| Water- Recirculation and Treatment Plant | |
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For a typical post consumer plastics washing and recycling plant with a capacity
of about 10,000 t/y the water consumption (in closed loop) is as follows:
| Washing water | Cooling water | ||
| Sink-Float Tank | 200 Lit./min | Turbowash |
23 Lit./min |
| Turbowash | 146 Lit./min | Dynamic Centrifuge | 23 Lit./min |
| Dynamic Centrifuge | 78 Lit./min | Densifier | 70 Lit./min |
| Steam Cleaning | 70 Lit./min | ||
| ML 1400 |
up to 250 Lit./min |
ML 1400 | 70 Lit./min |
Total water flow (closed loop) 610 lit/min
corresponds about 36 m3/h.
Estimated requirement for water treatment and substitution (values without
guarantee):
Water loss due to evaporation (incl. Steam
Cleaning System), residual humidity of the material and water in the
sedimented slick. Estimated loss about 1,5-2 m3/h.
Water Treatment: Assumption: Post consumer plastics contamination for 1,3 t
plastics/h corr. to about 130 kg/h
Slick: Relation water/solid material 10 : 1, i.e. at full recuperation about 1,3
m3/h must be treated.
Total requirement for treatment and substitution: about 3 m3/h.
Technical Description:
The plant is designed to sediment the suspended dirt particles in 3 consecutive
steps.
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The water
backflowing from the Sink-Float Tank is discharged into a vessel and from
there to an intermediate storage sink. The water discharged from the
centrifuges flows directly to this sink. From there the water is pumped to
the vibration sieve Nr. 1, made of INOX with a mesh of 300 µm. Most of
the paper is separated here. From there the filtered water discharges to the 2nd sieve with mesh size of 100 µm. The water folws into a tank and from there it is pumped to the 2 large double walled sedimentation vessels of each 45 m3. |
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The 2
double walled sedimentation vessels have the double function, to feed the
water to the filter presse and secondly, during the self cleaning of the
filter press (duration 6 minutes every 5-6 operation hours), tosafeguard
the water suppply to the washing plant out of the inner vessel. The filter
press separates all suspended particles up to 30 - 40 Micron. Finally the cleaned water is stored in large pools 120 m3 for recirculation. These pools also serve as storage for the large water quantity in closed circuit. |
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