Engendering of Electricity from Waste Material: A case study in Agartala City

: The management of municipal solid waste has emerged as a key issue in contemporary city planning. The amount of solid garbage generated on a daily basis is forcing policymakers to implement sustainable waste management techniques. Recycling and the secure elimination of dangerous waste materials with a reasonable calorific value are both included in waste management. Considering the aforementioned fact, an attempt is made to evaluate the potential of MSW generated in Agartala city for the generation of electricity. In this study, we have analyzed two different methods to recover energy from waste such as Thermal Power-plant and Biogas Power-plant. Agartala Municipal Corporation (AMC) collects 250 MT of waste per day from different sources. In this study it is seen that 54.5 MT (22% of total waste) of waste can be used for thermal power-plant from which 1.4 MW energy can be produced. But 78% of waste is still left which can also be utilized them in Biogas power plant to produce energy

Nezih Kamal Salihoglu (2018) studied the waste to energy alternative in Turkey for the landfill gas to energy plants.The landfill gas to power plants of urban landfill was surveilled for three years and the installed capacity and actual operating hours of the gas engines were noted based on the field data parity was derived to calculate the energy capacity for such plants for a quantum of waste.Barragan-Escandon et al (2020) studied the potential of biogas production in the Ceibales landfill in the southern region of Ecuador.In the study the biogas production potential is evaluated through mathematical models.The study considered the feeding of the produced biogas into power plant for energy generation.
The mathematical model is developed and analysed by characterizing and accounting for the landfill data.
The best technology for producing electricity is determined after determining each source's generating capacity.

Sources of wastes:
Waste sources can be broadly categorized into four categories: ➢ Industrial Waste: Waste generated in factories and other industries is referred to as industrial waste.
The majority of industries pollute rivers and seas by disposing of their trash there.➢ Commercial Waste: Offices, stores, colleges, and schools all produce commercial garbage.➢ Domestic Waste: Domestic waste refers to the various types of waste that are gathered from household chores like cleaning and cooking.➢ Agriculture Waste: Agriculture wastes are any number of wastes generated in the agricultural sector.

Biodegradable waste:
These wastes, consisting of leftover food and garden waste, originate from our kitchen.Humid waste is another name for biodegradable trash.Composting this will yield manure.Depending on the material, biodegradable wastes take a while to break down.

Non-biodegradable waste:
These wastes originate from the kitchen and include plastics, broken glass, and other materials.Dry waste is garbage that is not biodegradable.Dry trash has two recycling and reuse options.Non-biodegradable wastes are significant pollutants since they cannot break down on their own.

Primary Collection of Municipal Solid Waste under AMC
Primary collection is the practice of waste collection from its very source of generation.Primary collection includes 'house to house' for 'door to door' collection, collection of waste from commercial units like shops, hotels and restaurants.House to house garbage collection under some wards of AMC is being done by NGOs using tri-cycles and auto rickshaw.Rs. 30/house per month is being charged by the NGO as user fee.Efforts are going on to give the service six days in a week and to further improve the system by procuring new small auto trucks.Present Coverage: 30 to 40 %

Secondary collection of Municipal Solid Waste under AMC
Agartala Municipal Council has placed more than 500 number of medium (1.1 cu meter) and large size (4.5 cu.Meter) Bins/containers by the side of major roads and in market and commercial areas.Daily more than 400 sweeping staff sweeps the roads and market areas and garbage is collected in above said bins.Also one sweeping machine is also engaged for sweeping roads where there is footpath by the side of road.

Transportation:
Solid Waste thus generated is transported to the dump yard of Agartala Municipal Council which is about 15 km away from the main city of Agartala.On an average 25 vehicles of Agartala Municipal Council move daily twice or thrice for this purpose.As per the standard calculation about 40 vehicles make three trips for the Dump-yard.For this 280-300 no of labours from Mechanical section of Agartala Municipal Council are engaged, majority in morning and some in after noon shift for lifting the garbage from the roadside and from the drains and also from various dustbins/containers.All the vehicles of Mechanical wing are installed with GPS enabled vehicle tracking system.

Disposal of SWM at present:
At present all the garbage thus collected from the city is disposed in open in two Dump yards by way of landfill without proper processing.There is some facility for processing of garbage at Debendra Chandra Nagar Dump yard but it is not so scientific and sufficient.Hence most of the garbage is dumped without processing.Work for Rs.16.50 Crore, 250 Tons per day solid waste processing plant has already started at Debendra Chandra Nagar Dump yard.

