Saturday, November 25, 2006

Scrap tires to filter water? Science Blog: "Every year, the United State produces millions of scrap tires that clog landfills and become breeding areas for pests. Finding adequate uses for castoff tires is a continuing challenge and illegal dumping has become a serious problem throughout the nation. Dr. Yuefeng Xie, associate professor of environmental engineering at Penn State Harrisburg, has developed a method that uses crumb rubber to filter wastewater, which can help ease the tire problem and clean up the environment at the same time. 'My research has found that crumb rubber, derived from waste tires, can be used as a filter media,' Xie explains. 'The crumb rubber could be used for treating wastewater, ship ballast water, and storm water.' "Crumb rubber is produced by chopping up and grinding up waste tires to a desired size, cleaning the rubber and removing any metal particles. It is currently being used in highway pavement, athletic track surfaces, playgrounds, landfill liners, compost bulking agents, various manufactured products, energy recovery and even as artificial reefs for aquatic life. For traditional wastewater filtration, gravity downflow granular filters using sand or anthracite as a medium are commonly used. One major problem with these filters is that upon backwashing the particles, the larger ones settle at a greater rate than the smaller. The Penn State researcher explains that this causes the top of the filter bed to hold the smallest medium particles and the bottom to hold the largest with the small medium particles or top layer of the filter tending to become clogged quickly. In his research, he has proved that crumb rubber is not a rigid material; instead it can be easily bent or compressed. Through the crumb rubber method, the larger solids are removed at the top layer of the filter and the smaller solids at a lower level, greatly minimizing the clogging problem. Several studies conducted by Xie show that the crumb rubber filter is much more cost effective than conventional sand or anthracite filters. Because of substantially higher water filtration rates and lighter weight in comparison to sand or anthracite, crumb rubber filters may also be used in a mobile treatment unit for disaster relief operations, he adds. Because the crumb rubber is compressible, the porosity of the particles is decreased which resembling an ideal filter medium configuration. It can then be used at higher filter rates while performing similarly to other media now in use. The crumb rubber media provide better effluent qualities and larger media allow longer filter runs at higher flow rates." Category: Colorado Water 9:30:12 AM     Chimney Hollow reservoir? Western slope officials are balking at the size of a newly proposed Chimney Hollow reservoir, according to the Longmont Times-Call. From the article, "Plans that would help the city store up more water for use in dry years are being challenged by a West Slope organization that says the project is far larger than what it agreed to. Longmont is one of the players - along with the Northern Colorado Water Conservancy District and a handful of cities that includes Erie and Loveland - behind plans to build a $220 million reservoir near Carter Lake to store Windy Gap water rights diverted from the Colorado River. Some of that water now runs downstream in wet years because there's nowhere to store it. The proposed Chimney Hollow reservoir between Loveland and Longmont is an integral part of plans to ensure the northern Front Range has sufficient water for all the development public officials are permitting, officials say. However, the Colorado River Water Conservation District has asked the state engineer to rule that the proposed 90,000-acre-foot reservoir is too different from the original 11,000-acre-foot reservoir. Chris Treese, Colorado River Water Conservation District spokesman, said the larger reservoir was not part of the original agreements made between the districts in 1980 and 1985... "Although the Glenwood Springs-based water district does not plan to sue the Northern Colorado Water Conservancy District over the matter, Treese said his district believes the change requires a new Water Court decree. Officials with the NCWCD say they have met all the terms of the agreement, including several measures that benefit the Western Slope. 'It's not going to adversely impact the West Slope,' NCWCD manager Eric Wilkinson said. 'Our participants and board are somewhat disappointed and puzzled that the river district doesn't want to honor the agreements in place.' State engineer Hal Simpson said he is reviewing the issue and expects to reach a decision by mid-December. The federal Bureau of Reclamation asked Simpson to review the project." Category: Colorado Water 8:20:03 AM

© Copyright 2006 John Orr. Last update: 12/29/06; 12:27:29 PM.