New water-management system from PSWS
To help overcome some of the problems often encountered at marine aggregates wharves (limited space, silt disposal, clean water requirements etc), Powerscreen Washing Systems have developed a new water-management and silt-control system that is fully compliant with all current environmental and health and safety legislation and completely eliminates the need for settlement lagoons.
Silt-laden water from the aggregate washing plant is fed into a thickener tank where flocculant is added automatically. The fine solids congeal and fall to the bottom of the thickener while clean water decants over the top of the tank into a clean water storage vessel for reuse in the washing plant. Mains water is used to top-up the system and helps dilute the salt content in the wash water.
The thickened solids are drawn from the bottom of the thickener tank and a proportion is reintroduced to the sand to maximize material recovery and minimize the amount of silt for disposal. The remainder is fed into a buffer tank and then to a plate press. Operation of the press is fully automatic and produces a dry filter cake that is easy to handle. The cake can be used in sub-base-type materials or transported off site for use in landfill restoration.
According to PSWS, the system ensures the most efficient operation possible in this application, providing immediate cost savings by significantly reducing the handling of silt and the volume of water contained in the silt, and by maximizing the sand grading. The equipment can be sized according to the requirements of individual applications but is designed to occupy a small footprint, which is particularly important at wharves where space is limited. The system can also be added to existing washing operations.
