Treatment of oily wastewater by ultrafiltration: The effect of different operating and solution conditions

In many industries, such as petroleum production, and the petrochemical, metal, food and cosmetics industries, wastewaters containing an emulsion of oil in water are often produced. The emulsions consist of water (up to 90%), oils (mineral, animal, vegetable and synthetic), surfactants and other contaminates. In view of its toxic nature and its deleterious effects on the surrounding environment (soil, water) such wastewater needs to be treated before release into natural water ways. Membrane-based processes have successfully been applied in industrial applications and are considered as possible candidates for the treatment of oily wastewaters. Easy operation, lower cost, and in some cases, the ability to reduce contaminants below existing pollution limits are the main advantages of these systems. The main drawback of membranes is flux decline due tofouling and concentration polarisation. The complexity of oil-containing systems demands complementary studies on issues related to the mitigation of fouling and concentration polarisation in membranebased ultrafiltration. In this thesis the effect of different operating conditions (factors) on ultrafiltration of oily water is studied. Important factors are normally correlated and, therefore, their effect should be studied simultaneously. This work uses a novel approach to study different operating conditions, like pressure, flow velocity, and temperature, and solution properties, like oil concentration (cutting oil, diesel, kerosene), pH, and salt concentration (CaCl2 and NaCl)) in the ultrafiltration of oily water, simultaneously and in a systematic way using an experimental design approach. A hypothesis is developed to describe the interaction between the oil drops, salt and the membrane surface. The optimum conditions for ultrafiltration and the contribution of each factor in the ultrafiltration of oily water are evaluated. It is found that the effect on permeate flux of the various factors studied strongly depended on the type of oil, the type of membrane and the amount of salts. The thesis demonstrates that a system containing oil is very complex, and that fouling and flux decline can be observed even at very low pressures. This means that only the weak form of the critical flux exists for such systems. The cleaning of the fouled membranes and the influence of different parameters (flow velocity, temperature, time, pressure, and chemical concentration (SDS, NaOH)) were evaluated in this study. It was observed that fouling, and consequently cleaning, behaved differently for the studied membranes. Of the membranes studied, the membrane with the lowest propensity for fouling and the most easily cleaned was the regenerated cellulose membrane (C100H). In order to get more information about the interaction between the membrane and the components of the emulsion, a streaming potential study was performed on the membrane. The experiments were carried out at different pH and oil concentration. It was seen that oily water changed the surface charge of the membrane significantly. The surface charge and the streaming potential during different stages of filtration were measured and analysed being a new method for fouling of oil in this thesis. The surface charge varied in different stages of filtration. It was found that the surface charge of a cleaned membrane was not the same as initially; however, the permeability was equal to that of a virgin membrane. The effect of filtration mode was studied by performing the filtration in both cross-flow and deadend mode. The effect of salt on performance was considered in both studies. It was found that salt decreased the permeate flux even at low concentration. To test the effect of hydrophilicity change, the commercial membranes used in this thesis were modified by grafting (PNIPAAm) on their surfaces. A new technique (corona treatment) was used for this modification. The effect of modification on permeate flux and retention was evaluated. The modified membranes changed their pore size around 33oC resulting in different retention and permeability. The obtained results in this thesis can be applied to optimise the operation of a membrane plant under normal or shock conditions or to modify the process such that it becomes more efficient or effective.

Periprocedural prognostic factors in coronary interventions – retrospective studies

Background: Approximately 11,000 revascularization procedures, either percutaneous coronary interventions (PCI) or coronary artery bypass grafting surgery (CABG), are performed yearly in Finland for coronary artery disease. Periprocedural risk factors for mortality and morbidity as well as long-term outcome have been extensively studied in general populations undergoing revascularization. Treatment choice between PCI and CABG in many high risk groups and risk-stratification, however, needs clarification and there is still room for improvement in periprocedural outcomes. Materials and methods: Cohorts of patients from Finnish hospitals revascularized between 2001 and 2011 were retrospectively analyzed. Patient records were reviewed for baseline variables and postprocedural outcomes (stroke, myocardial infarction, quality of life measured by the EQ-5D –questionnaire, repeat revascularization, bleeding episodes). Data on date and mode of death was acquired from Statistics Finland. Statistical analysis was performed to identify predictors of adverse events and compare procedures. Results: Postoperative administration of blood products (red blood cells, fresh frozen plasma, platelets) after isolated CABG independently and dose-dependently increases the risk of stroke. Patients 80 years or older who underwent CABG had better survival at 5 years compared to those who underwent PCI. After adjusting for baseline differences survival was similar. Patients on oral anticoagulation (OAC) for atrial fibrillation (AF) treated with CABG had better survival and overall outcome at 3 years compared to PCI patients. There was no difference in incidence of stroke or bleeding episodes. Differences in outcome remained significant after adjusting for propensity score. Lower health-related quality of life (HRQOL) scores as measured by the visual analogue scale (VAS) of the EQ-5D questionnaire at 6 months after CABG predicted later major adverse cardiac and cerebrovascular events (MACCE). Deteriorating function and VAS scores between 0 and 6 months on the EQ-5D also independently predicted later MACCE. Conclusions: Administration of blood products can increase the risk of stroke after CABG and liberal use of transfusions should be avoided. In the frail subpopulations of patients on OAC and octogenarians CABG appears to offer superior long-term outcome as compared to PCI. Deteriorating HRQOL scores predict later adverse events after CABG. Keywords: percutaneous coronary intervention, coronary artery bypass grafting, age over 80, transfusion, anticoagulants, coronary artery disease, health-related quality of life, outcome.

