Marine Aquatic Ecotoxicity Potential Research Articles

Life cycle assessment of electricity generation by tire pyrolysis oil

The disposal of used vehicle tires at the end of their life time, is a significant environmental concern. There is need for specific legislative framework, regulating their disposal, after these are replaced, however, there are several options for further processing. In the framework of circular economy, recovery methods and new applications for the material are available. This paper examines the life cycle environmental impacts of the pyrolysis of End of Life (EoL) tires and the use of the produced Tire Pyrolysis Oil (TPO) for generation, presenting a Life Cycle Assessment (LCA) for a 17.8 MW designed generation unit in Cyprus. The boundaries of the system under study start from the receipt of shredded used tyres, and include the pyrolysis process, the electricity generation and the management of by-products, pollutants and waste for a case study about a unit designed to operate in Cyprus. Two Functional Units (FU) are used, 1 Kg of TPO and 1 MWh of produced electricity. A detailed Life Cycle Inventory (LCI) is presented and moreover, by applying the CML 2001 impact characterization method, the magnitude of a number of characterization factors are calculated for both of them. These results are compared to the respective of Light Fuel Oil (LFO) and of Cyprus grid electricity as alternatives. While, the TPO found to have lower environmental impact than LFO for all the impact categories, the production of electricity at the unit cause higher potential of depletion of abiotic resources – elements and marine aquatic ecotoxicity potential than the grid electricity. Specifically, the first, for 1 MWh produced in the unit under study, is 0.00026 kg antimony eq. and the second 171666.4 kg 1,4-dichlorobenzene eq., while for 1 MWh of Cyprus grid electricity they are 0.00013 kg antimony eq. and 136095.2 kg 1,4-dichlorobenzene eq., respectively. A contribution analysis, for these two impact categories is presented, showing that the use of urea and the production of solid waste to the unit contributes the most to both plus the exhaust gases to the second, therefore specific suggestions to minimize the contribution are formulated, available to be exploited for similar units. Moreover, concluding that the TPO use for generation could be an advantageous environmental option, recommendations for its strategic adoption are also made.

An Environmental Impact Assessment of Largemouth Bass (Micropterus salmoides) Aquaculture in Hangzhou, China

With the rapid increase in aquaculture production, its role in food safety and nutritional security has become increasingly important, but this has also given rise to environmental problems that cannot be ignored. The largemouth bass (Micropterus salmoides) has become a widely cultivated and highly economic freshwater farmed species since it was introduced to China in 1983; however, the environmental impacts of its freshwater pond aquaculture process have not yet been elucidated. Here, life cycle assessment (LCA), a decision-making tool that can evaluate and identify environmental issues during production processes, was used to evaluate the environmental performance of the largemouth bass freshwater pond aquaculture process, and a large-scale, commercial company was selected as an example in Hangzhou, China. The results showed that the pond-farming stage and marine aquatic ecotoxicity potential (MAETP) had the largest environmental impacts on the entire aquaculture process. An environmental contribution analysis indicated that electricity (48%) and emissions (23%) were two key factors in the seed-rearing stage, and electricity (60%) and feeds (26%) were two main impact contributors in the pond-farming stage. Improvement measures based on emerging technologies in aquaculture were discussed, namely, clean energies, industrial pond farming, and intelligent feeding strategies, to help with decision making for continuous improvement in the environmental performance of largemouth bass pond farming. Moreover, suggestions for further aquaculture LCA studies in China were summarized, as they will provide a useful reference for promoting the development of China’s aquaculture LCA research and the enrichment of the world’s aquaculture life cycle inventory databases.

Analysis of the life cycle environmental impact reductions of remanufactured turbochargers

Recently, remanufacturing approach/technology, which includes a series of the processes of disassembling, cleaning, inspecting, repairing/reconditioning, reassembling components for resale, is becoming more popular as companies look for a way to combat the current climate crisis, and as it allows companies to reduce environmental impacts and to save energy and resources. This study analyzed the reduction effect of six environmental impacts and the savings effect of energy and resources by turbocharger remanufacturing compared to its newly manufacturing using a life cycle assessment (LCA) methodology. The results show that the most significant benefit of the turbocharger remanufacturing related to environmental impacts was the global warming potential (GWP), which could be reduced by 52.2%, followed by the abiotic depletion potential (ADP), terrestrial ecotoxicity potential (TETP), human toxicity potential (HTP), freshwater aquatic ecotoxicity potential (FAETP) and marine aquatic ecotoxicity potential (MAETP) which could be reduced by 51.9%, 44.8%, 44.2%, 42.6%, and 36.7%, respectively. Also, its resource saving could be obtained from 21.7 to 73.5% depending on the type of resources. Furthermore, turbocharger remanufacturing offered a significant energy saving of 83.9%. The results obtained from this study could be used for national policy-making to a net-zero carbon transition.

