Environmental Impacts Assessment

Environmental Impacts Assessment

17.1 ENVIRONMENTAL IMPACTS ASSESSMENT Raffaello Cossu, Alberto Pivato and Alberto Barausse INTRODUCTION Environmental impact assessment (EIA) is a pr...

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17.1 ENVIRONMENTAL IMPACTS ASSESSMENT Raffaello Cossu, Alberto Pivato and Alberto Barausse

INTRODUCTION Environmental impact assessment (EIA) is a procedure aimed at ensuring that the environmental implications of decisions are fully considered before the decisions are made. The term “environmental impact” is used to define the alteration of the environment with respect to a “reference” state caused by human activities carried out to implement a program or carry out work. The term “reference state” is used to indicate the state of the environment, whether this be a natural environment or an environment previously modified by man, before the alteration. In this context, the concept of environment includes the complex set of physical, social, cultural, and esthetic factors affecting the individuals and the communities they belong to. The procedure of EIA aims at evaluating, in the sense of identifying and quantifying, the relationship between the proposed work and the environment in which it is to be implemented. This task is carried out by taking information of various kinds (environmental, social, economic, regulatory, etc.) into account to make an informed judgment on the environmental sustainability of the task. Numerous methods have been proposed for the assessment of environmental impact, many of which emerged during the first half of the 1970s. In the present chapter a specific approach for landfills, based on the works of Cossu et al. (1986) and Andreottola et al. (1989) is presented and commented.

ENVIRONMENTAL IMPACT ASSESSMENT METHODOLOGIES The methodologies put forward to date for use in the EIA of landfilling are based on the reformulation of broad methodologies, summarized in the following sections (Moore 1973; US-EPA, 1974; US-EPA, 1998; Canter, 1999). “Overlapping map” method This method consists in the overlapping of maps describing all the considered elements of impact onto maps of various themes (socioeconomical, morphological, hydraulic, landscape, etc.) to highlight the areas of minimum and/or maximum impact. This method has been applied mainly to studies relating to the siting of infrastructures, roads, motorways, oil and gas pipelines, etc.

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Lists of questions and checklists The list of questions is a series of queries focusing on the different environmental problems that may be encountered. These lists are necessarily compiled by involving as many experts, corporations, citizens, and other stakeholders as possible, and focus on aspects which will subsequently represent the object of the study. The control list, or checklist, represents an evolution of the list of questions; it attempts to provide a systematic means of identifying the activities and elements of impact that may influence both the environment and the environmental categories present. Networks The method introduces a falling sequence of cause/effect conditions: in this way it facilitates the identification of primary, secondary, and tertiary impacts, thereby enabling the assessment of cumulated impact as long as the probability of the event happening (the occurrence of impact), its degree of importance and its size are taken into consideration. On closer examination, the latter two factors represent an analogue of the two numbers examined in Leopold’s matrix (Leopold, 1971). This method, also known as “impact tree,” was applied by Sorensen (Sorensen, 1971) to assess the impact generated by construction of a road. Correlation matrices The matrices may be considered as two-dimensional control lists illustrating on one dimension the individual characteristics of a project (proposed activities, elements of impact, etc.), while on the other listing the environmental categories that may potentially be affected by the project. The effects or potential impacts are therefore identified by intersecting the two control lists. The differences between the various proposed types of matrix can largely be observed in the variety, number, and specificity of control lists, as well as in the system of evaluation of the identified impact. With regard to evaluation, this ranges from mere identification of the potential impact to qualitative (weak, moderate, strong, etc.) or quantitative evaluation, which may be either absolute or relative: the evaluation is generally conducted in relation to the outcome of the impact (positive or negative). Numerical evaluation is frequently subject to criticism as it may suggest the introduction of a criterion of objective judgment that is actually hard to achieve, also given that environmental impacts typically affect multiple environmental categories and stakeholders, each with their own requirements for the status of the environment. In Table 17.1.1, examples of different scale of evaluations are reported. Modeling methods This class groups different methodologies, all featuring the use of mathematical models to quantify environmental impact. In the case of landfills, important methodologies employing modeling techniques include life cycle impact assessment (LCIA), risk assessment (RA) and environmental noise impact assessment procedures. In some cases, the results of these methodologies are reported in the form of correlation matrices.

