Recycling Potential and Processing Technology of Plastic Waste in Indonesia’s Metropolitan City (Case Study: Bandung City, West Java, Indonesia)

After organic waste, plastic became a significant issue in Indonesia. The government of Bandung City has started a number of programs to address the waste issue. However, there are still numerous obstacles to overcome, particularly in terms of finding ways to utilize waste instead of sending it to a landfill. The goal of this study was to ascertain the potential of plastic waste in Bandung that had been sent to a landfill. The study found that 98% of the total waste in Bandung was already being collected. The majority of it (83%) was going to a landfill. Total mixed transported to Sarimukti landfill was around 1,150 TPD, or 0.46 kg-e/person/day. Food waste made up the biggest percentage (35% dry season and 47% wet season, respectively). Approximately 129.940 tons of plastics, with a total composition of 32% for dry season and 30% for wet season being dumped in landfill consisting recyclable high value plastic of 8,383 TPD (6,45%), non-recyclable low value plastic of 98,502 tons (75,8%), and nappies of 23,054 tons (17,7%). Due to the limitation of recycling technology to treat these wastes, plastic in landfill were mainly composed of low value plastic and diaper.


Introduction
Similar to other developing countries, Indonesia's population growth have a negative impact on sanitary standards in the majority of its main cities.The improper management of municipal solid waste (MSW), a rising concern in metropolitan areas, is currently the most prevalent of all these issues.[1].The majority of the waste generated in Indonesia is organic waste.However, as a result of the community's changing lifestyle, there has been a huge increase in the usage of plastic, which became a major problem after organic waste [2,3].
In addition to serving as the provincial capital of West Java, Bandung is the largest metropolitan area in that province and the third-largest in all of Indonesia.Only 11.83% of the plastic waste on Java Island has been collected by upstream actors.While, 88.17% of plastic waste is either not collected and treated properl, which can pollute the environment, or it is sent straight to landfills without being processed in the recycling stream [4].
Bandung city's government has initiates several program to tackle waste problem especially to reduce waste transported to landfill such as Kang PISMAN.KangPisMan Movement an abbreviation of Reduce, Separate, and Utilize, one of the effort that goes directly at the source to valorise waste more.However, these efforts still facing many challenges.The purpose of this study was to determine the potential of plastic waste generated from Bandung city that has not been utilized by the upstream player and transported to the landfill.

Background of Study Area
Bandung city is located at 6 o 55' South Latitude and 107 o 36' East Longitude with 16,729.65 Ha area and 2,507,888 inhabitants in 2019 [5].Administratively, the City of Bandung is surrounded by a number of other Regencies/Cities, including: 1. Bandung Regency and West Bandung Regency; 2. The City of Cimahi; 3. Bandung Regency; and 4. Bandung Regency to the south.
Over the past ten years, Bandung's population has grown by an average of 0.21%.In addition, the GDP of the city of Bandung has grown by an average of 5.9% , increasing waste generation and necessitating the need for more sustainable waste management.

Methodology
This study was conducted in several stages, those are: a. Apparent specific gravity (ASG) of mix waste and each category of waste from the truck were measured.The composition waste measured using conical quartering method with the help of excavator.The quadrant methods was done several times until the one of the four segment was 250 kg of mixed waste.After its weight and volume had been measured then it was segregated by 9 different types, for its weight and volume to be measured separately, namely:  Others.For waste characterizations, the sample from each composition were taken according to the composition (%wet-weight) from the total weight and was stored in zip lock to maintain its characteristics and delivered to the laboratory.The characteristics that have been measured are:  Water content % of wet weight (%WW), examined using ASTM D2216-98 method, the number of sample was 12;  Ash content %of dry weight (%DW), examined using ASTM D2216-98 method, the number of sample was 12;  Volatile content %DW, examined using ASTM D2216-98 method, the number of sample was 12;  Calorific value (calories/gram of dry weight (cal/gr DW), the number of sample was 12;  Ultimate analysis, examined using ASTM D2216-98 method, the number of sample was 2.

Result 4.1 Waste management in Bandung City
As shown in Figure 1., 98% of total waste generated in Bandung city was already being managed.Most of it (83%) was being transported to landfill, and only 15% was processed in the city through waste bank (10,59%) and other waste reduction (4,41%) such as being collected by the informal sector and managed and reduce in MRF facility [6].

