Bruce Backus

Carbon-to-Nitrogen Ratio and Hydraulic Retention Time Effect on the Anaerobic Digestion of Cheese Whey

ABSTRACT SIXTEEN 1-L digesters were used to test four carbon-to-nitrogen ratios of 8.4, 13.9, 22.2 and 27.6 and four hydraulic retention times of 12, 18, 24 and 30 days on the efficiency of digester operation. Percent methane in the biogas and methane production were dependent on both carbon-to-nitrogen ratio and hydraulic retention times. Percent chemical oxygen demand reduction, volatile solids removal, total volatile acids concentrations, digester pH and amount of sodium hydroxide solution needed to control digester pH were dependent on hydraulic retention time only.

Regulatory compliance and training assessment tools

To help researchers (faculty, staff, post doctoral fellows and graduate students) better understand their many regulatory compliance and training requirements, including those beyond environmental health and safety (EH&S), Washington University in St. Louis and the University of Pennsylvania developed on-line tools to guide their staff through the process. The tools are analogous to “tax preparation” software with questionnaires that direct faculty, staff and students to their required training or compliance requirements. Examples of the two tools are provided along with examples of how the tools are used to improve compliance.