Minimizing greenhouse gas emissions through the application of solar thermal energy in industrial processes

The analysis of industrial energy usage indicates that low temperature processes (20 ≈ 200 °C) are used in nearly all industrial sectors. In principle there is the potential to use solar thermal energy in these lower temperature processes thus, reducing the environmental impact of burning fossil fuels. Using the model of an Austrian dairy plant, this research investigated the potential for, and the economic viability of, using solar energy heat processes in industry.Some industrial sectors such as food, chemistry, plastic processing, textile industry, building materials industry and business establishments can be identified as potential sectors for the application of solar energy heat processes. When assessing the (economic) feasibility of solar thermal energy, the investigation of these industries’ energy systems has to focus on an integrated analysis of cooling and heating demands and to take into account competing technologies. Amongst these are heat integration, cogeneration, new technologies and heat pumps. Pinch analysis was used to investigate industrial energy systems and heat integration possibilities and proved to be a viable tool. Working from the basis of energy balances, Sankey diagrams, pinch analysis and environmental cost accounting, a newly developed investigation tool was applied in the case study of an Austrian dairy plant. This enabled a fast optimization of the system. Two different options for the integration of solar thermal energy into the production line were calculated, option 1 with a solar field of 1000 m² and option 2 with a solar field of 1500 m². Natural gas savings of 85,000 for option 1 and 109,000 m³/a for option 2 can be achieved, resulting in a reduction of 170 tons of CO₂ per year, or 218 tons for options 1 and 2 respectively. Based upon option 1, return on investment is realised after less than three years of implementation. This research thus, indicates promising technical and economical feasibility of using solar thermal energy for industrial processes and provides an important step towards sustainable zero emission production in industry.     

LCA of spent fluorescent lamps in Thailand at various rates of recycling

This paper presents environmental impact of a fluorescent lamp (a long straight tube 36 watts, 200 g and 13,600 h for mean time before failure) when considering different disposal methods (recycle and non-recycle) of its spent fluorescent lamp (SFL). The study was applied for the case in Thailand using life cycle assessment (LCA) as a tool. All materials, energy use, and pollutant emissions to the environment from each related process were identified and analyzed. Impact assessment was conducted for 10 environmental impact potentials: carcinogens, respiratory organics, respiratory inorganics, climate change, radiation, ozone layer, ecotoxicity, acidification/eutrophication, land use and minerals. The analysis followed Eco-Indicator 99 method, individualist version 2.1. The main focus of the study was to compare the impact of SFL recycling with non-recycling before landfilling. The impact intermittent activities, production of raw material and energy used in all the concerned processes were taken into account. However, transportation activities were excluded. The results showed that for all recycling rates, cement production is the main contributor to the environmental impacts, while sodium sulfide production is second and electrical production, the third. Mercury vapor emission showed a small contribution in carcinogens and ecotoxicity. The impacts are reduced when recycling rate is increased. The reduction of cement consumption in disposal processes or the process improvement of cement production may also help to reduce environmental impacts.     

Comparing carbon fluxes between different stages of secondary succession of a karst grassland

Abandonment of marginal agricultural areas with subsequent secondary succession is a widespread type of land use change in Mediterranean and mountain areas of Europe, leading to important environmental consequences such as change in the water balance, carbon cycling, and regional climate. Paired eddy flux measurement design with grassland site and tree/shrub encroached site has been set-up in the Slovenian Karst (submediterranean climate region) to investigate the effects of secondary succession on ecosystem carbon cycling. The invasion of woody plant species was found to significantly change carbon balance shifting annual NEE from source to an evident sink. According to one year of data succession site stored ?126 ± 14 g C m^?2 y^?1 while grassland site emitted 353 ± 72 g C m^?2 y^?1. In addition, the seasonal course of CO₂ exchange differed between both succession stages, which can be related to differences in phenology, i.e. activity of prevailing plant species, and modified environmental conditions within forest fragments of the invaded site. Negligible effect of instrument heating was observed which proves the Burba correction in our ecosystems unnecessary. Unexpectedly high CO₂ emissions and large disagreement with soil respiration especially on the grassland site in late autumn indicate additional sources of carbon which cannot be biologically processes, such as degassing of soil pores and caves after rain events.     

