The removal of contaminants from consumable waters by the traditional water treatment techniques is highly difficult. Disinfection of water alludes to the inactivation or pulverization of unsafe living pathogenic beings, which living in the water. Occurrence of disinfection by products (DBPs) during disinfection normally demonstrates lethal impacts on human health. Granular activated carbon (GAC) has the oldest history of decreasing of organic matters, but its role is reducing by time. TiO 2 is used to accelerate the removal of the DBPs. TiO 2 nanoparticles have good adsorption phenomena on the removal of those organic compounds at various pHs and temperatures and give good results. This study proved that TiO 2 nanoparticles enhanced the efficiency of GAC to remove DBPs from water. While the elimination of trihalomethanes (THMs), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) using 0.5 g of GAC was determined as 61.7, 69.8 and 83.2% respectively, the elimination of them by 0.1 g of TiO 2 nanoparticles:GAC (1:1) was estimated as 100, 96 and 100%, respectively.

Chlorine is the most common disinfectant used in drinking water treatment because it is cheap and has an efficient germicidal ability. However, chlorine and organic matter reacting trihalomethanes (THMs) are suspected carcinogens. The major groups of disinfection by-products (DBPs) are THMs, haloacetic acids (HAAs), haloacetonitriles (HANs), and halogenated ketones (HKs). Exposure to these by-products increases the risk of cancers, abortion, low birth weight, and congenital disabilities. The wastewater contents of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), as the source of total organic carbon (TOC) compounds, are oxidized by chlorine to produce DBPs. This study aimed to monitor the seasonal levels of THMs in Egypt compared with international standards using capillary gas chromatography. Results revealed that THMs mean values vary between 9.26 to 35.86 μg/l, while dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) mean values vary between 3.82 to 17.74 μg/l and 4.41 to 13.25 μg/l, respectively. The maximum THM and TCAA values were observed during the summer, probably due to high temperatures. While the maximum DCAA values were observed during the autumn due to the high levels of raw water TOC. In conclusion, continuous monitoring of THM and its species is highly recommended, taking into consideration how climate can influence THMs formation.

Chlorination has significantly reducing the risk of pathogenic dirt but could pose a chemical hazard to human health due to formation of various disinfection by-products (DBPs). Chlorine dioxide is one of the most intriguing oxidants since it combines a high oxidation capacity with a minimal generation of harmful byproducts like chlorinated organics when used. As a result, it is widely utilized in the disinfection of drinking water and, more recently, in the disinfection of surfaces and structures. Trihalomethanes (THMs) that react with chlorine and organic materials are suspected carcinogens. THMs, haloacetic acids (HAAs), haloacetonitriles (HANs), and halogenated ketones are the most common disinfection by-products (DBPs). Cancer, abortion, poor birth weight, and congenital impairments are all increased by exposure to these by-products. This study aimed to highlight the ability to use chlorine dioxide as alternative for chlorine to reducing carcinogenic hazardous organic material formation. The study resulted that both the concentration of chlorine and chlorine dioxide is one of the major parameters in hazardous organic material formation.

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