New Focus: Environmental Impact Reduction of Proper Slurry Waste Management-Paper

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The paper presents two construction projects demonstrating how onsite slurry-waste treatment can reduce costs, waste, trucking, and environmental impacts.<br /><br />For jet grouting in Ottawa, limited site space and high spoil volumes made traditional vacuum-truck removal impractical. A system of shakers, tanks, centrifuges, and flocculant processed the backflow into reusable water and dry, stackable solids. Treatment reduced waste by 1,016 tonnes (47%) and estimated project costs by C$122,416 (23%) compared with vacuum-truck disposal. It also avoided 240 truckloads, saved about 14,453 litres of fuel, and reduced greenhouse-gas emissions by an estimated 38,814 kg of CO₂. Operations continued without treatment-related downtime, and the recovered water and solids met local disposal requirements.<br /><br />For slurry-wall construction in Vancouver, a shaker and centrifuge system separated soil from spent bentonite slurry and conditioned the mud for reuse. This reduced waste volume by 40% and eliminated vacuum-truck hauling of liquid waste. Over 75 operating days, the project recovered 664 m³ of bentonite mud, equivalent to 175,410 gallons of water, and reduced bentonite use by 1,657 kg.<br /><br />Together, the case studies suggest that onsite solids-control and fluid-recycling systems can lower fluid-management and waste-handling costs by an estimated 20–30%. They also reduce fresh-water and additive consumption, transport-related emissions, and risks associated with additional truck traffic. The authors conclude that onsite waste management is increasingly valuable as construction sites become more constrained and disposal costs and environmental requirements rise.

Keywords

onsite slurry treatment

jet grouting

slurry-wall construction

waste reduction

vacuum-truck disposal

centrifuge separation

bentonite recycling

environmental impacts

cost savings

greenhouse gas emissions