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MASSA Spin-off – Riduzione dei rischi ambientali.

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1 MASSA Spin-off – Riduzione dei rischi ambientali

2 MASSA Spin-off – Riduzione dei rischi ambientali Atualmente é uma das maiores organizaçoes de pesquisa e formaçao superior na Itália, com docentes e pesquisadores, mais de doutorandos de pesquisa e estudantes. Universidade de Florença

3 MASSA Spin-off – Riduzione dei rischi ambientali Conselho Nacional de Pesquisas CNR Ente público nacional responsável pela produçao, promoçao, difusao, transferência e valorizaçao das atividades de pesquisa e respectivas aplicaçoes para o desenvolvimento do país. 11 Departamentos Mais de 100 Institutos

4 MASSA Spin-off – Riduzione dei rischi ambientali M.A.S.S.A. Spin-off Metodologias e Aplicações Científicas para a Salvaguarda Ambiental  Oferecer soluçoes para mitigaçao dos impactos ambientais. MONITORAMENTO DE RISCOS CNR – Conselho Nacional de Pesquisas UNIFI – Universidade de Florença Parceiros Industriais Sócios Privados MASSA Spin-off

5 MASSA Spin-off – Riduzione dei rischi ambientali European directive Member States shall take appropriate measures to encourage: (a) firstly, the prevention or reduction of waste production and its harmfulness, (b) secondly: - the recovery of waste by means of recycling, reuse or reclamation or any other process with a view to extracting secondary raw materials, or - the use of waste as a source of energy.

6 MASSA Spin-off – Riduzione dei rischi ambientali Waste hierarchy Reduce Reuse Recycle Energy Recovery Landfilling

7 MASSA Spin-off – Riduzione dei rischi ambientali Landfills The European Union has laid down strict requirements for landfills to prevent and reduce as far as possible the negative effects on the environment, specifically on surface water, groundwater, soil, air and human health. Stringent operational and technical requirements on the waste and landfills

8 MASSA Spin-off – Riduzione dei rischi ambientali Municipal waste production

9 MASSA Spin-off – Riduzione dei rischi ambientali Municipal waste recycled

10 MASSA Spin-off – Riduzione dei rischi ambientali Municipal waste incinerated

11 MASSA Spin-off – Riduzione dei rischi ambientali Landfills are still present

12 MASSA Spin-off – Riduzione dei rischi ambientali Municipal waste landfilled

13 MASSA Spin-off – Riduzione dei rischi ambientali Even if people don’t like them…

14 MASSA Spin-off – Riduzione dei rischi ambientali …Sanitary landfills are much better then uncontrolled disposal

15 MASSA Spin-off – Riduzione dei rischi ambientali CONTROL AND MONITORING PROCEDURES IN OPERATION AND AFTER-CARE PHASES To be carried out in order to verify: that the waste accepted to disposal meets the criterias established for the landfill category, that the processes undertaken within the landfill are correct, that the environmental protection systems function fully as intended, that the permit conditions for the landfill are fulfilled.

16 MASSA Spin-off – Riduzione dei rischi ambientali How is a landfill made…

17 MASSA Spin-off – Riduzione dei rischi ambientali Technical features 3 type of landfills (a) excavated trench (b) area(c) canyon/depression (b)(c)

18 MASSA Spin-off – Riduzione dei rischi ambientali Municipal waste degradation produce leachate and biogas, main landifill vectors of environmental pollution. Leachate Liquid mixture caused mainly by water percolating through waste deposited in a landfill. Once in contact with decomposing solid waste, the percolating water becomes contaminated. Leachate Liquid mixture caused mainly by water percolating through waste deposited in a landfill. Once in contact with decomposing solid waste, the percolating water becomes contaminated. Biogas Gas produced by the biological breakdown of organic matter. Biogas comprises primarily methane (CH4) and carbon dioxide (CO2). Biogas Gas produced by the biological breakdown of organic matter. Biogas comprises primarily methane (CH4) and carbon dioxide (CO2). Chemical, Physical and Biological processes inside municipal landfill

19 MASSA Spin-off – Riduzione dei rischi ambientali Existing site drainage must be modified to route any runoff away from the area. Preparation of the site for landfilling Excavation and preparation of the landfill bottom and subsurface sides. Geomembrane liners are installed.

