Managed aquifer recharge: study of undisturbed soil column tests on the infiltration and treatment capacity using effluent of wastewater stabilization pond

Recarga gerenciada de aquíferos: estudo em amostras indeformadas de solo sobre a capacidade de infiltração e de tratamento de efluente de lagoa de estabilização

ABSTRACT

Managed Aquifer Recharge (MAR) is a useful tool for the treatment and use of sewage effluent because it complements conventional treatment, recovers the aquifer and minimizes risk of saltwater intrusion. This study aims to investigate technical data to determine the treatment of wastewater stabilization pond effluent using undisturbed soil columns collected from a coastal watershed study area within the BRAMAR (BRAzil Managed Aquifer Recharge) project. The treatment efficiency was monitored by measuring physico-chemical parameters (BOD ₅, COD, DOC, TSS, NH₃ and NO₃) in two columns filled with undisturbed sandy soil in which sewage effluent was infiltrated under unsaturated condition for 72 days with an average input flow of 10 mm h^-1. Results indicated reduction greater than 60% of organic matter, suspended solids and ammoniacal nitrogen. However, high concentrations of nitrate in the outflow were detected originating from nitrification of ammoniacal nitrogen. Moreover, difficulties in relation to soil clogging were observed. Furthermore, this study brought relevant contributions to understanding the influence of the infiltration rate and ability to treat effluent from wastewater stabilization ponds using undisturbed soil columns. Future research should be undertaken to improve the pretreatment methods and the operation of a MAR system in the study area.

Keywords:
Managed aquifer recharge; Infiltration rate; Clogging