AbstractDue to a growing concern towards issues of sustainability and sustainable development as well as resource scarcity there is a need for increased local cultivation. Cold climate conditions in Sweden make greenhouses necessary for the cultivation of many species. In order to increase the sustainability of greenhouse production processes water cycles should be nearly closedloop cycles. To demonstrate this in practice the Berga Greenhouse project under development by the Centre for Health and Building at the Royal Institute of Technology is used to provide a visionary example. Through precipitation data and a water budget analysis a water reclamation rate of 85% was determined in order to bring the facility to water neutral status. On site water treatment through the use of ecological engineering was analyzed through the use of a multiple-case study of three prevalent technologies (Living Machines®, Organica Water, and Solar Aquatics™) which determined that Living Machines® was the most appropriate technology based upon factors related system performance and footprint.

The wastewater industry is critical for both current and future human life. At the same time, competitive conditions of market spaces lead to technology evolution reaching continuously new frontiers. While many wastewater treatment plants are designed identically in different global loci, wastewater characteristics are unique and therefore decisions related to wastewater treatment technologies are very critical. Wastewater characteristics vary due to cultural and climate factors, among other things and thus, each wastewater treatment technology must be studied independently. Hence, decision analysis and decision making are an integral part of the industry. A multi criteria decision analysis (MCDA) has been applied in this thesis, including a fictional decision-making problem. Furthermore, this thesis describes an analytic approach to a complex decision-making problem in wastewater treatment by using multi attribute utility theory (MAUT). This thesis assigns utility values, applies Swing Weighting (SW) which is not commonly used in the wastewater industry and assesses weight coefficients for the utility functions for each criterion. The goal is to illustrate how proportional scoring can be used to assign utility values in different aspects related to wastewater treatment, how SW can be performed to assess weight coefficients that are related to wastewater treatment and finally how the additive utility can be applied to deliver the total utility. For this reason, a hypothetical decision problem was developed, in which, the decision maker can select amongst three different wastewater treatment technologies using sustainability criteria. This is a multi-dimensional problem that requires the use of a structured approach to analyze the options accordingly. More, six criteria are used to rank three different wastewater treatment technologies with respect to sustainability. Finally, the MCDA results from this hypothetical decision problem show how proportional scoring, SW, and the additive utility could be used in the selection of a wastewater treatment technology however it should be tested with real life decision problems.

During the latest decades, there have been indications that the limiting nutrient are changeable in the Bothnian Sea. The current national regulations for wastewater treatment plants which have coastland towards the Gulf of Bothnia have no regulations regarding nitrogen purification, as these basins traditionally has been seen to have phosphorus-limited conditions. The aim of this study was to investigate how the temporal change of phosphorus and nitrogen has developed during the years 1991-2021 in the Bothnian Sea and if there were any differences between coastal and offshore stations. The ultimate goal was to give an overview of the nutrient situation and develop a guideline whether the current regulations for wastewater treatment plants are sufficient. Three coastal and two offshore stations were studied at the depth 0-10 m by investigating data from national monitoring programs, using trend analysis and comparison of means. The result showed that phosphorus is increasing in all the sampling stations. Consequently, the limited nutrient has evolved towards being more nitrogen-limited. The nitrogen load has instead been larger at the coastal compared to the offshore stations, especially for locations affected by river inlets. However, the conclusion according to this study is that the current regulations are sufficiently. This is due to the more recent shift towards nitrogen-limited conditions at the stations affected by river inlets and the high contribution with phosphorus-rich water from the Baltic Proper, as at the same time wastewater treatment plants is not the greatest contributor to the nitrogen load in the Bothnian Sea.

This master thesis gives an account for various aeration schemes that are utilized in conventional activated sludge treatment process in a wastewater treatment plant. By altering between different aeration schemes, the project aimed at reducing energy consumption along with maintaining the treatment performance at the plant. A series of experiments on the treatment performance over several different aeration schemes thus has been conducted on site at Solviken in Mora, Sweden. The project is basically a case study where no parameters were manually controlled except for the aeration schemes at the plant. Energy consumption reduction is logically relative to the ratio between aeration and non-aeration intervals. Several criteria were tested in regards to the treatment performance, including pH value, organic matters, phosphorus substances and microorganisms. The study has come up with a superior aeration scheme for the plant, as well as indicated processes that can be improved at the plant.