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Table 17.1.1 Example of different scales commonly applied for environmental impact evaluation us-

ing the matrix approach Class of Impact

Numerical Scale

Symbol Scale

Chromatic Scale

Extremely positive value

þ2

Dark green

Positive value

þ1

Light green

Neutral value

0

White

Negative value

1

Orange

Extremely negative value

2

Red

THE LANDFILL MATRIX APPROACH The approach is based on the works of Cossu et al. (1986) and Andreottola et al. (1989) who used the matrix approach with chromatic tonalities to facilitate the understanding of the final results of the EIA performed for sanitary plants. The methodology The methodology is based on a “decisional procedure” consisting in a series of steps common to other standard environmental assessments (LCA, Multicriteria analysis, RA, etc.). All steps should be followed to successfully apply the operative module described below to sanitary landfills. Scope The scope of the study should be defined. Typical objectives include the following: • To assess different scenarios to define the feasibility of alternative solutions, such as: a single project on a single site; more than one project but related to only one site; one project at different sites; more than one project at more than one site; a project that has already been carried out. • To identify and quantify the direct and indirect significant effects of the landfill on the following factors (environmental categories): population and human health; biodiversity; land, soil, water, air and climate; material assets, cultural heritage and the landscape; interaction between the factors previously mentioned. • To investigate the feasibility, effectiveness, and implications of the proposed mitigation or compensation measures. • To identify, predict, and evaluate the residual environmental impacts (i.e., after all practicable mitigations) and cumulative effects expected to arise during the entire service life cycle of the landfill.

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• To design and specify the environmental monitoring and audit requirements. • To select the most sustainable alternative. Definition of temporal and spatial scale The temporal scale of the assessment should cover all life stages of the service life cycle of the landfill (Yang et al., 2014), particularly as important impacts may arise both in the construction and aftercare phases (See Fig. 17.1.1): 1. Construction phase a. Site operation; for example, excavation and backfilling of soil and stone. b. Construction of the main parts of landfill body including groundwater drainage, barrier layer, bottom liner, leachate, and LFG (landfill gas) collection. c. Construction of other facilities in the landfill site, such as monitoring wells, on-site roads, and official buildings. 2. Operation phase a. Operation of the landfill; for example, the transport of waste from the outside to the landfill, the placement and compaction of waste, intermediate soil covers, top cover. b. Leachate and LFG management. 3. Aftercare Phase The operations planned for this phase consist in monitoring and maintenance activities, mainly: cap maintenance and monitoring; leachate recirculation operation and maintenance (where leachate is present); leachate collection system operation and maintenance; landfill gas collection system maintenance and monitoring; landfill gas migration control and monitoring; groundwater and surface water monitoring; and security and ground stability maintenance. The choice of the duration of the “Aftercare Phase” to be considered in the analysis is important since landfills can generate emissions to air or groundwater for decades and therefore this choice, to some extent subjective, may influence the result of the assessment. Each phase may be characterized by an “ordinary” or “extraordinary” function. The latter term refers to the occurrence of exceptional events (earthquakes, hurricanes, etc.). Despite the precautionary principles and principles of the European Directive 2014/52/EU, extraordinary conditions are rarely considered in EIA and are not implemented in the current approach.

CONSTRUCTION OF THE MAIN PARTS

SITE PREPARATION CONSTRUCTION PHASE

CONSTRUCTION OF OTHER FACILITIES

OPERATION OF THE LANDFILL OPERATION PHASE

LEACHATE AND LFG MANAGEMENT

AFTERCARE

AFTERCARE PHASE System boundary

Figure 17.1.1 Service life cycle of the landfill. LFG, landfill gas.

