Scenarios of the development of municipal solid waste management system
To assess the current situation and the potential for reducing GHG emissions from the MSW management industry, three scenarios of the development of the Russian waste management system had been elaborated. The developed scenarios are based on the official statistics data on the amount of waste generated and treated, and also on the adopted legislative acts that determine the development directions of the Russian waste management system and set targets in these areas (Council for Strategic Development and National Projects 2018). That is why the developed scenarios include such measures to improve the waste management system as elimination of unauthorized dump sites, introduction of landfill gas collection and utilization systems at the landfills, incineration of waste with energy recovery, separate collection of waste, and recycling of utilizable waste fractions, and do not include other waste-to-energy technologies and waste treatment strategies contributing to climate change mitigation. Separate collection and treatment of biowaste is not applied in the national waste management strategy of the Russian Federation (Government of the Russian Federation 2018) and therefore was beyond the scope of the elaborated scenarios. For the purpose of the current study, three scenarios had been developed.
Scenario 1: BASIC (business as usual)
This scenario is based on the current waste management practices, under which 90% of the generated mixed MSW is disposed of on landfills and dump sites. According to the 6th National Communication Report of the Russian Federation to UNFCCC, the total MSW generated that found its way to managed landfillsFootnote 1 was 49.209 Mt in 2009, while the amount of MSW disposed in unmanaged disposal sites (dumps) was 5.067 Mt. In 2017, the amount of MSW generated was 58.4 Mt with 10% being diverted from landfills: 3% incinerated and 7% recycled (Ministry of Natural Resources and Ecology of the Russian Federation 2019). According to Russian Federation 2019, landfill gas recovery is not taking place at Russian landfills. This scenario implies the closure of unorganized dump sites, with all the waste to be disposed of on managed dump sites or landfills only.
Scenario 2: REACTIVE (moderate development)
The reactive scenario implies a moderate development of the waste management sector, based on the construction of several large incinerators, a small increase in the share of waste to be recycled and the disposal of remaining waste at sanitary landfills,Footnote 2 with the closure of all the existing unorganized dump sites. In this scenario, all Russian regions were divided into two clusters: the first cluster included the city of Moscow and the Republic of Tatarstan, where new waste incinerators are being built, and the second cluster which includes — all the other cities and regions.
Moscow and the Republic of Tatarstan
In Moscow and Tatarstan together, 8.586 Mt of mixed MSW is generated annually (Cabinet of Ministers of the Republic of Tatarstan 2018; Department of Housing and Communal Services of the city of Moscow 2019). In an attempt to introduce the waste-to-energy technology in Russia, an international consortium that consists of Swiss, Japanese and Russian firms is currently involved in constructing five state-of-the-art incineration plants in these two areas. Four incinerators are to be built in the Moscow region and one in Kazan, the capital of the Republic of Tatarstan. The annual combined capacity of the four plants in Moscow will be about 2.8 Mt of MSW, and the one of Kazan 0.55 Mt (Bioenergy International 2019; Regnum 2017). In this scenario, it is assumed that compared to the basic scenario, the share of waste undergone recycling is increased to 10%, i.e., 0.859 Mt annually. Furthermore, these 10% would be transferred to recycling plants to recover secondary raw materials. The remaining 4.377 Mt of mixed MSW would be disposed of in sanitary landfills.
Other cities and regions
In the other cities and regions of Russia, in accordance with the Development Strategy of Waste Recycling Industry until 2030 (Government of the Russian Federation 2018), over two hundred new eco-techno parks (i.e., waste recycling complexes) will be built. These facilities will receive mixed MSW that will be sorted there for recycling purposes. Under this scenario, it is also assumed that compared to the basic scenario, the share of waste undergone recycling is increased to 10%, thus transferring 4.982 Mt annually of the mixed MSW to recycling plants. The remaining 44.932 Mt of MSW are disposed of in sanitary landfills.
