Nitrogen removal from septic tank effluent using sand filtration and sulfur/limestone denitrification

The control of nitrogen from on-site effluents has been identified as an important measure to minimize groundwater pollution by nitrates. A study was conducted to remove nitrogen from a septic tank effluent. The primary objectives of the study were: (1) to investigate the applicability of a sand filter system for nitrification of STE (septic tank effluent) and sulfur/limestone autotrophic denitrification (SLAD) layer to treat the nitrified effluent as a single pass system; and (2) to determine an optimum ratio of sulfur to limestone in the SLAD layer.; Column based studies were conducted to achieve the objectives. Studies include conducting experiments and plotting nitrogen, COD, alkalinity, and sulfate profiles along the system. The systems were dosed intermittently with 6 h resting period between application at uniform rates of 4 and 8.1 cm/d of STE for 160 and 40 days respectively (for a total of 200 consecutive study days).; Studies to determine a proper ratio of sulfur limestone mixture and applicability in real life, three ratios (mass to mass) 1/1, 2/1, and 3/1 of sulfur and limestone were examined. (Abstract shortened by UMI.)...