Study of Sewage Sludge Use for Cultivation of some Plants and its Effects on some Soil Properties at Al Ahsa

Abstract

Wastewater treatment plants produce a large amount of sludge, which negatively affects our environment. The agricultural application of sludge is an environmentally friendly disposal option. The current study investigated the use of sewage sludge in the fertilisation of arid land in Al Ahsa, KSA, to reduce the need for importing fertilisers and increase plant productivity. Sewage sludge was used as an organic fertiliser in the cultivation of cucumber (Cucumis sativa) and lettuce (Lactuca sativa) through its scalable addition to sandy soil at rates of 0 (control soil), 5, 15 and 45% in a pot experiment under greenhouse conditions. Chemical and microbiological analysis was carried out using a UV spectrophotometer, flame photometer and atomic absorption spectrum. The results indicated that the application of sewage sludge significantly altered soil properties. The total dissolved salts (TDS), soluble anions (Cl, HCO 3 , NO 3 and SO 4), soluble cations (Na, K, Ca and Mg), nutrients (TKN, TP) and trace metals (Fe, Mn, Cu, Zn and Cr) increased in the sandy soil with the increasing sludge application rates. For example, the average TDS in the soil increased significantly (p<0.01) from 0.667 gm/l for the control to 1.73, 2.33 and 3.04 gm/l in soil mixed with sludge at 5, 15 and 45 %, respectively. The application of sewage sludge improved soil properties and increased organic matter from 1.72% in the control soil to 9.36% in the soil mixed with 45% sludge. In addition, the application of sewage sludge increased the growth yield of lettuce and cucumber plants. In conclusion, the current study revealed that using sewage sludge as organic manure at a low application rate of 5% can improve the soil's physical and chemical properties, provide plants with the required nutrients, and increase growth and yield.

An Assessment of Irrigation Water Quality with Respect to the Reuse of Treated Wastewater in Al-Ahsa Oasis, Saudi Arabia

“…Phosphate and nitrate were positively correlated (p < 0.01) with correlation coefficients of r = 0.30. The current study revealed relatively higher values of phosphate and nitrate measured in treated wastewater used in irrigation, which could improve the soil fertility of semiarid land [20]. Nitrate and ammonium had a weak, but significant, negative correlation (r = 0.28, p < 0.01).…”

“…Hence, the main sources of irrigation water in Al-Ahsa Oasis are currently groundwater wells mixed with both treated wastewater and partially agricultural drainage water. Approximately 200,000 m 3 /day of treated wastewater used in irrigation derives from main sewage treatment plants (STPs) in Al-Ahsa, namely Hofuf STP, Umran STP, Oyun STP, and Aramco STP [20]. These sewage treatment plants use both primary, secondary, and tertiary treatment processes along with the use of an aerobic activated sludge method.…”

“…High concentrations of phosphate and nitrate in treated wastewater can cause eutrophication problems of the receiving water body. However, the controlled use of treated water in irrigation improves soil and plant health with nutrients and consequently increases agricultural production, especially in arid/semiarid areas [6,20,21].…”

“…These include the provision of an alternative option to increase the available water resources, meeting water demand, addressing water shortages, conserving freshwater, coping with dried climatic conditions, and resolving the untreated sewage water indiscriminate disposal issues [6,18,19]. Moreover, the reuse of treated wastewater in irrigation leads to enhancing the soil and plants with organic matter and nutrients, reducing the use of soil chemical fertilizers, increasing agricultural production along with decreasing costs, and adapting to climate change [6,20,21].…”

Characterization of Waste Activated Sludge for Sustainable Disposal in Jamaica

“…Land application of the sludge is a traditional disposal option because it offers the possibility of recycling plant nutrients, providing organic material, improving soil fertilit y along with physical properties and enhancing crop yield [6,7]. The organic fraction in organic amendments can enhance significantly soil, water infiltration, microbial activity, structure, and water holding capacity and it can reduce soil compaction and erosion [8]. Chemical properties such as electrical conductivity (EC), organic carbon, and soil pH may also be improved by organic amendments application [9].…”