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Spatial scale ranges from global, regional to local scales (see Table 17.1.2). The definition of spatial scale is based on spatial (area) gradations (reduction) of environmental impacts from the source (landfill) of impacts. Analysis is performed by means of technical analysis, mathematical modeling, or on the grounds of expert judgment. “Local” distances are taken as ending within 1 km of the landfill; the term “global” is considered relevant for distances more than 1000 km from the point of application. “Regional” is an area that falls between “global” and “local” scales and is therefore likely to be governed by intermediate processes between those governing the former areas. Impact evaluation Impact evaluation is the prediction, in quantitative terms as far as possible, of the significant direct and indirect effects of the landfill on environmental categories. Estimation is achieved by means of the following steps: • Identification. The procedure through which all, or at least the most relevant, impact elements of landfills are defined. Impact elements can be quantified using one or more indicators. To plan the best measures to reduce environmental impacts, causes must be linked with impacted environmental categories. The environmental categories may be defined as those components of the environment influenced by the effects generated by the elements of impact. These include not only the biophysical components of the environment (land, soil, water, air, climate, biodiversity, and ecosystem functioning) but also those more directly related to human activity (human health, material assets, cultural heritage, and landscape) (see Fig. 17.1.3). A general (although not exhaustive) list of impact elements is reported in Table 17.1.3. • Normalization. Normalization is a procedure intended to express the previously quantified impact indicators in a way to allow their mutual comparison (e.g., comparing groundwater contamination and methane emission into the air). This procedure transforms the impact values into dimensionless values (devoid of a unit of measurement) using one or more logic-mathematical functions. The most common method applied implies the normalization of the potential impact to an “acceptable-value” represented by a regulation limit or other recognized values by international organizations.

Table 17.1.2 Spatial scale for environmental assessment of landfills Scale

Local

Criteria

Impact is registered at the distance 1 km from the source (landfill)

Regional

Impact is registered at the distance from 1 to 1000 km from the source (landfill)

Global

Impact is registered at the distance exceeding 1000 km from the source (landfill)

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Table 17.1.3 Example of checklist of the impact elements for the matrix for landfill environmental impact assessments (see Also

Andreottola et al., 1989; Pivato, 2011; Pivato et al., 2013; Ranzato et al., 2012; Palmiotto et al., 2014; Yang et al., 2014) SOLID WASTE LANDFILLING j Concepts, Processes, Technologies j R. Cossu, R. Stegmann

Impact Elements

Emission of greenhouses gases

Indicators to Quantify the Impact Element

• Emission of methane, carbon dioxide, steam, etc.

Landfill • Emission of nonmethane organic pollutant gas emissions compound (NMOCs) which include volatile organic compounds (VOCs), CFC, H2S and other hazardous air pollutants (HAPs)

Causes of the Impact Element

Environmental Mitigation and Compensation Measure to Categories Affected by the Reduce the Impact Impact Element Element

Scale Analysis Temporal Scale

Spatial Scale

• Point emissions from flares and engines • Diffusive emission from landfill surface • Breakdown of biogas treatment plant • Intermediate cover/daily cover operation • Failure of the top cover system • Leaking gas wells

• air • Climate

• Operation • Air quality monitoring phase (to inform subsequent • Aftercare measures) phase • Waste pretreatment • Waste compacting degree optimization • Cover soil operation optimization (frequency, quality and quantity of materials, etc.) • Top cover typology • In situ aeration, biocover • Job opportunities

• Global

• Point emissions from flares and engines • Diffusive emission from landfill surface • Intermediate cover/daily cover operation • Failure of the top cover system

• air • Population and human health • Biodiversity

• Operation • Air quality monitoring phase (to inform subsequent • Aftercare measures) phase • Waste pretreatment • Waste compacting degree optimization • Cover soil operation optimization (frequency, quality and quantity of materials, etc.) • Top cover typology • Water spraying • Job opportunities

