Pretreatment of Afyon alcaloide factory's wastewater by wet air oxidation (WAO)

In this study, pretreatment of Afyon (Turkey) alcaloide factory wastewater, a typical high strength industrial wastewater (chemical oxygen demand (COD)=26.65 kgm(-3), biological oxygen demand (BOD(5))=3.95 kgm(-3)), was carried out by wet air oxidation process. The process was performed in a 0.75 litre specially designed bubble reactor. Experiments were conducted to see the advantages of one-stage and two-stage oxidation and the effects of pressure, pH, temperature, catalyst type, catalyst loading and air or oxygen as gas source on the oxidation of the wastewater. In addition, BOD(5)/COD ratios of the effluents, which are generally regarded as an important index of biodegradability of a high-strength industrial wastewater, were determined at the end of some runs. After a 2h oxidation (T=150 degrees C, P=0.65 MPa, airflowrate=1.57 x 10(-5)m(3)s(-1), pH=7.0), the BOD(5)/COD ratio was increased from 0.15 to above 0.5 by using the salts of metals such as Co(2+),Fe(2+),Fe(2+)+Ni(2+),Cu(2+)+Mn(2+) as catalyst.     

Wet air oxidation of polyether solutions

This paper studied the characteristics of wet air oxidation (WAO) on polyether as non-ionic surfactant and analyzed its main intermediates. The results showed that, WAO was an effective method to treat non-ionic surfactants like polyether; temperature played a decisive role throughout the process: the COD removal percentage within 2 h was only 33.5% at 160 °C, 57.2% at 200 °C, and 94.4% at 240; fatty acid was the major intermediate, and oxidation of acetic acid was the key rate-determining step during fatty acid oxidation, and the oxidation of fatty acid could be accelerated by rising the temperature as well as elongating the reaction time. Meanwhile, oxidative decomposition of polyether and oxidation on fatty acid were the rate-determining steps to the whole WAO process, the oxidation of polyether was relatively more limited at lower temperature; on the contrary, the oxidation of fatty acid and other organics was obviously more limited at higher temperature.     

WAO法处理中进水浓度对废水浊度去除的影响

采用湿式空气氧化法,对高浓度难生化有机废水进行处理.试验研究在湿式空气氧化法处理有机废水中不同进水浓度对浊度去除率的影响,通过测定水样浊度、浊度去除率的变化,发现,WAO法对不同进水浓度废水的处理效果都是随着反应时间增加而增加,而进水浓度越小,WAO法处理有机废水的效果越好.结果表明,当进水浓度COD=1000 mg/...     

WAO和CWAO污水净化技术

湿式空气氧化（WAO）是指在一定的温度和压力下，废水中的有物或无机物与空气中的氧发生的液相反应。利用WAO工艺可在180－315℃和2－15MPa的条件下净化工业废水和油渣，绝大多数复杂有机化合物被氧化为二氧化碳和水及生物可降解的较简单形式的化合物。综述了WAO工艺及近期发展情况。与传统的WAO相比，催化湿式空气氧化（CWAO）需要更温和的反应条件，但可明显提高液相氧化效率。CWAO法的解决日益突出的工业废水和油渣问题提出了崭新的技术途径。     

Treatment of oily sludge by two-stage wet air oxidation

Oily sludge produced in petrochemical industries contains a large amount of toxic and hazardous substances. High oil sludge yield and high treatment cost have become major obstacles to the development of the petrochemical industry. In this study, the treatment and disposal of oily sludge using the wet oxidation method was investigated. Firstly, the orthogonal optimization experiment was designed to discuss the influence of reaction time, reaction temperature, oxidant amount, and emulsion splitter amount on the removal efficiency of oil and sludge volume. On this basis, a two-stage wet air oxidation method was employed to treat oily sludge. The results show that the two-stage oxidation method could remove 93.1% oil from the oil sludge and reduce the volume of oil sludge by 85.4%. Furthermore, the oil sludge treated with wet oxidation could be more easily separated from water, and the waste oil could be recycled. The proposed two-stage wet oxidation method shows excellent performance in treating oily sludge, from which resources can be recycled while reducing the amount of sludge.