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- Alexandersson, Tomas, et al.
(författare)
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Treatment of packaging board whitewater in anaerobic/aerobic biokidney
- 2005
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Ingår i: Water Science and Technology. - 0273-1223. ; 52:10-11, s. 289-298
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Tidskriftsartikel (refereegranskat)abstract
- Whitewater from production of packaging board was treated in a combined anaerobic/aerobic biokidney, both in laboratory scale and pilot plant experiments. Both the laboratory experiments and the pilot plant trial demonstrate that a combined anaerobic/aerobic process is suitable for treating whitewater from a packaging mill. It is also possible to operate the process at the prevailing whitewater temperature. In the laboratory under mesophilic conditions the maximal organic load was 12 kg COD/m(3)*d on the anaerobic reactor and 6.7 kg COD/m(3)*d on the aerobic reactor. This gave a hydraulic retention time, HRT, in the anaerobic reactor of 10 hours and 2 hours in the aerobic reactor. The reduction of COD was between 85 and 90% after the first stage and the total reduction was between 88 to 93%. Under thermophilic conditions in the laboratory the organic load was slightly lower than 9.6 COD/m(3)*d and between 10 and 16 COD/m(3)*d, respectively. The HRT was 16.5 and 3.4 hours and the removal was around 75% after the co anaerobic reactor and 87% after the total process. For the pilot plant experiment at a mill the HRT in the anaerobic step varied between 3 and 17 hours and the corresponding organic load between 4 and 44 kg COD/m(3)*d. The HRT in the aerobic step varied between 1 and 6 hours and the organic load between 1.5 and 26 kg COD/m(3)*d. The removal of soluble organic matter was 78% in the anaerobic step and 86% after the combined treatment at the lowest loading level. The removal efficiency at the highest loading level was about 65% in the anaerobic step and 77% after the aerobic step. In the pilot plant trial the removal efficiency was not markedly affected by the variations in whitewater composition that were caused b y change of production. The variations, however, made the manual control of the nutrient dosage inadequate co and resulted in large variations in effluent nutrient concentration. This demonstrates the need for an automatic nutrient dosage system. The first step towards such a system was to evaluate two different on-line instruments. Both had severe stability problems, which made them unsuitable as parts in a system for control of the nutrient dosage.
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- Björklund, Karin, 1979, et al.
(författare)
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Phthalates and nonylphenols in urban runoff: Occurrence, distribution and area emission factors
- 2009
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 407:16, s. 4665-4672
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Tidskriftsartikel (refereegranskat)abstract
- The urban water system is believed to be an important sink for the nonpoint-source pollutants nonylphenols and phthalates. The presence of nonylphenols (NPs), nonylphenol ethoxylates (NPEOs), and eight phthalates was analyzed in urban stormwater and sediment from three catchment areas in Sweden. Emission loads for these substances were then calculated for a specific urban catchment area. In addition, substance distribution in road runoff passing through a sedimentation facility was modeled using a modified QWASI-model for chemical fate. High concentrations of DEHP, DIDP and DINP (≤ 48, 66 and 200 µg/g dw, respectively) as well as nonylphenol mono- and di-ethoxylate (6.6 and 20 µg/g dw, respectively) were found in the sediment. Aqueous concentrations of the pollutants varied considerably; branched NP was detected in concentrations up to 1.2 µg/L, whereas di(2-ethylhexyl) phthalate (DEHP), diisodecyl phthalate (DIDP), and diisononyl phthalate (DINP) were the most frequently detected phthalates in concentrations up to 5.0, 17 and 85 µg/L, respectively. The fate modeling demonstrated that predicted substance levels in water agreed well with measured levels, whereas the modeled sediment levels were underestimated. Calculation of catchment area emission factors from an urban highway environment revealed that as much as 2.1 kg of total phthalates and 200 g of NP and NPEOs may be emitted per hectare and year. The results indicate that all monitored phthalates, branched NPs and lower NPEOs are present in Swedish urban water systems. The long-chain phthalates DIDP and DINP are believed to occur at higher concentrations than other phthalates because of their higher environmental persistence and their increasing use in Sweden.
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- Jonsson, A., et al.
(författare)
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Evaluation of antidecubitus mattresses
- 2005
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Ingår i: Medical and Biological Engineering and Computing. - 0140-0118 .- 1741-0444. ; 43:5, s. 541-547
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Forskningsöversikt (refereegranskat)abstract
- Pressure sores are a current problem in hospitals and care of the elderly, leading to protracted hospital stays and a high care burden. The trauma for the patients is severe, and the cost of pressure sore prevention and treatment, is considerable. Antidecubitus mattresses are used for prevention and in treatment, but they also contribute to the cost of treating pressure sores. The problem highlighted in the review is that the mattresses' effectiveness in preventing and treating pressure sores has not been sufficiently evaluated. When antidecubitus mattresses are evaluated, it is often only with regard to aspects of the interface pressure and the mattresses' ability to redistribute the pressure. The review points out the important observation that, to be able to evaluate the efficacy of the antidecubitus mattress, the mattress's effect on tissue viability needs to be studied. The parameters that ought to be considered when evaluating a support surface are: interface pressure, pressure and blood flow distribution, temperature and humidity in the skin-support surface interface. The authors propose that the effect on tissue viability of external loading can be assessed by simultaneous measurement of the interface pressure and tissue perfusion. © IFMBE: 2005.
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- Törnqvist, Rebecka, 1982-, et al.
(författare)
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A framework for planning of sustainable water and sanitation systems in peri-urban areas
- 2008
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Ingår i: Water Science and Technology. - : IWA Publishing. - 1996-9732 .- 0273-1223. ; 58:3, s. 563-570
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Tidskriftsartikel (refereegranskat)abstract
- There are billions of people around the world that lack access to safe water supply and basic sanitation, a situation which puts the affected in severe health conditions as well as economical and social despair. Many of those lacking adequate water supply and sanitation systems can be found at the fringe of the cities in so called peri-urban areas, especially in the developing world. Planning in these areas is highly complex due to challenging environmental and physical conditions, high population density and unclear institutional boundaries. This article presents a framework aiming to support the planning process for sustainable water and sanitation systems in peri-urban areas. The suggested framework is based on different available planning approaches from a review of literature and websites of organisations and companies. It consists of a recommendation of important steps in the planning process as well as supporting tools. Further, it incorporates a set of sustainability criteria important for the peri-urban context and allows for the development of site specific systems. The framework has the aim to be flexible for different planning situations, and for suiting planners with different perspectives and amount of resources.
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