Submitted by Angela Maria de Oliveira (amolivei@uepg.br) on 2018-05-23T17:33:13Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Jenzura, Nathanna Tessari.pdf: 1299612 bytes, checksum: 393334e0cc91397299fbbc9f1ed6cb45 (MD5) / Made available in DSpace on 2018-05-23T17:33:13Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Jenzura, Nathanna Tessari.pdf: 1299612 bytes, checksum: 393334e0cc91397299fbbc9f1ed6cb45 (MD5) Previous issue date: 2017-03-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O fenômeno da eutrofização é caracterizado pelo crescimento excessivo de algas devido ao excesso de nitrogênio e fósforo em corpos d’água. Combinado a esse fator, temos o fato de que as ETEs (Estação de Tratamento de Efluentes) brasileiras foram projetadas para remover a DQO (Demanda Química de Oxigênio) e não os nutrientes, com isso é necessário o tratamento terciário para atendimento à legislação. Pesquisas mostram que há a possibilidade de remover DQO e nitrogênio em um único compartimento, o que geraria economia na implantação e operação de ETEs. O objetivo dessa pesquisa foi avaliar a eficiência deum reator de leito estruturado comaeração intermitente e fluxo contínuo na remoção de nitrogênio e DQO do esgoto sanitário bruto misturado com efluente de RALF (Reator Anaeróbio de Leito Fluidizado). O reator apresentava volume útil de 8,6 L.O leito estruturado era composto por 13 cilindros de espuma de poliuretano com diâmetro igual a 2,5 cm e comprimento de 63 cm, dispostos verticalmente no interior do reator. A alimentação era feita continuamente com 50% de esgoto sanitário bruto e 50% de efluente de RALF. O experimento foi feito seguindo-se planejamento fatorial 22, que resultou em sete ensaios com quatro pontos nos níveis extremos (+1 e -1) e a triplicata do ponto central. Os fatores e respectivos níveis estipulados foram TDH (Tempos de Detenção Hidráulica) de 8, 10 e 12 horas, e tempo de aeração de 60, 75 e 90 minutos, em ciclos de 180 minutos. A razão de recirculação foi igual a 2 vezes a vazão de entrada. Nestas condições foram encontrados como média de remoção de DQO de 76%e NT (nitrogênio total) de 83%. O melhor resultado de eficiência de DQO (92%) e NT (88%), foi encontrado quando o reator operou com tempo de aeração de 60 minutos e TDH de 8 horas, tendo como concentração final DQO igual a 18 mg.L-1 eNT de 4,3 mg.L-1. A superfície de resposta foi utilizada para se avaliar os efeitos dos fatores sobre as respostas encontradas, e para desenvolver um modelo matemático que possibilitasse prever a eficiência do reator em relação à nitrificação e remoção de NT. Os resultados obtidos indicaram que o reator de leito estruturado com aeração intermitente é uma alternativa viável para remoção simultânea de DQO e NT. O modelo matemático obtido mostrou ser preditivo com relação à eficiência de nitrificação e remoção de NT. Com TDH de 9 horas e aeração de 60 minutos a eficiência teórica de nitrificação e remoção de NT obtida com os modelos propostos foi de 94 e 85%, respectivamente, e os resultados experimentais obtidos foram de 89 e 81%, respectivamente, próximos aos teóricos. / The phenomenon of eutrophication is characterized by excessive growth of algae due to excess nitrogen and phosphorus in water bodies. Combined with this factor, we have the fact that the Brazilian Effluent Treatment Plants (ETP) were designed to remove COD (Chemical Oxygen Demand) and not nutrients, so it is necessary the tertiary treatment to comply with the legislation. Research shows that there is the possibility of removing COD and nitrogen in a single compartment, which would generate savings in the implementation and operation of ETP. The objective of this research was to evaluate the efficiency of a structured bed reactor with intermittent and continuous flow in the removal of nitrogen and COD from the raw sanitary sewage mixed with UASB (Upflow Anaerobic Sludge Blanket) effluent. The reactor had a useful volume of 8,6 L. The structured bed was composed of 13 cylinders of polyurethane foam with a diameter of 2,5 cm and a length of 63 cm, arranged vertically inside the reactor. The feed was continuously fed with 50% crude sanitary sewage and 50% RALF effluent. The experiment was done following a factorial design 22, which resulted in seven tests with four points at the extreme levels (+1 and -1) and the triplicate of the central point. The factors and respective stipulated levels were HRT (Hydraulic Retention Times) of 8, 10 and 12 hours, and aeration time of 60, 75 and 90 minutes in 180 minute cycles. The recirculation ratio was equal to 2 times the inlet flow rate. Under these conditions were found to be COD removal average of 76% and NT (Total Nitrogen) of 83%. The best COD (92%) and NT (88%) efficiency results were found when the reactor operated with 60 minute aeration time and 8 hour HRT, having a final COD concentration of 18 mg.L-1 and NT of 4.3 mg.L-1. The response surface was used to verify the effects of the factors on the responses and to design a mathematic model to predict NT removal and nitrification. The results obtained allow us to consider that the structured bed reactor with intermittent aeration is a viable alternative for the simultaneous removal of COD and nitrogen compounds.The mathematical model obtained was predictive, and with a HRT of 9 hours and aeration of 60 minutes, the experimental responses for TN removal and nitrification efficiency was 81% and 89%, respectively, very close to the predicted one, that was 85% and 94%.

