Avloppsreningsverket i Forsmark renar vattnet med aktivt slam i en satsvis biologisk rening (SBR) reaktor samt med våtmarker. Våtmarkerna består av fyra pulskärr och en damm. Pulskärren är utformade som bassänger fyllda med grus som filtermaterial där ytan är bevuxen. Pulskärren beskickas satsvis med 60 m^3 vatten när någon av SBR-reaktorerna töms, vattnet rinner då ut över ytan samtidigt som det perkolerar ner i bädden. När SBR-reaktorn har tömts är hela pulskärret mättat. Tömningen av pulskärret sker genom ett dränerande gruslager i botten och sedan flödar vattnet vidare ut genom ett ställbart dräneringsrör till slutdammen. Pulskärrens uppgift är att stoppa partiklar och att fungera som ett nitrifierande steg ifall verket i framtiden skulle få ökade reningskrav. I detta arbete har pulskärrens funktion som nitrifierare av ammonium undersökts. Detta genom att sammanställa befintliga driftdata från reningsverket, fältstudier samt en litteraturgenomgång. Målet med fältstudien var att mäta halten ammonium, nitrat och totalkväve i vattnet som gick in och ut ur pulskärret för att se hur halterna ändrades. Dessutom mättes temperatur, syrehalt, pH och konduktivitet. Provtagningen genomfördes på två pulskärr med tömningstiderna två respektive fyra timmar. Resultaten visade att ammoniumhalterna halveras i pulskärren. Inkommande ammonium till pulskärren var cirka 3 mg/l under studien men om ammoniumkoncentrationen skulle öka kommer nitrifikationen antagligen ske i liknande utsträckning. Detta då liknande system påvisat sådana resultat. Ökad tömningstid för pulskärren medför ökad nitrifikation, pulskärren bör därför ställas om så att tömning sker under cirka fyra timmar. För att hitta en optimal tömningstid bör vidare undersökningar göras. Forsmarks avloppsreningsverk möter de reningskrav som ställts med marginal. Trots att detta inte var syftet, avskiljs 80 % av inkommande kväve och det kunde konstateras att den största kväveavskiljningen sker i SBR-reaktorn. Kvävereduktionen har uppstått då verket haft låg belastning samtidigt som mycket syre tillsatts till processen. Då rening genom pulskärr sker efter att vattnet passerat genom SBR-reaktorerna borde luftningen kunna minskas för att istället utnyttja pulskärrens nitrifierande egenskaper. Svensk kärnbränslehantering AB har planer på att leda lakvatten till reningsverket för att avskilja kväverester, skulle detta ske kommer flödena över pulskärren att öka. Att den hydrauliska belastningen ökar borde inte utgöra några problem då flödena troligen inte kommer överstiga pulskärrens kapacitetsgränser. I extrema fall kan tömningstiden på pulskärren minskas. / Forsmark wastewater treatment plant treats wastewater using an active sludge process in sequencing batch reactors (SBR:s) and followed by constructed wetlands. The wetlands consist of four intermittent loaded soil filters (ILS:s) and a pond. The ILS:s is designed as pools filled with filter material and with a plant-grown surface. One of the ILS:s fills up with water when one of the SBR reactors is emptied. The water flows out over the surface as it percolates into the bed. When the SBR reactor is emptied, the entire ILS becomes saturated. The ILS then drains through a drainage gravel layer at the bottom and further through an adjustable drainage pipe into the dam. The purpose of the ILS:s is to work as extra filter for removal of the remaining particles and escaping sludge. They have also been thought to act as a nitrifying step if the plant would have tougher cleaning requirements in the future. In this report, the function of the ILS:s as nitrifying steps was investigated by compiling existing operating data from the treatment plant, with conducted field studies and through a literature review. The field study aimed at measuring ammonium, nitrate and total nitrogen in the water at the entering and the outlet in the ILS to see how the different nitrogen concentrations was affected. Temperature, oxygen, pH and electricalconductivity were also measured. The sampling was done on two ILS with different drainage time, two and four hours. The results showed that the ILS:s nitrifies the incoming water with an average efficiency of 50 % depending on the ammonium contentration in the incoming water. An increased drainage time for the ILS seamed to result in better nitrification. Therefore, the ILS:s should be changed to drain for at least four hours. Should the ammonium concentration increase above 3 mg/l the nitrification