Experimental Study On SCWO For Treatment Of Antibiotic Wastewater

Antibiotics have been recognized as a kind of emerging contaminants, because of its serious environment effect. Although the methods to treat antibiotic wastewater are diverse, choose an efficient processing one is very pivotal. Because the antibiotic wastewater is of high concentration of organic compounds, serious biological depressing characters, choose processing technology efficiency is key. Supercritical water oxidation (SCWO) is a kind of advanced oxidation technology, and there have been many researchers conducted studies on it. Mostly, targets are organic pollutants which are always difficult to degradation, toxic or harmful substances. The results are satisfactory. In this experiment, antibiotic wastewater was treated by continuous supercritical reaction equipment treatment, and the influence factors and reaction kinetics were analyzed.Firstly, regarded COD and NH3-N removal rate as the index, the treatment effect of supercritical water oxidation technology for antibiotic wastewater was examined. The results show that the effect is good. For example, in the condition of reaction time of60s, temperature of380℃, the pressure of25MPa, the initial concentration of COD of500mg/L, NH3-N Of40mg/L, H2O2(30%) of 7080mg/L, COD and NH3-N removal rate reached92.4%and72%respectively.Secondly, the influence of the parameters on the treatment effect was analyzed. The results showed that COD and NH3-N removal rate increased with residence time in the range of20-60s, but the pace of them were different with the different region. COD and NH3-N removal rate increased with temperature in the range of380-410℃, presenting linear relationship. In the vicinity of supercritical critical pressure, COD and NH3-N removal rate changed obviously. COD and NH3-N removal rate increased obviously with oxygen excess in the range of0-100%while did not change significantly when oxygen excess is more than100%. The initial concentration had a very small effect on COD and NH3-N removal rate.Then, the results of RSM analysis are just as following:①The effect of residence time and oxygen excess on the COD removal rate is relatively obvious.②Regression equation of RSM is:X-COD=81.89+31.48A+4.14B+18.84C-3.30AB+110AC-0.82BC-19.31A2-4.59B2-19.74C2(A, B, C represent residence time, temperature, oxygen excess respectively), and A, C, AC, A2, C2has a great effect on the experimental results.③The RSM optimization of the main parameters is of residence time of52.58s, temperature of392.54℃, oxygen excess of125.42%, the removal rate of COD is98.92%.Then, the power index method were used to study reaction kinetics, the kinetic equation is as follow:r＝1.211×103exp(-49.19×103/RT)[c0](1.405±0.040)-1(1-X)(1.405±0.040)...