Warit, J. - \ 2006
Wageningen University. Promotor(en): L. Hordijk, co-promotor(en): Carolien Kroeze; W. Soontaranun. - [S.l.] : S.n. - ISBN 9789085045106 - 203
pulp- en papierwarenindustrie - pulpfabrieksafvalwater - verzuring - eutrofiëring - industrieel afval - papierfabrieksslib - eucalyptus - thailand - pulp and paper industry - pulp mill effluent - acidification - eutrophication - industrial wastes - paper mill sludge - eucalyptus - thailand
The pulp industry inThailand
is of economic and social importance because of its production value, the revenues from export and the employment in this sector. The eucalyptus-based Kraft pulp industry plays an important role due to its large share in pulp production inThailand
. The demand for Kraft pulp has been increasing as a result of the growth in the manufacturing sector, increasing living standards and new export markets. However, this industry also contributes to several environmental problems, which need to be addressed with an integrated study.
The overall objective of this thesis is to analyse the environmental pressure of the eucalyptus-based Kraft pulp industry inThailand
, and to identify options to reduce these pressures and evaluate their cost-effectiveness. Possible future trends (2000-2020) in the potential environmental impact of this industry, taking into account the technical and economical implications of combinations of environmental reduction options are also analyzed. The study focuses on the overall environmental impact as well as on six specific environmental problems: global warming, acidification, eutrophication, smog, human toxicity and the production of solid waste. The environmental systems analysis (ESA) is used as a main tool in this thesis, to answer three research questions.
Current environmental pressure of eucalyptus-based Kraft pulp industry inThailand
The first research question is to determinethe current environmental pressure of eucalyptus-based Kraft pulp industry inThailand. To this end,the first and second step of the environmental systems analysis were performed. These include problem definition and system definition. A clear definition of the system is given by defining the system inputs, outputs and internal relations. The analysis reveals which inputs, outputs and processes have to be taken into account and which can be omitted. We distinguish between two subsystems within the Kraft pulp industry: eucalyptus forestry and Kraft pulp production. Environmental indicators and a partial life cycle analysis are the tools used for this analysis.
The results indicate that the environmental pressure of the Kraft pulp production exceeds that of eucalyptus forestry.In terms of activities causing environmental problems, the chemical recovery unit was found to be the most important source of global warming and acidification, because it is responsible for more than 50% of the emissions of greenhouse gases and acidifying compounds. Biomass combustion contributes by about 80% to the emissions of tropospheric ozone precursors and human toxicity substances.Almost three quarters of the eutrophying compounds are from wastewater treatment.
In an analysis of options to reduce the environmental pressure of the eucalyptus-based Kraft pulp inThailand
not all emissions need to be taken into account. We identified the emissions that are responsible for at least 85% of the environmental pressure for each environmental theme. These emissions are: CH 4 , N 2 O, NO x , CO, VOC and particulates from biomass combustion, CO 2 and SO 2 from bunker oil used in lime combustion, SO 2 , NO x and VOC from lime combustion, AOX, COD and TRS from pulp production, P from wastewater treatment, and N 2 O and PO 43- from fertilizer use in eucalyptus plantation.
Modeling options to reduce the environmental pressure
The second research question is toidentify options to reduce the environmental pressure caused by the Kraft pulp industry inThailandand to analyzetheir technical reduction potentials and associated costs. To answer this question, the third and fourth steps of environmental systems analysis werecarried out. These include system synthesis (model building) and system analysis (model exploration). An integrated environmental assessment model was built, combining partial life cycle analysis, multi-criteria analysis (MCA) and cost effectiveness analysis.
We developed a model to quantify emissions from the Kraft pulp industry inThailand
and their potential environmental impacts. The model includes those sources and emissions that importantly contribute the potential environmental impact, as identified in the first phase of this study. The potential environmental impact of the emissions was calculated from the total amount emitted per time unit (year) and classification factors of the compounds reflecting their relative importance for specific environmental problems. With respect to the reduction options, the model can be used to evaluate the effect of reduction options on the environmental impact and their associated costs. The model covers options for reducing the environmental impact and takes into account the side effect of reduction options on environmental problems. Thirty six reduction options are identified and categorized into 14 independent groups. The reduction options can affect the activity levels and/or emission factors. Reduction potentials are determined with reference to the situation in which none of the options are applied (reference situation). In addition, the model is capable of evaluating the 'overall' environmental impact using of multi-criteria analysis (MCA), in which an overall evaluation is performed on the basis of different criteria. The 'Analytical Hierarchy Process (AHP)', which is an MCA tool that enables the user to establish weights for selected criteria by means of a series of pair wise comparisons, was used to generate valuation factors for each environmental problem.