Water pollution has become a global issue with impacts in all countries but particularly those undergoing rapid urbanisation such as China. The review for this thesis established that in 2015 China had 3,910 urban treatment plants with daily treatment capacity of 167million cubic metres. This treatment capacity was able to serve more than 90% of the population in urban regions. Compared to the previous 20 years, these treatment facilities represented a major improvement. However, the thesis uses recent annual environmental reports to show that this level of treatment is still not enough to avoid serious water pollution, more than 30% of Chinese rivers were classified as polluted. The main reason for this it is suggested is that most of treatment infrastructure is for urban areas and the rural areas still lack even basic treatment and rural communities represents about half the total Chinese population. The statistics reported in Chapter 2.1 indicates only 25.3% of towns and 11% of villages are connected to treatment facilities. It was concluded that this lower treatment rate was the major factor impacting on the water environment. Therefore, it is important to improve treatment infrastructure in China remote areas. The literature suggested that trickling filter (TF) technology had advantages as wastewater treatment in this type of situation namely Chinese rural areas. This thesis therefore reports on research to upgrade the TF basic processes to remove newly prioritized nutrient pollutants using novel, sustainable and easily available local media, these were; zeolite, maifan stone, recycled concrete aggregate (RCA), brick, blast furnace slag and dolomite. The media were screened using simple absorption tests first focussing on P removal and then a short-listed group tested under dynamic pilot scale. Further static experiments were carried out on this group to understand the mechanisms involved. The pilot tests used the selected concrete and brick. The best performers against traditional media controls and the results showed pollutant removal (COD, TSS, Turbidity, TOC and N) in line with previous models. The media, except concrete, however released phosphorus. This was further confirmed by batch tests with different operating conditions which found the media released P when the initial P concentration was below 10mg/l or above 15mg/l. Concrete was not affected and continued to adsorb P under all conditions (Chapter 4). It was recommended that tests using crushed concrete for tertiary treatment be carried out. Concrete was further studies by isotherm models the best fit was the Langmuir equation with a maximum adsorption of 6.88mg/g. The mechanism of adsorption was ionic attraction determined by kinetic study and thermodynamic models. The adsorption capacity was compared with other literature, and the results from this study suggested a larger size of crushed concrete (2-5mm) could be used for P removal as effectively as smaller sizes. In order to determine the phase of the P adsorbed, sequential extractions were carried out. The results confirmed labile or easily removed P (LBP) dominated (44%) followed by refractory or occluded P (O-P), Ca-P, Mg-P and Al-P. The literature, suggested LBP would be easily available to plants and the RCA could be reused for plant nutrient supply. Different grades of RCA in terms of their original water to cement ratio (W/C) were also tested for P removal. The study showed high W/C ratio removed more P due to the greater porosity and larger pore sizes than the lower W/C ratio.

This thesis aims to propose a design of a vertical flow constructed wetland for a village up to 500 PE. The project is conducted for the town of Vlachova Lhota (Zlín district), and two alternatives are presented here. The first is based on mechanical pre-treatment and an intermittently loaded vertical flow constructed wetland. This alternative meets the state limits of wastewater discharge, which was demonstrated by a calibrated model of the effectiveness of an intermittently loaded vertical flow constructed wetland. This model was designed by Ing. Mirka Němcová using Hydrus software. The second alternative includes, in addition to the first design, tertiary sewage treatment. Tertiary treatment was proposed as an effective solution to removing all monitored pollutants in wastewater discharge. A combination of technologies of tertiary sewage treatment has not been put into practice, therefore the outcome and the effectiveness of the process can only be estimated. Tertiary sewage treatment would function as the first operational research unit, which could produce further findings in the field of sewage treatment using nature-based methods.

