Over recent decades, environmental regulations on wastewater treatment plants (WWTP) have trended towards increasingly stringent nutrient removal requirements for the protection of local waterways. However, such regulations ignore the other environmental impacts that might accompany the apparent improvements to the WWTP. This PhD thesis used Life Cycle Assessment (LCA) to quantify these environmental trade-offs, and so better inform policy makers on the wider benefits and burdens associated with wastewater treatment. A particular focus was also given to the generation of methane and nitrous oxide in wastewater systems, since the quantification of greenhouse gas (GHG) emissions from WWTPs is presently a substantial area of uncertainty. Rapid changes to the GHG regulatory landscape mean that this level of uncertainty, now represents an unacceptable business risk for many water utilities. Specifically, there were three research objectives of this thesis: Research Objective No.1 – Environmental optimisation of wastewater treatment systems – For typical receiving environments, the optimum wastewater treatment system configuration is not necessarily at the limit of best practice for nutrient removal. The LCA approach to this research objective was divided into two stages. In stage I, a comprehensive desk-top life cycle inventory of ten different wastewater treatment scenarios was completed. The scenarios covered six process configurations and treatment standards ranging from raw sewage to advanced nutrient removal. It was shown that physical infrastructure, chemical usage and operational energy all increased with the level of nutrient removal. These trends represented a trade-off of negative environmental impacts against improved local receiving water quality. In stage II of the LCA, a quantitative life cycle impact assessment of the ten scenarios, referenced against Australian normalisation data, was completed. From a normalised perspective against Australian society, the contribution of WWTPs to headline issues such as global warming and energy consumption was found to be very small. The more prominent environmental impact categories were eutrophication due to nutrient discharge and toxicity issues, due to heavy metals in biosolids. There existed a broader environmental trade-off for nutrient removal, that could only be justified by society and regulators implicitly placing higher value on local water quality, than on other global environmental pressures. In light of this quantitative LCA, regulatory agencies should consider the broader environmental consequences of their policies such as the Queensland Water Quality Guidelines. It is suggested that the scope of WWTP licensing considerations should be widened from a singular focus on water quality objectives, to a more comprehensive LCA-based approach. Research Objective No. 2 – Quantification of nitrous oxide emissions from biological nutrient removal (BNR) wastewater treatment plants – Current GHG assessment methods for wastewater treatment plants are grossly inaccurate because of significant unaccounted N2O emissions. The research for objectives two and three was funded by the Water Services Association of Australia (WSAA), which is the peak body of the Australian urban water industry. Thus, whilst the earlier LCA results suggested that GHG emissions from WWTPs were insignificant from a national perspective, the industry is actually very engaged on this issue from an environmental responsibility and business risk perspective. This PhD study adopted a rigorous mass balance approach to determine N2O-N generation at seven full-scale WWTPs. The results varied considerably in the range 0.006 – 0.253 kgN2O-N generated per kgNdenitrified (average: 0.035 +/- 0.027). These results were generally larger than the current default value assumed in the National Greenhouse and Energy Reporting (Measurement) Technical Guidelines (i.e. 0.01 kg N2O-N.kgN-1denitrified). High N2O-N generation was shown to correspond with elevated bulk NO2--N concentrations in the bioreactor. The results also suggested that WWTPs designed for low effluent TN have lower and less variable N2O generation than plants that only achieve partial denitrification. Research Objective No.3 – Quantification of methane emissions from low-strength wastewater collection systems – Current default GHG assessment methods for sewerage systems are grossly inaccurate because of significant unaccounted CH4 emissions from rising mains. Presently, international GHG guidelines state that “wastewater in closed underground sewers is not believed to be a significant source of methane” (IPCC, 2006). However, the results of this PhD research demonstrated that methane generation in rising main sewers is substantial. It was shown that dissolved methane concentrations were dependent upon pipeline geometry and sewage residence time. Consequently, it was possible to develop a simple, yet robust, theoretical model that predicted methane generation from these two independent parameters. This model provides a practical means for water authorities globally to make an estimate of the currently unaccounted methane emissions from pressurised sewerage systems.

