New research on aquifer recharge for water reuse

Two reports have recently been published about research on the use of aquifer recharge as a method of wastewater reuse.

The first, Quantifying the effect of Managed Aquifer Recharge on the microbiological human health risks of irrigating crops with recycled water published in Agricultural Water Management (99: 93-102) reports a study conducted under the EU’s Reclaim Water Project.

In Managed Aquifer Recharge (MAR), recycled water is added to aquifers either by injection or infiltration, to ensure a constant supply of groundwater that helps meet irrigation demands. Often MAR can improve the quality of the recovered water by filtering out potentially harmful microbes; however, few studies have quantified the human health risk from using reclaimed water for irrigation.

A World Health Organization (WHO) panel has requested that guidelines for water reuse be made into a single ‘Safe Water’ framework, which uses a Quantitative Microbial Risk Assessment. Four study sites were selected which used recycled water for MAR: Bolivar (Australia), Nardò (Italy), Sabadell (Spain) and Shafdan (Israel).

The researchers compared MAR’s effects on microbe levels in recycled water with the effects of a wide range of different water treatment methods including chlorination, UV treatment and sand filtration, which were also present at the different sites studied. MAR resulted in the greatest human health risk reduction.

The second report, published by the news agency Maxims News Network, is an interview with Professor Sadahiko Itoh of Kyoto University discussing his current research project, New Water Reuse System using Urban Aquifer with Advanced Risk Management.

The research project comes under the Japanese CREST water technology research funding grants, which in 2011 made awards to six Japanese scientific teams working on water- related technologies. It is being carried out by Kyoto University and the National Institute of Public Health.

The primary goal is to establish a new water reuse system using aquifer layers for intermediate treatment and water pathways linking wastewater treatment plants (WWTPs) to water treatment plants (WTPs). After treatment to an appropriate level, urban wastewater is converted into a source of drinking water in the subsurface environment.

Effluent from WWTPs will be treated through the soil aquifer by biodegradation and sorption, a process known as Soil Aquifer Treatment. Improving water quality, through biodegradation and sorption in soil, could perhaps help rethink the current water treatment processes, says Itoh.

He believes his system minimizes costs and energy consumption while delivering a final product with acceptable quality levels.

In this project, Itoh is focussing on the underground infiltration process and studying the:

  • Acceptable wastewater quality levels for underground infiltration process
  • Conversion process of water quality in the subsurface environment
  • Sustainability of this water reuse system
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