Municipal Solid Waste:
As per the MSW Rules-2000, Municipal Solid Waste is a trash/garbage that is discarded on day-to-day basis in a human settlement and includes commercial and residential waste generated in a Municipal or notified areas in either solid or semisolid form excluding industrial hazardous wastes but including treated biomedical waste.According to Agartala Municipal Corporation approximate daily total daily solid waste generation is 250 MT/Day.Following burning, water and nitrogen will be in a gaseous form.The amount of oxygen in the fuel contributes negatively to the amount of oxygen needed for combustion.The ash is not a part of the burning process.After burning, nitrogen and water are discovered in gaseous form.The process of combustion is not aided by the ash.The oxygen required for burning is negatively impacted by the oxygen present in the fuel.The following equations provide the theoretical reaction of combustion formulas of the combustible components of municipal solid waste. C+

Calculation of combustion air amount:
NO2 reacts with O2 at about 1200c and above from NOx.So, here the fuel temperature is assumed as 1150c.So N2 reacts is not considered here.Taking into account the combustion reaction in theory for this MSW analysis is -

Equivalent evaporation of boiler-
Equivalent evaporation is an important factor while determining the performance of the boiler.The amount of water evaporation at 100°C and dry saturated steam at 100°C at normal pressure.The value of latent heat is taken as 2257 Kj/Kg.The equitant evaporation of boiler, E= mr (αs-αw)/ 2257 Where, mr = ms/ msw = 12373.2/3600= 3.437 Kg/hr (αs-αw) /2257 is a factor of evaporation and its value is always greater than 1. E=3.437(3248.7-194.49)/2257=4.65 Kg of steam/ Kg of fuel.

Conclusion:
For the purpose of producing electricity, a small-scale steam boiler using combustible solid waste as fuel is thermally analysed.On the basis of the design parameters, energy utilization relations are produced and examined.The analysis's findings indicate that the amount of moisture in the flammable solid waste affects the solid waste's calorific value, and the quantity of solid waste burned affects how much steam is produced.However, the study conducted in this paper employed a calorific value of 17.49MJ/kg that was derived at a moisture content of 10%.This showed that burning 3.6 tons of solid trash per hour could produce roughly 3.437 kg/s of steam at 20 bar and 400°C.About 1.4MW of electrical power was calculated using the created steam, which can be used to generate electricity.

5. 0 5 . 2
Result and Discussion: 5.1 Calculation of WTE plant-These solid wastes, which have around 54.5 MT of open space in the WTE plant, have the potential to produce 1.4 MW of power daily.If they are burned in this way, they could help with the nation's efforts to create aesthetically pleasing environments.The electricity produced would significantly increase Agartala's economic activity, lessen the amount of time that electricity is unavailable, and supplement the current grid electricity.This amount of electricity would go a long way towards meeting the city of Agartala's electricity needs.The use of solid waste in this way would improve the cleanliness of city roads.The thermal evaluation of a steam boiler using solid waste as fuel is shown in this computation.We know that, Af = Furnace area towards cross-section (m 2 ) Cpfg = Specific heat capacity (flue gas) (kJ/kgK) CVsw = Waste calorific value (kJ/kg) ṁsw = Mass flow waste (kg/s) ṁair = Flow of air mass (kg/s) ṁs = Mass flow rate of steam (kg/s) Pe = Power (kW) P = Pressure of condenser (bar) Qf = Heat solid waste (released) (kW) Qs = Heat of (absorbed) steam (kW) T = Temperature (K) Wt = Work of turbine (kJ/kg) Wp = Work of pump (kJ/kg) αs = Steam enthalpy (kJ/kgK) α w = Water enthalpy kJ/kgK) nti = Isentropic efficiency of turbine (%kg) np = Isentropic efficiency of pump(%) ngen = Efficiency of generator (%) ntm = Mechanical efficiency of turbine shaft (%) nb = Thermal efficiency of boiler (%) air Combustion analysis of municipal solid waste [MSW]: Municipal Solid Waste Contains the important elements C kg of carbon[C], H kg of Hydrogen [H2], O kg of oxygen[O2], N kg of Nitrogen [N2], S kg of sulphur [S], M kg of moisture, a kg of ash.C+H2+O2+N2+S+m+a = 1kg of fuel (MSW).