Modern, small-scale wastewater treatment faces a twofold challenge: On the one hand requirements from legal authorities regarding removal of eutrophying substances have become more demanding. On the other hand high-quality phosphorus reserves are dwindling, which has raised calls for increased recycling. The problem is acute in the county of Stockholm where about 34 000 households are identified to not possess adequate wastewater treatment facilities. In this master’s thesis, four treatment systems, of which three had some phosphorus recycling potential, were compared using life cycle assessment methodology. The small-scale treatment systems analyzed were infiltration, filter beds with Filtralite® P and Filtra P respectively as filter material and a chemical precipitation system. The system boundaries included the extraction of raw materials, production of materials and components, the construction and operation of the systems as well as deconstruction and recycling of the treatment plants. Apart from impacts on human health and acidification potential, which both proved to be of less relevance to the final results, energy usage, consumption of abiotic resources, global warming potential and eutrophication potential were taken into account in this study. The infiltration system attained the most favourable results in all impact categories save eutrophication potential, which was due to both the low usage of energy and resources as well as the system’s high life expectancy. The filter bed system using Filtralite® P demonstrated the best performance in reduction of eutrophying substances. However, the system’s energy demand and emissions of greenhouse gases by far exceeded the other systems’ results in these categories. Both the filter bed system using Filtra P and the chemical precipitation system fared relatively equal in the overall analysis, with moderate impacts in all categories. The nutrient recycling potential was shown to be limited by the waste products’ relatively high heavy metal content. Sludge from chemical precipitation had higher potential for replacement of fertilizer than filter bed material. The chemical precipitation system fared best in the overall assessment. Its technical immaturity and limited data foundation put the alternative using Filtra P into second place. The infiltration system’s limited treatment performance and inexistent recycling potential put this alternative into third place. The alternative using Filtralite® P was ruled out entirely because of its high impact on fossil fuel consumption and global warming. Based on this ranking recommendations were made. Even though the filter bed materials in this study showed excellent phosphorus removal capacity, further research into alternative filter bed materials will have to be made due to the materials’ environmental impacts in other areas. Focus should be on waste material and natural products (such as shell sand) with low environmental impacts from production. Ways of separating heavy metals from plant nutrients need to be explored if nutrient recycling is to be an aim. This study showed that good phosphorus removal characteristics can lead to an increase in other environmental impacts, which in some cases even may outweigh the positive effects of decreased eutrophication. / Modern, småskalig avloppsreningsteknik står inför två utmaningar. Å ena sidan har kraven från lagstiftaren på rening av eutrofierande ämnen ökat. Problemet är akut i Stockholms län där det finns ca. 34 000 hushåll som inte anses uppfylla reningskraven. Å andra sidan minskar fosforförekomsterna av hög kvalitet i allt större takt, vilket har väckt krav på ökad återföring av växtnäring. I detta examensarbete undersöktes fyra olika reningstekniker, varav tre har en viss återföringspotential, med hjälp av metodik från livscykelanalys. Systemen som undersöktes var infiltration, filterbäddar dels med Filtralite® P och dels med Filtra P som filtermaterial, samt ett kemikaliefällningssystem. Systemgränserna omfattade extraktion av råmaterial, produktion av anläggningsmaterial och –komponenter, uppförande och drift av systemen samt avveckling av anläggningarna och återföring av restmaterial. Förutom påverkan på mänsklig hälsa och försurningspotential, som visade sig vara mindre relevanta för slutresultaten, omfattade analysen även en undersökning av energianvändning, förbrukning av abiotiska resurser, potential för global uppvärmning och eutrofieringspotential. Infiltrationslösningen fick de mest fördelaktiga resultatvärden i alla kategorierna förutom eutrofieringspotential, vilket kan förklaras med systemets låga energi- och resursbehov samt dess höga livslängd. Filterbädden med Filtralite® P som filtermaterial uppvisade den största förmågan att reducera eutrofierande substanser. Systemets energibehov och utsläpp av växthusgaser översteg dock de andra