Expert-Analytical Estimation of Environmental Safety of Solid Household Waste Handling Processes

One of the key indicators of regional development is environ- mentally safe handling of waste including household waste. Solving the problems in this domain requires the creation of an efficient household waste management system. A mechanism for solving this problem was proposed in this study. In contrast to the existing ones, it comprehensively takes into account the formation of environmen- tal hazards at all stages of the waste handling life cycle and substan- tiates and identifies priorities of obligatory management measures to be taken at local, regional and national levels with their qualitative and quantitative expert estimation.<br><br>The study of waste hierarchy performed according to the Di- rective 2008/98/EC by the hierarchy analysis method has made it possible to determine not only the priorities of the measures en- suring environmental safety of SHW handling process but also the significance of measures at each stage. According to the calculations, contributions to the overall risk amounted to 46.15 % for disposal, 24.02 % for recycling, 10.95 % for neutralization, 10.95 % for genera- tion, 5.14 % for collection and 2.79 % for transportation.<br><br>Assessment of the factor characteristics has made it possible to find out that the handling conditions whose contribution is 54.95 % of all factors require the greatest attention during danger generation.<br><br>Effectiveness of implementation of the measures ensuring nor- mative environmental safety can be ranked as follows: 60.22 % for the local level, 22.55 % for the regional level and 17.23 % for the national level.<br><br>The study has found that the formation of awareness, conscien- tiousness, and rational consumption is the most effective measure of ensuring environmental safety making up 27.55 % among the thirteen measures assessed.<br><br>Application of the proposed method will ensure making groun- ded managerial decisions not only for the whole system of household waste handling but also for each of its stages: from waste generation to its operation.<br><br>This method is quite simple to use and can be applied at the national, regional or local levels.


Introduction
2.1 billion tons of solid household waste (SHW) are generated annually in the world and 30-40 % of this amount is not treated in an environmentally safe way. The World Bank report was released in 2018 on this issue and a forecast of this industry development up to 2050 was made. According to the report calculations, the amount of waste generated will double and reach a staggering level of 3.76 billion tons per year as a result of rapid urbanization, population growth and economic development [1].
Solid waste handling is a worldwide problem affecting literally each person. More than 90 % of waste is landfilled or incinerated in low-income countries [2]. This is one of the factors of long-term pollution of atmospheric air, soil, and groundwater.
In view of [2], study of SHW handling processes should be comprehensive and multicriterial in assessing environmental hazards and impact on the environment. It also requires qualitative and quantitative prioritization of environmental safety measures when making effective managerial decisions.

