Application of a novel, continuous-feeding ultraviolet light emitting diode (UV-LED) system to disinfect domestic wastewater for discharge or agricultural reuse

WATER RESEARCH

卷:153

Article

Thi Minh Hong Nguyen¹  Suwan, Poonyanooch¹  Koottatep, Thammarat¹  Beck, Sara E.^1,2 

[1] Asian Inst Technol, Sch Environm Resources & Dev, Environm Engn & Management Program, POB 4, Khlong Luang 12120, Pathumthani, Thailand

[2] Eawag Swiss Fed Inst Aquat Sci & Technol, Dept Environm Microbiol, CH-8600 Dubendorf, Switzerland

关键词: UV-LEDs;    Flow-through;    Decentralized;    Domestic wastewater;    Water reuse;    Fouling;   

DOI  :  10.1016/j.watres.2019.01.006

来源: Elsevier

【 摘 要 】

In many low-income countries, the poor conditions of sanitation systems have been a significant cause of mortality since they accelerate waterborne disease transmission. Developing sanitation systems in these countries is a pressing concern in both the public and private sectors. This research investigated a decentralized domestic wastewater treatment system using ultraviolet light-emitting diodes (UV-LEDs). Although UV-LED disinfection has become more widespread in recent years, it is a novel approach for domestic wastewater treatment. Domestic wastewater was pretreated by a low-cost pretreatment system with an inclined settler and a sand filter prior to feeding a novel flow-through UV LED reactor. At an inlet flow rate of 30 L/h, the COD, TSS, and turbidity of the effluent were 17.7 mg/I, 3.0 mg/I, and 3.9 NTU, respectively. UV transmittance at 285 nm was enhanced from 29.1% to 70.4%, improving the influent quality for UV LED disinfection. The flow-through UV LED reactor was operated at various flow rates from 10 to 50 mL/min, resulting in applied UV doses of 69.4 to 47.8 mJ/cm(2) respectively. These doses are sufficient for inactivating total coliforms in the wastewater to meet the water reuse guidelines for agriculture for both processed food crops and non-food crops. Fouling, which was observed starting at 2 d of operation, decreased the disinfection efficacy to 27% after 25 days of continuous operation. Of the fouling layer, 67% was attributed to organic matter, in contrast to previous fouling studies with mercury UV lamps in which the fouling layer consisted primarily of inorganic compounds. The fouling was reversed by off-line citric acid cleaning for 4 h after every 400 h of continuous operation. (C) 2019 The Authors. Published by Elsevier Ltd.

【 授权许可】

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