CHAPTER 6 DESIGN OF USAB REACTOR FOR THE MUNICIPALITY OF ERODE ON MUNICIPAL SOLID WASTE

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1 155 CHAPTER 6 DESIGN OF USAB REACTOR FOR THE MUNICIPALITY OF ERODE ON MUNICIPAL SOLID WASTE 6.1 GENERAL In order to improve the current solid waste management services it is essential to explore the various constraints or issues and to arrive at a suitable solution. Municipal solid waste management involves a whole community and sufficient actions have to be taken to realize its full potential. Community participation is the process by which individuals and families understand responsibility for their own health and welfare of societies. The key to the success of solid waste management system in any city lies in the cooperation of citizens. This community participation requires considerable planning and management. 6.2 PRESENT SCENARIO OF STUDY AREA AND EXISTING FACILITIES FOR MSW MANAGEMENT Town Profile and Source of Waste Generation Name of the study area Area : Erode Municipality : 8.44 sq.km Census Population : 1, 51,274 Population : 1,60,350 Population : 1,77,038

2 156 Number Wards : 45 Number of streets : 469 Length of Roads : kms Length of S.H. Road : kms Length of drainage : km. Slums : 52 Slum population : 38,808 House Holds : 37,511 Total No. of Buildings : a. Residential : b. Industrial : 32 c. Commercial : 6648 d. Institutions : 327 e. Municipal buildings : 120 Special buildings; a. Cinema theaters : 14 b. Lodges : 42 c. Hotels : 159 d. Kalyanamandapam : 30 e. Commercial complex : 32 Institutions; a. Government Offices : 63 b. School and Colleges : 60 c. Hospitals : 80

3 157 d. Dispensaries : 136 e. Noon meal centre : 46 f. ICDS(Integrated child development systems) : 82 g. Market : 5 h. Bus stand : 1 i. Railway station : PROPOSED FULL SCALE UASB REACTOR FOR A CITY Based on the results obtained from the present lab study it is recommended of a full scale biomethanation plant may be commissioned in the field to produce the thermal energy and electrical energy using MSW. The solid waste normally generated about 135 to 150 metric tons of per day in the town. The estimation and prediction of municipal solid waste generation plays an important role in solid waste management. The population growth, migration of people, underlying economic development, house hold size, employment changes and the impact of waste recycling are the factors that influence solid waste generation interactively. This chapter discusses the proposed biogas plant for the town through the results obtained from the laboratory scale model and manages the solid waste in the eco friendly manner towards the sustainable economic growth. The reactor design fulfils the design parameters of Lettinga (2001).

4 m 50 Ph Pv = 1.64m 5.0m m 2.20m (a) 3.20m m 0.8m (a) GAS HOODS, (b) SETTLER COMPARTMENT (b) Figure 6.1 UASB Reactor full scale model Erode city produces around 100 tones of organic waste every day (i.e100, 000 Kg of waste). 4L of water or municipal sewage could be added to each Kg of solid waste. Then 400,000 L of waste water generated for treatment (400MLD). (In view of cost of water utilized for hydrolysis of MSW the municipal sewage can be mixed and diluted before feeding the waste in to UASB reactor)

5 159 DESIGN PARAMETERS Up Flow Velocity Assume full depth of reactor (including settler) = 5m Hydraulic retention time = 12hr Depth of sludge blanket = 2.2m Up flow velocity at average flow = 5m/12hr = 0.416m/hr say 0.5 m/hr Reactor Dimensions Reactor Area Required: 3 Total Flow m /d Up flow velocity m /d 0.5m / hr x 24 = m 2 say 40m 2 free board. Hence provide 8m length x 5m width x 5m side water depth + 0.5m Check for organic loading rate: Volumetric organic loading = COD Load Vol of reactor COD = 1000g/m 3 (from lab experiment) g / m x 400 m / d 1000 x 8x5x5 = 2gCOD/m 3 /d (acceptable)

6 160 Total COD Removed = 80% of incoming load g / m x 400 m / d = 320 kg/d 1000 Gas Collector Design No. of gas collector = 5m/4m (each 8m length) Aperture width Aperture area required 3 Peak Flow m / hr Permissible Aperture velocity m / hr m / d x 2 5m / hr x 24 = 6.67m 2 Aperture width Aperture area Length of aperture x No of Aperture m x1no = = say 0.8m Provide inclined plate of gas collector at 50 0 to the horizontal Horizontal width of plate (p h ) = [total gas collector width Aperture width Hood width + overlap of gas collector over hood width] /2

7 = 1.375m P v = vertical height of plate collector = Tan (50 0 ) x P h = m (say 1.64) Deflector beam Width of deflector beam = Aperture width + 2 (overlap) = (0.1) = 1m surface loading = (400m 3 / day) / settler width x length x nos Surface loading x 8 x 1 = m 3 /m 2 /day. 6.4 FISCAL ANALYSIS REPORT The fiscal analysis report was also prepared for design, implementation and maintenance of the project. The commercial prospects of the pilot scale plant are its cost benefit analysis for OFMSW digestion plants are given below. It was calculated that the municipality generates 100 to 135 tons of municipal solid waste per day. The biogas production for 100 tones (100,000 kgs) of bio degradable waste per day is taken for consideration Based on the lab study UASB reactor produces 0.5m 3 1.0m 3 of biogas. Biogas production for the 100,000kgs of waste = 50,000m 3 /day Total amount gas generated per month = 15, 00,000m 3 Conversion of biogas into thermal energy Thermal energy Equivalency 1 m 3 of bio gas = 0.43 kg of LPG Cost of commercial LPG for

8 162 Municipality vehicles = Rs.25.30/kg (approx.) Total LPG replaced per month = 15, 00,000 x 0.43 = 6, kg Total money save per month = Rs.1, 63, 18,500 = Around 1.63 crores Electrical energy 1 m 3 of bio gas contains 6.3 kw of electrical energy. During the feeding to electrical generation it will offer only 2.1 kw. The 1 kw of electricity is around Rs. 5. Total unit generated per month is = = kw Total money saved per month is = 31,50,000 5 = Rs.1,57,50,000 =Around 1.5crores This analysis could be useful for the field application. The rate of hydrolysis in the acidogenic reactors to be enhanced using the series of acidogenic reactors and the leachate recycled and feed into the UASB reactor. Hence the smooth operation UASB reactor conformed then COD removal biogas production are obtain effectively. Two phase anaerobic system is very flexible in operation and more reliable for organic solid waste treatment.