Proximate composition of household waste and applicability of waste management technologies by source separation in Hanoi, Vietnam

Abstract The organic fraction of municipal solid wastes in Southeast Asia, which has a high moisture content, accounts for a large proportion of total waste. Local governments need to pay adequate attention to the composition of wastes to determine alternative waste management technologies. This study proposed the use of a triangle diagram to describe changes in proximate composition and rates of successful source separation of municipal solid waste and to identify technical challenges about alternative waste management technologies such as incineration, composting, and refusederived fuel production based on physical and proximate composition analysis of household waste sampled in Hanoi, Vietnam, as a case study. The analysis indicated the effectiveness of different types of source separation as well as different levels of successful achievement of source separation as an adjustment mechanism for the proximate composition of waste. Proper categorization of wastes for source separation is necessary for the appropriate use of alternative waste management technologies. The results showed that, at a source separation rate of just greater than 0.52 in a threeway separation scheme, the waste separated as combustible waste would be suitable for incineration with energy recovery. Based on welldesigned scheme

J Mater Cycles Waste Manag (2016) 18:517–526 DOI 10.1007/s10163-014-0348-5 ORIGINAL ARTICLE Proximate composition of household waste and applicability of waste management technologies by source separation in Hanoi, Vietnam Kosuke Kawai • Luong Thi Mai Huong Masato Yamada • Masahiro Osako • Received: 25 January 2014 / Accepted: 21 December 2014 / Published online: January 2015 Ó Springer Japan 2014 Abstract The organic fraction of municipal solid wastes in Southeast Asia, which has a high moisture content, accounts for a large proportion of total waste Local governments need to pay adequate attention to the composition of wastes to determine alternative waste management technologies This study proposed the use of a triangle diagram to describe changes in proximate composition and rates of successful source separation of municipal solid waste and to identify technical challenges about alternative waste management technologies such as incineration, composting, and refuse-derived fuel production based on physical and proximate composition analysis of household waste sampled in Hanoi, Vietnam, as a case study The analysis indicated the effectiveness of different types of source separation as well as different levels of successful achievement of source separation as an adjustment mechanism for the proximate composition of waste Proper categorization of wastes for source separation is necessary for the appropriate use of alternative waste management technologies The results showed that, at a source separation rate of just greater than 0.52 in a three-way separation scheme, the waste separated as combustible waste would be suitable for incineration with energy recovery Based on well-designed schemes of K Kawai (&) Á M Yamada Á M Osako Center for Material Cycles and Waste Management Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan e-mail: kawai.kosuke@nies.go.jp L T M Huong Institute for Urban Environment and Industry of Vietnam, 56/221, De La Thanh, Dong Da, Hanoi, Vietnam source separation, alternative waste management technologies can be applied Keywords Household waste Á Source separation Á Waste management technology Á Proximate composition Á Developing country Introduction In Southeast Asia, municipal solid waste is usually collected without source separation or pre-treatment and transported directly to landfills or open dumping sites, most of which are rarely technically managed because of budget constraints [1] Heavy rainfall, combined with poor management of disposal sites, allows a great deal of untreated leachate to leak into the aquatic environment near the sites Moreover, poor municipal solid waste management results in methane emissions, which are generated in the process of biodegradation of organic waste in the tropical climate of Southeast Asia and have a greenhouse effect about 21 times greater than that of carbon dioxide Local governments in Southeast Asian countries have struggled to extend the lifespan of current disposal sites and to secure new ones as the amount of waste collected has increased dramatically because of rapid population and economic growth in urban areas Various life cycle assessment (LCA) models have evaluated the environmental performance of municipal solid waste management facilities and clarified the disadvantages of poorly managed landfills as compared with alternative waste management technologies [2, 3] Alternative waste management technologies