| 1. |
- Baresel, Christian, et al.
(author)
-
Membrane Bioreactor Processes to Meet Todays and Future Municipal Sewage Treatment Requirements
- 2017
-
In: International Journal of Water and Wastewater Treatment. ; 3.2
-
Journal article (peer-reviewed)abstract
- Several municipal wastewater treatment plants (WWTPs) in Stockholm, Sweden, will within the near future face both an increased load due to a growing population as well as more stringent effluent quality requirements. The latter mainly regarding nutrients due to Sweden‘s commitment to the Baltic Sea Action Plan and the implementation of the European water framework directive (WFD). In addition, removal of emerging substances such as pharmaceutical residues, micro plastics and antibiotic resistance are gaining more attention since WWTP effluent is the most or one of the most significant sources of such loads to the environment [1-4]. Pharmaceutical residues and other emerging substances are generally not efficiently removed in conventional WWTPs [5]. The WFD has defined a list of prioritized substances including pesticides, biocides, flameretardants and metals [6], which already today require monitoring and treatment. Several other substances, including some pharmaceuticals, are on the ‘watch list’ of emerging pollutants that may be placed on the WFD priority list. Requirements for additional treatment, in larger WWTPs, for the reduction of some pharmaceutical residues and other micropollutants (MP) could thus be expected, also in other countries than Switzerland, where such a regulation is already in place. The potential negative effects on aquatic organisms, the aquatic food-web and higher organisms, as well as the risk of increased numbers of antibiotic resistant genes in bacteria, all present a threat to our environment, health and society [7-9]. Another increasing concern for wastewater treatment are emissions of greenhouse gases (GHGs). At WWTPs, special attention is given to nitrous oxide (N2O), which is a highly potent GHG (298 times more potent than carbon dioxide (CO2 ) [10]). At incomplete nitrification and denitrification N2O can be emitted, which may cause a significant negative overall environmental impact of the treatment process [11,12]. Even though regulations may earliest come in place in some years from now, many WWTPs actively work on reducing GHG emissions from wastewater treatment processes. Besides the requirements to increase capacity, improve treatment efficiency and reduce GHG emissions, many WWTPs also face the problem that they cannot expand spatially as they are located in densely populated areas or underground. New solutions for space-efficient, high-capacity and flexible municipal wastewater treatment processes are thus required. Stockholm Water and Waste Company (Stockholm Vatten och Avfall), Sweden’s largest water service organization, is directly facing the above problems of space limitation, increased capacity need and stricter effluent requirements at the Henriksdal WWTP in Stockholm. As a result, the existing conventional activated sludge process (CAS) will be converted to a Membrane Bioreactor (MBR), doubling the capacity by using existing process volumes only. The new process will be the world’s largest MBR facility with a capacity of 1.6 million PE (predicted load year 2040). MBRs combine the biological activated sludge process with membrane separation, which provide distinct advantages over the CAS. Advantages include a significantly better effluent (permeate) quality regarding particles, disinfection capabilities due to the membrane pore size, higher volumetric loading due to higher sludge concentrations in the biology, reduced footprint and process flexibility towards influent changes. Even the treatment of MP may be more efficient using MBRs compared to traditional treatment systems. This is partly explained by the fact that MP attached to particles can effectively be removed by filtration whereas dissolved MP can be degraded more effectively because of the higher biological activity in a MBR process. In addition, a more efficient polishing treatment compared to CAS can be achieved [11,13-18]. Drawbacks of the process are the high energy use for aeration and the use of cleaning chemicals in the filtration step to curb fouling and scaling on the membrane surface, which reduces the permeability of the membranes. MBRs have been used for a number of decades but only in the last decade, MBRs gained more attention for the treatment of both municipal and industrial wastewater. This is mainly due to a significant cost reduction of membranes and process development decreasing energy requirements [19-23]. The aim of this research work is to investigate the MBR technology concerning the overall holism and resource efficiency towards some of the most central treatment aspects including nutrient removal, removal of micropollutants and minimizing of GHG emissions. Through actual pilotscale experiments, the paper describes the performance of the studied system under various test periods defined to meet present and future requirements of the growing region of Stockholm, Sweden.
|
|
| 2. |
- Brännmark, Cecilia, et al.