systemens resultat i dessa kategorier kraftigt. Både anläggningen med Filtra P och kemikaliefällningslösningen fick liknande resultat, med måttlig påverkan i alla kategorier. Systemens återföringspotential visade sig vara begränsad av restprodukternas höga tungmetallhalt. Kemikaliefällt slam hade högre återföringspotential än filterbäddsmaterial. Kemikaliefällning klarade sig totalt sett bäst i studien. Den relativt obeprövade tekniska utformning och det osäkra dataunderlaget ledde till att Filtra P hamnade i rangordningen efter kemikaliefällning. Infiltrationssystemets begränsade reningsförmåga och den obefintliga återföringspotentialen ledde till att alternativet hamnade näst sist. Filtralite® P-alternativet blev placerat sist i rangordningen på grund av dess stora påverkan på förbrukning av fossila bränslen och global uppvärmning. Baserat på rangordningen utfärdades rekommendationer. Trots att filtermaterialen som undersöktes i denna studie har en utmärkt fosforreningsförmåga, kommer det att krävas fler studier med avseende på alternativa filtermaterial, eftersom materialens användning av icke-förnybara energikällor är mycket stor vid tillverkningen. Fokus borde ligga på återvunna eller naturliga material (som t.ex. snäcksand) med låg miljöpåverkan vid tillverkning. Om återföring av växtnäring ska bli ett mål inom småskalig avloppsvattenrening, måste effektiva sätt att separera tungmetaller från växtnäringsämnen utforskas. Denna studie visade att goda fosforavskiljningsegenskaper kan medföra att andra typer av miljöpåverkan ökar, vilket i vissa fall kan leda till att de negativa konsekvenserna överväger nyttan av minskad eutrofiering. / Moderne, dezentrale Abwassertechnik steht zwei großen Herausforderungen gegenüber. Zum einen sind die Ansprüche von Seiten des Gesetzgebers gestiegen, die effektivere Abwasserreinigungstechniken erfordern. Zum andern werden Phosphorvorkommen von hoher Qualität zunehmend knapper, was Rufe nach verstärkter Rückführung von Phosphor hat laut werden lassen. Im Verwaltungsbezirk Stockholm, in dem es ungefähr 34 000 Haushalte mit unzureichender Abwasserreinigung gibt, ist das Problem von besonderer Bedeutung. In dieser Diplomarbeit wurden vier Abwasserreinigungssysteme, wovon drei ein gewisses Potential für Phosphorrückführung haben, mit Hilfe einer Ökobilanzierung untersucht. Folgende Systeme wurden untersucht: Eine Infiltrationsanlage, zwei Filterbettsanlagen, eine mit Filtralite® P und eine mit Filtra P als Filtermaterial sowie ein System mit Chemikaliefällung. Die Systemgrenzen umfassten die Gewinnung und Verarbeitung von Rohstoffen, das Errichten der jeweiligen Anlage, deren Betrieb sowie Rückgewinnung und Entsorgung von Restmaterialien. Neben Auswirkungen auf die menschliche Gesundheit und Versauerungspotential, die sich im Nachhinein als weniger relevant erwiesen, wurden Energiebedarf, Verbrauch abiotischer Resourcen, Potential für globale Erwärmung und Eutrophierungspotential untersucht. Die niedrigsten Resultate in allen Kategorien außer Eutrophierungspotential wurden vom Infiltrationssystem erreicht. Filtralite® P erwies sich als am leistungsstärksten, was die Reduktion von eutrophierenden Substanzen angeht. Der Energiebedarf und die Emissionen von Treibhausgasen dieser Alternative überstieg die Ergebnisse der anderen Alternativen in diesen Kategorien doch bei weitem. Filtra P und Chemikaliefällung erzielten moderate Auswirkungen in allen Kategorien. Das Potential für die Rückführung von Pflanzennährstoffen wird, wie die Ergebnisse zeigen, vom relativ hohen Schwermetallhalt in den Restprodukten begrenzt. Chemikaliefällung ist in dieser Studie die beste Alternative. Filtra P zeigte sich als technisch noch zu wenig ausgereift und die Datenunterlage als zu unvollständig, weswegen diese Alternative an zweiter Stelle steht. Die begrenzte Reinigungsfähigkeit des Infiltrationssystemes und das nicht vorhandene Potential für Rückführung von Phosphor führten dazu, dass diese Lösung an dritter Stelle steht. Das System mit Filtralite® P als Filtermaterial wurde wegen seines großen Verbrauchs von fossilen Brennstoffen für wenig brauchbar befunden und steht damit an letzter Stelle. Trotz ihrer hervorragenden phosphorreduzierenden Eigenschaften, wird weitere Forschung im Bereich alternativer Filtermaterialien notwendig werden. Hierbei sollten natürliche Materialien (wie Muschelsand) oder Restprodukte im Mittelpunkt des Interesses stehen, um die Umweltauswirkungen gering zu halten. Wenn die Rückführung von Phosphor ein Ziel der Abwasserreinigung sein soll, müssen Lösungen, Schwermetalle von Pflanzennährstoffen zu trennen, gefunden werden. Diese Studie hat gezeigt, dass gute phosphorreduzierende Eigenschaften zu verstärkten Umweltauswirkungen in anderen Bereichen führen können, welche in manchen Fällen sogar die Vorteile einer verringerten Eutrophierung übersteigen können.