Literature review and problem statement
Ideas of «zero waste» [3] have become widespread in the 2000s, however, they are considered just as an ideology so far. To achieve the goals, comprehensive and reliable tools are required that will facilitate decision-making in the best way and support sustainable development. Decisions should have a systemic perspective, consider all actions, and make a clear estimation of alternatives.
Effectiveness of the waste management and handling system for the waste of different nature and origin depends primarily on the objects and entities generating waste. According to the factor analysis, the basic danger is associated with an inevitable waste accumulation and the derivative objects of waste handling (disposal, storage, neutralization, burial, etc.).
It is shown in [4] that about 90 % of SHW is disposed of in open dumps and waste grounds. The authors attempted to provide a comprehensive overview of management, the impact of waste recycling, its properties and handling on the environment. However, the study was concluded with only some suggestions that may be useful to encourage competent authorities and project developers to further improve the existing system. There is no comprehensive structured approach to decision making.
Assessment of the adverse effect of landfills on the environment was made in [5]. The authors have given a detailed description of groundwater and corresponding initial values established before burial. The comprehensive multi-parameter approach is useful for improving the strategy and scheme of groundwater protection and management in landfills and industrial waste-related areas.
The main objective of [6] is the study of SHW management and its place among other sectors of urban environment. A waste management index has been elaborated that can be used to compare urban areas and select management methods. In addition, a conclusion was drawn that the process of handling municipal solid waste and related infrastructure remains a serious problem for many local administrations.
An overview of national systems of municipal waste management in the context of circular economy in some European countries is presented in [7]. The article has a dual purpose. The first of them is the identification of various municipal waste management practices used in individual countries and their approaches to coverage of the circular economy. The second purpose is to determine the extent to which technologies play some role in this context.
Lack of information on SHW flows at the stages of collection and processing does not allow the policymakers and planning professionals to find appropriate environmentally and economically sound solutions. As a partial approach to solving the problem, the authors of [8] describe structure and functions of the SHW management platform based on the product-service system, in particular, data acquisition and processing, documenting SHW flows and identifying impacts on environment and human health and ways to exclude or at least reduce waste generation rate.
The study [9] compared corrections for reclamation of soils and their quality resulting from composting, turfing and pyrolysis. The financial value was established and tradeoffs between product cost and conversion efficiency were quantified.
In order to create an effective waste handling system, best international practices were considered and adapted by those European countries that have already harmonized their regulatory base with the EU laws ( Fig. 1) and brought it into line with the directives considered in [10,11].
The waste hierarchy remains a key component of the EU strategy concerning waste management. Transition to higher levels of waste hierarchy is an integral part of achieving sustainable waste management and moving to a circular economy.
Study [13] proposes a series of measures for working out routes and recovery methods that facilitate reuse of relevant products. A purposeful policy of adapting the waste recycling technology that enhances recovery of critical raw materials will encourage the use of a waste hierarchy focused on efficiency of resource use.
It is especially important to note that in order to qualitatively solve the problem of making rational decisions, it is advisable to use the methods taking into account psychological characteristics of decision-makers. One of the versions of applying the systems approach of coordinated managerial decisions is proposed in [14]. The T. Saati's hierarchy analysis method (HAM) described in detail in [15] is one of the best known and accessible to a wide circle of researchers. Therefore, the development of a new approach to the system study of feasibility of applying one or other SHW handling measures listed in Directive 2008/98/EC is an important scientific and practical objective. This will provide a comprehensive combination of objective, criteria, many factors and characteristics of conditions of their interaction.
Necessity of taking into account territorial and socio-economic features of settlements, their development, level of socio-cultural consciousness of population, concerned consumers of waste as raw materials and possibilities of waste processing is equally important.
An additional task consists in determining composition and properties of the waste itself, areas of its origin, line of production activity, climatic conditions regarding the possibility of composting, etc.
The use of a comprehensive expert-analytical approach by applying the hierarchy analysis method generally meets the requirements to complexity and multicriterial approach. The method discussed in [16] is promising for solving a series of scientific and practical problems of ensuring environmental safety and effective managerial decision making.
A substantial advantage of HAM consists in the fact that this method includes checking consistency of experts' estimates in the course of study. Consistency of entire hierar chy can be estimated by multiplying each consistency index by priority of the corresponding criterion, summing Electronic copy available at: https://ssrn.com/abstract=3705296 the obtained numbers and comparing the result with the average index of consistency of random matrices of the same order. Ratio of consistency indexes up to 10 % is considered acceptable. The current state of the SHW handling field remains a priority line of scientific and applied studies.

The aim and objectives of the study
The study objective is to improve the methodological apparatus of assessment and management of ecological safety concerning the solid waste handling processes through the use of expert-analytical procedures and comprehensive use of T. Saati's hierarchy analysis method. In contrast to the existing methods, it comprehensively takes into account both generation of environmental hazards at all stages of the life cycle of waste handling as well as substantiated and determined priorities of necessary management measures to be taken at local, regional and national levels after their qualitative and quantitative expert assessment.
To achieve the study objective, the following tasks were set: -to develop hierarchical structures of the solid waste handling processes; -to decompose the process of environmental safety management at each of the key stages using a comprehensive multi-criterion systems approach; -to study the process of solid waste handling through the use of procedures of expert analytical estimation.