There is a regulatory tension within wastewater treatment, between the requirement to meet tightening consents and the need to reduce the carbon footprint of treatment processes. With 75% of wastewater treatment works serving populations of less than 2,000, low-energy tertiary treatment options suitable to small rural works need to be developed. One option that lends itself particularly well to small works is land-based wastewater treatment (LBWWT). The aim of this research was to evaluate the role of LBWWT in the UK water industry and investigate the impact ridge-and-furrow enhanced microtopography (MT) may have upon a particular type of LBWWT - slow-rate (SR) infiltration. This was achieved through meeting three objectives. Firstly, the use of LBWWT was reviewed and assessed. Secondly, the impact of ridge-and-furrow enhanced MT upon the vegetation diversity and nutrient removal of a SR- LBWWT was established by means of a three year field trial. Finally, the cost- effectiveness of SR-LBWWT and the impact of ridging and furrow irrigation upon cost-effectiveness were evaluated using Cost-Effectiveness Analysis (CEA). The first objective comprised of a review of the historical and current use of LBWWT, a review of the relevant changing legislation to identify what may be required of LBWWT and an assessment of LBWWT’s potential to meet these requirements. The result of the evaluation found that, based upon the literature, SR-LBWWT is ‘fit-for-purpose’ as tertiary treatment for small treatment works. To meet the second objective, a SR-LBWWT system trial was established at a small wastewater treatment works in Knowle, Hampshire. The trial consisted of three clay-loam grass plots irrigated with secondary treated effluent. There were two configurations of trial plot - flat and ridge-and-furrowed. Effluent (sub- surface soil water) nutrient concentrations were monitored as was vegetation diversity. In addition a number of physical, hydrological and biogeochemical parameters were monitored and hydrological modelling carried out. Mean nutrient removal performances of 90% for ammonia, 72% for nitrate, and 91% for phosphate were observed with the ridge-and-furrowed plot. Ridging and furrow irrigation was found to not have a significantly detrimental effect upon the trial plots’ removal performance for ammonia, nitrate or phosphate. Extrapolation modelling suggested, however, that this would not be the case for LBWWT systems on predominantly clay or sand soils. Ridging and furrow irrigation was found to have a statistically significant positive effect upon the vegetation diversity of the LBWWT trial plots; with mean final year Shannon-Wiener values of 0.96 and 0.69, for the ridge-and-furrowed and non-ridged plots, respectively. For the final objective, analysis found that SR-LBWWT are cost-effective when compared to horizontal sub-surface flow constructed wetlands (HSSFCW), an established low-energy treatment option. Mean cost-effectiveness ratio values of £208.5 and £262.7 per % effectiveness were observed for LBWWT and HSSFCW, respectively. Following the field trial CEA was extended to include ridge-and-furrowed SR-LBWWT systems. This found that ridging and furrow irrigation improves the cost-effectiveness of SR-LBWWT serving small populations, reducing the mid cost-effectiveness ratio to £193 per % effectiveness. This is a result of the cost-reducing effect of ridge-and-furrowing over laser-level grading; and based upon the findings of the trial that ridging and furrow irrigation can be achieved (in clay-loam soil slow-rate systems) without significant detriment to the water treatment effectiveness of LBWWT. The main conclusions of this thesis are: that SR-LBWWT has a role to play in the UK water industry, as tertiary treatment for small wastewater treatment works. That SR-LBWWT is cost-effective in relation to HSSFCW. That ridging and furrow irrigation increases that cost-effectiveness by reducing the construction and operational costs. That ridging and furrow irrigation can be employed without significant detriment to a SR-LBWWT system’s water treatment performance. And finally, that ridging and furrow irrigation can have a positive impact upon the establishment vegetation diversity of a SR-LBWWT system.