A water treatment unit consisting of two aeration basins, two settling tanks, a residence basinand a horizontal subsurface flow wetland were used to treat wastewater from an eggprocessing factory in Brazil. The aim of this paper was to determine the efficiency of thesystem in reducing nitrogen, phosphorus, BOD5 and TSS (among other parameters) andgetting a further understanding on different kinds of constructed treatment wetlands as well astheir nitrogen and phosphorus removal processes. The wastewater from the factory consistedof process water from manufacturing and water used for cleaning, no stormwater or sewagewater entered the system. Tests were taken three times a month from October 2013 ‘til April2014. The mean influent concentrations from wastewater directly from the factory were2,606 mg/L, 46.60 mg/L, 318.3 mg/L and 1,112 mg/L for BOD5, TP, TKN and TSS. Themean results of reduction through the wetlands gave the following results; BOD5 42 ± 351%,TP 66 ± 9.7%, TN 42 ± 13% and TS -11 ± 30%. Compared to other wetland systems treatingsimilar wastewater the reduction of BOD5 and TSS is low. Recommended solutions toincrease the reduction in the wetland are presented in the discussion. / Processvatten från livsmedelsindustrier och anläggningar med animalieproduktion har högakoncentrationer av organiskt material, suspenderat material och närsalter (Kadlec & Wallace,2008). Förr släpptes mycket processvattnet direkt ut till närliggande dammar, floder ellerbäckar. I moderna tider finns riktvärden satta från till exempel svenska Naturvårdsverket och det brasilianska miljödepartementet, CONSEMA, som gör att processvattnet måste förbehandlas innan det kan släppas till recipienten. Våtmarker har visat sig vara ett bra val av reningsmetod när det kommer till rening av bland annat kväve, fosfor, BOD5 och TSS(Camino et al., 2011; Johansson, 2014; Knight et al., 2000; Lin et al., 2005; Mantovi et al.,2003). De olika typer av anlagda våtmarker har för- och nackdelar, till exempel har vissa typer en högre nitrifikationsprocess och andra har en högre denitrifikationsprocess. Genom attkänna till vilka för- och nackdelar de olika typer av anlagda våtmarker har går det att skräddarsy ett behandlingssystem som uppfyller de specifika reningsändamålen för just det processvattnet. Syftet med detta arbete är att avgöra hur pass effektiv NaturOvos våtmarkreducerar föroreningar, att får en bättre förståelse av olika typer av anlagda våtmarker samt deras kväve- och fosforreningsprocesser. NaturOvos äggfabrik ligger i Salvador do Sul, Rio Grande do Sul, Brasilien. Under juni år 2013 byggdes en horizontal subsurface flow (HSSF) våtmark för att öka kväve- och fosforrening av processvattnet från fabriken. Behandlingssystemet består av en aktivslamanläggning bestående av två luftningsbassänger och två sedimenteringstankar, en uppehållsbassäng och en HSSF våtmark. Recipienten är en närliggande damm. Behandlingsvattnet som renas genom systemet innehåller processvatten och vatten som används vidrengöring av fabriken. Obehandlat vatten direkt från fabriken har ett medelvärde på2 606 mg/l för BOD5, 46,60 mg/l för TP, 318,3 mg/l för TKN och 1 112 mg/l för TSS. Provtagning av inflödes- och utflödesvatten har skett tre gånger per månad från oktober 2013 till april 2014. Medelvärdesresultat av retention i våtmarken är följande; BOD5 42 ± 351 %,TP 66 ± 9,7 %, TN 42 ± 13 % och TS -11 ± 30 %. Jämfört med andra studier (Camino et al.,2011; Johansson, 2014; Knight et al., 2000; Lin et al., 2005; Mantovi et al., 2003) är retentionav kväve och fosfor hög, men retentionen av BOD5 och TS är låg. Förbättringsförslag för att öka reningen i våtmarken redovisas i diskussionen.

