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Microalgae have been in the center of research for several years due to their high production rates. The use of fresh-water algae in the production of biofuels coupled with wastewater treatment has become a topic of modern research. While most algal farming is performed in warm and sunny climate, this project focused on naturally occurring microalgae in Northern Sweden and their ability to reclaim wastewater and produce lipids. The four microalgae Chlorococcum sp. (MC1), Scotiellopsis reticulata (UFA-2), Coelastrella sp. (3-4) and Chlorella vulgaris (13-1) were grown under mixotrophic conditions in municipal wastewater (MWW), pulp and paper wastewater (PnP) and mixtures of both. Except of UFA-2, I found the growth of the tested species to be limited in pure PnP, however, mixtures of PnP and MWW were suitable for algal growth. The removal rates of total nitrogen achieved the goals regulated by the Swedish government for wastewater reclamation. Phosphorus, of which maximal levels according the Swedish regulations need to be below 0.5 mg/L, was efficiently removed by the strain 3-4 in PnP and in MWW + PnP (ratio 3+1) as well as by the strain 13-1 in MWW + PnP (ratio 3+1). The tested microalgae are therefore appropriate candidates to be used in sustainable wastewater treatment. The algal biomass composition was determined with the help of Fourier-transform infrared spectroscopy and an increase in the spectra for biomass grown in wastewaters within the fingerprint region (800 – 1800 cm-1) was observed. From this, I conclude that the lipid content was elevated in the biomass received after growth in PnP and all mixtures of MWW and PnP compared to the in BG11 grown biomass, which acts as a control group. A quantitative lipid analysis performed on the biomass of the strains UFA-2 and 3-4 confirmed higher lipid amounts after growth in PnP wastewater compared to growth in BG11. These findings show that the examined microalgae might have the potential to be used as a potential feedstock for biofuel productions after cultivation in local wastewaters.

Yes / Wastewater treatment is an energy-intensive operation. Energy consumption is forecast to increase by 60% in the forthcoming decade due to tightened legislation surrounding the discharge of final effluent to watercourses. Treatment plants rely on the time-consuming and unreliable biochemical oxygen demand to assess the quality of final effluent, leading to process inefficiencies. Here, the authors show that fluorescence spectroscopy is a robust technique for real-time monitoring of changes in effluent quality. Three portable fluorimeters were installed for one month at the final effluent discharge point of a large municipal wastewater treatment plant. The authors show that organic matter composition of the wastewater varies diurnally depending on the flow rate and antecedent rainfall. High fluorescence intensity and ammonia are attributed to sewage sludge liquor, which is regularly discharged to the treatment plant. Moreover, elevated fluorescence intensities were recorded as a result of process failure following a power outage. The study shows that online fluorescence analysis is capable of detecting both minor changes in effluent quality and issues with treatment process performance. / European Commission Framework Programme 7, Marie Curie IEF (PIEF-GA-2012-329962) and the Core Program, ANCS (PN 16.40.01.01).

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<p> The Biological Aerated Filter is a novel biological wastewater treatrrent process consisting of.an activated sludge zone followed by an unstratified sand filter for solids separation. Three evaluation studies of the BAF to date have yielded results indicating low solids production or possibly total oxidation. On the basis of these studies, Tymflo Process Limited, the patent holding corrpany, clairred up to 50% cost savings for wastewater.treabrent as there would be no excess biological solids produced, and therefore no sludge disposal costs. The object of this report was to evaluate the BAF capabilities to treat degritted municipal sewage with respect to the above claims. Two pilot scale BAF units were operated at the Canada Centre for Inland Waters continuously for 97 days treating degritted Burlington Skyway sewage at various operating conditions. The conclusions of the tests are that the BAF cannot be operated as a total solids retention system treating degritted nnmicipal sewage on a 24 hour cycle at a 12 hour hydraulic detention ti.Ile. The inert fraction of the influent is retained in the system resulting in high mixed liquor concentrations which overload the filter thereby decreasing treatrrent tine. The system is capable of 88% CDD rerroval, essentially corrplete nitrification and 97% SS rerroval. The system yields are in the order of 0.24 gm MLVSS/grn COD rercoved at organic loadings of approximately 0.08 gm COD removed/gm MLVSS day. </p> / Thesis / Master of Engineering (MEngr)

