Split pond design and the use of Nano TiO2 for stormwater quality improvement

Abstract

This research was proposed to enhance stormwater quality due to limited freshwater resources considering water crisis and global warming and public health. Applied treatment methods to improve quality of stormwater; as a source of freshwater; especially in detention ponds are not good enough and problems related to using contaminated water is increasing. The research contains two new concepts in detention pond designation for outflow quality improvement. First flush separation using a channel-partition filled with stratified sand filter inside the pond for suspended solids removal maximization, and second applying immobilized Nano-TiO2 concrete mixture as a cover on the partitions and pond body for its contamination removal and oxidation abilities fruition. The photo-degradation of COD, phosphate and nitrate in stormwater in the photocatalytic reactor wet detention pond using Nano titanium dioxide (TiO2) was investigated in the presence of natural ultraviolet (UV) from tropical sunlight in Malaysia. The observations were compared to regular pond at scale model in UTM laboratory. Two forms of TiO2 Nano powders (Anatase with average diameter of 25 nm and Rutile 100 nm Nano particles) were used in the two different types of concrete that is used ordinary portland and white cement. For weightage optimization purpose they were mixed at three different mixtures of 3%, 10% and 30% of Nano-TiO2 weightage and cement as a thin cover to surround the body of the pond and partitions. Experiments with and without the catalyst were carried out for comparison and control. “Results revealed that applying the channel partition can physically increase the TSS removal rate up to 92%. More over utilization of various weight of Nano-TiO2 in average can chemically reduce phosphate, nitrate and COD up to 40%, 11%, and 43% within two days and 83%, 30% and 68% within three weeks, respectively'.