Material flows in the life cycle of leather

This paper presents a study on the resource and environmental profile of leather for communicating to the consumers about the environmental burdens of leather products. The results indicate that significant environmental impacts were caused during the tanning and finishing of leather as well as the electricity production and transportation required in the life cycle. The use of fossil fuels in the production of energy has greater impact with increased emissions leading to about 15190 kg CO₂ equivalent of global warming and about 73 kg SO₂ equivalent of acidification while producing 100 m² of leather for shoe uppers. Further resource use of 174 kg of coal, 6.5 kg of fuel oil, 17.4 m³ of water and 348 kg of chemicals of which about 204 kg are hazardous are consumed, and wastewater of about 17 m³, BOD of 55 kg, COD of about 146 kg, TDS of 732 kg and solid waste of about 1445 kg are generated during the life cycle for the production of 100 m² of leather. The total solid waste generated is 1317 kg, out of which about 80% is biodegradable contributed by slaughtering, tanning and finishing stage, 14% is non-biodegradable contributed by tanning, finishing and electricity production stages and 6% is hazardous mainly from tanning and finishing stage of leather.     

Environmental consequences of different beef production systems in the EU

The aim of this paper is to examine the environmental consequences of beef meat production in the EU, using a life cycle approach. Four beef production systems were studied – three from intensively reared dairy calves and one from suckler herds. According to the results of the analysis, the contributions from the production of 1 kg beef meat (slaughter weight) to global warming, acidification, eutrophication, land use and non-renewable energy use were lower for beef from dairy calves than from suckler herds (16.0–19.9 versus 27.3 kg CO₂e, 101–173 versus 210 g SO₂e, 622–1140 versus 1651 g NO₃e, 16.5–22.7 versus 42.9 m²year, and 41.3–48.2 versus 59.2 MJ, respectively). The breakdown analysis helped identify the key areas in the “cradle to farm gate” beef production system where sustainable management strategies are needed to improve environmental performance. The study also included a sensitivity analysis to preliminarily estimate GHG emissions from beef production systems if land opportunity cost and land use change related to grazing and feed crop production for beef were taken into account. If so, the contribution from the production of 1 kg beef to global warming would increase by a factor of 3.1–3.9, based on a depreciation period of 20 years. This highlights the importance of taking into account the impacts of land use in assessing the environmental impacts of livestock production.     

The social and spatial distribution of temperature-related health impacts from urban heat island reduction policies

Cities are developing innovative strategies to combat climate change but there remains little knowledge of the winners and losers from climate-adaptive land use planning and design. We examine the distribution of health benefits associated with land use policies designed to increase vegetation and surface reflectivity in three US metropolitan areas: Atlanta, GA, Philadelphia, PA, and Phoenix, AZ. Projections of population and land cover at the census tract scale were combined with climate models for the year 2050 at 4 km × 4 km resolution to produce future summer temperatures which were input into a comparative risk assessment framework for the temperature-mortality relationship. The findings suggest disparities in the effectiveness of urban heat management strategies by age, income, and race. We conclude that, to be most protective of human health, urban heat management must prioritize areas of greatest population vulnerability.     

Use of life cycle assessment methodology for determining phytoremediation potentials of maize-based cropping systems in fields with nitrogen fertilizer over-dose

Using the life cycle assessment (LCA) method, we analyzed the effects of different cropping systems (sole maize (CK), maize + soybean (CST) and maize + groundnut (CGT)) on the environment. The comprehensive index of environmental impacts varied in the order, sole maize > maize + groundnut > maize + soybean, with corresponding intercropping values of 0.1295, 0.1229 and 0.0945, respectively. The results showed that intercropping maize with suitable plants (e.g., groundnut and soybean) could reduce the adverse effects of over-application of nitrogen fertilizer on the environment. The study further showed that the LCA method may be a convenient and effective approach for analyzing the environmental impact of fertilizer management in agricultural fields.     