such as incineration, composting and refuse-derived fuel (RDF) production can reduce the volume of municipal solid waste to be 123 518 disposed of at landfill sites Incineration can also generate electricity if the heating value of the wastes is sufficient, composting can produce organic fertilizers that can substitute for chemical fertilizers and RDF can substitute for natural resources consumed as fuel [4] With some exceptions such as the Phuket treatment facility in Thailand [5] and others in Singapore [6, 7], large-scale incineration facilities for municipal solid waste management are rare in Southeast Asia, although some major cities have recently begun to consider installing them [8, 9] Composting or aerobic biological treatment has been applied at the community and neighborhood level as well as at the city level as a component of a mechanical biological treatment (MBT) system [10, 11] The Bangkok Metropolitan Administration in Thailand has also started producing RDF as a component of MBT [12] Local governments face many difficulties when replacing landfills with alternative waste management technologies because of technical constraints, and even if alternatives can be implemented, landfills cannot be entirely replaced because remaining residues will still need to be landfilled The organic fraction contains high moisture content and accounts for a large proportion of municipal solid waste in Southeast Asia [13–16] The high moisture content may encumber the operation of waste management technologies and require additional fuel and materials or pre-treatment processing [17] Previous LCA studies [5, 18–20] that have evaluated the environmental performance of municipal solid waste management systems employing alternative waste management technologies in Southeast Asia assumed that the alternative technologies were applicable, without any consideration of basic qualitative parameters for operation of technologies, for example, the proximate composition of the waste (moisture, volatile, and ash contents) Local governments in Southeast Asia need to pay adequate attention to the characteristics of their municipal solid waste to determine whether alternative waste management technologies are appropriate for the waste This study proposed the use of a triangle diagram to confirm whether the current proximate composition of municipal solid waste would be suitable for incineration, composting and RDF production by using physical and proximate composition analyses of household waste in Hanoi, Vietnam, as a case study This study also identified technical challenges of municipal solid waste management, showing the ranges of change in proximate composition on triangle diagrams as related to varying levels of successful achievement of three types of source separation of household waste Note that this study did not account for other relevant aspects, such as the chemical properties of waste and financial feasibility, which are also important in discussions regarding the adoption of new waste management systems in developing countries 123 J Mater Cycles Waste Manag (2016) 18:517–526 Materials and methods Physical and proximate composition analysis Household waste was sampled from four urban districts (Ba Dinh, Hoan Kiem, Dong Da, and Hai Ba Trung districts; Fig 1) in Hanoi We selected eight collection points of municipal solid waste from the four districts (two per district) on a random basis and requested the cooperation of community leaders and municipal solid waste collection workers in sampling waste from households Discarded household waste is collected daily in the evening in Hanoi, and we sampled household waste from the eight collection points every evening from 17:00 to 19:00 for days from 25 November to December 2011 except for December, when sampling was not conducted because of rain A total of 828 kg of waste was collected from 339 households (1252 residents), which was equivalent to approximately 0.12 % of the population in the four districts (1,055,800 residents [21]) Each day, the samples were immediately transported to a roofed area at the Cau Dien Composting Site located 10 km west of the center of Hanoi city Ideally, the physical composition analysis should be conducted promptly after sampling because the moisture content of wet wastes such as food waste is highly likely to leach into other types of wastes such as paper However, waste samples were stored for a half day because of practical limitations involved with doing the work at night The physical composition analysis was therefore conducted every morning from 8:00 to 10:00 on the previous day’s Nam Son landfill site Hoan Kiem Urban districts Ba Dinh Cau Dien composting site Dong Da Hai Ba Trung Hanoi 10 km Vietnam Fig Map of Hanoi, Vietnam J Mater Cycles Waste Manag (2016) 18:517–526 collected samples Six workers manually sorted all waste