rate would probably be about the same. Similar systems such as have shown similar nitrification removal but with higher ammonia concentrations. Forsmarks wastewater treatment plant meets the purification requirements imposed on the plant with margin. It is remarkable that, without planning for any nitrogen removal, the removal is about 80 % of incoming nitrogen, most of which is removed in the SBR reactor. Svensk Kärnbränslehantering AB plans to lead leachate to the treatment plant for nitrogen removal. If this plan is fulfilled, the flows through the ILS will increase. This should not be a problem as the total flow trought the ILS will not exceed the capacity limits of the ILS. In case of high flows, the emptying time of the ILS:s can be reduced.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Pig Slurry (PS) is used mainly as a fertilizer for crops in southern Brazil where the predominant soil management is in no-tillage. Thus, the application of manure on the soil surface can increase losses of nitrogen (N) for volatilization of ammonia (NH3), leading to reduction in the fertilizing potential of waste and increased environmental pollution. Moreover, as the PS are rich in ammonium N, nitrification can occur quickly and easily and the generated nitrate can also be lost by leaching and denitrification. Then, it is necessary to look for alternatives to mitigate these losses of N fertilizer and maximize the potential of the PS. One of the possibilities to enable greater efficiency and lower pig slurry pollution potential is to perform the application in the soil in split doses, while other strategy is the use of nitrification inhibitors (NI). Thus, the amount of ammonium N applied to the soil surface would be divided into smaller fractions rather than a single application, minimizing the losses by NH3 volatilization and with the delay in the appearance of nitrate (NO3 -) the transfer of this anion to lower soil layers. To evaluate these aspects, experiments were conducted in an Ultisol in no-tillage handled in the agricultural year of 2010/2011, on the campus of Universidade Federal de Santa Maria (UFSM). The treatments were arranged in randomized blocks and evaluated in maize, summer of 2010/2011, and wheat, winter of 2011, consisting the application of PS in a single dose (pre-sowing) and split doses (1/3 in pre-sowing and 2/3 in coverage), with and without the use of nitrification inhibitor dicyandiamide (DCD), present in the product Agrotain® Plus (81 % of DCD) and applied at 7.0 kg ha-1. Besides, a treatment with recommended dose of urea N for both cultures and a control treatment without the use of fertilizer were evaluated. Volatilized NH3 was captured inside the semi-open static chambers containing sponge soaked with a mixture of phosphoric acid and glycerin. Soil samples were collected one day after experiments were set up, and on subsequent days to allow the detection of the changes of inorganic N in soil during the development of both cultures. These samples were analyzed for ammonium N and nitrate N according to Tedesco et al. (1995). The nitrification inhibitor (DCD) maintained N of manure applied to the soil in ammonium form without increasing the emission of NH3 to atmosphere, while the application of PS in parts or not did not differ in the amount of volatilized NH3 and in the percolation of nitrate in the soil. / Os dejetos líquidos de suínos (DLS) são utilizados, principalmente, como fertilizante de culturas comerciais na região Sul do Brasil, onde predomina o manejo do solo em sistema de plantio direto (SPD). Assim, a aplicação desses dejetos na superfície do solo pode potencializar as perdas de nitrogênio (N) por volatilização de amônia (NH3), levando a redução no potencial fertilizante dos dejetos e ao aumento da poluição ambiental. Além disso, como os DLS são ricos em N amoniacal fácil e rapidamente pode ocorrer nitrificação e o nitrato gerado vir a ser perdido também por lixiviação ou desnitrificação. Faz-se necessário então buscar alternativas para mitigar essas perdas de N e maximizar o potencial fertilizante dos DLS. Uma possibilidade de viabilizar maior eficiência fertilizante e menor potencial poluente dos dejetos de suínos é realizar a aplicação de forma parcelada no solo, enquanto outra estratégia é a inibição do processo de nitrificação, por meio do uso de um produto inibidor de nitrificação (IN). Dessa forma, a quantidade de N amoniacal aplicada na superfície