Using growth curves to forecast long-term trends for processed raw materials

The methods of using growth curves in the economic field to forecast consumption and market developments have been based on the ‘black box’ principle in most of the published cases and have therefore failed to produce reliable results in the medium and long term. This paper introduces an engineering approach for forecasting long-term trends pertaining to the use of processed raw materials. The forecasting is performed by means of a newly developed growth model. To prove the usefulness and validity of the model presented, long-term trends have been calculated for various processed raw materials, such as nickel, platinum and steel.     

Controlled-release system for the insect growth regulator cyromazine

An encapsulation system designed to give long-lasting effectiveness of the insect growth regulator (IGR) cyromazine (Neporex) against Culex pipiens (Culicidae) mosquito larvae was developed. The main thrust of the research was to develop a simple method for preparing controlled-release formulations by means of an extrusion technique in combination with a supplementary coating and to study the release characteristics and effectiveness of the formulations. A series of formulations were prepared with low-density polyethylene (LDPE 600) for the matrix and with polyurea or one of four types of polyurethane for the coating. The rate of release of the active material from the controlled-release formulations was determined in an in vitro dissolution system. The biological activity of the controlled-release formulations was tested in vivo against C. pipiens larvae.     

Environmental impact studies: An interdisciplinary approach for assigning priorities

The cross-impact assessment process (CAP) is presented as a practical method for efficiently identifying a parsimonious set of critically important variables and associated relationships needed to conduct environmental impact studies. CAP was developed from the logic of a number of techniques that are collectively referred to as cross-impact analysis. The process is based on a series of structured workshops. The participants represent a variety of disciplines and individual members are selected because they have both the depth of understanding necessary to contribute specific knowledge on the environmental impact assessment problem and the breadth of view to integrate that knowledge with the information provided by other panelists. The results of the workshops are summarized in an importance index and presented in a cross-impact matrix. CAP is illustrated with an example from an Upper Mississippi River recreation impact study, but it can also be applied to any environmental impact assessment problem that can be characterized as a system of variables and relationships. CAP also provides an efficient and reasonably objective means for assigning priorities to environmental impact studies.     

An analytical framework for strategic delta planning: negotiating consent for long-term sustainable delta development

Sectoral planning on water, agriculture and urban development has not been able to prevent increased flood risks and environmental degradation in many deltas. Governments conceive strategic delta planning as a promising planning approach and develop strategic delta plans. Such plans are linked to actions and means for implementation in the short-term, in line with long-term strategic choices. This paper introduces an analytical framework that focuses on the role of actors, innovative solutions and participatory planning tools in negotiating consent for the strategic choices in a delta plan and its implementation. Cases of Bangladesh, the Netherlands and Vietnam are discussed as a plausibility probe to explore the framework's potential. The probe reveals that the framework is promising to explain the process and outcomes of strategic delta planning in urbanizing deltas. The paper ends with an initial research agenda to stimulate research and discussion on this new delta planning approach.     

An erosion-based land classification system for military installations

The universal soil loss equation (USLE) has been integrated with a geographic information system known as the geographical resources analysis support system (GRASS) to create a land classification system for use by military trainers and land managers to minimize the environmental impacts of military training activities. The USLE provides an estimate of current average annual sheet and rill erosion based upon factors representing climate, soil erodibility, topography, cover, and conservation support practices. The erosion estimate is compared to erosion tolerance values to produce an expression of the current erosion status. An index of inherent site erodibility is also achieved through manipulation of the USLE. Based on published soil surveys, satellite imagery, and ground-truth vegetation transects, data layers are created within GRASS for each of the component factors of the USLE. Appropriate mathematical operations are performed with the data layers, and color-coded maps are produced that represent the erosion status and erodibility index for each 50-m × 50-m area of soil surface. These maps aid military trainers and land managers in scheduling appropriate kinds and intensities of military training activities.     

