From the Proceedings of the 1971 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 22-23, 1971, Tempe, Arizona / The nitrogen balance of a watershed near the city of New Prague, Minnesota was evaluated as part of an overall study on lake and stream eutrophication. Although the n-balance of a humid Midwest watershed cannot be expected to be identical to that of an arid watershed, the processes are the same and differences should be mainly quantitive. Sources of input and causes of depletion are reviewed for 4 points in the nitrogen cycle: the atmospheric zone, the soil-atmosphere interface, the plant-root and soil-water zone and the surface water zone. In the New Prague watershed, commercial fertilizer and bulk precipitation were the major sources of input, contributing, respectively, 53% and 34.4% of the total input of 2.34 million lb/yr. Crop yield and soil or groundwater storage contributed 52.1% and 20.4% of non-enrichment depletions. The closeness of the values of crop yield and commercial fertilizer application was an unfortunate coincidence and is certainly not an indication that the entire fertilizer supply was taken up cry crops. In an arid environment, free from fertilized agriculture, bulk precipitation probably provides the major source of nitrogen compounds.

From the Proceedings of the 1978 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 14-15, 1978, Flagstaff, Arizona / Algal growth and oxygen evolution at the soil -water interface of soil recharge basins intermittently flooded with secondary sewage effluent (SSE) produced diurnal fluxes in dissolved oxygen (DO) in the SSE and redox potentials (Eh) in the SSE and the surface soil of the basin. The maximum daily DO-% saturation in the SSE during flooding ranged from 30 to 450 %, depending on the length of flooding and seasonal effects of temperature and solar radiation. Diurnal cycles of Eh in the SSE and the top 0 to 2 cm of soil indicated that oxygen production by algae and bacterial nitrifying and denitrifying reactions at the soil-water interface are occurring daily for limited periods during flooding and that these reactions might contribute to the net-N removal and renovation of SSE by soil filtration.

Effektiviteten av automatiserade reningsprocesser inom avloppsreningsverk beror ytterst på kvaliteten av de mätdata som fås från installerade instrument. Givarfel påverkar verkens styrning och är ofta anledningen till att olika reglerstrategier fallerar. Idag saknas standardiserade riktlinjer för hur instrumenteringsarbetet på svenska reningsverk bör organiseras vilket ger begränsade förutsättningar för reningsverken att resurseffektivt nå sina utsläppskrav. Mycket forskning har gjorts på att optimera olika reglerstrategier men instrumentens roll i verkens effektivitet har inte givits samma uppmärksamhet. Syftet med detta examensarbete har varit att undersöka hur instrumentering på reningsverk kan organiseras och struktureras för att säkerställa mätdata av god kvalitet och att undersöka effekter av givarfel på reningsprocessen. Inom arbetet genomfördes en litteraturstudie där instrumentering på reningsverk under-söktes. Effekter av givarfel på reningsprocessen undersöktes genom att simulera en fördenitrifikationsprocess i Benchmark Simulation Model no. 2 där bias och drift implementerades i olika givare. Simuleringar visade att positiva bias (0,10–0,50 mg/l) i en ammoniumgivare inom en kaskadreglering bidrar till att öka luftförbrukningen med cirka 4–25 %. Vidare resulterade alla typer av fel i DO-givare i den sista aeroba bassängen i en markant större påverkan på reningsprocessen än samma fel i DO-givare i någon av de tidigare aeroba bassängerna. Om den sista aeroba bassängen är designad för att hålla lägre syrehalter är DO-givaren i den bassängen den viktigaste DO-givaren att underhålla. Positiva bias (200–1 000 mg/l) i TSS-givare som används för att styra uttaget av överskottsslam bidrog till kraftiga ökningar av mängden ammonium med cirka 29–464 % i utgående vatten. Negativ drift i DO-givare visade att stora besparingar i luftningsenergi, cirka 4 %, var möjliga genom ett mer frekvent underhåll av DO-givarna. Huruvida ett