Assessment and comparison of the environmental performances of a regional incinerator network

Embed Size (px)

Text of Assessment and comparison of the environmental performances of a regional incinerator network

  • hee

    eP

    sity

    Febine

    1. Introduction

    heavy metals, is a suitable procedure to understand themost direct impacts (Rumbold and Mihalik, 2002), moreintegrated information can be given by the joint applica-

    tion of the monitoring approach and life cycle assessment

    waste management: landlls (Camobreco et al., 1999),end-of-life of specic product categories (Song and Hyun,1999; John and Zordan, 2001; Roth and Eklund, 2003),incineration (Hellweg et al., 2001; Chevalier et al., 2003;Morselli et al., 2005), liquid waste treatment (Hofstetteret al., 2003), municipal policy (Mendes et al., 2004), general

    * Corresponding author. Tel.: +39 051 2093668; fax +39 051 2093863.E-mail address: luciano.morselli@unibo.it (L. Morselli).

    Waste Management 2Incineration is one of the most important activities in anintegrated waste management system, due to the capacityof destroying hazardous waste, reducing mass and volumeof residues and recovering energy content from unrecycla-ble materials having a signicant heat value. However, itsusefulness is sometimes questioned because of its environ-mental impact, particularly on a small scale due to the pol-lutant dispersion in the vicinity (Morselli et al., 2002a,b). Ifa monitoring network close to the plant, designed to assessthe environmental fate of environmental indicators such as

    (LCA) methodology. Indeed, LCA can provide a morecomplete view of environmental impacts, not limited tothe local implications, and at the same time, can suggestto intensify the analytical investigation to those contami-nants that can produce the greatest danger to humanhealth and ecosystem.

    Recently this methodology, which was initially designedfor the environmental impact assessment of products, wasfurther developed for a wide range of applications, partic-ularly for waste management activities and strategic plan-ning. The following are a few applications in the eld ofAbstract

    In Emilia-Romagna region (Northern Italy) the integrated waste treatment system consists of material collection and recycling, incin-eration with energy recovery and landll as nal disposal. In particular, at least one incineration plant is working in almost every prov-ince of the region. In this work, a screening life cycle assessment approach is applied to seven dierent incinerators, to compare thedierent plant technologies and identify the most relevant environmental impacts and processes. The characterization method used inthe life cycle impact assessment step is Eco-indicator 99. The functional unit is 1 ton of waste input.

    As a rst result, it can be noted that while the combustion systems are rather similar, the main variables are ascribable to gas cleaningoptions and eciency in energy recovery, which result in quite dierent environmental performances. Among heavy metals, particularattention must be paid to Cd and As, due to their high toxicity, despite their low quantities. The impact due to dioxin emission is ordersof magnitude lower than other contaminants (e.g., heavy metals). Furthermore, a catalytic system could be useful for a complete removalof organic contaminants and for a more eective abatement of nitrogen oxides. Finally, the environmental impact assessment sorts thevarious plants according to their age, i.e., the most recent plants provide the best environmental performances for the same quantity ofcombusted waste. 2007 Published by Elsevier Ltd.Assessment and comparison of ta regional incin

    Luciano Morselli *, Joseph Luzi, Claudia DFabrizio

    Department of Industrial Chemistry and Materials, Univer

    Accepted 16Available onl0956-053X/$ - see front matter 2007 Published by Elsevier Ltd.doi:10.1016/j.wasman.2007.02.021environmental performances ofrator network

    Robertis, Ivano Vassura, Viviana Carrillo,assarini

    of Bologna, viale Risorgimento 4, I-40136 Bologna, Italy

    ruary 20079 April 2007

    www.elsevier.com/locate/wasman

    7 (2007) S85S91

  • waste management (Finnveden et al., 1995; Barton et al.,1996; Riva et al., 1998; Finnveden, 1999; Clift et al.,2000; Wilson, 2002).

    The aim of this work is the identication of the mostimportant environmental impacts due to the incinerationplants of municipal solid waste (MSW) operating in theEmilia-Romagna region of Italy, and the comparisonbetween the plants in order to highlight the technologicalsolutions most aecting the environmental eciency, forthe same amount of combusted waste.

    2. Materials and methods

    This study has been performed using SimaPro 6.0 LCASoftware (PRe Consultants, NL), implemented, when nec-essary, with Data Base I-LCA of the Italian EnvironmentalProtection Agency (ANPA, 2000). For the environmentalimpact assessment (the LCIA phase), the Eco-indicator99 method was chosen (PRe Consultants, 2001).

    The system boundaries are comprised (as generallyoccurs when a LCA is applied to a waste management sys-tem) from the waste input into the plant to the emission inthe environment (air, water and soil) of ue gas, bottomand y ash and, in this case, sewage sludge (Fig. 1). All

    for the investigation were labelled from A to G, accordingto their age (see Table 1), from the older to the younger.

