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| 2. |
- Almqvist, Helena, et al.
(författare)
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Organic hazardous substances in graywater from Swedish households
- 2006
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Ingår i: Journal of environmental engineering. - 0733-9372 .- 1943-7870. ; 132:8, s. 901-908
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Tidskriftsartikel (refereegranskat)abstract
- The concentrations of several selected organic hazardous substances were investigated in domestic graywater. In total, 41 of 81 organic hazardous substances were found in concentrations above the detection limits (nonylphenol and octylphenol ethoxylates, brominated flame-retardants, organotin compounds, polyaromatic hydrocarbons, polychlorinated biphenyls, phthalates, linear-alkyl benzene sulfonate, and triclosan). Moreover, total solids, biochemical oxygen demand (BOD7), chemical oxygen demand (COD), total nitrogen, total phosphorus, potassium, and sulphur were investigated and presented for graywater. Another objective was to suggest potential household sources for a selected number of organic hazardous substances. The present and past investigations reveal households to be obvious contributors of organic hazardous substances to municipal wastewater, and that graywater is an important media in this transport. The spreading derives from diffuse household sources like everyday activities (laundry, cleaning, etc.), the wearing down of things such as pipe material and interior fittings, and from airborne deposition.
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- Amofah, Lea Rastas, et al.
(författare)
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Nutrient recovery in a smallscale wastewater treatment plant in cold climate
- 2006
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Ingår i: Vatten. - 0042-2886. ; 62:4, s. 355-368
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- An onsite wastewater treatment plant at Brändön, north of Luleå, receiving primarily treated wastewater from a village, was operated and investigated during one year. The wastewater flow was 0.5 m3/d. The main treatment steps were a prefilter, mainly to distribute the flow, a vegetation filter consisting of two different clones of Salix and two phosphorus filters with Filtralite-P and blast furnace slag (BF slag) operated in parallel. The willow bed reduction of BOD7 was in average about 80% and of phosphorus (P) and nitrogen (N) 20-30%. The main mechanism was believed to be filtration in the bed. The reduction through plant uptake was minor. The Filtralite-P filter reduced BOD7, P and N with 67%, 72% and 20%, respectively. The BF slag filter reduced P and N with 53% and 3%, respectively. The release of sulphuric compounds from the BF slag filter increased the BOD7 content in the effluent. The Filtralite-P system achieved the requirements of the normal protection level given by the Swedish Environmental Protection Agency but not all of the requirements of the high protection level. The BF slag system did not fullfil the requirements of the two protection levels.
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| 4. |
- Andersson-Chan, Anneli, et al.
(författare)
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Kompetens för driftspersonal vid VA-verk : Bakgrund och utveckling
- 2006
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The competence of operators at Swedish water and wastewater treatmentplants is analysed and sorted into four groups. A basis for future educationand continued education is discussed in relation to selected factors ofdevelopment for the surrounding world.
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| 5. |
- Andersson-Chan, Anneli, et al.
(författare)
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Odorous wastewater emissions
- 2006
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Ingår i: Vatten. - 0042-2886. ; 62:3, s. 227-236
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this article is to review odour problems of wastewater treatment facilities and air emission treatment methods. The malodorous wastewater emissions consist of a complex mixture of substances with different properties. A screening of volatile organic and reduced sulphur compounds revealed very low concentrations of individual compounds (< 50 ppb), and only dimethyl sulphide, hydrogen sulphide and methyl mercaptan were found at concentrations above threshold values. Indicating one single compound responsible for the foul odours was not possible. Two case studies are presented and discussed. In the first, a compact biofilter was evaluated for the treatment of gas streams from a sewage pumping station. A rockwool filter media was inoculated with a mixed bacterial wastewater culture that established successfully. However, evaluating the biofilter's performance proved analytically difficult and expensive due to the low concentrations of incoming gases. In the second case study the odour nuisance situation around a wastewater treatment plant was evaluated and a holistic approach to manage the odour problems was developed. An odour panel of local observers worked well, since they got involved in the process. However, using the panel's reports on odour episodes to find the source of the odour was difficult.
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| 10. |
- Grönlund, Erik, et al.
(författare)
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Performance of an Experimental Wastewater Treatment High-Rate Algal Pond in Subarctic Climate
- 2010
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Ingår i: Water environment research. - 1061-4303 .- 1554-7531. ; 82:9, s. 830-839
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Tidskriftsartikel (refereegranskat)abstract
- A pilot-scale experimental high-rate algal pond (HRAP) was investigated in the subarctic mid-Sweden region, at latitude 63°N. During autumn 2002, conditions included temperatures below 10°C and photosynthetic active radiation below 200 µE/m2·s. Biochemical oxygen demand was reduced by approximately 90% (approximately 40 g/m3), chemical oxygen demand by 65% (approximately 80 g/m3), total phosphorus by 20% (approximately 1 g/m3), and total nitrogen by 46% (approximately 15 g/m3), at a retention time of approximately 2.5 days. During autumn 2003, the performance of the HRAP appeared better with a more dense microalgae culture; however, as a result of poor settling of the microalgae, the reduction was considerably lower. A major difference between the years was the microalgae composition. In 2002, the large green algae Coelastrum dominated with Chlamydomonas, Scenedesmus, Lagerheimia, and the Cryptophyte Rhodomonas. In 2003, there was a total dominance of the very small green algae Chlorella, known to be difficult to settle. In batch growth experiments during spring 2002, doubling times of 4 to 6 days were achieved. The period of temperatures above 10°C and an insolation of more than approximately 270 uE/m2·s (125 Langleys), which is well-documented as appropriate for HRAP function (Oswald, 1988a, 1988c), were measured to last for 4 to 4.5 months from early May to late September. However, the growth and treatment performance experiments indicated that a longer season may be possible—6.5 to 7 months, at best—from early April to late October.
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