The outbreak of coronavirus diseases (COVID-19) receives much attention globally. On January 30, 2020, WHO has stated it was a global health emergency. The Indonesian Government requiring that all work from home and restricting access to activities outside the home. In the Bali Province, it has had a positive impact on the environment, especially for the amount of waste generation and emissions. The main objectives of this study were to analyse solid waste generation and to provide a review of issues in environmental impact during and before the pandemic of COVID-19 in Bali Province. LCA technique has been used extensively to evaluate the environmental performance of several municipal solid waste management technologies. An LCA study consists of four stages, such as goal and scope, life cycle inventory, life cycle impact analysis, and interpretation. The degraded organic carbon (DOC) value before the pandemic was 0.121 while after the pandemic the DOC reduced to 0.058. Moreover, methane and carbon dioxide production from waste generation per day was counted in this study. The total global warming potential from waste generation has been drastically reduced from 1,859.6 kg CO 2eq /day to 420.8 kg CO 2eq /day.

The purpose of this research is to investigate wastewater treatment with ozone pretreatment and post-treatment integrated with Moving Bed Biofilm Reactor (MBBR). Ozonation as a pre-treatment served to increase the Biochemical Oxygen Demand (BOD)/Chemical Oxygen Demand (COD) ratio while as a post-treatment to remove the remaining organic residues. Ozone doses were 1 mg/min, 4 mg/min, 20 mg/min, and 40 mg/min. In the pre-treatment, ozone produced a BOD/COD value of 0.68. The MBBR process had a COD and color removal efficiency of 68.89% and 67%, respectively. In the MBBR process without ozone pre-treatment, the efficiency of COD and color removal were 79.31% and 64.7%, respectively. The effluent treatment results from MBBR were then processed with ozone and showed the highest COD and color removal results of 76.8% and 99%, respectively. In this study, the processing with ozone as post-treatment was better than the pre-treatment.

The purpose of this research was to process a mixture of paper waste and garden waste based on material flow analysis and to analyze its parameters based on water content, ash content, heating value, along with Thermogravimetry Analysis (TGA)/Derivative Thermogravimetry (DTG). The garden waste treatment process consists of shredding, drying with a rotary dryer, separator, and then shaving with a hammer mill. Paper waste only needs a shredder process. Then, the mixing process and pelletizing of paper waste as well as garden waste are carried out according to the variation (w/w) 100% paper (K100), 75% paper (K75), 50% paper (K50), 25% paper (K25), and 100% garden waste (K0). The water content ranged from 5.8 to 15.25%. From K0 to K100 samples, the ash content increased from 4.54 to 9.85%. A correlation of 0.9047 was found from samples K0 to K100. There was a correlation between increasing calorific value along with the mixture with paper waste. The caloric value in K0 to K100 increased from 13.11 to 19.03 MJ/kg. The TGA/DTG analysis reduced mass due to water evaporation, devolatilization, and carbonization processes.

The byproducts of anaerobic processes at municipal solid waste landfills are leachates and gas emissions. One of the landfills operating in the coastal area of Bali Island is the Suwung landfill. The objectives of this research is to identify the water quality index (WQI) and hydrogen sulfide (H 2 S) parameters, as well as the health complaints by the local community around the Suwung landfill. A total of 12 samples were taken from wells, and surface and coastal water bodies. The parameters measured in this study are TSS, DO, COD, BOD, and NO 3 -N. The comparison of the parameters were in accordance with PP No. 82 of 2001 for the second-class water quality standards. Each sample for the TSS and DO parameters meets only eight and five quality standards, respectively. Meanwhile the COD parameters are only met by one sample. For the BOD, all samples did not meet the second-class water quality standards. The WQI analysis showed that seven samples were slightly polluted and two samples were polluted moderately. The average WQI value per water quality is 4.12, which means that the water quality around the landfill is slightly polluted. The H 2 S parameters mention concentrations at four points do not meet air quality standards. Respondents felt uncomfortable with the odour caused by the H 2 S. The future implication of this study is to know the indications of public health conditions.