do solo seria dividida em frações menores do que com aplicação única dos dejetos, minimizando as perdas por volatilização de NH3 e com o retardamento no aparecimento de nitrato (NO3 -) a transferência desse ânion para camadas inferiores do solo. Para avaliar esses aspectos, os experimentos foram conduzidos em um Argissolo manejado em SPD, no ano agrícola 2010/2011, no campus da Universidade Federal de Santa Maria (UFSM). Os tratamentos foram dispostos em blocos ao acaso e avaliados na cultura do milho, verão 2010/2011, e do trigo, inverno 2011, constando da aplicação de DLS em dose única (pré-semeadura) e parcelada (1/3 em pré-semeadura e 2/3 em cobertura), com e sem o uso do inibidor de nitrificação dicianodiamida (DCD), presente no produto Agrotain® Plus (81 % de DCD) e aplicado em 7,0 kg ha-1. Além destes, foram avaliados um tratamento com a dose recomendada de N ureia para as duas culturas e um tratamento testemunha, sem o uso de fertilizante. A NH3 volatilizada foi captada no interior de câmaras estáticas semiabertas, contendo esponja embebida com a mistura de ácido fosfórico e glicerina. Amostras de solo foram coletadas um dia após a instalação dos experimentos e em dias subsequentes para possibilitar a detecção das transformações de N inorgânico no solo durante o cultivo de ambas as culturas. Essas amostras foram analisadas para N amoniacal e nítrico, conforme Tedesco et al. (1995). O inibidor de nitrificação (DCD) preservou o N dos dejetos aplicados ao solo na forma amoniacal sem aumentar a emissão de NH3 para a atmosfera, enquanto o parcelamento ou não da dose de dejetos não diferiu na quantidade de NH3 volatilizada e na percolação de nitrato no solo.

I Sverige finns det ungefär 25 000 riskklassade förorenade områden samt ännu fler områden som potentiellt är förorenade. Naturvårdsverket har tagit fram generella riktvärden för olika förorenade ämnen. Halter över riktvärdena antyder att risken för negativa effekter på människan eller miljön bedöms vara stor och att efterbehandling av området är aktuellt. Ett vanligt, men kostsamt efterbehandlingsalternativ är urschaktning och bortforsling av jord innehållandes halter av ämnen över riktvärdena. Ett intresse finns för att utveckla lätt tillämpbara metoder för platsspecifik riskbedömning av mark i syfte att skydda markmiljön och dess funktioner. Mikroorganismer som ingår i kvävets kretslopp utför nyckelfunktioner i jorden. Flera studier indikerar att dessa mikroorganismers abundans och aktivitet påverkas av flera olika markföroreningar. Inom forskningsprojektet APPLICERA har ett lysimeterexperiment genomförts där två jordar, med olika egenskaper med avseende på bland annat kornstorleksfördelning och pH (svagt basisk sandy loam respektive sur sand), förorenats med koppar respektive PAH:er i varierande halter. Halterna motsvarar riktvärden för känslig markanvändning (KM), mindre känslig markanvändning (MKM) och 3xMKM. Provtagning av jorden har skett vid tre tillfällen under en period av 16 månader. I detta examensarbete har nitrifierande mikroorganismers potential för att användas som indikatorer för förändrad markfunktion i förorenad jord undersökts. Detta har gjorts genom att kvantifiera ammoniakoxiderande arkéer (AOA), ammoniakoxiderande bakterier (AOB) samt de nitritoxiderande bakteriesläktena Nitrospira och Nitrobacter i jord som provtagits vid de olika tidpunkterna i lysimeterexperimentet. Mätning av potentiell ammoniakoxidation (PAO) har skett för jord från det sista provtagningstillfället. Resultaten visade att abundansen av mikroorganismerna generellt var större i den svagt basiska jorden klassificerad som sandy loam än i den sura jorden klassificerad som sand. Med tiden minskade AOA:s abundans för den högsta koncentrationen av koppar och PAH, särskilt utpräglad var minskningen i den sura jorden. Även Nitrospira minskade i abundans i PAH-förorenad jord för båda jordtyperna, dock kunde en minskning i abundans i kopparförorenad jord statistisk endast säkerställas för den sura jorden. AOB:s och Nitrobacters abundans visade inte på någon tydlig uppåt- eller nedåtgående trend varken över tid eller för ökande föroreningshalt. Skillnaden i kvantitet av mikroorganismer mellan jordtyperna antyder att jordens kemiska och fysiska egenskaper påverkade mikroorganismernas abundans såväl som föroreningarnas biotillgänglighet. PAO minskade med ökande kopparhalt för båda jordtyper, däremot sågs en minskning i PAO med ökande PAH-halt endast i den sura jorden. Resultaten antyder att abundansen av AOA och Nitrospiras verkar ha störst potential att utgöra generella indikatorer över ändrad markfunktion, dock lämpligen med komplettering av förbättrade mätningar av PAO för att få mer information om kvävets kretslopp i förorenad jord. / In Sweden there are around 25,000 contaminated areas classified as a risk for human health or the environment, and even more potentially contaminated areas. The Swedish Environmental Protection Agency has developed generic guideline values for hazardous substances.  