Abstract 1211 Determination of efficient alternative carbon sources for wastewater denitrification

Wastewater is high in nutrients that are harmful to the environment if not processed. Water reclamation facilities culture microbes to denitrify the nutrients. To aid in the denitrification of wastewater, organic components are added in the form of a carbon source. The primary carbon source used at the studied reclamation facility is Micro-C™, a proprietary blend of crude glycerin. The composition of Micro-C™ is unknown, which presents challenges in fully committing to its usage, so alternatives need to be identified. Micro-C™ was collected from the wastewater facility, while crude glycerin was collected from three industrial producers. The three crude glycerins are named Crude Glycerin A, B, and C. Mixed liquor was sampled five days a week for eight weeks from the treatment plant. The validity of each sample was assessed using the dissolved oxygen concentration (DO), the pH, and the temperature. Mixed Liquor Suspended Solids (MLSS) were calculated for each sample. The mixed liquor was split into two beakers, one dosed with ∼50mg/L of a glycerin sample and ∼10mg/L of a biological nutrient (either NO3 or NO2). The other was dosed with ∼10mg/L of the same nutrient and used as a control. Immediately after dosing, and every 30 minutes for two hours, the nutrient concentration was tested. The specific denitrification rate was calculated from the nutrient concentrations and the MLSS and normalized by carbon source concentration. Micro-C™ was the most efficient at 2.8*10-2 (mg/g MLSS/hr)/mg/L. Crude Glycerin C was the least efficient at 8.2*10-4 (mg/g MLSS/hr)/mg/L. Crude Glycerins A and B were comparable to Micro-C™ in efficiency, at 2.5*10-2 and 2.2*10-2 (mg/g MLSS/hr)/mg/L respectively. Crude Glycerins A and B present accessible and affordable alternatives to Micro-C™. The dosage concentration of Crude Glycerin C was miscalculated and more testing is needed to confirm its efficiency at the same dosages as the other carbon sources. In conclusion, Micro-C™ is the preferable carbon source for denitrification. In the absence of Micro-C™, Crude Glycerins A and B are acceptable alternatives.