The value of information for managing contaminated sediments.

Effective management of contaminated sediments is important for long-term human and environmental health, but site-management decisions are often made under high uncertainty and without the help of structured decision support tools. Potential trade-offs between remedial costs, environmental effects, human health risks, and societal benefits, as well as fundamental differences in stakeholder priorities, complicate decision making. Formal decision-analytic tools such as multicriteria decision analysis (MCDA) move beyond ad hoc decision support to quantitatively and holistically rank management alternatives and add transparency and replicability to the evaluation process. However, even the best decisions made under uncertainty may be found suboptimal in hindsight, once additional scientific, social, economic, or other details become known. Value of information (VoI) analysis extends MCDA by systematically evaluating the impact of uncertainty on a decision. VoI prioritizes future research in terms of expected decision relevance by helping decision makers estimate the likelihood that additional information will improve decision confidence or change their selection of a management plan. In this study, VoI analysis evaluates uncertainty, estimates decision confidence, and prioritizes research to inform selection of a sediment capping strategy for the dibenzo-p-dioxin and -furan contaminated Grenland fjord system in southern Norway. The VoI model extends stochastic MCDA to model decisions with and without simulated new information and compares decision confidence across scenarios with different degrees of remaining uncertainty. Results highlight opportunities for decision makers to benefit from additional information by anticipating the improved decision confidence (or lack thereof) expected from reducing uncertainties for each criterion or combination of criteria. This case study demonstrates the usefulness of VoI analysis for environmental decisions by predicting when decisions can be made confidently, for prioritizing areas of research to pursue to improve decision confidence, and for differentiating between decision-relevant and decision-irrelevant differences in evaluation perspectives, all of which help guide meaningful deliberation toward effective consensus solutions.

Environmental and socioeconomic impacts of utilizing waste for biochar in rural areas in Indonesia--a systems perspective.

Biochar is the product of incomplete combustion (pyrolysis) of organic material. In rural areas, it can be used as a soil amendment to increase soil fertility. Fuel-constrained villagers may however prefer to use biochar briquettes as a higher-value fuel for cooking over applying it to soils. A systems-oriented analysis using life cycle assessment (LCA) and cost benefit analysis (CBA) was conducted to analyze these two alternative uses of biochar, applying the study to a rural village system in Indonesia. The results showed soil amendment for enhanced agricultural production to be the preferential choice with a positive benefit to the baseline scenario of -26 ecopoints (LCA) and -173 USD (CBA) annually pr. household. In this case, the positive effects of carbon sequestration to the soil and the economic value of the increased agricultural production outweighed the negative environmental impacts from biochar production and the related production costs. Use of biochar in briquettes for cooking fuel yielded negative net effects in both the LCA and CBA (85 ecopoints and 176 USD), even when positive health effects from reduced indoor air pollution were included. The main reasons for this are that emissions during biochar production are not compensated by carbon sequestration and that briquette making is labor-intensive. The results emphasize the importance of investigating and documenting the carbon storage effect and the agricultural benefit in biochar production-utilization systems for a sustainable use. Further research focus on efficient production is necessary due to the large environmental impact of biochar production. In addition, biochar should continue to be used in those soils where the agricultural effect is most beneficial.

Life cycle assessment to evaluate the environmental impact of biochar implementation in conservation agriculture in Zambia.

Biochar amendment to soil is a potential technology for carbon storage and climate change mitigation. It may, in addition, be a valuable soil fertility enhancer for agricultural purposes in sandy and/or weathered soils. A life cycle assessment including ecological, health and resource impacts has been conducted for field sites in Zambia to evaluate the overall impacts of biochar for agricultural use. The life cycle impacts from conservation farming using cultivation growth basins and precision fertilization with and without biochar addition were in the present study compared to conventional agricultural methods. Three different biochar production methods were evaluated: traditional earth-mound kilns, improved retort kilns, and micro top-lit updraft (TLUD) gasifier stoves. The results confirm that the use of biochar in conservation farming is beneficial for climate change mitigation purposes. However, when including health impacts from particle emissions originating from biochar production, conservation farming plus biochar from earth-mound kilns generally results in a larger negative effect over the whole life cycle than conservation farming without biochar addition. The use of cleaner technologies such as retort kilns or TLUDs can overcome this problem, mainly because fewer particles and less volatile organic compounds, methane and carbon monoxide are emitted. These results emphasize the need for a holistic view on biochar use in agricultural systems. Of special importance is the biochar production technique which has to be evaluated from both environmental/climate, health and social perspectives.

Use of stochastic multi-criteria decision analysis to support sustainable management of contaminated sediments.

