Cerro Tanaro Landfill Life Cycle Assessment (LCA)

Transcription

1 Cerro Tanaro Landfill Life Cycle Assessment (LCA) Life Cycle Assessment of Cerro Tanaro Landfill with and without leachate recirculation LIFE+ 09 ENV/IT/ Bio.Lea.R. Project. Sara Sanfilippo, PhD Martina D Addario, PhD student Bernardo Ruggeri, Prof. 1

2 Table of Contents 1. Overview 2. Methodology 2.1 Impact Categories 2.2 Allocation Criteria 3. Goal And Scope Definition 3.1. Software and database 3.2. Functional Unit 3.3. System Boundaries 4. Lca Inventory 4.1. Description of Cerro Tanaro landfill equipment 4.2. Initial equipment for the traditional landfill 4.3. Additional equipment for leachate recirculation 5. Life Cycle Impact Assessment 5.1. Cerro Tanaro Landfill without leachate recirculation 5.2. Cerro Tanaro Landfill with leachate recirculation 5.3. Comparison 6. Conclusion 7. References 2

3 1. Overview The overall objective of using Life Cycle Assessment (LCA) in the Cerro Tanaro Landfill project is to evaluate environmental impacts related to the whole lifecycle of the landfill with and without leachate recirculation. The analysis will be performed considering standard indicators such as Global Warming Potential, Acidification, Eutrophication, Human Toxicity, Energy Resources. The support of Gaia S.p.a. as partner was important to implement a LCA model based on actual industrial processes and production chains and therefore consistently estimate the impacts. This report considers the LCA of the Cerro Tanaro Landfill, comparing two different cases: 1) standard landfill 2) landfill with leachate recirculation. The description of the characteristics of these cases is presented in a dedicated paragraph. The processes have been deeply investigated on the basis of the available information; a conceptual model for the LCA analysis has been created, paying particular attention to the environmental consequences of the use of electricity, heat, and auxiliary utility consumes (process water, steam,...). 2. Methodology Based on the definition of Life Cycle Assessment (LCA) given by SETAC (Society for Environmental Toxicology and Chemistry, 1991), LCA is a Technique of objective evaluation that allows quantifying environmental loads of a product or process along all life cycle phases, through the systematic measurement of all physical exchanges from and towards the eco-system. Environmental burdens have to include the use of natural resources, as well as generation of waste and release of harmful substances into the eco-system. In general every anthropogenic activity can be generalised by a LCA. Parameters of environmental impacts, must be identified and quantified through a systematic and objective technique in all phases of the life cycle. 3

4 The first definition of LCA given by SETAC in Guidelines for Life-Cycle Assessment: a code practice was implemented by ISO international standard from which the following statement was drawn: LCA studies analyse the environmental aspects and potential impacts throughout the product's life cycle (from-cradle-to-grave) from raw material acquisition, through production, use and disposal (Fig. 1). LCA can therefore address production and consumption of goods towards better standards of human and environmental health, as well as natural resources saving. As it allows an objective and meaningful measurement of the product s eco-profile, LCA methodology is worldwide accepted and appreciated. Figure 1: Life Cycle Assessment (LCA) framework According to ISO (2006), an LCA comprises four major stages: goal and scope definition, life cycle inventory, life cycle impact assessments and interpretation of the results (Fig. 2). 1. The Goal and Scope Definition phase defines the overall objectives, the boundaries of the system under study, the sources of data and the functional unit to which the achieved results refer. 2. The Life Cycle Inventory (LCI) consists of a detailed compilation of all the environmental inputs (material and energy) and outputs (air, water and solid emissions) at each stage of the life cycle. 4

