Agricultural Wastewater Treatment Using Activated Carbon Produced from Groundnut Husk and Abizia Saman Pod

Population explosion, haphazard rapid urbanization, agricultural, industrial and technological expansion, energy utilization has rendered many waters unwholesome and hazardous to man and other living resources. Fertilizer application is one of the major activities carried out on farms to improve crop yield, and one of the major fertilizers used is the NPK fertilizer but such activity also causes pollution to the water bodies through runoff or discharge from such agricultural lands. Recently, the removal of N and P from aqueous solutions via adsorption has attracted much attention. Column study was carried out on groundnut husk and albizia saman pods as activated carbon in the removal of N, P and K from agricultural wastewater considering factors such as flow rate (20, 30 and 40 ml/min) and bed height of the column (6, 9 and 12 cm). The physico-chemical characteristics of the adsorbent such as; specific surface area, pH, ash content, organic content, organic matter, bulk density, nitrogen and moisture content were determined. Result from the adsorption experiment showed that the higher the bed height the better the performance of the column. Bed height of 12cm at constant flow rate of 20 ml/min. was observed to give the best result for the two adsorbents. At the bed height of 12 cm, the initial concentration of N, P and K (2.58, 1.47 and 3.28 mg/L) were reduced to 0.02, 0.01 and 0.03 mg/L respectively for the first 10 minutes using groundnut husk activated carbon (GHAC). Also, at the bed height of 12 cm, the concentration of N, P and K were reduced to 0.01, 0.01 and 0.02 mg/L respectively at the first 10 minutes using albizia saman pod activated carbon (ASPAC). However, as the treatment time increases, the performance of the adsorbent was observed to decrease for both adsorbents. The result from the experiment also showed that the flow rate of 20 ml/min at constant bed height of 9 cm gave the best performance. At the flow rate of 20 ml/min, the concentration of N, P and K were reduced to 0.06, 0.05 and 0.11 mg/L respectively using ASPAC while the concentrations of N, P and K at the same flow rate were reduced to 0.07, 0.05 and 0.10 respectively using GHAC. This study showed that activated carbon prepared from both ASPAC and GHAC are suitable for the adsorption of N, P and K and as such could be used as a cost effective adsorbent in the treatment of agricultural wastewater.