Utilisation of phosphorus nutrient content in industrial scale plasmid DNA production: a waste minimisation study

Human gene therapy is currently seeing an increase in the use of plasmid (pDNA)-based vectors as a preferred choice of vehicle for delivery of the therapeutic gene into the body. In this regard, the environmental impacts of the waste streams from the possible industrial scale manufacture of pDNA require more detailed assessment. In this study, an initial assessment was made of the nutrient phosphorus (P) inputs to four fermentation processes recommended for the industrial scale production of pDNA for the purposes of gene therapy. Phosphorus inputs to each of the four selected fermentation processes ranged from approximately 60 mg l^?1 up to 3000 mg l^?1 in the fresh media. However, the spent media waste from each of the processes exhibited only a minor reduction in the phosphorus concentrations indicating minimal uptake of P by the microorganisms. This unutilised excess level of phosphorus nutrient within the waste streams poses a strong potential for environmental impact. Waste minimisation studies were undertaken on one model fermentation process with the aim of reducing unnecessary phosphorus input. An optimised media containing a 98% reduction in added P to the media was developed. This phosphorus-minimised media had little quantitative effect upon cell biomass produced and no effect upon the quantity or quality of pDNA produced, relative to the control media. The reduction in P requirement results in an overall cost savings of 12% per fermentation batch, would simplify subsequent wastewater treatment and would contribute to slowing the depletion rate of a valuable, finite natural resource.     

Aero-lap polishing of poly crystalline diamond inserts using Multicon media

Increasing use of poly crystalline diamond (PCD) inserts as cutting tools and wear parts is vividly seen in automobile, aerospace, marine and precision engineering applications. The PCD inserts undergo series of manufacturing processes such as: grinding that forms the required shape and polishing that gives a fine finish. These operations are not straight forward as PCD is extremely resistant to grinding and polishing. Single crystal diamond can easily be polished by choosing a direction of easy abrasion, but polishing a PCD imposes serious difficulties as the grains are randomly oriented. Prior research on polishing of PCD inserts includes electro discharge grinding (EDG), dynamic friction polishing and grinding by a vitrified bonded diamond wheel. The surface textures of PCD produced using an EDG process often contains: micro cavities, particle pullout, micro-grooves, chipped edges, cracks and gouch marks. While applying the dynamic friction polishing method the PCD material undergoes phase transformation and hence increased polishing rate was apparently seen. However the phase transformation of PCD deteriorates the strength of the insert. Furthermore the inserts produced using the dynamic polishing method often exhibits cracks, chip off and edge damage while using as a cutting tool. Therefore, a new method “aero-lap polishing” was attempted as it applies controlled amount of impinging force by which the surface damage can be significantly reduced. The study did establish an improvement of surface finish of PCD from R_a = 0.55 μm, R_t = 4.5 μm to R_a = 0.29 μm, R_t = 1.6 μm within 15–25 min of polishing time along with significant reduction in surface defects.     

The precautionary principle and environmental persistence: prioritizing the decision-making process

There is continuing activity among regulatory bodies to assess and prioritize chemicals used in commerce based on their potential to be persistent, bioaccumulative, and toxic (PBT). Reliable data needed to perform a PBT hazard or risk assessment, however, may not always be readily available. Consequently concern may arise regarding the potential for false positives and false negatives to be wrongly classified. In order to more effectively classify substances, adequate time is needed to acquire the necessary data to support the overall PBT assessment. Of particular interest is the question of whether or not restrictions on the use and manufacture of a substance can be delayed to allow time to conduct the necessary field and laboratory studies of a particular substance? To address this question it is demonstrated that chemical partitioning property and environmental persistence information can be effectively combined to provide guidance for regulatory priority setting. Specifically, it is argued that substances that have media specific half-life values that exceed the regulatory threshold value for persistence under the EU chemicals REACH program, for example, are more likely to have a ‘legacy’ associated with their use when the log K_OA > 8, and when they are emitted to air or soil. Thus, precautionary actions limiting the use and manufacture of the substance may be warranted. Whereas substances emitted to air with log K_OA < 6 and log K_AW > ?2 are less likely to have a ‘legacy’ associated with their use. Thus precautionary actions in the absence of data may not be warranted.     