An interval-based regret-analysis method for identifying long-term municipal solid waste management policy under uncertainty

In this study, an interval-based regret-analysis (IBRA) model is developed for supporting long-term planning of municipal solid waste (MSW) management activities in the City of Changchun, the capital of Jilin Province, China. The developed IBRA model incorporates approaches of interval–parameter programming (IPP) and minimax–regret (MMR) analysis within an integer programming framework, such that uncertainties expressed as both interval values and random variables can be reflected. The IBRA can account for economic consequences under all possible scenarios associated with different system costs and risk levels without making assumptions on probabilistic distributions for random variables. A regret matrix with interval elements is generated based on a matrix of interval system costs, such that desired decision alternatives can be identified according to the interval minimax regret (IMMR) criterion. The results indicate that reasonable solutions have been generated. They can help decision makers identify the desired alternatives regarding long-term MSW management with a compromise between minimized system cost and minimized system-failure risk.     

Performance of an overland flow system for advanced treatment of wastewater plant effluent

Overland flow (OF) systems were evaluated and compared for advanced treatment of municipal and industrial effluents, including nutrients and nondegradable chemical oxygen demand (COD) removal. Three pilot plants were constructed at the Shahin Shahr Wastewater Treatment Plant (WWTP), Isfahan, Iran. Each pilot was assigned a specific wastewater and all were simultaneously operated for 8 months. Treatment of primary effluent, activated sludge secondary effluent, and lagoon effluent of textile wastewater was investigated at application rates (ARs) of 0.15, 0.25, and 0.35m(3)m(-1)h(-1). During 5 months of stable operation after a 3-month acclimation period, mean removals of total 5-day biochemical oxygen demand (TBOD(5)), total COD (TCOD), total suspended solids (TSS), total nitrogen (TN), total phosphorus (TP) and turbidity were 74.5%, 54.8%, 66.2%, 39.4%, 35.8%, and 67.7% for primary effluent; 52.9%, 52.9%, 66.5%, 44.4%, 39.8%, and 50.1% for activated sludge effluent; 65.7%, 58.7%, 70.3%, 41.7%, 41.3%, and 54.9% for textile wastewater lagoon effluent, respectively. The model of Smith and Schroeder, 1985. Field studies of the overland flow process for the treatment of raw and primary treated municipal wastewater. Journal of Water Pollution Control Federation 57, 785-794] was satisfactory for TBOD(5). For all treatment parameters a standard first-order removal model was inadequate to represent the data but a modified first-order model provided a satisfactory fit to the data. Based on the results of this study, it can be concluded that an OF system as advanced treatment had the ability to meet effluent discharge permit limits and was an economical replacement for stabilization ponds and mechanical treatment options.     

Influence of plant growth on degradation of linear alkylbenzene sulfonate in sludge-amended soil

Widespread application of sewage sludge to agricultural soils in Denmark has led to concern about the possible accumulation and effects of linear alkylbenzene sulfonate (LAS) in the soil ecosystem. Therefore, we have studied the uptake and degradation of LAS in greenhouse pot experiments. Sewage sludge was incorporated into a sandy soil to give a range from very low to very high applications (0.4 to 90 Mg dry wt. ha(-1)). In addition, LAS was added as water solutions. The soil was transferred to pots and sown with barley (Hordeum vulgare L. cv. Apex), rape (Brassica napus L. cv. Hyola 401), or carrot (Daucus carota L.). Also, plant-free controls were established. For all additions there was no plant uptake above the detection limit at 0.5 mg LAS kg(-1) d.w, but plant growth stimulated the degradation. With a growth period of 30 d, LAS concentrations in soil from pots with rape had dropped from 27 to 1.4 mg kg(-1) dry wt., but in plant-free pots the concentration decreased only to 2.4 mg kg(-1) dry wt. When LAS was added as a spike, the final concentration in soil from planted pots was 0.7 mg kg(-1) dry wt., but in pots without plants the final concentration was much higher (2.5 mg kg(-1) dry wt.). During degradation, the relative fraction of homologues C10, C11, and C12 decreased, while C13 increased.     

Impact of using paper mill sludge for surface-mine reclamation on runoff water quality and plant growth

Paper mills generate large amounts of solid waste consisting of fibrous cellulose, clay, and lime. Paper mill sludge (PMS) can improve reclamation of surface-coal mines where low pH and organic-carbon levels in the spoil cover material can inhibit revegetation. When applied at high rates, however, PMS may adversely impact the quality of surface runoff. Therefore, we applied PMS at 0, 224, and 672 dry Mg ha(-)(1) to 22.1 x 4.6-m plots at a recently mined site and monitored runoff for a total of 13 mo. The zero-rate plots served as controls and received standard reclamation consisting of mulching with hay and fertilization at planting. Compared to the control plots, PMS reduced runoff fourfold to sixfold and decreased erosion from 47 Mg ha(-1) to <1 Mg ha(-1). Most of the reduction occurred in the 2.5 mo before the plots were planted. Flow-weighted average dissolved oxygen concentrations in runoff from plots at the 224 and 672 Mg ha(-1) rates, however, were much lower (相似文献   