Life cycle assessment (LCA) of marine microalgae cultivation and harvesting process for the Indian context

Microalgae cultivation is one of the emerging CO2 mitigation technologies and converting it into valuable products. The present study evaluates the environmental impacts of marine microalgae's cultivation and harvesting process with a cradle-to-gate approach from an Indian context. The algal cultivation site of 1000 acres is assumed to be located near the Indian coastal area. The life cycle inventory (LCI) data related to the site was assumed based on the literature. The functional unit (FU) for the present study was one kg of dried algae. The evaluation showed that the algal-based technology could mitigate about 1.28 kg CO2 eq./kg algae produced. Among all the impacts, marine aquatic ecotoxicity potential (MAETP) was found to be the most significant one, at 612 kg 1,4-dichlorobenzene (DCB) eq./kg algae. The major contributor to MAETP was the source of electricity. To take into account the uncertainties in the LCI, a scenario analysis was performed with the lower and higher possible process data. The global warming potential (GWP) for 35 g/m2 day productivity was −1.34 kg CO2 eq./kg algae, and for 15 g/ m2 day was −1.11 kg CO2 eq. against −1.28 kg CO2 eq. for the base case. For harvesting the feed concentration of 0.25 g/L, GWP was −0.98 kg CO2 eq./kg algae, and for 0.75 g/L, GWP was −1.39 kg CO2 eq./kg algae. For the consumption change of ±50% in electricity, the change in GWP was ± 13.85%. Further, a scenario analysis based on the source of electricity was evaluated. Replacing 25%, 50%, and 100% of Indian mixed grid electricity with solar-based electricity resulted in improvement in CO2 mitigation by 6%, 12%, and 24%, respectively. Additionally, a significant improvement in MAETP and human toxicity potential (HTP) was observed, with a reduction in MAETP by 20%, 40%, and 80% and HTP by 17%, 35%, and 70% for 25%, 50%, and 100% solar-based electricity respectively.

Environmental impacts of corn silage production: influence of wheat residues under contrasting tillage management types

The intensification of specific land management operations (tillage, herbicide, etc.) is increasing land degradation and contributing to ecosystem pollution. Mulches can be a sustainable tool to counter these processes. This is particularly relevant for rural areas in low-income countries where agriculture is a vital sector. In this research, the environmental impact of different rates of wheat residues (no residues, 25, 50, 75, and 100%) in corn silage cultivation was evaluated using the life cycle assessment (LCA) method under conventional tillage (CT) and no-tillage (NT) systems in a semi-arid region in Karaj, Iran. Results showed that in both tillage systems, marine aquatic ecotoxicity (ME) and global warming potential (GWP) had the highest levels of pollution among the environmental impact indicators. In CT systems, the minimum (17,730.70 kg 1,4-dichlorobenzene (DB) eq.) and maximum (33,683.97 kg 1,4-DB eq.) amounts of ME were related to 0 and 100% wheat residue rates, respectively. Also, in the CT system, 0 and 100% wheat residue rates resulted in minimum (176.72 kg CO2 eq.) and maximum (324.95 kg CO2 eq.) amounts of GWP, respectively. However, in the NT system, the 100% wheat residue rate showed the minimum amounts of ME (11,442.39 kg 1,4-DB eq.) and GWP (120.21 kg CO2 eq.). Also, in the NT system, maximum amounts of ME (17,174 kg 1,4-DB eq.) and GWP (175.60 kg CO2 eq.) were observed with a zero wheat residue rate. On-farm emissions and nitrogen fertilizers were the two factors with the highest contribution to the degradation related to environmental parameters at all rates of wheat residues. Moreover, in the CT system, the number of environmental pollutants increased with the addition of a higher wheat residue rate, while in the NT system, increasing residue rates decreased the amount of environmental pollutants. In conclusion, this LCA demonstrates that the NT system with the full retention of wheat residues (100%) is a more environmentally sustainable practice for corn silage production. Therefore, it may be considered one of the most adequate management strategies in this region and similar semi-arid conditions. Further long-term research and considering more environmental impact categories are required to assess the real potential of crop residues and tillage management for sustainable corn silage production.