Study on machinability of a stellite alloy with uncoated and coated carbide tools in turning

Stellite alloys, which have been widely used in the aerospace, automotive and chemical industries, are hard-to-cut cobalt-based materials. This study investigates the machinability of stellite 12 alloys with uncoated carbide cutting tool grades YG610 (K01-K10) and YT726 (K05-K10/M20) and SANDVIK coated carbide tool SNMG150612-SM1105 under dry cutting conditions. Both wear mechanisms and failure modes of the uncoated and coated tools were investigated with turning experiments. The results show that the coated tool SM1105 remarkably outperforms the uncoated tools; and the cutting tool YG610 generally outperforms YT726 under all cutting conditions. Built-up edge was found with YG610 in some cutting conditions and with SM1105 at cutting speed of 16 m/min. Tool surface burning marks were observed on YT726 at relatively higher cutting speeds. Wear develops slowly with coated tools SM1105 until VB reaches 0.2 mm at most conditions (except at v = 43 m/min, f = 0.25 mm/r). Excessive tool flank typically resulted in tool breakage at the cutting edge for uncoated tools. Abrasive and adhesive wear of cutting tools were observed at low cutting speeds while diffusion and chemical wear occurred at higher cutting speeds.     

Integrated environmental assessment of biodiesel production from soybean in Brazil

This paper presents the results of an environmental impact assessment of biodiesel production from soybean in Brazil. In order to achieve this objective, environmental impact indicators provided by Emergy Accounting (EA), Embodied Energy Analysis (EEA) and Material Flow Accounting (MFA) were used. The results showed that for one liter of biodiesel 8.8 kg of topsoil are lost in erosion, besides the cost of 0.2 kg of fertilizers, about 5.2 m² of crop area, 7.33 kg of abiotic materials, 9.0 tons of water and 0.66 kg of air and about 0.86 kg of CO₂ were released. About 0.27 kg of crude oil equivalent is required as inputs to produce one liter of biodiesel, which means an energy return of 2.48 J of biodiesel per Joule of fossil fuel invested. The transformity of biodiesel (3.90E + 05 seJ J^?1) is higher than those calculated for fossil fuels as other biofuels, indicating a higher demand for direct and indirect environmental support. Similarly, the biodiesel emergy yield ratio (1.62) indicates that a very low net emergy is delivered to consumers, compared to alternatives. Obtained results show that when crop production and industrial conversion to fuel are supported by fossil fuels in the form of chemicals, goods, and process energy, the fraction of fuel that can actually be considered renewable is very low (around 31%).     

On wear resistance of tool steel

Maintaining a reasonably low cutting tool wear when producing forming tools is a general challenge in the development of new forming tool materials. The tool life of a hot forming tool steel (H13) has been significantly improved by reducing its Si-content from 1.0 to 0.06 wt.%. However, this modified H13 (MH13) also displays a reduced cutting tool life due to higher cutting forces and a stronger tendency to form built up layers (BUE) on the cutting edge. This paper explains why.Gleeble tests of MH13 revealed a significantly higher flow stress in the 820–900 °C temperature interval in MH13 compared to H13. Thermo-Calc simulations showed that when reducing the Si-content from 1.0 to 0.06 wt.% the initial temperature for ferrite-to-austenite transformation (A1) was reduced from 900 °C to 820 °C. Knowing that austenite has totally different mechanical and thermal properties than ferrite, the difference in A1 between the two steels explains the higher cutting forces and higher tendency for BUE-formation. The conclusion is that the difference in machinability between H13 and MH13 is primarily related to their difference in A1.An attempt was also made to find a new tool material composition that can combine the wear resistance of MH13 and the good machinability of H13. Thermo-Calc simulations were performed with slightly modified alloying content without changing its properties as a good forming tool material, with the aim to increase A1. For instance, reducing the Mn content from 0.5 to 0.05 wt.% proved to increase A1 from 820 to 850 °C.     