Development of hierarchical structures of solid waste handling processes for the purpose of further analytical estimation
The proposed system analysis reveals the scientific and methodological approach to multicriterial expert-analytical estimation of environmental safety of the solid waste handling processes.
Ideology In this study, we used an expert-analytical estimation procedure using the adapted HAM for multicriterial integrated assessment (MIA) based on standard procedures of environmental impact assessment (EIA) [17]. The procedure was implemented and tested during studies of environmental safety of lengthy hydrotechnical facilities (LHF) and described in a algorithmic form shown in Fig. 2.
The study procedure used is outlined in [17,18]. These studies detail the conducted expert-analytical procedures and application of a modified pairwise comparison scale. This allowed the authors to shorten statements of the procedure of assessment and management of environmental safety according to the waste handling hierarchy.
The conducted study has proved the possibility of simplified use of an expert team for solving the tasks that were stated.
Is it possible to make a decision on efficient provision of environmental safety?
Experimental data Expert-analytical procedures of multicriteria complex assessment using the adapted AHP RESULTS OBTAINED: 1) hierarchical images of the problem situation; 2) weight coefficients and priorities of interaction of the problem situation elements (task)  Only two criteria were taken as the basis for experts' choice: occupation field and experience. A level of 5 years was established according to the minimum admissible experience using the general rule. All experts had more than a 10-year professional experience in the proposed study area.
To ensure maximum support for the experts to attain the study objective, they were chosen according to the areas corresponding to the hierarchy levels, namely: estimation of environmental impact, environmental safety, national administration and control and service organization activities. This choice of experts has made it possible to cover each of the study areas and structural elements of hierarchies as much as possible.
For each of the hierarchy levels, the experts were asked only one question: which of the two elements being compared is the most dangerous or significant for the top level element?
The study used both individual and group expert estimations. The results of pairwise comparisons were analyzed using the HAM procedure. One of the criteria for admissibility of experts' opinions is consistency which was less than 10 % for each of the studied hierarchies.
Decomposition of the generalized system of SHW handling processes by the levels consistent with the principles of HAM structuring for construction of hierarchical structures in a general formalized form is presented in Fig. 3 where: -the task objective that is assessment of danger to the environment caused by processes of SHW handling is formed at the first hierarchy level Ob (Objective); -sub-criteria, that is, the processes of SHW handling that create danger (generation, collection, transportation, handling) are represented at the second level SCr (Subcriteria); -criteria, that is, components of environment that are adversely affected or contaminated and assessed from the standpoint of possible hazards are represented at the third level C (Criteria); -characteristics of factors that create or contribute to the negative impact (quantitative and qualitative components of pollution, etc.) are considered at the fourth level ChF (Characterization of Factors); -grouped objects that have a negative impact on environment are considered at the fifth level Go (Object Groups); -sources of danger whose impact on the possibility of environmental safety management of the SHW handling hierar chy to be assessed in the synthesis process are considered at the sixth level SD (Sources of Danger); -territorial level of implementation of the measures according to the authority principle (local, regional, national) is formed at the seventh level TLI (Territorial Level of Implementation); -environmental measures that provide mitigation of negative impact and aimed at achievement of a normative level of environmental safety are considered at the eighth level SM (Security Measures).
All the SHW handling processes listed in Fig. 3 are sub-criterial which are discussed below as separate hierarchical structures obtained by decomposition on a similar principle with exception of the intermediate levels.

