Treatability Study of a Seafood-Processing Wastewater

Abstract

The unique characteristics of seafood-processing wastewater require a treatability study be performed. Wastewater from seafood-processing contains high concentrations of nitrogen and suspended solids along with large volumes of wastewater. This treatability study was undertaken using a 10 L per day, bench-scale, modified Ludzack–Ettinger (MLE) process that was designed, constructed, and operated for approximately eight (8) months. Influent and effluent data collected on the system included: chemical oxygen demand (COD), total suspended solids (TSS), total Kjeldahl nitrogen (TKN), ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, total nitrogen (TN), pH, total phosphorus (TP), dissolved oxygen (DO), alkalinity, and temperature. All analyses were performed in accordance with Standard Methods.[1] Influent characteristics ranged from 892 to 7470 mg/L COD, 36 to 1037 mg/L TKN, 70 to 3450 mg/L TSS, and 39 to 86 mg/L TP. Mean cell residence time (MCRT) served as the primary control parameter with average MCRTs of 5.3, 6.4, 8.5, and 30.9 days observed during the study. Biokinetic coefficients determined at 25°C during the study included a yield coefficient (Y) of 0.42 mg TSS/mg COD and an endogenous decay coefficient (k d) of 0.22 days−1. The average, overall observed specific nitrification rate (SNR) and average observed specific denitrification rate (SDNR) was 0.084 days−1 and 0.051 days−1, respectively. UV-Vis spectroscopy was found to have a potential for characterizing the biological treatment process. The MLE is an effective method of biologically treating a seafood-processing wastewater.