================================== DOCUMENT 6: SESSION 6 (S6) ================================== POLLUTION ABATEMENT (21CHO105T) Unit 2 - Session 6 I. MULTIPLE CHOICE QUESTIONS (MCQs) 1. Anaerobic digestion of MSW produces: ● Answer: B. Biogas ● Explanation: The anaerobic digestion of municipal solid waste (MSW) organic fractions yields biogas alongside nutrient-rich digestate. 2. Recycling of MSW helps in: ● Answer: B. Conserving natural resources ● Explanation: Recycling materials like paper, metal, glass, and plastic reduces the extraction and consumption of virgin natural resources. 3. Refuse-Derived Fuel (RDF) is prepared from: ● Answer: C. Combustible fraction of MSW ● Explanation: RDF processing isolates the high calorific, combustible fraction of municipal solid waste for fuel utilization. 4. Autoclaving is a method of: ● Answer: B. Thermal sterilization using steam ● Explanation: Autoclaving utilizes saturated steam under pressure inside a sealed chamber to achieve microbiological sterilization of medical and biomedical waste. 5. Which of the following biomedical waste types is suitable for autoclaving? ● Answer: C. Microbiological waste ● Explanation: Laboratory cultures, microbiological waste, sharps, and soiled linen are routinely treated and sterilized via autoclaving prior to shredding and final disposal. II. SHORT ANSWER QUESTIONS 1. Describe the processing methods used for municipal solid waste. ● Answer: 1. Source Segregation & Manual Sorting: Separating wet, dry, and recyclable components. 2. Mechanical Separation: Utilizing trommel screens, magnetic separators, and air classifiers to sort recyclables. 3. Composting & Biogas Production: Biological decomposition of organic MSW fractions. 4. RDF Production & Incineration: Converting combustible fractions into fuel pellets or thermal energy. 2. Why does biomedical waste require special processing? ● Answer: Biomedical waste contains infectious pathogens, hazardous chemicals, sharp needles, and pharmaceutical residues that pose severe public health risks, disease transmission hazards (e.g., Hepatitis, HIV), and environmental contamination if mixed with general municipal waste. Special processing (autoclaving, incineration, microwaving) ensures complete pathogen inactivation. III. LONG ANSWER QUESTION 1. Describe the processing methods used for municipal solid waste. ● Answer: 1. Mechanical Processing and Sorting ● Trommel Screens & Size Reduction: Rotating cylindrical screens separate waste fractions based on particle size; shredders reduce bulky items. ● Magnetic & Eddy Current Separation: Electromagnets extract ferrous metals, while eddy current separators repel and recover non-ferrous metals (aluminum). 2. Biological Processing Methods ● Aerobic Composting: Windrow, in-vessel, or vermicomposting processes convert organic kitchen and garden waste into stable, nutrient-rich soil humus. ● Anaerobic Digestion (Biomethanation): Wet organic waste is broken down by anaerobic bacteria in enclosed bioreactors to generate biogas and bio-fertilizer. 3. Thermal and Energy Recovery Processing ● Incineration: Direct high-temperature burning of municipal solid waste with energy recovery. ● Refuse-Derived Fuel (RDF): Processing, drying, and pelletizing combustible solid waste fractions for industrial co-processing in cement kilns and power boilers.