Sustainable management of contaminated sediments requires careful prioritization of available resources and focuses on efforts to optimize decisions that consider environmental, economic, and societal aspects simultaneously. This may be achieved by combining different analytical approaches such as risk analysis (RA), life cycle analysis (LCA), multicriteria decision analysis (MCDA), and economic valuation methods. We propose the use of stochastic MCDA based on outranking algorithms to implement integrative sustainability strategies for sediment management. In this paper we use the method to select the best sediment management alternatives for the dibenzo-p-dioxin and -furan (PCDD/F) contaminated Grenland fjord in Norway. In the analysis, the benefits of health risk reductions and socio-economic benefits from removing seafood health advisories are evaluated against the detriments of remedial costs and life cycle environmental impacts. A value-plural based weighing of criteria is compared to criteria weights mimicking traditional cost-effectiveness (CEA) and cost-benefit (CBA) analyses. Capping highly contaminated areas in the inner or outer fjord is identified as the most preferable remediation alternative under all criteria schemes and the results are confirmed by a probabilistic sensitivity analysis. The proposed methodology can serve as a flexible framework for future decision support and can be a step toward more sustainable decision making for contaminated sediment management. It may be applicable to the broader field of ecosystem restoration for trade-off analysis between ecosystem services and restoration costs.

Evaluation of factors affecting stakeholder risk perception of contaminated sediment disposal in Oslo harbor.

The management of environmental pollution has changed considerably since the growth of environmental awareness in the late 1960s. The general increased environmental concern and involvement of stakeholders in today's environmental issues may enhance the need to consider risk in a much broader social context rather than just as an estimate of ecological hazard. Risk perception and the constructs and images of risks held by stakeholders and society are important items to address in the management of environmental projects, including the management of contaminated sediments. Here we present a retrospective case study that evaluates factors affecting stakeholder risk perception of contaminated sediment disposal that occurred during a remediation project in Oslo harbor, Norway. The choice to dispose dredged contaminated sediments in a confined aquatic disposal (CAD) site rather than at a land disposal site has received a lot of societal attention, attracted large media coverage, and caused many public discussions. A mixed method approach is used to investigate how risk perceptive affective factors (PAF), socio-demographic aspects, and participatory aspects have influenced the various stakeholders' preferences for the two different disposal options. Risk perceptive factors such as transparency in the decision making process and controllability of the disposal options have been identified as important for risk perception. The results of the study also support the view that there is no sharp distinction in risk perception between experts and other parties and emphasizes the importance of addressing risk perceptive affective factors in similar environmental decision-making processes. Indeed, PAFs such as transparency, openness, and information are fundamental to address in sensitive environmental decisions, such as sediment disposal alternatives, in order to progress to more technical questions such as the controllability and safety.

Use of life cycle assessments to evaluate the environmental footprint of contaminated sediment remediation.

Ecological and human risks often drive the selection of remedial alternatives for contaminated sediments. Traditional human and ecological risk assessment (HERA) includes assessing risk for benthic organisms and aquatic fauna associated with exposure to contaminated sediments before and after remediation as well as risk for human exposure but does not consider the environmental footprint associated with implementing remedial alternatives. Assessment of environmental effects over the whole life cycle (i.e., Life Cycle Assessment, LCA) could complement HERA and help in selecting the most appropriate sediment management alternative. Even though LCA has been developed and applied in multiple environmental management cases, applications to contaminated sediments and marine ecosystems are in general less frequent. This paper implements LCA methodology for the case of the polychlorinated dibenzo-p-dioxins and -furans (PCDD/F)-contaminated Grenland fjord in Norway. LCA was applied to investigate the environmental footprint of different active and passive thin-layer capping alternatives as compared to natural recovery. The results showed that capping was preferable to natural recovery when analysis is limited to effects related to the site contamination. Incorporation of impacts related to the use of resources and energy during the implementation of a thin layer cap increase the environmental footprint by over 1 order of magnitude, making capping inferior to the natural recovery alternative. Use of biomass-derived activated carbon, where carbon dioxide is sequestered during the production process, reduces the overall environmental impact to that of natural recovery. The results from this study show that LCA may be a valuable tool for assessing the environmental footprint of sediment remediation projects and for sustainable sediment management.

Environmental and economic impacts of biochar production and agricultural use in six developing and middle-income countries.

