A study of columns to reduce mineral and biological pollutants during recharge operation by treated municipal wastewater.

One of the most important methods for reusing treated wastewater is soil aquifer treatment (SAT). For simulation of SAT pounds, three columns of 30 cm in diameter and 250 cm in height were filled with sandy loam soil and used to assess the removal of chemical and biochemical oxygen demands (COD and BOD), nitrogen, phosphate, total dissolved solid, total coliform, and fecal coliform from treated wastewater. The soil surfaces of columns were covered by different materials; one by geotextile, another by coarse structural debris, and the third one remained bare. These columns were saturated by treated wastewater from Mahdasht–Karaj treatment plant. All of the experiments were conducted under permanent saturated soil condition. The removal percentages of geotextile soil column were 84.7, 77, 67.7, 99.5, 99.7, and 79.9 for BOD, COD, TSS, coliform, fecal coliform, and phosphate, respectively, and low efficiency for nitrate removal in all columns. Also it was observed that more waterlogging time leads to a decrease in pollutant removal. Using geotextile and structural debris as soil surface covers will lead to a reduction in pollutants transfer and help in stabilizing the soil system as a filter. [ABSTRACT FROM PUBLISHER]