Thesis (M.S.)--University of Hawaii at Manoa, 2005. / Includes bibliographical references (leaves 64-73). / xi, 73 leaves, bound ill. 29 cm

[Truncated abstract] An ethanol delivery system, consisting of silicone (poly(dimethylsiloxane)) tubing coiled and shaped as mats, was characterised and evaluated for its potential to act as a permeable reactive barrier (PRB), to promote reducing conditions and enable the enhanced bioremediation of a variety of groundwater contaminants in situ. Aqueous ethanol solutions were recirculated through the inner volume of the silicone polymer tubing in the mat, to allow permeation and delivery of ethanol by diffusion through the tubing walls to a target contamination zone. The aim of the system was to provide control over subsurface geochemistry by overcoming carbon source limitations, and as a result stimulate indigenous bacteria to remove contaminants. The physical properties of the silicone tubing were initially characterised, which included the determination of the ethanol sorption and diffusion properties of the tubing. A model for the mass of ethanol transferred via diffusion from an aqueous solution on the inner volume of a length of polymer tubing was developed to enable prediction of the ethanol delivery capacity of the silicone polymer mats. A number of large-scale laboratory column studies were then conducted to validate this ethanol mass delivery model, and to evaluate the use of silicone polymer mats to deliver ethanol and promote the biodegradation of a range of different contaminated groundwaters. The laboratory column experiments were observed to produce ethanol mass flux delivery statistically similar to that predicted by the model; however this was only with the application of an effective diffusion coefficient within the model, which was determined from the model under subsurface-simulated conditions. Ethanol delivery using the silicone tubing polymer mat system was also quantified in a pilot field-scale demonstration. The mass of ethanol delivery in the field was shown to be within the range of model-predicted ethanol delivery; however delivery was not as consistent and predictable as that observed in the column studies. Successful ethanol enhanced nitrate contamination removal (via denitrification) was observed at a field scale. For field applications, this innovative polymer mat amendment delivery system may provide targeted, predictable and cost-effective amendment delivery compared to aqueous injection methods for groundwater bioremediation, however, knowledge and quantification of the hydrogeology of the particular field site is required. Two other ethanol-driven biologically-mediated contaminant removal processes were also investigated in the laboratory-scale soil column studies, and included the assessment of the removal of dissolved metals/sulfate via sulfate reduction and metalsulfide precipitation, and the removal of trichloroethene via reductive dechlorination.

Wastewater treatment performance of three pilot-scale packed-bed anaerobic digesters with walnut shell medium was researched for treating dairy freestall barn flushwater. Reciprocation mixing was evaluated as a means to lessen channelization in the media bed and to improve biogas production and organic matter removal at ambient temperatures. Reciprocation has been used in biological nitrogen removal systems to introduce air into the system to repeatedly oxygenate nitrifying biofilm along with mixing (Behrends et al. 2003), but the anaerobic systems benefit from mixing. Two tanks were used in each system, where one was full and one was empty at any given time. Water was repeatedly pumped from one tank to the other and back again (reciprocation). A key research objective was to determine the minimum reciprocation frequency (between 0-10 per day) while still maintaining moderate methane production and treatment performance. Broken walnut shells with a specific surface area of 360 m2/m3 were used as the packed media. Digester influent, which was pretreated to remove large solids, had the following characteristics: total solids (TS) of 5.5 g/L, volatile solids (VS) of 2.8 g/L, 5-day carbonaceous biochemical oxygen demand (cBOD5) of 800 mg/L, and chemical oxygen demand (COD) of 4340 mg/L. Average digesting liquid temperatures ranged from 14.1 to 23.6 °C. At 6-day theoretical hydraulic residence times (V/Q where V is Lliquid, which is volume of liquid occupying the digester pores, and Q is total daily influent flow) and 1 reciprocation per day, methane production was 0.060 ± 0.10 LCH4/Lliquid-day and at 10 reciprocations methane production 0.058 ± 0.14 LCH4/Lliquid-day (mean ± standard deviation of measurements over time). COD percent removals were both 51% at 6-day V/Q. Since multiple reciprocations did not appear to make a difference in methane production and treatment performance, fewer reciprocations were used in subsequent experiments. Higher flow rates were also used in subsequent experiments to accelerate sludge clogging and channelization in the walnut-shell bed and thereby allow detection of any advantage provided by reciprocation compared to an upflow reactor. At 0 and 1 reciprocations per day and 0.35 and 0.50-day V/Qs, respectively, methane production was 0.24 ± 0.08 and 0.23 ± 0.08 LCH4/Lliquid-day and COD percent removal was 17 and 22%. Over the study period of 226 days, walnut shell porosities decreased due to sludge accumulation from 0.68 and 0.64 (start-up or clean-bed) to 0.31 and 0.24 in the 1 and 0 reciprocation per day reactors. Sludge accumulation and channelization did not appear to be affected by reciprocation mixing on the scale of this study.

