Waste Treatment Technologies
We must swallow these truths
Some wastes are not worth being treated.
Yes, you would like to recycle, but that’s not always feasible.
Some materials are worth more on the recycling market than others.
We will never get to zero waste.
Primary treatment. Sometimes called mechanical treatment. remove colloidal solids, emulsified oil and a small portion of BOD and COD
1) Equalization tank. Acts as buffer. Smooths variations in flowrates and contamination loads. Concrete tank with coating.
2) Screening. Sedementation by gravity. neutralization (i.e., pH adjustment), coagulation, flocculation and dissolved air flotation (DAF).
Coagulation and flocculation. Wastewater from the neutralization tank usually flows by gravity into coagulation tanks for removal of colloidal solids.
A coagulant solution (typically polymer based) usually is injected automatically by dosing pumps (“1+1” configuration);
Coagulation is a quick process, requiring a relatively low retention time of 2–5 min.
Wastewater from coagulation tanks most often flows by gravity into the flocculation system (tanks) where agglomeration of flocculent formed during coagulation process takes place. Anionic polymer usually serves as flocculent.
Wastewater from flocculation passes by gravity into a DAF clarifier system.