5 3. The Life Cycle Impact Assessment (LCIA) phase aims at quantifying the relative importance of all environmental burdens obtained in the LCI by analysing their influence on selected environmental effects. 4. In the Interpretation phase and improvement, (not mandatory) as the last step of an LCA study, the results from the LCI and LCIA stages must be interpreted in order to find hot spots and compare alternative scenarios. Figure 2: Life Cycle Assessment (LCA) structure according to ISO The LCA approach is currently wide accepted by the scientific basis, to describe several environmental sustainability indicators, as well as a tool for supporting green communication and green marketing instruments. For these reasons, among other methodologies, Life Cycle Assessment (LCA) is increasingly being used as an objective and credible tool to measure the environmental performances of products and understand the environmental sustainability of the production chain. The ISO 14040/44 standards provide the general framework for Life Cycle Assessment. However, the ISO framework leaves the practitioner with a range of choices that can change the results and conclusions of an LCA study and therefore affect its legitimacy. While flexibility is essential in 5

6 responding to the large variety of questions addressed, further guidance is needed to support consistency and quality assurance. For this reason, the Joint Research Centre (JRC) of the European Commission has set up an International Reference Life Cycle Data System (ILCD), which provides a common basis for consistent, robust and quality-assured life cycle data and studies. The ILCD Handbook (available online at ) aims to improve the compatibility and consistency of data generation and reporting requirements, as well as it aims to increase stakeholder acceptance of the tool LCA and its results. Figure 3: The structure of the ILCD Handbook 2.1 Impact categories In order to expose results and make comparisons between different kind of products, categories of impacts and related indicators must be identified. These indicators summarize environmental effects connected with energy and mass flows in input and output from the system. The phase of impact assessment considers the following indicators. These indicators have been chosen within those available in EPD 2008 and TRACI 2: 6

7 Global Energy Requirement (GER) Global Warming (GWP) Ozone Layer Depletion (ODP) Photochemical Oxidation Acidification (AP) Eutrophication (EP) Carcinogenics Non carcinogenics MJ eq kg CO 2 eq kg CFC-11 eq kg C 2 H 4 eq kg SO 2 eq kg PO 3-4 eq kg benzene eq kg toluene eq Table 1: indicators considered with EPD 2008 and TRACI 2. Global Energy Requirement The use of raw materials with energy content will be dealt by calculating the Gross Energy Requirement as the total primary energy extracted from the Earth: GER = Σ (Gross heat content) i * m i Such indicator is obtained by the product of quantities m i of all raw materials with energy content (both non renewable and renewable) by their gross heat value. The GER impact indicator, expressed in MJ, can further be divided according the non renewable (NRER) and renewable (RER) contributions. Global Warming It is caused by the increase of atmospheric temperature following the massive increase of greenhouse gases such as CO 2 and water vapour which are able to absorb the infrared radiation emitted from the Earth. This contributes to global warming and consequently to climate change. The category indicator is the GWP (Global Warming Potential) and the characterization factor is represented by kg of carbon dioxide equivalent; the corresponding quantities of the various greenhouse gases are converted through the global warming potentials (GWP's) in common units of kg of carbon dioxide equivalent. The GWP's are normally calculated for an exposure period of 100 years. Ozone Layer Depletion Ozone is the gas that characterizes the stratosphere and its function is to shield the Earth from ultraviolet rays of the sun, CFCs (chloro-fluoro-carbons) affect the ozone molecules and over time 7

8 have created the well known "Hole". The major consequences of this phenomenon regard especially human health (carcinomas, decrease in immune system function). It is quantified by kg CFC-11 equivalent; the ozone-depleting potential (ODP), that is based on the number of reactions of ozone molecule breakage, is used to standardize the values for the various substances. Photochemical Oxidation It is an environmental effect caused by the presence of unburned hydrocarbons and nitrogen oxides in the flue gases of oil and derivatives. They react with each other in the presence of sunlight and produce ozone (tropospheric level), highly toxic to humans because of the high chemical reactivity. The category indicator is ethylene, to which all the various substances values are related through the photochemical ozone formation potential (POCP). The unit of measurement is the kg of ethylene (C 2 H 4 ) equivalent. Acidification It consists in decrease of the ph of lakes, rivers, forests and soil: this leads to serious consequences for humans and environment. The main causes are emissions from fossil fuels combustion, particularly those with a high content of sulphur. It is expressed in terms of kg of SO 2 equivalent or moles of H + equivalents through the standardization system that considers the acidification potential (AP). Eutrophication The massive injection of substances such as phosphorus and nitrogen causes a decrease of oxygen content in soils and surface water lakes. Effect is evident due to the formation of supernumerary algae. BOD and COD (expressed in kg of O 2 ) represent the measurement units that quantify the oxygen demand necessary to achieve the natural purity. The kg of NO3 - or PO 3-4 equivalent are obtained through the eutrophication potential (NP). Carcinogenics and non carcinogenics The toxicological impacts on both humankind and environment depend on the characteristics of chemical substances and other factors such as the ability to degrade or to accumulate. Since the influence area is local, it is very difficult to quantify the various contributions to the overall effect, which can involve any organism or ecosystem. 8

