Sediment is a naturally occurring material broken down by weathering and erosion. It is subsequently transported by wind, water, or ice or by the force of gravity acting on the particles. For example, sand and silt can be suspended in river water and reach the sea bed deposited by sedimentation; if buried, they may eventually become sandstone and siltstone (sedimentary rocks) through lithification.
The natural flow of water commonly causes regular dredging of local waterways. Other than mining, the most common use for a dredge is reservoir dredging. Some cities and municipalities source the community’s water from open-air reservoirs. Sometimes, these reservoirs silt in or become contaminated with the material. Dredging is an efficient and effective way to keep these reserves clean.
Sediments are often transported by water (fluvial processes), wind (aeolian processes), and glaciers. Beach sands and river channel deposits are fluvial transport and deposition examples, though sediment often settles out of slow-moving or standing water in lakes and oceans. Desert dunes and loess are examples of aeolian transport and deposition. Glacial moraine deposits and till are ice-transported sediments.
Some of Our Cleanup Remedies and Technologies :
- In situ treatment commonly involves adding treatment amendments to accelerate contaminant removal or immobilize the contaminant. Modifications for sediment treatment include organophilic clay, zeolites, bauxite, iron oxide/hydroxide, apatite, and zero-valent iron. However, the most common approach is activated carbon (AC) as a thin-layer cap or incorporated into the sediment.
- Monitored natural recovery takes advantage of biological processes, including the natural burial of contaminated sediments with clean sediments.
- Capping involves the placement of clean material over contaminated sediments. When contaminants are relatively immobile in deposition, a cap prevents flora and fauna from contacting them. A relatively impermeable cap can prevent groundwater from discharging through the contaminated sediment. The cap thereby diverts the groundwater away from the contaminated area.
- Dredging or Excavation removes contaminated sediment from a water body without draining or diverting the water. Dredging also removes a certain amount of water from the sediment. The deposits are usually dewatered on land, and the water is generally treated before being discharged back to the water body or public treatment works. The contaminated sediment is disposed of in a landfill or a confined disposal facility. Highly contaminated sediment may be treated before disposal.
Risk Management and Remedy Planning Solutions
- Strategic and technical planning
- Regulatory/Stakeholder group assistance
- Empirical and numerical modeling
- Ecological and human health risk assessments
- Bench and pilot-scale studies
- Integrated shoreline development and contaminated sediment management
- Remedial alternatives analysis
- Sediment remediation design
- Remediation Engineering Services
- Phase I / Site Assessment Services
- Risk Assessment & Toxicology Services
- Visual presentations of proposed remedy and technical and risk communications
- Permit acquisition
- Construction management/turnkey solutions
- Site restoration
- Remedy performance monitoring
- Natural Resource Damage assessment assistance