The purpose of this study is to evaluate the convenience and effectiveness of using a disc filter to treat washing water from the sand filters at Sundet wastewater treatment plant. The disc filter is used aiming for the reduction of suspended solids and phosphorus. The study was divided in two main experimental stages. During the first stage laboratory jar-tests were performed in order to identify which flocculation aid was more suitable, this was further on used to improve the water treatment. Based on the laboratory trials results, two different polymers (1 and 2) were chosen to be tested at pilot scale. The second stage involved the pilot filter operation itself; this period was as well divided in two sub-stages where filter cloths with two different pore openings were tested. During the first sub-stage the pilot operated with an 18 μm pore opening filters cloth and both polymers. At the end of the first half polymer 1 showed to be more efficient and so it was further used throughout the second sub-stage in combination with a 10μm pore opening filter cloth. As from theoretical knowledge the phosphorus and suspended solid removal were expected to be between 75% and 90%, results which were achieved during both laboratory trials and pilot filter. The best results were observed with the 10μm pore opening filter cloth and polymer 1. Also, additional results from pilot trials performed at Sundet after the study period are presented.

The costs of cleaning fine coal are substantially higher than those of cleaning coarse coal. Therefore, many many coal companies in the U.S. choose to discard fine coal (150 micron x 0) by means of 6-inch diameter hydrocyclones. The cyclone overflows are stored in fine coal impoundments, which create environmental concerns and represent loss of valuable national resources. The major component of the high costs of cleaning fine coal is associated with the difficulty in fine coal dewatering. Therefore, the availability of efficient of fine coal dewatering methods will greatly benefit companies. In the present study, three different novel dewatering aids have been tested. These include Reagents W (RW), Reagent U (RU), and Reagent V (RV). These reagents are designed to increase the contact angles of the coal samples to be dewatered, which should help decrease the Laplace pressure of the water trapped in filter cake and, hence, increase dewatering rate. They were tested on i) the fresh coal samples from Consolidation Coal Corporation's Buchanan Preparation Plant, ii) a composite drill core sample from the Smith Branch Impoundment, Pinnacle Mine Mining Company, and iii) a blend of coals from the Smith Branch Impoundment, thickener underflow, and thickener feed. The coal samples were used initially for laboratory-scale tests using a 2.5-inch diameter Buchner vacuum filter. The results showed that the use of the novel dewatering aids can reduce the cake moisture up to 50% over what can be achieved without using any dewatering aid. The use of the dewatering aids also increased the kinetics of dewatering by up to 6 times, as measured by cake formation times. On the basis of the laboratory test results, pilot-scale continuous vacuum filtration tests were conducted using a 2-feet diameter Peterson vacuum disc filter. The cake moistures obtained in the pilot-scale test work were similar to those obtained in the laboratory tests, while the fast dewatering kinetics observed in the laboratory tests was manifested as higher throughput. It was found that high-shear agitation is essential for achieving low cake moistures and high throughput. / Master of Science