9 They are expressed respectively in kg of benzene equivalent and in kg of toluene equivalent. Environmental impacts can affect the environment and ecosystems at different scales such as global, local, regional. Table 2 reports the main impact categories and their scale of damage. Environmental Effect Scale Of Influence Resources depletion Global Global warming Global Ozone depletion Global Acidification Regional Eutrophication Regional/local Photochemical smog Regional Human toxicity Regional/local Eco-toxicity Regional/local Waste generation Regional/local Visual impact Local Surface water pollution Local Land use Local Water resources use Local Dust emissions Local Noise / vibrations Local Traffic Local Table 2: main impact categories with their scale of damage. Results can be supplied as midpoint indicators or can be converted into damage indicators. Both midpoint and endpoint indicators can be normalised to the per capita yearly impacts of one European citizen, thus expressing the results as person-year equivalents. After normalisation, indicators might be added up using the default weighting factor (all weights = 1) or other sociallydriven weighting values. In Fig. 4, the mid-point categories reside in the centre of the figure and are linked on the right to attributes, which are in turn linked to the life cycle stages. On the left, mid-point categories are aggregated into damage categories, which are then aggregated into a single score index. The midpoint category values are created through classification and characterisation of the inventory of 9

10 attributes, an objective process. Conversely, some form of subjective weighting (w1-w4) is required to calculate the damage category and single score index values. Figure 4: correlation of ecological impacts to LCA considering impact categories. The model used for indicators calculation is CML 1992, modified in accord to the IFEU report (2005),in order to consider only the relevant impacts categories for base oil. Furthermore the system have been analysed with Ecoindicator method, that gives results making an aggregation of impacts. 2.2 Allocation criteria A process providing more than one function, is called multifunctional and usually its output comprises more than one single product. Moreover, raw material inputs often include intermediate or discarded products. 10

11 An appropriate decision must therefore be made as to which of the economic flows and environmental impacts associated with the product system under study are to be allocated to that system. Allocation, or partitioning, solves the multifunctionality by splitting up the amounts of the individual inputs and outputs between the co-functions according to some allocation criterion, being a property of the co-functions (e.g. element content, energy content, mass, market price etc.). Figure 5: Allocation or partitioning operations in LCA framework (Badino, 1998). The environmental burdens must be assigned to all economic valuable product, that imply that industrial rejects are not claimed to be responsible of any environmental load (this latter has to be discuss while dealing with recycling). To assign environmental loads in the right proportion, different criteria can be chosen. On the basis of the exact knowledge of the industrial system under study, allocation can be performed according to physical criteria such as mass or volume or energy. 11

