Reactive Barriers for Renaturalization of Reclaimed Water during Soil Aquifer Treatment

Abstract

Managed aquifer recharge (MAR) is known to increase available water quantity and to improve water quality. However, its implementation is hindered by the concern of polluting aquifers, which might lead to onerous treatment and regulatory requirements for the source water. These requirements might make MAR unsustainable both economically and energetically. To address these concerns, we tested reactive barriers laid at the bottom of infiltration basins to enhance water quality improvement during soil passage. The goal of the barriers was to (1) provide a range of sorption sites to favor the retention of chemical contaminants and pathogens; (2) favor the development of a sequence of redox states to promote the degradation of the most recalcitrant chemical contaminants; and (3) promote the growth of plants both to reduce clogging, and to supply organic carbon and sorption sites. We summarized our experience to show that the barriers did enhance the removal of organic pollutants of concern (e.g., pharmaceuticals and personal care products). However, the barriers did not increase the removal of pathogens beyond traditional MAR systems. We reviewed the literature to suggest improvements on the design of the system to improve pathogen attenuation and to address antibiotic resistance gene transfer.

Nitrogen Removal Capacity of Microbial Communities Developing in Compost- and Woodchip-Based Multipurpose Reactive Barriers for Aquifer Recharge With Wastewater

“…This offers a range of redox conditions and adds sorption sites that facilitate biodegradation and retard the transport of pollutants through the system ( Valhondo et al, 2018 ), but the efficiency and capacity to remove environmentally harmful pollutants are uncertain and will depend on the type of barrier, pollutant ( Modrzyński et al, 2021 ), and the operation of the system. The addition of reactive barriers has shown promising results for the removal of organic micropollutants and for reducing the number of pathogens in the treated water ( Schaffer et al, 2015 ; Valhondo et al, 2020a ; Modrzyński et al, 2021 ). With respect to nitrogen (N) removal, reactive barriers can also support denitrification for the removal of nitrate ions ( Beganskas et al, 2018 ; Grau-Martínez et al, 2018 ).…”

Managed Aquifer Recharge for Water Resilience

“…Water quality improvement is also an objective of soil aquifer treatment systems that intermittently infiltrate recycled water. Valhondo et al [7] tested the use of several types of organic-rich reactive layers placed at the bottom of infiltration basins to enhance water quality improvement during soil passage. Field tests were performed at two sites in Spain.…”

Regulations and guidelines on water quality requirements for Managed Aquifer Recharge. International comparison

“…An important group of contaminants to consider are the emergent pollutants, which pose a major concern in the reuse of reclaimed water (WHO 2003;Valhondo et al 2020). The water quality standards from the USA, Italy, México, The Netherlands, Shafdan and Torreele take into account these sorts of pollutants.…”

“…To date, only a small number of countries have stepped up with policies concerning environmental and health protection in MAR (Dillon et al 2009). This situation, which often implies a lack of clear rules and water quality standards, can result in a public misperception of MAR or in implementations which have negative impacts on human health and ecosystems (Valhondo et al 2020;WHO 2003). Such concern has been recently tangible in Europe, where some experts presented claims and recommendations to the first draft of the regulation on water reuse (JRC 2017).…”