Ett avloppsvatten innehåller olika föroreningar som påverkar recipientens vattenkvalitet. En förorening somreningsverken inte är optimerade för att reducera är mikroorganismer, som i recipienten påverkar bland annatbadvattenkvalitén. Syftet med examensarbetet var att ta reda på hur utvalda processteg i ett reningsverkpåverkar utgående halter av mikroorganismer, hur utsläppen av mikroorganismer kan övervakas och hur mikroorganismernapåverkar recipientens badvattenkvalitet. Examensarbetet har uppfyllt syftet genom att undersökahur biologiska reningssteg reducerar indikatororganismerna E.coli och intestinala enterokocker jämfört medslutreningsalternativen kontinuerligt sandfilter samt skivfilter. Provtagning genomfördes på två reningsverk ochresultatet analyserades för att besvara frågan. Andra kvalitetsparametrar i avloppsvattnet samt flöde, lufttemperaturoch nederbörd har jämförts med utgående koncentration av indikatororganismerna från reningsverk föratt undersöka om det finns några samband som går att använda för att uppskatta det mikrobiologiska utsläppet.För undersökningen har de statistiska metoderna Kendalls Tau och Partial Least Squares använts. En litteraturstudiepå hur implementering av läkemedelsrening med ozon kan desinficera avloppsvattnet, vilken doseringsom krävs och vad den bör baseras på har genomförts. Efter avloppsutsläpp i en recipient sprids mikroorganismernamed vattnets strömmar och mikroorganismerna dör normalt av med tiden. Denna avdödandeprocesskan beskrivas med en ekvation av första ordningens kinetik. Ekvationens känslighet för variation i variablernasolinstrålning, temperatur, siktdjup och tid har undersökts. Ekvationen har även använts för en fallstudie av avloppsutsläppvid bräddning och hur det påverkar en badplats nedströms. För fallstudien fanns information omflödestid, utspädning och nedbrytningsvariablerna att tillgå. Undersökningen visar att biologisk rening med biobädd reducerar indikatororganismerna effektivast av de undersöktareningsstegen. Sandfiltrets reduktionsförmåga var god men skivfiltret presterade sämre. Från provtagningenframkom också att koncentrationen av E.coli är konsekvent högre och reduceringen sämre än motsvarandeför intestinala enterokocker. Indikatororganismernas koncentration i utgående avloppsvatten är enligtkorrelationsanalysen slumpmässig och inget signifikant och starkt samband fanns till de undersökta parametrarna. På grund av detta är uppskattning av mikrobiologiska utsläpp med hjälp av mätning av andra parametrarinte tillförlitlig. Den genomförda litteraturgranskningen av ozondosering visar att dosen som krävs för desinfektionav avloppsvatten behöver anpassas för varje reningsverk samt att resultat från forskningen går isär omhur doseringen bör optimeras. I recipienten har siktdjupet störst betydelse för nedbrytningen och recipientensegenskaper är viktigare än utsläppets storlek för vattenkvalitén enligt den modell som använts. Fallstudien visadeatt även vid bräddning på reningsverket hinner mikroorganismerna spädas ut och brytas ner tillräckligt föratt badvattenkvalitén inte ska klassas som otjänlig vid närliggande badplats. / Depending on the efficiency of the processes used in a wastewater treatment plant, the recipient receives watercontaining various concentrations of microorganisms. These microorganisms might infect people using therecipient for recreational purposes. The thesis aims to investigate how some process choices affect the concentrationsof microorganisms in sewage and how the concentration can be monitored with the use of other waterquality measurements. Lastly the microbial degradation after discharge in a lake was investigated. Process choiceswere evaluated through sampling before and after two biological treatment steps, one sand filter facilityand one disc filter facility. The obtained results demonstrate that among the investigated alternatives, a biologicalstep using biofilm is the most efficient for removing microorganisms, followed by sand filtration and leastefficient with high variability was disc filtration. The literature review suggests that the use of ozonation forreducing pharmaceutical residues could be efficient in reducing microorganisms, but the required dosage is notuniformly established in previous research. Statistical analysis on water quality measurements with Kendall’sTau and Partial Least Squares did not appear to be a good substitute to use for monitoring and prediction ofbacterial concentrations. The water quality of the recipient, especially the transparency for UV-light, is moreimportant for maintaining good bathing water quality than the outflow concentration of microorganisms in thesewage. In a small case study, it was shown that an official bathing site is not at risk for acute microbiologicalcontamination even when extreme rainfalls causes overflow in the upstream waste water treatment plant.

The master thesis deals with mechanical design of device used for stretching and fixing filtration fabric on plastics frames segments for disc filtration device. The thesis was solved in cooperation with IN-EKO Team company that deals with development and manufacturing of filter units. Solution is connected to already ended project FR-T13/699 (end of the year 2013). At the beginning is described the field of filtration devices in broader context with description of the overall functionality these devices and description of used elements in final design. Opening text is followed by concretization of task list and descriptions of concepts variants which are based on FEM analysis of behavior of stretched filtration fabric. The best concept is processed in detail as mechanical design along with pneumatic and PLC control design. Critical part of the design is stretching clamp which was experimentally verified by using experimental clamp in combination with testing machine. The whole design is developed for mass production of disc segments for disc filter which is projected in to the level of the automation.