The feasibility of using biowaste for the production of biochar and its use in agriculture depends on its environmental and economic performance. This paper quantifies environmental and economic life cycle impacts of biochar production and agricultural use in six developing and middle-income countries (Ethiopia, Indonesia, Kenya, Peru, Vietnam, and China). Two types of production technologies typical for rural and urban areas were investigated (flame curtain kiln and gasifier, respectively), and comparisons were made with composting (either home composting or windrow composting) as alternative biowaste management systems. The results showed that both pyrolysis systems performed better than composting and both were expected to bring environmental benefits. The largest environmental benefits were observed for the gasifier systems, mainly due to the substitution of electricity production from the grid. Damage to ecosystems and human health ranged from -1 × 10-7 to -2 × 10-8 species×yr and from -1 × 10-5 to -5 × 10-6 DALY per kg of biowaste treated, respectively (negative scores indicating environmental benefits). However, net economic benefits were only achieved when low-cost simple kilns were used in countries with low labor cost, like Ethiopia, Kenya and Vietnam (net profit from 0.01 to 0.08 USD per kg of biowaste treated). Further, high investment and operating costs and relatively small electricity revenue from substituting the grid electricity resulted in gasifier scenarios being economically unsustainable (net loss from 0.29 to 1.58 USD per kg of biowaste treated). Thus, there are trade-offs between positive environmental impacts for society and net market loss for the individual decision-maker (company or individual farmer) that should be considered when making decisions regarding the implementation of biochar technology in developing and middle-income countries. The use of simple kilns in countries with relatively low labor costs appears to be favorable.

The importance of sulphide binding for leaching of heavy metals from contaminated Norwegian marine sediments treated by stabilization/solidification.

Over time, Norwegian fjords and harbour areas have received contaminants from industrial activities and urban run-off, and measures to remediate contaminated marine sediments are therefore needed. Stabilization/solidification (S/S) technology, in which the contaminated marine sediments are mixed with cement and other binding agents, has been shown to be a promising remediation technology. This paper summarizes a study of the environmental effect of stabilization, highlighting the importance of sulphide binding governing the leaching of heavy metals from the S/S of contaminated marine sediments. The study is a part of a research project focusing on developing effective methods for S/S of contaminated seabed sediments for use in new construction areas. Four cementitious binders were tested on sediments from six different locations: Bergen, Gilhus, Grenland, Hammerfest, Sandvika and Trondheim. The sediments differed with respect to properties such as concentration of contaminants, water content, organic content and grain size distribution. Portland cement, Portland cement with fly ash, industry cement, and sulphate resistant cement, were tested as binders. The leaching from the S/S sediments after 28 days of curing was measured by using a standard leaching batch test (EN 12457-2: 2003), with seawater as leaching agent. The eluate was analysed for pH and redox, as well as content of heavy metals and organic contaminants. Available volatile sulphide (AVS) and simultaneously extractable metals (SEM) were also measured in the sediments. This paper focuses on the leaching of lead (Pb) and copper (Cu). A reduced leaching of Pb after stabilization was observed for the mixtures, whereas the leaching of Cu from Hammerfest sediments increased substantially after stabilization for all cementitious additions. Experiments show that Hammerfest samples had lower values of AVS than the other sediments. This was confirmed by the SEM/AVS analysis, highlighting the importance of sulphide binding for mobility of heavy metals in stabilized marine sediments. For practical application of S/S technology to contaminated sediments, it is important to assess the leachability of the stabilized material taking sediment conditions such as AVS content into account. It is however important to be aware that the mobility of contaminants from a S/S sediment is dependent on a combination of contaminant concentrations and hydraulic conductivity (permeability). When devising S/S procedures for environmental projects, in addition to physical strength, the binder should be optimized in relation to leaching and permeability in order to achieve the lowest transport of contaminants through the material.

The mass flow and proposed management of bisphenol A in selected Norwegian waste streams.

Current initiatives for waste-handling in a circular economy favor prevention and recycling over incineration or landfilling. However, the impact of such a transition on environmental emissions of contaminants like bisphenol A (BPA) during waste-handling is not fully understood. To address this, a material flow analysis (MFA) was constructed for selected waste categories in Norway, for which the amount recycled is expected to increase in the future; glass, vehicle, electronic, plastic and combustible waste. Combined, 92tons/y of BPA are disposed of via these waste categories in Norway, with 98.5% associated with plastic and electronic waste. During the model year 2011, the MFA showed that BPA in these waste categories was destroyed through incineration (60%), exported for recycling into new products (35%), stored in landfills (4%) or released into the environment (1%). Landfilling led to the greatest environmental emissions (up to 13% of landfilled BPA), and incinerating the smallest (0.001% of incinerated BPA). From modelling different waste management scenarios, the most effective way to reduce BPA emissions are to incinerate BPA-containing waste and avoid landfilling it. A comparison of environmental and human BPA concentrations with CoZMoMAN exposure model estimations suggested that waste emissions are an insignificant regional source. Nevertheless, from monitoring studies, landfill emissions can be a substantial local source of BPA. Regarding the transition to a circular economy, it is clear that disposing of less BPA-containing waste and less landfilling would lead to lower environmental emissions, but several uncertainties remain regarding emissions of BPA during recycling, particularly for paper and plastics. Future research should focus on the fate of BPA, as well as BPA alternatives, in emerging reuse and recycling processes, as part of the transition to a circular economy.