• Local • Regional

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• Local

• Air • Type of waste • Population • No intermediate cover/ and human daily cover operation health • No final top cover • Bad function leachate treatment plant or of gas collection system • Low compaction • Waste unloading

• Operation • Air quality monitoring phase (to inform subsequent • Aftercare measures) phase • Waste pretreatment • Waste disposal and spreading time optimization • Waste compacting degree optimization • Cover soil operation optimization (frequency, quality and quantity of materials, etc.) • Top cover typology • Improvement of the construction and operation of the gas extraction system • Job opportunities

• Local • Regional

• Installation and start of • Population construction and human • Transport of material for health construction • Biodiversity • Transport of waste • Waste compaction

• Effective exhaust mufflers for work vehicles • Waste transport, disposal and spreading time optimization • physical noise barriers as soil berms • Job opportunities

• Emission of particulate (Kg PM10/d) • Concentration of particulate (mg PM10/ m3)

• Supply of inert material • Transport of waste (traffic) • Intermediate cover/daily cover operation • Top cover system • Waste unloading

Annoying odor emissions

• Odor concentration, expressed in odor units per cubic meter (ouE/ m3), e.g., determined through dynamic olfactometry • Public interview

Noise level monitoring (dB)

Noise

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• Construction • Waste compacting phase degree optimization • Operation • Cover soil operation phase optimization (frequency, quality and quantity of materials, etc.) • Top cover typology • Alternative traffic routes • Waste disposal and spreading time optimization • Job opportunities

Emission of dust and particles

• Air • Population and human health • Biodiversity

• Construction phase • Operation phase

• Local

(Continued)

Table 17.1.3 Example of checklist of the impact elements for the matrix for landfill environmental impact assessments (see Also Andreottola et al., 1989; Pivato, 2011; Pivato et al., 2013; Ranzato et al., 2012; Palmiotto et al., 2014; Yang et al., 2014)dcont'd

SOLID WASTE LANDFILLING j Concepts, Processes, Technologies j R. Cossu, R. Stegmann

Impact Elements

Uncontrolled leachate emission into the environment

Stability of ground/ waste

Indicators to Quantify the Impact Element

Causes of the Impact Element

Environmental Mitigation and Categories Compensation Measure to Affected by the Reduce the Impact Element Impact Element

• Surface The cause of leachate • Volume of leachate (m3 waters and leakage are most related of leachate/d) groundwater to the reliability of liners, • Concentration of and consequently of their • Population leachate-originated and human failure: pollutants in nearby health groundwaters and • Biodiversity surface waters (mg of • Bad geomembrane seams and/or clay contaminanton/m3) compaction • Leachate toxicity measured using whole • Installation damage Effluent Toxicity (WET) • Failure to safeguard liner in operation • Pipes penetrating liner • Clogging of the leachate collection and removal system • Geotechnical failure • Breach by vertical pipes. • Elevated water tables in landfill, seeping out of slopes or overflow (pits) Altimetric profile measures

• Excavations • Type of waste • Waste compaction underlying soil compaction • Inadequate subsoil (compressible) • Final top cover • Landfill leachate level above bottom liner system

• Soil • Population and human health

Scale Analysis Temporal Scale

Spatial Scale

• Water quality monitoring (to inform subsequent measures) • Waste pretreatment • Waste compacting degree optimization • Cleaning drain pipes, water extraction from landfills, surface liner, groundwater encapsulation and lowering groundwater table underneath landfill, control of external water penetration into landfill body • Job opportunities

• Operation phase • Aftercare phase

• Local • Regional

• Monitoring and adjusting of landfill slope • Waste compacting degree optimization • Surface run-on and runoff controls • Landfill surveilling • Job opportunities

• Construction phase • Operation phase • Aftercare phase

• Local

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Occupation of area and volume, landscape impact

Traffic

• Surface occupation (m2) • Land vegetation coverage index • Landfill elevation (m)

Number of cars and trucks per day

Consume of material and energy for construction and operation

• Megajoules of energy or liters of diesel • Materials used for the construction of the landfill body and other facilities and for operations (tonne of sand, clay, gravel, etc.)