A submerged-media biological aerated filter (BAF) has been studied to 1) evaluate oxygen transfer kinetics under conditions without biological growth and 2) determine the influence of biological growth on the rate of oxygen transfer. Collectively, the study evaluates the rates of supply and consumption of oxygen in BAFs. The mass-transfer characteristics of a submerged-media BAF were initially determined over a wide range of gas and liquid flow rates without the presence of bacteria. The mass-transfer coefficients (KLa(T)) were measured using a nitrogen gas stripping method and were found to increase as both gas and liquid superficial velocities increase, with values ranging from approximately 40 to 380 h??. The effect of parameters including the gas and liquid velocities, dirty water to clean water ratio, and temperature dependence was successfully correlated within +/- 20% of the experimental KLa value. The effects of the media size and gas holdup fractions were also investigated. Stagnant gas holdup did not significantly influence the rate of oxygen transfer. Dynamic gas holdup and the difference between total and stagnant gas holdup were found to increase with an increase in gas velocity. Neither liquid velocity nor liquid temperature was determined to have a significant impact on gas holdup. A tertiary nitrification BAF pilot unit was then operated for 5 months downstream of a secondary treatment unit at a domestic wastewater treatment facility. The study investigated the oxygen transfer capabilities of the nitrifying unit with high oxygen demand requirements through a series of aeration process tests and explored the presence of oxygen transfer enhancements by further analyzing the actual transfer mechanism limitations. It was determined that (assuming OTE equals 20 percent) aerating the BAF pilot unit based on the stoichiometric aeration demand resulted in overaeration of the unit, especially at lower pollutant loading rates. Endogenous respiration contributed to only 2 to 7 percent of the total oxygen demand with regions of biomass activity changing with varying loading conditions. An enhanced oxygen transfer factor was determined in the biologically active pilot. Although it cannot be definitively concluded that the observed oxygen transfer factor is either due to biological activity or not simply an artifact of measurement/analysis techniques, the enhancement factor can be mathematically accounted for by either an increase in the KLa factor or the associated driving force using a proposed enhanced bubble theory. / Master of Science

The Integrated Film Activated Sludge Process (IFAS) was developed to reduce the cost of additional facilities required to complete year round nitrification in the design of new or retrofit wastewater treatment plants. The purpose of this project was to develop a computer-based mechanistic model, called IFAS, which can be used as a tool by scientists and engineers to optimize their designs and to troubleshoot a full-scale treatment plant. The program also can be employed to assist researchers conducting their studies of IFAS wastewater treatment processes. IFAS enables the steady-state simulation of nitrification-denitrification processes as well as carbonaceous removal in systems utilizing integrated media, but this current version supports only sponge type media. The IFAS program was developed by incorporating empirical equations for integrated biofilm carbonaceous uptake and nitrification developed by Sen and Randall (1995) into the general activated sludge model, developed by the International Association on Water Quality (IAWQ, previously known as IAWRC), plus the biological phosphorus removal model of Wentzel et al (1989). The calibration and evaluation of the IFAS model was performed using existing data from both an IFAS system and a conventional activated sludge bench-scale plant operated over a wide range of Aerobic Mean Cell Residence Times (Aerobic MCRT's). The model developed provides a good fit and a reasonable prediction of the experimental data for both the IFAS and the conventional pilot-scale systems. The phosphorus removal component of the model has not yet been calibrated because of insufficient data and the lack of adequately defined parameters. / Master of Science