Contamination levels exceeding the guideline values indicate a large risk for human health or the environment and that there is a need to remediate the site. A frequently used and expensive aftertreatment is excavation and removal of contaminated soil. Therefore, there is an interest to develop easy applicable methods for site-specific risk assessment with the purpose to protect the soil environment and its functions. Microorganisms involved in the nitrogen cycle perform key functions in soil. Several studies indicate that the abundance and activity of N-cycling microorganisms are sensitive to various soil pollution. Within the research project APPLICERA, a lysimeter experiment was conducted with two different soil types (acidic sandy soil and slightly alkaline sandy loam) and different contamination levels of copper and PAH. The contamination levels corresponded to generic guideline values for sensitive land-use (KM), less sensitive land-use (MKM) and 3xMKM. Soil samples were taken at three times during a period of 16 months. The aim of this master thesis was to investigate nitrifying microorganism potential as indicators for altered soil functioning in contaminated soil. Ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB) and the nitrite-oxidizing bacteria genera Nitrospira and Nitrobacter has been quantified in soil samples with the different treatments. Measurements of the potential ammonia oxidation (PAO) have been performed in soil from the last sample taking.  The abundance of the nitrifying microorganisms was in general higher in the slightly alkaline sandy loam soil. Over time there was a decrease in AOA abundance for the highest concentration of copper and PAH, most pronounced in the acidic sandy soil. Also, a decrease in the abundance of Nitrospira in soil contaminated with PAHs could be seen for both soil types. In copper contaminated soil a distinct decrease in the abundance of Nitrospira could only be seen in the acidic sandy soil. The abundance of AOB and Nitrobacter did not show any obvious pattern for different contamination levels or over time. The difference in abundance of nitrifying microorganisms between the soil types suggests that the soil’s chemical and physical characteristics as well as the bioavailability of the contaminant affected their abundance. A significant decrease in PAO could be seen for the highest contamination level of copper for both soil types, but for the PAH contaminated soil PAO decreased only in the acidic sandy soil. These results suggest that the abundance of AOA and Nitrospira seems to have greatest potential as general indicators for altered soil functioning. However, improved activity measurements are needed to gain greater insight into the soil N-cycle functioning in contaminated soils.

This diploma thesis deals with the wastewater treatment technologies by means of which high quality of the treated wastewater is attained, especially with regard to removing nutrients. The introduction of the thesis contains, among others, descriptions of the reserves in the Czech Republic where it is extremely important to insist on the highest quality of the discharged wastewaters. Then follows a summary of the quality requirements on the discharged wastewaters as stipulated in the legislation. Furthermore, I analyse the impact of the nutrients – nitrogen and phosphorus – on the environment and the principles of their removal from the wastewaters. In the next section I concentrate on the technological processes by means of which the required quality of the wastewater is achieved. The conclusion includes a list of technologies used as the tertiary wastewater treatments with emphasis on membrane technologies. The second part of my thesis is a study of a project of a wastewater treatment plant (WWTP) with membrane technology for the villages of Sloup and Šošůvka located within the protected landscape area of Moravian Karst.