<div>Excessive phosphorus (P) is a threat to water quality and aquatic life, and one of the governing causes of eutrophication in water systems. It has been the object of much research that led to the implementation of P best management practices, aimed at curbing P export from agricultural and urban landscapes. However, these efforts are somewhat insufficient to mitigate and control dissolved P transport, a P pool 100% bioavailable for aquatic biota. Recent developments in nutrient management research highlight the ability of P removal structures to sequester dissolved P from flowing water, e.g., runoff and subsurface drainage, before it reaches water bodies. Phosphorus removal is accomplished through the use of reactive filter media, which are either manufactured, mined, or industrial by-products. These media, also referred to as P sorption materials (PSMs), vary in P removal ability, due to their origin, chemical and physical properties, or the conditions under which they operate. Consequently, there is a need to fully distinguish the characteristics of PSMs and their behavior in P removal structures that result in a superior P removal performance. In this study, six different types of PSMs were characterized according to their chemical and physical nature, and PSM-P interactions. To evaluate the variability of P removal capacity of steel slag, a series of flow-through experiments were conducted, using 18 different samples from different origins and generation processes. Phosphorus removal was evaluated on uncoated and aluminum(Al)-coated steel slag samples under two residence times. After chemically characterizing the samples, we found that, for the uncoated steel slags, electrical conductivity (EC), bulk density, particle density and magnesium (Mg) content could explain around 70% of the variability of P removal. Steel slags showed a high variability in their P removal ability, but such variability could be considerably decreased when coating the slags with Aluminum (Al). The Al-coating also allowed a significantly better P removal performance under shorter residence times. Flow-through experiments were also conducted to evaluate the ability to regenerate the P removal capacity of iron(Fe)- and Al-rich PSMs across two cycles of sorption-desorption with potassium hydroxide (KOH). This study found an average P recovery of 81%, 79% and 7% for Alcan, Biomax and PhosRedeem, Fe/Al-rich PSMs commercialized for contaminant removal. The most effective regeneration treatment was characterized by the largest KOH volume (20 pore volumes) and no recirculation, with up to 100\% reported P recovery, although a more economical/feasible use of 5 pore volumes of 1M KOH with recirculation was also found to perform well. The results suggested that the use of Al/Fe-dominated PSMs in P removal structures can be extended through the demonstrated regeneration technique. Iron-rich PSMs were further evaluated in regards to their behavior under anoxic conditions, a scenario that can be found in P removal structures with bottom-upward flow regimes. To evaluate the interference of redox-induced changes on P removal, PSM samples were incubated in a biogeochemical reactor in the presence of tile drainage water. Measurements of Eh throughout the incubation period indicated that PSMs, similar to soils, developed anoxic conditions. After incubation, the dissolved P concentrations in P-loaded and original PSMs were equally low, demonstrating the stability of P retention of PSMs under anoxic conditions. Additionally, the P removal ability of the original PSMs was not significantly altered by undergoing anoxic conditions, as determined from flow-through experiments following incubation. Anoxic-induced changes did not result in any limitations to the implementation of P removal structures with bottom-upward flow. These studies demonstrated the variability in P removal capacity of PSMs as a function of chemical and physical properties, the dominant P removal mechanism, and the operational characteristics of the P removal structure. The experimental data suggests that P removal structures are an effective and environmentally safe best management practice (BMP) that, in conjunction with traditional BMPs, are critical for the mitigation of dissolved P export to water systems. </div>

Waste Stabilisation Ponds (WSPs) are characterised by low phosphorus (P) removal capacity. Heterotrophic bacteria are principal microbial agents in WSPs in addition to algae. As treatment proceeds in WSPs, algal growth increases and pH rises, this has lead to believe that P removal is mainly through sedimentation as organic P algal biomass and precipitation as inorganic P. In activated sludge treatment plants (AS), microbial P removal has been improved and is termed as enhanced biological phosphorus removal. There was a need to establish whether it was possible to enhance P removal in WSPs. A performance assessment of pond system at the University of Dare s Salaam (UDSM), Tanzania, has shown that 90% of the P removed was in the primary pond (facultative) and the rest in the maturation pond (aerobic). In these studies, a pure strain A. hydrophyla was isolated from an activated sludge wastewater treatment plant in Sweden. This plant has a train that functions with enhanced biological phosphorus removal. The strain was tested for P uptake in minimal media supplemented with glucose, succinate or acetate, grown aerobically and anaerobically/aerobically. This strain was able to take up P without having been subjected to the anaerobic phase. It was observed that P uptake was enhanced after the anaerobic phase with media supplemented with glucose, but not with succinate or acetate. Phosphorus uptake repeatedly followed the bacterial growth pattern with correlation coefficients of more than 95%. Therefore P removal has a direct correlation with bacterial growth. Two isolates Acinetobacter sp. (isolated from the primary facultative pond) and E .coli (isolated from the maturation pond) were obtained from a tropical WSP treatment system at the UDSM. They were subjected to aerobic P uptake experiment similar to those of A.hydrophyla. The uptake per unit absorbance of bacterial growth was found to be comparable to that of A.hydrophyla, isolated from AS. These results showed that heterotrophic activity is important in WSPs. It is possible to enhance P removal in these systems by designing the primary ponds for maximum heterotrophic activity and probably enrichment. / QC 20101119