The performance of fibrous biomass support media (Ringlace) and porous spongelike biomass support media (Captor) was evaluated for enhanced nitrification and denitrification in a pilot-scale Virginia Initiative Project (VIP) biological nutrient removal (BNR) process. Four separate pilot-scale treatment trains were constructed and operated during this research. Three of the four treatment trains were operated with fixed film media (Ringlace/Captor) incorporated in the aerobic zone of the system and are referred to as the Integrated Fixed Film Activated Sludge (IFAS) systems. A fourth treatment train (Control train) was operated without any fixed film media. All experiments in this research were performed using domestic wastewater from Blacksburg, Virginia, and the Virginia Tech campus. Enhanced nitrification was observed in the IFAS system containing porous biomass support media (Captor) that was freely suspended in the mixed liquor of the aerobic zone. Near-complete nitrification was observed in the IFAS system containing Captor media even at total suspended growth MCRTs as low as 5.6 days and a 12°C liquid temperature. Significantly higher nitrification rates were observed in the IFAS system containing Captor media compared to both the IFAS system containing Ringlace media and the control train. However, there was less denitrification in the aerobic zone of the IFAS systems containing Captor media compared to the Ringlace media systems. Enhanced nitrification could not be statistically shown in the IFAS system containing Ringlace media. The overall nitrification rates in the Ringlace media system were about the same as the control train for the MCRTs and temperatures used during this research. However, a significantly greater amount of denitrification was observed in the aerobic zone of the IFAS system containing Ringlace media compared to both the IFAS system containing Captor media and the control system. Microscopic examination of the growth on the fixed film media (Ringlace and Captor) showed that red worms always grew on the Ringlace media, and were detrimental to performance on at least one occasion. Methods for controlling the worms were developed and applied successfully. During certain operating phases, lower sludge productions and observed sludge yields were measured in the IFAS system containing Ringlace media. However, a Statistical difference could not be calculated between the sludge production in the Ringlace media system and the control system. Lower sludge production and observed sludge yield were also observed in the IFAS system containing Captor media, but only two data points were available and a Statistical t-test analysis was not possible. / Master of Science

M. Tech. (Department of Civil Engineering, Faculty of Engineering and Technology), Vaal University of Technology. / Over time, the quality standard of stormwater in the City of Ekurhuleni (CoE) has deteriorated due to industrial, commercial, residential and farming activities. Stormwater quality directly impacts the treatment chain of potable water, and therefore, it should be kept in check at all stages. Innovations in the biofiltration process can provide useful, practical solutions to overcome crucial stormwater pollution problems. In 2013, the CoE developed stormwater design guidelines and standards to be implemented for the design of stormwater management, which include the principles of Water Sensitive Urban Design (WSUD) and Sustainable Urban Drainage Systems (SuDS) in particular. The CoE stormwater design guidelines and standards do not provide details on how the city plans to implement SuDS treatment trains to reduce stormwater pollution experienced by the city. This study aimed to verify the efficiency and effectiveness of vegetated biofilters on the stormwater treatment using CoE – Olifantsfontain's natural stormwater and to determine the most suitable vegetation to be used in the region. The CoE experimental case study was conducted to assess the efficiency of selected vegetated biofilters in lowering the concentration of orthophosphate (PO4-3), ammonium (NH4+), and nitrate (NO3-) from Tembisa/Olifantsfontain stormwater. In the experimental setup, six selected plant species were planted into 30 vegetated biofilter columns, namely: Agapanthus praecox (Dryland plant), Carpobrotus edulis (Dryland plant), Stenotaphrum secundatum (Dryland plant), Zantedeschia aethiopica (Wetland plant), Typha capensis (Wetland plant) and Phragmites australis (Wetland plant). The six species were grouped according to general habitats, i.e. three wetland and three dryland plants. Wetland plants were planted into fifteen vegetated biofilters, and dryland plants were also planted on another fifteen vegetated biofilters. The biofilters contained layers of sandy loam soil, coarse and and gravel sand. Each biofilter had a designated inlet and outlet section fitted with a gate valve to control retention time. The raw stormwater consisting of natural nutrient pollutants was applied to each vegetated biofilter through the inlet section. The samples were collected from the inlet and outlet of the six grouped vegetated biofilters during the month of June. All six plant species reduced outflow concentrations of PO4-3 and NH4+ by an average of 99% and 98%, respectively. The results also show that all plant species excluding Phragmites australis were able to reduce NO3- with outflow concentrations being reduced by an average of 58%. From the results obtained, it may be concluded that all the six plant species may be suitable variants to be applied as biofilter material for the purposes of treating urban stormwater in the CoE. The reason is that the determined removal efficiencies for bio-retention fall within 50% – 60% for PO4-3, and 40% - 50% for NH4+ and NO3- respectively. The results also show that if the plant species were applied for SuDs in the CoE, there could be a great improvement in the urban stormwater quality with the consequent improvement in both surface and groundwater quality of the receiving water bodies in the area. Regardless of the nutrient removal by selected plant species, the inclusion of vegetation in a field setting would slow flow rates and thus encourage infiltration into the soil, improve water quality, and support urban biodiversity. In the CoE, all the selected species could be used in the SuDS treatment trains targeting PO4-3, NH4+ and/or NO3-. The case study results provide a informed records for the CoE in the future/intended application SuDs in the upgrade/rehabilitation of its stormwater system.