samples into 16 physical categories of waste: paper, plastic, glass, and metals as salable waste; and food, garden, paper, plastic, wood, textiles, rubber and leather, glass, metals, coal ash, ceramics, and other materials as unsalable waste Coal ash is the residue from burning coal briquettes for cooking This is a commonly used fuel source in Hanoi [22], but it is not a common characteristic of household waste in other Southeast Asian countries In some countries, coal ash is classified as a hazardous waste because of its relatively high heavy metal content Paper, plastics, glass, and metals are usually regarded to be salable resources, but very wet or dirty paper products, broken glass, plastic bags, and greasy aluminum foil were categorized as unsalable The proportion of salable waste to total waste in the samples was probably lower than the actual proportion because only waste that was certain to have a market value was regarded as salable in this study, and some salable waste may have been miscategorized as unsalable After the waste samples had been sorted into the 16 categories, they were weighed with a digital scale (CJ8200, Shinko Denshi Co., Ltd., Tokyo, Japan) with a minimum reading of 0.1 g The weights were verified to detect data entry errors by comparing the total weight before and after sorting Proximate composition data (data on moisture, volatile, and ash contents) of all categories of waste samples were obtained twice during the 8-day sampling period, and the average values of each waste category served as a basis of estimation of changes in proximate composition of household waste after source separation The following procedure was used to analyze proximate composition Samples of each of the 15 waste types (excluding ‘‘other’’) were reduced to approximately 100 g each by the conical quartering method The reduced sub-samples were dried in a laboratory drier at 85 °C for days to measure the moisture content Although an authorized method in Japan [23] states that samples should be dried at 105 °C for moisture content measurements, we used 85 °C to prevent the plastic sample from melting The dried samples were burned at 800 °C for h in an incinerator to measure volatile (i.e., combustible) and ash contents We did not estimate the volatile content of glass, metals, and ceramics, which were categorized as non-combustible The average proximate composition of all 11 unsalable waste samples was substituted for that of the ‘‘other’’ category Moisture, volatile, and ash contents of household waste were calculated with Eqs 1, and 3, respectively X Wi  Mi WH ẳ 1ị 100 X Vi M i 2ị VH ẳ 100 519 AH ẳ X Ai M i 100 ð3Þ ; where WH is moisture content of household waste (%), Wi is moisture content of waste category i (%), Mi is physical composition of waste category i (%), VH is volatile content of household waste (%), Vi is volatile content of waste category i (%), AH is ash content of household waste (%), and Ai is ash content of waste category i (%) We detected a notable transfer of water from food waste to unsalable paper and plastic waste because it took at least a half day to initiate the analysis of the moisture content of the wastes after sampling To simulate the original moisture content of the wastes before the water transfer resulting from the delay, we adjusted the moisture content of unsalable paper and plastic waste to match those of salable ones, which were found to contain much less moisture The moisture content of food waste was then correspondingly increased The ratios between volatile and ash content in food and unsalable paper and plastic waste were maintained at the same values before and after the adjustment Some parameters include uncertainties as a result of various factors The effects caused by these uncertainties should be considered in our analysis In particular, moisture content in household waste plays a significant role when determining the applicability of waste management technologies Therefore, in the presentation of results, uncertainty in moisture content was shown as a range when visualizing the ranges of change in proximate composition of household waste depending on achievement levels of source separation Uncertainty of moisture content of all waste categories ranged from -5 to % of the average measured value, and proximate composition based on the uncertainty was calculated with Eqs 4, 5, and 6, respectively: X Wi ặ U ị Mi WHU ẳ ; 4ị 100 X f100 Wi ặ U ịg Vi Mi VHU ẳ ; 5ị Vi ỵ Ai ị 100 AHU ẳ X f100 Wi ặ U ịg Ai Mi Vi ỵ Ai ị 100 ð6Þ ; where WHU is moisture content of household waste based on uncertainty (%), U is the uncertainty of moisture content for all waste categories, VHU is volatile content of household waste based on uncertainty (%), and AHU is ash content of household waste based on uncertainty (%) The uncertainty of moisture content changes at the same time for all