Summary of Filter Research
Pervious concrete as a filter material was tested with two goals in mind: low cost metals recovery from acid mine drainage remediation and hygienic water supply. The following comprises a brief summary of the results of this research, with a more complete description in the Details section of this site. Acid Mine Drainage	Pervious Concrete Filter Research Summary Suitable for remediation of Acid Mine Drainage Significant reduction in water borne microorganisms Manufacturing process, per unit cost and lifespan suitable for developing countries

Acid mine drainage (AMD) is a problem worldwide. In the US alone, the Department of Environmental Protection estimates "the annual cost to state taxpayers for AMD remediation to be $23 million dollars a year and the estimated state wide value of sludge from these systems to contain millions of dollars in metals, yet it is handled as waste."

Research Objectives:

• Acid Mine Drainage (AMD) contributes to surface water pollution.
• Global demand from large developing countries has increased mining activities as well as the use of alternative sources such as scrap metal.
• AMD waters may be another potential source of metals.

Research Results:

• The average percent concentration of iron in the filtrate was 15% of the original concentration.
• The average percent concentration of sodium in the filtrate was 39% of the original concentration.
• The average percent concentration of zinc in the filtrate was 26% of the original concentration.
• The average percent concentration of sulfate in the filtrate was 37% of the original concentration.
• Hydraulic breakthrough appears to occur around the 5th sample hour.
• This coincides with the observation of the entire filter being saturated with influent.

Hygienic Water

The World Health Organization estimates that 80% of all sickness in the world can be contributed to non-potable water and sanitation [Washington Post, 1997].

If no action is taken to provide suitable means of obtaining clean drinking water, as many as 135 million people will die from water-related diseases by 2020 [Pacific Institute, 2002].

Research Objectives:

• The 2007 EPA P3 competition committee desired to create a filter that could remove both microorganisms and non-living contaminants from water.
• The filter would use a material or materials that did not create a significant burden on the financial and infrastructural conditions of developing communities.
• Pervious concrete was selected as the material to evaluate.

Research Results:

• This analysis examines the ability of the filter to remove and/or neutralize Micrococcus luteus bacteria.
• This bacteria is on average the same diameter as E. coli but circular instead of tube shaped (and thus smaller overall) as well as less harmful.
• The filter experienced only 3 successful penetrations of 1-2 colony forming units (CFUs) however in those instances still achieved greater than 1 E+09 percent removal.
• pH measurements taken at during this test show an increase of pH by a factor of 5 when pH 7 water was used with a filter having a X x X sq. inch cross section . When pH 2.7 water was used with 2 filters having a Y x Y sq. inch cross section, the pH was raised by a factor of 3.5.
• The X x X sq. inch filter increase the DO concentration in the test water by an average of 1.82 mg/L in bacterial filtration samples and by 1.76 mg/L in the metals filtration tests.
• The X x X sq. inch filter decreased the temperature of the test water by an average of 1.18 degrees Celcius. The temperature was not measured during the taking of bacterial samples to ensure the samples were quickly placed into refrigeration.
• The Y x Y sq. inch filter's filtrate was not tested for DO.
• The Y x Y sq. inch filter did not measurably change the temperature of AMD water.
• The Y x Y sq. inch filter was also tested for the removal of filtrates as part of AMD remediation analysis. The average percent removal was 63%.

Sustainability

• The per unit cost and lifespan of the filter may be attractive for developing countries for both AMD and improved drinking water quality applications.
• Any country with existing ready mixed concrete infrastructure can produce the filter.
• Filters may have a long storage life and can be easily transported for use in remote areas and disaster relief.
• The filter is not designed to be load bearing.
• Recycled concrete to be used as a source of aggregate, requiring the fines to be removed by sieve.
• The filter can be easily produced by manual or automated processes.