Denitrification at a long-term forested land treatment system in the Piedmont of Georgia

Spray irrigation of forested land can provide an effective system for nutrient removal and treatment of municipal wastewater. Evolution of N2 + N2O from denitrifying activity is an important renovation pathway for N applied to forested land treatment systems. Federal and state guidance documents for design of forested land treatment systems indicate the expected range for denitrification to be up to 25% of applied N, and most forest land treatment systems are designed using values from 15 to 20% of applied N. However, few measurements of denitrification following long-term wastewater applications at forested land treatment sites exist. In this study, soil N2 + N2O-N evolution was directly measured at four different landscape positions (hilltop, midslope, toe-slope, and riparian zone) in a forested land treatment facility in the Georgia Piedmont that has been operating for more than 13 yr. Denitrification rates within effluent-irrigated areas were significantly greater than rates in adjacent nonirrigated buffer zones. Rates of N2 + N2O-N evolved from soil in irrigated forests ranged from 5 to 10 kg ha(-1) yr(-1) N on the three upland landscape positions and averaged 38 kg ha(-1) yr(-1) N within the riparian zone. The relationship between measured riparian zone denitrification rates and soil physical and chemical properties was poor. The best relationship was with soil temperature, with an r2 of 0.18. Overall, on a landscape position weighted basis, only 2.4% of the wastewater-applied N was lost through denitrification.     

An approach to tree thinning to structure southern African savannas for long-term restoration from bush encroachment

Due to bush encroachment the grazing capacity of large areas of the southern African savanna has declined, often to such an extent that many previously economic livestock properties are now no longer economically viable. Attempts at restoring encroached areas by the removal of some or all of the woody plants will normally result in an increase of grass production and thus also the grazing capacity. However, the results of woody plant removal may differ between vegetation types, with the outcome determined by both negative and positive responses to tree removal. The rapid establishment of tree seedlings after the removal of some or all of the mature woody plants may reduce the effective time span of restoration measures. In many cases the resultant re-establishment of new woody seedlings may in time develop into a state that is worse than the original state. This paper is an attempt to summarize existing knowledge on the importance of woody plants in savanna and explore measures, based on ecosystem dynamics, which can be utilized to restore encroached areas more successfully. It is hypothesized that a more stable environment can be created by maintaining or restoring savanna structure (large trees). In a structured savanna, large trees are able to suppress the establishment of new seedlings, while maintaining the other benefits of woody plants like soil enrichment and the provision of food to browsing herbivore species. Effective restoration of encroached areas should not be considered a once-off event, but rather a long-term commitment.     

Voluntary environmental management system standards: Case studies in implementation

Many anticipate that over the next decade, voluntary environmental management system (EMS) standards will take on the same importance in the marketplace as the ISO 9000 quality standards; the draft international EMS standard (ISO 14001) is on pace to be completed by mid-1996. In the United States, despite rapidly growing interest in EMS standards, most companies and regulatory agencies are uncertain about their potential benefits and about the process of developing an EMS. Case studies of EMS implementation, particularly in small and medium-sized companies, are needed to demonstrate the process and identify areas in which further EMS guidance is needed for environmental managers. This article presents seven case studies of EMS implementation in small, medium-sized, and large companies. Each company is participating in an EPA-sponsored Demonstration Project in which a variety of organizations are piloting the implementation of EMS standards (the project is being coordinated by NSF International, a not-for-profit company specializing in environmental and public health standards and certification). The case studies, written by the companies themselves, share experiences of EMS assessment, planning, and implementation, and discuss challenges that are special to particular industries.     