(author)
-
FIND Stroke Recovery Study (FIND): rationale and protocol for a longitudinal observational cohort study of trajectories of recovery and biomarkers poststroke
- 2023
-
In: Bmj Open. - 2044-6055. ; 13:5
-
Journal article (peer-reviewed)abstract
- ntroduction Comprehensive studies mapping domain-specific trajectories of recovery after stroke and biomarkers reflecting these processes are scarce. We, therefore, initiated an exploratory prospective observational study of stroke cases with repeated evaluation, the FIND Stroke Recovery Study. We aim to capture trajectories of recovery from different impairments, including cognition, in combination with broad profiling of blood and imaging biomarkers of the recovery. Methods and analysis We recruit individuals with first-ever stroke at the stroke unit at the Sahlgrenska University Hospital, Sweden, to FIND. The inclusion started early 2018 and we aim to enrol minimum 500 patients. Neurological and cognitive impairments across multiple domains are assessed using validated clinical assessment methods, advanced neuroimaging is performed and blood samples for biomarker measuring (protein, RNA and DNA) at inclusion and follow-up visits at 3 months, 6 months, 1 year, 2 years and 5 years poststroke. At baseline and at each follow-up visit, we also register clinical variables known to influence outcomes such as prestroke functioning, stroke severity, acute interventions, rehabilitation, other treatments, socioeconomic status, infections (including COVID-19) and other comorbidities. Recurrent stroke and other major vascular events are identified continuously in national registers. Ethics and dissemination FIND composes a unique stroke cohort with detailed phenotyping, repetitive assessments of outcomes across multiple neurological and cognitive domains and patient-reported outcomes as well as blood and imaging biomarker profiling. Ethical approval for the FIND study has been obtained from the Regional Ethics Review Board in Gothenburg and the Swedish Ethics Review Board. The results of this exploratory study will provide novel data on the time course of recovery and biomarkers after stroke. The description of this protocol will inform the stroke research community of our ongoing study and facilitate comparisons with other data sets.
|
|
| 3. |
- Casati, Annalisa, 1988, et al.
(author)
-
Babble, exploring how digital technology can enhance children's understanding of multilingualism and its value
- 2016
-
In: Proceedings of SIDeR’16 – student interaction design research conference.
-
Conference paper (peer-reviewed)abstract
- An increasing part of the global population is migrating intodiverse locations and generating a wider amount of thirdculture children that face not only different habits but alsothe complexity of dealing with multiple languages on adaily basis. The focus of this research is to create a digitalapplication for multilingual children between ages 3 and 7.The concept developed is Babble, a digital game wherechildren collaborate using their different languages. Thispaper is a document of the development process, includingresearch and evaluation through three workshops, where 8children participated. The results presented will point atsome promise for using digital technology to develop adeepened appreciation of the children’s own languageskills.
|
|
| 4. |
- Cedersund, Gunnar, 1978-, et al.
(author)
-
Optimization in biology parameter estimation and the associated optimization problem
- 2016
-
In: Uncertainty in biology. - Cham : Springer. - 9783319212951 - 9783319212968 ; , s. 177-197
-
Book chapter (peer-reviewed)abstract
- Parameter estimation – the assignment of values to the parameters in a model – is an important and time-consuming task in computational biology. Recent computational and algorithmic developments have provided novel tools to improve this estimation step. One of these improvements concerns the optimization step, where the parameter space is explored to find interesting regions. In this chapter we review the parameter estimation problem, with a special emphasis on the associated optimization methods. In relation to this, we also provide concepts and tools to help you select the appropriate methodology for a specific scenario.
|
|
| 5. |
- Chistiakova, Tatiana, et al.
(author)
-
Binary classifiers applied to detect DO sensor faults during washing events
- 2015
-
In: Proc. 2nd IWA Conference on New Developments in IT & Water. - : IWA Publishing.
-
Conference paper (other academic/artistic)abstract
- In this paper, several classication techniques are applied for monitoring the status of DO sensors in wastewater treatment plants. In particular, DO sensors during washing events are studied and indication parameters from these events are used. The methods considered are the following: k-Nearest Neighbours, Radial Basis Function and Random Forest classiers. The result shows the comparison and the eligibility of the methods to detect a clogged DO-sensor.
|
|
| 6. |
- Johansson, Torbjörn, et al.
(author)
-
Datadrivna metoder för att detektera avvikande mätvärden inom dammsäkerhet
- 2020
-
Reports (other academic/artistic)abstract
- Vi gör en litteraturstudie av state of the art i dammsäkerhet och tar reda på vad som har gjorts i andra länder. Vi tittar även på teorier och metoder som inte ännu har använts i dammsäkerhet. Det är lätt att komma igång med datadriven analys med hjälp av färdiga verktygslådor som finns öppet tillgängliga. Vi diskuterar därför kring vanliga fallgropar vid dataanalys och hur man undviker dem. Mycket av den vetenskapliga litteraturen inom datadriven dammsäkerhet handlar om tillämpning av maskininlärningsmetoder. Den struntar ofta i förbehandling och antar att alla sensorer fungerar. Vi summerar resultat om förbehandling av sensordata och hur avvikelser kan detekteras, och ser att här finns ett gap i dammsäkerhetslitteraturen. Vi ser att väl förstådda och utredda metoder som PCA och PLS, tidsseriemodellering, SPC/MSPC och neurala nätverk är lämpliga för vidare studier. Med stöd av tiotals års erfarenhet av forskning och utveckling i datadrivna metoder ger vi rekommendationer för hur ett arbete för att implementera datadrivna metoder för att höja dammsäkerheten i Sverige skulle kunna utformas. Vi ser att datadrivna metoder för dammsäkerhet är redo att implementeras i Sverige, och bedömer att i kombination med väl utformad instrumentering och rätt givarplacering kan de bidra till väsentligt höjd dammsäkerhet.
|
|
| 7. |
- Kolsrud, Oscar, et al.
