Rice Straw as a Sustainable Treatment Medium for Grey Wastewater: Case Study in Damietta, Egypt

The current study aimed to assess the feasibility of using agricultural waste (rice straw), along-with sand and gravel (treatment system A), to treat grey wastewater in comparison to other treatment systems (B, C, and D), which contain diverse treatment media, like sand and gravel only, activated carbon beside sand and gravel, and fired clay along-with sand and gravel, respectively, as wastewater filters. Grey wastewater samples were collected from three selected homes in Damietta Governorate, Egypt, and treated using the four different treatment systems. According to the standard methods of analyses, some physico-chemical characteristics of the grey wastewater, including: temperature, pH, turbidity, TDS, EC, NH 3 , O.P, BOD, and COD, were examined before and after the treatment. Moreover, microbiological characteristics such as TBC, TC, and E. coli were also inspected. The results showed that the physico-chemical characteristics of the treated grey wastewater via the applied treatment systems complied with the ESL for effluents discharged to the sewer systems. The outcomes revealed that the cost-effective treatment system (A) was the best in removing some physico-chemical characteristics compared to the other applied systems, especially in removing BOD, TDS, and EC with mean percent removal of 77.54±4.21%, 47.74±17.62%, and 45.84±16.96%, respectively. Simultaneously, this system achieved good elimination of Turbidity, COD, NH 3 , and OP with mean removal rates of 86.14±10.49%, 84.76±1.77%, 74.5±16.11%, and 71.77±8.12%, successively. Moreover, it has substantially removed some microbiological characteristics from the grey wastewater without disinfection and attained removal rates of 94.42% and 69.33% for E. coli and TBC, respectively.