A pilot-scale experimental high-rate algal pond (HRAP) was investigated in the subarctic mid-Sweden region, at latitude 63 degrees N. During autumn 2002, conditions included temperatures below 10 degrees uC and photosynthetic active radiation below 200 mu E/m(2).s. Biochemical oxygen demand was reduced by approximately 90% (approximately 40 g/m(3)), chemical oxygen demand by 65% (approximately 80 g/m(3)), total phosphorus by 20% (approximately 1 g/m(3)), and total nitrogen by 46% (approximately 15 g/m(3)), 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 degrees C and an insolation of more than approximately 270 uE/m(2).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.

Wastewater precipitation ponds (fellingsdams) are conventional stabilization ponds adapted to cold climate by the use of chemical precipitation to attain sufficient removal efficiency of impurities, primarily phosphorus. The objective with this investigation was to study the influence of an interruption of the dosage of coagulant during summer periods at two fellingsdam systems (Orrviken and Lockne) in the middle of Sweden. The investigation took place over two years characterized by unusual precipitation conditions; 2001 was intense in precipitation whereas summer 2002 represented a dry season. The results showed that there is a potential to utilize the summer biological activity in fellingsdams. At Orrviken the effluent quality measured as organic matter and phosphorus in the effluent was just slightly above the values that were reached by chemical precipitation. At Lockne the performance was lower. The organic matter reduction at Orrviken in the summers of 2001 and 2002 were 71 and 67%, respectively, compared to previous years using precipitant when the average was 78%. At Lockne, however, the values in the summers of 2001 and 2002 were 36 and 18%, respectively, compared to previous years using precipitant when the average was 55%. The phosphorous reduction at Orrviken in the summers of 2001 and 2002 were 85 and 89%, respectively, compared to previous years using precipitant when the average was 95%; at the Lockne plant, the phosphorous reduction during the summers of 2001 and 2002 were 60 and 66%, respectively, compared to the previous years' average of 86%. The nitrogen reduction varied considerably over the two summer periods. The reduction at Orrviken was 13% in 2001 and 58% in 2002; the reduction at Lockne was 13% in 2001 and 33% in 2002. Reference values of nitrogen reduction during normal operations were not available

State of the art for fellingsdams - wastewater stabilisation ponds using chemical precipitation - is presented through a field study and from environ-mental reports. Design data are suggested. A system using treated water to irrigate an energy forest is described

Nuläget för fällningsdammar har studerats i ett fältprojekt och från miljörap-porter. Dimensionering av dammar utifrån reell uppehållstid och turbiditet har föreslagits. Den elenergi som omvandlas finns redovisad. Ett dammsys-tem med energiskogsbevattning finns beskrivet.

In residential and rural areas in Sweden, a considerable number of houses are not connected to municipal wastewater treatment plants but the wastewater is treated in on-site sanitation systems. These systems contribute significantly to the anthropogenic discharge of phosphorus. Therefore, further development of small scale wastewater treatment systems is necessary. The aim of this project was to develop a small-scale wastewater treatment system to facilitate nutrient recovery. A full-scale experimental system with two treatment lines for a total flow of 1 m3/d was built. Investigated components of the system were a distribution layer, a willow bed with a root zone, followed by two parallel containers filled with filter materials for sorption of phosphorus. Filter material investigated in full-scale were Filtralite P and blast furnace (BF) slag. Besides the full-scale investigation, filter materials were investigated in laboratory. BF slag was investigated with respect to phosphorus sorption, wollastonite with respect to phosphorus and ammonium sorption and clinoptilolite with respect to ammonium adsorption.In the full-scale experiment suspended solids and organic matter was effectively reduced in the willow bed. The reduction of SS was 93% in average and the reduction of BOD was 86%. The effluent wastewater from the willow bed was sufficiently treated to avoid clogging of the following phosphorus filters. However, the nutrient reduction in the willow bed was moderate. The reduction of both total nitrogen and total phosphorus varied between 10 and 60%.The filter volume of Filtralite P and BF slag used in the full-scale investigation, 2,2 m3, was too small to achieve an efficient phosphorus reduction during one year. The investigated fresh slag sorbed more phosphorus compared to weathered slag. Thus, if the slag is covered during storage to prevent active substances to be leached out by precipitation, the phosphorus sorption of the slag will probably be preserved. BF slag contains sulphuric compounds. In both the laboratory and the full-scale studies, sulphuric compounds leached out when wastewater percolated through the filter. This can be a hinder for using BF slag in a wastewater treatment system.The investigated wollastonite and clinoptilolite can not be recommended to be used in small-scale wastewater treatment with respect to phosphorus and ammonium sorption. The investigated willow clones "Karin" and "Gudrun" could be establish as far north as in Luleå. The biomass production of the second growing season was as high as for salix clones with wastewater in southern Scandinavia.A willow bed combined with a phosphorus filter could be a robust small-scale wastewater treatment method but some components must be further developed.

