Biofuels, Alternate energy

Impacts of fracking in USA

Posted by Susan Sharma on December 13, 2016

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Here is a report published on 13 December, 2016
U.S. EPA Releases Final Report on Impacts from Hydraulic Fracturing Activities on Drinking Water Resources 
EPA’s report concludes that hydraulic fracturing activities can impact drinking water resources under some circumstances and identifies factors that influence these impacts

WASHINGTON - The U.S. Environmental Protection Agency (EPA) is releasing its scientific report on the impacts from hydraulic fracturing activities on drinking water resources, which provides states and others the scientific foundation to better protect drinking water resources in areas where hydraulic fracturing is occurring or being considered. The report, done at the request of Congress, provides scientific evidence that hydraulic fracturing activities can impact drinking water resources in the United States under some circumstances. As part of the report, EPA identified conditions under which impacts from hydraulic fracturing activities can be more frequent or severe. The report also identifies uncertainties and data gaps. These uncertainties and data gaps limited EPA’s ability to fully assess impacts to drinking water resources both locally and nationally. These final conclusions are based upon review of over 1,200 cited scientific sources; feedback from an independent peer review conducted by EPA’s Science Advisory Board; input from engaged stakeholders; and new research conducted as part of the study. 


"The value of high quality science has never been more important in helping to guide decisions around our nation’s fragile water resources. EPA's assessment provides the scientific foundation for local decision makers, industry, and communities that are looking to protect public health and drinking water resources and make more informed decisions about hydraulic fracturing activities,” said Dr. Thomas A. Burke, EPA's Science Advisor and Deputy Assistant Administrator of EPA's Office of Research and Development. "This assessment is the most complete compilation to date of national scientific data on the relationship of drinking water resources and hydraulic fracturing."

The report is organized around activities in the hydraulic fracturing water cycle and their potential to impact drinking water resources. The stages include: (1) acquiring water to be used for hydraulic fracturing (Water Acquisition), (2) mixing the water with chemical additives to make hydraulic fracturing fluids (Chemical Mixing), (3) injecting hydraulic fracturing fluids into the production well to create and grow fractures in the targeted production zone (Well Injection), (4) collecting the wastewater that returns through the well after injection (Produced Water Handling), and (5) managing the wastewater through disposal or reuse methods (Wastewater Disposal and Reuse). 

EPA identified cases of impacts on drinking water at each stage in the hydraulic fracturing water cycle. Impacts cited in the report generally occurred near hydraulically fractured oil and gas production wells and ranged in severity, from temporary changes in water quality, to contamination that made private drinking water wells unusable.

As part of the report, EPA identified certain conditions under which impacts from hydraulic fracturing activities can be more frequent or severe, including:

  • Water withdrawals for hydraulic fracturing in times or areas of low water availability, particularly in areas with limited or declining groundwater resources;
  • Spills during the management of hydraulic fracturing fluids and chemicals or produced water that result in large volumes or high concentrations of chemicals reaching groundwater resources;
  • Injection of hydraulic fracturing fluids into wells with inadequate mechanical integrity, allowing gases or liquids to move to groundwater resources;
  • Injection of hydraulic fracturing fluids directly into groundwater resources;
  • Discharge of inadequately treated hydraulic fracturing wastewater to surface water resources; and
  • Disposal or storage of hydraulic fracturing wastewater in unlined pits, resulting in contamination of groundwater resources.

The report provides valuable information about potential vulnerabilities to drinking water resources, but was not designed to be a list of documented impacts.

Data gaps and uncertainties limited EPA’s ability to fully assess the potential impacts on drinking water resources both locally and nationally. Generally, comprehensive information on the location of activities in the hydraulic fracturing water cycle is lacking, either because it is not collected, not publicly available, or prohibitively difficult to aggregate. In places where we know activities in the hydraulic fracturing water cycle have occurred, data that could be used to characterize hydraulic fracturing-related chemicals in the environment before, during, and after hydraulic fracturing were scarce. Because of these data gaps and uncertainties, as well as others described in the assessment, it was not possible to fully characterize the severity of impacts, nor was it possible to calculate or estimate the national frequency of impacts on drinking water resources from activities in the hydraulic fracturing water cycle. 

EPA's final assessment benefited from extensive stakeholder engagement with states, tribes, industry, non-governmental organizations, the scientific community, and the public. This broad engagement helped to ensure that the final assessment report reflects current practices in hydraulic fracturing and uses all data and information available to the agency. This report advances the science. The understanding of the potential impacts from hydraulic fracturing on drinking water resources will continue to improve over time as new information becomes available. 

For a copy of the study, visit www.epa.gov/hfstudy.

Biofuels, Alternate energy

Preparation of Biomass Briquettes for Gasification

Posted by Jishu Kinkar Medhi on July 22, 2013

Blog

Steps for briquette formation

·        Collectionof biomass in required quantity

·        Eliminationof any unwanted stuffs from the biomass and subsequently making it free fromany dirt and soil

·        Grindingthe biomass into fine particles

·        Passingthe biomass through sieve to eliminate large chunks of biomass that might bepresent in it

·        Preparationof slurry by mixing the biomass with binder and water

·        Mouldingof briquettes in small size from the prepared slurry

·        Dryingof briquettes


Procedure

The first step for briquetteformation is the preparation of slurry. Slurry is the mixture of biomass withbinder and water. For making the slurry, a fixed quantity of binder is firstmixed with water and made into a sticky paste. The amount of water added shouldjust be enough to make it a paste. After that, the biomass particles must beadded to it in required quantity following which the ingredients are thoroughlymixed to make the slurry.

The slurry thus formed must now bemoulded into briquettes while it is still soft. Moulding of briquettes may bedone in two ways – either by hand or by machine. In our case, briquettes weremoulded by hand only.

The briquettes thus prepared are verysoft and wet at the beginning and capable of deformation due to the highmoisture content. Therefore they are required to be kept in the open or underthe sun to dry. Generally they are kept for about 2 weeks in the sun to dry offand become hard and solid. While drying, it is important to take care that thebriquettes are not subjected to any kind of interference or otherwise be tamperedwith which might spoil the briquettes.




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