Technical and financial feasibility study of utilization municipal solid waste as Refuse-Derived Fuel (RDF) in Griyo Mulyo landfill

Griyo Mulyo landfill, the only final waste processing facility owned by Sidoarjo Regency, received a waste generation of 201,975 tons/year in 2022. Most of the municipal solid waste received by the Griyo Mulyo landfill was straightly dumped at the old landfill at 82.2% of total solid waste. Therefore, this research examined the potential for solid waste reduction at Griyo Mulyo final processing site with the Refuse-Derived Fuel (RDF) plant. In addition, an analysis of the financial feasibility of the RDF process and the environmental impact resulting from this process was also carried out. In this study, an analysis of the generation, composition, and density of solid waste received by Griyo Mulyo Landfill was carried out. From these data, the calculation of the mass balance of waste processing is carried out. The financial condition of RDF processing needs to be analyzed for financial feasibility, whether this activity is economically feasible. Some financial data required to calculate feasibility are sales of RDF products, RDF investment costs, and operational and maintenance costs. The result shows an average reduction in RDF raw material was 7.72% annually. The financial analysis on waste recovery to the RDF conversion system on Griyo Mulyo final processing site is feasible to be applied.


Introduction
Griyo Mulyo landfill located in Kupang Village, Jabon District of Sidoarjo Regency.As the only final processing site for municipal waste solids in the area, nearly 49% of total MSW generated by residents were disposed daily.For handling waste, Griyo Mulyo landfill adopted Emission Reduction in Cities-Solid Waste Management (ERIC-SWM), concept that oriented towards reducing the impact of soil, groundwater and air pollution caused by landfilling the municipal solids waste.From the total amount of waste received by Griyo Mulyo landfill per year 2022 of 201,975 tonss or 647.36 tonss per day, 0.19% were processed into compost, 3.87% were recycled and converted into RDF, 13.73% were dumped in the sanitary landfill and 82.2% directly landfilled in old landfills [1], which not suitable according to the requirements for urban scale landfills.It is necessary to carry out waste collection efforts by considering the resulting environmental impact.
One of the efforts to handle waste generation by Griyo Mulyo TPA is the process of converting waste into something that has beneficial value, Refuse-derived fuel (RDF).RDF is produced by separating the combustible fraction and the non-combustible fraction from the MSW mechanically.The results of waste separation are then adjusted in size to the standard required [2].Furthermore, drying is carried out to reduce the water content and increase the net calorific value of the waste.The characteristics of RDF raw materials are strongly influenced by proximate values, such as moisture content, ash content, and volatile solids content, and ultimate values such as carbon, hydrogen, oxygen, nitrogen and sulfur content.When compared to rice husk charcoal, RDF as a fuel has lower moisture content and volatile solids [3].Economically the price of RDF fluff as alternative fuel is competitive with the price of rice husk charcoal.The RDF production cost is IDR 272,000 per ton with a selling price of IDR 293,000 perton which is below the Willingness to pay limit of the cement industry [4].
This study aims to examine the feasibility of alternative fuel utilization from MSW using RDF method on technical, financial and environmental impact aspects.The technical feasibility analysis determine the waste reduction potential of Griyo Mulyo landfill referring to the projection of waste generation in the next ten years including the need for RDF processing infrastructure such as equipment, labor requirements and land requirements.The study of financial aspects carried out financial analysis on RDF waste processing.While the study of environmental impact aspects due to waste management studied is the evaluation of landfill quality based on the potential for waste reduction by RDF processing with an integrated risk-based approach (IRBA).

Location and time
This feasibility study was conducted at Griyo Mulyo, Sidoarjo Regency, East Java Province for about 5 months long from January until May of 2023.

Data collection
The data needed for analysis are divided into primary dan secondary data.The primary data were collected from field sampling at Griyo Mulyo site.Composition of waste was sampled based on Indonesian National Standars for "sampling and measurement of municipal waste generation" where 100 kg's of waste needed for analysis.The sampling method was carried out on a representative basis for the area of Sidoarjo Regency.Sidoarjo Regency has 4 regions namely West, East, North and South Sidoarjo.Garbage is taken specifically from transport trucks that carry waste from specific areas so that it does not mix with waste from different areas.MSW from each area was observed for 5 days to obtain a representative waste composition.Garbage sampling is carried out on trucks that enter the sorting plant.Analysis of waste density at the Jabon landfill was carried out by directly observing the incoming waste at the landfill.Each transport vehicle will be recorded its weight and volume, Based on the type of waste carrier that enters the Griyo Mulyo landfill.Laboratory test conducted to obtained the leachate quality being compare to the standard.