Lifecycle Assessment of the Contact Smart Card Product in Indonesia

Smart Contact Cards have been widely used in Indonesia, especially in the banking sector. Bank Indonesia data shows an increase in the production of Card-Based Payment Instruments (APMK) consisting of Credit Cards, Debit Cards and Debit+ATM Cards. This is also followed by an increase in transactions using APMK from year to year. The large amount of contact Smart Card waste that is disposed of every year presents a major risk of environmental pollution. This study evaluates the potential environmental impact of the contact Smart Card product based on a life cycle assessment (LCA). The input data for all elements are obtained from the literature study with Gate-to-Gate System Constraints. The assessment was carried out with the help of OpenLCA v.1.8.0 software, ELCD 3.2 database and CML (Baseline) impact assessment method. The results of the analysis show that Marine aquatic ecotoxicity is a significant potential environmental impact with a magnitude of 96%, followed by Acidification and Human Toxicity. Each contact Smart Card has 62,04526 kg1,4-DBeq in Marine Aquatic Ecotoxicity Potential, 2,22473 kgSO2eq as Acidification Potential and 0.37285 kg1,4-DBeq as Human Toxicity Potential. Further examination also shows that most of the impact comes from the choice of materials used. Copper material as the main material for the chip module plays an important role in providing environmental impact.

Performance evaluation of the emerging rural sewage treatment facilities in China.

Urban water pollution has been well controlled by strict management in the past few decades in China. Thus, the central government started to place emphasis on rural water pollution, and increasing number of sewage treatment facilities have been constructed, and currently, they are operating in China. Therefore, thoroughly assessing the operating conditions and the performance of these facilities is important. This article analyzes life cycle assessment and life cycle cost to evaluate the environmental and economic performance of four common technologies to determine how the emerging rural sewage treatment facilities in China are running. The results showed that the plant-adopted anaerobic-anoxic-oxic process was an optimal scheme for lower environmental impact that was also cost-effective. All technologies had similar impacts on eleven environmental categories. Due to cement consumption during the construction phase and electricity consumption during the operation phase, the marine aquatic ecotoxicity potential was the greatest contributor, accounting for approximately 90% of the total potential impact. In addition, this research revealed that electricity consumption during the operation phase was responsible for almost all environmental impact categories, except for eutrophication potential and ozone layer depletion potential categories. Lastly, scenario analysis indicated that reusing treated water and adjusting power structure could be useful measures to promote the sustainable development of rural water environments.

Life cycle assessment and cost analysis for copper hydrometallurgy industry in China

Understanding the environmental and economic impacts of copper hydrometallurgy throughout the whole life cycle is necessary for sustainable development of the copper industry. In this study, the environmental impacts and economic costs throughout the two major copper hydrometallurgical routes in China, including heap leaching and heap-agitation leaching, are analyzed and compared using the life cycle assessment (LCA) and life cycle cost (LCC) technique. The life cycle inventory compiled from the annual statistics of the Muliashi Copper Mine, and the data regarding energy and materials process are based on the GaBi databases. The environmental impacts are quantified into 12 indicators. The results show that compared with heap leaching route, heap-agitation leaching route reduces 36.8% of abiotic depletion potential (ADP elements), but increases over half of cumulative energy demand (CED), marine aquatic ecotoxicity potential (MAETP) and human toxicity potential (HTP). Furthermore, the stage of electrowinning and agitation leaching contributes the largest environmental impact to heap leaching and heap-agitation leaching route, respectively. This is mainly due to huge consumption of electricity and sulfuric acid. The analysis of economic cost reveals that heap leaching route needs internal cost of $3225/t Cu and external cost of $426/t Cu. Compared with heap leaching route, heap-agitation leaching route increased the internal and external cost by 18.9% and 54.2%, respectively. But the economic return from heap-agitation leaching is double that from heap leaching. Together, these results indicate heap-agitation leaching has a larger environmental impact and higher economic benefit than heap leaching, which is helpful for the government to design ecological compensation policies in the balance between ecological environment and economic development.

