Pervious Concrete Filter Details

Research Details

Two research programs have been completed investigating applications in Acid Mine Drainage and Hygienic Water supply.

The link below opens a detailed explanation of the findings in PDF format.

	Filtration of Polluted Waters by Pervious Concrete
Solubility of Metals in a High pH Environment

Filter Applications

I. Acid Mine Drainage Remediation

1. Acid Mine Drainage (AMD) contributes to surface water pollution.
2. Global demand from large developing countries has increased mining activities as well as the use of alternative sources such as scrap metal.
3. AMD waters may be another potential source of metals.
4. This is highlighted by a Pennsylvania Department of Environmental Protection study stating [Rathbun, 2004]:
5. "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." f
6. Experimental results have shown that:
   1. The filter increased the pH by an average factor of 3.3.
   2. The average percent concentration of iron in the filtrate was 15% of the original concentration.
   3. The average percent concentration of sodium in the filtrate was 39% of the original concentration.
   4. The average percent concentration of zinc in the filtrate was 26% of the original concentration.
   5. The average percent concentration of sulfate in the filtrate was 37% of the original concentration.
7. From a Sustainability perspective:
   1. The per unit cost and lifespan of the filter may be attractive for developing countries for both AMD and improved drinking water quality applications.
   2. Any country with existing ready mixed concrete infrastructure can produce the filter.
   3. Filters may have a long storage life and can be easily transported for use in remote areas and disaster relief.
   4. The filter is not designed to be load bearing.
   5. Recycled concrete to be used as a source of aggregate, requiring the fines to be removed by sieve.
   6. The filter can be easily produced by manual or automated processes.

II. Poverty Relief

1. local, low tech concrete plants or factories can make filters from separately pre-packaged ultra fine particles, gravel and Portland cement. Concrete companies at the regional or national level can prepare, package and sell these supplies at local prices.
2. Containers can be assembled on site from other local/regional suppliers or bought by the concrete companies, and given to subcontractors for final assembly before shipment, or all components can be collected and taken to the local area for final, on-site assembly.
3. Concrete materials are available almost everywhere, and ultra fine material should be easy to process and fairly readily available.
4. "Expired" cartridges can be swapped out by trained local people and sent back to the local concrete factory for recycling. The same local people can be trained to test the water using simple testing kits to determine when the cartridge is no longer effective.

II. Military applications

1. Field hospitals can assemble these filters and swap out "expired" cartridges as needed. They will also be able to test the water as needed for specific needs and add additional treatment as needed.
2. All of these filters can be recycled by military construction units or contractors using prepared ultra fine particles, portland cement and pebbles.

III. Underserved Communities

1. Communities in underserved areas of developed countries can utilize these filters in the same manner as impoverished communities, so those who do not choose or are unable to live in areas with formal water treatment plants can use the pervious concrete water filter to process surface and subsurface water for consumption.
2. These pervious concrete filters are also recycled by sending them back to concrete plants.
3. The filters can be sold as individual units for individual households or as larger units for small, multi-family communities.

IV. Other commercial applications

1. Water treatment kits for outdoors enthusiasts, national guard or civil protection units and as emergency treatment kits for ranchers and farmers.
2. The final stage of gray water systems, to remove all impurities from gray water after the water has been used for irrigation and before it is consumed.
3. Pretreatment for industrial or laboratory use.
4. Treating brackish water in tailings ponds where oil sand or oil shale mining is taking place (not yet experimentally proven).
5. Pre-treatment of salt water. This filter will not desalinate water to the point of making the water consumable, but it could remove significant amounts of salt (and chemical pollutants) which could prolong the life of filtration membranes and potentially reduce the amount of energy needed to desalinate water.

V. Lunar exploration

1. http://www.neiu.edu/~jmhemzac/mooncomp.htm (soil composition)
2. Portland cement composition: calcium silicate cement made with a combination of calcium, silicon, aluminum, and iron.
3. Similar soil composition means concrete could be produced on the moon, which means concrete filters can be produced.
4. A gray water system mixing human waste with artificially produced water would utilize the concrete filter as the last step to filter water for reuse in irrigation and other non-potable uses..

VI. Martian exploration

1. Iron ore mining http://science.nasa.gov/newhome/headlines/msad03mar99_1.htm
2. Rock composition http://mars.jpl.nasa.gov/MPF/science/mineralogy.html
3. Portland cement composition: calcium silicate cement made with a combination of calcium, silicon, aluminum, and iron.
4. Similar soil composition means concrete could be produced on the Mars, which means concrete filters can be produced.
5. A gray water system mixing human waste with artificially produced water would utilize the concrete filter as the last step to filter water for reuse for irrigation and other non-potable uses.