Data analysis
There are two aspects investigated in this study, (i) technical aspect and (ii) financial aspect.The first aspect mainly analyzing potential waste reduction by converting MSW into RDF based on waste composition, density and generation projected in 10 years of waste handling.Waste density is needed to analyze the feasibility of the operation of each equipment and other facilities, the amount of waste density depends on the collection and transport facilities used [5].Mass balance of MSW in Griyo Mulyo landfill also carried out to represent the handling of the waste.The second aspect aim to analyze feasibility of RDF production based on three aspects, net present value (NPV), internal rate of return (IRR) and benefit cost ratio (BCR).Formulation of NPV is as follows [6].
To complete the analysis, main data that required are total investment, production cost and revenue from producing RDF.Financial analysist calculated by three different scenarios as shown below (Table 1).

Composition, density and generation of waste
Figure 1 shows each waste fraction that handled by Griyo Mulyo dumpsite.The 100 kilograms of waste that has been weighed then grouped into 14 types of waste components, including various types of plastics such as LDPE, HDPE, PET, PP and PS (Styrofoam).Other waste components include paper, fabric, glass, cardboard, rubber, aluminum, hard metal (iron), residue (food remnants and leaves) and other components.The results of the analysis of the composition of the waste that enters the Griyo Mulyo landfill form the basis for considering the need for waste processing facilities, especially refusederived fuel (RDF).Food remnants and garden waste are waste that is considered as residue in the sorting process at the Griyo Mulyo Landfill sorting zone.This waste will later become the raw material for RDF production.This waste has the highest percentage with an average share of 62.25% of the total waste that enters sorting zone.Table 2 shows the average amount of MSW that handled by landfill daily.Based on regional policy and strategy for municipal waste management [7] handling coverage of Griyo Mulyo dumpsite was 48,89% of total resident of Sidoarjo Regency.Therefore, the amount of waste generation can be calculated by dividing average amount of waste generation to the served resident.Approximately waste generated by resident of Sidoarjo regency are 0.66 kg/day/capita.Referring to the projected optimization of waste that is sorted at the Griyo Mulyo landfill, the annual need for sorting processing machines and RDF can be calculated.In a waste sorting system consists of 2 tools, namely a bag opener machine and a conveyor belt.Waste that has been removed from plastic bags will then be sorted manually by 36 sorters with the help of a belt conveyor.If a maximum sorting capacity of 105 tons/day is used, the projected sorting machine needed 8 units in 2033.Furthermore, 62% of the sorting results in the form of garden waste and food remnants is processed with an RDF processing device consisting of trommel screens, destoner machines, chopping machines and conveyors.Total RDF machine set and sorting machine needed as year 2033 shown in Table 4.

Mass balance analysis
Mass balance analysis is needed to determine the potential of waste to be used as raw material for RDF.
Based on the results of observations of waste generation for 8 days.it was found that the flow of waste in the processing carried out at the landfill.In general.waste entering the Griyo Mulyo landfill will be divided into 3 treatments.direct landfilled.sorted into recoverable materials or RDF materials and composted.Based on the analysis of calculations of the waste flow for 8 days presented in Tables 2. it was found that 91.77% of the total waste entered the dumpsite or 616 tons/day was immediately landfilled without being given any prior treatment.Meanwhile.only 8.1% was sorted and 0.13% was composted.Optimization of waste processing at the Griyo Mulyo Landfill.especially in the RDF sorting and processing process.is needed to reduce waste that is stockpiled in old landfills and sanitary landfills.
Optimization is carried out by aligning the capacities of recycling processing and RDF processing.

Volume reduction potential
Potential reduction of landfilled waste at Griyo Mulyo landfill by converting MSW into RDF can be seen in Figure 3.This reduction was planned within period of 10 years.Comparing the current RDF production of 9% or 105 tons/day to targeted capacity at 50% in 2033.resulting average 7.72% reduction of waste to be landfilled.As comparison from projection waste handled by dumpsite at year 2033 of

Capital investment
The cost of procuring a set of RDF machines with a capacity of 70 tons/day at the Griyo Mulyo landfill consists of the construction costs for the RDF processing machine itself and the need for heavy equipment in the form of a backhoe (Table 5).Machine needed for producing RDF are trommel screen for sorting smaller particles.crusher machine.destoner machine.conveyor belt for transporting materials between processes.plastic chopper and organic chopper.