Adverse health and hygiene effects

• Incidence of cancer and chronic diseases, mortality studies, increase of undesirable pest species (e.g., rats)

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• Installation and start of construction • Height of landfill

• Material assets • Cultural heritage • Landscape • Land and soil

• Construction • Green compensation phase measures such as • Operation green belts, phase representing both a • Aftercare windbreak, an odor phase barrier and a buffer zone, and wide wooded zones acting as core natural areas • Improve the connectivity of important nearby ecological units and greenways • Job opportunities

• Local • Regional

• Installation and start of construction • Transport of waste

• Air • Population and human health • Biodiversity

• Alternatives routes • Waste transport, disposal and spreading time optimization • Job opportunities

• Construction phase • Operation phase

• Local • Regional

• Installation and start of construction

• Material assets

• Development and utilization of renewable (e.g., wind, solar) energy (including locally produced biogas) • Utilization of recycled materials as construction materials • Job opportunities

• Construction phase • Operation phase

• Local • Regional

• Air and water quality monitoring • Noise monitoring • Waste pretreatment • High compaction • Pest species monitoring and control

• Construction phase • Operation phase • Aftercare phase

• Local • Regional

• Population Most of the causes and human indicated for the above health impact elements can directly or indirectly determine adverse health effects, in particular emissions to air, soil and water, noise and traffic.

(Continued)

Table 17.1.3 Example of checklist of the impact elements for the matrix for landfill environmental impact assessments (see Also Andreottola et al., 1989; Pivato, 2011; Pivato et al., 2013; Ranzato et al., 2012; Palmiotto et al., 2014; Yang et al., 2014)dcont'd SOLID WASTE LANDFILLING j Concepts, Processes, Technologies j R. Cossu, R. Stegmann

Impact Elements

Adverse effects on biodiversity in the surrounding environment

Indicators to Quantify the Impact Element

• Variations in population densities of special or protected species

Causes of the Impact Element

Environmental Mitigation and Categories Compensation Measure to Reduce the Impact Affected by the Impact Element Element

• Biodiversity Most of the causes indicated for the above impact elements can directly or indirectly determine adverse effects on biodiversity, in particular emissions to air, soil and water, noise and traffic.

• Improve the connectivity of important nearby ecological units and greenways • Waste pretreatment • Air and water quality monitoring and Noise monitoring seperately

Scale Analysis Temporal Scale

Spatial Scale

• Construction phase • Operation phase • Aftercare phase

• Local • Regional

• Weighting. To achieve a more reasonable and reliable prediction of impacts, it is recommended that the relative importance of each assessment indicator is taken into account. This can be accomplished by assigning weights to the assessment indicators based on the importance attached to them by decision makers. Although the process of weighting is inherently subjective and reflect societal and stakeholder preferences, methods such as the analytic hierarchy process (AHP), which has been utilized in a wide range of decision making areas, can at least provide a viable and rigorous procedure for determining such weights (Saaty, 1980; Wang et al., 2010). • Representation. Considering the difficulty frequently encountered in quantifying the entity of interactions between the various control lists present in each matrix (as described below) and communicating this synthetically and effectively, a chromatic representation, including five colors reflecting positive and negative influences and a neutral (no influence) condition, can be employed to describe the latter in a qualitative form. Two different chromatic scales can be used, corresponding to positive or negative influences and including a total of four assessment levels (expressed by different tonalities) plus a neutral value. The four chromatic tonalities correspond to extremely positive, positive, negative, and extremely negative values; the neutral value can be represented using a neutral color (white) (see Table 17.1.1). The chromatic representation of impact allows decision makers to immediately identify in a visual manner the most critical elements of impact to be assigned priority in the case of mitigation and compensation actions. Evaluation of mitigations and compensations It is virtually impossible to achieve a true zero impact. Accordingly, mitigation and compensation constitute the key steps in EIA. Mitigation may be defined as the measures put in place to avoid, reduce, and, if possible, remedy significant adverse effects of a plan or project, as envisaged, for example, in the European Directive 85/337/EEC. Mitigation actions can target the sources of impact or, alternatively, reduce the exposure that receptors undergo, and be carried out either during a plan or project or following completion. When effective mitigation is impossible, compensation may be provided. Compensation is defined as the replacement of lost (because of adverse environmental impacts) environmental functions and values with equivalent ones, for example, by reconstructing a new habitat if one is destroyed during the creation of a project. Summing up, the evaluation of mitigations and compensation is aimed at: • identifying and assessing measures to avoid, reduce, or remedy the impacts determined previously; • assessing the effectiveness of the above mitigation/compensation measures; and • defining the residual environmental impacts, which are the net impacts remaining even if the mitigation and compensation measures are in place. Evaluation of residual environmental impacts The residual environmental impacts refer to the net environmental impacts remaining after mitigation and compensation, taking into account the background environmental conditions and the impacts from existing, committed, and planned projects.