Life cycle assessment of tiger puffer (Takifugu rubripes) farming: A case study in Dalian, China

In China, energy consumption and carbon emission by the aquaculture industry have become major problems. The tiger puffer (Takifugu rubripes) is an emerging aquaculture species in China, but its environmental impact during the farming process has not yet been evaluated systematically. To the best of our knowledge, this is the first life cycle assessment (LCA) of tiger puffer land-sea relay strategy in Dalian, China. To analyze the environmental impact of the tiger puffer farming process, the following four stages were considered: seed rearing, deep-sea cage farming-1, industrial recirculating aquaculture, and deep-sea cage farming-2. The LCA software GaBi 10.5 academy version and CML-IA-Jan. 2016-world method were used to calculate the environmental impacts. According to the LCA results, marine aquatic ecotoxicity potential was the largest contributor to the environmental impact, and industrial recirculating aquaculture was the largest farming stage in the whole tiger puffer farming process. Energy in the form of electricity, coal, and gasoline was consumed to maintain the power supply in the tiger puffer farming process, and it was a key factor that influenced the environmental performance. Based on the sensitivity and energy analyses, energy consumption for equipment operation at the industrial recirculating aquaculture stage, feed consumption, and gasoline consumption for transportation at the deep-sea cage farming-2 stage need to be carefully considered. The following improvement measures were suggested to improve the environmental performance of tiger puffer farming and the aquaculture industry: establish electricity, wind power, and solar energy integrated management systems; ex-ante LCA for parameter optimization in future technology research and development; and new production strategies such as aquaponics and integrated multi-trophic aquaculture. Moreover, life cycle inventory (LCI) of tiger puffer land-sea relay farming was established to obtain essential information, enrich aquaculture LCI databases, and support aquaculture LCA research.

Comparative environmental and economic life cycle assessment of dry and wet anaerobic digestion for treating food waste and biogas digestate

Anaerobic digestion (AD) has proven to be a promising option for food waste (FW) management, due to the significant potential of recovering energy from waste. In this study, the environmental and economic impacts of six scenarios for FW and biogas digestate management in Shenzhen, China, were evaluated using life cycle assessment (LCA) and life cycle cost (LCC) analysis. GaBi model was employed to perform LCA on the basis of CML 2001 methodology, while LCC analysis was conducted using net present value to evaluate the economic efficiency. Results showed that dry AD coupled with biogas digestate incineration not only exhibited the best net environmental benefits with the reduction of 195 kg CO2 per ton of FW, but also appeared to be the most economically feasible option with the lowest LCC (446.223 thousand CNY). With respect to the FW treatment technology, dry AD scenarios exhibited better environmental benefits associated with global warming, human toxicity, marine aquatic ecotoxicity and photochemical ozone creation potential, compared to those in wet AD. Regarding post treatment for biogas digestate, incineration appeared to be the best option compared to the landfill and compost. Moreover, sensitivity analysis indicated that dry AD coupled with biogas digestate incineration exhibited least vulnerable to the change in biogas production environmentally. The outcomes of this study will contribute to developing the optimal FW management strategy for mitigating the environmental and economic impacts in terms of both environmental and economic sustainability.

A Comparative Life Cycle Assessment (LCA) of Gasoline Blending with Different Oxygenates in India

This paper includes a cradle-to-gate life cycle impact evaluation of gasoline blends in India. The potential environmental impacts of gasoline blends with three major components, i.e., methanol, ethanol, and n-butanol are assessed. The production of methanol from the natural gas reforming process, ethanol from hydrogenation with nitric acid, and n-butanol from the oxo process are considered in the current study. The results show that the gasoline blending with methanol has the lowest impact (11 categories) and is nearly constant from 5 to 15%. For gasoline with ethanol as an additive, the global warming potential, ozone depletion potential, and abiotic depletion potential rise with increasing ethanol addition. Meanwhile, increasing ethanol addition reduces the acidification potential and terrestric ecotoxicity potential impact of gasoline blends. Similarly, gasoline with n-butanol as an additive has higher acidification potential, eutrophication potential, human toxicity potential, terrestric ecotoxicity potential, marine aquatic ecotoxicity potential, and photochemical ozone creation potential compared to methanol and ethanol.

