WATER CLARIFIERS

The PROCESS ENGINEERS Water Clarifier settles fine particles (typically passing 270 mesh or finer) by adding flocculant to the incoming slurry, typically from the overflow of cyclones and/or storm water.  The flocculant is a non-toxic inert hydrocarbon polymer, similar to treatment used in drinking water.  The polymer attracts the charged solids in the slurry causing them to clump together thus gaining enough mass to drop out of solution via gravity.  The mud then settles out to the bottom of the tank and is raked to the center to a thickening cone to be pumped out as thick as possible, typically ~40% solids per volume, to minimize water loss to the ponds.

First the slurry is introduced into the de-aeration tank (shown upper left) where the flocculant is added via a perforated manifold.  Depending on the % solids of your incoming slurry, different kinds of flocculant will be more efficient in settling solids.  Typical slurry consists of 4-8% solids.  Depending where in the range you are, different charges and molecular sized flocculants are available to maximize productivity by keeping polymer costs at a minimum.  PROCESS ENGINEERS routinely does testing to ensure the proper flocculant is being used.  The turbulence is removed from the flow with the baffle, which also increases retention time for polymer mixing.  The slurry is then gravity fed to the clarifiers center feed well where the solids drop out of solution, separating from the liquid.

The solids introduced from the de-aeration tank settle out through the bottom of the center feed well creating a rising current of clean water (can be cleaner than 50 NTU, depending on application).  The clean water flows over a saw-tooth weir (shown left) and is collected in the plant water tank for future use.  Over 90% of the systems water is recycled, losing minimal amounts to product.  The mud collected in the thickening cone can be pumped to a holding pond or to a belt filter press for further de-watering.  Process Engineers uses hard-iron, rubber lined slurry pumps from Georgia Iron Works (GIW) to remove the mud from the tank.  The system comes with a sonic mud level sensor that continually monitors the tank mud level.  This signal can be used to start and stop the underflow pump.

PROCESS ENGINEERS clarifiers come with bridge and access stairwell with a 36 handrail (shown left).  A NEMA 4 (rated for outdoor use) enclosed panel containing motor starters for the clarifier drive and underflow pump and valves is typically mounted on the bridges handrail.  On clarifiers larger than 20 in diameter, a lift mechanism is required.  In an upset condition, the units with lifting capabilities will automatically raise the rake if the torque reaches a specific plateau, preventing damage to the drive.  A 1 flush line to the discharge cone is standard on all units.  This is for high pressure air or water to be used to flush the system should an upset condition occur