Eutrophication of the Baltic Sea has been an issue for decades and the pollution constantly continues with oxygen deficient bottoms and a damaged marine life as a result. One of the main causes of eutrophication are elevated levels of the nutrient phosphorus. Phosphorus leaks to the sea from various human activities such as agriculture, animal farming and sewage. In Sweden, the onsite wastewater treatment systems are a big problem since they load the Baltic Sea with nearly as much phosphorus as all Swedish municipal wastewater treatment plants. The need for a reduced impact on the Baltic Sea is major and the individual wastewater treatment systems must therefore be looked over. While phosphorus is a contributing factor to eutrophication, it is one of the most important nutrients for all life. Phosphorus builds up our DNA, helps transport of various substances in and out of our cells and provides energy to the cell's processes. We would simply not be able to survive without phosphorus. We ingest phosphorus through the food we eat, which in turn is dependent on fertilizers containing phosphorus. Phosphorus is mined from phosphate ore and the majority of it is used to produce fertilizers. Unfortunately, phosphate ore is not a finite resource and in the last few years it has been realized that the economically extractable phosphorus is a dwindling resource. To be able to produce food for the world's growing population, we need to find ways to recycle phosphorus. In individual drainage systems there is a large potential to catch up phosphorus and then reuse it on agricultural land. This thesis deals with the problems of onsite wastewater treatment systems and suggests measures to improve their status. Ways to recycle phosphorus in combination with having a well-functioning drainage is being investigated and difficulties about the regulations are being discussed. To recover phosphorus and at the same time reduce the burden on the environment should be seen as an incredibly important action, since our sea’s health is acute but lack of the nutrient could have devastating consequences.

The upflow anaerobic sludge blanket (UASB) reactor is widely used around the world to treat variety of domestic andindustrial wastewater with three main advantages: production of biogas as renewable energy, no need of support structure for development of microorganisms and high rate treatment efficiency with low rate of biomass production. This study evaluates the effect of temperature on biogas production and CODtotal removal in Line 4-UASB system treating domestic wastewater in Hammarby Sjöstadsverk. Eight parameters were examined including the following: Influent and effluent temperature, pH, influent CODtotal, influent rate, effluent CODtotal, volatile fatty acids, biogas production rate and methane concentration. There are eight set temperature and each is stabilized for seven days. The biogas production analysis is focus on UASB 1. Temperature rising from 19°C to 35°C achieves a general benefit result in methane yield rate and CODtotal removal efficiency. The best methane yield rate and CODtotal removal rate are 0.167l/gCODtotal and 56.84% respectively at highest working temperature 33.4°C with OLR 3.072gCODtotal/(l*day) and HRT 4.2h. / Den ökande energiförbrukningen i världen och utsläpp av växthusgaser (GHG) gör det nödvändigt att söka nya hållbara energikällor för att matcha efterfrågan på energi i framtiden. Rötningsteknik med organiskt avfall som förnybar energikälla, ger biogas som i genomsnitt består av 78% CH4, 22% av CO2och spår av H2S (<0.5%), är en idealisk kostnadseffektiv metod. Den Uppåt flödande anaeroba slambäddsreaktorn(UASB) med största fördelarna: biogasproduktion som förnybar energi, hög belastning och hög behandlingseffektivitet med låg produktion av biomassa, inget behov av stödstruktur för utveckling av mikroorganismer, är den viktigaste typen för anaerobt reningssystem. Det finns flera faktorer som påverkar UASB-reaktorns prestanda, såsom temperatur, pH, HRT, Uppåtriktat flödeshastighet, OLR, SRT och VFA. I denna studie är huvudsyftet att med fokus på utvärdering av temperaturpåverkan på biogasproduktion och CODtotal avlägsnat i UASB-systemet Linje 4 som behandlar hushållsspillvatten i Hammarby Sjöstadsverk. Analysen avbiogasproduktionen fokuserades på UASB reaktor 1. Åtta parametrar övervakades för att kontrollera skick inklusive inflöde och utflöde, temperatur, pH, CODtotal inflöde, strömningshastighet för inflöde, CODtotal utflöde, flyktiga fettsyror VFA, biogasproduktionstakt och metankoncentration. Försöken utfördes vid åtta inställda temperaturnivåer och varje nivå stabiliserades i sju dagar. pH och VFA-värde var stabilt under hela försöket. Resultatetvisar att temperaturen har en större inverkan på metanavkastningen och CODtotal avlägsnat än belastningen, OLR. Då temperaturen höjs från 19°C till 35°C erhålls en större metanavkastning och större CODtotal avlägsnat. Den största metanavkastningen och CODtotal avlägsnat är 0,167l/g CODtotal respektive 56.84% vid den högsta arbetstemperaturen 33.4°C med OLR 3.072g CODtotal/(l * dag) och HRT 4.2h. Energibalansen vid olika arbetstemperaturer visaratt det finns en stor skillnad i energibehov för uppvärmning och utbyte avenergi i form av biogas. För att minska klimatpåverkan och nå balans mellan input och output av energi måste energibehovet för uppvärmning reduceras. Energiåtervinning från utflöde till inflöde liksom drift av UASB vid låg temperatur är ämnen som kan studeras vid fortsatt arbete.