Life Cycle Impact Assessment of Recycled Aggregate Concrete, Geopolymer Concrete, and Recycled Aggregate-Based Geopolymer Concrete

This study presents a life cycle impact assessment of OPC concrete, recycled aggregate concrete, geopolymer concrete, and recycled aggregate-based geopolymer concrete by using the mid-point approach of the CML 2001 impact-assessment method. The life cycle impact assessment was carried out using OpenLCA software with nine different impact categories, such as global warming potential, acidification potential, eutrophication potential, ozone depletion potential, photochemical oxidant formation, human toxicity, marine aquatic ecotoxicity, and freshwater and terrestrial aquatic ecotoxicity potential. Subsequently, a contribution analysis was conducted for all nine impact categories. The analysis showed that using geopolymer concrete in place of OPC concrete can reduce global warming potential by up to 53.7%. Further, the use of geopolymer concrete represents the reduction of acidification potential and photochemical oxidant formation in the impact categories, along with climate change. However, the potential impacts of marine aquatic ecotoxicity, freshwater aquatic ecotoxicity, human toxicity, eutrophication potential, ozone depletion potential, and terrestrial aquatic ecotoxicity potential were increased using geopolymer concrete. The increase in these impacts was due to the presence of alkaline activators such as sodium hydroxide and sodium silicate. The use of recycled aggregates in both OPC concrete and geopolymer concrete reduces all the environmental impacts.

Assessment of upgrading WWTP in southwest China: Towards a cleaner production

This work comprehensively assessed two scenarios of a WWTP (before and after upgrading, respectively) in southwest China, on the basis of their treatment performance, operational cost, energy demand, as well as environmental impacts. The scenario before upgrading adapted conventional anaerobic-aerobic system, whereas that of after upgrading improved the treatment scale and quality by expanding the biochemical tanks and elevating tertiary treatment with a membrane tank. Our results implied that the treatment performance of the WWTP was notably enhanced after upgrading, in particular, for chemical oxygen demand (COD) and nitrogen removal. The microbes responsible for nitrification and denitrification showed a relatively higher abundance compared with those before upgrading. In turn, energy demand and costs consumption per m3 of wastewater also increased. This increment was predominantly caused by the intensive energy load and the substantial uses of multiple chemicals in secondary and tertiary treatment without systematic optimization. Subsequently, environmental impacts were escalated in the scenario after upgrading. The dominating impact category in both scenarios was Marine Aquatic Ecotoxicity Potential (MAEP), whereas the Abiotic Depletion-fossil (ADP (fossil)) was also considerably affected after upgrading because of the increasing use of chemicals. The results indicate that upgrading the WWTP significantly improved the treatment performance, however, inevitably brought additional impacts as the scale enlarged accompanied by more unit input to meet the stringent treatment standards. Thus, actions and strategies are in need to balance trade-offs among treatment performance, energy and costs consumption, and environmental impacts for current and future projects towards a cleaner production.

The environmental performance of greenhouse versus open-field cherry production systems in China

Greenhouse farming increasingly has been adopted in China to provide off-season products because fruit and vegetable crops cannot be grown year-round. Compared with conventional open-field cultivation, however, greenhouse cultivation usually requires higher energy and material inputs for facility construction and interior heating, increasing the environmental burdens associated with product provision. Thus, the cradle-to-gate “time-environmental” trade-off of off-season products should be completely quantified to guide green consumption. In this study we employed the process-based life-cycle assessment modeling approach to estimate the environmental costs of greenhouse cherry cultivation and compared these costs with the impacts of open-field cultivation. We examined 10 impact categories, including the abiotic depletion of fossil fuel potential, global warming potential, acidification potential, eutrophication potential, ozone layer depletion, photochemical oxidation potential, fresh water aquatic ecotoxicity potential, marine aquatic ecotoxicity potential, terrestrial ecotoxicity potential, and human toxicity potential. The results show that the environmental impacts of greenhouse cherry cultivation are considerably higher (112.7% to 1672.5%) than those of open-field production, indicating significant environmental burdens associated with producing fresh cherries one to two months early. For greenhouse cherry production, interior heating was the hotspot in all impact categories, and fertilizer dominated the impacts of open-field cultivation. For greenhouse cherries, impact mitigation opportunities mainly were found in the adoption of cleaner heating fuel and animal manure use.

