Polymer in zero liquid discharge plants
Why the clarifier at the front of a ZLD train decides how hard the membranes and evaporators behind it have to work.
What ZLD means
A ZLD plant sends no liquid effluent out. Water is recovered for reuse and dissolved salts leave as solids.
Who runs it
India's 2015 ZLD guidelines covered textiles, tanneries, distilleries and pulp and paper. Tiruppur's dyeing units have worked under a ZLD requirement since 2008, and many pharma plants run ZLD too. Your consent order says what applies to you.
Front end first
The train starts with coagulation, flocculation and settling, usually followed by biological treatment. Solids that escape this stage foul the RO membranes downstream.
Where Sunfloc fits
A well-chosen flocculant keeps the primary clarifier overflow clear, protecting softening, filtration and RO. Textile and tannery front ends usually use Cationic HQ or Cationic MQ.
Sludge
ZLD plants make a lot of sludge at the front end; a cationic grade helps it dewater before disposal.
Related
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Starting doses, solution strength and how to work out kilograms per day.
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