Economic Feasibility Study on the Use of Certain Amendments in the Bioremediation of Sewaged Soil

Abstract

Cairo is now served by six large wastewater treatments works which produce significant quantities of sewage water. The preferred option is to use this in agriculture, particularly in reclaimed desert land which is inherently deficient in organic matter, nutrients and trace elements. The aim of this study was to assess economic feasibility of a novel biotechnology for remediation of sewaged soils on a long term basis. A field study was carried out at Abu-Rawash Sewage Farm where the soil has been irrigated with water sewage for 32 years and the site provides a possible model of the potential long-term effects of heavy metals and other pollutants on crops in the contaminated sewaged soils in Egypt. The high contaminated sewaged soil was bioremediated for 60 days with sole or combined remediative amendments in different treatments including uncultivated control, cultivated control, inoculation with AM, inoculation with a mixture of Thiobacillus thiooxidans & Thiobacillus ferrooxidans, treated with probentonite or treated with combined mixture of all the aforementioned remediative amendments before sowing. Canola was sowing in winter season as a hyperacumulator plants after remediative periods. Save grains, seeds and oil yield were determined after canola and maize harvest. The costs for land preparation, bioremediation materials and processing, cultivation operation and requirements for growing and harvesting canola and maize (summer season) were calculated. Three scenarios have been conducted i.e. rent the land and buying the variable and fixed production factor, without yield useful, the second scenario similar to the first one but take a yield from maize in the first year, and the third scenario is rent all production factors with sold a maize yield in the first year. The final results indicate that the internal rate of return for the first, second and third scenarios were 21.1%, and 44.2%, and 38.3% respectively. Accordingly, the 2nd scenario was the best one under our experimental conditions after bioremediation of contaminated soils, and may also be applied by the farmers whom do not have a large capital for the purchase the fixed assets.