Study On The Biological Treatment Of Wastewater Of TNT/RDX Ammunition Loading

In this thesis, the removal of TNT,RDX and TNT/RDX in munitions loading wastewater by anaerobicand aerobic bio-film was investigated in detail, and then, a biochemical treatment process of TNT/RDX ammunition loading wastewater was designed according to the results. In addition, the process was verified and optimized through the practical ergineering applications of ammunition loading wastewater in amunition factory.The biodegradability and operating conditions of biological treatment unit of TNT,RDX and TNT/RDX wastewater were investigated firstly. For TNT wastewater (2.0～15.0 mg/L), the acclimation time of anaerobic and aerobic sludge were both in 30 d; for RDX wastewater (1.0～8.0mg/L), the acclimation time of anaerobic and aerobic were 40 d and 65 d, respectively; and for TNT/RDX wastewater (2.0～15.0/1.0～8.0 mg/L), the acclimation time of anaerobic was 80 d, while the aerobic required more than 3 months. After the acclimation, 36h and 48h were required to achieving complete degradation in the anaerobic and aerobic conditions for TNT wastewater (15.0 mg/L), respectively; while for the RDX wastewater (5.0 mg/L),60 h and 144 h were required, respectively. For the mixture wastewater of TNT/RDX, the initial concentration of RDX was fixed 5.0 mg/L, the effection of the concentration of TNT (from 3.6 to 15.0 mg/L) on the degradation pefermance was researched. The results showed that, comparison to the single component wastewater, there wasn't obviously change for the degradation rate of TNT, while it was required 120～336 h for RDX to meet the emission standand.The biological combine process of anaerobic and aerobic was designed to biodegrade TNT/RDX mixed wastewater. The influent concentration of COD and NH3-N were 250mg/L and 30mg/L, respectively, and the HRT of anaerobic and aerobic were 96 h and 48 h, respectively. When the concentration ratio of TNT/RDX increasing from 3.0/2.0 (mg/L) to 7.0/5.0 (mg/L), the effluent of TNT was degraded completely, however, that of RDX was above the emission standard. A novel process of reflux was designed, namely,15% of reflux ratio of the sludge in sedimentation to the equalization basin (which in a anoxic situation), and 100% of reflux ratio of aerobic effluent in 6 h per day to the anaerobic pond. In the above novel process, the HRTs of anoxic tank (equalization basin), anaerobic tank and aerobic tank were set in 36 h,72 h and 36 h, respectively, and the concentration ratio of TNT/RDX was in 10.0/7.0 (mg/L). In that condition, the effluent concentrations of TNT, RDX, COD and NH3-N were 0.0,0.3,11.5 and 3.2 mg/L, respectively, much below than the emission standards.Based on the experiment results, a treatment system of anoxic-anaerobic-aerobic biological with a filtration system was designed fo ra really ammunition loading wastewater. The influent concentrations of TNT, RDX, COD and NH3-N were in 0～12.0,0～8.0,150 and 30 mg/L, respectively. After 3 months commissioning the effluent quality met the emission standards, and passed the checking by the local Environmental Protection Agency.