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Final decision The final decision presents the best alternative, identified as the decision having the lowest residual negative impacts or least overall environmental impact. Viewed from a sustainability perspective, the most acceptable alternative is one that meets international, national, and regional environmental standards while being socially and economically acceptable. Application of the method to sanitary landfills The operative approach for sanitary landfills is represented by a sequence of four matrix schemes that correlate the interactions between the causes of impact, elements of impact, environmental categories, and mitigation/compensation measures over the service life of a landfill. Fig. 17.1.2 shows a block scheme of the method based on the matrices commented in detail in the next paragraphs. The iteration represented in the scheme means that the number of evaluations of residual impact will be equal to the product of the number of projects (N) for the number of sites (M) deemed suitable. All these assessments will subsequently be the object of cross-analysis prior to final decision. The whole scheme will be repeated for each of the life stages of the service’s life cycle of the landfill. Matrix of the causes and elements of impact (Matrix A) The first type of matrix identifies the activities, processes, and features related to plant construction, functioning, and existence underlying the onset of elements of impact (i.e., processes and factors capable of affecting the state of environmental categories, see Table 17.1.3). Since the method should cover all three different phases of a given project (construction, operation, and aftercare phases), three corresponding matrices focusing on the various elements of impact for each phase should be envisaged. The importance of the causes with regard to determination of a specific element of impact is assessed by means of a series of chromatic tonalities. The first matrix permits the clarification of environmental impact of a project or plant, thus allowing the need for improvement to be identified. In the case of more alternative projects to be assessed, this matrix represents a useful tool in establishing a sound background for decision making. Matrix of potential impacts (Matrix B) This matrix presents as control lists the elements of impact, already defined in matrix “A” and environmental categories (see Table 17.1.3). From the intersection of the two lists, potential impacts on the environment arising from landfill construction, operation, and aftercare can be singled out, and the “B” matrix can therefore be used to provide a global, synthetic overview of all potential issues related to the landfill. Indeed, should it be necessary to assess the impact of a particular landfill on various sites, a number of different “B” matrices would be carried out and compared to formulate a judgment as to the most suitable site. Clearly, in this case the diversity of the various “B” matrices should be aligned to the

SOLID WASTE LANDFILLING j Concepts, Processes, Technologies j R. Cossu, R. Stegmann

SCOPE DEFINITION

SCALE ANALYSIS DEFINITION

Plant Characteristic Analysis (N plants)

Impact causes

Impact elements

MATRIX A

Site Characteristic Analysis (M sites)

Impact elements

Environmental categories

MATRIX B

Mitigation and Compensation Analysis

Mitigation measures

Impact elements

MATRIX C

Residual Impact Assessment

Impact elements

Environmental categories

MATRIX D

FINAL DECISION

Figure 17.1.2 Scheme of the environmental impact assessment methodology through chromatic matrices.