categories of waste within a defined range (U 0:05) Scenarios and achievement rate of source separation Source separation of household waste is regarded as a fundamental policy of waste management in Japan Each 123 520 local government designs its own categories of source separation in line with local policies and conditions Municipalities have depended largely on incineration technology for municipal solid waste management; almost all municipalities have combustible waste (usually including food waste) as a category of source separation In addition to combustible waste, containers and packaging wastes such as cardboard, beverage bottles, and aluminum cans are also often collected separately Less commonly, some municipalities collect food waste separately for composting or anaerobic digestion Because categories of source separation in Japan vary from municipality to municipality, new residents may initially be confused at the sometimes complicated and unique categories of source separation In this study, we propose three source separation scenarios, all of which are designed to be easy to understand In scenario I, household waste was separated into two types: combustible waste for incineration or RDF production and non-combustible waste for landfilling In scenario II, household waste was also separated into two types: biodegradable waste for composting and non-biodegradable waste for incineration or landfilling In scenario III, household waste was separated into three types: combustible waste for incineration or RDF production, non-combustible waste for landfilling, and biodegradable waste for composting Because it would be almost impossible in practice for all people to perfectly separate their household waste, we defined the ‘‘achievement rate of source separation’’ as the proportion of the actual separation rate (x) When household waste is separated into two types (A and B; corresponding to scenarios I and II), some of the waste categorized as A will be appropriately separated as A (x), but some will be inappropriately separated as B (1 À x) (Fig 2) In scenarios I and II, the achievement rate was assumed to range from 0.5 to 1.0, and an achievement rate of 0.5 implies that sorting is random and that waste separated as A will be of the same quality as waste separated as B An achievement rate of 0.7 in scenario I, for example, represents the situation in which 0.7 of combustible waste by weight is appropriately separated as combustible waste, and the remaining 0.3 by weight is incorrectly included as non-combustible waste An achievement rate of 1.0 means that all household waste is perfectly separated When household waste is separated into three types (A, B, and C; corresponding to scenario III), we assumed that the rate of inappropriate separation was ð1 À xÞ Â 0:5 (Fig 3) In scenario III, the achievement rate was assumed to range from 0.33 to 1.0, and an achievement rate of 0.33 implies that sorting is random and that waste separated as A will be of the same quality as waste separated as B and C The achievement rates of source separation of waste 123 J Mater Cycles Waste Manag (2016) 18:517–526 Waste categorized as A Waste categorized as B Separated as A Separated as B Separated appropriately Separated inappropriately Fig Achievement rate of source separation (x) for two waste categories to be separated Waste categorized as A Separated as A Waste categorized as C Separated as B Separated as C Waste categorized as B Separated appropriately Separated inappropriately Fig Achievement rate of source separation (x) for three waste categories to be separated categorized as A, B, and C were set as a single parameter to simplify the case study Taking into account the uncertainty in the measurements of moisture content, the ranges of change in the proximate composition shown on the triangle diagrams in the results represent achievement rates ranging from 0.5 to 1.0 in scenarios I and II and from 0.33 to 1.0 in scenario III In Japan, almost all municipalities treat food and garden waste at incineration plants Food and garden waste were, therefore, categorized as combustible waste in scenario I following the waste management practice in Japan and as biodegradable waste in scenarios II and III (Table 1) Paper J Mater Cycles Waste Manag (2016) 18:517–526 521 Table Types and categories of household waste based on scenarios of source separation Scenario I Types Combustible Categories Food Garden Paper Plastic Wood Textiles Rubber and leather 4 4 4 Biodegradable Non-biodegradable 4 4 III Combustible 4 4 Ceramics 4 4 4 4 4 4 Other materials 4 Non-combustible Coal ash II Biodegradable Metals Non-combustible Glass 4 Included and wood waste were not categorized as biodegradable waste in scenarios II and III because of the much longer time period required for biodegradation as compared with food and garden waste Proximate