Biological Treatment of Industrial Wastewater and Toxicity Control
Some industrial wastewater is treated biologically, and a separate national certification exists
for biological industrial waste treatment alongside the physical/chemical one. But
industrial biological treatment is not municipal activated sludge with a different sign on the
gate: the influent is nutritionally unbalanced, intermittent, sometimes hot, sometimes saline and
sometimes toxic.
The nutrient problem
Domestic sewage arrives nutritionally balanced. Industrial wastewater from food, dairy, brewing,
sugar and pulp and paper operations is rich in organic carbon and deficient in nitrogen and
phosphorus. A nutrient-deficient biological system produces poor floc and favours filamentous
organisms, so the sludge bulks and will not settle.
The starting point for supplementation is the classic design r