12 Normally, physical allocation must be preferred to economic allocation due to the fact that environmental loads are associated to industrial operations and use of materials and energy, and these are not forcedly connected to the formation of economic value of products. In any case ISO supplies guidelines on allocation criteria. According to ISO 14041, wherever possible, allocation should be avoided by: - dividing the unit process to be allocated into two or more sub-processes and collecting the input and output data related to these sub-processes; - expanding the product system to include the additional functions related to the co-products. Where allocation cannot be avoided, the inputs and outputs of the system should be partitioned between its different products or functions in a way which reflects the underlying physical relationships between them. This allocation will not necessarily be in proportion to any simple measurement such as the mass or molar flows of co-products. Finally, where physical relationship alone cannot be used for allocation, the inputs should be allocated between co-products and functions on the basis of other relationships between them, such as the economic value of the products. 3. Goal and scope definition The goal of the analysis is to define the energy and environmental burdens associated to the whole lifecycle of the Cerro Tanaro landfill, and to make a comparison between two cases: with and without leachate recirculation Software and database The softwer SimaPro 7.2 is used in order to perform the present study. Primary data are collected from Gaia S.p.a., while secondary data are derived from databases, particularly Ecoinvent v Functional Unit Functional unit is the reference unit, to which environmental indicators are associated. In this study the unit chosen is: 1 MJ of produced energy by the Cerro Tanaro landfill as biogas. 12

13 3.3. System Boundaries The definition of system boundaries of the study is one of the most important step of a LCA. This report provides the eco-profile of the base, starting from the extraction raw materials, until the gas production by the Cerro Tanaro landfill. Spatial boundaries correspond to the landfill plant: waste collection, waste recycling, pre-treatments and waste transportation till the landfill are not considered, because they have the same impact in both cases, with and without leachate recirculation. Spatial boundaries cover the landfill plant till the biogas production, and this value changes in the two cases. In the standard Cerro Tanaro Landfill data on biogas production are provided by Gaia S.p.a. as experimental data obtained directly from the landfill, and extrapolated in 25 years of the plant life. In the Cerro Tanaro landfill with leachate recirculation data on biogas production are partially provided by Gaia S.p.a. as experimental data obtained directly from the landfill and partially evaluated through laboratory experiments; these data are extrapolated for the duration of the plant life. Actually the hypothesis are, in comparison with the standard landfill: increase of the biogas production equal to the 30% and a decrease of the plant life of the 30%. Temporary boundaries are 25 years for the standard landfill, and 17.5 years for the landfill with leachate recirculation. 4. Lca Inventory Life Cycle Inventory (LCI) analysis involves creating an inventory of flows from and to nature for a product system. Inventory flows include inputs of water, energy, and raw materials, and releases to air, land, and water. To develop the inventory, a flow model of the technical system is constructed using data on inputs and outputs. The input and output data needed for the construction of the model are collected for all activities within the system boundary. Next paragraphs present in detail the flow models and the inputs of the Cerro Tanaro landfill. 13

14 Figure 6: Life Cycle Inventory model Description of Cerro Tanaro landfill equipment The landfill for non-hazardous waste in Cerro Tanaro (Asti, Italy) is active from the end of 2003 and it is part of the integrated waste management system managed by GAIA S.p.A.. The waste comes from the refuses of other processes or plants, which cannot be recovered in other ways, in particular: - organic waste after mechanical-biological pre-treatment; - refuses from plastic and other fractions of separate collection; - refuses from composting plant (plastic films); - sand from street sweeping; - cemetery waste; - non-hazardous waste from other treatment plants outside Asti province. The material landfilled has a moderate quantity of organic matter and a little moisture content; therefore waste biodegradation takes longer times. This results in a less efficient energy recovery and higher post-management care costs. The choice of managing the landfill as a bioreactor was adopted in order to better exploit the present biomass and optimize biogas production. In 2010 Bio.Lea.R. project was approved in the frame of Life+ program, and additional interventions were made in order to transform the landfill as a bioreactor. The interventions regarded three main systems: (i) biogas extraction and treatment plant, (ii) injection plant and (iii) monitoring system for data collection. 14