composition boundaries and 12; 570\210  V: ð12Þ Equation 13 shows the moisture content boundary for truck unloading, moving heavy equipment, and covering soil during landfilling (Fig 8): ð13Þ W\85: Each waste management technology has application limits depending on the proximate composition of the particular type of waste [24] This study adopted the range limits of Tanaka et al [25] as follows Equation shows the ranges of volatile content and moisture content for the self-sustaining combustion of waste (Fig 4), and Eq shows the ranges of them for energy recovery by incineration (Fig 5): 3352\HL ¼ ð210  V Þ À ð25  W Þ; ð7Þ 6285\HL ¼ ð210  VÞ À ð25  WÞ ð8Þ Results and discussion Physical and proximate composition Food waste was the largest component of household waste, accounting for 57.3 % of total waste; it also had the highest moisture content (76.1 %; Table 2) The average moisture, volatile, and ash contents for the household waste collected were 57.7, 24.1, and 18.2 %, respectively Coal ash where HL is lower heating value (kJ kg-1), V is volatile content (%), and W is moisture content (%) Equation shows the range of the moisture content that allows sufficient oxygen and water supply for aerobic digestion for composting, and Eq 10 shows the relationship between moisture and volatile content that allows moisture to evaporate with aerobic metabolic heat (Fig 6): 50\W\70 100 80 60 ð9Þ 40 and 25  W\168  V  0:5: Equation 11 shows the moisture content boundary for RDF production at which it is not necessary to install a pretreatment facility for drying waste, and Eq 12 shows the volatile content boundary at which waste is available as fuel above 12,570 kJ kg-1 of higher heating value (Fig 7) W\20 20 ð10Þ ð11Þ Application range of incineration 3352 < HL (kJ kg -1) Volatile (%) Fig Application range of incineration for varying sets of proximate composition HL is lower heating value The shaded area indicates the area, where the technology is feasible given the proximate conditions 123 522 J Mater Cycles Waste Manag (2016) 18:517–526 100 100 80 80 60 60 40 40 Application range of 20 incineration with energy recovery 6285 < HL (kJ kg -1) 20 Application range of RDF production Volatile (%) Volatile (%) Fig Application range of incineration with energy recovery for varying sets of proximate composition HL is lower heating value The shaded area indicates the area, where the technology is feasible given the proximate conditions Fig Application range of RDF production for varying sets of proximate composition The shaded area indicates the area where the technology is feasible given the proximate conditions 100 100 80 80 60 60 Application range of composting 40 40 Application range of landfilling 20 20 0 Volatile (%) Volatile (%) Fig Application range of composting for varying sets of proximate composition The shaded area indicates the area where the technology is feasible given the proximate conditions accounted for 11.3 % of household waste by weight and was categorized as non-combustible waste in consideration of its relatively low volatile content (6.7 %) and high ash content (81.1 %) This analysis indicated that the use of coal briquettes for cooking had a considerable effect on the physical and proximate composition of household waste in Hanoi However, coal briquettes are expected to be replaced in the near future by propane gas as living conditions improve In that case, a much smaller amount of coal ash would be generated by households The moisture content of paper and plastics sorted as unsalable waste exceeded 50 %, most likely because of transfer of moisture 123 Fig Application range of landfilling for varying sets of proximate composition The shaded area indicates the area where the technology is feasible given the proximate conditions content from food waste Salable waste accounted for only 3.6 % of the total, and the moisture content of the paper and plastics sorted as salable waste was much lower, less than 10 % in each case As stated previously, the actual proportion of salable waste may have been higher because the sorting criteria of physical composition analysis were very conservative Household hazardous wastes such as syringes, fluorescent lamps, and dry-cell batteries were observed during the physical composition analysis, but the proportion was very small and the items were included in the appropriate category (i.e., syringes, plastic; fluorescent lamps, glass; and dry-cell batteries, metal) J Mater Cycles Waste Manag (2016) 18:517–526 Table Physical and proximate composition of household waste sampled in Hanoi (%) Categories 523 Physical composition Proximate composition Moisture Volatile Ash 13.0 Salable Paper 0.8 8.3 78.7 Plastic 1.4 7.3 90.8 1.9 Glass 0.9 0.2 0.0 99.8 Metals 0.5 3.6 0.0 96.4 Unsalable Food 57.3 76.1 18.5 5.4 Garden 3.4 72.9 22.6 4.5 Paper 6.4 55.2 38.8 5.9 Plastic 8.2 53.4 42.1 4.5 