Life cycle assessment of a pyrolysis/gasification plant for hazardous paint waste

Goal, Scope and Background Life Cycle Assessment (LCA) remains an important tool in Dutch waste management policies. In 2002 the new National Waste Management Plan 2002–2012 (NWMP) became effective. It was supported by some 150 LCA studies for more than 20 different waste streams. The LCA results provided a benchmark level for new waste management technologies. Although not new, operational techniques using combined pyrolysis/gasification are still fairly rare in Europe. The goal of this study is to determine the environmental performance of the only full scale pyrolysis/gasification plant in the Netherlands and to compare it with more conventional techniques such as incineration. The results of the study support the process of obtaining environmental permits. Methods In this study we used an impact assessment method based on the guidelines described by the Centre of Environmental Science (CML) of Leiden University. The functional unit is defined as treatment of 1 ton of collected hazardous waste (paint packaging waste). Similar to the NWMP, not only normalized scores are presented but also 7 aggegated scores. All interventions from the foreground process (land use, emissions, final waste) are derived directly from the site with the exception of emissions to soil which were calculated. Interventions are accounted to each of the different waste streams by physical relations. Data from background processes are taken from the IVAM LCA database 4.0 mostly originating from the Swiss ETH96 database and adapted to the Dutch situation. Allocation was avoided by using system enlargement. The study has been peer reviewed by an external expert. Results and Discussion It was possible to determine an environmental performance for the pyrolysis/ gasification of paint packaging waste. The Life Cycle Inventory was mainly hampered by the uncertainty occurred with estimated air emissions. Here several assumptions had to be made because several waste inputs and two waste treatment installations profit from one flue gas cleaning treatment thus making it difficult to allocate the emission values from the flue gasses. Compared to incineration in a rotary kiln, pyrolysis/gasification of hazardous waste showed better scores for most of the considered impact categories. Only for the impact categories biodiversity and life support the incineration option proved favorable due to a lower land use. Several impact categories had significant influence on the conclusions: acidification, global warming potential, human toxicity and terrestrial ecotoxicity. The first three are related to a better energy efficiency for pyrolysis/gasification leading to less fossil energy consumption. Terrestrial ecotoxicity in this case is related to specific emissions of mercury and chromium (III). A sensitivity analysis has been performed as well. It was found that the environmental performance of the gasification technique is sensitive to the energy efficiency that can be reached as well as the choice for the avoided fossil energy source. In this study a conservative choice for diesel oil was made whereas a choice for heavy or light fuel oil would further improve the environmental profile. Conclusions Gasification of hazardous waste has a better environmental performance compared to the traditional incineration in rotary kilns mainly due to the high energy efficiency. As was determined by sensitivity analysis the differences in environmental performance are significant. Improvement options for a better performance are a decrease of process emissions (especially mercury) and a further improvement of the energy balance by decreasing the electricity consumption for shredders and oxygen consumption or making more use of green electricity. Recommendations and Perspectives Although the life cycle inventory was sufficiently complete, still some assumptions had to be made in order to establish sound mass balances on the level of individual components and substances. The data on input of waste and output of emissions and final waste were not compatible. It was recommended that companies put more emphasis on data storage accounted to particular waste streams. This is even more relevant since more companies in the future are expected to include life cycle impacts in their environmental performance.     

Life cycle environmental and economic assessment of lead refining in China

Purpose

Lead is one of the most commonly used metals in the past millennium because of its various properties. Moreover, lead is easy to extract and handle. However, the lead industry often encounters strong public opposition because of lead poisoning. This study analyzes the economic and environmental impacts of lead in China, which is the world’s largest producer and consumer of lead.

Methods

Life cycle assessment coupled with life cycle costing was conducted to estimate the environmental and economic impacts of primary and secondary lead refining in China. The internal cost (i.e., raw materials and energy consumption, labor, tax, interest, transport, infrastructure, depreciation, and maintenance) and external market price (i.e., carbon, ammonia, arsenic, COD, lead, mercury, nitrogen oxides, particulates, sulfur dioxide, and land eco-remediation) are considered.

