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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Commodity Utilization Research » Research » Publications at this Location » Publication #163962
Title: THE USE OF NUTSHELL CARBONS IN DRINKING WATER FILTERS FOR REMOVAL OF CHLORINATION BY-PRODUCTS

Author
item AHMEDNA, MOHAMED - N. CAROLINA A&T UNIV
item Marshall, Wayne
item HUSSEINY, ABDO - TECHNOLOGY INT'L.
item GOKTEPE, IPEK - N. CAROLINA A&T UNIV
item RAO, RAMU - LSU AG CENTER

Submitted to: Journal of Chemical Technology & Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/23/2004
Publication Date: 10/25/2004
Citation: Ahmedna, M., Marshall, W.E., Husseiny, A.A., Goktepe, I., Rao, R.M. 2004. The use of nutshell carbons in drinking water filters for removal of chlorination by-products. Journal of Chemical Technology & Biotechnology. 79:1092-1097

Interpretive Summary: Despite the assurance offered by numerous regulatory agencies that the domestic drinking water in the United States is safe, many consumers are wary of tap water and question its quality and health effects. As a result, American households spend over $5 billion annually on bottled water and home water treatment systems. Therefore, there is a growing need to produce water filters that are low cost and effective at removing potentially harmful components in drinking water. Scientist at the USDA-ARS, Southern Regional Research Center in collaboration with scientists at Technology International Inc. of Virginia, LaPlace, LA and the Department of Food Science, Louisiana State University, Baton Rouge, LA have developed granular activated carbons from almond shells, English walnut shells and pecan shells that are particularly effective at sequestering carcinogenic, organic contaminants called trihalomethanes (THMs) that arise from the routine chlorination of drinking water. These carbons removed more THMs than four different commercial water filters and were considerably less costly to produce than the retail price of the commercial filter units. Nutshell carbons appear to be excellent substitutes for commercial coal-based carbons and coal-based carbons combined with ion exchange resins in THM removal from drinking water and should be considered as an alternative to existing commercial home filters.

Technical Abstract: Chlorination of drinking water is a common practice by numerous municipalities in the United States (US) to safeguard their water supplies. However, the chlorine used can chemically react with organic components in the drinking water to produce unwanted chlorination by-products. The objective of this investigation was to evaluate the use of granular activated carbon produced from nutshells (almond, English walnut, pecan) in a point-of-use (POU) water filtration system designated "Envirofilter" and to determine its efficacy in removing select, potentially carcinogenic chlorination by-products, namely, the trihalomethanes (THMs) bromodichloromethane, bromoform and dibromochloromethane. The POU water filtration system that contained the nutshell-based carbons was designated "Envirofilter" and adsorption efficiencies of this system were compared to that of four commercially available POU home water filter systems, namely, BRITA, Omni Filter, PUR and Teledyne Water Pik. Eight different "Envirofilters" were constructed of individual or binary mixtures of carbons produced from acid-activated almond or pecan shells and steam-activated pecan or walnut shells and evaluated for adsorption of the three chlorination by-products. The results indicate that only two of the eight "Envirofilters" failed to remove more THMs than the commercial POU systems. In both cases, these filters contained carbons with either 100% acid-activated almond shells or 100% acid-activated pecan shells. All six of the other filters contained carbons with either 50% or 100% steam-activated pecan shells or steam-activated walnut shells. Therefore, "Envirofilters" appeared to depend on the presence of steam-activated nutshell carbons for their success. The six effective "Envirofilters" reduced THM levels below the Maximum Contaminant Levels (MCL) required by the US Environmental Protection Agency (US EPA). Based on these results, these six "Envirofilters" may be considered as a replacement for existing commercial filter systems because of their efficacy and projected cost.