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2003

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Sammendrag

A model is presented to investigate the optimal economic life cycle of grass leys with winter damage problems in northern Norway and to determine the threshold of winter damage before it is profitable to reseed. A two‐level hierarchic Markov process has been constructed using the MLHMP software (the MLHMP software and the plug‐in constructed for this model are available for download at http://www.prodstyr.ihh.kvl.dk/software/mlhmp.html). The model takes uncertainty concerning yield potential, damage estimation and weather‐dependent random fluctuations into account. A Kalman filter technique is used for updating the knowledge of yield potential and damage level. The application of the model is demonstrated using data from two commercial Norwegian farms. As parameter estimates vary considerably among farms, it is concluded that decision support concerning optimal economic life cycle of grass leys should be done at farm level. The results also show the importance of using a flexible dynamic replacement strategy. Use of the model for specific farm situations is illustrated.

Sammendrag

Folk med øye for endringer i naturen kunne vanskelig unngå å oppdage de store fargeforandringene, spesielt på gråorbladenes underside i september-oktober 2002. Bladundersidene ble nesten gullfarget av kraftige angrep av rustsopp. Mindre angrepne blad ble mer brunflekket eller bleikflekket på undersiden. Bladoversidene ble mer blasse og grågrønne enn ikke-angrepne blad. Etter hvert rullet også bladkantene seg inn, så det ble en lett sopp å kjenne igjen fra bilvinduet.

Sammendrag

Summary (English) Pharmaceuticals such as ibuprofen, carbamacepin and naproxen and the endocrine disrupters bisphenol A and nonylphenol are found in leachates from Norwegian municipal landfills. Ibuprofen and the musk compounds tonalid and galaxolide were found in all samples, but the concentration in the old, inactive part of the landfill was particularly high. The endocrine distruptors bisphenol A and nonylphenol were also detected in all samples, and the concentrations in two water samples taken downstream the landfill, were in the same range as found in the old part. The PAHs found in the leachates were methyl substituted naphtahalen, biphenyl, acenapthylene, acenapthene, fluorene and phenanthrene. All samples were filtrated (< 0,5 ?m) before analysis. Filtrates from two wells were analyzed to measure transportable organic pollutants. Most of the PAH compounds were detected both in filtrate of water sample from the new, active part of the landfill and filtrate of influent water to the treatment plant which is located 200 m downstream the landfill. This was also the case for the polycyclic musk compounds and bisphenol A. Nonylphenol was detected only in the filtrate from samples in the new landfill.

Sammendrag

Several biocells varying from 100 m3 to about 8000 tons have been established at waste treatment locations in Norway since 1998. We studied biocells by characterizing the waste material by degradation, gas and leachate emission and post-treatment potential, by taking several samples distributed in space and time. Field sample analyses were water content, leachate temperature, redox conditions, oxygen content, electrical conductivity and pH, and gas temperature, O2, CH4 and CO2 concentrations. Waste samples were drilled up by a 10-inch auger down to 6 m depth. The collected samples were analyzed and used for composting experiments. The temperature in the biocelles varied between 10 to 14 ºC in the period from august to December. The waste was characterised as completely or slightly completely degraded after 4 years of biocell storage/treatment, based on "Rotte-test" and respirometer analyses. Microbial analyses showed that the material was free from salmonella, but contained some thermotolerant colibacteria in the most degraded part. Samples from the slightly degraded waste were also free from thermotolerant colibacteria. None of the waste samples showed any inhibition against the germination of plants. The temperature in the most degraded material did not increase significantly during composting. This material can thus not be treated aerobically after removal from the biocell, ie. for reducing pathogens. The factors leachate strenght measured as electrical conductivity, BOD and C/N-ratio best explained the methane content of the biogas in each sampling point. A total production of 593 t landfill gas has been measured from the large biocell. The annual mean methane concentration increased from 28 to 56%, with an overall mean of 48%. This gives a 21% degradation of organic carbon in four years, based on certain assumptions on the incoming waste. The estimated degradation of organic matter is between 50% and 75% in four years.