Exceedance of modern ‘background’ fine-grained sediment delivery to rivers due to current agricultural land use and uptake of water pollution mitigation options across England and Wales

Excessive loss of fine-grained sediment to rivers is widely recognised as a global environmental problem. To address this issue, policy teams and catchment managers require an estimate of the ‘gap’ requiring remediation, as represented by the excess above ‘background’ losses. Accordingly, recent work has estimated the exceedance of modern ‘background’ sediment delivery to rivers at national scale across England and Wales due to (i) current agricultural land cover, cropping and stocking, and (ii) current land use corrected for the uptake of on-farm mitigation measures. This sectoral focus recognises that, nationally, agriculture has been identified as the principal source of fine sediment loss to the aquatic environment. Two estimates of modern ‘background’ sediment loss, based on paleolimnological evidence, were used in the analysis; the target modern ‘background’ (TMBSDR) and maximum modern ‘background’ (MMBSDR) sediment delivery to rivers. For individual (n = 4485) non-coastal water bodies, the sediment ‘gap’ in excess of TMBSDR and MMBSDR, due to current land cover, cropping and stocking, was estimated to range up to 1368 kg ha⁻¹ yr⁻¹ (median 61 kg ha⁻¹ yr⁻¹) and 1321 kg ha⁻¹ yr⁻¹ (median 19 kg ha⁻¹ yr⁻¹), respectively. The respective ranges in conjunction with current land cover, cropping and stocking but corrected for the potential impact of on-farm sediment mitigation measures were up to 1315 kg ha⁻¹ yr⁻¹ (median 50 kg ha⁻¹ yr⁻¹) and 1269 kg ha⁻¹ yr⁻¹ (median 8 kg ha⁻¹ yr⁻¹). Multiplication of the estimates of excess sediment loss corrected for current measure uptake, above TMBSDR and MMBSDR, with estimated maximum unit damage costs for the detrimental impacts of sediment pollution on ecosystem goods and services, suggested respective water body ranges up to 495 £ ha⁻¹ yr⁻¹ and 478 £ ha⁻¹ yr⁻¹. Nationally, the total loss of sediment in excess of TMBSDR was estimated at 1,389,818 t yr⁻¹ equating to maximum environmental damage costs of £523 M yr⁻¹, due to current structural land use, compared to 1,225,440 t yr⁻¹ equating to maximum damage costs of £462 M yr⁻¹ due the uptake of on-farm sediment control measures. The corresponding total loss of sediment in excess of MMBSDR was estimated at 1,038,764 t yr⁻¹ equating to maximum damage costs of £462 M yr⁻¹, compared with 890,146 t yr⁻¹ and £335 M yr⁻¹ correcting excess agricultural sediment loss for current implementation of abatement measures supported by policy instruments. This work suggests that the current uptake of sediment control measures on farms across England and Wales is delivering limited benefits in terms of reducing loadings to rivers and associated environmental damage costs.     

Potential carbon sequestration in China’s forests

Forests are believed to be a major sink for atmospheric carbon dioxide. There are 158.94 million hectares (Mha) of forests in China, accounting for 16.5% of its land area. These extensive forests may play a vital role in the global carbon (C) cycle as well as making a large contribution to the country’s economic and environmental well-being. Currently there is a trend towards increased development in the forests. Hence, accounting for the role and potential of the forests in the global carbon budget is very important.In this paper, we attempt to estimate the carbon emissions and sequestration by Chinese forests in 1990 and make projections for the following 60 years based on three scenarios, i.e. “baseline”, “trend” and “planning”. A computer model F-CARBON 1.0, which takes into account the different biomass density and growth rates for the forests in different age classes, the life time for biomass oxidation and decomposition, and the change in soil carbon between harvesting and reforestation, was developed by the authors and used to make the calculations and projections. Climate change is not modelled in this exercise.We calculate that forests in China annually accumulate 118.1 Mt C in growth of trees and 18.4 Mt in forest soils, and release 38.9 Mt, resulting in a net sequestration of 97.6 Mt C, corresponding to 16.8% of the national CO₂ emissions in 1990. From 1990 to 2050, soil carbon accumulation was projected to increase slightly while carbon emissions increases by 73, 77 and 84%, and net carbon sequestration increases by −21, 52 and 90% for baseline, trend and planning scenarios, respectively. Carbon sequestration by China’s forests under the planning scenario in 2000, 2010, 2030 and 2050 is approximately 20, 48, 111 and 142% higher than projected by the baseline scenario, and 8, 18, 34 and 26% higher than by the trend scenario, respectively. Over 9 Gt C is projected to accumulate in China’s forests from 1990 to 2050 under the planning scenario, and this is 73 and 23% larger than projected for the baseline and trend scenarios, respectively. During the period 2008–2012, Chinese forests are likely to have a net uptake of 667, 565 and 452 Mt C, respectively, for the planning, trend and baseline scenarios. We conclude that China’s forests have a large potential for carbon sequestration through forest development. Sensitivity analysis showed that the biggest uncertainty in the projection by the F-CARBON model came from the release coefficient of soil carbon between periods after harvesting and before reforestation.     