different characteristics of the sites, while the “A” matrix remains unchanged since it depends on the intrinsic characteristics of the landfill. Vice versa, if it were necessary to assess the impact of different types of landfill on a single site, the resulting various “B” matrices would be influenced by the corresponding variations in “A” matrices. In the case of a decision dependent on the results of consideration of more than one project based on more than one site, the number of “B” matrices taken into account would increase considerably, as they

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Population and human health

Material assets, cultural heritage and landscape

LANDFILL

Biodiversity

Land, soil, water, air and climate

Figure 17.1.3 The principal environmental categories (factors) affected directly or indirectly by a landfill. The interactions between the categories should be explicitly evaluated to carry out a rigorous environmental impact assessment.

are equal to the combination of all possible cases. Finally, in the case of an already existing single installation, the “B” matrix identifies potential impacts, highlighting those issues towards which monitoring efforts and improvements should be focused. Matrix of mitigations and compensations (Matrix C) The third matrix considers, on the basis of potential negative impact identified in matrix “B”, all the actions to be adopted to eliminate or reduce the negative impacts to acceptable environmental levels, or at least to limit these impacts. When implemented, these actions should impinge on the causes largely contributing to the onset of negative elements of impact; for this reason, identification of the causes should be based on careful evaluation of the “A” matrix. To this regard, two important points should be highlighted. Firstly, the obtaining of a clear picture of all possible interactions is mandatory, as any single element of impact may be influenced by more than one introduced improvement. Moreover, it should not be overlooked that a given same measure may produce simultaneously positive effects on some elements and negative side effects on others. As an example, in the field of sanitary landfilling, a collection system and an on-site treatment process aimed at limiting the impact caused by the presence and uncontrolled emissions of leachate may also produce negative effects such as annoying odors generated in various parts of the treatment plant. Therefore, the overall efficacy of

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the measures should be assessed using the two different chromatic scales (negative and positive) defined previously. Matrix of residual impacts (Matrix D) On the basis of the selected mitigation and compensation measures and their efficacy, evaluated using the “C” matrix, the method provides a fourth matrix to assess residual impacts remaining once the operations of compensation and mitigation have been set up to counteract the various elements of impact. This matrix is analogous to the “B” matrix used for assessment of potential impact although, unlike the latter, examination of the “D” matrix allows us to express a definitive judgment on the degree of compatibility of a landfill with regard to its impact on the surrounding environment. Moreover, the comparison of “B” and “D” matrices allows one to visually appreciate the efficacy of compensation and mitigation measures. FINAL REMARKS The assessment scheme based on the use of chromatic matrices appears to represent a convenient tool for use in assessing the environmental impact of a landfill. The application of this method allows for a careful and systematic identification of all elements of impact to be taken into account, providing a rational organization of the results of the study, and a synthetic and effective graphical representation. The proposed method supports the identification of a solution to the problem of EIA at all levels, particularly as it is clearly comprehensible by both technicians and nonexperts such as decision makers. The assessment scheme illustrated, moreover, presents the advantage of explicitly taking all phases of the life cycle of the landfill into account, some of which are often overlooked but are nonetheless important. In conclusion, this scheme is proposed for use at various levels. A public administration official who has no specific technical knowledge in the field of waste disposal, but who is called upon to express an opinion on an installation (taking environmental, social, economic and political implications into account), gains an immediate and easy understanding of the potential and residual impact on the environment caused by the installation through the “B” and “D” matrices. However, if the reader of the EIA matrices is an expert in the field, by examining the entire series of matrices, he or she will be in a position to determine all the interactions with their corresponding weights, which have led to the final result. Another advantage, of fundamental importance given the impact that public concerns and protests, at times fueled by misinformation, may have on landfill construction, is the possibility afforded by this tool to present the results of the impact study to the public in a simple and easily understandable way.

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