Aggregate Wash Plant

SITUATION

At an aggregate wash plant, pit run is washed to remove finer particles to upgrade aggregate quality for various uses. The by-product is water laden with fine particulate. At this particular site there was a need to reduce the turbidity and total heavy metal value for a 4,000 gallon per minute flow discharging into a local fish-bearing stream. When the turbidity of the receiving stream reached a threshold value the plant was forced to shut down until acceptable levels were reached; this caused lost production time. The facility as it had been initially constructed, had four settling ponds in series that would create a 7-day retention time before discharging into the stream; this was insufficient for removal of particles smaller than 10 microns.

SOLUTION

A mixing grid was constructed in situ with the pond settling system and incorporated ClearfFlow's Water Lynx product to flocculate the suspended solids. This flocculation of particles caused the solids to settle out of suspension when the water entered the settling pond.

 RESULTS