As arid conditions become more common, customized water treatment systems will be needed
Droughts that have plagued much of the world in recent years have also taken a toll on the quality of available water. Many water systems already have been tested by drought, but experts say exponentially more systems will soon need to prepare for the challenge.
Degradation of water quality is caused by a number of factors, including less dilution, higher water temperatures, and increased salinity. Contaminants vary greatly so it’s essential that water treatment be customized to specific source waters.
During droughts, flow and volume reductions increase salinity by decreasing dilution. Water temperatures may also increase due to longer times in reservoirs and warmer conditions, promoting stratiﬁcation, algae, and toxic blooms of cyanobacteria, and reducing dissolved oxygen.
Local pollution also has a greater effect on water quality during drought due to less dilution. Under drier conditions, geochemistry in catchments can change. One example is sulfide oxidization, which causes severe downstream contamination with major ions, nutrients, and carbon.
Humans often respond to drought by drilling deeper wells or switching water supplies, which may alter arsenic and saline concentrations in well water. More irrigation in response to low precipitation may also increase contaminant levels.
Large Scale Study in California
During an earlier drought in California, some water systems experienced elevated nitrates, arsenic, and uranium levels, yet experts warned of large gaps in their understanding of how droughts affect groundwater.
To fill in the gaps, the United States Geological Survey studied 30 years of groundwater and nitrates data from wells in California’s Central Valley, one of the richest agricultural areas on the world. It is the first study of its size to directly link major groundwater-level declines to decreased groundwater quality. The study suggests groundwater pumping during drought can pull shallow, polluted groundwater down to aquifer depths that are used for drinking-water systems.
Responding to Water-Quality Issues
Water systems contend with diverse contaminants in different proportions. Common water contaminants include:
- Naturally occurring arsenic, heavy metals, and radiological contaminants
- Salt, typically found deeper in aquifers or in depleted coastal aquifers
- Nitrate, phosphorus, and arsenic in agricultural areas
- Bacteria from improperly maintained septic systems in rural areas and discharges from inadequate treatment facilities
Arsenic: Several technologies can be used to remove arsenic depending on factors specific to the source water. Fluence has optimized coagulation filtration, oxidation filtration, adsorption with specific media, ion exchange, and membrane filtration to meet the varying needs of each location.
Desalination: Fluence’s modular NIROBOX™ is a versatile reverse osmosis solution that can be customized to treat seawater, brackish water, or freshwater.
Wastewater Treatment and Reuse: Fluence’s Aspiral™ modular wastewater treatment units excel at nutrient removal with low energy requirements. Water from Aspiral™ plants, which use membrane-aerated biofilm reactor (MABR) technology, routinely exceeds the highest wastewater treatment standards in the world for nonpotable water reuse.
Aspiral™ units help during drought in a number of ways. High-quality water is suitable for agricultural irrigation and other nonpotable applications, which reduces withdrawals from aquifers. The treated water can be discharged without contaminating water resources. As droughts threaten water quality and availability throughout the world, it makes sense to reuse every drop of water possible.
Both NIROBOX™ and Aspiral™ are packaged in weatherized steel containers that can be transported nearly anywhere in the world and installed in record time with minimal construction. Nonspecialized personnel can monitor and operate the plants remotely.
Contact our experts to determine the most effective solutions that will ensure the quality of your source water.