Science Target Conference Systems, Ajman 4th International Environment Conference 2016

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Contamination of soil and crops irrigated with recycled domestic wastewater
suhad Almuktar, Suhail Abed, Miklas Scholz

Last modified: 2016-01-04

Abstract


Due to water scarcity in many arid countries, there is considerable interest in recycling wastewater streams such as treated urban wastewater for irrigation in the agricultural sector. The aim of this study is to assess the contamination of soil and the example crop Chilli irrigated by domestic wastewaters treated by different wetland types between September 2013 and September 2014. The objectives were to assess (a) the impact of different treated wastewaters as a function of the wetland type, (b) the volume of treated wastewater available for irrigation, (c) the impact of the environmental conditions, and (d) the impact of different growth media. Ortho-phosphate-phosphorus, ammonia-nitrogen, potassium and manganese concentrations in the irrigation water considerably exceeded the thresholds for irrigation water. High contamination levels of total coliforms, Salmonella spp. and Streptococcus spp. were detected. No mineral contamination was observed in the soils due to irrigation with treated wastewater. Results showed that slight to moderate zinc contamination was detected in some harvested Chillies based on common standards for vegetables. Potassium accumulation in the yield had the highest values followed by zinc. In contrast, the lowest mineral accumulation in the yield was observed for iron. No bacterial contamination was detected for fruits harvested from plants irrigated by wetland outflow water. However, findings indicate that vegetable pots receiving wastewater treated with wetlands can be considered as safe compared to those receiving only preliminary treated wastewater. The project contributes to ecological sanitation understanding by closing the loop in the food and water chain.