Submitted by MARIO EDUARDO PARDINI AFFONSECA null (maffonseca@sabesp.com.br) on 2016-09-01T12:36:30Z No. of bitstreams: 1 AVALIAÇÃO DA VIABILIDADE E APLICABILIDADE DE MACRÓFITAS AQUÁTICAS PARA POLIMENTO DE EFLUENTES DE ESTAÇÕES DE TRATAMENTO DE ESGOTO DOMÉSTICO – ESTUDO EM ESCALA REAL.pdf: 3194598 bytes, checksum: e3edf2274f08875920b89c8124a090df (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-09-02T13:31:08Z (GMT) No. of bitstreams: 1 affonseca_mep_me_bot.pdf: 3194598 bytes, checksum: e3edf2274f08875920b89c8124a090df (MD5) / Made available in DSpace on 2016-09-02T13:31:08Z (GMT). No. of bitstreams: 1 affonseca_mep_me_bot.pdf: 3194598 bytes, checksum: e3edf2274f08875920b89c8124a090df (MD5) Previous issue date: 2016-07-04 / Vários estudos já foram realizados no Brasil, a grande maioria em escala de bancada, para avaliação da eficiência de remoção de nutrientes através do uso de macrófitas, atestando a sua viabilidade técnica. Os sistemas de tratamento de esgoto doméstico por lagoas não removem fósforo e nem a amônia, o que tem gerado uma série de problemas para atendimento às exigências legais brasileiras para a qualidade de corpos d’água que recebem esses efluentes. Além disso, o excesso de nutrientes ocasiona problemas ambientais que podem inviabilizar outros usos para esses recursos naturais. A ampla disseminação da tecnologia de tratamento por lagoas de estabilização se deu pelo baixo custo de implantação e operação, e pelos bons resultados para a remoção de parâmetros até o nível secundário. Portanto, o país possui um passivo ambiental significativo, o qual requer melhorias para que se ajuste à realidade que se busca alcançar com as restrições pelos órgãos ambientais e pelo arcabouço legal atualmente existente. Neste trabalho foram realizadas duas baterias de testes em escala real na Lagoa da Estação de Tratamento de Recreio, no Município de Charqueada, SP. Os testes foram feitos em dois períodos sazonais completamente distintos, e demonstraram que as variáveis ambientais como radiação solar, ventos e chuvas exercem influencia direta na capacidade de desenvolvimento e remoção de nitrogênio e fósforo para o grupo de macrófitas Lemnaceae, que se encontrava naturalmente instalado nesse sistema. Apesar disso, os resultados obtidos foram muito promissores, chegando a remoções médias de 75% para ambos os parâmetros, sendo os melhores resultados pontuais obtidos para a amônia. Outras constatações evidenciam a necessidade de aprofundamento quanto a melhor forma e periodicidade de manejo, considerando que não pode ser realizada retirada única com o risco de diminuir a capacidade de competitividade dessa macrófita com as algas, que também geraram impacto negativo nas remoções. Após essas constatações, foi realizado um estudo de viabilidade econômica, onde a alternativa de remoção de fósforo total por macrófitas considerou a mão-de-obra, periodicidade e destinação, com o diferencial de que a Companhia de Saneamento Básico do Estado de São Paulo adquiriu em 2013 um equipamento de baixo custo que permite compostar a massa retirada com o lodo do esgoto e dar uma destinação agrícola ao material final. O Valor Presente Líquido (VPL) foi positivo quando comparado à alternativa de implantar um sistema anexo à lagoa instalada, apenas para polimento; e comparado à implantação de um sistema compacto com remoção físico-química. Ambos os estudos foram analisados apenas para sistemas para remoção de fósforo total (PT), e não considerou a remoção de amônia. / Several studies have been conducted in Brazil, the vast majority in bench scale to evaluate the nutrient removal efficiency through the use of macrophytes, attesting to their technical feasibility. Domestic wastewater treatment systems for ponds do not remove phosphorus neither ammonia, which has generated a number of problems to meet the Brazilian legal requirements for the quality of water bodies receiving these effluents. Furthermore, the excess of nutrients causes environmental problems that may prevent other uses for these resources. The wide spread treatment technology by stabilization ponds was due to the low cost of deployment and operation, and the good results for the removal of parameters to the secondary level. Therefore, the country has a significant environmental liability, which requires improvements to fit the reality that seeks to achieve with the restrictions by environmental agencies and the currently existing legal framework. In this work were two full-scale test batteries in the Lagoon Recreational Treatment Plant in the Municipality of Recreio, SP. The tests were done in two completely different seasonal periods, and demonstrated that environmental variables such as solar radiation, wind and rain have a direct influence on the development capacity and nutrient removal for macrophyte group Lemnaceae which found itself naturally installed on this system . Nevertheless, the results were very promising, reaching mean removal of 75% for both parameters, with the best results obtained for specific ammonia. Other findings highlight the need for further development as the best way and management basis, considering that can not be performed only withdrawal at the risk of reducing the competitiveness capacity of water lettuce with algae, which also generated a negative impact on removals. Following these findings, a study was conducted of economic viability, where the alternative removal by macrophytes considered the hand labor, timing and allocation, with the difference that the Basic Sanitation Company of the State of São Paulo acquired in 2013 one low cost equipment that allows the compost mass withdrawal with sewage sludge and to an agricultural destination to the final material. The NPV was positive when compared to the alternative of deploying an attachment system the installed pond, only for polishing; and compared to the deployment of a compact system with physico-chemical removal. Both studies were analyzed only for systems for removal of PT and did not consider the removal of ammonia.