instrument lider av ett positivt eller negativt givarfel, bias eller drift, kommer att påverka hur mycket och i vilken mån reningsprocessen påverkas. Studien av givarfel visade att effekten av ett positivt eller ett negativt fel varierade och att effekten på reningsprocessen inte var linjär. Effekten av givarfel på reningsprocessen kommer i slutändan att bero på den implementerade reglerstrategin, inställningar i regulatorerna och på den styrda processen. / The effectiveness of automated treatment processes within wastewater treatment plants ultimately depend on the quality of the measurement data that is given from the installed sensors. Sensor faults affect the control of the treatment plants and are often the reason different control strategies fail. Today there is a lack of standardized guidelines for how to organize and work with online sensors at Swedish wastewater treatment plants which limits the opportunities for treatment plants to reach their effluent criteria in a resource efficient manner. Much research has been done on ways to optimize control strategies but the role of sensors in the efficiency of the treatment plants has not been given the same level of attention. The purpose of this thesis has been to examine how instrumentation at wastewater treatment plants can be organized and structured to ensure good quality measurement data and to examine how sensor faults affect the treatment process. Within the thesis a literature study was conducted where instrumentation at wastewater treatment plants was examined. The effects of sensor faults were examined by simulating a pre-denitrification process in Benchmark Simulation Model no. 2 where off-sets (biases) and drift where added to measurements from different implemented sensors. The simulations showed that positive off-sets (0.10–0.50 mg/l) in an ammonium sensor within a cascaded feedback-loop adds to the energy consumption used for aeration by roughly 4-25%. It could further be shown that all types of faults in a DO sensor in the last aerated basin had significantly larger effect on the treatment process than the same fault in any of the other DO sensors in the preceding basins. If the last aerated basin is designed to have low DO concentrations the DO sensor in that basin is the most important DO sensor to maintain. Positive off-sets (200–1 000 mg TSS/l) in suspended solids sensors used for control of waste activated sludge flow contributed to large increases of ammonia, by 29-464%, in effluent waters. Negative drift in DO sensors showed that significant savings in aeration energy, roughly 4%, was possible to achieve with more frequent maintenance. Whether a sensor is affected by a positive or a negative fault, be it off-set or drift, will affect how much and in what way the treatment process will be affected. The study of sensor faults showed that the effect of a positive or a negative fault varied and that the effect on the treatment process was not linear. The effect of a sensor fault on the treatment process will ultimately depend on the implemented control strategy, settings in the controllers and on the controlled process.

The work is focused on the development of an environmentally friendly external thermal insulation composite system in terms of product composition and composition of the whole system. The intention is to develop an alternative to standard external thermal insulation composite systems. Undoubtely, standard systems have a contribution to energy savings (primary role), but their actual production and composition is also a burden on the environment. The research is focused onthe development of adhesive and leveling substance and plaster using progressive material with phase transformation and energy by-product (fly ash). Furthermore, it is focused on the selection of insulation from renewable sources. Therefore, there is paid attention to the overall composition of the thermal insulation system in order to achieve the most effective impact with respect to the environment. The goal is to achieve secondary energy and resource savings due to the composition of components and also the composition of the entire system.