The model was explored in a number of ways. First, the results of the model were compared with Thailand-based studies, and it
was found that the model is adequate for analyzing the environmental impact of the Kraft pulp industry inThailand
. Next, the reference case, in which we assume that no options to reduce the environmental impact of Kraft pulp industry are applied, was analyzed. It was found that acidification and eutrophication are the largest environmental problems caused by the Kraft pulp industry inThailand
, contributing by about one-third each to the overall environmental impact. Lime kilns, recovery boilers and pulp bleaching units are the most important sub-units contributing to the overall environmental impact. Finally, the reduction options were analyzed with respect to their effectiveness and cost effectiveness in reducing environmental problems. We found that the most effective options are associated with reducing the emissions of eutrophying and acidifying compounds. These options include options in group wastewater treatment, wastewater minimization, alternative digesting techniques, alternative bleaching techniques, sulfur dioxide control
and odor control
. The most cost-effective options are typically associated with structural changes, such as improving the pulp washing, increasing the dry solid content of black liquor
and spillage control
, which are more cost-effective than typical end-of-pipe technologies such as activated sludge
.Some options were found to be paying options, which means that the annual saving from reducing activity levels and/or emissions is larger than the annual costs. These options include applying optimum doses of fertilizer, extended delignification, enzyme delignification, improve pulp washing, solar heating and O 2 enrichment kilns .
The results of the analysis of the reference case may help decision makers in prioritizing environmental management, while the analyses of the effectiveness and the cost-effectiveness of individual reduction options may help in choosing reduction options that are in line with their preferred environmental strategies. Different environmental strategies will lead to different combinations of options. The model can be used to analyze the environmental consequences and the associated costs of such combinations. As such the model is highly relevant for decision makers.
The last research question is to investigatepossible future trendsin the environmental pressure caused by the eucalyptus-based Kraft pulp industry inThailand.Possible changes in the environmental performance of the eucalyptus-based Kraft industry inThailandare analyzed for a 20 year period (2000-2020) throughscenario analysis.
Seven scenarios were developed and analyzed, including a No Option scenario (NOP), a Business-As-Usual scenario (BAU) and five different Environment Policy scenarios (ENP), reflecting different strategies to reduce the environmental impact. These scenarios were analyzed with respect to their effectiveness in reducing the environmental pressure, and the associated costs. For each scenario, the overall environmental impact was calculated, and emissions were quantified for compounds that contribute to six environmental problems: global warming, acidification, eutrophication, smog, human toxicity and the production of waste.
The results indicate that without currently applied reduction options the environmental impact would be twice as high as it currently is. For the BAU scenario, in which no additional pollution reduction options are assumed to be implemented, the overall environmental impact was calculated to increase between 2000 and 2020 by a factor of two. The five Environmental Policy scenarios (ENP) reflect different strategies to reduce the environmental impact. The results indicate that, in the case of the ENP-M (theoretical maximum potential) scenario, it is theoretically possible to reduce the overall environmental impact by almost 50% relative to the BAU 2020 levels. This, however, may not be feasible because of the high costs involved. In the ENP-I (intermediate) scenario, for which cost-effectiveness is given a high priority, a 26% reduction in the overall environmental impact was calculated relative to the BAU scenario at almost 25% lower costs. This makes the ENP-I scenario the cheapest of the scenarios studied here. The other ENP scenarios reflectdifferent policy preferences for solvingenvironmental problems at the global (ENP-G), regional (ENP-R), and local (ENP-L) scale. The results for these scenarios indicate that 24-37% reduction of the overall impact relative to the BAU scenario can be achieved. This reflects that reduction of the overall environmental impact by about one-third relative to BAU scenario can be achieved through strategies which have a different focus. However, it is important to note that the costs of options implemented in these scenarios are different (cost of ENP-L> ENP-R> ENP-G).
Environmental systems analysis procedure
Environmental systems analysis (ESA) was found to be a useful procedure to analyzethe environmental pressure, identify options to reduce these pressures and evaluate their cost-effectiveness for the eucalyptus-based Kraft pulp industry inThailand. It was applied insix steps: 1)problem definition; 2) system definition; 3) system synthesis; 4) system analysis; 5) scenario analysis; and 6) presentation of results and implications for decision making. We have learned that this step-wise approach is not necessarily linear. Iterations were found to be needed to meet the objectives of the study.
Environmental indicators, life cycle assessment (LCA), multi-criteria analysis (MCA), cost-effectiveness analysis and scenario analysis, have been proved to be essential tools for the analysis in this thesis. First, environmental indicators and LCAwere combined to define the system boundary and quantify the environmental pressure ofeucalyptus-based Kraft pulp industry. Next, the model, used to quantify the potential environmental impact and evaluate the reduction option, was developed based on LCA, MCA and cost effectiveness approaches. Finally, scenario analysis appeared a powerful tool to analyzethe possible future consequences of different strategies to reduce the potential environmental impact ofthe eucalyptus-based Kraft pulp industry inThailand.
Novel aspects of this study not only include a better understanding of eucalyptus-based Kraft pulp production in Thailand, but also an improved insight in the usefulness of systems analysis tools for evaluating environmental policies in Thailand. The application of environmental systems analysis is based on a unique combination of tools applied to a case inThailand
. This contributes to the further development of environmental systems analysis and increase the understanding to the applicability of environmental systems analysis tools.