    All plants are equipped with grate furnaces. They dierconsiderably in age, capacity, energy recovery devices, andpollutant abatement technologies. Table 1 shows an overallview of the most signicant dierences. They all have post-combustion chambers and burn waste in an excess of oxy-gen, at temperatures ranging from 950 C to 1150 C.Waste heat value is almost constant for each plant, rangingfrom about 10,100 to about 10,900 kJ/kg.

    In Table 2, chemical and water consumptions arereported, and in Table 3 the residues coming from the plantare reported. All data are normalised based on 1 t of com-busted waste. Bottom and y ash has to be disposed inlandlls (the latter, previously made inert).

    The entire balance of water and chemical consumptionfor gaseous pollutant abatement like urea, NaHCO3,activated carbon, lime and for water purication usedin an internal plant (not necessary in the cases of D andG plants, which have only a dry abatement system of uegas) like H2SO4, FeCl2, FeCl3, EDTA, NaOH, lime,Na2S, NaClO can thus be calculated.

    Thermal and electric energy recoveries for each plant arereported in Table 4, normalised based on 1 t of combusted

    S86 L. Morselli et al. / Waste Management 27 (2007) S85S91of the operations of waste collection (and their environ-mental impacts) are not included in this study, becausethese considerations would lead beyond the xed aims.

    A questionnaire was prepared and submitted to theplant managers for the collection of primary data, wholled in data with regards to the most relevant input andoutput ows (mass and energy). The seven plants chosenFig. 1. Boundaries of twaste.The normalisation of each mass ow rate for the mass of

    combusted waste is a typical calculation in order to com-pare pollutant emission from dierent plants, obtainingthe so called Emission Factors. These have been calculatedfor all continuously measured parameters (CO2, O2, totalparticulate, CO, TOC, HCl, NO2, SO2, HF) and for peri-he studied system.

  • rela

    anaTable 1Age and working conditions of the investigated incineration plants (Data

    A B C

    Incineration lines(L.)

    L.13 L. 1 L. 12

    L. Morselli et al. / Waste Modically monitored micropollutants (Cd, Tl, Hg, As, Pb,Cr, Co, Cu, Mn, Ni, V, Sb, Sn, PCDD/Fs, PCBs, PAHs.).

    3. Results and discussion

    The reference unit for the stage of impact assessmentwas 1 ton of combusted waste. For the estimation of

    Age (years) 32 (L.1, L.2);31 (L.3)

    29 29

    Combusted waste(t/y)

    155,989 18,620 47,773

    SNCR p

    ESPp

    p

    Fabric lter p

    (activeC + NaHCO3)

    p(active

    C + lime)Scrubber Water,

    NaOH, limeWater Water, NaOH

    Auxiliary fuel (perton of waste)

    Natural gas:4.02 Sm3

    Oil: 3.04 L Natural gas:2.60 Sm3

    pExisting technologies.

    Sm3: Standard cubic meters.SNCR: Selective non catalytic reactor.ESP: Electrostatic lter.

    Table 2Consumption of chemicals and water for each plant (in 2004), normalised for

    A B C

    Urea (kg) 3.31NaHCO3 (kg) 17.8 Active C (kg) 0.48 0.61Lime (kg) 2.59 5.46NaOH (kg) 1.61 2.09Water (m3) 1.47 2.35 2.51Deminer. water (m3) 0.045 0.126

    Table 3Residues from the plants (2004), normalised based on 1 t of combusted waste

    A B C

    Gaseous emissions (Nm3/t of waste) 5.5 103 1.5 104 7Bottom ash (t/t of waste) 0.265 0.303 0Ash from ESP (kg/t of waste) 31.9 1Ash from fabric lter (kg/t of waste) 25.4 6RSP* (kg/t of waste) Dry sewage (kg/t of waste) 3.5 8

    * Residual sodic products, resulting from ue gas cleaning and sent to recyc

    Table 4Thermal and electric energy produced by each incineration plant (2004), norm

    A

    Electric energy produced (minus internal consumption) (MW h/t) 0.183Thermal energy produced (GJ/t) 1.20tes to year 2004)

    D E F G

    L.13 L.13 L.1 L.12

    gement 27 (2007) S85S91 S87avoided impact, the environmental impact due to the sameamount of energy produced considering Italian energy mix,has been calculated.

    In Fig. 2, according to the Eco-indicator 99 method, thedamage assessment is reported, divided into three catego-ries: human health, ecosystem and resources, comparingall plants. Damage categories synthetically describe the

    29 (L.1, L.2); 14(L.3)

    25 (L.1, L.2); 9(L.3)

    12 3

    117,999 99,538 36,128 104,937

    p p p pp p

    p

    p(active

    C + NaHCO3)

    p(active

    C + NaHCO3)

    p(active

    C + lime)

    p(active

    C + NaHCO3) Water Water

    Natural gas:4.07 Sm3

    Natural gas:0.28 Sm3. Oil:0.2 L

    Oil: 0.90 L Natural gas:1.43 Sm3

    1 t of