|Klasson, K Thomas|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/26/2012
Publication Date: 10/4/2012
Citation: Klasson, K.T., Ledbetter, C.A., Lima, I.M., Uchimiya, S.M. 2012. Removal of dibromochloropropane from drinking water: laboratory and field experiences [abstract]. Proceedings of the 30th International Activated Carbon Conference, October 4-5, 2012, Pittsburgh, PA.
Technical Abstract: Dibromochloropropane (1,2-dibromo-3-chloropropane or DBCP) is regulated by the U.S. Environmental Protection Agency under the National Primary Drinking Water Regulations to a maximum of 0.2 µg/L (0.2 ppb) in drinking water. DBCP was primarily used as an unclassified nematicide for vegetables and perennial crops and is no longer produced in the U.S. Its use contaminated some groundwater and aquifers of nearby agricultural communities. Here, we describe the performance of activated biochars made via pyrolysis and steam activation of almond shells, available locally in proximity to contaminated areas, in removing DBCP. The specific surface area (BET) was approximately 360 m2/g of activated biochar and the majority of pore diameters were less than 2 nm, indicating that most of the pores were micro-pores. The yield of activated biochar from the raw material was 23% (dry basis) and fixed carbon content (from proximate analysis) increased from 21% (dry-basis) in the almond shells to 66% in the activated biochar. The ash content of the activated biochar was 19%. Using a 5000 ppm DBCP standard, the well water (and in some cases deionized water) was spiked to a variety of concentrations. Results showed that regardless of the background composition (deionized water or well water) the loading capacities were the same and appeared to follow a typical isotherm pattern. Based on these results, we concluded that steam-activated biochar made from almond shells could be used as a DBCP adsorbent from well water intended for consumption. We installed activated biochar columns at a field site in California and operated the system for 6 months, treating water to drinking water standards. A column breakthrough curve was collected and mathematically modeled to determine if the breakthrough profile was the result of mass-transfer limitation external to, or internal to, the particles.