Figure 1. Waste flow in Bandung city in 2019
It can be seen from Figure 2. Waste generated in Bandung city some of it still not collected and will contaminated the environment.The other will be collected and went straight to the landfill or being managed in MRF facilities or transfer station, where valuable waste sorted out by formal or informal sector and the residue will go the landfill.A very little proportion of waste were also collected separately.This usually happens when the household sorted their valuable waste for the waste bank to get incentives or waste being hand pick by informal sector usually the value of waste played a very important part in this scheme.Plastic waste that is considered high value were PET, PP, Rigid HDPE, rigid LDPE because the price was higher than low value such as plastic bags, other flexibles multilayers, and nappies, that the price is not worth the time to sort it out and some even didn't have no value at all.

4
It is in line with other study that mention, that PP rigid, PET, HDPE film, HDPE rigid, and PP film are the five materials that has been colleced the most for recycling [7].,that the highest composition of solid waste transported to landfill from Bandung city was food waste both in dry season and wet season (35% and 47%).Where the composition for plastics (high value, low value and nappies) in dry season and wet season were 32% and 30%.It was dominated by non-recyclable/ low-value plastic with 24% and 23%.In wet season the composition of food waste was slightly higher, one of the reason was due to the increase of other waste such as yard waste from 6% (dry season) to 18% (wet season).This was because the rain helped drop the leaves on the trees on wet season.The other reason might be that other type of waste was absorbing more water in wet season compare to dry season.Further research should be conducted to compare water content of each categories of waste in dry and wet season.Therefore, plastic waste transported from Bandung city to Sarimukti landfill in 2019 was approximately 129.940 tones, with recyclable high value plastic 8,383 TPD (6,45%), non-recyclable low value plastic 98,502 tones (75,8%) and nappies 23,054 tones (17,7%).Most of plastic being transported to the landfill site was low value plastic that has not been utilized by upstream player because of its value that was affected by the technology available to process the waste.Recycling is limited to a certain kind of plastic.Due to technological limitations, some plastics, such as multilayer plastics, are not commonly recycled (the process is not yet commercially viable) [8].To the best of our knowledge, most of plastic waste from Bandung city being recycled mechanically and most of it processed high value plastic.Due to the difficulty of some plastic waste to be recycled mechanically might require the development of alternative recycling technology.This might be different in other cities of Indonesia due to the fact that Bandung city was one of the recycling hub in Indonesia.For the cities far from the recycling hub, the value of recyclable-high value plastic such as PET bottle, PP cup and other type of hard plastic was still very low due to the unavailability of the market nearby or the cost of transportation to the recycling hub is still very expensive making it non-profitable to be recovered.
Mechanical recycling that most widely used in Indonesia still has many shorcoming.Beside it can not process all type of plastic, most of recycle player in Indonesia was informal sector and did not have a proper waste management system especially for waste water.Adding a proper waste management system will add the cost to recycling business and it might make it less profitable especially for small player.Thus, only several of big recycling player that have a proper waste management system The majority of alternative recycling techniques utilize both thermal (incinerators, pyrolysis, waste paper and plastic fuel, and combustion of plastic in cement kilns) and chemical (gasification, blast furnaces, and coke ovens) processes [9,10].There are particular difficulties with thermal recycling.For instance The community has rejected incinerators frequently, especially in developing countries.A number of causes have contributed to incinerator failure, including the following: (1) Inability to pay processing fees; (2) Inability to maintain and replace reactor components; (3) Personnel shortages for operational and managerial functions; (4) Characteristics and volume of mixed waste; (5) Poor management; and (6) Inadequate institutional frameworks [11] As shown in Table 1.Bandung city mixed waste characterization has a high water content and a low calorific value.High water content makes thermal processing more energy intensive, necessitates longer drying times, and lowers temperature, which leads to partial conversion.These factors reduce the effectiveness of the method [12].Pre-treatment is required in order to process waste from Bandung City thermally but further study for plastic waste characterizations will be needed to determine other alternative technologies to process plastic such as chemical recycling.In order to show the environmental effects of mechanical recycling, chemical recycling, incineration, and landfilling, life cycle assessment (LCA) studies for plastic recycling technologies have been reviewed.Without taking power credits into account, the highest GHG emissions is from incineration vary from 1.8 to 3 kg CO2 equivalent per kg of plastic waste.After accounting for the electricity credit, the CO2 equivalent per kg of plastic waste is around 1.4 kg.Chemical recycling has a high potential for acidity.It becomes lower when the amount of plastic lost due to landfill or incineration is taken into account.For air pollution and resource depletion aspect has the lowest air emission and the amount of resource consumption of mechanical recycling is negative.However, the challenges are mechanical recycling can only be used to process a very small category of plastics.Although landfills emit low air pollution, they can pollute groundwater and soil.[13].

