title: The use of crab-shell chitin for biological denitrification: batch and column tests.
abstract: Crab-shell chitin (SC-20) was evaluated for its ability to enhance biological denitrification in bench-scale tests. In the presence of SC-20, highly reducing conditions were generated, supporting both denitrification and sulfate reduction of aerated water. Rapid degradation of protein in SC-20 was observed to cause an initial high release of ammonium and carbon, while a slower, continuous release of calcium carbonate from the crab shell maintained the pH near 9 throughout the tests. In batch tests, denitrification rates of 2.4+/-0.2 mg N/L-d were obtained. Columns receiving a continuous nitrate load of 24.5 mg N/L-d sustained complete denitrification for an average of 149 d (250 pore volumes). The denitrification rates and longevity of SC-20 chitin are comparable to, or better than, those previously reported for other polymeric substrates. This, in addition to its particle size, non-swelling nature, and ease of delivery in slurry form make SC-20 an attractive electron donor source for groundwater bio-denitrification.
authors.affiliation: Department of Civil and Environmental Engineering, The Pennsylvania State University, 212 Sackett Building, University Park 16802-1408, USA.
authors.forename: Mary Ann
authors.initials: MA
authors.lastname: Robinson-Lora
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Brennan
mesh_terms: D000818:Animals; D001673:Biodegradation, Environmental; D019149:Bioreactors / Q000382:microbiology*; D003386:Brachyura / Q000737:chemistry*; D002686:Chitin / Q000378:metabolism*; D009566:Nitrates / Q000302:isolation & purification* / Q000378:metabolism*; D012867:Skin / Q000737:chemistry*
chemical_list: D009566:Nitrates; D002686:Chitin