Wood Textiles 1.0 1.9 27.2 13.5 65.3 84.2 7.5 2.4 Rubber and leather 0.2 3.2 81.5 15.2 Glass 0.6 0.6 0.0 99.4 Metals 0.1 8.2 0.0 91.8 Coal ash 11.3 12.3 6.7 81.1 Ceramics 0.7 0.5 0.0 99.5 Other materials 5.3 29.4 32.7 37.9 Table shows the adjusted proximate composition of food, unsalable paper, and plastic waste simulating the original composition before the transfer of water from food waste to the paper and plastic waste The moisture content of food waste increased from 76.1 to 88.0 % corresponding with the adjustment of the moisture contents of unsalable paper and plastic waste from 55.2 to 8.3 % and 53.4 to 7.3 %, respectively These adjusted values were utilized for estimating the changes in proximate composition of household waste in line with source separation achievement as discussed in the next section incineration plants with energy recovery and at RDF production plants Figure 10 shows the ranges of change in proximate composition of household waste according to achievement rate of source separation for scenario I (household waste was separated into combustible and non-combustible waste) Moisture and volatile content of the waste separated as combustible waste showed little change as the achievement rate increased, and the lower heating value of the combustible waste peaked at 3571–4774 kJ kg-1 when the achievement rate was set at 1.0 Source separation of 100 Scenarios and changes in proximate composition The lower heating value of household waste in Hanoi was estimated to be 3591 kJ kg-1 by Eq 7, which is barely greater than the level necessary for self-sustaining combustion (Fig 9) The high proportion of food waste with its high moisture content reduced the lower heating value Figure illustrates that additional drying would be necessary to manage current household waste in Hanoi at 80 60 40 20 Table Adjusted proximate composition of food, and unsalable paper and plastic waste (%) Categories Moisture Volatile Food 88.0 9.3 2.7 Paper 8.3 79.6 12.2 Plastic 7.3 83.7 9.0 Ash Volatile (%) Fig Current proximate composition of household waste in Hanoi (filled diamond) The solid lines inside the triangle diagram reflect the boundaries of respective waste management technologies 123 524 J Mater Cycles Waste Manag (2016) 18:517–526 100 100 1.0 80 80 1.0 0.5 60 0.5 60 0.5 0.5 40 40 20 20 1.0 1.0 0 Volatile (%) Volatile (%) Separated as combustible waste Separated as non-combustible waste Fig 10 Range of changes in proximate composition of household waste at various achievement rates of source separation in scenario I (shaded areas) The lines inside shaded areas reflect proximate composition at 0.1 intervals of achievement rates from 0.5 to 1.0 household waste with a high proportion of food and garden waste, as presented in scenario I, would not be effective in increasing the heating value of the waste Furthermore, this scenario suggests that food and garden waste, which have a high moisture content, should not be included in the waste to be incinerated given the current waste composition in Hanoi In addition, the volatile content of the coal ash prevents the volatile content of the waste separated as noncombustible waste from reaching zero The triangle diagram for scenario II (household waste was separated into biodegradable and non-biodegradable waste, Fig 11) shows that the applicability of incineration of the waste separated as non-biodegradable waste rises with increases in the achievement rate Because the moisture content of the waste separated as biodegradable waste increased as the achievement rate increased, it would be necessary to add water-conditioning agents such as rice husks and rice straw to the composting process to adjust the moisture content of the waste Fortunately, it would be relatively easy to secure these materials in Vietnam, which is a major producer of rice Although we categorized paper and wood waste as non-biodegradable waste in this study, they are actually biodegradable in the long term and absorb moisture, prevent odors under anaerobic conditions, and increase air circulation [4] To successfully apply incineration with energy recovery, the achievement rate needs to be greater than 0.74 for the waste separated as non-biodegradable waste The maximum lower heating value of the waste separated as non-biodegradable waste was 9600–9763 kJ kg-1 at an achievement rate of 1.0 Even with an achievement rate of 1.0, the volatile content of the 123 Separated as biodegradable waste Separated as non-biodegradable waste Fig 11 Range of changes in proximate composition of household waste at various achievement rates of source separation in scenario II (shaded areas) The lines inside shaded areas reflect proximate composition at 0.1 intervals of achievement rates from 0.5 to 1.0 100 1.0 80 0.5 60 0.5 0.5 40 20 1.0 1.0 Volatile (%) Separated as combustible waste Separated as non-combustible waste