Submitted in fulfilment of the requirements of the degree of Master of Technology: Biotechnology, Durban University of Technology, Durban, South Africa, 2014. / Wastewater treatment plants (WWTPs) frequently experience bulking and foaming episodes, which present operational challenges by affecting sludge settling due to the excessive proliferation of filamentous bacteria. Various control strategies have been implemented over the years to minimize filamentous growth, however, filamentous bulking still remains an unresolved problem in many WWTPs worldwide. The current study focused on developing and optimizing remedial measures viz., specific and non-specific methods to reduce problematic filamentous bacteria in a full-scale WWTP. Specific methods demonstrated the influence of plant operational parameters viz. chemical oxygen demand, influent N-NH4+, food to microorganism ratio, dissolved oxygen, temperature and pH on the abundance of filamentous bacteria. A cumulative logit model was used to determine the significant relationships between the individual filamentous bacteria at present and the prevailing plant operational parameters. Using the above statistical approach, significant observations and predictions were made with respect to the individual filamentous growth under certain operational parameters. With further validation, this model could be successfully applied to other full-scale WWTPs identifying specific parameters that could contribute to filamentous bulking, thus providing a useful guide for regulating specific filamentous growth. Non-specific control methods such as chlorine, ultraviolet irradiation and ozone treatment were investigated on filamentous bacteria using a live/dead staining technique. To achieve at least 50% reduction of filamentous bacteria, a chlorine dose of 10 mg Cl2/L was required, all filaments were killed at a dose of 22 mg Cl2/L. In addition, an effective UV and ozone dose of 4418.91 μw seconds/cm2 and ±20 mg O3/L respectively, was required to kill 50% of the filamentous bacterial population. Among the three non-specific methods, ozone treatment seemed to be an effective method in controlling the filamentous population with a low negative impact to the surrounding environment. This study serves as a useful guide on the problems and control of filamentous bulking in activated sludge plants. / M

Aerobic granular sludge (AGS) technology is a next-generation technology for the biological treatment of wastewater. The advantages of AGS in terms of small footprint, low operation and capital cost and high effluent quality makes it a strong candidate for replacing conventional biological wastewater treatment based on activated sludge (CAS) process, and potentially become the standard for biological wastewater treatment in the future. Saline wastewater is generated from many industrial processes as well as from the use of sea water as a secondary quality water for non-potable use such as toilet flushing to mitigate shortage of fresh water in some coastal cities. Salt is known to inhibit biological wastewater treatment processes in terms of organic and nutrient removal. In the first part of my dissertation, I conducted three lab-scale experiments to 1) evaluate the effect of salt on granulation and nutrient removal in AGS (330 days); 2) develop engineering strategies to mitigate the adverse effect of salt on nutrient removal of AGS (164 days); and 3) compare the effect of salt on the stoichiometry and kinetics of different phosphate accumulating organisms (PAO) clades (PAOI and PAOII) and to determine the effect of potassium and sodium ions on the activities of different PAO clades (225 days). Like other artificial microbial ecosystems (e.g. CAS plant and anaerobic digester), a firm understanding of the microbial ecology of AGS system is essential for process design and optimization. The second part of my dissertation reported the first microbial ecology study of a full-scale AGS plant with the aim of addressing the role of regional (i.e. immigration) versus local factors in shaping the microbial community assembly of different-sized microbial aggregates in AGS. The microbial communities in a full-scale AGS plant in Garmerwolde, The Netherlands, was characterized periodically over 180 days using Illumina sequencing of 16S ribosomal RNA amplicons of the V3-V4 regions. Overall, the discovery of this PhD study sheds light on the application of AGS for the treatment of saline wastewater and deepens our understanding on the microbial ecology of AGS systems, which is essential for process design and optimization.

