Abstract:
The population growth and rapid urbanization, as well as climate change and the indiscriminate use of freshwater has lead to the era of water resources dwindling and water scarcity problem worldwide. Therefore, most researchers have shown great interest in treatment, recycling and reuse of wastewater particularly in agricultural activities. In general, wastewater contains beneficial features such as nutrients that is required for plants growth and development. The present study was conducted at NUST H-12 to evaluate performance efficiency of membrane bioreactor by cultivating green vegetables. Selected vegetables were Lettuce and Spinach. The studied water quality parameters were; Chemical oxygen demand (COD), Total suspended solids (TSS), Total dissolved solids (TDS), Electric conductivity (EC), pH, Total phosphates (TP), Dissolved oxygen (DO), Temperature, Total coliforms and Fecal coliforms. The system proposed was found to have produced satisfactory results where the average removal efficiencies of COD, TSS, and TP were 87, 74.3 and 75% respectively. HPC in both lettuce and spinach samples were exceeding the quality standard of 103 CFU/g provided by International Commission on Microbiological Specifications for Food (ICMSF) and 2.3 log CFU/g by WHO. Salmonella count in lettuce and spinach grown in wastewater was 6.86 and 5.88 log CFU/g whereas the MBR treated wastewater vegetables had Salmonella count 2.20 and 2.18 log CFU/g. Predominant species of parasite were A. lumbricoides, T.trichiura and Hookworm. A. lumbricoides was the most dominant specie. Acinetobacter johnsonii, Pseudomonas monteilii, Pseudomonas putida, Raoultella ornithinolytica, Aeromonas hydrophilla and Aeromonas veronii were the predominant genera of bacteria in wastewater and MBR treated wastewater. Principal species identified in spinach and lettuce were Escherichia coli, Shigella flexneri and Salmonella enterica.
