Abstract
The potential health risk related to wastewater reuse in agriculture remains a major environmental concern; although chlorine is predominantly used to treat wastewater, it leaves behind harmful disinfection by-products. Thus, in this study, a new secondary disinfectant Huwa-San (HS) has been used to reduce the harmful components in wastewater treatment plants. The effluent quality of four wastewater treatment plants and their transport lines in Riyadh, Saudi Arabia, were monitored for 8 months. The description of plants, effluent quality data, and their conformity to the standards are presented. The outcomes of this investigation proved that the mean values of disinfection by HS was more effective than chlorine in decreasing turbidity, ammonia, andE. coliby 2.3%, 20% and 100% in the plants and 97%, 25% and 100% in the transport lines (TL), respectively, while chlorination was more effective than HS in minimizing nitrate concentration and the sodium adsorption ratio (SAR), by 6% and 6% in the plants and in the TL, by 1% and 11%, respectively. The mean values of SAR, EC, and pH under both disinfectants were within water quality Saudi Standard. A monitoring survey at the WWTPs revealed that HS treatment met most of the quality requirements for unrestricted irrigation, whereas chlorine treatment did not achieve most of the quality requirements for restricted irrigation.