No description available.

The majority of the nutrients in household wastewater are found in the urine and in order to facilitate the use the nutrients in the urine as fertilizer, the urine can be can be concentrated. To extract the nutrients from the urine, various technologies for urine concentration are being developed today. As the technologies are relatively new, urine concentration systems have not been installed on a larger scale. In this study, sustainability of three different urine concentration technologies was evaluated through a fictional case study for 2100 people that took inspiration from a planned residential area in Malmö, Sweden, where technology for urine concentration will be implemented in at least one of the buildings. The technologies were evaluated through a multi-criteria assessment (MCA), where different criteria within sustainability categories environment, technical, economic and health were determined based on the Sustainable Development Goals (SDGs). The technologies examined were alkaline dehydration, nitrification-distillation and ion-exchange using a pre-step of struvite precipitation. For the alkaline dehydration technology, fresh urine is added to an alkaline medium, in order to prevent nitrogen losses, and then dried. In the nitrification-distillation technology, stored urine is treated by first being stabilized by a partial nitrification and then distilled in order to reduce the volume. For the ion-exchange and struvite precipitation system, phosphorus is first precipitated from stored urine and nitrogen is then extracted through ion-exchange. The urine concentration technologies were assumed to be installed in semi-centralized treatment plants in basements in the residential area. The other household wastewater was assumed to be treated in the local wastewater treatment plant (WWTP). The results showed that all three urine concentration technologies may contribute to a significant increase in nitrogen recovery from the household sewer. However, this may come at the expense of increased annual costs for the population. Before it is possible to determine whether urine concentration can be an alternative as a complement to the existing wastewater treatment, further studies of the urine concentration technologies and their sustainability are required. However, this study indicated that urine concentration technologies perform well in many of the sustainability criteria examined and therefore have potential to contribute to the SDGs, especially regarding nitrogen recovery. This study can therefore be an incentive for further studies, where the sustainability of an implementation of urine concentration in Sweden is addressed. / Majoriteten av näringen i hushållsavloppsvattnet finns i urinen och för att underlätta användningen av växtnäringsämnena i urinen som gödningsmedel kan den koncentreras. För att utvinna näringen ur urinen utvecklas idag olika tekniker för urinkoncentrering. Då teknikerna är relativt nya har system för urinkoncentrering inte installerats i en större skala. Därför utvärderades hållbarheten för tre olika urinkoncentreringsmetoder genom en fiktiv fallstudie som innefattade 2100 personer. Fallstudien fick inspiration från ett planerat bostadsområde i Malmö, Sverige, där teknik för urinkoncentrering ska implementeras i minst en av byggnaderna. Teknikerna utvärderades genom en multikriterieanalys (MKA), där kriterier inom hållbarhetskategorierna miljö, teknik, ekonomi och hälsa valdes utifrån de Globala målen. De tekniker som utvärderades var alkalisk urintorkning, nitrifikations-destillering och jonbyte där struvitutfällning tillämpades som förbehandling. För den alkaliska urintorkningen tillförs färsk urin till ett alkaliskt medium, för att förhindra kväveförluster, och torkas sedan. I nitrifikations-destillerings tekniken behandlas lagrat urin genom att det först stabiliseras genom en partiell nitrifikation för att sedan destilleras för att reducera volymen. För systemet med jonbyte och struvitfällning, fälls först fosfor från lagrat urin ut och sedan utvinns kvävet genom jonbyte. Urinkoncentreringsteknikerna antogs anläggas i semi-centraliserade reningsverk i källare i bostadsområdet. Övrigt hushållsvatten antogs renas i det lokala avloppsreningsverket. Resultatet visade att samtliga av de tre teknikerna för urinkoncentrering kan bidra till en betydande ökning kväveåtervinning från hushållsavloppet. Dock kan detta komma på bekostnad av ökade årliga kostnader för de boende i området. Innan det är möjligt att avgöra om urinkoncentrering kan vara ett alternativ som ett komplement till den befintliga avloppsreningen i Sege Park krävs vidare studier av urinkoncentreringsteknikerna och deras hållbarhet. Däremot visade denna studie att urinkoncentreringsteknikerna presterar bra i många av de undersökta hållbarhetskriterierna och har därför potential att bidra till de Globala målen, främst när det gäller kväveåtervinning. Denna studie kan därför vara ett incitament för vidare studier som behandlar hållbarheten av en implementering av urinkoncentrering i Sverige.