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Leachate from landfills is contaminated in many ways and per- and polyfluoroalkyl substances (PFAS)-contamination is one of them. Recent studies have demonstrated the environmental and human concerns of PFAS. Therefore, the treatment of leachate is important. One technique to reduce the PFAS concentration is by using aeration and foam fractionation. Hovgården is a landfill northeast of Uppsala, where previous measurements have shown high levels of PFAS in the leachate. Earlier small-scale experiments using aeration foam fractionation as a treatment technique for PFAS removal have been done successfully, but with upcoming requirements of PFAS concentrations there is a need to investigate whether an upscaling is possible or not. In this study, this has been investigated by pumping PFAS contaminated leachate from the landfill in to a 0.046 square metre plastic cylinder and aerated the leachate with an airflow of ten L min-1. A total of six experiments were conducted were the contact time and fraction of extracted foam was parameters that was varying. Four experiments were done with a contact time of ten min and foam fraction of five, ten, twenty and thirty percent and two experiments were made with a foam fraction of five percent and a contact time of twenty respectively thirty min. The average ΣPFAS removal, i.e., the percentage difference in ΣPFAS concentrations between the influent and effluent water in the different runs varied between 31 % and 66 %. The removal of long chained PFAS (≥C6) was higher than the removal of short chained PFAS(≤C5) even if all experiments did reduce the PFAS concentration. Carbon chains with a functional group containing a carboxylic acid is called perfluorocarboxylic acids (PFCA) and with a functional group containing a sulfonic acid is called perfluoroalkane sulfonic acids (PFSA). Precursors are PFAS that after a reaction degrades into PFCA and PFSA. The average removal efficiency of PFCA were 48 %, of PFSA 59 % and of precursors 78 %. The highest removal efficiency was discovered in the experiment with a 30-min contact time and five percent foam fraction with an average ΣPFAS removal of 58 % and an average Σlong chained PFAS removal of 92 %. The lowest removal efficiency was discovered in the experiment with a 10-min contact time and 20 percent foam fraction with an average ΣPFAS removal of 41 % and an average Σlong chained PFAS removal of 67 %. In conclusion a connection between increased contact time and increased removal efficiency was discovered but no clear connections between foam fraction and removal efficiency were found. However, it cannot be stated beyond reasonable doubt that the contact time is the decisive factor. Another conclusion is that the enrichment of short chained PFAS are higher in the water and a higher enrichment of long chained PFAS in the foam. In general, a higher inlet concentration of PFAS in the influent water resulted in a higher removal efficiency.

Wastewater treatment is energy intensive, with modern wastewater treatment processes consuming 0.6 kWh/m3 of water treated, half of which is required for aeration. Considering that wastewater contains approximately 2 kWh/m3 of energy and represents a reliable alternative water resource, capturing part of this energy and reclaiming the water would offset or even eliminate energy requirements for wastewater treatment and provide a means to augment traditional water supplies. Microbial electrochemical technology is a novel technology platform that uses bacteria capable of producing an electric current outside of the cell to recover energy from wastewater. These bacteria do not require oxygen to respire but instead use an insoluble electrode as their terminal electron acceptor. Two types of microbial electrochemical technologies were investigated in this dissertation: 1) a microbial fuel cell that produces electricity; and 2) a microbial electrolysis cell that produces hydrogen with the addition of external power. On their own, microbial electrochemical technologies do not achieve sufficiently high treatment levels. Innovative approaches that integrate microbial electrochemical technologies with emerging and established membrane-based treatment processes may improve the overall extent of wastewater treatment and reclaim treated water. Forward osmosis is an emerging low-energy membrane-based technology for seawater desalination. In forward osmosis water is transported across a semipermeable membrane driven by an osmotic gradient. The microbial osmotic fuel cell described in this dissertation integrates a microbial fuel cell with forward osmosis to achieve wastewater treatment, energy recovery and partial desalination. This system required no aeration and generated more power than conventional microbial fuel cells using ion exchange membranes by minimizing electrochemical losses. Membrane bioreactors incorporate semipermeable membranes within a biological wastewater treatment process. The anaerobic electrochemical membrane bioreactor described here integrates a microbial electrolysis cell with a membrane bioreactor using conductive hollow fiber membrane to produce hydrogen gas, treat wastewater and reclaim treated water. The energy recovered as hydrogen gas in this system was sufficient to offset all the electrical energy requirements for operation. The findings from these studies significantly improve the prospects for simultaneous wastewater treatment, energy recovery and water reclamation in a single reactor but challenges such as membrane biofouling and conversion of hydrogen to methane by methanogenesis require further study.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20814号 / 工博第4418号 / 新制||工||1686(附属図書館) / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 伊藤 禎彦, 教授 田中 宏明, 准教授 西村 文武 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM