<p>Treatment wetlands been showed efficient for reducing pollutant in waste water. In Lajeado – RS, Brazil the landfill has poor leachate water treatment. It is necessary to supplement the treatment plant because they need to reduce BOD, COD and nitrate of the water going to recipient. A subsurface flow wetland (SSF) can be a good choice.  In order to be able to design an efficient SSF it is important to understand how the grain sizes of a substrate affect the reducing of pollutants in waste water. This study focus on two substrate, sand with grain size of 0 - 3 mm and gravel with the grain size of 10 - 20 mm. To see the grain size reduces BOD, COD and nitrate best, the experiment used eight pilot scales SSF for leachate water treatment, four filled with sand and four filled with gravel. Two different flows, four with batch and four used continuous flow; two of each was planted with <em>Thypa angustifolia</em> <em>L</em>. Samples were taken from each wetland every week during a four week period. The results showed that the wetlands with the fine- grained substrate; sand gave the better reduction of BOD, COD and TKN (total kjeldahl kväve). It also showed great reduction in color. Important to notice in this study is the lack of time; more samples are required to be able to establish a pattern.</p>

Treatment wetlands been showed efficient for reducing pollutant in waste water. In Lajeado – RS, Brazil the landfill has poor leachate water treatment. It is necessary to supplement the treatment plant because they need to reduce BOD, COD and nitrate of the water going to recipient. A subsurface flow wetland (SSF) can be a good choice.  In order to be able to design an efficient SSF it is important to understand how the grain sizes of a substrate affect the reducing of pollutants in waste water. This study focus on two substrate, sand with grain size of 0 - 3 mm and gravel with the grain size of 10 - 20 mm. To see the grain size reduces BOD, COD and nitrate best, the experiment used eight pilot scales SSF for leachate water treatment, four filled with sand and four filled with gravel. Two different flows, four with batch and four used continuous flow; two of each was planted with Thypa angustifolia L. Samples were taken from each wetland every week during a four week period. The results showed that the wetlands with the fine- grained substrate; sand gave the better reduction of BOD, COD and TKN (total kjeldahl kväve). It also showed great reduction in color. Important to notice in this study is the lack of time; more samples are required to be able to establish a pattern.

För att främja en hållbar utveckling har FN satt upp 17 vägledande globala miljömål som nationell lagstiftning bör utformas efter, vilket Sverige har gjort. För att se till att miljölagstiftningen följs av verksamheter utövas tillsyn mot vissa typer av verksamheter, bland annat deponier. Deponier är bland annat miljöfarliga för att de kan släppa ut lakvatten till omgivande miljö. Tillsynsmyndigheter för Gräfsåsens avfallsanläggning har anmärkt på att vissa av deras utsläppsvillkor för lakvatten ej uppnås. Studien ska, med utgångspunkt från relevanta faktorer för val av reningsteknik (emissionskrav, lakvattnets karaktärisering &amp; lakvattenproduktion), gällande villkor från utsedda tillsynsmyndigheter och styrdokumentet BREF utreda två lämpliga system avreningstekniker för lakvatten samt eventuella återupprepande reningssteg, vid Gräfsåsens avfallsanläggning. Hänsyn kommer även tas till tidigare genomförda pilotstudier för lakvattenhantering vid Gräfsåsens avfallsanläggning, och vilka övergripande slutsatsersom kan dras från dem. Karaktäriseringen utgick från att inhämta historiska data från provtagningar, som jämfördes med BREF:s riktvärden för relevanta parametrar samt nuvarandeutsläppsvillkor. Resultaten visade att reningsteknikerna skulle inriktas mot avskiljning av organiskt material (TOC &amp; BOD7), långkedjiga PFAS, totalt oorganiskt kväve samt totalkväve. Försedimenteringsdamm valdes för att jämna ut lakvattenflödet samt minska mängdenorganiskt material och metaller som kan försämra biologisk rening. Luftad damm och översilningsyta valdes för att de kan minska mängden kväve, organiskt material ochmetaller. Skumfraktionering och adsorptionsfilter valdes för att effektivt avskilja långkedjiga PFAS. Studien har visat att Gräfsåsens avfallsanläggning behöver installera en försedimenteringsdamm samt utöka sin biologiska rening. Tidigare använda reningstekniker som luftad damm, adsorptionsfilter samt våtmark har ej optimeratstillräckligt. / To promote sustainable developement, the UN has set up 17 global environmental goals that national legislation should incorporate. To ensure that environmental legislation is followed by certain practioners, supervision is performed. Landfills are seen as an environmentally hazardous activity that need supervision, mainly due to the fact that environmentally hazardous substances like leachate water could be spread to the environment. Supervisory authorities for Gräfsåsen avfallsanläggning have noted that some of their emission requirements for leachate water are not fulfilled. The study shall, based on relevant factors for the selection of treatment technology (emission requirements, characterization of leachate &amp; production of leachate), current conditions from appointed supervisory authorities, the steering document BREF, investigate two suitable systems of treatment techniques for leachate, at Gräfsåsens avfallsanläggning. Consideration will also be given to previously completed pilot studiesfor leachate management at Gräfsåsens avfallsanläggning, and general conclusions that can be drawn from them. The characterization was based on gathering historical measurement data, and then compare the data to BREF guideline values for relevant parameters as well as current emission requirements.The results showed that treatment techniques should be aimed at removing organic matter, long- chained PFAS, total inorganic nitrogen &amp; total nitrogen. Pre- sedimentation ponds were chosen to even out the leachate flow and reduce the amount of organic matter and metals that could impair biological treatment. Aerated pond and overflow area were chosen because they can reduce the amount of nitrogen, organic matter and metals. Foamfractionation and adsorption filter was chosen to efficiently separate long-chained PFAS. The study has shown that Gräfsåsens avfallsanläggning needs to install a presedimentation pond and expand its biological treatment. Previously used treatment techniques such as aerated pond, adsorption filter and wetlands have not been sufficiently optimized / <p>2023-06-02</p>