Scenario 3: INNOVATIVE (active development)
This scenario is based on the legally established priority areas for the development of the industry (Council for Strategic Development and National Projects 2018; Government of the Russian Federation 2018). The scenario implies deep changes in the industry with the introduction of technologies for incineration, separate collection and recycling of waste. In this scenario, the regions of Russia are divided into three clusters, in accordance with the possibilities of improving the infrastructure for waste management and the need for secondary resources and energy received during the processing of waste. When determining the share of waste to which this or that treatment method is applied, federal targets (Council for Strategic Development and National Projects 2018; Government of the Russian Federation 2018) and estimates made by the World Bank (Korobova et al. 2014) were used.
Moscow and the Republic of Tatarstan
The first cluster includes two huge, densely populated urban agglomerations in which large incineration plants are under construction: Moscow and Tatarstan. With the construction of new waste incinerators, 3.35 Mt of mixed MSW will be incinerated annually. It is assumed that some 10% of mixed MSW (0.859 Mt) generated in these two regions is to be transferred to eco-techno parks for secondary raw material recovery. Some 20% of the MSW (1.712 Mt) is to be recovered from separately collected waste, and the rest of 2.66 Mt (31%) to be disposed of in sanitary landfills.
Cities with more than 0.5 million inhabitants
This cluster includes large urban agglomerations with developed industry and high demand for materials and energy resources. In this cluster, approx. 28 Mt of MSW is generated annually (Korobova et al. 2014). Under this scenario, it is assumed that waste incineration plants are also built in some larger cities, besides Moscow and Kazan. However, the exact quantity and capacity of these plants is yet unknown; it was assumed that in comparison with the basic scenario, in this scenario, the share of incinerated waste increased to 10%, the share of recycled waste to 15%, and a separate waste collection system is partially implemented. Hereby, 10% of the generated mixed MSW (2.79 Mt) is undergoing incineration, 15% (4.185 Mt) is transferred to sorting facilities for secondary raw material recovery, some 20% of the MSW (5.58 Mt) is recovered from separately collected waste and the rest 55% (15.345 Mt) is disposed of in sanitary landfills.
Smaller cities with less than 0.5 million inhabitants and rural areas
This cluster includes smaller cities and towns with some industrial enterprises, as well as rural areas. The amount of waste generated annually in this group of settlements is 21.914 Mt. It is assumed that no waste is incinerated, 15% of the mixed MSW (3.287 Mt) is transferred to sorting facilities for secondary raw material recovery, 10% (2.191 Mt) is recovered from separately collected waste, and the rest 75% (16.435 Mt) is disposed of in sanitary landfills.
Waste flow diagrams corresponding to the three scenarios with their input and output flows are shown in Fig. 1.
In all the three scenarios, mixed MSW is transferred to sorting facilities where the recovery of valuable materials by mostly hand sorting takes place. Detailed accounts of process efficiency for material recovery facilities, in terms of recovery rates and quality of recovered materials, are scarce in the published literature (Cimpan et al. 2015). In the study of Cimpan et al., 2015, at least three data sets were evaluated with the result that 13–45% of paper, 3–49% of glass, 35–84% of metals and 1–73% of plastics were recovered from the plant input of these materials. Two other studies report similar recovery rates between 60 and 95% for paper, glass, plastic and aluminum for hand and automatic sorting test trials (CalRecovery, Inc and PEER Consultants 1993; Hryb 2015). Based on this data and the results of the authors’ own experimental studies on manual waste sorting in Russia, the recovery rates for the most valuable waste fractions, including paper/cardboard, glass, metals and plastics had been calculated (Table 1). In the Scenario 3, separate collection of paper/cardboard, glass and plastic is introduced. Recovery rates related to the input of the corresponding waste type into each waste management cluster (see Table 1) for Moscow and Tatarstan as well as for the cities with more than 0.5 million inhabitants are considered to be higher than for the settlements with less than 0.5 million inhabitants.
