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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2006

Abstract

In the traditional EIA procedure environmental vulnerability is only considered to a minor extent in the early stages when project alternatives are worked out. In Norway, an alternative approach to EIA, an integrated vulnerability model (IVM), emphasising environmental vulnerability and alternatives development in the early stages of EIA, has been tried out in a few pilot cases. This paper examines the content and use of the vulnerability concept in the IVM approach, and discusses the concept in an EIA context. The vulnerability concept is best suited to overview analyses and large scale spatial considerations. The concept is particularly useful in the early stages of EIA when alternatives are designed and screened. By introducing analyses of environmental vulnerability at the start of the EIA process, the environment can be a more decisive issue for the creation of project alternatives as well as improving the basis for scoping. Vulnerability and value aspects should be considered as separate dimensions. There is a need to operate with a specification between general and specific vulnerability. The concept of environmental vulnerability has proven useful in a wide range of disciplines. Different disciplines have different lengths of experience regarding vulnerability. In disciplines such as landscape planning and hydrogeology we find elements suitable as cornerstones in the further development of an interdisciplinary methodology. Further development of vulnerability criteria in different disciplines and increased public involvement in the early stages of EIA are recommended.

Abstract

A new compact wastewater treatment system for use in single houses has been constructed in eastern Norway. The system is based on the principles of sub-surface flow constructed wetlands using various types of Filtralite as filter media. It consists of a septic tank followed by an aerobic biofilter succeeded by an upflow saturated filter. The aerobic biofilter is essential to remove organic matter and achieve nitrification, while the upflow filter polishes the wastewater and removes microorganisms and phosphorus. During the first 3 years of operation, the system has show stable and high removal with the following average values measured from the outlet of septic tank to the outlet of the upflow filter: 97.0%-BOD7, 30%-N, 99.4%-P, and 70.8%-SS. No Escherichia coli or somatic coliphages have been detected in the effluent. Due to considerable removal of organic mater, nutrients, and pathogens, the effluent will not negatively affect water and soil ecosystems. The system requires low maintenance and is designed to remove phosphorus for 5 years before renewal of the upflow filter media. When saturated with phosphorus, the media is a suitable fertilizer for plant production. (c) 2006 Elsevier B.V. All rights reserved.

2005

To document

Abstract

In 1991, the first subsurface flow constructed wetland for treatment of domestic wastewater was built in Norway Today, this method is rapidly becoming a popular method for wastewater treatment in rural Norway. This is due to excellent performance even during winter and low maintenance. The systems can be constructed regardless of site conditions. The Norwegian concept for small constructed wetlands is based on the use of a septic tank followed by an aerobic vertical down-flow biofilter succeeded by a subsurface horizontal-flow constructed wetland. The aerobic biofilter, prior to the subsurface flow stage, is essential to remove BOD and achieve nitrification in a climate where the plants are dormant during the cold season. When designed according to present guidelines a consistent P-removal of > 90% can be expected for 15 years using natural iron or calcium rich sand or a new manufactured lightweight aggregate with P-sorption capacities, which exceeds most natural media. When the media is saturated with P it can be used as soil conditioner and P-fertilizer. Nitrogen removal in the range of 40-60% is achieved. Removal of indicator bacteria is high and < 1000 thermotolerant coliforms/100 ml is normally achieved. In 1991, the first subsurface flow constructed wetland for treatment of domestic wastewater was built in Norway. Today, this method is rapidly becoming a popular method for wastewater treatment in rural Norway. This is due to excellent performance evenduring winter and low maintenance. The systems can be constructed regardless of site conditions. The Norwegian concept for small constructed wetlands is based on the use of a septic tank followed by an aerobic vertical down-flow biofilter succeeded by asubsurface horizontal-flow constructed wetland. The aerobic biofilter, prior to the subsurface flow stage, is essential to remove BOD and achieve nitrification in a climate where the plants are dormant during the cold season. When designed according topresent guidelines a consistent P-removal of > 90% can be expected for 15 years using natural iron or calcium rich sand or a new manufactured lightweight aggregate with P-sorption capacities, which exceeds most natural media. When the media is saturated with P it can be used as soil conditioner and P-fertilizer. Nitrogen removal in the range of 40–60% is achieved. Removal of indicator bacteria is high and < 1000 thermotolerant coliforms/100 ml is normally achieved.