PELLU
Continuous Treatment Process
for Heavy Metal Removal from Wastewater
The PELLU process of heavy metal removal
from wastewater can be a batch
treatment process or in a
continuous treatment process. The continuous-flow process control mode can be either semi-automatic or fully
automatic. Laboratory and/or
pilot studies will establish the required combination and dosing of
PELLU chemicals.
Stable wastewater: In this situation,
the metal content is always
out of compliance. Continuous dosing of PELLU chemicals is required.
The pH setpoint is the process control setpoint (e.g., metal refinery).
Unstable wastewater: Manufacturing process requires a lot of
rinse water. Sometimes metal content in wastewater is already below
compliance level. Process control efficiency and cost effectiveness
does not require continuous dosing of PELLU chemicals (e.g. electroplating/printed
circuit board shops). Oxidation-reduction potential (ORP) and pH set
points are the process control set points.
PELLU continuous process
flow diagram for metal removal from waste water
Typical PELLU
Continuous Treatment
System
- Wastewater type:
Chelated/complexed spent electroplating bath.
- Flow rate: 50 gallons per minute (gpm).
- Systems unit: Fully automated with a programmable logic controller
(PLC), supervisory control and remote data acquisition (SCADA), alarm
paging capabilities and virtual instrumentation.
- Process control: In a typical process, the high-level float switch
in the sump activates the PELLU chemicals dosing pumps. The stroke/speed
knobs for these pumps are set based on bench scale and/or pilot studies.
Wastewater flow through the treatment system is by gravitational movement. After chemical precipitation, coagulation/flocculation in the treatment
tank, rapid liquid/solids separations then place in the clarifier with
clear water at the top and metal-laden sludge at the bottom. High
quality clear water can be directly reused, be further
refined, or
dumped to the local municipal sewer.
- Throughput time: Very fast.
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60 GPM Continuous Flow Unit
- Hydraulic flow rates: 5
to 1000 GPM
Construction:
3-chamber, double-wall.
- Footprint: 5' x 5'
x 8'
- Operation:
Automatic or semi-automatic.
- Controls: Programmable logic
controller (PLC), supervisory control and remote data acquisition
(SCADA), and alarm paging capabilities.
- Operator interface: Virtual instrumentation.
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