Water repellency reduction using soil heating in infiltration ponds of a wastewater soil aquifer treatment (SAT)

Abstract

Reuse of treated wastewater (TWW) for irrigation in agriculture is a common alternative water source in arid regions suffering from fresh water (FW) shortage. Soil aquifer treatment (SAT) is frequently used for advanced TWW purification. Infiltration rates of water through the soil can decrease as a consequence of organic matter (OM) accumulation and the consequent induction of water repellency. In this research, soil heating to high temperatures was examined for its efficiency in OM content reduction and increased infiltration. In a laboratory experiment conducted using a hand burner and a combustion oven, water repellency was found to be reduced following increased heating temperature or heating duration, directly resulting in reduction of OM level. Chemical analysis of OM extracted from the heat treated soils revealed reduction in hydrophobic substances as a consequence of increased temperatures by soil heating and heating duration. In model ponds built to simulate large infiltration basins, OM content was reduced as a result of intensive and moderate soil heating in comparison to the untreated pond. However, no reduction in water repellency and only slight changes in infiltration rate were found as a consequence of soil heating. The differences in results obtained in the laboratory and the field experiments were probably related to the fact that the soil in the field experiment has been continuously reloaded with TWW containing OM.

Role of Soil Biofilms in Clogging and Fate of Pharmaceuticals: A Laboratory-Scale Column Experiment

“…The net effect is that clogging has the largest impact, in relative terms, in absence of SOM. This finding is in accordance with field results of Nadav et al, 78 where heating treatment of an infiltration pond operated with reclaimed water, to reduce the SOM of the facility, did not result in an improvement of the infiltration capacity. Moreover, Valhondo et al 79 noticed that the addition of organic layers (compost) in pilot plants for artificial recharge with WWTPs secondary effluent prevented clogging.…”