Decomposition of environmental safety management tasks and expert-analytical studies of all processes of solid waste handling using a multi-criterion comprehensive systems approach
The proposed hierarchical structure of environmental hazard formation in the process of SHW generation and application of measures to reduce negative impact on environment is presented in Fig. 4. The overall consistency of Ob The process of SHW handling as a danger for environment experts' opinions for the whole scheme is 0.03371 which satisfies the HAM requirements [15]. The values of generalized weight coefficients and priorities in percentages obtained by the use of expert-analytical procedures with application of the program that implements the HAM are given in brackets.
Relationships between the hierarchy elements were established on the basis of characteristics of interaction of the elements of adjacent hierarchy levels.
An example of the developed approach to formulation of characteristics of contents of connections between elements of the adjacent upper and lower levels of the hierarchical structure and formulation of questions to the experts in the assessment process are given in Table 1.
The results of assessment of environmental hazard of the SHW generation process and the priority of measures to reduce negative impact on environment depend significantly on the formulations set forth.
Similarly to the SHW generation operation, decomposition of the task of environmental hazard assessment has been carried out and priority of management and control measures in the SHW collection process was established (Fig. 5).  Electronic copy available at: https://ssrn.com/abstract=3705296 Table 1 An example of the developed approach to formulation of characteristics of content of relationship between elements for the process of SHW generation The hierarchy level name The lower-level elements associated with the corresponding higher-level hierarchy element The relationship characteristic that reveals essence of interaction or influence between elements of the assessed level from the position of existing higher level and aspects of the overall purpose of assessment 1 2 3 Relationships between an element of Level 1 (Objective) and the elements of Level 2 (Criteria).
Setting the task for experts for pairwise comparison of Level 2 elements: Which of the environment components can be subjected to a more direct impact in the process of SHW generation?   Impact of the measure on the source of hazard. For example, the use of environmentally safe packaging materials that can decompose into environmentally safe components on their own, including promotion of clean purchases SM3: Primary waste sorting Impact of the measure on the source of hazard. Waste sorting (usually packaging and packaging materials) as they are formed. This type of sorting makes it possible to qualitatively separate waste as a salvage which facilitates or increases the number of options for further treatment, reduces their quantity and improves qualitative composition SM4: Accounting for waste consumption and waste generation forecasting Impact of the measure on the source of the hazard. Accounting consumption and forecasting the SHW generation (waste handling plans) take into account: -geographical features of the waste generation area, type, quantity and source of waste produced in the area, organizational aspects related to waste handling including description of distribution of responsibilities between public and private waste handling entities; -assessment of usefulness and applicability of economic and other tools in solving various waste problems taking into account the need to support proper functioning of the domestic market; -use of awareness-raising campaigns and provision of information aimed at general public or a specific set of consumers; -historic sites of contaminated waste disposal and measures of their rehabilitation SM5: Waste storage (accumulation) conditions before collection, transportation, or subsequent handling Impact of the measure on the source of hazard. This choice of optimal conditions of waste accumulation for subsequent operations that minimize impact on environment components (choice of storage location, amount of accumulation before transfer, etc.) Table 1 Electronic copy available at: https://ssrn.com/abstract=3705296

Continuation of
Overall consistency of experts' opinions for the whole scheme was 0.0385 which satisfies the HAM requirements [15]. The values of generalized weight coefficients and priorities in percentages obtained by application of the expert-analytical procedures using the program that implements the HAM are given in brackets.
The task of decomposition of the SHW transportation process and assessment of environmental hazards and priority of management and control measures is shown in Fig. 6. The overall consistency of the experts' opinions for the whole diagram was 0.049 which satisfies the HAM requirements [15]. The values in brackets show generalized weights and priorities in percentages obtained by application of expert-analytical procedures using the program of HAM implementation. Fig. 7. The overall consistency of the experts' opinions for the whole diagram was 0.046 which meets the HAM requirements [15]. The values in brackets show generalized weight coefficients and priorities in percentages obtained by application of expert-analytical procedures using the program of HAM implementation.

Assessment of the SHW operation process is shown in
As a result of the expert-analytical study of SHW operation, it was established that the danger of this process can be ranked according to the components as follows: 75.14 % for disposal, 17.82 % for recycling, 7.04 % for neutralization (processing, reprocessing). These values fully confirm the European ideology of waste handling set forth in Directive 2008/98/EC.

Synthesis of an SHW handling system with subsequent hierarchy analysis
Summarizing the results of decomposition of the tasks of each of the SHW handling operations with grouping the objects that have a negative impact, it is advisable to add a territorial level of measure implementation in the synthesis process. This is an important criterion for assessment during implementation of the policy of decentralization of public administration in Ukraine and focusing on objectives of sustainable development (Fig. 8). The overall consistency of the experts' opinions for the whole scheme was 0.056 which satisfies the HAM requirements [15]. The values in brackets show generalized weight coefficients and priorities in percentages obtained by application of the expert-analytical procedures using the program that implements the HAM. Fig. 8 Fig. 8 is as follows:

Contents of the elements of level 8 marked in
-SM1: accounting, control and forecasting of SHW handling management; -SM2: use of environmentally safe packaging materials; -SM3: generation of awareness, consciousness and rational consumption; -SM4: primary sorting of SHW; -SM5: use of the best available technologies in the process of SHW handling management; -SM6: interested consumers of SHW; -SM7: development of schemes of sanitary cleaning of settlements; -SM8: separate collection of secondary raw materials; -SM9: compliance with the rules of transportation safety; -SM10: creation of conditions of safe waste storage (accumulation) and collection; -SM11: quality of roads; -SM12: protection of SHW collection sites; -SM13: economic promotion of environmentally safe waste handling.

