The Potential Use of Sewage Sludge from Sheikh Ejleen TP for Agriculture

Abstract

This study aimed to characterize the potential use of sewage sludge from wastewater treatment plant from Sheikh Ejleen for agricultural use. Sludge samples were collected from Sheikh Ejleen Wastewater treatment plant. Air-dried, sieved through 2mm and stored in plastic bags at room temperature. Sludge density, particle size distribution, water holding capacity, void volume, pH, EC, cations and anions contents, Total Kjeldahl Nitrogen (TKN), BOD, COD, Total organic carbon, hydrophobicity, heavy metals content, Influence of sludge on agricultural use were characterized using the standard methods of Analysis. Results showed the bulk density is about 1.18 g/cm3 whereas the real density is 2.12 and void volume is 50%; Particle size distribution showed that the major size of sludge is sand-like size (630-200 µm) and the minor size is silt and clay-like size (200-20 µm); Sludge has an acidic pH reaction with an electric conductivity equal to 2.49 mS cm-1; sludge contained high fraction of TKN 5g/kg whereas the soluble nitrogen is 61.63mg/kg. Na+, K+, Ca2+ and Mg2+ were 28.93, 2.53, 271 and 177 mg/kg respectively whereas PO4, SO4, Cl were 0.434, 18.59 and 0.026 g/kg respectively. Heavy metals content such as Fe, Cu, Pb, Zn and Mn were 125.12, 172.56, 76.88, 218.73 and 157.56 mg/kg respectively. COD and BOD values were 60.99*103 mg and 115mg respectively. The hydrophobicity of sludge is very high, Water Drip Penetration Time (WDPT) is 114.77±18.78 sec with a radius of 0.44±0.08 cm. In the way around, Oil Drip Penetration Time (ODPT) of sludge is 5.05±1.28 sec with a radius of 1.25±0.14 cm. The WDPT/ODPT is very high value 22.73 indicating extreme hydrophobicity. Addition of sludge to soil in the pot experiment had not a significant influence on soil nutrient status, since soil pH, EC, Nitrate levels were not changing. Whereas it significantly increased the corn growth. It appears that 5ton/ha as an addition rate was the optimum among all cases (0ton/ha, 1ton/ha, 10ton/ha). It can be concluded that Application of sludge “biosolids” could be advantageous opportunity for agricultural uses. These encouraging results may enhance the application of sludge in the agricultural sector for improving plant growth and yields.