Effect of culture time on the growth curve and power performance in a microbial fuel cell at a fixed amount of liquid culture

The microbial fuel cell uses the microorganism biochemistry to carry on the energy conversion. Concerning the experimental precision, the colony culture would be replaced by a fixed amount of liquid culture for Microbial fuel cell of Escherichia coli. The anode and cathode chambers whose each volume is 100 mL were utilized, the effective surface area of proton exchange membrane Nafion-117 is about 9 cm². In addition, the electrode area of carbon cloth is 20 cm². Three kinds of Escherichia coli, named as BCRC No. 10322, 10675 and 51534, respectively, would be selected. Results show that the electricity performance of Escherichia coli of BCRC No.51534 is better than the other microorganism studied because of having a larger open circuit voltage of 1.01 V and limiting current 22 mA, the maximum power density of 1342 mW/m^2, and average working power density of 295 mW/m² would be produced. These results would be useful to improve the performance of microbial fuel cell.     

Use of commercial plant species in a hydroponic system to treat domestic wastewaters

The objectives in this work were to investigate a conceptual layout for an inexpensive and simple system that would treat primary municipal wastewater to discharge standards. A commercial hydroponic system was adapted for this study and the wastewater was used to irrigate wooly digitalis (Digitalis lanata Ehrh.) and foxglove (Digitalis purpurea L.). These plants are medicinal and produce cardenolide compounds. Influent and effluent samples were collected once a month for six months and analyzed to determine the various parameters relating to water quality. The legal discharge levels for total suspended solids (SS), biochemical oxygen demand (BOD5), and chemical oxygen demand (COD) were reached for the two tested plants after 48 h of wastewater treatment; the removal was 82, 93, and 79%, respectively, for wooly digitalis and 92, 92, and 84%, respectively, for foxglove. Similar results were obtained during a 6-mo period although the sewage composition varied widely. The system tended to be unable to remove N and P to concentrations below regulated levels. Compared with the nutrient solution composition, the wastewater was more concentrated in Na+ and Cl- and less in N, K+, and Ca2+. These variations can lead to the decline of wooly digitalis plants. Foxglove developed a significant root system to increase mineral absorption wastewater being used as the unique nutritive source. After 10 wk all the wooly digitalis seedlings were dead. Despite this fact, however, the root system remained in place for a significant time (< 4 mo), thus continuing to filter wastewater and to be used as a bacterial support thus making it possible to have a security period to replace the dead plants.     

An integrated assessment of long-term changes in the hydrology of three lowland rivers in eastern England

The flow records of the Rivers Bure, Nar and Wensum in eastern England have been examined with the aim of identifying long-term changes in flow behaviour relating to variations in rainfall amount, land use, land drainage intensity and water resources use. In the study area, and since 1931, there is no evidence of long-term change in rainfall amount or distribution, on either an annual or seasonal basis. Despite changes in water resources use and catchment characteristics since the beginning of the century, such as the ending of water milling and increased land drainage and arable farming, rainfall-runoff modelling over the period 1964-1992 showed that the relationship between rainfall and runoff has remained essentially unchanged in the three study rivers. A catchment resource model used to 'naturalise' the historic flow records for the period 1971-1992 to account for the net effect of water supply abstractions and discharges revealed that mean river flows have been altered by surface water and groundwater abstractions, although the average losses to mean weekly flows due to net abstractions for all water uses was no greater than 3%. Greater losses occurred during drought periods as a result of increased consumptive use of water for spray irrigation and amounted to a maximum loss of 24% in the Nar catchment. In lowland areas such as eastern England that are prone to summer dry weather and periodic drought conditions, an integrated approach to river basin management, as advocated by the EU Framework Directive, is recommended for future management of surface and groundwater resources for public water supplies, river regulation purposes and industrial and agricultural demands.     

An environmental sustainability based budget allocation system for regional water quality management

A budget allocation system for regional water quality management to achieve environmental sustainability was developed in this study to assist a local authority with making appropriate budget allocations for improving Regional Water Environmental Sustainability (RWES) in an efficient manner. The system consists of visions and goals, RWES indicators, and an analysis of budget allocation versus RWES. Visions and goals define task priorities for improving water environmental sustainability. Indicators are used to measure the progress of related tasks toward RWES goals. These indicators are classified by the Driving Force-State-Response (DSR) framework to facilitate the analysis of relationships among indicators. Linkages between budget allocation and indicators are also analyzed, and the result is used to assess whether the available budget is allocated properly to raise the RWES. The applicability of the system is demonstrated by a case study involving a local environmental protection authority.     

