Water Quality Improvements in Soil Aquifer Treatment (SAT) Simulated Soil Columns

Artificial recharge of Aquifers with treated wastewater is one of the most promising techniques for its reuse. Usually laboratory and pilot scale field studies are conducted for investigating the feasibility of wastewater recharge for any aquifer. The addition of sand to the local soil can improve the performance of the Soil Aquifer Treatment (SAT) process. Thus, a laboratory study was conducted to investigate the effect of sand amendment with local Sandy Clay Loam (SCL) texture soil collected from Anna University Sewage Treatment Plant (STP), Chennai, India. Four 35 cm long PVC soil columns were fabricated and were filled with 5 % (R5), 10 % (R10), 15 % (R15) and 20 % (R20) sand amended soil. The experiments were run simultaneously for a period of ten cycles with 3 days wet/4 days dry cycles. Water samples were collected at the outlet of the columns and analysed for TDS, ammonia, nitrite and nitrates. The removal of ammonia was through nitrification process which was found to be a dominant removal mechanism of nitrogen. When reduction performance achieved with different sand amendment columns were compared, it could be seen that R10 column yielded with least nitrate value of 0.69 and 1.57 mg/l after 1st and 3rd wetting day.