Primary and Revision Hip Replacement. A University Hospital Database and Registry Study

Large-headed total hip arthroplasty (THA) and hip resurfacing arthroplasty (HRA) with metal-on-metal (MoM) bearings became popular during the last decade. Recently, it has become evident that the large-head MoM hip implants are associated with increased revision rates despite their theoretical advantages. The purpose of this study was to evaluate the early results of primary MoM hip replacements and of acetabular revisions. I analyzed retrospectively the results of four MoM implant designs and the survival rate of acetabular revisions with impaction bone grafting, as documented in the Turku University Hospital database. Further, I evaluated the correlation between femoral head size and dislocation rate, and used the Finnish Arthroplasty Register data to compare the survival of three large-head MoM THAs to analogous HRAs. The early results for the Magnum M2A–ReCap THA were good. A larger head size decreased the risk of dislocation. Articular surface replacement (ASR) THA yielded inferior results compared to analogous HRA. For two other designs the results were similar. The R3–Synergy THA yielded inferior results compared to the reference implants. The survival of acetabular reconstructions with impaction bone grafting was inferior compared to previous reports. In conclusion, the early results of the Biomet ReCap–Magnum design were promising, and large head sizes decreased the dislocation rate. The survival of different MoM hip implant designs varied. The survival of new designs and techniques may be inferior to those reported by the clinics where implants are developed. An important caveat is that early promising results of new devices may rapidly worsen. New implants need to be introduced in a controlled fashion to the market; here, arthroplasty registers are a valuable tool that needs to be used.

Functionalisation of spruce O-acetyl-galactoglucomannans for barrier and composite applications

The increasing use of energy, food, and materials by the growing population in the world is leading to the situation where alternative solutions from renewable carbon resources are sought after. The growing use of plastics depends on the raw-oil production while oil refining are politically governed and required for the polymer manufacturing is not sustainable in terms of carbon footprint. The amount of packaging is also increasing. Packaging is not only utilising cardboard and paper, but also plastics. The synthetic petroleum-derived plastics and inner-coatings in food packaging can be substituted with polymeric material from the renewable resources. The trees in Finnish forests constitute a huge resource, which ought to be utilised more effectively than it is today. One underutilised component of the forests is the wood-derived hemicelluloses, although Spruce Oacetyl-galactoglucomannans (GGMs) have previously shown high potential for material applications and can be recovered in large scale. Hemicelluloses are hydrophilic in their native state, which restrains the use of them for food packaging as non-dry item. To cope with this challenge, we intended to make GGMs more hydrophobic or amphiphilic by chemical grafting and consequently with the focus of using them for barrier applications. Methods of esterification with anhydrides and cationic etherification with a trimethyl ammonium moiety were established. A method of controlled synthesis to obtain the desired properties by the means of altering temperature, reaction time, the quantity of the reagent, and even the solvent for purification of the products was developed. Numerous analytical tools, such as NMR, FTIR, SEC-MALLS/RI, MALDI-TOF-MS, RP-HPLC and polyelectrolyte titration were used to evaluate the products from different perspectives and to acquire parallel proofs of their chemical structure. Modified GGMs with different degree of substitution and the correlating level of hydrophobicity was applied as coatings on cartonboard and on nanofibrillated cellulose-GGM films to exhibit barrier functionality. The water dispersibility in processing was maintained with GGM esters with low DS. The use of chemically functionalised GGM was evaluated for the use as barriers against water, oxygen and grease for the food packaging purposes. The results show undoubtedly that GGM derivatives exhibit high potential to function as a barrier material in food packaging.