1. Study of the process of SHW generation
Expert-analytical studies of the process of solid waste generation (Fig. 4) have made it possible to find out that biota (C4) can be subjected to the most dangerous impact which makes up 50.34 % of total contribution and is characterized exclusively by anthropogenic influence. Hazard for other complex environmental components is ranked as follows: 21.96 % for soil (C3); 18.41 % for air (C1); 9.29 % for water (C2).
Analysis of characteristics of the factors that create a negative impact has shown that the greatest contribution (63.76 %) to the danger of the SHW generation process for environment is caused by absence or poor quality of management and control of SHW handling management (ChF4). Growth of waste danger (22.28 %) in the process of accumulation caused by influence of external factors and climatic conditions is the second most important factor (ChF3). Quantitative (ChF1) and qualitative (ChF2) characteristics of SHW composition have the lowest contribution to hazard generation and do not exceed 10 % each.

2. Study of the SHW collection process
As a result of the expert-analytical study of the SHW collection process (Fig. 5), it was found that biota (C4) and soil (C3) can have the most dangerous impact (up to 38.25 % of the total contribution of all components). The result is characterized by both peculiarities of location of collection sites and the impact of the waste itself.
Distribution of hazards for other environmental components is as follows: 17.54 % for air (C1); 5.96 % for water (C2).
Analysis of the characteristics of the factors that create a negative impact has revealed that the greatest contribution to the risk of the SHW collection process for environment includes absence or poor quality of ChF4 management and control of SHW management measuring 66.31 %. The second by importance factor is the increase in danger of waste in the process of accumulation caused by biochemical processes of decay and decomposition, influence of external factors and climatic conditions measuring 20.38 %. The quantitative (ChF1) and qualitative (ChF2) characteristics of the SHW composition make the lowest contribution to hazard generation and do not exceed 10 % each.
Generalized contributions of types of the sources of generation (SD) to hazards for environment can be ranked as follows: -

3. Study of SHW transportation process
As a result of the expert-analytical study of the SHW transportation process (Fig. 6), it was found out that air (C1) can be subjected to the most dangerous impact: 54.62 % of the total contribution. According to the experts, this is caused by intensive processes of waste biodegradation and additionally by transport activities which are the main air pollutants. Hazard for other environmental components is as follows: 23.23 % for soil (C3); 13.77 % for biota (C4); 8.38 % for water (C2) Analysis of characteristics of the factors that create a negative impact has revealed that the greatest contribution (48.25 %) to the danger of the SHW transportation process is caused by violation of safe conditions of waste transportation (because of the threat of unauthorized waste disposal). The next most significant factors include unsatisfactory level of management and control of SHW handling and the qualitative characteristics of SHW composition: about 20 % each. Quantitative characteristics of SHW composition have the lowest contribution to hazard generation: 11.06 %.
Generalized contributions to the hazard generation for environment made by the types of SHW sources are as follows: -

4. Study of the SHW operation process
Expert-analytical studies of the SHW operation process (Fig. 7) have allowed us to establish the following.
Hazards for environmental components can be ranked as follows: 59.83 % for air (C1); 16.79 % for soil (C3); 14.39 % for biota (C4); 8.99 % for water (C2). This is caused by high anthropogenic loads from the operating processes on atmospheric air including aerobic and anaerobic processes of decomposition of the waste mass as well as waste burial prevailing over safer disposal methods.
Analysis of the characteristics of factors (ChF) that create negative impact has shown that the conditions of operation with increasing danger (ChF3) make the greatest contribution to the dangerous impact of the SHW operation process on environment (54.95 %), for example, the obvious prevalence of pollution caused by waste incineration without obtaining energy compared to composting.
The next most significant factors include unsatisfactory level of management and control (ChF4) of the operation process (24.76 %). Quantitative (ChF1) and qualitative (ChF2) characteristics of SHW operation have the lowest contribution to hazard generation: 12.32 % and 7.97 %, respectively.