Separated as biodegradable waste Fig 12 Range of changes in proximate composition of household waste at various achievement rates of source separation in scenario III (shaded areas) The lines inside shaded areas reflect proximate composition at an achievement rate of 0.33 and at 0.1 intervals of achievement rates from 0.4 to 1.0 waste separated as non-biodegradable waste did not meet the criteria for RDF production Figure 12 shows the triangle diagram for scenario III (household waste was separated into combustible, noncombustible, and biodegradable waste) The ranges of change in the proximate composition of the waste separated as combustible waste were ideally distributed to be treated J Mater Cycles Waste Manag (2016) 18:517–526 with incineration At higher source separation rates, moisture content decreased and the amount of volatile matter increased To successfully apply incineration with energy recovery, the achievement rate needs to be just greater than 0.52 for the waste separated as combustible waste When the achievement rate exceeded 0.92, the waste separated as combustible waste could be applied for RDF production The maximum lower heating value of the waste separated as combustible waste was 14,498–14,729 kJ kg-1 at an achievement rate of 1.0 Conclusion This study analyzed the effect of source separation on changes in proximate composition of household waste in Hanoi, Vietnam, and on the applicability of alternative waste management technologies with triangle diagrams Proper categorization of wastes for source separation is necessary if alternative waste management technologies are to be used successfully The results showed that the two-way separation scheme categorizing household waste into biodegradable and non-biodegradable waste (scenario II) was more effective to apply for incineration with energy recovery than that of the scheme categorizing household waste into combustible and non-combustible waste (scenario I) At a source separation rate of just greater than 0.52 in the three-way separation scheme presented in scenario III, the waste separated as combustible waste would be suitable for incineration with energy recovery; moreover, the waste could be applied for RDF production with an achievement rate of greater than 0.92 Therefore, welldesigned source separation schemes should be an important component of alternative waste management technologies This study focused only on the proximate composition to evaluate the applicability of alternative waste management technologies to landfilling, but other aspects should also be studied to strengthen the utility of the analytical tool After composting and RDF production, the processed wastes will be sold and distributed as secondary resources To produce reliable and safe products, wastes input in the processes must meet chemical criteria, such as pH and concentration of heavy metals and chloride [26] Financial feasibility is especially important in discussions regarding the adoption of new waste management systems in developing countries The triangle diagram allows the visualization of the proximate composition of separated wastes and can contribute to decision-making to improve municipal solid waste management Any local government can apply this type of analysis if they have data on the physical and proximate composition of waste in their local areas Appropriate methods for continuously recording data on 525 the physical and proximate composition would make the use of the triangle diagram even more reliable Periodic sampling at regular intervals must be done carefully to be representative of local wastes and result in reliable composition data Historical data can aid in estimating a reasonable range of waste composition Local governments will not be able to implement successful source separation systems without the cooperation of their residents Although pilot-scale source separation systems have been attempted in Hangzhou in China [27], Hanoi in Vietnam [28] and Hatyai in Thailand [29], cityscale systems have rarely been established in developing countries Local governments in these countries have to develop effective strategies to involve residents in the source separation systems not simply by importing systems that have already been applied in developed countries, but by taking into consideration local factors such as customs, economic conditions, culture and religion Acknowledgments We sincerely thank Nguyen Huu Dung of the Institute for Urban Environment and Industry of Vietnam and all the staff of the International Cooperation Department, Hanoi Urban Environment Company for supporting this study We express our sincere and profound gratitude to the Environment Research and Technology Development Fund by the Ministry of the Environment, Government of Japan References Memon MA (2010) Integrated solid waste management based on the 3R approach J