A Multispecies Growth and Yield Performance Comparison of Vegetables Cultivated Under Hydroponics Using Sewage Wastewater

Abstract

Reusing sewage wastewater for vegetable cultivation is becoming a solution to sustainable water utilization, particularly in water-scarce regions. Using two types of sewage wastewater, Biologically Treated Water (BTW) and Chlorine Disinfected Water (CDW), and tap water, this study aimed at making a comparison of and understanding the yield performance and chlorophyll content in three vegetables, Phaseolus vulgaris (common beans), Brassica rapa var. perviridis (komatsuna), and Solanum lycopersicum (tomato), grown under hydroponics. The experiment was carried out in the hydroponics greenhouse within the Yokohama Wastewater Reclamation Center, between May 2023 and August 2023. We used a Nutrient Film Technique (NFT) hydroponic system supplied with BTW, CDW, and tap water. The three water types served as our treatments. The plants were grown to maturity at a controlled water temperature. In comparing vegetable yield, an ANOVA test demonstrated significant differences among the treatments for common beans, komatsuna, and tomatoes. The Post hoc test showed significantly higher chlorophyll content for common beans and tomatoes grown in tap water, compared to BTW and CDW. Regarding yield, common beans performed best in the tap water hydroponic system, while tomato and komatsuna performed best in the BTW and CDW hydroponic systems. Results indicate a vegetable differential preference for the three water types used. These three vegetables can thus be cultivated concurrently. Research on the safety of vegetables grown in sewage wastewater and the economic feasibility of using treated sewage wastewater for vegetable production is urged before upscaling this technology.