Photo By Carol Coleman | The Relief Well Sustainment Deployable Resilient Installation water Purification and...... read more read more
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VICKSBURG, Miss. - A multi-agency team of researchers and specialists from the U.S. Army Engineer Research and Development Center (ERDC), the U.S. Army Corps of Engineers (USACE) Vicksburg District, the U.S. Environmental Protection Agency and industry collaborator WaterStep have partnered to design and test a new approach to clean and maintain relief wells from biofilm buildup. The new technology is called the Relief Well Sustainment (RWS) Deployable Resilient Installation water Purification and treatment System (DRIPS) mobile trailer.
Levee systems are part of the nation’s landscape and an important aspect of the USACE Flood Risk Management Program. All levees are subject to seepage that may result in excessive pressure buildup beneath the surface, leading to structure failure and safety concerns. For more than 80 years, the Corps of Engineers has used a system of relief wells to relieve excess pressures in levees, dams and other hydraulic structures.
Tens of thousands of relief wells are located across the United States. Over time, they can become encrusted with corrosion and biofilms, reducing their effectiveness and putting the very structures they protect at risk of failure. However, care and maintenance of the wells is costly, and in some cases, poses potential safety risks.
Current treatments using oxalic acid to alleviate hydrostatic pressures can be harsh and expensive, and the USACE spends millions of dollars each year on maintenance. The wells are treated every 3-5 years, but there is an ultimate goal of reducing that time.
The RWS DRIPS mobile treatment trailer was designed to decontaminate relief well infrastructure at dams and levees and addresses biofilm growth within the wells while mitigating the high costs and safety risks.
“Our system uses the same standard operating procedure to pull up roughly 1,000 gallons of water out of the relief well, and then we infuse bleach rather than oxalic acid into each of the wells for treatment,” said Dr. Clint Smith, a natural resources specialist and research biologist with the ERDC’s Geospatial Research Laboratory.
Smith designed the new relief well biofouling treatment process for dams and levees by reimagining the Water On Wheels cart — a system typically used for federal emergency, post-natural disaster response by WaterStep that provides high-tier product water to affected communities’ non-potable and potable water supply. The system functions as a more cost-efficient and targeted alternative by allowing the use of a portable chlorine generator. It electrochemically converts sodium chloride to sodium hypochlorite, in a controlled and monitored manner, allowing for the use of either chlorine gas or chlorine gas dissolved in water.
“The treatment process is similar in that we treat one day, then we cap the well, and come back with an operational team the second day and push the water out through air pressure,” said Smith. “Essentially, all the treated material and biofilm breaks up overnight and gets pushed out of the well, allowing that pressure to be relieved, and then the well is considered treated.”
The system was field tested at Grenada Lake Dam in Grenada, Mississippi, with the DRIPS trailer added to testing at levees along the Mississippi River in Magna Vista, Mississippi. Initial testing showed that the new method reduces microbial growth just as effectively as current methods with reduced costs. When compared against oxalic acid, the wells treated with the high-strength, gas-infused chlorination system reported no detected level of growth and adequately relieved the pressure on the relief wells to allow proper water-flow and usage.
“We’re evaluating the design and how we can make the process better,” said Smith. “Each time we've come out to a site, we've improved the process. Our goal is to effectively treat the wells, efficiently improving the standard operating procedure for both the cost of the engineers being out on site and the amount of wells they can possibly treat within a day, as well as evaluating the cost difference between using salt versus buying bags of oxalic acid.”
With the DRIPS trailer attached at Magna Vista, the team implemented a treatment plan for each individual relief well, utilizing varying concentrations and liquid volumes of the high-strength gas-infused chlorination, or bleach, generated for water treatment.
“We’re doing an analysis of that process to measure how much bleach each well needs in order to be considered treated, and we’re doing the comparison between the oxalic acid and the gas infused bleach process,” said Smith. “We've done some initial investigation, and the percentage is much lower for the cost of salt per pound than the oxalic acid, so there is a cost savings over time.”
Several USACE districts are interested in the technology with talks for more field demonstrations in fiscal year 2025.
“Other districts have reached out to us with interest in the treatment, so we've started developing the cost analysis for them,” said Smith. “Each district operates differently depending on their area of responsibility, so we're providing them that analysis.”
Currently, ERDC has one RWS DRIPS mobile treatment trailer on hand, with the unit used at the Magna Vista test site already transferred to the Vicksburg District for further use.
| Date Taken: | 11.25.2024 |
| Date Posted: | 11.25.2024 13:42 |
| Story ID: | 486082 |
| Location: | VICKSBURG, MISSISSIPPI, US |
| Web Views: | 103 |
| Downloads: | 0 |
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