258 Drilling Shaft Water Treatment
The Water Treatment Facility needed to remove the sludge from the flooded water treatment shafts. They installed multiple pumps and Geotextile bags in order to collect and pump out the water in each flooded shaft. WaterSolve was tasked to evaluate the sites for chemical conditioning programs and subsequent application of Geotextile containers for containment and dewatering of residuals.
DOWNLOAD PDF Applications & ProductsGeotextile Tube Containers, DewateringServicesTurnkey Project ManagementIndustryEnvironmental clean upLocationWisconsin, USA
Geotextile Tube Container on a Barge
A 30’x50’ Geotextile container on a barge in the river is pumped, periodically, to a height of 6’ to dewater and consolidate drilling residuals from an under-river pipeline project.
Under‐river Pipeline Project
View looking down upon the crew assembling the under-river pipeline
Polymer and Mixing
A key element in the release of water from drilling residuals is proper polymer mixing and injection to provide good chemical conditioning. Our polymer feed system provided accurate dosing of chemicals to effectively contain residuals and to meet local TSS discharge limits.
Overview
An environmental construction company and general contractor specializing in the installation of below ground pipelines and horizontal mining, were awarded the task of constructing a 60-mile potable water pipeline (48” diameter) from the city’s Water Treatment Facility. The construction company was to provide 35’ diameter down-shafts on the north and south banks of the one river and east and west shores of another river for subsequent installation of the pipeline below the two rivers. One to two 4” submersible pumps (500 gpm) were used to pump-out water from each flooded shaft. Shafts were flooded on purpose to suppress explosive blasts as well as the water that enters due to occurring through fissures in the rock of the down-shafts during excavation. A 40 mg/L total suspended solids (TSS) permit limit was issued for this project by the Wisconsin DNR, limiting the liquid residuals to be discharged to any surface receiving systems. Initial residuals containment technologies included 15-cy filter bags, construction-grade filter fabric installed throughout a settling bed of gravel, and other containment options (e.g., filter boxes). Unable to meet the 40 mg/L TSS discharge limit, an alternative method for containment and dewatering was sought by the project manager, which not only reduced the costs associated with residuals processing but required less resources to operate. WaterSolve was tasked to evaluate the sites for chemical conditioning programs and subsequent application of Geotextile containers for containment and dewatering of residuals.
The Solution
WaterSolve, LLC identified a dual polymer chemical conditioning program and recommended Geotextile Containment and Dewatering Technology, as a cost effective and efficient method for handling residuals in the shortest amount of processing time. Geotextile containers, which are manufactured from high strength polypropylene fabric, are designed to allow effluent to escape, but capture the flocculated drilling residuals. As a result of WaterSolve’s site specific chemical conditioning program, filtrate from Geotextile container technology met state discharge permit limits and allowed are designed to allow effluent water to escape through the pores of the fabric while retaining the solids. A bermed lay-down area with clean rock at each site was constructed to contain the Geotextile container. A dewatering performance trial was performed to determine the most effective chemical conditions program. Dewatering polymers were evaluated based on water release rate, water clarity, and flocculant appearance.
THE RESULT
With this technology, they were able to contain and dewater a full year of residuals production into one Geotextile container at each site and
minimize the excavation and hauling costs. WaterSolve completed installation of the Geotextile tube containers, temporary piping, and polymer
make-down unit in April 2006. Liquid residuals (500,000 gallons) at 0.5-1.0% solids were chemically conditioned with Solve 216C and pumped
daily into the Geotextile bags. As a result of WaterSolve’s site specific chemical conditioning program, filtrate from Geotextile container technology
met state discharge permit limits and allowed for continuous operation of all three drilling sites for the term of this project.
