| Biosolids are
conditioned with polymers using an in-line venturi-type mixer. The amount of
turbulence in the mixer, as well as its position in the pipeline, can be
varied to optimise mixing energy and flocculation time for optimum release
of free water. The conditioned biosolids are gently distributed across the
belt width using a stainless
steel distribution box. The distribution box is the same width as the belt,
eliminating the need for baffles or vanes to direct the biosolids across the
belt width, while minimizing turbulence. The absence of vanes makes the box
very easy to keep clean, while the low turbulence avoids breaking up fragile
floc to minimize polymer consumption. For biosolids with higher solids
concentrations, a stainless steel levelling dam ensures that the biosolids
are spread evenly across the entire belt width for maximum capacity. Once
the biosolids are distributed onto the belt, a series of plows furrow and
roll the material. The furrowing action opens up drainage channels on the
belt where filtrate released by the polymer conditioning can drain away. The
rolling action brings filtrate that is ponded on top of biosolids in contact
with the belt. A key to achieving adequate rolling and furrowing actions is
the plow contact length. The plows float so they remain in belt contact as
they wear, but safely allow obstructions to pass beneath them. Handles allow
each row of plows to be lifted from either side of the press for easy
cleaning.
Polymer
Blending Unit
The Polymer Blending Unit is where the polymers is mixed with water before
injecting it into the sludge or as it called today bio-solids. The polymer
causes the solids to clump to gather like lager cured cottage cheese. When
used with the belt thickener we can take solids that are ½% solids up to
5-8% solids. This reduces the amount of solids we must handle by ten to 16
time less. The liquid that comes off the belt is return to the head of the
plant for further treatment.
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Polymer Blending
Unit |
Sludge Inlet |
The photo above left is the Polymer
Blending Unit. The photo on the right is where the bio-solids are just
entering the Thickener belt after the polymers have been added. At this
point the solids have started clumping together and the water is separating
form the solids.
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Other End of Sludge
Belt |
The photo above shows the other end of the
sludge belt. As can be seen here, the plows are separating the sludge on the
belt, making areas for the water to drain though the belt. Summary
The J-Flow Gravity Belt Thickener is a proven means of dost-effectively
reducing the volume of municipal wastewater sludge streams and industrial
process slurries. The J-Belt utilizes the principle of liquid/solid
separation by gravity drainage. The J-Flow is a continuous dewatering device
requiring little to no operator attention and operates on very low energy
costs.
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