Operational and maintenance cost
Operational and maintenance costs are estimated costs that must be incurred annually for the process of producing municipal solid waste into RDF.The series of RDF processing machines used at the Griyo Mulyo Landfill has a capacity of 5 tons/hour and consists of two production process shifts per day for 7 hours each.The operational cost of processing RDF at landfill consists of the salaries of production personnel.heavy equipment operators.administration.heavy equipment fuel and electricity consumption.The cost of maintaining RDF processing at landfill consists of maintenance costs for backhoe heavy equipment.RDF machine tools and wages for technicians [8].Total projection of production cost based on Optimization is presented below (Table 6).

Total revenue
Total revenue is calculated based on sales of recoverable waste and RDF products.The calculation of the estimated cost of estimated based price (HPT) for RDF per tons depends on the comparison of the calorific value of biomass and coal and the average price of coal for the last 3 months [9].The estimated cost of RDF when using the coal reference used by PLTU Paiton is IDR 495,445 /tons and Tanjung Awar-Awar IDR 544,230 /tons.Therefore average price of RDF based on references is IDR 514,837/tons (Table 7).

Financial feasibility based on NPV, IRR and BCR indicators.
NPV. BCR and IRR analysis is obtained from a comparison of the present value of the investment.operational.maintenance costs and income earned during the 10 years projection.This analysis was conducted to determine the financial feasibility of processing MSW into RDF at the Griyo Mulyo landfill.Among the scenario.the third one is the most profitable.Based on the analysis of RDF management using scenario 3. where there is an increase in RDF sorting and production capacity.NPV obtained from 10 years sales projection gets a profit of IDR 109 billion.The BCR (Benefit Cost Ratio) value of 1.69 indicates that RDF processing is profitable.To get the IRR value.the effective interest rate is calculated where the total NPV is 0 (Table 8).

Figure 1 .
Figure 1.Composition of MSW at Griyo Mulyo landfill.Waste density analysis was carried out to determine the density of waste transported in each transport vehicle that enters Griyo Mulyo landfill, Jabon.The amount of density is obtained from dividing the weight of the waste loaded by each vehicle by the volume of waste transported.The average density value of the 4 types of transport vehicles handled at Griyo Mulyo landfill is 476.58 kg/m 3 .Table2shows the average amount of MSW that handled by landfill daily.Based on regional policy and strategy for municipal waste management[7] handling coverage of Griyo Mulyo dumpsite was 48,89% of total resident of Sidoarjo Regency.Therefore, the amount of waste generation can be calculated by dividing average amount of waste generation to the served resident.Approximately waste generated by resident of Sidoarjo regency are 0.66 kg/day/capita.

Figure 2
shows optimized mass balance of waste handling in Griyo Mulyo landfill.Approximately 75% of the waste input are sorted into recoverable waste and RDF material.a) Existing waste handling b) Optimization waste handling

Figure 2 .
Figure 2. Mass balance of existing and optimization waste handling.

Figure 3 .
Figure 3. Potential waste to be landfilled with RDF (blue) and exisiting (red).

Table 2 .
Average waste generation at Griyo Mulyo Landfill.3.2.Solid waste handling optimizationThe target for handling waste as stated in JAKSTRADA in 2023 is 50% of the total waste generation in Sidoarjo Regency.The amount of waste reduction includes limiting waste generation, waste recycling and waste reuse targeted at 27%.Meanwhile, 23% of waste is not managed.Waste handling increases 10% every year until the percentage of handling by landfill is reached by 70% and a reduction of 30% in 2025.Projections of waste generation generated by the people of Sidoarjo Regency until 2033 are as shown in Table3.

Table 4 .
Sorting and RDF sets required.
/day. if current condition applied amount of waste to be landfilled are 891 tons/day.Whereas based on optimaziton landfilled waste only a number of 104 tons/day.

Table 5 .
Total capital investment.

Table 6 .
Total production cost.

Table 8 .
Financial feasibility of three scenarios.According to the technical feasibility density of the waste entering the Griyo Mulyo landfill is 476.58 kg/m 3 .Therefore average amount of waste entering the Griyo Mulyo landfill in 2023 is 671,185 kg/day or 1.408 m 3 /day.As much as 91.77% of waste goes to landfill without processing.While 8.1% of the total waste is segregated which produces recycled waste and RDF.Griyo Mulyo landfill in 2023 serves 48.89% of the people of Sidoarjo Regency.waste generation rate of 0.64 kg/capita/day is obtained.The potential for reducing waste that will be landfilled at Griyo Mulyo landfill by optimizing RDF processing and recycling is 7.72% per year.Based on financial analysis calculated by 3 scenarios of Optimization.producing MSW into RDF is feasible to be applied.All of the scenarios shows net present value above 0. and benefit cost ratio more than 1.