Which State’s law should determine if a dispute is amenable to out-of-court settlement and consequently whether a dispute is arbitrable under Swedish law? Some legal scholars reason that general principles of private international law should solve the question as a conflict-of-laws issue, while others believe that Swedish mandatory law should apply directly. The Swedish Arbitration Act is unclear and both solutions find support in contradictory case law. It is thus not only debatable what the law should be, but also what it is. The Supreme Court recently had an opportunity to clarify this point of law (NJA 2012 s. 790), but left us with a ruling that is reminiscent of the words by the Swedish poet Esaias Tegnér (own translation): What you cannot say clearly, you do not know; with thought the word is conceived on the lips of man; words unclearly spoken are unclearly thought. This paper attempts to bring clarity to what the law is (de lege lata), as well as a proposition to what the law should be (de lege ferenda). The suggested solution aims to be consistent with a number of concepts. These include; the underlying rationale of non-arbitrability, the obligations under the New York Convention, general principles of private international law, international trends and Swedish law in general. First, it is held that non-arbitrability serves to protect the exclusive jurisdiction of the State’s own courts. There is therefore no need to investigate whether a dispute is amenable to out-of-court settlement, or apply the doctrine of non-arbitrability, in international disputes with little connection to Sweden. In these cases, there is no risk of collision with the exclusive jurisdiction of Swedish courts. Second, the requirement that disputes must be amenable to out-of-court-settlement should be interpreted in light of its context. No duty exists to consider foreign concepts under general principles of private international law. For this reason, and others presented in this paper, the question of whether the parties can settle their dispute by agreement should be examined under Swedish mandatory law. This should only be examined when there is a collision between the exclusive jurisdiction of Swedish courts and a tribunal. This solution is in line with the international trend of in favorem arbitrandum and the New York Convention. It is also the only practical solution since it would be unnecessarily complicated for Swedish courts to ex officio determine the content of foreign law. This would prolong the process and limit arbitration’s effectiveness.

This project utilizes hydrocyclones in wastewater treatment to select for heavier solids, and has been used before in multiple small-scale systems. This is the first implementation of hydrocyclones in a full-scale plant for the purpose of increased settleability, while also achieving enhanced biological phosphorus removal without the use of an anaerobic selector. Hydrocyclones receive mixed liquor tangentially and separate light solids from more dense solids through their tapered shape, increasing the velocity of liquid as it moves downward and allowing for selection of a certain solids fraction. The hydrocyclones receive flow from the waste stream, selecting for dense solids to recycle through the process while light solids are wasted, creating a balance of granules and flocs with superior settling characteristics in which phosphorus is removed through phosphorus accumulating organisms (PAO). This project was implemented at a wastewater treatment plant rated at 20 MGD utilizing a 4-stage Bardenpho configuration with an IFAS system. This plant routinely experienced moderate settleability issues with an average SVI of 141 and a 90th percentile SVI of 179. Over time data was collected to characterize settleability and activity of PAO, GAO, and filaments. Using an external selector to achieve biological phosphorus is significant in that most wastewater treatment plants cannot do this without the use of an anaerobic selector. This has the potential to apply external selectors to existing infrastructure throughout plants worldwide to achieve not only biological phosphorus removal, but also improved settleability with a very minor capital investment. / Master of Science

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Nutrients and cations have significant effect on activated sludge characteristics and therefore effect the efficiency of whole processes. To determine the properties in phosphorus deficient medium and the effect of calcium ions two reactor sets with two different phosphorus concentration (C/N/P=100/5/0.05 and C/N/P=100/5/1), three different concentrations of calcium (0.5, 5, 15 meq/L) were operated with 8 days of sludge residence time and an effective volume of 2 L. Results showed amount and composition of EPS was dependent on calcium and phosphorus concentrations. Except for the highest calcium concentration, increase in phosphorus concentration resulted in increase in total EPS production. Under phosphorus deficient conditions, calcium ions stimulated the production of carbohydrate type polymers and viscous bulking was observed. However, the increase in phosphorus concentration led to increase in protein type polymer production and bulking condition was cured. Addition of calcium ions increased conductivity in both cases, but increase in phosphorus concentration caused decrease in conductivity. Increase in phosphorus concentration had improved settleability, dewaterability and rheology of sludge. Moreover, effluent turbidity was decreased and COD removal efficiency was recorded as greater than 95 % for all calcium concentrations under phosphorus sufficient conditions. Microscopic analyses showed that under phosphorus deficient conditions flocs were weak, dispersed and nonresistant. Increase in phosphorus concentration resulted in improvement of floc structure. Same Enterobacter and Citrobacter species were identified at all calcium concentrations under phosphorus deficient conditions. Yet, under phosphorus sufficient conditions different species were identified in control reactor as compared to 5 meq/L and 15 meq/L concentrations.