Esta pesquisa enfoca a avaliação do desempenho de nova configuração de unidade para tratamento biológico de esgoto sanitário por processo combinado, visando à remoção de nutrientes, especialmente nitrogênio. O sistema construído em escala piloto tem volume útil igual a 71,48 litros. Nesta nova configuração de reatores para tratamento terciário de esgoto sanitário, utilizaram-se três reatores sobrepostos, sendo: um reator UASB - “Upflow Anaerobic Sludge Blanket"; um reator de leito móvel e filme fixo aeróbio (com aplicação de oxigênio puro); e, um reator de leito móvel e filme fixo com ambiente anóxico. O material suporte utilizado nos reatores de leito móvel e filme fixo constituiu alternativa inédita no tratamento de efluentes líquidos. Foram utilizadas cavilhas “ranhuradas" de madeira, de dimensões aproximadas de 8,0 mm de diâmetro por 8,0 mm de comprimento. O desempenho geral do sistema quanto à remoção de matéria carbonácea e compostos nitrogenados, e as associações microbianas formadas nos três reatores são objetos principais de estudo deste trabalho. Foram obtidos resultados de remoção de DQO e de nitrogênio bastante satisfatórios, sobretudo quando o tempo de detenção hidráulica total esteve próximo a 20 horas, incluindo o compartimento de decantação (94,6 % para DQO; e 96,7 % para N-NTK, com formação de nitrato em concentrações inferiores a 10,0 mgN-NO3-/l). O TDH estudado variou entre 5 e 24 horas para os sistema completo. O estudo dos consórcios de microrganismos forneceu excelentes resultados quanto à quantidade, diversidade, e atividade das populações desenvolvidas nos diferentes ambientes, confirmando o bom desempenho do sistema e o fornecimento de ambiente adequado para o desenvolvimento das diferentes populações nos três reatores. A idealização desta configuração tem como finalidade realização de tratamento de esgoto sanitário até nível terciário em planta compacta, podendo ser utilizada por pequenas e grandes comunidades, devido à possibilidade de se construir diversos módulos do sistema proposto. / This research is focused on the performance evaluation of a new system configuration of combined biological reactors, treating domestic wastewater till tertiary level. The pilot scale proposed system had a total useful volume of 71,48 liters. This new configuration involves three types of superposed reactors: an Upflow Anaerobic Sludge Blanket reactor; an aerobic fixed film mobile bed reactor (fed with pure oxygen); and a fixed film mobile bed reactor at anoxic environment. The support material used inside the fixed film mobile bed reactors was wood made grooved dowels. The main purposes of this work are to evaluate the systems general performance regarding COD and nitrogen removal, and the microbial associations inside the reactors. It reached quite satisfactory results regarding COD and nitrogen removal when the total hydraulic retention time (HRT) was around 20 hours, including the clarification zone volume (94,6 % for the COD; and 96,7 % for the TKN-N, whit nitrate formation below 10,0 mgN-NO3-/l). HRTs from 5 to 20 hours were studied. The microbial associations were present in large number, with a great diversity and high specific activities at the different environments, confirming the good results obtained and the suitable environment provided for the growth of the different populations inside the three reactors. The idealization of this treatment system has the goal to treat domestic wastewater from small to large communities till tertiary level, in compact treatment plants, due to the possibility of constructing several modules of the system.