Lustgas är en växthusgas, ca 300 gånger mer potent än koldioxid och som har potential att bryta ned ozonlagret med sin livslängd på 120 år i atmosfären. Lustgasutsläppen beräknas ha ökat med mellan 20–30% sedan förindustriell tid vilket tros bero på en ökad användning av konstgödsel i jordbrukssektorn men en del av all lustgas som bildas kommer från avloppsreningsverk vilka står för ca 1,6% av lustgasavgången till atmosfären där Henriksdals reningsverk bidrar med lustgasproduktion. Under 2021 beräknade man en lustgasavgång från Henriksdals reningsverk på ca 37 ton, vilket kan jämföras med klimatavtrycket på 10 000 nyregistrerade bilar vid körningar på ca 1500 mil/år. Syftet med rapporten var att undersöka om det gick att beräkna mängden kväve i avgående lustgas och jämföra det med hur mycket av den beräknade lustgasen som avgår till luft av andelen renat ammonium, samt att undersöka olika strategier för minimering av lustgasproduktion. Det finns flera vägar till lustgasbildning i de biologiska reningsprocesserna i verket. Tre huvudspår finns dock till lustgasbildning varav autotrof nitrifikation var aktuell för detta examensarbete. Flera driftsstrategier finns att tillgå för att undersöka hur lustgasproduktion påverkas av olika faktorer. Under detta examensarbete undersöktes en av dessa, syrebörvärden, där ett fast syrevärde i den luftade bassängen antingen skulle minska eller öka lustgasproduktionen beroende på luftningsintensitet och ammoniumkoncentration i vattnet. Lustgasavgången beräknades bestå till 0,19% av kväve renat från ammoniumbelastningen. Resultatet visade att vid låga syrehalter i vattnet fanns en lägre andel lustgasbildning jämfört med högre luftningsintensitet. Nackdelen blev dock att andelen renad ammonium sjönk i blocket. Vid högre luftningsintensitet var lustgasavgången högre i ett av huvudscenariona. I det andra scenariot med hög luftning var andelen renat ammonium lägre än i första scenariot, men med låga lustgashalter. Slutsatsen blev att lustgas kan bildas under olika förutsättningar men att under just den här studien var lustgasproduktionen som högst när nitrifikationen var som mest effektiv. / Nitrous oxide is a greenhouse gas, almost 300 times more potent than carbon dioxide, and which has the potential to deplete the ozone layer with its lifetime of 120 years in the atmosphere. Nitrous oxide emissions are estimated to have increased between 20–30% since pre-industrial times, which is believed to be due to increased use of artificial fertilizers in the agricultural sector, but part of all nitrous oxide that is formed comes from wastewater treatment plants, which account for approx. 1.6% of nitrous oxide emissions to the atmosphere where Henriksdals treatment plants contribute to nitrous oxide production. In 2021, nitrous oxide emissions from Henriksdal's treatment plant were calculated to be approximately 37 tons, which can be compared to the climate footprint of 10,000 newly registered cars driven approximately 15 000 km per year. The aim of the report was to investigate whether it was possible to calculate the amount of nitrogen in outgoing nitrous oxide to compare it with how much of the calculated nitrous oxide is emitted to air from the proportion of purified ammonium, as well as to investigate different strategies for minimizing nitrous oxide production. There are several routes to the formation of nitrous oxide in the biological purification process in the plant. There are, however, three main tracks for nitrous oxide formation, of which autotrophic nitrification was relevant for this degree project. Several operational strategies are available to investigate how nitrous oxide production is affected by various factors. During this thesis, one of these, oxygen set-point, was investigated, where a fixed oxygen value in the aerated basin would either decrease or increase nitrous oxide production depending on aeration intensity and ammonium concentration in the water. The nitrous oxide discharge was calculated to consist of 0.19% nitrogen purified from the ammonium load. The result showed, that at low oxygen levels in the water, there was a lower proportion of nitrous oxide formation compared to higher aeration intensity. The disadvantage, however, was that the proportion of purified ammonium decreased in the block. At higher aeration intensity, nitrous oxide emissions were higher in one of the main scenarios. In the second scenario with high aeration, the proportion of purified ammonium was lower than in the first scenario, but with low levels of nitrous oxide. The conclusion was that nitrous oxide can be formed under different conditions, but during this study, nitrous oxide production was highest when nitrification was most efficient.

