Treatment of Low C/N Ratio Monosodium Glutamate Wastewater in Suspended Carrier Biofilm Process

This paper presented the operation results in the full-scale suspended carrier biofilm (SCB) process for the treatment of the low C/N ratio monosodium glutamate wastewater (MSGW). After the long-term operation of 185 days, the removal efficiencies of COD, total nitrogen (TN) and ammonia nitrogen (AN) achieved above 89.5%, 91% and 92.5% at the influent organic loading rate (OLR) of 1.25-1.8 kgCOD/(m³·d), dissolved oxygen (DO) of 3.0-5.0 mg/l, ambient temperature of 25-28°C, and hydraulic retention time (HRT) of 0.24-0.28d. The average removal rates of AN and TN were 0.348 kgN/(m³·d) and 0.445 kgN/(m³·d) and the effluent NO₃^--N and NO₂^--N concentration were lower than 6.9 mg/L and 0.15 mg/L without nitrate and nitrite accumulation at the low TOC/TN and TC/TN ratios of 0.59 and 3.17 in the optimum operation. The study demonstrated DO and temperature were the key operational parameters in the performance of SCB process for nitrogen removal in the treatment of low C/N ratio MSGW.