Mater Cycles Waste Manag 12:30–40 Cleary J (2009) Life cycle assessments of municipal solid waste management systems: a comparative analysis of selected peerreviewed literature Environ Int 35:1256–1266 Winkler J, Bilitewski B (2007) Comparative evaluation of life cycle assessment models for solid waste management Waste Manag 27:1021–1031 McDogall F, White P, Franke M, Hindle P (2001) Integrated solid waste management: a life cycle inventory, 2nd edn Blackwell Science, Oxford Liamsanguan C, Gheewala SH (2008) The holistic impact of integrated solid waste management on greenhouse gas emissions in Phuket J Clean Prod 16:1865–1871 Khoo HH, Lim TZ, Tan RBH (2010) Food waste conversion options in Singapore: environmental impacts based on an LCA perspective Sci Total Environ 408:1367–1373 Bai R, Sutanto M (2002) The practice and challenges of solid waste management in Singapore Waste Manag 22:557–567 Bangkok Metropolitan Administration (2012) Bangkok State of the environment 2010–2011 Bangkok Metropolitan Administration, Bangkok Kathirvale S, Yunus MNM, Sopian K, Samsuddin AH (2003) Energy potential from municipal solid waste in Malaysia Renew Energ 29:559–567 10 Pasang H, Moore GA, Sitorus G (2007) Neighbourhood-based waste management: a solution for solid waste problems in Jakarta, Indonesia Waste Manag 27:1924–1938 11 Muttamara S, Visvanathan C, Alwis KU (1994) Solid waste recycling and reuse in Bangkok Waste Manag Res 12:151–163 123 526 12 Nithikul J, Karthikeyan OP, Visvanathan C (2011) Reject management from a mechanical biological treatment plant in Bangkok, Thailand Resour Conserv Recy 55:417–422 13 Damanhuri E, Wahyu IM, Ramang R, Padmi T (2009) Evaluation of municipal solid waste flow in the Bandung metropolitan area, Indonesia J Mater Cycles Waste Manag 11:270–276 14 Shekdar AV (2009) Sustainable solid waste management: an integrated approach for Asian countries Waste Manag 29:1438–1448 15 Thanh NP, Matsui Y, Fujiwara T (2010) Household solid waste generation and characteristic in a Mekong Delta city, Vietnam J Environ Manag 91:2307–2321 16 Troschinetz AM, Mihelcic JR (2009) Sustainable recycling of municipal solid waste in developing countries Waste Manag 29:915–923 17 Wilson DC, Rodic L, Scheinberg A, Velis CA, Alabaster G (2012) Comparative analysis of solid waste management in 20 cities Waste Manag Res 30:237–254 18 Aye L, Widjaya ER (2006) Environmental and economic analyses of waste disposal options for traditional markets in Indonesia Waste Manag 26:1180–1191 19 Chaya W, Gheewala S (2007) Life cycle assessment of MSW-toenergy schemes in Thailand J Clean Prod 15:1463–1468 20 Gunamantha M, Sarto (2012) Life cycle assessment of municipal solid waste treatment to energy options: case study of Kartamantul region, Yogyakarta Renew Energ 41:277–284 123 J Mater Cycles Waste Manag (2016) 18:517–526 21 Hanoi Statistical Office (2011) Hanoi statistical yearbook 2010 Hanoi Statistical Office, Hanoi 22 Kawai K, Osako M (2011) Estimation of recyclable waste flows in Hanoi, Vietnam (in Japanese) Environ Sanit Eng Res 25:21–29 23 Ministry of Health and Welfare of Japan (1977) Protocol of waste analysis, Notification of Kansei 95th (in Japanese) Ministry of Health and Welfare of Japan, Tokyo 24 World Bank (1999) Municipal solid waste incineration, World Bank technical guidance report World Bank, Washington, DC 25 Tanaka N, Matsuto T, Kakuta Y, Tojo Y (2003) Fundamental knowledge of waste management engineering for recycling and appropriate disposal (in Japanese) Ghihodoshuppan, Tokyo 26 Jakobsen ST (1995) Aerobic decomposition of organic wastes Value of compost as a fertilizer Resour Conserv Recy 13:57–71 27 Zhuang Y, Wu SW, Wang YL, Wu WX, Chen YX (2008) Source separation of household waste: a case study in China Waste Manag 28:2022–2030 28 Japan International Cooperation Agency, Yachiyo Engineering Co., Ltd, Nippon Koei Co., Ltd (2009) Project completion report of the project for implementation support for 3R initiative in Hanoi city to contribute to the development of a sound materialcycle Society in the Socialist Republic of Vietnam Japan International Cooperation Agency, Tokyo 29 Charuvichaipong C, Sajor E (2006) Promoting waste separation for recycling and local governance in Thailand Habitat Int 30:579–594 ... current proximate composition of municipal solid waste would be suitable for incineration, composting and RDF production by using physical and proximate composition analyses of household waste in Hanoi,. .. ranges of change in proximate composition of household waste according to achievement rate of source separation for scenario I (household waste was separated into combustible and non-combustible waste) ... composition of household waste in Hanoi, Vietnam, and on the applicability of alternative waste management technologies with triangle diagrams Proper categorization of wastes for source separation