A two-year lysimeter study was undertaken to compare the environmental effects (e.g. nitrate leaching and nitrous oxide emissions) of soil applied lactose-depleted dairy factory effluent (LD-DFE) with lactose-rich DFE. The aim of this experiment was to determine the fate of nitrogen from LD-DFE and dairy cow urine applied to a Templeton fine sandy loam soil (Udic Ustrochrept), supporting a herbage cover of ryegrass (Lolium perenne) and white clover (Trifolium repens). Measurements were carried out on the amount of nitrogen lost from the soil via leaching, lost by denitrification, removed by the pasture plants, and immobilized within the soil organic fraction. Further, a comparison between the fate of nitrogen in LD-DFE irrigated onto land under a "cut and carry" system, as opposed to a "grazed" pasture system was undertaken. Lactose-depleted dairy factory effluent was applied at three-weekly intervals during the summer months at rates of 25 and 50 mm, until nitrogen loading targets of 300 and 600 kg N ha⁻¹ yr⁻¹ had been achieved. Measured leaching losses of nitrogen averaged 2 and 7 kg N ha⁻¹ yr⁻¹ for Control 25 and Control 50 treatments; 21, 20 and 58 kg N ha⁻¹ yr⁻¹ for 25 and 50 mm "cut and carry" treatments respectively; and 96 kg N ha⁻¹ yr⁻¹ for the 25 mm "grazed" treatment. The range of nitrate-N leaching loss from LD-DFE plus urine is no different from the lactose-rich DFE nitrate leaching loss. Uptake of nitrogen by the growing pasture averaged 153, 184,340,352,483, and 415 kg N ha⁻¹ yr⁻¹ for Control 25, Control 50, LD-DFE 25 and LD-DFE 50 mm "cut and carry" treatments, and the LD-DFE 25 mm "grazed" treatment, respectively. Denitrification losses were 0.06, 4.4, 1.69, 19.70, and 7.4 kg N ha⁻¹ yr⁻¹ for Control 25, the LD-DFE 25 "cut and carry" treatments, the LD-DFE 25 mm "grazed" treatment, and calculated "paddock losses", respectively. Isotopic nitrogen studies found that 29.4 and 25.8% of applied LD-DFE nitrogen was immobilised in the LD-DFE 25 and LD-DFE 50 "cut and carry" treatments. The results of this experiment confirm the findings of the previous lactose-rich DFE study, in that the effects of grazing stock are of greater environmental concern than the removal of lactose from the effluent waste stream.

Biological nutrient removal has been studied and applied for decades in order to remove nitrogen and phosphorus from wastewater. However, more anthropogenic uses and the continued demand for water have forced the facilities to operate at their maximum capacity. Therefore, the goal of this thesis is to obtain more compact systems for nutrient removal from domestic wastewater. In this sense, optimization and long-term stabilization of high volume exchange ratios reactors, treating higher volumes of wastewater, have been investigated. With the same target, aerobic granular sludge was proposed as a reliable alternative to reduce space and increase loading rates in treatment plants. However, the low organic loading rate from low-strength influents (less than 1 Kg COD•m-3d-1) results in slower granular formation and a longer time to reach a steady state. Because of that, different methodologies and operational conditions were investigated in order to enhance granulation and nutrient removal from domestic wastewater. / L’estudi de l’eliminació biològica de nutrients s’ha dut a terme durant dècades. Tot i això, la influencia de l’home i l’augment de la demanda d’aigua han forçat a les instal•lacions a treballar a la seva capacitat màxima. Així, l’objectiu de la tesi és obtenir sistemes més compactes per a l’eliminació de nutrients de les aigües residuals. En aquest sentit, s’ha investigat l’optimització i estabilització de reactors amb alts volums d’intercanvi, tractant més aigua. Amb el mateix objectiu, el fang granular aeròbic va ser proposat com una alternativa fiable per tal de reduir l’espai i incrementar les càrregues de les depuradores. Tot i això, la granulació amb influents de baixa càrrega (menors a 1 Kg dQO•m-3d-1) resulta més lenta i més dificultosa alhora d’obtenir l’estat estacionari. Per aquesta raó es van investigar diferents metodologies i condicions d’operació per tal de millorar la granularció i l’eliminació de nutrients de les aigües urbanes.

