Ozonation improves physical attributes in domestic sewage effluent

Abstract Root Zone Wastewater Treatment (RZWT) is an option of natural wastewater treatment widely studied throughout the world, being a technology based on physical, chemical and biological processes. However, there are some attributes in effluent that occasionally are not eliminated by RZWT. In this context, the use of ozone may contribute to mineralization, disinfection, detoxification, and, especially, color and turbidity removal. Ozone is an excellent oxidant, with great potential to reduce color, turbidity and other attributes in liquids, such as in wastewater treatment. This paper evaluated the effect of different ozone exposure times (0, 30, 60, 90, 120 and 150 minutes) and the application of different dosages of ozone (0, 4, 10, 17, 25 and 35 mg L-1 of O3) on Hydrogeonic Potential (pH), Electrical Conductivity (EC), Dissolved Oxygen (OD), Total Alkalinity (Alk.), Sodium (Na) and Potassium (K) in domestic sewage effluent treated by the RZWT. Different exposure times and ozone dosages did not influence the attributes Potassium, Sodium, Ammonia and Total Solids. Color and turbidity decreased, while pH, Alkalinity and Dissolved Oxygen increased at all exposure times and O3 dosages in relation to the non-ozonized effluent.

摘要 根区污水处理（Root Zone Wastewater Treatment, RZWT）是全球范围内广受研究的自然污水处理技术之一，其依托物理、化学与生物过程实现污水净化。但该技术偶尔无法去除出水中的部分指标污染物。在此背景下，臭氧氧化技术可辅助实现矿化、消毒、解毒，尤其可有效脱色与除浊。臭氧作为一类优异的氧化剂，在液体（如污水处理场景）中具备降低色度、浊度及其他污染物指标的巨大潜力。本文针对经RZWT处理后的生活污水出水，评估了不同臭氧接触时长（0、30、60、90、120及150分钟）与不同臭氧投加量（0、4、10、17、25及35 mg·L⁻¹ O₃）对其氢电位（Hydrogeonic Potential, pH）、电导率（Electrical Conductivity, EC）、溶解氧（Dissolved Oxygen, OD）、总碱度（Total Alkalinity, Alk.）、钠（Sodium, Na）与钾（Potassium, K）的影响。研究结果表明，不同臭氧接触时长与投加量对钾、钠、氨氮及总固体含量无显著影响；相较于未经过臭氧氧化的出水，所有试验条件下的出水色度与浊度均有所降低，而pH、总碱度与溶解氧均有所提升。