Conceptual chemical process design in a sustainable technological world

Delft University has an established track record in educating MSc students the art of designing chemical processes and products. To foster its future position an experimental conceptual design program has been set up. In this program sustainability requirements are used to stimulate creativity. Our vision is that (designs of) processes, products and systems should fit in a sustainable technological world (STW). The STW is in balance with the other great cycles on Earth, being the exchange of water between hydrosphere and atmosphere and the exchange of carbon dioxide between atmosphere and biosphere. The STW has, like the biosphere and hydrosphere, a certain upper mass (110 Gton) and energy (8800 GW). The STW itself is evolutionary and cannot be designed, yet its content—technological artifacts—is designed. Newly designed artifacts requiring an average life span of 25 years (one human generation), should fit the STW. The total annual product renewal of the STW is 4.4 Gton/year and the energy consumption 64 MJ/kg. These numbers total both industrial production as well as energy spent by consumers using the artifacts. Conceptual designs of chemical processes should fit in this concept of a STW. This means that processes requiring a high energy level are subject to change, for they limit society's patterns of energy consumption. Chemical processes demanding a lot of chemical energy are reduction processes: primary processes (roasting ores and biomass) and secondary processes (dissociations and dehydrogenations). In this article a conceptual design of both types of processes is presented. The first results show that their energy consumption fits the STW and points towards new design solutions for chemical processes, new applications of chemical products and new relationships with other technological sciences.     

Modeling residual flood risk behind levees,Upper Mississippi River,USA

Flood protection from levees is a mixed blessing, excluding water from the floodplain but creating higher flood levels (“surcharges”) and promoting “residual risk” of flood damages. This study completed 2D hydrodynamic modeling and flood-damage analyses for the 459 km² Sny Island levee system on the Upper Mississippi River. These levees provide large economic benefits, at least $51.1 million per year in prevented damages, the large majority provided to the agricultural sector and a small subset of low-elevation properties. However these benefits simultaneously translate into a large residual risk of flood damage should levees fail or be overtopped; this risk is not recognized either locally in the study area nor in national policy. In addition, the studied levees caused surcharges averaging 1.2–1.5 m and locally as high as 2.4 m, consistent with other sites and studies. The combined hydraulic and economic modeling here documented that levee-related surcharge + the residual risk of levee overtopping or failure can lead to negative benefits, meaning added long-term flood risk. Up to 31% of residential structures in the study area, 8% of agricultural structures, and 22% of commercial structures received negative benefits, totaling $562,500 per year. Although counterintuitive, structures at the margin of a leveed floodplain can incur negative benefits due to greater flood levels resulting from levees purportedly built to protect them. National levee policies and plans for local projects are unbalanced, crediting levee benefits but rarely fully planning for adverse impacts or considering alternatives.     

Water quality management in the lower stretch of the river Ganges,east coast of India: an approach through environmental education