Results and discussion

The overall environmental burden was mainly generated from the human toxicity and marine ecotoxicity categories for both primary and secondary lead refining scenarios because of the direct lead emission in the air and water. For the primary lead refining, the effect on metal depletion represented an additional dominant contribution to the overall environmental burden. The overall economic impact was mainly attributed to lead ore or waste lead, tax, labor fee, and emission cost of ammonia and chromium. In 2013, approximately 5.61 Mt CO₂ eq, 5.81 Mt 1,4-DB eq, 6.59 kt 1,4-DB eq, 7.86 kt 1,4-DB eq, 1.82 Mt·kg Fe eq, 2.37 Mt·kg oil eq, and $9.9 billion were recorded from the lead industry in China in the climate change, human toxicity, freshwater ecotoxicity, marine ecotoxicity, metal depletion, fossil depletion, and economic impact categories, respectively. Additionally, approximately 0.4 kt lead, 18.4 kt sulfur dioxide, 15.6 kt nitrogen oxide, and 6.4 kt particulate emissions in the same year were released from the lead industry in China.

Conclusions

Approximately 57 to 96 % environmental benefits through waste lead recycling in all key categories were observed, whereas its economic benefit was low. The key factors that contribute in reducing the overall environmental and economic impacts include reducing direct lead emissions in air and water, increasing the national recycling rate of lead, replacing coal with clean energy sources for electricity production, improving heavy metal-removing technologies from mining wastewater, and optimizing the efficiency of electricity, lead ore, coal, oxygen, natural gas, and sodium carbonate consumption.

     

Application of life cycle assessment to landfilling

A case study of a life-cycle assessment (LCA) is performed concerning the treatment of household solid wastes in a landfill. The stages considered in this LCA study are: goal and scope definition, inventory analysis and impact assessment. The data of the inventory include the consumption of raw materials and energy through the transport of wastes and the management of landfill, and the corresponding emissions to the environment. Abiotic resource depletion, global warming, acidification, eutrophication and human toxicological impacts have been considered as impact categories for the impact assessment phase of the LCA. A comparison of the environmental impact of the landfilling with and without energy recovery is carried out. Members of the Spanish Association for LCA Development (APRODACV)     

Life cycle assessment of municipal waste water systems

Life Cycle Assessment was applied to municipal planning in a study of waste water systems in Bergsjön, a Göteborg suburb, and Hamburgsund, a coastal village. Existing waste water treatment consists of mechanical, biological and chemical treatment. The heat in the waste water from Bergsjön is recovered for the district heating system. One alternative studied encompassed pretreatment, anaerobic digestion or drying of the solid fraction and treatment of the liquid fraction in sand filter beds. In another alternative, urine, faeces and grey water would separately be conducted out of the buildings. The urine would be used as fertilizer, whereas faeces would be digested or dried, before used in agriculture. The grey water would be treated in filter beds. Changes in the waste water system would affect surrounding technical systems (drinking water production, district heating and fertilizer production). This was approached through system enlargement. For Hamburgsund, both alternatives showed lower environmental impact than the existing system, and the urine separation system the lowest. Bergsjön results were more difficult to interpret. Energy consumption was lowest for the existing system, whereas air emissions were lower for the alternatives. Water emissions increased for some parameters and decreased for others. Phosphorous recovery was high for all three alternatives, whereas there was virtually no nitrogen recovery until urine separation was introduced.     

Life cycle energy and environmental benefits of a US industrial symbiosis

Purpose

The industrial ecosystem identified in and around the Campbell Industrial Park in Honolulu County, Hawai’i involves 11 facilities exchanging water, materials, and energy across an industrial cluster. This paper highlights the advantages of this arrangement using life cycle assessment to determine the energy and environmental costs and benefits of the existing pattern of exchanges.

Methods

A consequential approach was used to evaluate each material substitution for four environmental impact categories: primary energy use, greenhouse gas (GHG) emissions, acidification, and eutrophication. Each material exchange included avoided production and reduced use of virgin materials, any necessary pre-processing or transportation of local by-products, and avoided treatment or disposal of these by-products.