20 MASSA Spin-off – Riduzione dei rischi ambientali Leacheate collection and extraction facilities are placed within or on the top of the liner. Preparation of the site for landfilling Horizontal gas recovers trenches may be installed at the bottom of the landfill. Before the fill operation begins, a soil berm in constructed at the downwind side of the planned fill area. The berm serves as a windbreak to control blowing materials and as a face against which the waste can be compacted

21 MASSA Spin-off – Riduzione dei rischi ambientali Preparation of the site for landfilling

22 MASSA Spin-off – Riduzione dei rischi ambientali

23 MASSA Spin-off – Riduzione dei rischi ambientali Phase I. Initial adjustment phase The organic biodegradable components in MSW undergo microbial decomposition as they are placed in a landfill and soon after. Biological composition occurs under aerobic conditions, because a certain amount of air is trapped within the landfill. The principal source of microrganisms is the soil material used as a daily and final cover. Digested wastewater sludges and recycled leachate are other sources of organisms.

24 MASSA Spin-off – Riduzione dei rischi ambientali Phase II – Transition phase Oxygen is deplated and anaerobic conditions begin to develop. Nitrate and sulphate are often reduced to nitrogen gas and hydrogen sulphide. The onset of anaerobic conditions can be monitored by measuring the oxidation/reduction potential of waste. The pH of leachate starts to drop due to the presence of organic acids and the effect of high CO 2 concentrations within the landfill.

25 MASSA Spin-off – Riduzione dei rischi ambientali Phase III: Acid phase First step: Enzyme mediated transformation (hydrolis) of higher molecular mass compunds (lipids, polysaccharides, proteins and nucleic acids) into compounds suitable for use by microrganisms as a source of energy and cell carbon; Second step: Microbial conversion of the compounds resulting from the first step into lower molecular mass intermediate compounds (typified by acetic acid: CH 3 COOH). Carbon dioxide is the principal gas generated. The pH of the leachate will often drop to a value of 5 and lower. The BOD and COD and the conductivity of the leachate will encrease significantly. If leachate is not recycled, the essential nutrients will be lost from the system.

26 MASSA Spin-off – Riduzione dei rischi ambientali Phase IV: methane fermentation phase A second group of microrganisms which converts the acetic acid and hydrogen gas to CH 4 and CO 2, becomes predominant. They are identified as methanogens or methane formers. The pH will rise to more neutral values in the range of 6.8 to 8. The COD and conductivity value of the leachate will be reduced. With higher pH values, fewer inorganic constituents can remain in solution.

27 MASSA Spin-off – Riduzione dei rischi ambientali Phase V: Maturation phase The maturation phase occurs after the readily available biodegradable organic material has been converted to CH 4 and CO 2. The rate of landfill gas generation diminishes significantly. The substrates that remain in the landfill are slowly biodegradable. During maturation phase, the leachate will often contain humic and fulvic acids, which are difficult to process further biologically.

28 MASSA Spin-off – Riduzione dei rischi ambientali

29 MASSA Spin-off – Riduzione dei rischi ambientali Quality and quantity of biogas and leachate result from numerous elements Environmental characteristics Rainfall Air temperature Air Umidity Wind Environmental characteristics Rainfall Air temperature Air Umidity Wind Waste characteristics Density Pre-treatments Waste Umidity Waste product analysis Waste granulometry Waste characteristics Density Pre-treatments Waste Umidity Waste product analysis Waste granulometry Landfill Type and geometry Coverage materials Biogas and leachate drainage techniques Landfill Type and geometry Coverage materials Biogas and leachate drainage techniques

30 MASSA Spin-off – Riduzione dei rischi ambientali Typical constituents found in MSW landfill gas ComponentPercent (dry volume) Methane45-60 Carbon dioxide40-60 Nitrogen2-5 Oxygen Sulfides, Disulfides, Mercaptans, etc Ammonia Hydrogen0-0.2 Carbon monoxide0-0.2 Trace constituents

31 MASSA Spin-off – Riduzione dei rischi ambientali Typical data (mg/l) on the composition of leachate ConstituentNew landfill (<2 years) Mature landfill (> 10 years) BOD COD TSS Organic Nitrogen Nitrate2510 Total phoshorous3010 Alkalinity as CaCO pH67 Chloride The presence of trace compounds (some of which may pose high health risks) will depend on the concentration of these in the gas phase within the landfill

32 MASSA Spin-off – Riduzione dei rischi ambientali Biogas and Leachate control Biogas – It is necessary to monitor diffusion from the capping system in order to identify the more critical areas. Leachate – It is necessary to verify the risk of groundwater pollution due to leakages. Biogas – It is necessary to monitor diffusion from the capping system in order to identify the more critical areas. Leachate – It is necessary to verify the risk of groundwater pollution due to leakages.

