One of the best solutions for the deficiency of clean water, especially for developing countries, is rainwater disinfection. In the past decades a lot of studies have been made to develop photocatalytic processes using TiO2 determining the performance on their surface oriented photocatalysis. However, most of these researches failed to consider the economical aspect as well as the effectiveness on the disinfection to antibiotic resistance genes. On the other hand, due to the issues of climate change and increased impermeable layer in urban area, flooding prevention is the best solution in water management systems. To remedy these two problems, a roof-harvested rainwater storage system was designed. In addition, a breakthrough technique using a solar simulator with self-rotating TiO2 nanotubes, to apply a photocatalytic system in disinfecting storage rainwater harvested from roof, was established. Roof-harvested storage rainwater was analysed for TN, TP, SS and COD. Aside from these parameters, Escherichia coli (with multidrug resistant pB10 plasmid) was added to the sample. Samples were injected to the self-rotating TiO2 nanotube reactor system with exposure time of 0 to 360 min and 7 different setups. Results show that the developed system has increased disinfection properties compared to negative samples, though the presence of antibiotic resistant bacteria.

The presence of pharmaceuticals in the environment has led to apparent toxicity with different aquatic species. Clarithromycin, for example, is used in treating respiratory tract infections, has been recently found in the surface waters and rivers which might threaten non-targeted organisms in these matrices. In this study, a model vertebrate Danio rerio (zebrafish) was exposed to 100ppb clarithromycin for 72 hours to evaluate acute toxicity through significantly affected metabolic compounds in the fish’s pathway. Metabolites obtained from q-TOF LC/MS were identified and mapped with the zebrafish’s metabolic pathway using Metlin, and KEGG respectively. 335 compounds are believed to have been significantly altered by the acute exposure of the antibiotic with the fish. The most affected pathways are ABC transporters, steroid hormone biosynthesis, arachidonic acid metabolism, purine metabolism, and biosynthesis of amino acids. With the said findings, it can be concluded that, although concentration of some pharmaceuticals may be as low as the one used in this study, its effects on the aquatic species exposed to it might be significant and should be given immediate attention