Results and discussion

All exchanges exhibited positive net savings across all environmental impact categories, with the exceptions of waste oil and tire-derived fuel burned as substitutes for coal. The greatest savings occur as a result of sharing steam between a combined cycle fuel oil-fired cogeneration plant and a nearby refinery. In total, the environmental savings realized by this industrial cluster are significant, equivalent to 25 % of the state’s policy goal for reducing the industrial component of GHG emissions over the next decade. The role of policy in supporting material and energy exchanges is also discussed as the central cluster of two power plants and two refineries share steam and water in part under regulatory requirements.

Conclusions

The results show environmental benefits of the sharing of by-product resources accrued on a life cycle basis, while for the local context, the reduction of imported fuels and materials helps to reduce the external dependency of Oahu’s remote island economy. The environmental benefits of materials exchanges are often ignored in energy policy, though, as in this case, they can represent considerable savings.     

Life cycle assessment (LCA) of industrial milk production

A Life Cycle Assessment (LCA) was carried out for milk production extending from the origin of the inputs to the agricultural step to the consumer phase and the waste management of the packaging. Three Norwegian dairies of different sizes and degree of automation were studied. The main objectives were to find any hot spots in the life cycle of milk, to determine the significance of the dairy size and degree of automation, and to study the influence of transport. The agriculture was found to be the main hot spot for almost all the environmental themes studied, although the dairy processing, packaging, consumer phase and waste management were also of importance. The consumer phase was the main contributor to photo-oxidant formation and important regarding eutrophication. The small dairy was found to have a greater environmental impact than the middle-sized and the largest dairies. The transport did not have any major influence.     

Life cycle assessment of waste strategies for used lubricating oil

Purpose

The study aimed to evaluate the environmental impacts of used lubricating oil (ULO) recovery in the largest oil consumer country in Africa, Egypt. The main questions were: What are the impacts of the different waste management strategies for the recovery of used lubricating oil and which waste management strategy is more eco-friendly?

Methods

Life cycle assessment (LCA) was employed to model the environmental impacts of the two waste management approaches for used lubricating oil recovery in Egypt: recycling by re-firing and recovery by co-firing. The model was applied to assess the impacts of one of the largest ULO recovery units in the Middle East and North Africa (MENA) region and the only operating unit in Egypt. The following impact categories were included: global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), carcinogens potential (CP), ecotoxicity potential (ETP), respiratory inorganic formation potential (RIFP), respiratory organic formation potential (ROFP), radiation potential (RP), ozone layer depletion (OLD), mineral depletion (MD), land use (LU) and fossil fuel depletion (FFD).

Results and discussion

Results indicated that recycling by re-refining strategy is more environment-friendly. De-asphalting, de-aromatization and de-waxing processes are the main processes that affect the environmental impacts of lubricating oil production in both strategies, due to the use of hazard materials and toxic solvents in these processes. Fuel gas and fuel oil used as a fuel in the refinery and power units are the main contributors affecting the environmental impacts in case of recycling by re-refining strategy. The highest impacts were detected on FFD, followed by RIFP, GWP, AP, EP, ETP and CP in both strategies; no impacts were detected on RP, OLD and MD.

Conclusions

It can be concluded that recycling by re-refining of ULO is the more eco-friendly approach. This strategy is more energy conservative, saves a diminishing fossil fuel resource and reduces burdens on the environment. ULO containing high percentages of additive remnants such as viscosity index improvers and pour point depressants which represents a valuable resource and its proper management should be given the most attention.

     

Life cycle assessment of a waste lubricant oil management system

Purpose

This paper compares 16 waste lubricant oil (WLO) systems (15 management alternatives and a system in use in Portugal) using a life cycle assessment (LCA). The alternatives tested use various mild processing techniques and recovery options: recycling during expanded clay production, recycling and electric energy production, re-refining, energy recovery during cement production, and energy recovery during expanded clay production.

Methods

The proposed 15 alternatives and the actual present day situation were analyzed using LCA software UMBERTO 5.5, applied to eight environmental impact categories. The LCA included an expansion system to accommodate co-products.

Results

The results show that mild processing with low liquid gas fuel consumption and re-refining is the best option to manage WLO with regard to abiotic depletion, eutrophication, global warming, and human toxicity environmental impacts. A further environmental option is to treat the WLO using the same mild processing technique, but then send it to expanded clay recycling to be used as a fuel in expanded clay production, as this is the best option regarding freshwater sedimental ecotoxicity, freshwater aquatic ecotoxicity, and acidification.

