Reoccurring extreme floods and droughts due to climate change are causing water storage issues.
In response to this, aquifer storage technology is being used to supply water in the United States, the Netherlands, and Australia.
In South Korea, it rains intensively in the summer, causing increasing difficulties in water supply in rural areas and island areas other than urban areas.
In this situation, aquifer storage technology is attracting attention as a way to store and supply water stably.
Dr Seongpil Jeong and Kyungjin Cho of the Center for Water Cycle Research at the Korea Institute of Science and Technology (KIST) have developed an aquifer storage technique that could improve the potential for stable water storage.
Stimulating the recovery process of aquifer storage
The injection of surface water into aquifers without proper treatment can be limited by pore-clogging caused by microorganisms that feed on organic matter, such as assimilable organic carbon, present in the injected water.
The KIST research team had previously shown that microorganisms can reduce assimilable organic carbon in artificial raw water under simulated aquifer storage conditions.
In this study, real river water rather than artificial water was used to simulate the periodic injection and recovery process of aquifer storage.
The experiment lasted for about 13 months. River water was injected into a sandy layer in the ground at two-week intervals and withdrawn again two weeks later to observe changes in organic matter and microorganisms over the course of the experiment.
The experiment showed that despite seasonal changes in river water, organic matter concentrations in soil organic matter and stored water remained stable.
This suggests that a simple physical sedimentation process without chemical treatment maintained stable water quality for a year without pore clogging.
Understanding why water quality remains stable in these systems
To understand why water quality remains stable in aquifer storage systems, the team investigated changes in the microbiome.
They found that the microbiome, which can feed on organic matter present in real river water, changes seasonally.
This suggests that the microbes in the aquifer storage system reduced organic matter, preventing pore clogging and contributing to stable water quality.
The experimental techniques used in this study can be used to test domestic aquifer storage sites and propose pre-treatment processes for influent conditions.
The future of stable storage systems
It is believed that continued analysis of organic matter and microorganisms will be necessary for the stable operation of aquifer storage systems in the future.
In addition, a water quality assessment of the recovered water and appropriate pre-treatment processes are needed to ensure the system’s stability.
“This research contributes to the stable operation of aquifer storage technology, which is being utilised as a large-scale water storage technology to address the problem of water supply imbalance,” the researchers explained.
“The study of long-term organic matter and microbiome changes in a pilot-scale aquifer simulation system is the first of its kind globally and has potential for future expansion.”