(author)
-
Measured and not estimated glomerular filtration rate should be used to assess renal function in heart transplant recipients.
- 2016
-
In: Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association. - : Oxford University Press (OUP). - 1460-2385. ; 31:7, s. 1182-9
-
Journal article (peer-reviewed)abstract
- In organ transplanted patients, impaired renal function is of major prognostic importance and influences therapeutic decisions. Therefore, monitoring of renal function with glomerular filtration rate (GFR) is of importance, both before and after heart transplantation (HTx). The GFR can be measured directly (mGFR) or estimated (eGFR) with equations based on circulating creatinine or cystatin C levels. However, these equations have not been thoroughly validated in the HTx population.
|
|
| 8. |
- Kolsrud, Oscar, et al.
(author)
-
Renal function and outcome after heart transplantation
- 2018
-
In: Journal of Thoracic and Cardiovascular Surgery. - : Elsevier BV. - 0022-5223. ; 155:4
-
Journal article (peer-reviewed)abstract
- Objectives: To investigate whether measured glomerular filtration rate (mGFR) is a risk factor for death and/or end-stage renal disease (ESRD) after heart transplantation (HTx). Methods: All adult patients (n = 416) who underwent HTx between 1988 and 2010 were included. mGFR was performed both preoperatively and postoperatively as annual follow-up. Eight patients received a concomitant kidney transplant (KTx), and 15 underwent late KTx due to chronic renal failure after HTx. Results: The mean drop in mGFR compared with the preoperative value was 12% during the first year after HTx. Preoperative mGFR was not predictive of mortality or ESRD. Older or the use of a ventricular assist device (VAD) were preoperative predictors of death. Long-term survival was significantly worse in the patients who experienced a >25% decrease in mGFR during the first year after transplantation. The need for acute postoperative renal replacement therapy (RRT) was associated with impaired survival but did not predict ESRD among survivors. On multivariable analyses, previous heart surgery, preoperative VAD, and a lower mGFR were all predictors of RRT. In the most recent period, death without previous ESRD was lower, and the only preoperative factors associated with ESRD by multivariable analyses were mechanical ventilation and diabetes mellitus. Conclusions: Pretransplantation mGFR was not predictive of mortality or ESRD after HTx, but necessitated simultaneous or late-stage KTx in this selected population of patients. However, patients with a decrease in >25% mGFR during the first year post-transplantation, as well as early postoperative dialysis-dependent acute renal dysfunction, had a poor prognosis. We suggest that patients with severely impaired kidney function, irrespective of pretransplantation renal function, still should be considered for HTx, but also encourage careful interpretation of our results given the selection bias involved in this population.
|
|
| 9. |
- Larsson, Sylvia, et al.
(author)
-
Cassava Stem Powder as an Additive in Biomass Fuel Pellet Production
- 2015
-
In: Energy and Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 29, s. 5902-5908
-
Journal article (peer-reviewed)abstract
- In biomass fuel pelletizing, some raw materials with less favorable binding properties require a binding enhancing additive for enhancing required pellet quality. Starch is commonly used as a binder in industrial fuel pelletizing but is a refined product that adds substantially to pellet production costs. In this study, finely milled cassava stems, a starch-rich, cheap, and underutilized byproduct from food production, were used and compared to refined starch as an additive in biofuel pellet production. The evaluation was performed in an experimental design with the factors cassava stem/starch content, moisture content, and material temperature. Measured responses were pellet bulk density, mechanical durability, amount of fines, pelletizer motor current, coefficient of variance for pelletizer motor current, CVA (a measure of process stability), pellet temperature, die temperature, and pellet moisture. Each response was modeled by multiple linear regression (MLR). Cassava stem addition gave similar effects as starch addition by increasing pellet durability and reducing the amount of fines, particularly at low moisture contents (MC ∼ 11%). The highest pellet durability in the study was achieved at a low moisture content (11% MC) when using cassava stem as an additive. Combustion properties of the pellets were determined in a residential pellet burner. Low emissions and no ash fouling were obtained for both of the additive types. In conclusion, cassava stem powder is a good additive substitute for refined starch to increase fuel pellet quality.
|
|
| 10. |
- Lindblom, Erik U., et al.
(author)
-
Comparison of guideline- and model-based WWTP design for uncertain influent conditions
- 2023
-
In: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 87:1, s. 218-227
-
Journal article (peer-reviewed)abstract
- In this study, two methods for wastewater treatment plant (WWTP) dimensioning were compared: (1) a traditional guideline-based approach, and (2) a mechanistic model-based approach. The design outputs depended on uncertainties in correlated influent concentrations, which emphasises the importance of uncertainty analysis. The results showed that model-based design could simplify and reduce the time required for uncertainty and sensitivity analysis compared to a conventional design approach, in which the equations are solved manually and iteratively. A benefit of the conventional design approach was the simple interpretation of which factors limited the design capacity. In the end, this study shows the potential, as well as the need for, model-based design of WWTPs.
|
|