For the comparison of GHG emissions of the three elaborated scenarios, a specific assessment model was elaborated.
The calculation of the amounts of released and avoided GHG emissions for the different considered waste treatment technologies are based on the 2006 IPCC Guidelines for National Greenhouse Gas Inventories. The IPCC methodology is scientifically widely recognized and used internationally, which makes the results easy comprehensible and easier to compare with other studies.
For the elaboration of the model that would allow calculating the GHG balance emissions, the upstream-operating-downstream (UOD) framework (Gentil et al. 2009) was used, where direct emissions from waste management procedures and indirect emissions from upstream and downstream activities are differentiated. On the upstream side, the indirect GHG emissions, like those related to fuel and material extraction, processing and transport as well as plant construction and commissioning, are excluded from the consideration. Indirect emissions from infrastructure construction on the downstream side are outside the system boundaries and not accounted for as they are relatively low (Boldrin et al. 2009; Mohareb et al. 2011). Direct GHG emissions from the waste transport are also excluded from the system boundaries since they are negligible comparing to the direct emissions from the waste processing/treatment (Weitz et al. 2002; Wuensch and Simon 2017). Since indirect GHG emissions avoided due to energy and material substitution, as well as carbon sequestration in the downstream processes is significant, they are included into the model. The conceptual framework of the model and its boundaries are shown in Fig. 2.
The inputs to the model are waste (its quantity, composition, carbon content fixed in biomass and no-biomass), as well as energy and fuel that are used in the waste treatment processes (see Table 2 and Figs. 1, 2 and 3). The outputs include generated and delivered electricity, recovered secondary materials and sequestrated carbon.
The analysis of MSW composition is not regularly done in Russia, and only a limited number of studies on this subject are published. Since waste composition is the basis for the determination of direct GHG emissions from waste management activities, accurate data is desirable. The Russian Federation is a huge country with both densely populated urban areas and sparsely populated rural areas. Due to the different settlement structures, the waste compositions also differ a lot. It is not expedient to assume an average composition for the entire country. Therefore, hereinafter three clusters had been considered to define waste compositions. The first cluster includes Moscow and the Republic of Tatarstan, since in these regions, a larger amount of mixed MSW is/will be incinerated in the nearest future. The second cluster includes the cities with the population of more than 0.5 million people, and the third cluster includes the settlements with the population of less than 0.5 million people. The waste compositions for these three clusters given in Table 2 are weighted averages of the results of a number of experimental studies of waste composition which were found in sources of the literature published after 2010 and further analyzed. Weighted average here means that the respective data on waste composition that was found for a city or region was included in the weighted average with the proportion that the amount of MSW generated in the city or region takes up as part of the total mass of MSW generated in the respective cluster.
To determine the avoidance of GHG emissions in the downstream processes by means of energy and material substitution as well as carbon sequestration, a compensatory system must be used. In Fig. 3, the compensatory system for the substitution of energy and primary materials is shown.
It is necessary to know the emission factors when calculating GHG emissions from thermal treatment of waste, and also when compiling national emissions inventories (Larsen and Astrup 2011). Information on GHG emission factors of various solid waste treatment technologies for each country is of great importance for the assessment of GHGs emitted as a result of adopting a certain technology. However, such factors are not available for the Russian Federation, which implies using the data available in the literature for the countries with the conditions similar to the Russian ones, examining local circumstances of solid waste management system (Friedrich and Trois 2013; Larsen and Astrup 2011; Noya et al. 2018).
There are different factors affecting GHG emission levels from waste incineration. One of the most important factors in determining CO2 emissions is the amount of fossil carbon in the waste stream meant for incineration. Non-CO2 emissions are more dependent on the incineration technology and conditions, and for modern waste incinerators, the amounts of non-CO2 emissions are negligible (Johnke 2001; Sabin Guendehou et al. 2006).