33 MASSA Spin-off – Riduzione dei rischi ambientali Leachate monitoring

34 MASSA Spin-off – Riduzione dei rischi ambientali Chemical parameters to be controlled Italian Law requires: pH, Temperature, Conductivity, Oxidability (Kubel), BOD 5, TOC, COD, Ca, Na, K, Chlorides, Sulphates, Fluorides, IPA, Metals, Cyanides, Nitrogen compounds, Organoalogen compounds, Pesticides, Phenols, Solvents. Italian Law requires: pH, Temperature, Conductivity, Oxidability (Kubel), BOD 5, TOC, COD, Ca, Na, K, Chlorides, Sulphates, Fluorides, IPA, Metals, Cyanides, Nitrogen compounds, Organoalogen compounds, Pesticides, Phenols, Solvents. Often what Regulations ask is not sufficient to identify a possible dangerous mixing between natural water and leachate.

35 MASSA Spin-off – Riduzione dei rischi ambientali Isotopes Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation of the atom as a particular element. The number of nucleons (protons and neutrons) in the nucleus, known as the mass number, is not the same for two isotopes of any element. For example, hydrogen-1, hydrogen-2 (Deuterium) and hydrogen-3 (Tritium) are three isotopes of the element hydrogen with mass numbers 1, 2 and 3 respectively. The atomic number of nitrogen is 1 (every hydrogen atom has 1 proton); therefore the neutron numbers in these isotopes are 0, 1 and 2 respectively.

36 MASSA Spin-off – Riduzione dei rischi ambientali Leachate isotopic monitoring Leachate and Natural water have different isotopic characteristics, which can led to different concentrantions of some species by more than 2 orders of magnitude. In a landfill monitoring system, isotopes can be used a tracer of water pollution due to leachate mixing.

37 MASSA Spin-off – Riduzione dei rischi ambientali Isotopic ratio as regards a standard in term of ‰ (per mil)  ‰ = [ (Rcp/Rst) –1 ]*1000 Rcp and Rst are isotopic ratios ( 18 O/ 16 O, 2 H/ 1 H). Rcp refers to the sample while Rst refers to the standard V-SMOW (Vienna Standard Mean Ocean Water). 18 O/ 16 O 2 H/ 1 H Isotopic contents of hydrogen radioactived ( 3 H). It is expressed in term of absolute concentrantion U.T. (Tritium Unitiy; 1 U.T. is equivalent to one atom of 3 H for every atoms of H, equivalent to a radioactiviy of 0,12 Bq/l). 3 H/H 13 C/ 12 C Isotopic ratio of dissolved inorganic carbon (DIC). It is expressed in term of ‰ as to the standard PDB (Pee Dee Belemnitella, South Carolina/USA carbonatic rock) Principal isotopic parameters

38 MASSA Spin-off – Riduzione dei rischi ambientali Craig, 1961 – con modifiche WORLD RAINFALL LINEAR REGRESSION

39 MASSA Spin-off – Riduzione dei rischi ambientali 2 H and 18 O COMPARISON BETWEEN RAINFALL WATER AND LEACHATE LEACHATES COMING FROM ANAEROBIC DEGRADATED ORGANIC WASTE WORLD RAINFALL LINE MEDITERRANEAN RAINFALL LINE MEDITERRANEAN RAINFALL LINE

40 MASSA Spin-off – Riduzione dei rischi ambientali Concentration of TRITIUM ( 3 H) in Italian rainfall water

41 MASSA Spin-off – Riduzione dei rischi ambientali LANDFILL LEACHATE 3 H CONCENTRATION FREQUENTLY RANGES FROM 200 AND 1500 U.T. SOMETIMES IT CAN ACHIEVE MORE THAN 3000 U.T. Concentration of TRITIUM ( 3 H) in Italian rainfall water

42 MASSA Spin-off – Riduzione dei rischi ambientali THIS CLEAR DIFFERENCE ALLOW TO FIND OUT LOW WATER CONTAMINATION FROM LEACHATE (EVEN LESS 1% OF LEACHATE) LANDFILL LEACHATE 3 H CONCENTRATION FREQUENTLY RANGE FROM 200 AND 1500 U.T. SOMETIMES IT CAN ACHIEVE MORE THAN 3000 U.T. Concentration of TRITIUM ( 3 H) in Italian rainfall water

43 MASSA Spin-off – Riduzione dei rischi ambientali TRITIUM versus CHLORIDES LEACHATE GROUNWATER SAMPLE POTENTIAL MIXING CURVES

44 MASSA Spin-off – Riduzione dei rischi ambientali  13 C‰ LEACHATE Range from +15 and +30 LEACHATE Range from +15 and +30 GROUNDWATER Range from - 25 and 0 GROUNDWATER Range from - 25 and 0 CARBON ISOTOPE