Content: Wastewater from tanneries besides having toxic compounds also contain nutrients such as carbon, phosphorus, and nitrogen, which facilitate the rapid multiplication of microalgae. Currently, many types of researches search microalgae capable of growing in industrial effluents, exploiting the advantages of removing the nutrients present in these waters and producing biomass with high value- added. The liquid effluents produced in tanneries for finished leather have essential nutrients for the growth of microalgae, but also some compounds that may restrict or hinder the growth of microalgae in this medium. Therefore, the present work has the objective to evaluate the growth of a microalgae consortium (collected in a wastewater treatment plant of a beamhouse tannery) for the removal of phosphorus and ammonia from wastewater streams of a tannery (processing wet-blue to finished leather) with different photoperiods. Microalgae consortium was cultivated at two different compositions of mixtures of raw wastewater (R) and wastewater after secondary biological treatment (B): 50% of R + 50% of B, (50R50B) and 75% of R + 25% of B, (75R25B), in photoperiod of 24 hours and 12 hours of light, temperature of 25 °C and constant aeration. The growth of microalgae in the effluent and the removal of phosphorus and ammonia were monitored throughout the cultivation. The microalgae consortium presented maximum biomass concentrations in the 75R25B effluent (1.40 g L-1) and phosphorus removal (97.64% for the 50R50B and 95.54% for the 75R25B) effluent and ammonia removal (100%) for both effluent with 24-hour photoperiod light. Take-Away: In this study, it was found that the microalgae consortium can survive in wastewater from tanneries (processing wet-blue to finished leather) and exhibit removals of phosphorus and ammonia from the medium. The 24-hour light photoperiod presented better microalgae growth and nutrient removal results.

Replacing the lost Phosphates from different ecosystems is not a question it’s an onus. This none replaceable and renewable resource is one of the vital nutrients where without it, cells, crops and human beings cannot function and live. Though available in environment, its natural cycle is disturbed as its need especially in agriculture sector increases significantly. Phosphorus recovery from waste water sorbents is one of the innovative and promising concepts. The core goal of this paper is to evaluate the phosphorus desorbing capacity of two reactive materials (waste water sorbents) using chemical extracts. The experimental work emphasized on investigation four extracts, HNO3, NaHCO3, P-AL and H2O on phosphate desorption capacity of two inorganic reactive materials namely Polonite® and Sorbulite® which are widely known for their high P-sorption capacity. The kinetics and desorption were examined in batch experiments and consequently the plant availability were investigated using Flow Injection Analyzing (FIA) spectroscopy (wet chemistry) method. The maximum average orthophosphate desorption at 100 rpp for 48 hrs was interpreted to be 33.12 mg g−1and 3.11 mg g−1 from Sorbulite® and Polonite® respectively using 4M HNO3 extract. The orthophosphate desorption characteristic using the above extracts tended to decrease in the following order HNO3 ≤ P-AL ≤ NaHCO3 ≤ H2O. Polonite® shows a higher recovery potential, where almost 6 times higher ammonium lactate (AL)-extractable P was observed when compared with Sorbulite®. Batch experiment was proved to be a tool for investigating and evaluating Phosphorus desorption capacity of mineral-based filter materials.

The laboratory-scale University of Cape Town (UCT) process was designed to investigate the effects of changing COD/TP ratios on the performance of biological nutrient removal (BNR) processes. Specific objectives of the research were to investigate the effects of COD/TP ratio on the rates of phosphorus removal, COD removal, nitrogen removal, PHB utilization and oxygen uptake. The system was fed with municipal wastewater and operated at 20° C. The influent COD concentration was held approximately constant while the phosphorus concentration was varied to obtained the desired COD/TP ratio. Once robust enhanced biological phosphorus removal (EBPR) has been established, the COD/TP ratios of 20, 30, 40 and 60 were investigated. The COD/TP ratio of the influent wastewater was observed to have a substantial effect upon the performance of the UCT BNR system. The amount of phosphorus removed by the system and the percent phosphorus in the aerobic zone MLVSS decreased as the COD/TP ratio increased. In addition, the amount of phosphorus released in the anaerobic zone per unit of COD removed in the anaerobic zone increased as the COD/TP ratio decreased. From this research, the amount of anaerobic COD removal required to remove 1 mg/L of phosphorus in the aerobic zone approached a minimum value as the COD/TP ratio decreased. It was also shown that PHB production increased as the COD/TP ratio increased. The highest