Emissions and Char Quality of Flame-Curtain "Kon Tiki" Kilns for Farmer-Scale Charcoal/Biochar Production.

FLAME CURTAIN BIOCHAR KILNS: Pyrolysis of organic waste or woody materials yields charcoal, a stable carbonaceous product that can be used for cooking or mixed into soil, in the latter case often termed "biochar". Traditional kiln technologies for charcoal production are slow and without treatment of the pyrolysis gases, resulting in emissions of gases (mainly methane and carbon monoxide) and aerosols that are both toxic and contribute to greenhouse gas emissions. In retort kilns pyrolysis gases are led back to a combustion chamber. This can reduce emissions substantially, but is costly and consumes a considerable amount of valuable ignition material such as wood during start-up. To overcome these problems, a novel type of technology, the Kon-Tiki flame curtain pyrolysis, is proposed. This technology combines the simplicity of the traditional kiln with the combustion of pyrolysis gases in the flame curtain (similar to retort kilns), also avoiding use of external fuel for start-up. BIOCHAR CHARACTERISTICS: A field study in Nepal using various feedstocks showed char yields of 22 ± 5% on a dry weight basis and 40 ± 11% on a C basis. Biochars with high C contents (76 ± 9%; n = 57), average surface areas (11 to 215 m(2) g(-1)), low EPA16-PAHs (2.3 to 6.6 mg kg(-1)) and high CECs (43 to 217 cmolc/kg)(average for all feedstocks, mainly woody shrubs) were obtained, in compliance with the European Biochar Certificate (EBC). GAS EMISSION FACTORS: Mean emission factors for the flame curtain kilns were (g kg(-1) biochar for all feedstocks); CO2 = 4300 ± 1700, CO = 54 ± 35, non-methane volatile organic compounds (NMVOC) = 6 ± 3, CH4 = 30 ± 60, aerosols (PM10) = 11 ± 15, total products of incomplete combustion (PIC) = 100 ± 83 and NOx = 0.4 ± 0.3. The flame curtain kilns emitted statistically significantly (p<0.05) lower amounts of CO, PIC and NOx than retort and traditional kilns, and higher amounts of CO2. IMPLICATIONS: With benefits such as high quality biochar, low emission, no need for start-up fuel, fast pyrolysis time and, importantly, easy and cheap construction and operation the flame curtain technology represent a promising possibility for sustainable rural biochar production.

Use of multicriteria involvement processes to enhance transparency and stakeholder participation at Bergen Harbor, Norway.

Use of participatory stakeholder engagement processes could be important to reduce the risk of potential conflicts in managing contaminated sites. Most stakeholder engagement techniques are qualitative in nature and require experienced facilitators. This study proposes a multicriteria involvement process to enhance transparency and stakeholder participation and applies it to a contaminated sediment management case study for Bergen Harbor, Norway. The suggested multicriteria involvement process builds on the quantitative principles of multicriteria decision analysis and also incorporates group interaction and learning through qualitative participatory methods. Three different advisory groups consisting of local residents, local stakeholders, and nonresident sediment experts were invited to participate in a stakeholder engagement process to provide consensual comparative advice on sediment remediation alternatives. In order for stakeholders or residents to be able to embrace a complex decision such as selection of remediation alternatives, the involvement process with lateral learning, combined with multicriteria decision analysis providing structure, robustness and transparent documentation was preferable. In addition, a multicriteria involvement process resulted in consistent ranking of remediation alternatives across residents, stakeholder, and experts, relative to individual intuitive ranking without the multicriteria involvement process.

From ecological risk assessments to risk governance: evaluation of the Norwegian management system for contaminated sediments.

Managing of contaminated sediments is a complex process that will naturally have to balance scientific, political, and economic interests. This study evaluates the Norwegian system for managing contaminated sediments toward a generic system for risk governance encompassing both knowledge, legally prescribed procedures, and social values. The review has been performed examining the management plans for 17 prioritized contaminated fjord systems in Norway. The results indicate a strong focus in the Norwegian management system on ecological risk assessment. This facilitates selection of local sustainable remediation measures, but may also complicate the balance toward other relevant interests in a decision-making process. The Norwegian system lacks management tools to identify and handle ambiguity through concern assessments and stakeholder involvement, and the decision-making process seems to a large extent based on ad hoc decisions, making it difficult to incorporate and document multicriteria evaluations into the management process. To develop a sustainable management system, encompassing environmental, economical, and social interests, a stronger focus on concern assessment and multicriteria evaluations is required.