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On leachate emissions from municipal solid waste

van Praagh, Martijn LU (2007)
Abstract (Swedish)
Popular Abstract in Swedish

Mängden och kvaliten på avfall förändras när intresset för resurserna i avfallet ökar. Ett omhändertagande av avfall med sortering, återvinning, förbehandling och utnutjande av energi producerar nytt avfall. En del hamnar på deponin. En möjlig följd är att det organiska materialet som deponeras minskar. En annan är att avfallet blir torrare. Framförallt inom EU finns det krav på att innesluta avfallet i en deponi och hålla det så torrt som möjligt. Potentiella och verkliga emissioner från dessa deponier kan antas skiljer sig från gamla hushållstippar. Syftet med detta arbete är att belysa möjliga förändringar som ett förändrat omhändertagande av avfall medför för lakvattenutsläpp från deponier.... (More)
Popular Abstract in Swedish

Mängden och kvaliten på avfall förändras när intresset för resurserna i avfallet ökar. Ett omhändertagande av avfall med sortering, återvinning, förbehandling och utnutjande av energi producerar nytt avfall. En del hamnar på deponin. En möjlig följd är att det organiska materialet som deponeras minskar. En annan är att avfallet blir torrare. Framförallt inom EU finns det krav på att innesluta avfallet i en deponi och hålla det så torrt som möjligt. Potentiella och verkliga emissioner från dessa deponier kan antas skiljer sig från gamla hushållstippar. Syftet med detta arbete är att belysa möjliga förändringar som ett förändrat omhändertagande av avfall medför för lakvattenutsläpp från deponier. Dessutom är syftet att utveckla metoder som kan användas för att både beskriva emissioner och emissionspotentialer.



En kombination av olika experiment i laboratorium och av analytiska verktyg har använts inom detta arbete. Både avfallets totalhalter av grundämnen och karakterisiering av lakvattensammansättningen har kombinerats med tester som visar avfallets stabilitet mot nedbrytning. För att finna och statistiskt säkerställa samband mellan parametrarna har resultaten använts i multivariata analyser.



Organiskt material spelar en betyndande roll för emissioner från förbehandlat avfall. Å ena sidan can metaller bindas i en större utsträckning till fast organiskt material. Å andra sidan kan metaller bli mobiliserade med organiskt material i lakvattnet. Totalhalten organiskt material, mätt som totalhalt organiskt kol, är ett gränsvärde i till exempel Sveriga för att få lov och lägga avfall på deponien. Totalhalt organiskt kol visar sig vara en parameter som är mindra lämpligt att återge avfallets stabilitet än nedbrytningstester eller tester på det organiska materialets egenskaper.



Kolonntester används som standard för att utvärdera lakningsbenägenhet av ämnen i avfall. Kontakten mellan avfallet och vattnet förstärks och utlakningen accellereras i laboratoriet. Testerna tilllåter inte att kontrollera kontakten mellan det fasta materialet och vattnet, och möjliga reaktioner mellan dessa kan inte upptäckas. Heterogeniteten i provet kan inte kontrolleras och en uppskattning av hur avfallet skulle lakar på deponin utifrån standardtester blir mycket osäker. Genom att införa en mätteknik, så kallat ?time domain reflectometry?, i kolonntester kan vattnets rörelser och kontakten mellan avfallet och vattnet kontrolleras. Experiment med denna metod har visat att porvattnets hastighet genom avfallet har större betydelse för lakvattenkoncentrationer än att introducera en potentiellt mobiliserade förorening, i detta fall organiskt material. Dessutom visar sig att just reaktionen av kalkrika avfall som aska från stofftavskiljningen på en avfallsförbränningsanläggning med vatten behöver utredas mera med hansyn till lakvattenkoncentrationer i det långa loppet från dessa avfallsslag.



En kombination av kolonntester, kemisk jämviktsmodellering, ?time domain reflectometry? och en statistisk utvärdering med multivariata modeller har visat sig kunna tillföra information om hur avfallets utlakningspotential förändras när dess omhändertagande förändras. Därigenom kan specifika deponeringsscenarier bli möjliga. I fallet av askan från stofftavskjilkningen skulle en forcerat utlakning till ett förhållande vatten till avfall av 2 har uppnåtts med anslutande tät förvaring medföra minst risk av utlakning för kommande generationer.