The coronavirus disease 2019 (COVID-19) shifts the characteristics of municipal waste. This paper aims to provide an overview of trends, impacts, and management during the COVID-19 pandemic globally. The increase in the generation of plastic waste and infectious waste is a new challenge during the COVID-19 pandemic. It was found that the emergence of plastic waste due to the consumption of food delivery becomes an issue in several countries. Despite the increment of plastic waste generation, the mass layoffs contributed to the decrease in the total urban waste generation in general. In addition to plastic waste, a surge of infectious waste from health facilities and household waste originating from residents infected with the SARS-COV-2 virus was observed. This infectious wastewater potentially leads to environmental disturbances to the rivers and oceans. To tackle global environmental concerns, sustainable waste management is required especially in the development of biodegradable personal protective equipment.

The generation of polyethylene terephthalate (PET) plastic and garden waste must be recycled to support the circular economy. An alternative way to reduce the plastics waste is to reduce this waste by converting it into energy such as Refused Derived Fuel (RDF) as an alternative for processing waste. Substitution of plastic and garden waste is an opportunity to be analyzed. Hence, This study aimed to investigate the potential for converting material substitution from PET and garden waste into RDF. The RDF characterized test method was carried out by proximate, water content, ash content, and analysis. At the same time, the calorific value. was tested by bomb calorimetry. Substitution of the mixture of plastic and garden waste affects each parameter of RDF pellet quality including water, ash, and caloric value (sig.< 0.05). The increase of plastic waste in pellets consistently increases the calorific value of RDF from 18.94 until 25.04 MJ/kg. The RDF pellet water and ash content also invariably affect the rate of increase in the calorific value of RDF in the multilinearity model (sig.<0.05; R2 is 0.935). The thermal stability of the pellets occurred at a temperature of 5000C decomposition of hemicellulose, cellulose, and lignin in mixed garden waste with plastic in RDF pellets. The decrease in the decomposition of PET into terephthalic acid monomer from the thermal stability of raw materials and waste PET plastic pellets occurs at a temperature of 4500˚C. This potential finding can be used as a basis for consideration in regions or countries that have the generation of garden waste and plastic, especially the type of PET to be used as an environmentally friendly fuel.

Highlight Research:The potential calorific value of marine debris obtained from calculating the total waste is 12.05 MJ/kg, which still falls within the incinerator application's standard criteria. AbstractMarine debris, a global environmental issue today, is a major threat to Bali’s seas which are famous for its natural beauty and aggravated by the spread of COVID-19 pandemic. This study aimed to determine the characteristics of marine debris in Bali Island, especially in the southern region and to analyze the feasibility of incineration as one of the waste treatment processes. This research was conducted by utilizing secondary data and literature reviews from related previous studies. Water content and caloric value were measured directly using the ASTM E 790-15 and ASTM D 5865-11a standards. Marine debris generation from 2013 to 2019 tends to decrease from 1.22 kg/km.day to 0.46 kg/km.day. Organic waste (59.4%) comprised the largest marine debris followed by plastic waste (13.4%) and diapers (11.9%). Thermal technology such as incineration can be introduced to treat marine debris. The standard application of incinerator technology is moisture content and caloric value. The water content of marine debris is reportedly 54.56%, therefore, further preliminary processing is needed, especially for waste with high moisture content, such as diapers and organic waste. The potential calorific value of marine debris during the COVID-19 pandemic obtained from calculating the total waste was 12.05 MJ/kg which still did not meet the incinerator application's standard criteria.

The generation of municipal solid waste (MSW) in Bali has various environmental impacts. One of the updates on sustainable waste processing is the RDF treatment plant processing. Before carrying out the processing, MSW characterization is needed because each region has a diverse composition. The processing of MSW into RDF provides benefits for achieving MSW reduction targets, renewable energy use, and the reduction of greenhouse gas (GHG) emissions. For this reason, this study was conducted to determine the potential of MSW in Bali as an alternative to renewable fuel and its potential to reduce GHG. MSW's potential calorific value as a raw material for RDF in Bali can reach 9.58 - 17.71 MJ/kg. The implementation of processing waste into RDF in pellets has shown a calorific value of ± 3904 - 4945 kkcal/kg. Implementing MSW processing into RDF in Bali can reduce GHG by 178 - 330 times compared to open dumping.