Waste Water Treatment Technology for Small Scale Pulp and Paper Mills in Thailand (Part 2)

The authors surveyed the present status of wastewater treatment in several handmade paper mills in Thailand. The quality of wastewater, it was made clear that the COD and color improved considerably by combined treatment of anaerobic process with aerobic one. Ozone oxidation under UV irradiation improved water quality more rapidly than ozone treatment alone (Part 1 and Part 2).In the present study, the authors carried out TiO2 photo-catalytic oxidation under artificial UV lamp or solar light as light sources. Wastewater sample which contained organic substances as COD 100 mg/L and colored in pale brown was collected from final aerobic ponds in small pulp and paper mills. UV irradiation (artificial UV light or solar light) with TiO2 catalyst decreased COD more rapidly and eliminated color more effectively than UV treatment alone. The deceleration degree of dyestuff gave extremely excellent results by TiO2 photo-catalytic oxidation using UV lamp or solar light.In conclusion, it was suggested that organic compounds given as COD and color caused by dyestuff in wastewater can be decomposed by biological treatment of combined anaerobic-aerobic process, followed by TiO2 photo-catalytic oxidation treatment under artificial UV light or solar light in relatively short time. This is a kind of non-chemical process in wastewater treatment.