PFAS (per- and polyfluoroalkyl substances) are a large group of substances that are used in a large variety of products because of their unique water and dirt repellent properties. The substances are extremely persistent and can spread over large distances in groundwater, surface water, and in the air, which makes them an environmental and a health concern. A significant pathway of PFAS into the environment is through wastewater, where the usage of consumer products containing PFAS contribute to the emissions. The project was performed by analysing data of PFAS concentrations in wastewater and sludge sampled continuously during 2022 at Uddebo wastewater treatment plant (WWTP) in Luleå municipality. The aim was to evaluate the composition of PFAS compounds and their concentrations in wastewater and sludge and compare with other municipalities, to analyse how PFAS concentrations change during the existing wastewater treatment process, and to suggest strategies for future treatment of PFAS in wastewater.  No significant change of the PFAS content in wastewater could be observed throughout the treatment process in Uddebo WWTP. Evaluation of the PFAS composition showed that PFOS was the most abundant substance in both water and sludge. Over the year some variations in the total PFAS concentration could be seen, which coincided with increased water flow during the snowmelt period and an operational disturbance at the treatment plant. The variations of the total PFAS concentrations in wastewater over the year were mainly caused by PFBA, PFOS and 6:2 FTS. Analysis of total oxidizable precursors in the wastewater showed that substances that can transform into more persistent PFAS are present in the incoming water to the plant to a large extent. The pilot plant designed for treatment of pharmaceuticals, including ozonation and a granular activated carbon filter, did not result in any separation of PFAS from the water. An assessment of the contribution of PFAS from landfill leachate showed that it constitutes a significant share of the total PFAS content in wastewater. Compared with the content of PFAS in other Swedish WWTPs the total concentrations in wastewater at Uddebo WWTP was among the highest of five compared municipalities, while Luleå had the lowest PFAS concentrations in sludge among two compared municipalities.  The comparison between municipalities was limited by large differences in sampling frequency and performed analyses between the municipalities. Standardised analyses, additional background information, and more detailed statistical analyses are necessary to be able to make this type of comparison more informative. The occurrence of PFOS, which have been globally banned since 2009, shows that restrictions of the usage of PFAS must be combined with treatment of contaminated media to reduce the concentrations of PFAS in the environment. Development of PFAS degradation techniques is vital to remove PFAS from circulation. The difficulties of treating large amounts of water with low concentrations motivates investigations concerning if treatment of smaller water flows with higher PFAS concentrations is a better alternative than implementing treatment of the total amount of water that reaches the WWTP.

Harmful algal blooms (HABs) can be detrimental to ecosystems, human health, and economies. The low levels of phosphorus remaining in the effluent of municipal wastewater treatment plants can contribute to HAB formation. To achieve more complete phosphorus removal, an effluent treatment method has been proposed that uses phosphorus-deprived, filamentous microalgae to quickly assimilate soluble phosphorus to low concentrations. This study investigated two parameters that influence the feasibility of such a system: (1) the biomass growth productivity of algal cultures during the phosphorus deprivation period and (2) the correlation between the duration of this period and the phosphorus uptake rate by the biomass when contacted with the water to be treated. A single strain of filamentous algae, Tribonema minus, was used. Two experiments lasting 8-9 days compared the biomass productivity of cultures of T. minus grown in phosphorus-replete and -deplete media. While no significant difference in productivity was observed between treatments, further studies should be done to confirm this finding. In addition, 39 uptake contact experiments were conducted. The soluble phosphorus uptake rate was measured for algae deprived of phosphorus for 0 to 12 days of growth. The highest observed uptake rate was 3.83 mg P/g VSS-h, during the first three hours of contact, by biomass that had been phosphorus-deprived for 12 days. The correlation between phosphorus deprivation duration and 3-h uptake rate was 0.34 mg P/g VSS-h per day of deprivation (R2 = 0.81). Additional development efforts seem justified based on these results.

As wastewater treatment plants transition to water resource recovery facilities, the need for improved control and consequently supervision increases. Despite the large volume of research that has been performed on this topic, the use in industry is scarce. Practical implementation is challenging due to the nature of the process, and a lack of standardisation in the research results in uncertainty as to the state of the art. This is one of the main challenges identified.  Experimental work is performed using the Benchmark Simulation Model No. 1 to identify monitoring requirements and evaluate the performance of univariate fault detection methods. For the former, residual based process fault signatures are used to determine minimal sensor requirements based on detectability and isolability goals. Sensor faults are the focus of the latter issue, using the Shewhart, cumulative sum, and exponentially weighted moving average control charts to detect bias and drift faults in a controlled variable sensor.  The use of a standard model and known fault detection methods is useful to establish a baseline for future work. Given the lack of standardised use in industry this is considered critical. Both proposed methods emphasise ease of visualisation which is beneficial for industrial implementation.

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