The expansion of livestock husbandry and biogas production in large parts of northwestern Germany during the last two decades increased the amount of accruing manure, as well as the demand for maize as fodder crop and substrate for biogas plants. To overcome phosphorus deficiency symptoms during early growth of maize, farmers commonly apply mineral starter fertilizers containing ammonium-nitrogen and phosphorus on top of the usual manure applications required to meet crop nutrient demand. This practice typically leads to overfertilization of N and P and the excess nutrients are then prone to be lost into the environment. Recent developments of agricultural machinery allow for the injection of slurry bands into the soil prior to maize planting. Due to high concentrations of ammonium and phosphorus in the manure band, chemical transformation and translocation of these nutrients is reduced. When the bands are placed near the seeds, even the radicles can access the applied nutrients. Hence, application of mineral starter fertilizers might be obviated. Earlier investigations showed insufficient knowledge of nutrient transformations in manure bands and their consequences on crop growth. To resolve these problems a research project at the University of Applied Sciences Osnabrück was conducted in close cooperation with the local agricultural extension services, machinery producers and farmers. In a series of field trials, broadcasting of liquid manure was compared to injection with and without a nitrification inhibitor in three consecutive growing seasons (2013 to 2015). The trials were conducted in a split-plot design, where all liquid manure treatments were divided in subplots with and without a mineral starter fertilizer. Biomass samplings at eight leaves stage and harvest gave insight into the performance of the treatments. Compared to broadcast application with starter fertilizer, manure injection showed slightly retarded early growth in some trials. However, yields and nitrogen uptake at harvest were similar. When a nitrification inhibitor was added to the injected manure, early growth was not retarded, yields were alike broadcast and injection treatments, but nitrogen uptake was higher in all seasons (on average ~7%). To further investigate nitrogen dynamics and crop growth, another field trial was conducted on a sandy soil close to Osnabrück in 2014 and 2015. Manure injection with and without a nitrification inhibitor was compared to broadcast application with mineral starter fertilizer and an unfertilized control treatment. Plant samplings were taken at regular intervals. Major precipitation events in May and June 2014 led to significant nitrate leaching, especially in the broadcast treatment. Manure injection delayed the nitrification of slurry ammonium and consequently the translocation out of the root zone. Thus, plants in injection treatments could accumulate more nitrogen in their biomass and showed less nitrogen deficiency symptoms. This led to increased yield (+16.5%) and nitrogen uptake (+9.6%) for injection treatment with nitrification inhibitor compared to broadcast treatment. In 2015, low temperatures impaired seminal root growth and phosphorus availability. The mineral starter fertilizer in the broadcast treatment led to better early growth than injected slurry. When a nitrification inhibitor was added to the injected manure, less P deficiency symptoms were observed, and the crop growth was only slightly retarded. Due to the high compensation potential of silage maize, these differences were equalized until harvest. Nevertheless, the mean apparent nitrogen recovery efficiency of both seasons was higher in injection treatments with and without nitrification inhibitor, compared to broadcast with mineral starter fertilizer (48%, 56% and 43%, respectively). To ease the handling of field trial series by decreasing the number of tissue samplings, the use of a handheld sensor was tested during vegetative growth of maize. In the series of field trials with the local extension service, the derived vegetation index showed significant correlations to biomass and nitrogen uptake at eight leaves stage. Measurements of the vegetative growth observed during the nitrogen dynamics trial showed that the sensor needs sufficient leaf area to deliver precise data, but also tends to saturate when maize tassels evolve. The best estimates were found between six and ten leaves. Thus, the sensor can be a valuable tool to reduce numbers of tissue samples and, thus, time and effort needed in fertilization trials. Altogether, these results should encourage farmers to obviate mineral starter fertilizers by using manure injection when cropping maize on sandy soils. The advantages that come along with manure injection based on the present research indicate higher shares of manure nutrients find their way into the plants due to delayed biochemical transformations. These nutrients are consequently not lost into the environment. Nitrification inhibitors have shown a positive effect on crop performance and led to a further reduction of nitrogen losses. However, further knowledge of their decomposition with special regard to the ecological impact of their compounds and metabolites need to be thoroughly evaluated.