5. Final study of the process of SHW handling
Due to the expert-analytical study, it was possible to determine for the first-time contributions of each of the components of the SHW handling process (Fig. 8)  Analysis of characteristics of the factors that create a negative impact has shown that the greatest contribution to the danger for environment is made by ChF3, that is, the conditions of SHW handling (54.95 %). The next most significant factors include unsatisfactory level of management and control (ChF4) of the handling process (24.76 %), quantitative and qualitative (ChF1 and ChF2, respectively) characteristics of SHW handling have the lowest contribution to hazard generation measuring 11.93 % and 8.36 %, respectively.
According to the calculations, the contribution of Go1, that is, the sources of waste generation to the overall hazard (87 %) is almost 7 times higher than the contribution of Go2, that is, the sources of operation (13 %). The above result is important in development of measures to improve environmental safety since most studies and government programs are aimed specifically at combating pollution consequences rather than the causes of their occurrence.
Generalized contributions of the SHW source types to cause hazard for environment are as follows: - Establishment of territorial features of implementation of measures to improve environmental safety of SHW handling is an important result of the study. It is essential in conditions of implementation of public authorities at regional and local levels. According to the calculations, contributions of implementation of measures were distributed as follows: 60.22 % for local level; 22.55 % for regional level; 17.23 % for national level.
Contributions of SHW handling processes to the overall danger for environmental components are presented in Table 2. The results obtained make it possible to compare dangers for environments components at each stage of the SHW handling life cycle. The bottom row of the table by its values is not the arithmetic mean of all processes which indicates the presence of system-wide emergent properties. It should be noted that competence of the specialists involved, their experience in using expert-analytical methods is the main limitation of adequacy and reliability of studies by similar methods. Ability of experts to harmonize individual and team work is of significance for making coordinated decisions.
In view of the above, application of a comprehensive expert and analytical approach using the hierarchy analysis method to assess the processes and objects of SHW handling is a promising way of supporting effective managerial decisions. Its further development and implementation in securing environmental safety are expedient for use as a methodological tool for implementing the public authority principles.

Conclusions
1. The hierarchies developed in this study reveal the content of SHW handling processes at all stages of their life cycle: generation, collection, transportation and operation (neutralization, recycling, disposal). Ideology of T. Saati's hierarchy analysis method (HAM) makes it possible to comprehensively analyze and take into account mutual influence of all elements. The hierarchical structures that were elaborated describe in a clear and spatial way how the SHW handling processes endanger environmental components, their nature and principles of generation. Current management and control measures were considered as well.
2. The expert-analytical assessment that was carried out through a consistent review of all waste handling processes has provided an opportunity to synthesize the results obtained. The generalized hierarchical structure has allowed us to take into account additional emergent system properties for application of effective measures for managing environmental safety of waste handling.
3. The obtained values of generalized weight coefficients of hierarchy reveal in a new way the essence of generation of environmental hazards caused by waste handling. Priorities of integrated management and control measures aimed at reduction of hazards were defined more exactly as well. As a result of the expert-analytical study, it was possible to establish contributions to the overall environmental hazard made by each of the SHW handling components: disposal (46.15 %), recycling (24.02 %), neutralization (10.95 %), generation (10.95 %), collection (5.14 %), transportation (2.79 %). Hazards of the waste handling processes for environmental components are ranked as follows: 46.93 % for air, 19.01 % for water, 17.86 % for biota, 16.20 % for soil. Assessment of the factor characteristics has made it possible to find out that conditions of waste handling require the greatest attention during hazard generation. Its share is 54.95 % of all factors. According to the calculations, contribution of waste generation sources to the general hazard is almost 7 times higher than the contribution of consumption sources. Formation of environmental hazards was taken into account for all stages of the waste handling life cycle. Priorities of the measures aimed at environmental safety management to be taken at local, regional and national levels were substantiated and their values determined. Effectiveness of implementation of the measures ensuring normal ecological safety can be ranked as follows: 60.22 % for the local level, 22.55 % for the regional level and 17.23 % for the national level. It has been found that formation of people's awareness, conscientiousness and rational consumption are the most effective measures accounting for 27.55 % among the thirteen environmental safety measures assessed according to the principles of Directive 2008/98/EC.