Inoculation of plant growth promoting bacterium Achromobacter xylosoxidans strain Ax10 for the improvement of copper phytoextraction by Brassica juncea

In this study, a copper-resistant plant growth promoting bacterial (PGPB) strain Ax10 was isolated from a Cu mine soil to assess its plant growth promotion and copper uptake in Brassica juncea. The strain Ax10 tolerated concentrations up to 600 mg CuL(-1) on a Luria-Bertani (LB) agar medium and utilized 1-aminocyclopropane-1-carboxylic acid (ACC) as a sole N source in DF salts minimal medium. The strain Ax10 was characterized as Achromobacter xylosoxidans based on its 16S rDNA sequence homology (99%). The bacterium A. xylosoxidans Ax10 has also exhibited the capability of producing indole acetic acid (IAA) (6.4 microg mL(-1)), and solubilizing inorganic phosphate (89.6 microg mL(-1)) in specific culture media. In pot experiments, inoculation of A. xylosoxidans Ax10 significantly increased the root length, shoot length, fresh weight and dry weight of B. juncea plants compared to the control. This effect can be attributed to the utilization of ACC, production of IAA and solubilization of phosphate. Furthermore, A. xylosoxidans Ax10 inoculation significantly improved Cu uptake by B. juncea. Owing to its wide action spectrum, the Cu-resistant A. xylosoxidans Ax10 could serve as an effective metal sequestering and growth promoting bioinoculant for plants in Cu-stressed soil. The present study has provided a new insight into the phytoremediation of Cu-contaminated soil.     

An Analytic Network Process approach for siting a municipal solid waste plant in the Metropolitan Area of Valencia (Spain)

In this paper the Analytic Network Process (ANP) is applied to select the best location for the construction of a municipal solid waste (MSW) plant in the Metropolitan area of Valencia (Spain). Selection of the appropriate MSW facility location can be viewed as a complex multicriteria decision-making problem that requires an extensive evaluation process of the potential MSW plant locations and other factors as diverse as economic, technical, legal, social or environmental issues. The decision-making process includes the identification of six candidate MSW plant sites and 21 criteria grouped into clusters for the construction of a network. Two technicians of the Metropolitan Waste Disposal Agency acted as decision makers (DMs).The influences between the elements of the network were identified and analyzed using the ANP multicriteria decision method. Two different ANP models were used: one hierarchy model (that considers AHP as a particular case of ANP) and another network-based model. The results obtained in each model were compared and analyzed. The strengths and weaknesses of ANP as a multicriteria decision analysis tool are also described in the paper. The main findings of this research have proved that ANP is a useful tool to help technicians to make their decision process traceable and reliable. Moreover, this approach helps DMs undertake a sound reflection of the siting problem.     

An imprecise fuzzy risk approach for water quality management of a river system

Uncertainty plays an important role in water quality management problems. The major sources of uncertainty in a water quality management problem are the random nature of hydrologic variables and imprecision (fuzziness) associated with goals of the dischargers and pollution control agencies (PCA). Many Waste Load Allocation (WLA) problems are solved by considering these two sources of uncertainty. Apart from randomness and fuzziness, missing data in the time series of a hydrologic variable may result in additional uncertainty due to partial ignorance. These uncertainties render the input parameters as imprecise parameters in water quality decision making. In this paper an Imprecise Fuzzy Waste Load Allocation Model (IFWLAM) is developed for water quality management of a river system subject to uncertainty arising from partial ignorance. In a WLA problem, both randomness and imprecision can be addressed simultaneously by fuzzy risk of low water quality. A methodology is developed for the computation of imprecise fuzzy risk of low water quality, when the parameters are characterized by uncertainty due to partial ignorance. A Monte-Carlo simulation is performed to evaluate the imprecise fuzzy risk of low water quality by considering the input variables as imprecise. Fuzzy multiobjective optimization is used to formulate the multiobjective model. The model developed is based on a fuzzy multiobjective optimization problem with max–min as the operator. This usually does not result in a unique solution but gives multiple solutions. Two optimization models are developed to capture all the decision alternatives or multiple solutions. The objective of the two optimization models is to obtain a range of fractional removal levels for the dischargers, such that the resultant fuzzy risk will be within acceptable limits. Specification of a range for fractional removal levels enhances flexibility in decision making. The methodology is demonstrated with a case study of the Tunga–Bhadra river system in India.