@article{sadri_staley_barlaz_xu_hater_2010, title={Effect of an acidic and readily-biodegradable non-hazardous industrial process waste on refuse decomposition}, volume={30}, ISSN={["0956-053X"]}, DOI={10.1016/j.wasman.2009.06.026}, abstractNote={Non-hazardous industrial process wastes are receiving increased interest from landfill owners, especially with respect to bioreactor operation. These wastes could benefit bioreactors as they represent sources of liquid, nutrients, and/or substrate as well as revenue. However, landfill operators should exercise caution in accepting these wastes, as some could have detrimental effects on refuse decomposition. In this research, the use of laboratory-scale tests to evaluate the effect of one such waste on refuse decomposition is demonstrated. The waste evaluated, referred to as burnt sugar, is an acidic byproduct of corn-based polylactic acid production and represents a source of readily-biodegradable carbon. Lactic acid was the primary constituent of the BS at 0.73 g/g and the COD was measured at 1230 mg COD/g. Testing protocols were adapted to address the specific concerns surrounding the material. Abiotic dissolution tests conducted at mesophilic temperatures indicated that the majority of the waste dissolved into leachate recirculated over a layer of the waste within several days. Abiotic mixing tests suggested that the waste would acidify refuse to pH 6.41 at a loading of 21.9 g/dry kg refuse. However, in biologically active tests, the refuse was able to convert loadings as high as 196.7 g/dry kg refuse to methane. As the loadings increased toward and beyond this level, pronounced detrimental effects to the refuse ecosystem were observed, including a decrease in pH, accumulation of volatile fatty acids and COD, and lag in methane production. The results suggested that actively decomposing refuse has the potential to attenuate relatively high loading of a rapidly degradable but acidic substrate. Nonetheless, caution in the implementation of a field program to accept rapidly biodegradable acidic wastes is critical.}, number={3}, journal={WASTE MANAGEMENT}, author={Sadri, Ahmad and Staley, Bryan F. and Barlaz, Morton A. and Xu, Fang and Hater, Gary R.}, year={2010}, month={Mar}, pages={389–395} }
 @article{bhandari_xu_koch_hunter_2009, title={Peroxidase-Mediated Polymerization of 1-Naphthol: Impact of Solution pH and Ionic Strength}, volume={38}, ISSN={["0047-2425"]}, DOI={10.2134/jeq2008.0426}, abstractNote={Peroxidase‐mediated oxidation has been proposed as a treatment method for naphthol‐contaminated water. However, the impact of solution chemistry on naphthol polymerization and removal has not been documented. This research investigated the impact of pH and ionic strength on peroxidase‐mediated removal of 1‐naphthol in completely mixed batch reactors. The impact of hydrogen peroxide to 1‐naphthol ratio and activity of horseradish peroxidase was also studied. Size exclusion chromatography was used to estimate the molecular weight distribution of oligomeric products, and liquid chromatography/mass spectrometry was used to estimate product structure. Naphthol transformation decreased with ionic strength, and substrate removal was lowest at neutral pHs. Solution pH influenced the size and the composition of the oligomeric products. An equimolar ratio of H2O2:naphthol was sufficient for optimal naphthol removal. Polymerization products included naphthoquinones and oligomers derived from two, three, and four naphthol molecules. Our results illustrate the importance of water chemistry when considering a peroxidase‐based approach for treatment of naphthol‐contaminated waters.}, number={5}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Bhandari, Alok and Xu, Fangxiang and Koch, David E. and Hunter, Robert P.}, year={2009}, pages={2034–2040} }