45 MASSA Spin-off – Riduzione dei rischi ambientali OTHER ISOTOPES PARAMETERS  34 S‰ of dissolved sulphate LEACHATE Frequently around +8 GROUNDWATER Range from - 21 and - 8  18 O‰ of dissolved sulphate LEACHATE Frequently around +27 GROUNDWATER Range from - 0,20 and +11,40

46 MASSA Spin-off – Riduzione dei rischi ambientali Biogas monitoring

47 MASSA Spin-off – Riduzione dei rischi ambientali It is really important to identify and quantify the biogas sources inside a landfill: Diffuse sources from the coverage Gas extraction wells Biogas flares Biofilters Air pollution control A relevant part of the biogas could be diffused into the atmosphere.

48 MASSA Spin-off – Riduzione dei rischi ambientali The CNR worked out a system to monitor gas flux from landfill coverage on the basis of the experience used to monitor gas emission from volcanic and geothermal areas. Monitoring biogas diffusion from coverage

49 MASSA Spin-off – Riduzione dei rischi ambientali The gas transport phenomenon through the soil are mainly ruled by two different mechanisms: diffusion and advection. In the geological literature these two factors are referred to the Fick (diffusion) and to the Darcy (advection) laws.  Diffusion phenomenon are due to concentration gradients. In a porous media, the diffusion process in a direction is described by Fick’s first law: Fd = -K d (dc/dx) Fd is the diffusion velocity in a surface unit (moli/cm 2 sec), K is the porosity coefficient, d is the diffusion coefficient (cm 2 /sec) and dc/dx is the concentration gradient in x direction.  Advective motions are due to pressure gradients and are described by the Darcy law: Fc = - (K/µ) (dp/dx) Fc is the specific flow (cm/sec), K is the permeability coefficient expressed as Darcy units [1Darcy=1cm 2 /(sec atm)], µ is the gas viscosity in centipoise and dp/dx the concentration gradient in x direction. Physical laws: diffusion and advection

50 MASSA Spin-off – Riduzione dei rischi ambientali The estimation of the total amount of gas discharged at the soil-air interface can be obtained by well distributed punctual flux measurements carried out on all the investigated area. Anyway there are a lot of problems concerning the single measurement depending on the reliability of the measuring system, the influence of the meteorological parameters (atmospheric pressure, temperature, relative humidity), on the characteristics of the monitored soil (moist content, presence of fracture). Finally the choice of the right data treatment can make the difference between reliable results and quite pure fantasy. How to estimate the total emission

51 MASSA Spin-off – Riduzione dei rischi ambientali There are various different systems to get soil gas flux measurements. The principal developed techniques can be divided in three main categories: i.Measurements of the gas concentration gradient ii.Micro-meteorological techniques (e.g. eddy correlation) iii.Enclosure based techniques (static and dynamic accumulation chamber) The accumulation chamber method is commonly considered superior to other techniques such as those based on the dynamic concentration, in situ gas concentration measurements at different depths, tracer gas, and eddy correlation. Furthermore, Trégourès et al. (1999) demonstrated that the accumulation chamber method is less dependent on meteorological conditions compared to the other methodologies. Measurement techniques

52 MASSA Spin-off – Riduzione dei rischi ambientali The accumulation chamber method The device developed by CNR, consists of an accumulation chamber, two IR spectrophotometers to measure CO 2 and CH 4 concentrations, a PID (Photoionization detectors) sensor for VOC and a electro- chemical sensor for H 2 S. The system is completed by an analogical-digital converter, a palmtop computer, and a Global Positioning System (GPS). The gas flux is proportional to the slope of the straight line fitting the concentration versus time curve. Soil Surface

53 MASSA Spin-off – Riduzione dei rischi ambientali The measurements made on site, are referred to the slope of the straight line fitting the concentration versus time curve. This data, expressed in ppm/sec (or ppb/sec) units, are correlated to the specific flux (e.g. mol/m 2 day) of every analyzed gas, by mean of calibration curves. Laboratory tests have to be performed before each survey in order to get these calibration curves. Accumulation chamber: calibration

54 MASSA Spin-off – Riduzione dei rischi ambientali Although the accumulation chamber method is less dependent on meteorological conditions, compared to the other methodologies, some parameters may have an influence on the gas emission at soil-air interface. To avoid or minimize these effects, it’s important to carry out the investigations in steady dry weather period and completing each flux survey in few working days. Moreover it’s important to keep under control the atmospheric pressure and the influence of its variations with additional measurements repeated on the same site during all the survey period. Accumulation chamber: field measurements

