Photocatalytic oxidation of dairy effluent with UV lamp or UV light-emitting diode module and biological treatment processes

The objective of this study was to develop a novel and simple-operated treatment system for refining dairy farm effluent after conventional dairy wastewater treatment system. Experimental results showed that average removal efficiency of COD, BOD, and SS in the effluents of a dairy farm was 72, 98, and 79%, respectively, using a combined photocatalytic and biological reactors. Removal efficiency of calculated conductivity value seems to be closely related to the removal efficiency of NH4+, PO43−, and Mg2+ when using the photocatalytic UV lamp reactor only. However, average removal efficiency of COD, BOD, and SS in the dairy farm effluent was 53, 62, and 62%, respectively, with the photocatalytic UV LED reactor. In summary, removal efficiency of BOD, COD, SS, and EC in photocatalytically treated dairy farm effluent with UV lamp reactor was higher than that with photocatalytic UV LED reactor. In addition, removal efficiency of COD and BOD with a combined photocatalytic and biological treatment system was higher than that using a photocatalytic oxidation reactor only. Thus, the combined system can provide dairy cattle farmers to refine and recycle their effluents.