The lower tidal stretch of the river Ganges, known as Hugli (ca. 280 km), flows southward before entering the Bay of Bengal forming a vast mangrove-enriched estuarine delta called Sunderbans. Hugli estuary is a typical example of tide-dominated sink for contaminants from multifarious sources. This major important river is subjected to anthropogenic stress due to the socio-economic importance of these areas based on growth of industry, agriculture, aquaculture, port activities, fishing and tourism. The living resources have been degraded recently due to increases in population pressure, pollution and natural resource consumption to the extent of overexploitation. The present paper critically examines the physicochemical characteristics and level of dissolved heavy metals at three ecologically distinct zones along the course of the river – Babughat located in the eastern part of the metropolitan megacity Calcutta (140 km upstream from seaface), Diamond Harbor (70 km upstream from sea face) and Gangasagar positioned at the mouth of the Ganges estuary.Physicochemical characteristics of this partially mixed estuary are largely influenced by the interaction of seawater and discharge of riverine freshwater, annual precipitation and surface runoff. The levels of salinity, total dissolved solids, hardness and conductivity showed an increasing downward trend. Marked increase in biochemical oxygen demand (BOD) values (2.20–5.95 mg/l) was recorded in Babughat whereas correspondingly low values (0.75–2.82 mg/l) were noticed at Gangasagar. This can be attributed mainly due to huge organic load of untreated sewage from the twin city Howrah and Calcutta situated in the east and west of the river. Spatiotemporal distribution of heavy metals reveals a wide range of variations reflecting input of huge anthropogenic inputs associated with a number of physical and chemical processes. Levels of metals registered a seasonal pattern, with an increase during late monsoon months (September–October), a period characterized by low salinity and relatively low pH of the water. Elevated levels of dissolved Hg and Pb were also recorded in Babughat, with values ranging from 0.16 to 0.95 μg/ml and 0.017 to 0.076 μg/ml, respectively, this high values for Hg can be attributed to the discharge from pulp and paper manufacturing units and to atmospheric input and runoff of automobile emission for Pb.It was revealed that the socio-economic development of Calcutta, the most potential economic zone in India situated on the east bank of Hugli river, has had a significant impact on the water quality of this major river. The deterioration of water quality is directly related to nonfunctioning and malfunctioning of wastewater treatment plants and lack of environmental planning and coordination. To restore the ecological stability and economic vitality of this river, the following measures have been suggested: (i) strong vigilance programme is to be undertaken towards installation and maintenance of the wastewater treatment plants to check the flow of persistent contaminants in the river water and (ii) execution of legislation and mass awareness programmes are to be enacted to restore the sound health of the river. The authors urge that environmental education should be used as an effective tool for water resource management dealing with intricate and complex problems in the interaction between nature, technology and human beings.     

Fostering pollution prevention in small businesses: the Enviroclub initiative

The Enviroclub initiative was developed by three federal government agencies (Canada Economic Development for Quebec Regions, Environment Canada and the National Research Council Canada) to assist small and medium sized enterprises (SMEs) in improving their profitability and competitiveness through enhanced environmental performance. An Enviroclub consists of a group of 10–15 SMEs, each of which carries out one profitable pollution prevention project. To support this practical experience, business participants attend 4 days of workshops on various themes related to environmental performance, spread out over a period of about 6 months. Enviroclubs have been undertaken in several regions of Quebec, and are delivered by not-for-profit organisations, mainly Enviro-Access and the Centre québécois de développement durable. Projects implemented in seven Enviroclubs brought annual savings of CAD$5.1 million and multiple environmental benefits including annual reductions in resource use, such as water (536,000 m³), petroleum products (225,000 litres), wood (11,300 m³) and emissions, such as greenhouse gases (17,100 tonnes equivalent CO₂), hazardous wastes (708 tonnes) and toxic substances (53 tonnes).     

Sustainability assessment of large-scale ethanol production from sugarcane

The present study assesses the sustainability of ethanol produced from sugarcane and examines the environmental feasibility of a large-scale production through the use of: fossil fuel embodied energy and Emergy Assessment including farm and industrial production phases. The study indicates that about 1.82 kg of topsoil eroded, 18.4 l of water and 1.52 m² of land are needed to produce 1 l of ethanol from sugarcane. Also, 0.28 kg of CO₂ is released per liter of ethanol produced. The energy content of ethanol is 8.2 times greater than the fossil-based energy required to produce it. The transformity of ethanol is about the same as those calculated for fossil fuels. The Renewability of ethanol is 30%, a very low value; other emergy indices indicate important environmental impacts as well as natural resources consumption. The results obtained indicate that sugarcane and ethanol production present low renewability when a large-scale system is adopted.