Any business requiring a dewatering system needs to carefully consider the container size. This is not only important for the volume of sludge and water flowing into the dewatering container, but it will also determine how frequently the container will need to be emptied.
Most companies will offer at least two different sizes of dewatering units. These are offered as roll-off units, which then allows the company to use a pre-selected service to haul off the unit when it is full, or they may choose to invest in a truck with a hook life and roll-off container system for their own disposal.
The most common sizes are the fifteen and thirty-yard roll-off dewatering container. Keep in mind; the size is the volume of dewatered solids the unit can hold, not the amount of liquid the unit will process. As the volume of solids builds, the amount of liquid in the tank will decrease.
Both options in dewatering unit sizes will also need a separate polymer mixing and dosing unit. There will also be a pump used, with both units requiring the same systems.
The 30 cubic yard container will be able to process 22,000 to 25,000 gallons of liquid with up to 2% solids. The 15 cubic yard roll-off container will be capable of dewatering between 10,000 and 12,000 gallons with the same rate of 2% solid materials.
While the larger dewatering container is more costly than the small unit, it also provides for a greater time between dumping, which can reduce the long-term costs of operation of the system.
Additionally, with the added capacity, a business can charge for other companies to use the dewatering system, which will generate revenue from the container. Depending on the solids present, it may also be possible to sell the dewatered solids, which is also a cost benefit to consider with a larger sized container.