Accumulated Organic Matter Degradation and the Function of Porous Media during Enhanced Sewer Self-purification

Abstract

This study aims to clarify the function of different porous media layers during accumulated organic matter degradation with enhanced sewer self-purification by porous sponge media. To do so, intermittent flow and low continuous flow were applied to channels containing sponge media while maintaining similar volumetric flow rates per channel. Accumulated organic matter, in the form of margarine, was placed underneath the sponge media. Aerobic activity related to organic matter degradation was monitored for 32 days followed by test sponge oxygen consumption and biomass density evaluation. Porous sponge media of different pore cell radii and thicknesses were tested under the described conditions. Findings for intermittent flow showed that although the top layers did not have direct contact to accumulated organic matter, they contributed 33–70% to the total aerobic activity related to organic matter degradation. A lower contribution of 12–42% was found for the top layers for channels subjected to low continuous flow. For all channels, higher biomass density was found for the bottom layer directly in contact with accumulated organic matter. Findings show that while the bottom layer may have higher contribution to organic matter degradation, the upper media layer contributes significantly to aerobic activity during enhanced sewer self-purification.

Keywords

• sewer self-purification
• porous media
• wastewater treatment