Electrochemical system with concentration recirculation in cyclic batch mode
AssigneeEvoqua Water Technologies LLC
InventorsLi-Shiang Liang, Michael J. Shaw, Wenxin Du
Life of this patent
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Abstract
A method of operating an electrochemical device includes periodically discharging a volume of concentrate reject in a timed batch cycle and replacing the concentrate reject with feed water. An electrochemical water treatment system includes a recycle line having a valve controlled by a control module. The control module periodically opens the valve to discharge concentrate reject from the recycle line in a batch timed cycle. The recycle line is fed with feed water to replace the discharged concentrate reject.
Claims11
A method of operating an electrochemical separation device comprising a dilution compartment, a concentration compartment, an ion exchange membrane positioned between the dilution compartment and the concentration compartment, first and second electrodes, a first feed stream fluidly connected to the dilution compartment, a second feed stream fluidly connected to the concentration compartment, and a concentration compartment recycle stream the method comprising:
- directing the first feed stream to the dilution compartment to produce a product stream;
- directing the second feed stream to the concentration compartment to produce a reject stream;
- recycling the reject stream to the concentration compartment;
- measuring electric current between the first and second electrodes;
- periodically discharging a volume of the reject stream having a first concentration of ions in a batch cycle;
- and
- replacing the discharged volume of the reject stream with an essentially equivalent volume of the second feed stream having a second concentration of ions lower than the first concentration of ions,
- the batch cycle being determined by the electric current between the first and second electrodes, the method comprising discharging the volume of the reject stream when the electric current decreases to reach a predetermined value.
Dependencies are inferred from the claim text.