Evaluating above-ground permeable reactive barrier materials: Sorption efficiencies for orthophosphate-P and ammonia-N onto zeolite and limestone

ENVR 39

Rajani Srinivasan, rsrinivasan@brc.tamus.edu, Dennis Hoffman, dhoffman@brc.tamus.edu, and June Wolfe III, jwolfe@brc.tamus.edu. Blackland Research and Extension Center, Texas A&M University System, 720 East Blackland Road, Temple, TX 76502
Laboratory batch experiments were conducted to study the adsorption efficiency of limestone (L) and zeolite (Clinoptolite) (Z) constituting the Above Surface Permeable Reactive Barrier System (APRBs) for removal of ammonium-N and orthophosphorus-P. The effect of the size of the rocks, contact time, pH and temperature were studied. The major emphasis was to study their adsorption efficiency in lesser contact time because the contact of the runoff water in the field with the APRBs would be ~ 5 minutes. Maximum removal of PO42--P (70.34%) and NH4-N (41.30%) was seen at 45°C and 25°C, respectively, in five minutes with a pH range of 8-9. Optimum adsorbent concentration was 0.3 ppm with 20g limestone and 10 g of zeolites. Combinations of crushed zeolite and limestone show promise for use in above-ground PRB systems. APRBs can be used to remove dissolved nutrients from runoff and protect surface water resources from eutrophication.
 

Advances in Adsorption Processes for Drinking Water Treatment and Sourcewater Protection
1:30 PM-5:10 PM, Sunday, April 6, 2008 Morial Convention Center -- Rm. 236, Oral

Division of Environmental Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008