TECHNOLOGY FOCUS - BIOLOGY - Preferred Composition: The microbial composition comprises (in vol.%): starch degrading bacteria (18), oil degrading bacteria (22), protein degrading bacteria (20) and cellulose degrading bacteria (10). Preferred Method: The method involves (a) (i) culturing the starch degrading bacteria in enriched medium comprising soluble starch, peptone, sodium chloride and water in a mass ratio of 4:1:1:200 and having pH of 6-8, (ii) performing primary screening the starch degrading bacteria in medium comprising soluble starch, rice, peptone, sodium chloride and water in a mass ratio of 1.6:2.4:1:1:200 and having pH of 6-8, (iii) performing secondary screening of the starch degrading bacteria in culture medium comprising soluble starch, rice, peptone, sodium chloride, agar and water in a mass ratio of 1.6:2.4:1:1:4:200 and having pH of 6-8, and (iv) re-screening the starch degrading bacteria in culture medium comprising rice, peptone, sodium chloride and water in a mass ratio of 4.8:1:1:200 and having pH of 6-8, (b) (i) culturing the oil degrading bacteria in enriched medium comprising peptone, beef extract, sodium chloride, soybean oil and water in a mass ratio of 2:1:1:200 and having pH of 6-8, (ii) performing primary screening of the oil degrading bacteria in medium comprising peptone, beef extract, sodium chloride, soybean oil and water in a mass ratio of 2:1:1:3.2:200 and having pH of 6-8, and (iii) performing secondary screening of the oil degrading bacteria in medium comprising peptone, beef extract, sodium chloride, soybean oil, agar and water in a mass ratio of 2:1:1:3.2:4:200 and having pH of 6-8, (c) culturing the protein degrading bacteria in enriched medium comprising casein, sodium nitrate, disodium hydrogen phosphate, potassium chloride, magnesium sulfate, ferrous sulfate, cane sugar and water in a mass ratio of 12:2:1:0.5:0.5:0.01:30:1000, (ii) performing primary screening of the protein degrading bacteria in medium comprising egg or lean meat, sodium nitrate, disodium hydrogen phosphate, potassium chloride, magnesium sulfate, ferrous sulfate, cane sugar and water in a mass ratio of 20:2:1:0.5:0.5:0.01:30:1000, and (iii) performing secondary screening of the protein degrading bacteria in medium comprising egg, lean meat, sodium nitrate, disodium hydrogen phosphate, potassium chloride, magnesium sulfate, ferrous sulfate, cane sugar and water in a mass ratio of 20:2:1:0.5:0.5:0.01:30:15:1000, and (d) culturing the cellulose degrading bacteria in enriched medium comprising peptone, yeast, sodium carboxymethyl cellulose, ammonium sulfate, monopotassium phosphate, magnesium sulfate heptahydrate, ferric sulfate heptahydrate, manganese chloride, sodium chloride, agar and distilled water in a mass ratio of 3:3:5:2:2:1:0.01:0.005:3:20:1000 and having pH of 6-8. The method involves (a) isolating starch degrading bacteria from sludge sample under sterile conditions, adding starch liquid (125 ml, pH 7) to Erlenmeyer flask, culturing the solution in shaker at 30 degrees C and 150 revolution per minute (rpm) for 7 days, transferring 1 ml of starch liquid (3 g, 4 g, 5 g and 6 g) for 6 times, screening the bacteria having highest degradation rate to prepare seed liquid, and refrigerating the seed liquid at 4 degrees C, (b) isolating oil degrading bacteria from sludge sample under sterile conditions, adding starch liquid (125 ml, pH 7.2) to Erlenmeyer flask, culturing the solution in shaker at 37 degrees C and 150 revolution per minute (rpm) for 7 days, transferring 1 ml of starch liquid (3 g, 4 g, 5 g and 6 g) for 6 times, screening the bacteria having highest degradation rate to prepare seed liquid, and refrigerating the seed liquid at 4 degrees C, and (c) isolating protein degrading bacteria from sludge sample under sterile conditions, adding starch liquid (125 ml, pH 7) to Erlenmeyer flask, culturing the solution in shaker at 30 degrees C and 150 revolution per minute (rpm) for 7 days, transferring 1 ml of starch liquid (3 g, 4 g, 5 g and 6 g) for 6 times, screening the bacteria having highest degradation rate to prepare seed liquid, and refrigerating the seed liquid at 4 degrees C. The carrier is prepared by mixing straw powder, bran and activated carbon in a mass ratio of 1:1:0.01 and sterilizing mixture. The carrier and microbial composition is mixed in a mass ratio of 1:49.