Dessutom möjliggör den ökande kunskapen om avfallet att ta hansyn till lakvattenomhändertagande när miljökonsekvenser av olika avfallsstrategier utreds. Hur allvarliga konsekvenserna för människan och miljön blir beror inte minst på recipienten lika mycket som på föroreningskällan. (Less)
Abstract
When attention is drawn to the recovery of resources within waste, the amount and types of waste disposed of at landfills change. A waste management system based on separate kerbside collection, sorting, recycling, and pretreatment with material and/or energy recovery produces new residues, which finally end up at landfills. This is the case in, for example, the US and the EU. As a possible result, the amount of organic material being deposited at landfills is reduced. In the EU, the remains from pretreatment are landfilled in containments, which have to be kept dry after closure, and the contact between the waste and its surroundings is restricted. The potential and actual emissions from landfills might be altered compared to the renowned... (More)
When attention is drawn to the recovery of resources within waste, the amount and types of waste disposed of at landfills change. A waste management system based on separate kerbside collection, sorting, recycling, and pretreatment with material and/or energy recovery produces new residues, which finally end up at landfills. This is the case in, for example, the US and the EU. As a possible result, the amount of organic material being deposited at landfills is reduced. In the EU, the remains from pretreatment are landfilled in containments, which have to be kept dry after closure, and the contact between the waste and its surroundings is restricted. The potential and actual emissions from landfills might be altered compared to the renowned waste management system unambiguously built on discarding untreated waste. The scope of this work is to elucidate possible resulting changes in emission potentials from landfilled municipal solid granular waste with their leachates, and to develop methods describing both emission potentials and actual emissions more accurately.



A combination of different lab-scale experimental setups and analytical approaches are utilized in this work. The characterization of emission potentials is undertaken by analyzing total contents, the waste material's dielectric permittivity and the mineral phases of fresh and leached wastes. This is accompanied by testing their susceptibility for degradation with the aid of respiration activity and gas formation potential tests. Actual emissions are assessed by measuring ions of soluble salts, metals, and potentially oxygen depleting substances in the leachate emitted from granular waste materials leached with water. In order to verify the interconnection of parameters for determining emissions and those determining emission potentials, multivariate statistical analyses are used.



Organic material plays an important role for leachate emissions from pretreated wastes. On the one hand, heavy metals might be bound to solid humic material to a higher extent after pretreatment. On the other hand, they might be mobilized with organic matter transported in the leachate even after pretreatment. Total organic carbon content of waste, a limit value employed in Sweden for diverting waste from landfills, proves to be less accurate in defining reduced emission potential by pretreatment than degradation tests, or analyzing the properties of organic carbon left in the solid.



In standard laboratory percolation tests, which are used to describe emissions caused by moving water, the contact between solution and solute, measured as liquid to solid ratio, is artificially enhanced and accelerated. This modification is employed in order to resemble a worst case scenario within a limited time frame for the experiments. Up till now, neither the intensity of this contact nor the pore water velocity are tested nor controlled. The reaction of water with the solid waste and pore heterogeneities adds to the unreliability of translating liquid to solid ratios from the laboratory to field situations. The former issues can have a large impact on emissions and remaining emission potentials of wastes. By introducing an electromagnetic measuring technique, called Time Domain Reflectometry (TDR), into a column percolation test, monitoring the movement of water and solutes through wastes can be achieved. The effect of mean travel time on liquid emissions outweighs the importance of introducing a potentially mobilizing leaching agent, in this case dissolved organic carbon. Inorganic material and the supersaturation of calcite are identified as issues which deserve more attention in future work for assessing emissions and emission potentials regarding heavy metals from pretreated, granular wastes.



Characterization of granular wastes by means of percolation tests in combination with chemical speciation modelling, monitoring of solution and solute, and evaluating the data with advanced statistical tools can enhance information on how potential emissions from waste change when alternative management options are chosen. Specific landfill scenarios with reduced liquid emissions and reduced emission potential can be developed. In the case of an air pollution control residue from waste incineration, forced leaching until a liquid to solid ratio of 2 with subsequent tight capping is suggested as a landfill scenario with minimum remaining emission potential in the long term.



