================================== DOCUMENT 6: SESSION 9 (S9) ================================== POLLUTION ABATEMENT (21CHO105T) Unit 1 - Session 9 I. MULTIPLE CHOICE QUESTIONS (MCQs) 1. Which is NOT a cleaner production approach? ● Answer: C) Open dumping ● Explanation: Open dumping is an uncontrolled waste disposal practice, whereas equipment redesign, process substitution, and input changes are established cleaner production strategies. 2. Automation in manufacturing reduces pollution by: ● Answer: B) Improving control accuracy ● Explanation: Automated control systems maintain precise operating conditions (temperature, pressure, flow rate), minimizing off-specification products, chemical spills, and waste generation. 3. Use of renewable energy in processes mainly reduces: ● Answer: C) Fossil fuel emissions ● Explanation: Replacing fossil-fuel power with solar, wind, or bioenergy eliminates greenhouse gas emissions and combustion byproducts ( , , particulates). 𝐶𝑂 2 𝑆𝑂 2 4. Process intensification mainly aims at: ● Answer: B) Reducing waste and energy use ● Explanation: Process intensification creates compact, highly integrated production equipment that drastically lowers energy usage, material inventory, and waste output. 5. Which modification directly reduces hazardous by-products? ● Answer: B) Reaction pathway change ● Explanation: Changing the synthetic reaction route or mechanism can bypass toxic intermediates or hazardous unwanted side-reactions entirely. II. SHORT ANSWER QUESTIONS 1. What is Process Optimization? ● Answer: Process Optimization is the systematic adjustment and fine-tuning of industrial process parameters (such as temperature, pressure, feed rates, residence time, and catalyst ratio) to maximize yield and efficiency while minimizing energy usage and waste output. 2. What is Internal Recycling? ● Answer: Internal recycling is the continuous capture, purification, and direct reuse of waste materials, spent solvents, unreacted reactants, or process water within the same manufacturing facility before they leave the facility boundary. III. LONG ANSWER QUESTION 1. Discuss waste minimization through improved process methods with hierarchy and industrial techniques. ● Answer: 1. The Waste Management Hierarchy The waste management hierarchy establishes a prioritized framework for sustainable pollution management: 1. Source Reduction / Prevention (Most Preferred): Eliminating waste generation at the point of origin through process redesign and material substitution. 2. Recycling and Reuse: Capturing and processing secondary waste streams for internal or external reuse. 3. Treatment: Neutralizing or reducing the toxicity and volume of unavoidable waste via biological, physical, or chemical treatment systems. 4. Disposal (Least Preferred): Safe containment and disposal of residual waste in licensed sanitary landfills or high-temperature incinerators. [ 1. SOURCE REDUCTION / PREVENTION ] <-- Most Preferred [ 2. RECYCLING AND REUSE ] [ 3. WASTE TREATMENT ] [ 4. DISPOSAL ] <-- Least Preferred 2. Industrial Techniques for Waste Minimization ● Equipment Redesign: Upgrading mixing impellers, vessel geometry, and heating configurations to maximize conversion efficiencies and eliminate dead zones. ● Reaction Pathway Changes: Re-engineering chemical reaction steps to avoid hazardous intermediates and increase overall reaction selectivity. ● Process Automation: Installing real-time SCADA systems and distributed control networks to optimize process parameters, preventing runaway reactions or off-spec batches. ● Input Material Substitution: Switching from toxic organic solvents to water-based systems, non-toxic catalysts, or renewable biomass inputs. ● Good Housekeeping Practices: Enforcing preventive maintenance routines to prevent pump seal leaks, pipe corrosion, and material losses during batch transfers.