Conclusions

It is recommended that there is a shift away from recycling and electric energy production. Although sensitivity analysis shows re-refining and energy recovery in expanded clay production are sensitive to unit location and substituted products emission factors, the LCA analysis as a whole shows that both options are good recovery options; re-refining is the preferable option because it is closer to the New Waste Framework Directive waste hierarchy principle.     

Life cycle assessment of alternatives for waste-solvent valorization: batch and continuous distillation vs incineration

Purpose

The goal and scope of this research is focused on the application of life cycle assessment (LCA) to evaluate two alternatives (batch and continuous distillation and incineration with energy recovery) for the treatment of four waste-solvent mixtures typically produced in the chemical industry: acetonitrile–toluene, acetonitrile–toluene–tetrahydrofuran (THF), ethyl acetate–water and methanol–THF, with several compositions in order to determine the most appropriate technology depending on the characteristics of the mixture.

Materials and methods

Ecosolvent® v.1.0.1 software is used to perform the LCA, considering two scenarios and the following methods of impact assessment: Eco-indicator 99, cumulative energy demand, method of ecological scarcity (UBP’97), global warming potential and CO₂ balances.

Results and discussion

Results show that distillation gives more environmental credits for the recovery of the most concentrated compound in acetonitrile–toluene mixtures. However, when THF is present in the waste solvent even in small quantities, it has to be recovered due to the high impact associated to its manufacture. Regarding the mixture ethyl acetate–water, distillation takes advantage at concentrations of ethyl acetate higher than 50 wt%, and for the mixture methanol–THF, recovery of methanol is not advantageous from an environmental point of view, but the recovery of THF is clearly necessary to decrease the total impact.

Conclusions

From this study, it can be concluded that those compounds that yield a great environmental burden during the production step should be always recovered in order to minimize the total impact, even if they represent the minor concentration in the mixture. In case that similar impact is produced during the solvent production, the major compound in the mixture should be the target for recovery.

     

Life cycle environmental and economic assessment of coal seam gas-based electricity generation

The International Journal of Life Cycle Assessment - A large portion of coal seam gas is directly wasted and emitted to the environment, especially China, which is the world’s largest global...     

Life cycle assessment comparison among different reuse intensities for industrial wooden containers

Goal, scope and background  The industrial packages sector has great importance for the transport sector in Europe. These containers, mainly wooden pallets and spools, are subject to European legislation, which promotes their reuse and recycling. This study uses life cycle assessment (LCA) to assess the environmental impact of the current management system in this sector and the benefits and drawbacks of different reuse intensities as a waste prevention strategy as opposed to the recycling option. Materials and methods  In this paper, four case studies located in Spain and representative of the wooden package sector in Europe are analysed: high reuse pallet, low reuse pallet, low reuse spool and null reuse spool. For the LCA study cases, the functional unit is that required to satisfy the transport necessity of 1,000 t by road. The impact and energy consumption assessment methods used are CML 2 Baseline 2000 and Cumulative Energy Demand. Data are mostly provided by the leading enterprises and organisations in this sector. Results  The paper provides, as a first result, a comprehensive inventory of the systems under study. Secondly, our assessment shows that the systems with higher reuse intensity show a reduction in energy and wood consumption and all the environmental impact categories except for the global warming potential from 34.0% to 81.0% in the pallet study cases and from 50.4% to 72.8% in the spool ones. This reduction is at the expense of the maintenance stage, which on the contrary increases its impact, although it is still relatively small—less than 7% in all the impact categories and flow indicators of the study cases. The highest impact stages are transport, raw material extraction and the process chain. The final disposal and maintenance stages are the lowest impact, contributing at most to less than 30% of the impact in the pallet study cases and 10% in the spool cases. Discussion  Wood consumption (WC), directly related to the number of containers needed to satisfy the functional unit, is the main factor in determining the impact of the stages, especially in the raw materials extraction and process chain stages, assuming that these are undertaken with the same technologies in all the case studies. Other variables, such as the management system, the maintenance index and the final disposal scenario, affect the impact of the remaining stages: transport, maintenance and final disposal. The global warming potential results obtained demonstrate the environmental benefits of using containers made of a renewable resource such as wood instead of using other materials, but these results are not expected to prioritise the lower reuse systems because of their better performance in this category. Conclusions  Reuse, a strategy capable of reducing the environmental impacts of the wooden container systems, is preferable to recycling, while the package maintenance tasks are still feasible. Therefore, reuse, combined with recycling as final disposal, should be encouraged to reduce the demand for natural resources and the waste generated. Recommendations  Based on these results, attention should be paid to the maintenance stage, which, being the lowest-impact one, could substantially reduce the impact of the remaining stages.     