15 CERRO TANARO LANDFILL LCA The landfill is built with two hydraulically independent cells (Figure 7), A and B, respectively with a volume of 360,000 m3 and 300,000 m3. Cell A is managed as bioreactor, while cell B is still managed conventionally as comparison term. A description of the initial equipment of the landfill will be presented, followed by the additional intervention made for Bio.Lea.R. project. Figure 7: View of Cerro Tanaro landfill during the initial management phases Initial equipment for the traditional landfill Every landfill should reduce the waste impact on the surrounding soil, surface water, groundwater and atmosphere. The conventional landfill, thought as a dry tomb, has to guarantee the isolation of the waste from the bottom to the top of the landfill body. The two cells of Cerro Tanaro landfill are equipped with a geological water-resistant barrier both on the bottom and on the sides, consisting of a layer of compacted clay (1 meter) and a geomembrane of HDPE as sealing barrier (Figure 8). The refuses are disposed on a 50 cm layer of gravel for leachate drainage. This drainage layer channels the leachate towards the pumping system. The landfill is equipped with collection and extraction wells for the leachate collected on the Figure 8: Views of the bottom and the sides of Cerro Tanaro landfill before disposal. bottom. In each well there is a submerged electrical pump. The leachate is then sent into 8 15

16 fiberglass storage tanks, each of 50 m3 volume for a total storage volume of 400 m3 (Figure 9). Leachate is collected by the service for transport and disposal to the treatment plant. Figure 9: Storage tanks for leachate collection. Figure 10: Regulation station SRA. During the disposal phase, 8 extraction wells for LFG collection were settled, consisting in metal wire baskets filled with gravel and an axial HDPE fissured pipes. Each well is raised during the landfilling, until it can reach the final height. At the beginning the biogas was burned directly at the top of each well in local flares. Then a temporary network for biogas collection was built. LFG is connected to two regulation stations, called SRA and SRB (Figure 10). Moreover, along the perimeter of the landfill, 5 drains for biogas extractions were inserted between the water-resistant geomembrane and the waste mass. The drains are connected to the same regulation stations. Figure 11 shows the positions of the extraction wells, the drains and the regulation stations. Figure 11: Initial collection system: the violet dots represent the extraction wells, the green points are the side drains, SRA and SRB are the regulation stations. 16

17 The regulation stations are collected in parallel to a central extraction and combustion station (CE), showed in Figure 12. It consists in a high temperature adiabatic flare (>850 C). The aim of the CE is to extract the biogas collected from the network and send it with a light pressure to the flare. This equipment can manage 250 Nm3/h of LFG. The thermal power of the combustor is 1200 kwt. Figure 12: Central extraction and combustion station (CE) Additional equipment for leachate recirculation The initial layout of Cerro Tanaro landfill needed new installations in order to transform it into a bioreactor with leachate recirculation. The main additional equipment regarded 3 systems: (i) biogas extraction and treatment plant; (ii) recirculation and injection plant; (iii) monitoring system for data collection. (i) The enhancement of the energy recovery regarded the installation of a central energy recovery station (CRE), in parallel with the existing CE. Its aim is to transform the biogas thermic potential in electricity. The new system is independent from the CE, because it is equipped with its own aspirator, able to Figure 13: Energy recovery station, CRE. replace completely the other one. The CRE (Figure 13) consists in an electrical generator with an engine with nominal power of 330 kw, electric efficiency of 37% and nominal capacity of 186 Nm3/h. Before reaching the engine, the biogas is pre-treated through forced dehumidification in a chiller. The CRE is also equipped with a gas analyser that monitors the composition of the biogas coming from each well. Figure 14 displays a functional scheme of the CRE, including the three sections of extraction, gas treatment and energy recovery. The existing flare is in parallel with the 17

18 CRE, because, if CRE is not working or in case of emergency, the biogas can be directly burned. Figure 14: Functional scheme of CRE. Apart from the CRE, also the biogas extraction network was enhanced: the wells in cell A reached a total number of 26, compared to the existing 8. Moreover, 8 extraction rings (10 m diameter) were installed around the wells intended for leachate recirculation, on the top of the landfill. (ii) The injection system consists of: a pressurization equipment for leachate or waste water recirculation, 4 vertical injection wells, 8 pierced ring pipes around 8 biogas extraction wells (20 m diameter) and 8 pierced horizontal pipes Figure15: Particular of the injection 18