The performance of mitigation measures such as leachate treatment is ideally taken into regard, when environmental impacts of waste management options are elucidated. The severity of environmental impacts of pretreated wastes depends also on their final use and location, and the recipient's susceptibility for its emissions, as shown for a recovered refuse material in this work. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Professor Lagerkvist, Anders, Division of Waste Science and Technology, Luleå University of Technology
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Hydrogeology, Miljöstudier, Environmental studies, Environmental Impact, heavy metals, Organic carbon, teknisk geologi, Hydrogeologi, geographical and geological engineering, teknisk geografi
pages
240 pages
publisher
Water Resources Engineering, Lund University
defense location
Lund Tekniska Högskola, Sölvegatan 26, Ingvar Kamprad Designcentrum, Lund, stora hörsalen (DC:Shö)
defense date
2007-12-07 09:15
ISSN
1101-9824
ISBN
978-91-628-7344-8
language
English
LU publication?
yes
id
44622da5-16dc-4189-a3bc-019554c1e3bc (old id 599329)
date added to LUP
2007-11-22 11:56:03
date last changed
2016-09-19 08:44:52
@phdthesis{44622da5-16dc-4189-a3bc-019554c1e3bc,
  abstract     = {When attention is drawn to the recovery of resources within waste, the amount and types of waste disposed of at landfills change. A waste management system based on separate kerbside collection, sorting, recycling, and pretreatment with material and/or energy recovery produces new residues, which finally end up at landfills. This is the case in, for example, the US and the EU. As a possible result, the amount of organic material being deposited at landfills is reduced. In the EU, the remains from pretreatment are landfilled in containments, which have to be kept dry after closure, and the contact between the waste and its surroundings is restricted. The potential and actual emissions from landfills might be altered compared to the renowned waste management system unambiguously built on discarding untreated waste. The scope of this work is to elucidate possible resulting changes in emission potentials from landfilled municipal solid granular waste with their leachates, and to develop methods describing both emission potentials and actual emissions more accurately.<br/><br>
<br/><br>
A combination of different lab-scale experimental setups and analytical approaches are utilized in this work. The characterization of emission potentials is undertaken by analyzing total contents, the waste material's dielectric permittivity and the mineral phases of fresh and leached wastes. This is accompanied by testing their susceptibility for degradation with the aid of respiration activity and gas formation potential tests. Actual emissions are assessed by measuring ions of soluble salts, metals, and potentially oxygen depleting substances in the leachate emitted from granular waste materials leached with water. In order to verify the interconnection of parameters for determining emissions and those determining emission potentials, multivariate statistical analyses are used.<br/><br>
<br/><br>
Organic material plays an important role for leachate emissions from pretreated wastes. On the one hand, heavy metals might be bound to solid humic material to a higher extent after pretreatment. On the other hand, they might be mobilized with organic matter transported in the leachate even after pretreatment. Total organic carbon content of waste, a limit value employed in Sweden for diverting waste from landfills, proves to be less accurate in defining reduced emission potential by pretreatment than degradation tests, or analyzing the properties of organic carbon left in the solid.<br/><br>
<br/><br>
In standard laboratory percolation tests, which are used to describe emissions caused by moving water, the contact between solution and solute, measured as liquid to solid ratio, is artificially enhanced and accelerated. This modification is employed in order to resemble a worst case scenario within a limited time frame for the experiments. Up till now, neither the intensity of this contact nor the pore water velocity are tested nor controlled. The reaction of water with the solid waste and pore heterogeneities adds to the unreliability of translating liquid to solid ratios from the laboratory to field situations. The former issues can have a large impact on emissions and remaining emission potentials of wastes. By introducing an electromagnetic measuring technique, called Time Domain Reflectometry (TDR), into a column percolation test, monitoring the movement of water and solutes through wastes can be achieved. The effect of mean travel time on liquid emissions outweighs the importance of introducing a potentially mobilizing leaching agent, in this case dissolved organic carbon. Inorganic material and the supersaturation of calcite are identified as issues which deserve more attention in future work for assessing emissions and emission potentials regarding heavy metals from pretreated, granular wastes.<br/><br>
<br/><br>
Characterization of granular wastes by means of percolation tests in combination with chemical speciation modelling, monitoring of solution and solute, and evaluating the data with advanced statistical tools can enhance information on how potential emissions from waste change when alternative management options are chosen. Specific landfill scenarios with reduced liquid emissions and reduced emission potential can be developed. In the case of an air pollution control residue from waste incineration, forced leaching until a liquid to solid ratio of 2 with subsequent tight capping is suggested as a landfill scenario with minimum remaining emission potential in the long term.<br/><br>
<br/><br>
The performance of mitigation measures such as leachate treatment is ideally taken into regard, when environmental impacts of waste management options are elucidated. The severity of environmental impacts of pretreated wastes depends also on their final use and location, and the recipient's susceptibility for its emissions, as shown for a recovered refuse material in this work.},
  author       = {van Praagh, Martijn},
  isbn         = {978-91-628-7344-8},
  issn         = {1101-9824},
  keyword      = {Hydrogeology,Miljöstudier,Environmental studies,Environmental Impact,heavy metals,Organic carbon,teknisk geologi,Hydrogeologi,geographical and geological engineering,teknisk geografi},
  language     = {eng},
  pages        = {240},
  publisher    = {Water Resources Engineering, Lund University},
  school       = {Lund University},
  title        = {On leachate emissions from municipal solid waste},
  year         = {2007},
}