Environmental Performance Assessment of Batch Type Hot Mix Plant Using LCA

The environmental impacts from production of Hot Mix Asphalt (HMA) in batch Hot Mix Plant (HMP) has been evaluated using Life Cycle Assessment (LCA) methodology. The hot mix technology has been in use since long time for production of HMA used in construction of road pavements. The functional unit adopted is 100 tonnes of HMA production and CML 2001 method is used for assessment using GaBi 10.5. The study found that the production of HMA in batch HMP had very high environmental impacts on marine aquatic ecotoxicity potential (MAETP) impact category (8,25,573 kg DCB eq.), abiotic depletion fossil (ADP fossil) (2,87,295 MJ) impact category and global warming potential (GWP) impact category (2,770 kg CO2 eq.). The raw material phase had higher environmental impacts compared to production process phase on all the impact categories. It was also concluded that the use of renewable energy and fuel and adoption of cold mix technology will reduce the environmental impacts.

Environmental Impact Analysis of Automobile Laminated Glass Production

The rapid development of China’s automobile industry has led to increased demand for automobile glass. Combined with the present situation of China’s automobile glass industry, life cycle assessment(LCA) method was adopted for this study, through investigating the energy consumption and emissions during the raw and auxiliary materials acquisition stage and product production stage for auto laminated glass. Then a life cycle inventory was worked out and the data was characterized and normalized by CML analysis method. The results showed that the most serious environmental impacts were Marine Aquatic Ecotoxicity Potential, abiotic depletion potential-fossil and global warming potential, whose proportion of total environmental impact was 92.2%, 2.41%, 1.75%, respectively. Further analysis showed that the influence of float glass was 36%,42% and 33.9% respectively.

Quantifying the life cycle environmental impacts of water pollution control in a typical chemical industrial park in China

AbstractAs the most important production space for the development of chemical industry in China, chemical industrial parks (CIPs) are facing a new challenge of water pollution prevention and control, in addition to those posed by traditional and emerging pollutants. It is thus important to systematically reveal the compositewater‐environmental impact of CIPs for contributing to the sustainable development of the chemical industry. CIPs have the issue of intensive wastewater generation characterized by complex pollutant components and high pollution loads. Thus, establishing an environmentally friendly wastewater treatment system has always been a major challenge for CIPs. China has developed many CIPs and the two‐stage wastewater treatment system is widely employed in practice, that is, in‐plant wastewater treatment plants (WWTPs) in individual enterprises followed by centralized WWTPs in parks. Since the CIP wastewater emission limits are continuously improved, a comprehensive evaluation of the environmental impacts of the in‐use wastewater treatment system will be insightful for future policy making. This study employed life cycle assessment (LCA) to reveal the life cycle environmental impact of the two‐stage wastewater treatment system in a typical CIP. We found that the life cycle environmental impacts of the whole system mainly stem from the in‐plant WWTPs of chemical manufacturers because of chemicals and electricity consumed in the multi‐stage advanced oxidation technologies, while the increase of human toxicity potential and marine aquatic ecotoxicity potential are primarily due to sludge incineration. Three scenarios targeting the reduction of environmental impacts were proposed based on the LCA results. We evaluated the pollution mitigation potential, which can reach at most 8% of the original measured impacts. Finally, from the perspective of systematic thinking, four policy implications for improving the water management system of CIPs were proposed.

