closure and post closure care of completed landfills are also discussed in detail. Chapter 4 provides a general overview of Subtitle D regulations and its impact upon sanitary landfilling practices. Chapter 5 is devoted entirely to moisture routing and leachate generation mechanisms.


Examples of calculation procedure for determining the leachate quantity produced at a landfill are presented. Chapter 6 is devoted to chemical characterization of leachate that changes over the life of the fill. Both theoretical and experimental results are provided to estimate the leachate quality. Chapter 7 provides leachate attenuation processes and mechanisms. Chapter 8 is devoted to leachate collection systems. Natural soil sealants, admixed materials and synthetic membranes, their effectiveness, and methods of installation and economics are fully discussed.


Chapter 9 provides a detailed review of leachate treatment methodology. Kinetic coefficients and treatment plant design considerations are summarized for the sole purpose of assisting con- sultants to design leachate treatment facilities. Leachate treatment case histories and numerous process trains are presented for treating leachate from young landfill. The book also describes how the process train can be changed effectively as leachate quality changes with time.


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Friday, October 01, 2010

Potential for using constructed wetlands to treat landfill leachate: Literature review and pilot study design (Special report series)

This digital document is a journal article from Ecological Engineering, published by Elsevier in . The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
Four surface-flow mesocosm wetlands were operated at different hydraulic retention times during two periods to treat diluted woodwaste leachate that was acidic, of very high oxygen demand, and toxic. Temperature, dissolved oxygen, and redox potential decreased with increasing water depth. However, there was no significant vertical variation in microbial biomass. No significant development in biomass of planktonic microorganisms was found over 6 weeks of initial operation. It took <1-6 weeks for maturation of the biofilm on submerged plant surfaces and the sedimentary microbial community. Mass reduction efficiencies of chemical oxygen demand, and tannin and lignin increased significantly with hydraulic retention time when 10% leachate was fed with tap water. When a more recalcitrant influent was fed, there was a slight increase of reduction efficiency with increasing hydraulic retention time. Reduction rates increased linearly with mass loading rates up to 0.4kgm^-^3d^-^1 chemical oxygen demand and 0.13kgm^-^3d^-^1 tannin and lignin. Precipitation and evapotranspiration had profound impacts on the overall performance and its variability. Mass balance-based operating data of wetlands with a mature microbial community are required for proper performance assessment. formance assessment.

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