Question

Spent wash is a major pollution problem in which industry?

• A. Fertilizer industry
• B. Petroleum refinery
• C. Sugar industry
• D. Cement industry

Hint:

Logic Tip: "Wash" refers to the fermented liquid before distillation. "Spent wash" is what is left over (spent) after you boil the alcohol out of it. Since the alcohol comes from sugar cane molasses, it belongs to the Sugar industry.

Answer 1

The Correct Option is C

Concept:
Different chemical industries produce highly specific, characteristic waste streams. Identifying these streams is a core part of industrial pollution control.

Step 1: Spent wash is a dark brown, foul-smelling, highly acidic liquid effluent with an extraordinarily high Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD).

Step 2: It is the primary liquid waste product generated during the distillation of fermented molasses to produce ethanol (alcohol).

Step 3: Molasses is the heavy, dark syrup byproduct left over after sugar is extracted and crystallized from sugarcane juice. Therefore, distilleries are almost always deeply integrated into the sugar manufacturing complex.

Step 4: Because it originates from molasses fermentation, spent wash is universally classified as the major pollution problem of the sugar and distillery industry.