Life cycle assessment of passively aerated composting in gas-permeable bags of olive mill waste

The International Journal of Life Cycle Assessment - In Italy, composting olive mill waste has become a common practice, since it mitigates the environmental problems associated with spreading the...     

Comparative life cycle assessments of incineration and non-incineration treatments for medical waste

Background, aim, and scope  Management of the medical waste produced in hospitals or health care facilities has raised concerns relating to public health, occupational safety, and the environment. Life cycle assessment (LCA) is a decision-supporting tool in waste management practice; but relatively little research has been done on the evaluation of medical waste treatment from a life cycle perspective. Our study compares the environmental performances of two dominant technologies, hazardous waste incineration (HWI) as a type of incineration technology and steam autoclave sterilization with sanitary landfill (AL) as a type of non-incineration technology, for specific medical waste of average composition. The results of this study could support the medical waste hierarchy. Materials and methods  This study implemented the ISO 14040 standard. Data on steam autoclave sterilization were obtained from an on-site operations report, while inventory models were used for HWI, sanitary landfill, and residues landfill. Background data were from the ecoinvent database. The comparative LCA was carried out for five alternatives: HWI with energy recovery efficiencies of 0%, 15%, and 30% and AL with energy recovery efficiencies of 0% and 10%. Results  The assumptions on the time frame for landfill markedly affect the impact category scores; however, the orders of preference for both time frames are almost the same. HWI with 30% energy recovery efficiency has the lowest environmental impacts for all impact categories, except freshwater ecotoxicity. Incineration and sanitary landfill processes dominate global warming, freshwater aquatic ecotoxicity, and eutrophication of incineration and non-incineration alternatives, respectively. Dioxin emissions contribute about 10% to human toxicity in HWI without energy recovery alternatives, and a perturbation analysis yielded identical results. As regards eutrophication, non-incineration treatments have an approximately sevenfold higher impact than incineration treatments. Discussion  The differences between short-term and long-term time frame assumptions mainly are decided by heavy metals dissolved in the future leachate. The high heat value of medical waste due to high contents of biomass, plastic, and rubber materials and a lower content of ash, results in a preference for incineration treatments. The large eutrophication difference between incineration and non-incineration treatments is caused by different N element transformations. Dioxin emission from HWI is not the most relevant to human toxicity; however, large uncertainties could exist. Conclusions  From a life cycle perspective, the conventional waste hierarchy, implying incineration with energy recovery is better than landfill, also applies to the case of medical waste. The sanitary landfill process is the key issue in non-incineration treatments, and HWI and the subsequent residues landfill processes are key issues in incineration treatments. Recommendations and perspectives  Integrating the medical waste hierarchy and constructing a medical waste framework require broader technologies to be investigated further, based on a life cycle approach. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Life cycle assessment standards

The newly emerging LCA standards provide an opportunity to review and improve upon the current LCA methodology. As more industrial practitioners enter the arena, the opportunity arises to not only demand environmental improvement from industrial service and product providers but also to fill LCA data gaps. A framework is suggested for improvement in the current LCA framework that focuses on the business relationships of the industrial practitioner. The framework seeks to promote environmental improvement from industrial sectors through the identification of state-of-the-art technologies used throughout a life cycle. Basing LCAs on the best performers in an industry will create a market for a high level of environmental performance, disperse the responsibility of inventory data gathering, and improve upon the advancements already anticipated through the widespread application of LCA.