The amount of fossil carbon was calculated based on waste composition, carbon content and share of fossil carbon given in Table 2; the resulting fossil carbon content in wet waste was 0.117 kg C/kg. For the indirectly avoided GHG emissions, the recovery of electricity with a net efficiency of 24% for all the scenarios and for the Scenario 3 also from metals contained in the incinerator slag to substitute primary metals was considered. The recovery of heat in form of process steam or district heat was not considered in the scenarios (Dashieva 2017). Further parameters for the calculation of GHG emissions from waste incineration are given in Table 3.
For the calculation of the impact of the methane released from landfills to climate change over a 100 years’ time horizon, the first-order decay kinetics model was used. Almost 80% of the Russian MSW landfills occupy an area larger than 10 ha (Volynkina and Zaytseva 2010). Here, it is assumed that all the MSW is highly compacted and disposed of in deep landfills under anaerobic conditions without the recovery of landfill gas (Govor 2017). Since no landfill gas is recovered, in Scenario 1, only the sequestrated non-biodegradable biogenic carbon in the landfill results in avoided GHG emissions. There is an intention in Russia to introduce the collection of landfill gas as the primary measure to reduce GHG emissions from the waste management sector (Government of the Russian Federation 2018; Ministry of Natural Resources and Ecology of the Russian Federation 2013) within the next years. In the literature, methane recovery rates between 9% (Scharff et al. 2003) and 90% (Spokas et al. 2006) are reported. For example, most US landfills are well-controlled and managed; in particular, in California, gas collection efficiencies are as high as 82.5% (Kong et al. 2012). Based on these values, for both Scenario 2 and Scenario 3, landfill gas recovery is introduced with a recovery rate of 60%. Under these two scenarios, in addition to carbon sequestration, the recovered landfill gas is used to produce electricity, which results in avoided indirect GHG emissions. Other parameters used for the calculation are mainly taken from the latest Russian National Inventory Report where IPCC default parameters were used (Pipatti et al. 2006; Russian Federation 2019). The parameters used for the calculation of GHG emissions from landfills for all the three scenarios are shown in Table 4.
In all the scenarios, some part of mixed MSW is treated in eco-techno parks, where valuable secondary raw materials like metals, paper, glass and plastics are recovered, and the sorting residues are forwarded to landfills. In addition, separate collection of some amounts of paper, glass, and plastics in the Scenario 3 is presumed. The corresponding recovery rates are already given in Table 1. Each recovered secondary material substitutes a certain amount of primary material. Since the production of primary materials is usually connected with higher energy and raw material consumption than that of the secondary materials, more GHGs are released during the production of the former ones. Therefore, every unit of recovered secondary material obtained leads to a reduction in released GHGs.
GHG emission or substitution factors are developed for specific geographical areas and technologies, and their appropriateness to other circumstances may be questionable (Turner et al. 2015). The application of one specific emission factor for a recovered material in the whole Russian Federation would already be debatable due to the size of the country. Perhaps that is why emission factors for Russia cannot be found in the literature. For this study, the average values of GHG emission/substitution factors determined for other industrial countries from the study of (Turner et al. 2015) were used. The amounts of avoided GHG, i.e., the values of the emission factors in CO2 equivalents for the recovered valuable waste fractions, including steel, aluminum, paper/cardboard, glass and plastic, are given in Table 5.
In Table 5, the used equivalent factor (Global Warming Potential over a time horizon of 100 years) of released methane versus carbon dioxide, the emission factor of the use of fuel oil in the waste incineration process and the substitution factor of delivered electrical power are shown. The emission factor of the generated electricity in the Russian Federation is relatively low, since approx. half (52%) of the electricity is produced by natural gas and approx. 13% by hydro- and nuclear power, while only 13% is produced by coal (British Petrolium 2019; U.S. Energy Information Administration 2017). The electricity mix factor is therefore only 0.358 Mg CO2-eq./MWh generated electricity (Gimadi et al. 2019).