April 2013, Vol. 25, No.4

Research Notes

U.S. EPA releases progress report on hydraulic fracturing study

The U.S. Environmental Protection Agency (EPA) is tackling the challenge to better understand the effects of hydraulic fracturing on drinking water resources. The agency recently released an update of its ongoing research titled Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: Progress Report.  

In 2011, EPA began research under the Plan to Study the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources. According to the progress report’s executive summary, this research centers around five stages of the hydraulic fracturing water cycle and a research question on each stage’s effect on drinking water resources, including 

 

  • water acquisition and possible effects from large-volume water withdrawals from groundwater and surface waters;  
  • chemical mixing and possible effects of hydraulic-fracturing-fluid surface spills on or near well pads;  
  • well injection and the possible effects of the injection and fracturing process;  
  • flowback and produced water, and the possible effects of surface spills of hydraulic fracturing wastewater on or near well pads; and  
  • wastewater treatment and waste disposal, and the possible effects of inadequate treatment of hydraulic fracturing wastewater. 
  • The report outlines work being conducted and provides updates on 18 research projects that will inform the final study. The projects are organized according to five different types of research activities: analysis of existing data, scenario evaluations, laboratory studies, toxicity assessments, and case studies.   

So far, data have been obtained from nine hydraulic fracturing service companies, 333 well files supplied by nine oil and gas operators, more than 12,000 chemical disclosure records from FracFocus, and spill reports from four different sources, the report says. 

Results of the study are expected to be released in a draft for public and peer review in 2014, the news release says. For more information, see www.epa.gov/hfstudy  


 

 

Finnish researchers find way to reduce phosphorus in pulp-mill wastewater

Aalto University (Espoo, Finland) researchers have devised a method to reduce phosphorus content in pulp-mill wastewater and solids. In the method, precipitation using iron sulfate occurs simultaneously with biological wastewater treatment, eliminating the need for a separate treatment stage, according to a university news release.  

Researchers add iron sulfate prior to the biological treatment, and phosphorus dissolved into the water precipitates with the biomass at the treatment plant. Phosphorus is removed from the system along with solids. Because pulp-mill solids generally are burned, this phosphorus becomes ash and can be reused as fertilizer, the news release says. 

During tests, the method reduced phosphorus by more than 80% when 10 mg/L of iron was fed into the process, says researcher Sakari Toivakainen in the news release. 

The process does not require additional wastewater treatment units, so there is no need for additional energy. Also, iron sulfate is inexpensive, and the solids are easier to process than those produced by post-treatment precipitation, which uses aluminum, the news release says. 

The method, designed to save operational and energy costs, was developed and pilot-tested in laboratories at the university’s Otaniemi campus, the news release says. Research on the method has been published in the journal Water Science & Technology. 


 

 

February WER identifies areas in a Boston watershed susceptible to stormwater pollution

After examining pollution loads in Boston’s Wachusett Reservoir watershed, University of Massachusetts (Amherst) researchers prioritized subbasins and identified areas susceptible to stormwater pollution. 

The research, reported in the February issue of Water Environment Research (WER), uses the Catchment Prioritization Index (CPI) to identify clustered hotspots through application of the Getis–Ord Gi statistic. 

The reservoir is a primary drinking water resource for the Boston area, with a drainage area of 280 km2. The area has been urbanized by increased residential, commercial, industrial, and transportation land use, as well as increased impervious surface area, runoff, and pollutant loads to the reservoir, the report says. 

The study assessed the effects of land-use change on stormwater and water quality. The objectives were to estimate stormwater pollutant loads from the watershed that affect water quality and prioritize areas of concern and their changes throughout 3 decades, the report says. 

Researchers observed hotspots of higher levels of fecal coliform bacteria loading. The approach used can prioritize subbasins for future stormwater monitoring strategies and best management practices, the report says. The approach also is applicable to other regions. 

“This research confirmed that urbanization of a watershed greatly affected stormwater runoff, and that highlighted urbanized [subbasins] contributed to the largest stormwater pollutant loads,” the report says. The research concludes that a sequential approach with a geographic information system consisting of the stormwater mass load estimation, CPI calculation, and hotspot analysis is an effective way to prioritize areas for best management practices. 

The article, “Prioritizing Subwatersheds for Stormwater Pollution to Wachusett Reservoir,” is available as an open-access document and can be downloaded free at http://goo.gl/yf8vP .  

 

Water Environment Research allows open access to one article per issue on a range of important technical topics such as nutrient removal, stormwater, and biosolids recycling.