Esta pesquisa enfoca a avaliação do desempenho de nova configuração de unidade para tratamento biológico de esgoto sanitário por processo combinado, visando à remoção de nutrientes, especialmente nitrogênio. O sistema construído em escala piloto tem volume útil igual a 71,48 litros. Nesta nova configuração de reatores para tratamento terciário de esgoto sanitário, utilizaram-se três reatores sobrepostos, sendo: um reator UASB - “Upflow Anaerobic Sludge Blanket”; um reator de leito móvel e filme fixo aeróbio (com aplicação de oxigênio puro); e, um reator de leito móvel e filme fixo com ambiente anóxico. O material suporte utilizado nos reatores de leito móvel e filme fixo constituiu alternativa inédita no tratamento de efluentes líquidos. Foram utilizadas cavilhas “ranhuradas” de madeira, de dimensões aproximadas de 8,0 mm de diâmetro por 8,0 mm de comprimento. O desempenho geral do sistema quanto à remoção de matéria carbonácea e compostos nitrogenados, e as associações microbianas formadas nos três reatores são objetos principais de estudo deste trabalho. Foram obtidos resultados de remoção de DQO e de nitrogênio bastante satisfatórios, sobretudo quando o tempo de detenção hidráulica total esteve próximo a 20 horas, incluindo o compartimento de decantação (94,6 % para DQO; e 96,7 % para N-NTK, com formação de nitrato em concentrações inferiores a 10,0 mgN-NO3-/l). O TDH estudado variou entre 5 e 24 horas para os sistema completo. O estudo dos consórcios de microrganismos forneceu excelentes resultados quanto à quantidade, diversidade, e atividade das populações desenvolvidas nos diferentes ambientes, confirmando o bom desempenho do sistema e o fornecimento de ambiente adequado para o desenvolvimento das diferentes populações nos três reatores. A idealização desta configuração tem como finalidade realização de tratamento de esgoto sanitário até nível terciário em planta compacta, podendo ser utilizada por pequenas e grandes comunidades, devido à possibilidade de se construir diversos módulos do sistema proposto. / This research is focused on the performance evaluation of a new system configuration of combined biological reactors, treating domestic wastewater till tertiary level. The pilot scale proposed system had a total useful volume of 71,48 liters. This new configuration involves three types of superposed reactors: an Upflow Anaerobic Sludge Blanket reactor; an aerobic fixed film mobile bed reactor (fed with pure oxygen); and a fixed film mobile bed reactor at anoxic environment. The support material used inside the fixed film mobile bed reactors was wood made grooved dowels. The main purposes of this work are to evaluate the systems general performance regarding COD and nitrogen removal, and the microbial associations inside the reactors. It reached quite satisfactory results regarding COD and nitrogen removal when the total hydraulic retention time (HRT) was around 20 hours, including the clarification zone volume (94,6 % for the COD; and 96,7 % for the TKN-N, whit nitrate formation below 10,0 mgN-NO3-/l). HRTs from 5 to 20 hours were studied. The microbial associations were present in large number, with a great diversity and high specific activities at the different environments, confirming the good results obtained and the suitable environment provided for the growth of the different populations inside the three reactors. The idealization of this treatment system has the goal to treat domestic wastewater from small to large communities till tertiary level, in compact treatment plants, due to the possibility of constructing several modules of the system.

Partial Nitritation/Anammox process (deammonification process), by which occurs oxidation of ammonium to nitrogen gas by autotrophic bacteria in anaerobic conditions, considered to be cost-effective and environmentally friendly method of nitrogen removal. Present research work focuses on achieving a high nitrogen removal degree, thanks to Anammox bacteria, while providing the best performance of the ongoing process. Integrated fixed-film activated sludge (IFAS) reactor was supplied with the main stream of the wastewater after UASB reactor, characterized by low concentration of nitrogen and organic matter. The bacteria ability to accommodate, were tested in the biofilm and in the activated sludge, depending on the different stages in which the process were being conducted. Batch test, such as Specific Anammox Activity (SAA), Nitrate Uptake Rate (NUR) and Oxygen Uptake Rate (OUR), were used for the evaluation of activity of various groups of bacteria. On the basis of laboratory analysis verified the values obtained from the batch tests. It was determined that a high degree of nitrogen removal (92% of NH4-N) was achieved thanks to the dominant activity of the Anammox bacteria, with low participation of other groups of bacteria. It was also proved, that Anammox bacteria activity were overwhelming in the biofilm. Dominant role of Ammonium Oxidizing Bacteria (AOB) was associated with high activity of Anammox bacteria, which together satisfyingly out-competed Nitrite Oxidizing Bacteria (NOB) and heterotrophic bacteria. It has been shown that Anammox bacteria quickly adapt to the new conditions and they are able to assume a dominant role, even in the case of inoculation of the reactor with the sludge from SBR. This allows conclude, that in the case of operational problems, the reactor can be supplied from another source, in order not to inhibit the process.