Recommendation for plastic waste management in Bandung city
From this study, these are several recommendation to improve plastic waste management in Bandung city: Reduce and substitute plastic usage especially for low value plastic.Some plastics were hard to recycle especially low value plastic.Therefore, there is a need to reduce plastic waste generation to prevent it harming the environment.Low value consists value plastic consist of some single-used plastic such as plastic bag, plastic wrap.Reducing single-used plastic will reduce low value plastic ending up in landfill Improve waste segregation.Bandung city mixed waste has a high moisture content.a high level of moisture Disadvantages about MSW include difficulties in recovering recyclable materials, increases in leachate, and a decrease in the net calorific value, make it unsuitable for thermal processing [14].Create an environmentally sound recycling ecosystem.Majority of recycling technology being used in Indonesia is mechanical recycling.Although mechanical recycling has less environmental impact compare to other technologies.In practice, many recycling practices in Indonesia do not pay attention to environmental sustainability.One example is the absence of wastewater treatment.It can be done by enforce monitoring for the recycling plant and create incentive scheme to support recycling industry to pay more attention to environmental sustainability.Develop technology to recycle low value plastic.Further studies might be needed to best treat plastic ending up in Bandung city landfill.

Conclusion
Total mixed waste transported to Sarimukti landfill from Bandung city was approximately 1,150 TPD or 2,500 m 3 /day equal to 0.46 kg-e/person/day 0.99 L-e/person/day.The highest composition of solid waste transported to landfill from Bandung city was food waste (35% and 47% dry season and wet season respectively).Where the composition for plastics (high value, low value and nappies) in dry season and wet season were 32% and 30%.Plastic waste transported from Bandung city to Sarimukti landfill in 2019 was approximately 129.940 tones, with recyclable high value plastic 8,383 TPD (6,45%), non-recyclable low value plastic 98,502 tones (75,8%) and nappies 23,054 tones (17,7%).It is dominated by low value plastic and nappies because of the limitation of recycling technologies to process those waste.

Figure 2 ,
Figure 2, Plastic waste flow in Bandung city 4.2 Waste generation and composition in Bandung City Waste generation and composition data below was waste transported to Sarimukti landfill, it would be different with waste data from the source or transfer station due to some recovery activities and leakage that might happen before it reached the landfill.Data collected from January 2017 to July 2019 from Sarimukti landfill, this facility received approximately 1,150 TPD or 2,500 m 3 /day of waste from Bandung City.Equal to 0.46 kg-e/person/day 0.99 L-e/person/day.Figure 3. shows waste received by Sarimukti landfill by month in different year.Waste transported to the landfill in Bandung city increase year by year.It's due to population growth and collection service growth.

Figure 3 .
shows waste received by Sarimukti landfill by month in different year.Waste transported to the landfill in Bandung city increase year by year.It's due to population growth and collection service growth.

Figure 3 .
Figure 3. Waste received by Sarimukti Landfill from January 2017 until April 2019 While for waste composition, it was shown in Figure 4. and Figure 5.,that the highest composition of solid waste transported to landfill from Bandung city was food waste both in dry season and wet season (35% and 47%).Where the composition for plastics (high value, low value and nappies) in dry season and wet season were 32% and 30%.It was dominated by non-recyclable/ low-value plastic with 24% and 23%.In wet season the composition of food waste was slightly higher, one of the reason was due to the increase of other waste such as yard waste from 6% (dry season) to 18% (wet season).This was because the rain helped drop the leaves on the trees on wet season.The other reason might be that other type of waste was absorbing more water in wet season compare to dry season.Further research should be conducted to compare water content of each categories of waste in dry and wet season.

Figure 4 .Figure 5 .
Figure 4.The Composition of waste received by Sarimukti landfill in dry season (% wet-weight)

Table 1 .
Bandung city waste characteristics