Question

UASB stands for

• A. Upflow aerobic sludge blanket
• B. Uptake aerobic slime blanket
• C. Uptake anaerobic slime blanket
• D. Upflow anaerobic sludge blanket

Hint:

Remember: UASB is always an anaerobic process (no aeration needed) and involves a sludge blanket inside an upflow vessel. This distinguishes it from trickling filters and activated sludge processes.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Dairy processing generates high volumes of wastewater containing high levels of organic matter (lactose, proteins, and milk fats).
This high Chemical Oxygen Demand (COD) effluent requires efficient treatment before discharge.
The UASB reactor is a highly efficient anaerobic treatment system designed for high-strength organic industrial effluents.

Step 2: Detailed Explanation:
UASB stands for Upflow Anaerobic Sludge Blanket.
Let us break down this technical term to understand its design:
- Upflow: Wastewater enters from the bottom of the reactor and flows slowly upward through the system.
- Anaerobic: The process operates in the complete absence of dissolved oxygen.
- Sludge Blanket: The core of the reactor contains a suspended blanket of highly active, granular anaerobic microorganisms.
As the organic-rich wastewater flows upward through this dense microbial blanket, anaerobic bacteria digest the dissolved organic compounds (sugars, fats, and proteins), converting them into biogas (a mixture of methane, \(\text{CH}_4\), and carbon dioxide, \(\text{CO}_2\)).
At the top of the reactor, a three-phase separator splits the treated effluent, the granular sludge (which settles back down), and the generated biogas (which is collected as renewable energy).
UASB reactors are widely preferred in the dairy industry due to their low footprint, low energy consumption, minimal sludge generation, and high COD removal efficiency (often \(> 85\%\)).

Step 3: Final Answer:
UASB stands for "Upflow anaerobic sludge blanket".