Tropical stormwater chemical oxygen demand degradation using nano TiO2 in photocatalytic reactor detention pond

Abstract

Photo-degradation of stormwater chemical oxygen demand in wet detention pond was monitored. A scale model pond was converted to photocatalytic reactor using immobilized nano titanium dioxide (TiO2) as contamination remover under natural ultraviolet from tropical sunlight. Amount of chemical oxygen demand and dissolved oxygen within three weeks of experiment were measured with and without the catalyst for comparison and control. Mixture of nano TiO2 in white and ordinary portland cement was applied as a thin layer to surround the body of the pond (reactor). Three different mixtures of 3, 10 and 30 % weight of anatase and rutile form of nano TiO2 replaced with cement in concrete. Results shown that utilization of nano-TiO2 can decrease the amount of chemical oxygen demand up to 43 % within two days and 68 % during three weeks. While in the regular pond were 16 and 19 %, respectively. Also, the amount of dissolved oxygen in the pond using TiO2 was stable compared to 20 % oxygen depletion in normal pond after three weeks.