55 MASSA Spin-off – Riduzione dei rischi ambientali The right sampling grid To choose the proper sampling grid it’s important to have information about the spatial characteristic of the studied phenomenon. In some case auxiliary analysis can give a help to get the right dimensioning of sampling array. For example in landfill biogas emission monitoring, a preliminary infrared thermographic survey can be useful to understand the areal extension of anomalous degassing zones. Typically, in environmental applications, the sampling mesh varies from 10 to 30 m (1 measure every 100 m 2 to 1 every 900 m 2 ). The total number of measurements is usually greater than (up to 1000)

56 MASSA Spin-off – Riduzione dei rischi ambientali The sampling grid

57 MASSA Spin-off – Riduzione dei rischi ambientali We have already seen that to get reliable estimations of global gas emission, large datasets are needed. The bigger is the number of measurements, the more trustworthy the evaluations are. Some tests have been done to assess the sampling density influence on results and to find the right balance between cost and effectiveness. The right sampling grid Grid dimension=chamber diameter Extraction Starting from 900 sampling sites, the total emission estimation seems to be reliable up to a total of 50 measurements points. The most important effect is on flux maps that show drastic change from the real situation

58 MASSA Spin-off – Riduzione dei rischi ambientali A critical revision of the data set is the first step of any kind of elaboration. This preliminary analysis have to be focused to: i.Evaluation of the influence of non detects values; ii.Detection of outlier values iii.Determination of the correct weight for the outlier values when there is a clear origin (e.g. fractures) The presence of outliers can be tested by means of both Box-Whisker plots and other analytical process based on the Central Limit Theorem (Sigh A., 1993; Sigh et al., 1997), depending on the statistical distribution of the data set. Values lower than the instrumental detection limits are usually treated as zero values. How to get global gas emission estimation from punctual measurements ?

59 MASSA Spin-off – Riduzione dei rischi ambientali Isoflux maps Isoflux maps are a fundamental tool to identify anomalous degassing areas and to estimate the flux values where there are not measurements. The question is: how to get reliable maps ? There are a lot of deterministic interpolation methods: i.Nearest neighbor method; ii.Moving average within a neighborhood iii.Inverse distances (IDW) iv.Inverse of distances or squared distances v.Spline vi.………

60 MASSA Spin-off – Riduzione dei rischi ambientali Isoflux map

61 MASSA Spin-off – Riduzione dei rischi ambientali Standard deviation map

62 MASSA Spin-off – Riduzione dei rischi ambientali Isoflux maps: how to choose? Inverse distances Inverse of squared distances  Deterministic approach  The calculation of the weights is only based on the geometric location of the measured data  For a given data configuration, whatever the phenomenon looks like (from regular to erratic), we get the same prediction map  Making a choice needs to add subjective criteria as, « does the map look realistic or not ? »

63 MASSA Spin-off – Riduzione dei rischi ambientali Geostatistics is based on the definition of a regionalized variable, a variable with geographic data location, continuous in the space, with deterministic and random correlation in each point. To investigate these correlations mean to understand the spatial structure of the observed phenomenon. The tool used to get information about spatial correlation and structure is the (semi)variogram. Interpolation data processing with geostatistics methods mean to follow 5 main steps: Data analysis and computation of variogram and variogram cloud; Selecting of the right mathematical model to fit the experimental variogram; Choosing of the proper neighborhood Cross validation Kriging Kriging method (Krige 1951; Matheron, 1962; 1965; 1969; 1970; Clark, 1979; David, 1977; Davis, 1986) allow to extrapolate values where the measures had not been taken. Isoflux maps: geostatistics methods

64 MASSA Spin-off – Riduzione dei rischi ambientali Variogram cloud Data base map Experimental Variogram Kriging e costruzione del semivariogramma Variogram model

65 MASSA Spin-off – Riduzione dei rischi ambientali Come si fa la valutazione globale dei flussi di gas The total flux can be determined with the integral Specific Flux

66 MASSA Spin-off – Riduzione dei rischi ambientali Isotopic gas monitoring Two reasons Identification of biological processes Source identification

67 MASSA Spin-off – Riduzione dei rischi ambientali Area: 10Kmx10Km Grid: 250 m Nx=40 Ny=40 Data input Diffuse pollution from landfill Landfill surface m 2 Modeled compound: CH4 AIR POLLUTION MODELING : CALPUFF

68 MASSA Spin-off – Riduzione dei rischi ambientali hourly concentrations

69 MASSA Spin-off – Riduzione dei rischi ambientali Thank you for your attention… OBRIGADO!


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