19 (10 m lenght). The 8 sub-irrigation rings are placed below the final cover, at the centre of the landfill in order to avoid leakage on the sides. The additional horizontal pipes cover the areas not reached by the rings and they are placed at 1-2 m depth. All the injection system is manually adjusted. The pump for leachate recirculation send the liquid to a regulation station (Figure 16) placed near the SRA. From the regulation station the leachate can be sent to one or more irrigation pipes. The characteristic parameters of the pump are: design flow rate 7 m3/h; operational flow rate 5 m3/h; head 25 m. (iii) The monitoring system for data collection mainly consists in temperature probes, electric resistivity probes and a database for remote control of the monitoring points and data recording (WEB-GIS system). The measurement of the electric resistivity allows to monitor the liquid distribution into the landfill during the recirculation. Moreover, an infra-red camera controls the biogas pipes status, according to the temperature dislplayed. After the landfill capping was completed, a monitoring room was installed at the top of the landfill (Figure 17), where a computer connected to the monitoring instruments is used for data recording. Figure 16: Regulation station for leachate recircualtion, equipped with flow rate meter. Figure 17: Particulars of the monitoring room for data recording. 19

20 The recirculation system is running since January 2014, on one single irrigation ring with a rate flow of 5 m3/h, 8 hours per day. Figure 18 shows the layout of cell A of Cerro Tanaro landfill, where the gas extraction wells, the irrigation pipes and the external equipment are placed. Figure 18: Layout of cell A: -the green circles are the sub-irrigation rings; -the yellow lines are the horizontal irrigation pipes; -the blue points are the additional gas extraction wells; -the points named V are the existing gas extraction wells; -CE is the existing combustion station; -CRE is the new energy recovery station. 20

21 5. Life Cycle Impact Assessment This chapter presents an overview of the impacts of to the whole lifecycle of the Cerro Tanaro landfill, and the comparison between two cases: with and without leachate recirculation. Each paragraph starts with a table showing the energy and environmental loads. Than each impact is analyzed in detail in a quantized flow sheet of the process: the arrows thickness is proportional to the impact flow that represents. Each box is quantified with a percent valued Standard Cerro Tanaro Landfill Global Energy Requirement (GER) MJ eq Global Warming (GWP) kg CO 2 eq Ozone Layer Depletion (ODP) kg CFC-11 eq 2.18E-11 Photochemical Oxidation (POCP) kg C 2 H 4 eq 1.96E-07 Acidification (AP) kg SO 2 eq 7.84E-07 Eutrophication (EP) kg PO 3-4 eq 6.48E-07 Carcinogenics kg benzene eq Non carcinogenics kg toluene eq 3.81 Table 3: Results of the Life Cycle Assessment of the standard Cerro Tanaro Landfill; Functional Unit=1MJ. Figure 19: Flow sheet with GER results expressed in MJ eq (cut-off 2.5%); Functional Unit=1MJ. 21

22 Figure 20: Flow sheet with GWP results expressed in kg CO 2 eq (cut-off 0.89%); Functional Unit=1MJ. Figure 21: Flow sheet with ODP results expressed in kg CFC-11 eq (cut-off 2.2%); Functional Unit=1MJ. 22

23 Figure 22: Flow sheet with POCP results expressed in kg C 2 H 4 eq (cut-off 2.2%); Functional Unit=1MJ. Figure 23: Flow sheet with AP results expressed in kg SO 2 eq (cut-off 2.2%); Functional Unit=1MJ. 23

24 Figure 24: Flow sheet with EP results expressed in kg PO 4 3- eq (cut-off 0.85%); Functional Unit=1MJ. Figure 25: Flow sheet with Carcinogenics results expressed in kg benzene eq (cut-off 5%); Functional Unit=1MJ. 24