It is generally accepted that a decrease in temperature causes the rates of chemical and biochemical reactions to slow down, usually resulting in poorer performance of biological wastewater treatment systems. Despite this, early researchers repeatedly showed that excess biological phosphorus removal (EBPR) was more efficient at colder temperatures. Recent studies, however, have demonstrated that the reaction rates of EBPR processes decrease with temperature in accordance with Arrhenius' Law, resulting in an apparent contradiction in the literature. The objective of this study was to investigate the EBPR temperature controversy. The experimental systems used were two, lab-scale UCT configuration plants fed with acetate as the sole volatile fatty acid (VFA) source. The results showed that EBPR systems do perform more efficiently at colder temperatures, i.e., at 5°C compared to 20°C. The reason for better system performance was determined to be related to reduced competition for substrate in the non-oxic zones that results in an increased population of phosphate accumulating organisms (PAOs) relative to non-PAOs and, therefore, greater EBPR efficiency even though the reaction rates are slower. The proliferation of PAOs relative to non-PAOs at cold temperature indicates that some of the PAOs are psychrophilic, i.e., they have alternate biochemical pathways that give them a competitive advantage over bacteria dependent upon glycogen metabolism. The activated sludge acclimated to 20°C had relatively high polyhydroxyvalerate (PHV) and glycogen contents relative to sludge acclimated to 5°C. It was initially hypothized that there is a significant competition between PAO and glycogen accumulating organisms (GAOs) at 20°C and cold temperature (5°C) nearly eliminates this competition in favor of the PAOs. A series of batch test experiments revealed that despite similar acetate utilization by the sludges grown at the two temperatures nearly 30% less PHA was produced by the sludge taken from the 20°C reactor, indicating that GAOs were a small fraction of the population at 20°C. Transmission electron microscopy pictures showed that the biomass acclimated to 20°C had a much more diverse bacterial population than the biomass acclimated to 5°C. However, no GAO population was detected in electron microscopy samples under any temperature conditions. The decreased P removal efficiency at 20°C was then attributed to the presence of fermentative or other non poly-P bacteria that are capable of utilizing substrate under anaerobic conditions. PHA production greatly increased at 5°C, whereas glycogen metabolism substantially reduced. Even though glycogen is an essential requirement for EBPR mechanism, the EBPR microorganisms have the ability to adapt their metabolic pathways to environmental conditions and greatly reduce their need for glycogen. It is apperant that cold temperature inhibits some of the key enzymes in glycogen metabolism resulting in lower glycogen accumulation that in turn increases the EBPR performance. Therefore temperature not only exerts selective pressure on the dominant population but also alters the metabolic pathways of the EBPR process. Increased glycogen accumulation, as observed in this study at 20°C, may not be related to GAO proliferation as suggested by Filipe et al. (2001) instead it may be related to EBPR bacteria to efficiently use glycogen metabolism. Current models (Brdjanovic et al. 1997; Filipe et al. 2002) consider that GAO metabolism is an integral part of EBPR metabolism and the performance of EBPR processes depends on PAO/GAO fraction in the EBPR system. No GAO proliferation was observed even the A/O process was operated without P addition for more than 3 weeks at 10°C. Therefore such important concept should be further investigated before it is included in EBPR models. EBPR stoichiometry was presumed to be insensitive to temperatures (Brdjanovic et al. 1997). However, observed stoichiometric values of PHA storage per unit glycogen utilization and PHA utilization per unit glycogen rephlenishment were quite different at different temperatures. Temperature, therefore, not only affects the kinetics of EBPR systems but also affects the EBPR stoichiometry. Most prokaryotic cells have the ability to alter their cellular membrane fatty acid composition as temperature decreases to counteract the adverse effects of temperature on membrane fluidity (Becker et al., 1996). This unique ability is known as "homeoviscous adaptation". In this study, homeoviscous adaptation by EBPR activated sludge was investigated for a series of temperatures ranging from 20°C to 5°C using one of the lab scale EBPR systems. The fatty acid analysis results showed that the unsaturated to saturated fatty acid ratio increased from 1.40 to 3.61 as temperature dropped from 20 to 5°C. The increased cis-9-hexadecanoic acid (C16:1) at 5°C strongly indicated the presence of homeoviscous adaptation in the EBPR bacterial community. Thus the cell membranes of the EBPR community were still in a fluid state, and solute transport and proton motive force mechanisms were operable even at 5°C. It was concluded that loss of EBPR performance at low temperatures, as reported by McClintock et al. (1992) was not related to the physical state of the cellular membranes, but was probably caused by unsuitable operational conditions. Even though the transport of volatile fatty acids (e.g. acetate) is an integral part of EBPR biochemistry and stoichiometry, this important concept has been ignored. Fleet (1997) concluded that acetate entry into bacterial cells in EBPR sludge was simple passive diffusion based upon the results of a single study (Baronofsky et al. 1984). However, this study showed that neither acetate nor propionate can cross the cell membrane via simple passive diffusion. The existence of apparent saturation curves when the substrate uptake rates (acetate and propionate) were plotted against the substrate concentrations suggested that transport of volatile fatty acids obey facilitated or active transport. Following from the above results, an investigation of the impacts of operational conditions such as low solids retention time (SRT), presence of electron acceptors in the non-oxic zones, low anaerobic detention time, and lack of acclimation was performed. The results showed that the "critical, i.e., wash-out" SRT increased as temperature decreased, but if the biomass was permitted to acclimate to the lower temperature, a major population shift would occur which would increase the capacity of the system for phosphorus (P) removal. When the 5 °C sludge was allowed to acclimate at a relatively high SRT (18 d), the system's P-removal capacity greatly surpassed that of the 20 °C system. The decrease in EBPR performance because of the presence of nitrates in the non-oxic zones was determined to be greater than what would be predicted based on accepted stoichiometry. / Ph. D.