Combining Process Modelling and LCA to Assess the Environmental Impacts of Wastewater Treatment Innovations

Alternative wastewater treatment (WWT) technologies with lower environmental impacts seem to be the way forward in the pursuit of sustainable wastewater treatment plants (WWTPs). Process modelling of material and energy flows together with life-cycle assessment (LCA) can help to better understand these impacts and show the right direction for their development. Here, we apply this combined approach to three scenarios: conventional WWT; conventional WWT + chemically enhanced primary treatment (CEPT); conventional WWT + CEPT + side stream partial nitritation/anammox (PN/A). For each scenario, equations were developed to calculate chemical oxygen demand and nitrogen flow (solid and dissolved form) through the WWTP and to estimate the energy demands of its unit operations. LCA showed that the main environmental impact categories for all scenarios were global warming potential (GWP), eutrophication potential (EP) and marine aquatic eco-toxicity potential (MAETP). Compared with conventional WWT, CEPT and CEPT combined with PN/A resulted in a higher sum of normalized and weighed environmental indicators, by 19.5% and 16.4%, respectively (20.0% and 18.3% including biogenic carbon). Interestingly, the environmentally positive features of the alternative scenarios were often traded-off against other increased negative impacts. This suggests that further development is needed to consider these technologies a sustainable alternative.

Stabilising Rural Roads with Waste Streams in Colombia as an Environmental Strategy Based on a Life Cycle Assessment Methodology

Roads with low traffic volume link rural settlements together and connect them with urban centres, mobilising goods and agricultural products, and facilitating the transportation of people. In Colombia, most of these roads are in poor conditions, causing social, economic, and environmental problems, and significantly affecting the mobility, security, and economic progress of the country and its inhabitants. Therefore, it is essential to implement strategies to improve such roads, keeping in mind technical, economic, and environmental criteria. This article shows the results of the application of the environmental life cycle assessment—LCA—to sections of two low-traffic roads located in two different sites in Colombia: one in the Urrao area (Antioquia), located in the centre of the country; and another in La Paz (Cesar), located in the northeast of the country. Each segment was stabilised with alternative materials such as brick dust, fly ash, sulfonated oil, and polymer. The analysis was carried out in three stages: the first was the manufacture of the stabiliser; the second included preliminary actions that ranged from the search for the material to its placement on site; and the third was the stabilisation process, which included the entire application process, from the stabiliser to the road. The environmental impacts are mainly found in the manufacture of stabilisers (60% of the total), for sulfonated oil or polymer, due to the different compounds used during production, before their use as stabilisers. The impact categories with the greatest influence were abiotic depletion potential (ADP), global warming potential (GWP) and terrestrial ecotoxicity potential (TETP). For the stabilisation stage (impact between 40% and 99%), ash and brick dust have the highest impacts. The impact categories most influenced in this stage were: acidification potential (AP), freshwater aquatic ecotoxicity potential (FAETP), human toxicity potential (HTP), marine aquatic ecotoxicity potential (MAETP) and photochemical ozone creation potential (POCP).

Environmental-Economic Assessment of the Pressure Swing Adsorption Biogas Upgrading Technology

A large-scale biogas upgrading plant using the CarboTech® technology with a treatment capacity of 1333 Nm3 biogas per hour was analyzed. Our scope of evaluation encompasses all technology steps that are necessary for upgrading biogas, i.e., both pretreatment and biogas upgrade. A cradle-to-gate life-cycle and life-cycle cost assessment (LCA and LCCA) methodology was used with the functional unit (FU) of 1 Nm3 of biogas upgraded in order to ease comparison with other biogas upgrading technologies. The calculation was made using the GaBi8 LCA software and databases of GaBi Professional, Construction materials, Food&Feed, and the ecoinvent3. We applied the CML characterization model with all its mid-point indicators. The mid-point indicators of the CML characterization model were aggregated after normalization by the CML2001 - Jan.2016 normalization factors. The normalized environmental impact was 541.74·10−15/Nm3 raw biogas. The highest environmental impacts were the marine aquatic ecotoxicity potential (15.705 kg dichlorobenzene-equiv./Nm3 raw biogas), the abiotic depletion potential (1.037 MJ/Nm3 raw biogas), and global warming potential (0.113 kg CO2-equiv./Nm3 raw biogas). The unit production cost of the PSA technology was 0.05-0.063 €/Nm3 raw biogas. The most considerable source of expenses was the operational cost from which 77% was spent on electricity. The initial investment, personal costs, and the reinvestment amounted to only 34% of the total costs for the whole life cycle. Strategies to lower the environmental burden of the PSA technology are to use green electricity and to optimize the size of the plant in order to reduce unnecessary material flows of building material and their indirect energy use. This can also lower investment expenditures while automatization and remote control may spare personnel costs.