25 Figure 26: Flow sheet with Non Carcinogenics results expressed in kg toluene eq (cut-off 2.5%); Functional Unit=1MJ Cerro Tanaro Landfill with leachate recirculation Global Energy Requirement (GER) MJ eq Global Warming (GWP) kg CO 2 eq Ozone Layer Depletion (ODP) kg CFC-11 eq 1.82E-11 Photochemical Oxidation (POCP) kg C 2 H 4 eq 1.65E-07 Acidification (AP) kg SO 2 eq 6.77E-07 Eutrophication (EP) kg PO 3-4 eq 1.29E-07 Carcinogenics kg benzene eq Non carcinogenics kg toluene eq 1.8 Table 4: Results of the Life Cycle Assessment of the Cerro Tanaro Landfill with leachate recirculation; Functional Unit=1MJ. 25

26 Figure 27: Flow sheet with GER results expressed in MJ eq (cut-off 4.2%); Functional Unit=1MJ. Figure 28: Flow sheet with GWP results expressed in kg CO 2 eq (cut-off 0.84%); Functional Unit=1MJ. 26

27 Figure 29: Flow sheet with ODP results expressed in kg CFC-11 eq (cut-off 2.3%); Functional Unit=1MJ. Figure 30: Flow sheet with POCP results expressed in kg C 2 H 4 eq (cut-off 3.2%); Functional Unit=1MJ. 27

28 Figure 31: Flow sheet with AP results expressed in kg SO 2 eq (cut-off 3.2%); Functional Unit=1MJ. Figure 32: Flow sheet with EP results expressed in kg PO 4 3- eq (cut-off 3.8%); Functional Unit=1MJ. 28

29 Figure 33: Flow sheet with Carcinogenics results expressed in kg benzene eq (cut-off 5%); Functional Unit=1MJ. Figure 34: Flow sheet with Non Carcinogenics results expressed in kg toluene eq (cut-off 5%); Functional Unit=1MJ. 29

30 5.3. Comparison This paragraph aims to make a comparison among all the results that have been presented previously. Table 5 is a summary of all impact value results. Table 6 shows the same results of Table 5 but referred to the reference case, so values are percentage. All the values are lower than 1, this means that the prototypes have better results than the classical heat exchanger. Global Energy Requirement (GER) MJ eq Standard CT Landfill CT Landfill with leachate recirculation Global Warming (GWP) kg CO2 eq Ozone Layer Depletion (ODP) Photochemical Oxidation (POCP) kg CFC-11 eq kg C2H4 eq 2.18E E E E-07 Acidification (AP) kg SO2 eq 7.84E E-07 Eutrophication (EP) kg PO 4 3- eq 6.48E E-07 Carcinogenics kg benzene eq Non carcinogenics kg toluene eq Table 5: Results comparison; Functional Unit=1MJ. Standard CT Landfill Global Energy Requirement (GER) % 1 Global Warming (GWP) % 1 Ozone Layer Depletion (ODP) % 1 Photochemical Oxidation (POCP) % 1 Acidification (AP) % 1 Eutrophication (EP) % 1 Carcinogenics % 1 Non carcinogenics % 1 CT Landfill with leachate recirculation Table 6: Results comparison expressed in %; Functional Unit=1MJ. 30

31 % 1 0,9 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,1 0 GER GWP ODP POCP AP EP Carc Non carc CT standard CT with leachate recirculation Figure 35: Results comparison expressed in %; Functional Unit=1MJ. Another method has been used to show results with aggregated indicators: the Ecoindicator method (Figure 36). In general the results of the comparison support the results of the characterization carried out in the previous paragraphs. Figure 36: End point impacts of Cerro Tanaro landfill with and without leachate recirculation (Eco-indicator 99). 31

32 6. Conclusion The state of the art of the LCA within the Cerro Tanaro landfill project has been presented in this report. A Life Cycle Assessment from cradle to grave, concerning two different cases has been developed and modelled: with and without leachate recirculation. The leachate recirculation appears to be a good chance to improve a well know technology, as landfill is, using a scientific innovation. 7. References 1. Ecoinvent. Life Cycle Inventories of chemicals data v 2.0, ILCD database. ( 3. EIPPC. European Integrated Pollution Prevention and Control, CML Centre for Environmental Studies (CML), University of Leiden ILCD database. ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance. 32