Although enhanced biological phosphorus removal (EBPR) and complete biological nutrient removal (BNR) systems can be operated successfully by experienced operators, the accuracy of design and strength of the scientific background need to be reinforced to enable accurate modeling and economically optimal design. One way to accomplish this would be through a better understanding of the biochemical mechanisms and microbial population dynamics that determine the reliability and efficiency of EBPR, and the utilization of this information to improve the design and operation of BNR plants. Such knowledge will also contribute to better structure of modeling tools that are used for design and educational purposes. The current body of knowledge is limited to observational studies that lack detailed biochemical explanations backed with a series of well planned experiments, and this has introduced uncertainties and inaccuracies into the biochemical and design models. Therefore, this study mainly covers a biochemical survey of the underlying metabolisms of active populations in BNR sludges. BNR biomass with biological phosphorus removal (BPR) capability was cultivated in continuous flow reactor (CFR) systems, configured as either University of Cape Town (UCT) and anoxic/oxic (A/O) systems. Following an acclimation period at 20°C, low temperature stress (5°C) was imposed on one UCT system for investigation of the response of the microbial consortium responsible from EBPR activity under cold temperature. Once a stable population with EBPR capabilities is established in each system, activities of ten enzymes that are hypothesized to be taking part in the EBPR metabolism were measured. These enzymes were selected among those that take part in major known pathways of bacterial energy and growth metabolism. Also, 13C-NMR was used as a tool to monitor the flux of labeled carbon in and out of pools of cellular storage; i.e. glycogen and polyhydroxyalkanoates (PHA). Combining the gathered information, accurate mass balances of carbons and reducing equivalents were calculated, eventually leading to determination of the biochemical pathways utilized by the EBPR consortium. Additionally, anaerobic stabilization of COD, a long debated but empirically established phenomenon, was addressed during the study. Considering the pathways proposed to be operative under different conditions imposed on the EBPR systems, a biochemical explanation for the occurrence of COD stabilization in wastewater treatment systems that incorporate anaerobic zones was proposed. Accordingly, depending on the pathways actively used by a microbial consortium, electrons stored in NADH and FADH2 can either be transferred to the terminal electron acceptor, oxygen, or they can be incorporated into storage polymers such as glycogen for future use. Such differences in metabolism reflect in the quantity of the oxygen consumed in the aerobic reactors. Thus, the correct incorporation of anaerobic stabilization of COD into process design would reduce design aeration requirements and result in economic savings during both construction and operation. / Ph. D.

Enhanced biological phosphorus removal (EBPR) has been widely used in municipal wastewater treatment, but no previous studies have examined the application of EBPR to treat dairy manure. This study was conducted to evaluate the (i) performance of pilot-scale EBPR systems treating liquid dairy manure, to balance the ratio of nitrogen to phosphorus in manure to meet crop nutrient requirements, (ii) effects of dissolved oxygen and solids retention time on the efficiency of EBPR, and (iii) effectiveness of gravity thickening for reducing the volume of harvested EBPR aerated mixed liquor. Two pilot-scale EBPR systems were used in this study. The ratio of the manure chemical oxygen demand expressed as volatile fatty acids to phosphorus used ranged from 18:1 to 45:1. The phosphorus removal efficiencies of the EBPR system were investigated at three solids retention times (4, 6 and 10 d), and three dissolved oxygen levels (3, 4 and 6 mg O₂/L). The total phosphorus removal was highest (84%) at 10 d solids retention time and lowest (63%) at 4 d solids retention time. The sludge from the 6 d solids retention time tests had better sludge settling characteristics with a sludge volume index of 62 mL/g compared to 80 mL/g for the 4 d solids retention time. The EBPR system achieved 90% dissolved reactive phosphorus removal when the system was operated at 4 mg O₂/L, and the ratio of nitrogen to phosphorus in effluent increased to about 5:1, which was higher than the normal ratio in dairy manure. On the other hand, phosphorus removal performance deteriorated when dissolved oxygen level was 3 mg O₂/L. In the gravity thickening tests, 93-95 % total suspended solids (TSS) was removed from the settled supernatant, with 1.2 to 1.54 % total solids (TS) in the settled solids after 90 min gravity-induced thickening. The extent of phosphorus release during gravity thickening process needs to be further investigated. / Master of Science