OPTIMUM ALTERNATIVES FOR CONTROLLING COMBINED SEWAGE OVERFLOWS - A CASE STUDY1

ABSTRACT: Frequent high quantity overflows of combined sewage entering the Mississippi River near the city of Red Wing, Minnesota, have degraded water quality and caused concern among federal and state environmental agencies. The city of Red Wing was required to conduct a comprehensive waste control study, as part of the sewer system Construction Grant (Section 201 of PL 92–500), to identify alternative waste control and treatment measures and to recommend the optimum combination of alternatives in terms of both cost and waste control effectiveness. The study involved these basic steps: determination of present and future (year 2020) sanitary flow rates and volumes, storm runoff discharges, frequencies and volumes, and combined sewage bypass volumes; identification of alternative waste control measures; elimination of unfeasible alternatives; detailed analysis of the hydrologic, economic, and waste control feasibility of the promising alternatives; selection of the optimum combination of alternative waste control measures to satisfy the study objectives, and determination of construction priorities for the optimum control measures. Because of an uncertain budget and undetermined conditions of state and federal assistance, the city has not yet selected the optimum waste control measure for its needs. When the decisionmaking process between representatives of the city and the state commences, the optimum combination of waste control alternatives can be easily identified using the results of this study.     

Importance of public relations in recycling strategies: principles and case studies

The separate collection of waste, and especially of recyclables with specific collection systems, would not be possible without the involvement of the users. Apart from the physical installations such as collection containers, collection points, etc., the motivation of the users is an essential component. Motivation can be reinforced through public relations work. In addition to the underlying technical considerations, this paper describes the difference between communication in general and public relations and specifically examines public involvement in recycling. Through the use of examples, we look at the targeted users and typical media employed. Furthermore, we analyzes the development of public involvement. The examples show that public relations for recycling strategies relies to a great extent on attitudes, habits, and access to the target group. Thus, standardized procedures cannot be developed. For these reasons, public relation activities must be planned carefully and professionally and include an analysis of the target group, choice of media, and verification of success.     

Assessing Potential for Recovery of Biotic Richness and Indicator Species due to Changes in Acidic Deposition and Lake ph in Five Areas of Southeastern Canada

Biological damage to sensitive aquatic ecosystems is among the most recognisable, deleterious effects of acidic deposition. We compiled a large spatial database of over 2000 waterbodies across southeastern Canada from various federal, provincial and academic sources. Data for zooplankton, fish, macroinvertebrate (benthos) and loon species richness and occurrence were used to construct statistical models for lakes with varying pH, dissolved organic carbon content and lake size. pH changes, as described and predicted using the Integrated Assessment Model (Lam et al., 1998; Jeffries et al., 2000), were based on the range of emission reductions set forth in the Canada/US Air Quality Agreement (AQA). The scenarios tested include 1983, 1990, 1994 and 2010 sulphate deposition levels. Biotic models were developed for five regions in southeastern Canada (Algoma, Muskoka, and Sudbury, Ontario, southcentral Québec, and Kejimkujik, Nova Scotia) using regression tree, multiple linear regression and logistic regression analyses to make predictions about recovery after emission reductions. The analyses produced different indicator species in different regions, although some species showed consistent trends across regions. Generally, the greatest predicted recovery occurred during the final phase of emission reductions between 1994 and 2010 across all taxonomic groups and regions. The Ontario regions, on average, were predicted to recover to a greater extent than either southcentral Québec or the Kejimkujik area of Nova Scotia. Our results reconfirm that pH 5.5–6.0 is an important threshold below which damage to aquatic biota will remain a major local and regional environmental problem. This damage to biodiversity across trophic levels will persist well into the future if no further reductions in sulphate deposition are implemented.     

Social network ties predict land use diversity and land use change: a case study in Ghana

Regional Environmental Change - While it is well documented that informal social ties play a role in information exchange on land management practices, the structural features of such networks that...     

From site-level to regional adaptation planning for tropical commodities: cocoa in West Africa

The production of tropical agricultural commodities, such as cocoa (Theobroma cacao) and coffee (Coffea spp.), the countries and communities engaged in it, and the industries dependent on these commodities, are vulnerable to climate change. This is especially so where a large percentage of the global supply is grown in a single geographical region. Fortunately, there is often considerable spatial heterogeneity in the vulnerability to climate change within affected regions, implying that local production losses could be compensated through intensification and expansion of production elsewhere. However, this requires that site-level actions are integrated into a regional approach to climate change adaptation. We discuss here such a regional approach for cocoa in West Africa, where 70 % of global cocoa supply originates. On the basis of a statistical model of relative climatic suitability calibrated on West African cocoa farming areas and average climate projections for the 2030s and 2050s of, respectively, 15 and 19 Global Circulation Models, we divide the region into three adaptation zones: (i) a little affected zone permitting intensification and/or expansion of cocoa farming; (ii) a moderately affected zone requiring diversification and agronomic adjustments of farming practices; and (iii) a severely affected zone with need for progressive crop change. We argue that for tropical agricultural commodities, larger-scale adaptation planning that attempts to balance production trends across countries and regions could help reduce negative impacts of climate change on regional economies and global commodity supplies, despite the institutional challenges that this integration may pose.     

Assessment of Mexico��s program to use ethanol as transportation fuel: impact of 6% ethanol-blended fuel on emissions of light-duty gasoline vehicles

Recently, the Mexican government launched a national program encouraging the blending of renewable fuels in engine fuel. To aid the assessment of the environmental consequences of this move, the effect of gasoline fuel additives, ethanol and methyl tert-butyl ether, on the tailpipe and the evaporative emissions of Mexico sold cars was investigated. Regulated exhaust and evaporative emissions, such as carbon monoxide, non-methane hydrocarbons, and nitrogen oxides, and 15 unregulated emissions were measured under various conditions on a set of 2005?C2008 model light-duty vehicles selected based on sales statistics for the Mexico City metropolitan area provided by car manufacturers. The selected car brands are also frequent in Canada, the USA, and other parts of the world. This paper provides details and results of the experiment that are essential for evaluation of changes in the emission inventory, originating in the low-blend ethanol addition in light vehicle fuel.     

Human factors applied to alarm panel modernization of nuclear control room

Human factors deal with issues related to humans, their behavior and the physical aspect of the environment in which they work. A control room is a complex system where operators perform plant operation using control systems and carry out monitoring and administrative responsibilities. For safe operation of industrial installation, the performance of the control room crew plays an important role. In this respect, a well designed control room is crucial for safe and efficient operation. The aim of this paper is to propose a methodological framework applied to nuclear control room evaluation, through participatory ergonomics, using operator activity analysis and human factors questionnaire as aid tools. We describe a case study in which the methodology framework was used in the evaluation process of a nuclear control room. The information gathered made possible a series of recommendation for the adequacy of the control room design, assisting in the safety assessment of the nuclear plant operation and justifying the alarm panel modernization.     

The value of information in resource exploration: The interaction of strategic plays and institutional rules

Several characteristics of information used in resource exploration have led to conjectures that the private market will provide a suboptimal amount of such information. A public information provision has been proposed as a remedy, both for problems of underproduction and overproduction of private information. This paper demonstrates that, barring exceptional conditions, public provision of information cannot be guaranteed to be a generic solution to the private information overprovision problem. In fact, an example is developed to demonstrate the possibility that public information exacerbates the private overprovision problem.