Separating the debris, gravel, and granular material from the fine, contaminated sediment is an important step that will simplify the final dewatering and water treatment processes. It is also an opportunity to reduce the project cost and to potentially find beneficial uses of some of the materials. Brennan has developed several methods to efficiently separate the materials while keeping pace with dredge production.
There are several methods of slurry separation that serve multiple purposes. Many times they are set up in stages to separate materials of different sizes. Larger materials such as debris and aggregates are separated out before the dewatering process begins. This reduces the costs of overall dewatering because it creates a more homogenous sediment mixture that can be treated more easily with polymers. Larger materials do not require polymers for water separation and cause density meters to overestimate density measurements. This typically leads to over-treatment of the slurry.
Often, the size of the dewatering area will limit selections; however, it has been found that implementing a material separation process before dewatering the slurry will both increase production rates and reduce the overall project cost.
Methods of Material Separation
- Sand Wheels
- Vibratory Conveyors
- Trammel Screens
- Vibratory Screens
- Thickener Units