Bioflocculation happens naturally and microorganisms aggregate into flocs during wastewater treatment. It is critical to understand the mechanisms of bioflocculation and its impact on the following solid/liquid separation process since seperation by settling is one of the key aspects that determine the efficiency and the overall economy of activated sludge systems. Bioflocculation occurs via extracellular polymeric substances (EPS) and cations by creating a matrix to hold various floc components together so the cations become an important part of the floc structure. The main objective of this study is to investigate the effects of monovalent cations specifically potassium and sodium (K and Na) on the bioflocculation, settleability and dewaterability of activated sludge. The particular aim is to grow the mixed culture microorganisms in the presence of specific cation so that the effect of cation on the stimulation of EPS production can be seen. In order to achieve this aim, semi-continuous reactors were separately operated at concentrations of 5, 10, and 20 meq/L of each cation with mixed culture bacteria and fed with synthetic feed medium representing influent to the activated sludge systems. Also, a control reactor at low cation dose was operated for each reactor set. The effective volume of the reactors was 2 L with 8 days of sludge residence time (SRT) and pH was kept at 7.7&plusmn / 0.3. The activated sludge reactors were operated until the reactors reached steady state and then related analyses were conducted. It was found that addition of potassium and sodium ions at increasing concentrations resulted in increase in total polymer concentration. However, potassium ions promoted the synthesis of both polysaccharide and protein type polymers whereas sodium ions tended to stimulate production of protein type polymers and had an affinity to bind more protein within the floc structure. Sodium sludges had lower hydrophobicity and higher surface charges, so sodium ions led to deterioration in flocculation of sludges. Addition of both these ions decreased the dewaterability, sodium ions had more detrimental effect on dewaterability of sludges compared to potassium ions. The examination of data related to settleability showed that potassium ions led to no drastic deterioration in settling characteristics of the activated sludge but the addition of sodium ions deteriorated the settleability. In addition, it was seen that while the addition of potassium ions to the feed led to a decrease in viscosity, increase in sodium concentration correlated with an increase in viscosity. Finally, the comparison of chemical oxygen demand (COD) removal efficiency of these cations showed that sodium is more efficient in COD removal.

Bioflocculation, which can be defined as aggregation of bacterial flocs, has important implications on the physical characteristics of sludge. It is especially critical to settling and dewatering systems which impacts the overall economy of the process greatly. One of the most common problems in activated sludge systems to negatively influence the settleability is sludge bulking which can be defined as non-settling situation of microbial mass. The first objective of this research is to investigate the effect of calcium ion on sludge bulking in a phosphorus deficient medium and the second objective is to improve the settling, dewatering, and pumping of activated sludge by adjusting the calcium (Ca) ion concentration of the feed. For this purpose, 7 semi-continuous laboratory scale activated sludge reactors were operated with a mixed aerobic culture. The reactors had 8 days of sludge residence time and aerated with air pumps to provide a dissolved oxygen concentration of at least 3 mg/L. All the analyses were conducted after the reactors reached steady state condition. In the first part of the research, the effect of strictly phosphorus-limited medium on bulking of activated sludge was studied at different calcium ion concentration. Three reactors were set up having 5, 10 and 20 meq/L calcium concentrations. From the results it was observed that, phosphorus deficiency caused viscous bulking independent from the calcium ion concentration. It was found out that bulking of activated sludges due to phosphorus deficiency could be cured by the addition of phosphorus. Furhermore, microorganisms starved for phosphorus, seemed to accumulate polyphosphate granules when they were exposed to a phosphorus source. In the second part of the study, the effect of calcium ion on physical, chemical and surface chemical properties of activated sludge was investigated at 4 different concentrations (0.27, 5, 10 and 20 meq/L) under sufficient phosphorus concentration. Calcium addition resulted in significant changes in the quantity and quality of extracellular polymeric substances (EPS). Total EPS increased depending on the calcium concentration. Carbohydrate content of EPS dominated over the protein content for calcium concentration of 5 meq/L and above. The amount of calcium ions incorporated into the sludge floc matrix also increased with the dose of calcium added. Settleability and dewaterability of sludge improved significantly at 5 meq/L dose of calcium. However, settleability did not change any further with increasing calcium dose, whereas dewaterability increased for all increasing calcium concentrations. Sludge viscosity also decreased considerably at 5 meq/L concentration indicating better pumpability but it did not change further above 10 meq/L calcium addition.