En Bretagne, les « marées vertes » sont récurrentes depuis le début des années 70 et occupent une place importante dans le débat public en terme sanitaire, politique et économique. Lors de cette thèse, une large revue bibliographique a été réalisée sur l’export d’azote et une méthodologie innovante a été mise en place afin d’étudier la variabilité spatio-temporelle de l’export de nutriments dans 2 bassins versants à algues vertes à une échelle intra-annuelle et pendant des évènements extrêmes (évènements pluvieux, période touristique de basses eaux,…). Les bassins versants sélectionnés pour les expérimentations de terrain sont l’Ic et le Frémur (Côtes d’Armor). 3 types d’expérimentations ont été réalisées sur ces bassins versants : 1) Des campagnes de prélèvements ponctuels par temps sec et par temps de pluie (32 stations, 27 campagnes) ; 2) des prélèvements automatiques en crue (3 stations, 8 crues) ; et 3) la mesure haute fréquence (2 stations, en continu). Les paramètres hydrologiques et physico-chimiques classiques, les matières en suspension, les spectres UV et toutes les formes de macronutriments (carbone, azote, phosphore) ont été analysés lors de ces expérimentations. Les résultats obtenus confirment pour une part un certain nombre de résultats de la littérature. D’autre part, il met en lumière la relation carbone/nitrates, jusqu’à présent peu étudiée à différentes échelles spatio-temporelles et pendant des évènements pluvieux, qui semble pourtant primordiale dans la compréhension des phénomènes d’export de nitrates à l’échelle de l’année. Enfin, l’analyse de toutes les formes de nutriments révèle l’importance des formes particulaires issues de l’érosion des sols. Ces résultats soulèvent de nombreuses questions de recherche qui mériteraient un approfondissement afin d’améliorer la connaissance des transferts de nutriments dans les bassins versants et prioriser les actions de remédiations. Les perspectives de ce travail sont à la fois scientifiques et pratiques. Au niveau scientifique, les efforts de recherche sur la relation carbone/nitrate et l’identification de la fraction de carbone organique assimilable par les organismes dénitrifiants doivent être poursuivis. De même, l’amélioration des connaissances sur l’export de nutriments en crue passe par l’identification précise des sources de nutriments particulaires pendant les crues printanières. Au niveau pratique, il doit contribuer à l’amélioration des pratiques agricoles, à la reconnaissance de l’intérêt des zones humides naturelles et à l’amélioration des types de traitement utilisés par les stations d’épuration. Les résultats obtenus lors de cette étude devraient notamment être mis en relation avec la dynamique des nutriments observée dans l’estran pendant la période de développement des algues vertes. Enfin, un effort d’amélioration de l’accès à certains type de données sur les bassins versants est nécessaire afin d’améliorer la compréhension des transferts de nutriments. / In Brittany (Western France), "green tides" are recurrent since the early 70s and have an important place in public debate in health, political and economic terms. In this thesis, a wide bibliographic review was performed on the export of nitrogen, and an innovative methodology has been set up to study the spatial and temporal variability of nutrient export in two coastal watersheds on an intra-annual basis and during extreme events (rainfall events, tourist periods of low water, ...). Watersheds selected for the field experiments are Ic and Frémur (Côtes d'Armor). 3 types of experiments were performed on these watersheds: 1) Campaigns of grab samples by dry and wet weather (32 stations, 27 campaigns); 2) automatic sampling during floods (3 stations, 8 floods); and 3) high frequency measurement (2 stations, continuous). Conventional hydrological and physicochemical parameters, suspended solids, UV spectra and all forms of macronutrients (carbon, nitrogen, phosphorus) were analyzed during these experiments. The results confirm in part a number of results of the literature. Furthermore, it highlights the relationship carbon / nitrates far little studied at different spatial and temporal scales and during rainfall events, which however seems to be crucial in understanding of nitrate export. Finally, the analysis of all forms of nutrients reveals the importance of particulate forms from soil erosion. These results raise many research questions that merit further development in order to improve knowledge on nutrient transfers in watersheds and prioritize remediation actions. The prospects of this work are both scientific and practical. At the scientific level, research efforts on the relationship carbon / nitrate and identification of the assimilable fraction of organic carbon by denitrifying organisms must be continued. Similarly, the knowledge on nutrient export must be improved through the precise identification of particulate nutrient sources during the spring floods. On a practical level, it should contribute to the improvement of agricultural practices, the recognition of the interest of natural wetlands and improvement of the types of treatment used by treatment plants. The results obtained in this study should in particular be linked to the dynamics of nutrients in the foreshore observed during the development of green algae. Finally, an effort to improve access to certain types of data on watersheds is needed to improve understanding of nutrient transfers.