I Sverige är många hus på landsbygden och i så kallade omvandlingsområden inte anslutna till kommunala reningsverk utan avloppsvattnet behandlas i enskilda system. Dessa system bidar signifikant till det antropogena utsläppet av fosfor. En fortsatt utveckling av småskaliga avloppslösningar är därför nödvändig.Syftet med detta projekt var att utveckla en avloppsanläggning så att fosfor och kväve från avloppsvattnet i så stor utsträckning som möjligt skulle kunna tas till vara. Inom ramen för projektet byggdes en fullskaleanläggning dimensionerad för ett flöde på 1 m3/d med två behandlingslinjer. De anläggningskomponenter som ingick i det undersökta systemet var en spridningszon med efterföljande salixbädd som belastades med avloppsvatten genom rotzonen. Denna följdes av två parallella behållare fyllda med filtermaterial för att sorbera fosfor från avloppsvattnet. De filtermaterial som undersöktes i fullskala var Filtralite P och masugnsslagg. Vid sidan av fullskaleförsöket undersöktes olika filtermaterial med laboratorieförsök. Masugnsslagg utvärderades med avseende på fosforsorption, wollastonit med avseende på fosfor och ammoniumsorption samt klinoptilolit på ammoniumadsorption.Resultaten från fullskaleförsöket visade att suspenderat material och organiskt material reducerades effektivt i salixbädden. Reduktionen av SS var i medeltal 93 % och BOD 86%. Det utgående avloppsvattnet från salixbädden var tillräckligt behandlat för att undvika igensättningar av de efterföljande fosforfiltren. Däremot var reduktionen av näringsämnen i salixbädden inte lika omfattande. Reduktionen av totalkväve var 10-60% och av fosfor 10-60%. Den volym Filtralite P och masugnsslagg som användes i fullskaleförsöket, 2,2 m3, var för liten för att erhålla en höggradig fosforreduktion under 1 år. Den färska slaggen som undersöktes i laboratorieförsök sorberade mer fosfor än gammal slagg. Slutsatsen är att om slaggen är övertäckt vid lagring så att nederbörd inte sköljer ur aktiva substanser bör slaggens sorptionsförmåga bättre bibehållas. Masugnsslagg innehåller svavel. I både laboratorieförsök och fullskaleförsök lakades svavelföreningar ut när avloppsvatten perkolerade genom slaggen. Detta kan vara ett hinder för att använda masugnsslagg i avloppsanläggningar.Utifrån resultaten från laboratorieförsöken kan de undersökta materialen wollastonit och klinoptilolit idag inte rekommenderas för att behandla avloppsvatten med avseende på fosfor och ammonium i en småskalig VA-lösning.De undersökta salixssorterna "Karin" och "Gudrun" kunde etableras så långt norrut som i Luleå och den andra växtsäsongen var produktionen av biomassa i salixbädden i samma storleksordning som för salixodlingar i södra Skandinavien som bevattnats med avloppsvatten.Salixbädden i kombination med ett fosforfilter har potential att bli en robust metod för småskalig avloppsvattenbehandling men vissa anläggningskomponenter måste utvecklas vidare.

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.

Kompetensbakgrunden för driftspersonalen vid svenska vatten- ochavloppsverk inventeras och struktureras i fyra grupper. Grunder förframtida utbildning och fortbildning diskuteras mot bakgrund av valdaomvärldsfaktorer.

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.

