Question

Sludge from painting operations is an example for __________ waste category.

(a) Organic aqueous

(b) Inorganic aqueous

(c) Organic liquid

(d) Organic sludge

This question was addressed to me in a national level competition.

This intriguing question originated from Engineering System Classification in chapter Classification of Hazardous Waste of Hazardous Waste Management

Answer 1

Correct answer is (d) Organic sludge

To elaborate: Sludge from painting operations, tar residues from production of dye and distillation bottom tars are example of organic sludge waste.