specific oxygen uptake rate was always observed in the second aerobic reactor and tended to increase as the COD/TP ratio increased. However, the changes in the COD/TP ratio did not significant affect COD removal, nitrogen removal and the observed yield coefficient, but did strongly affect the MLSS concentration. The MLSS concentration at the COD/TP ratio of 60 was only 55% of that at the COD/TP ratio of 20. A high level of anaerobic COD removal, an elevated percent phosphorus in the waste activated sludge (WAS) and a high soluble effluent phosphorus concentration can be used as indicators that the system is operating under COD limiting conditions. Several phenomena were also observed during this research. Firstly, the performance of the UCT BNR system for EBPR was greatly enhanced by reducing the aerobic volume. Secondly, the correlation between non-oxic phosphorus release and the aerobic phosphorus uptake improved when anoxic phosphorus release was taking into consideration. This indicated that the anoxic phosphorus release was not secondary release once the aerobic zone volume was reduced. Finally, no denitrification was observed in the aerobic zone from this study, based on the assumption that 12% of nitrogen was required for bacterial growth. / Master of Science

Use of switchgrass (Panicum virgatum L.) as a forage and feedstock species requires knowledge of fertilizer application rates and harvest timing to optimize yield and quality. Three experiments were conducted at the Brown Loam Branch Experiment Station, Raymond, MS to quantify nitrogen rates, harvest timing, and genotype effects on biomass, nutrient removal, chemical composition and ethanol yield. Dry matter yield varied with N rate, genotype, harvest frequency and timing. Yields among genotypes were: NF/GA992 = NF/GA001 (13.7 Mg ha-1) > Alamo (11.6 Mg ha-1) > Cave-in-Rock (6.1 Mg ha-1). A single (9.5 Mg ha-1) or two harvests annually (10.3 Mg ha-1) produced the greatest dry matter yield. As harvest frequency increased from three (7.3Mg ha-1) to six (5.9 Mg ha-1) harvests annually, yield decreased. There was an effect of N application on yield, but not at application rates greater than 80 kg ha-1. Nitrogen did not consistently affect tissue nutrient concentrations but more frequent harvests led to increased nutrient concentration. Nutrient removal responses to N application were mostly similar to the yield responses. Nitrogen use efficiency and recovery declined as N rate increased. Estimated ethanol yield averaged 162 L Mg-1 for Alamo, NF/GA001 and NF/GA992 . A single (2.4 kL ha-1) or 2 harvests annually (2.3 kL ha-1) produced the greatest ethanol production and was correlated with by biomass yield. Nutrient removal, N use efficiency, N recovery and ethanol production were related to biomass yields rather than chemical composition differences. The findings in this dissertation will enable a database on management effects on ethanol yield and composition, enhance current biomass models, facilitate improved management of feedstock production inputs and improve feasibility of alternative fuel development.

This research entails the investigation of the effects of a bioaugmentation product from BiOWiSH® called Aqua, referred to as “Aqua” for the remainder of this paper, on the nitrogen removal rate in a membrane aerated bioreactor (MABR). This research was conducted using a MABR design that consisted of a silicone membrane and continuous flow airline with compressed air. The membrane system was designed to supply oxygen, creating an aerated layer at the membrane-biofilm interface and an anoxic layer at the biofilm-water interface. Laboratory experiments were conducted to compare the nitrogen removal rates of natural bacteria alone to natural bacteria paired with Aqua. However, it was not possible to determine if a difference existed between the nitrogen removal rates of the MABR systems with only natural bacteria versus those with natural bacteria augmented with Aqua. The mean nitrogen removal rate observed when the media in the system reached steady state was 0.39 mg-N/L-hr. with a carbon to nitrogen (C: N) ratio of 12:1. The only increase in the nitrogen removal rate observed was when the C: N ratio was doubled to 24:1 and the nitrogen removal rate increased to 0.56 mg-N/L-hr. Although it appeared that the Aqua did not have an influence on the nitrogen removal rate in the MABR systems, many other variables still need to be assessed to reach a conclusion. To improve the efficiency of the system more tubing should be added, or the glucose should be removed from the growth media because the maximum O2 mass transfer rate is only enough O2 for nitrification. The addition of glucose at 12:1 ratio increased the O2 demand in the system to be five times greater than the O2 supplied from the silicone tubing. This research determined that use of trace minerals, Aqua dosing method, and Aqua dosing concentration were not contributing factors in nitrogen removal from growth media under the conditions of this experiment.