En småskalig avloppsanläggning har testats i Brändön norr om Luleå under ett år. 0,5 m3/d slamavskiljt vatten från samhället pumpades till försöksanläggningen som bestod av ett förfilter för att sprida vattnet följt av en sälgbädd och två paralella fosforfilter med Filtralite-P och masugnsslagg. I sälgbädden reducerades BOD7 med 80% medan fosfor- och kväveinnehållet minskade med 20-30%. Huvudsaklig mekanism bedömndes vara filtrering i bädden medan växtupptaget var av ringa storlek. Filtralite-P filtret reducerade BOD7 med 67%; fosfor och kväve med 72% och 20 respektive. Masugnsslaggen minskade fosforinnehållet med 53% och kväveinnehållet med 3%. BOD7-innehållet ökade däremot påtagligt genom slaggfiltret beroende på reducerade svavelkomponenter som frigjordes från slaggen. Systemet med Filtralite-P som adsorbent uppfyllde Naturvårdsverkets krav på normal men inte hög skyddsnivå. Systemet med BF slagg uppfyllde inte dessa krav.

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.

Syftet med denna artikel är att ge en överblick av luktproblem kring avloppssystem och tänkbara behandlingsmetoder för dessa gaser. Illaluktande avloppsemissioner består av komplexa gasblandningar med olika fysiska och kemiska egenskaper. Genomförda mätningar av flyktiga organiska och reducerade svavelföreningar visar att alla ämnen fanns närvarande i väldigt låga koncentrationer (< 50 ppb) och bara svavelväte, dimetylsulfid och metylmerkaptan återfanns i koncentrationer över lukttröskelvärdet. Det gick inte att peka ut ett ämne som ensamt ansvarig för lukten. Två fallstudier presenteras och diskuteras. I det första utvärderas behandling av ventilationsgas från en pumpstation i ett kompakt biofilter. Ett stenullsmaterial inympades med en bakteriekultur från avloppsreningsverket, som etablerade sig och växte till i filtret. Det var dock komplicerat och dyrt att utvärdera effektiviteten hos biofiltret eftersom inkommande gaskoncentrationer var så låga. Syftet med den andra fallstudien vara att utvärdera och att utveckla metoder för att arbeta med luktproblem kring ett avloppsreningsverk. Lokala observatörer användes i en luktpanel, något som skapade ett engagemang och en kunskap kring luktproblemen. Det visade sig dock vara svårt att använda panelens luktsamtal för att hitta källan till luktepisoden.

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.

The addition of coagulant at two fullscale stabilisation pond systems inMidsweden was interrupted during two summer periods. The biologicalmode of working was compared to previous periods of chemical precipitation.The performance decreased slightly during interruption, influenced also bystrong hydraulic variations.

Vid två fällningsdammar i Östersund har kemikaliedoseringen stängts sommartid för att följa biodammsfunktionen. En liten försämring av traditionella utsläppsparametrar noterades. De hydrauliska betingelserna varierade kraftigt

The objective of this paper is to present the mass flows of a number of selected hazardous substances in raw, separate grey- and blackwater from ordinary Swedish households. The Vibyasen housing area was selected for the investigation since its wastewater system has separate flows for grey- and blackwater. Due to the high analytical costs, a limited number of hazardous substances had to be selected and the number of samples restricted. The greywater flow was manually measured and the samples were collected at set time intervals. The blackwater samples were randomly collected from a blackwater tank. A total of 105 selected hazardous substances were measured in both fractions. Of the 24 elements (Ca, Fe, K, Mg, Na, S, Al, Ag, As, Ba, Bi, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Pt, Sb, Sn, Te, Zn) measured in both fractions, 22 were detected in the greywater and 23 in the blackwater. 81 organic substances were selected and measured in both fractions (nonylphenol- and octylphenol ethoxylates, brominated flame-retardants, organotin compounds, PAH, PCB, phthalates, monocyclic aromatics, and triclosan). 46 organic substances were found in greywater and 26 in blackwater. PCB was the only group found in neither grey- nor blackwater. The greywater flow fluctuated, with a specific average flow of 66 L per person and day. The composition of blackwater also fluctuated, with shifting proportions of urine, faeces, and flush water. The specific average blackwater flow was 28.5 L per person and day. The mixture of substances in separate wastewater fractions from Swedish households was too complex to exactly distinguish their specific sources.