No description available.

Plants in constructed wetlands serve as carriers for attached microbial growth. They mainly transfer oxygen and release exudates into the root zone. As a result, an area exists around the roots (rhizosphere) in which bacteria are stimulated by root growth. Our goals were to ascertain whether stimulating the microbial community only has a local effect on the rhizoplane, and to establish the importance of this stimulation for wastewater purification in the root zone. Observations were carried out in a planted and an unplanted laboratory batch reactor incubated with an artificial wastewater with a high concentration of ammonia. Samples were taken at intervals of 10 mm away from the roots. The chemical and physical conditions and enzyme activities in soil sections at various distances from the roots affecting the efficiency of microbial nitrogen removal were characterized. An influence on the nitrification and denitrification process was detected via several parameters up to a range of different root distances: microbial parameters such as the total bacterial number, respiratory activity, protein and DNA amount seem to be affected by roots up to a distance of 50 mm from the roots, whereas the oxygen concentration, DOC and redox potential are unaffected at a distance exceeding 20-30 mm. This indicates that improved nitrogen removal is also possible in the wider root surroundings. Given the average root-to-root distance of 35 mm, the root-influenced area could therefore be expanded to the whole rooted zone in a constructed wetland.

Occurrence of organic micropollutants (OMPs) in aquatic environment is a worldwide concern. A long list of anthropogenic substances, including pharmaceuticals, hormones, etc., are frequently detected in natural water sources. Wastewater treatment plants are one main source of OMPs pollution, but also a key step to control OMPs dissemination into the environment. This dissertation focuses on the evaluation of Membrane Aerated Biofilm Reactor (MABR) as a sustainable process to treat wastewater polluted by OMPs. Furthermore, application of high intensity pulsed light is proposed as an innovative tertiary treatment to produce reclaimed water of high quality. In Chapter 1, a literature review was performed to investigate the occurrence and toxicity of 12 selected organic micropollutants (OMPs) in surface and ground water and the limitations of current available biological processes. Among these technologies, systems with enriched nitrifying activity were able to enhance the removal of specific OMPs through cometabolic activities. Thus, I proposed the use of a MABR with enriched nitrifying biomass to treat OMP polluted water. In Chapter 2, I studied the influence of biofilm thickness on the removal of 13 OMPs via MABR. Results demonstrated OMP removal was dependent on biofilm thickness and bacterial cell density. MABR demonstrated important efficiencies in the removal of ammonium, COD, acetaminophen and triclosan at early stages of biofilm thickness. However, the removal of nonpolar, hydrophobic 4 OMPs and anionic, acidic OMPs required thicker biofilms, achieving maximum removal at biofilm with 1.02 mm thickness and 2.2 × 106 cell mL-1. In Chapter 3, the contribution of sorption and biodegradation in the removal of OMPs via MABR was evaluated. At three stages of biofilm thickness studied, biodegradation dominated the removal for most OMPs. Heterotrophs played an important role in OMP biodegradation at all biofilm thickness, while autotrophic nitrifiers enhanced their contribution at thickness beyond 0.58 mm. Increased removal of pollutants like estrone and ethinyl estradiol were linked to the MABR enrichment with nitrifying bacteria. Sorption was essential for the removal of lipophilic and recalcitrant pollutants like triclosan. Finally, to provide high quality treated water for reuse, Chapter 4 explores the use of high-intensity pulsed light (HIPL) as post-treatment. The number of pulses and optical energy dose have a significant impact on the OMPs removal. HIPL demonstrated fast kinetics and efficient photodegradation – with significant OMPs removal within milliseconds. The findings from my Ph.D. dissertation indicate that MABR combined with high-intensity pulse light may be an effective treatment train for the efficient removal OMPs present in municipal wastewaters. This combined treatment process could potentially pave the way to produce high quality reclaimed water for various reuse purposes.