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Nitrogen pollution is a growing problem that is detrimental to the environment and the economy. Traditional treatment of nitrogen is a multi-stage process, expensive, operationally intensive, and requires large land areas. This research studied the effects of BiOWiSH® Aqua (Aqua), a biological enhancement product, on the simultaneous nitrification and denitrification process in a membrane aerated bioreactor (MABR) to determine if it is a feasible application for wastewater treatment. The MABR used during experimentation was a small-scale batch reactor with a continuous flow of air through a silicone membrane. The effect of carbon source and concentration on nitrogen removal rates and biomass growth/behavior were determined through a series of laboratory experiments with Aqua and wastewater. With glucose and solely Aqua cultures, average reduction rates in nitrogen concentrations were 1.2 mg-N/L/hour for all C:N ratios investigated. When wastewater was used as the main carbon source, creating a mix of wastewater and Aqua bacteria in the MABR, average reduction rates were 10.9 mg-N/L/hour. A maximum reduction rate of 21.3 mg-N/L/hour occurred at a 2:1 C:N ratio. This research concluded that pure Aqua cultures are not efficient at removing nitrogen or greatly augment the nitrogen reduction process. MABRs can use the biochemical oxygen demand in wastewater as a useful/viable carbon source. High carbon to nitrogen ratios (C:N ratio of 30:1) did not result in faster nitrogen reduction rates but did experience rapid biofilm growth and death. This shows that high C:N ratios are not an efficient operationally for MABRs due to the excess sludge created. C:N ratios of v approximately 3:1 provided the most consistent nitrogen reduction for both glucose and wastewater. This research concluded that C:N ratios, pH, and oxygen diffusion heavily affect the MABR’s performance. In addition, MABRs can utilize low C:N ratios during treatment, particularly during the treatment of high-strength wastewater.

The goal of this case study was to investigate the behavior of real textile wastewater in DCMD (Direct Contact Membrane Distillation) treatment and subsequently to develop a simple and effective pretreatment for it. To this moment, this work is one of the only studies to make an in-depth analysis of the treatment while considering the complexity of this effluent, which is inherently composed of Volatile Organic Compounds (VOCs) and surfactants. After the application of pretreatment, it became clear that the main concern with textile wastewater treatment using MD is wetting, not fouling. Sedimentation and filtration alone were effective in removing suspended solids, but insufficient in stopping wetting. However, neutralization before sedimentation and filtration was proven to be a fundamental step in reducing wetting rates. This improved performance happens due to the change in pH of the wastewater sample, which increases the rejection rates by the membrane. The best experiments, neutralized to pHs 7.40 and 9.06, achieved up to 99.89% rejection by the membrane, with up to 97% conductivity decrease when compared to an experiment without neutralization, 97% removal of COD, and 98% TOC. Overall, the permeate obtained in this work after pretreatment demonstrated excellent quality, and the recovered effluent can possibly be reused in the textile industry, aiming for Zero Liquid Discharge (ZLD) processes. Thus, scaling up this technology for real industrial use is still necessary, tailoring the treatment to the effluent's characteristics to obtain the best results.

Microalgae have been in the center of research for several years due to their high production rates. The use of fresh-water algae in the production of biofuels coupled with wastewater treatment has become a topic of modern research. While most algal farming is performed in warm and sunny climate, this project focused on naturally occurring microalgae in Northern Sweden and their ability to reclaim wastewater and produce lipids. The four microalgae Chlorococcum sp. (MC1), Scotiellopsis reticulata (UFA-2), Coelastrella sp. (3-4) and Chlorella vulgaris (13-1) were grown under mixotrophic conditions in municipal wastewater (MWW), pulp and paper wastewater (PnP) and mixtures of both. Except of UFA-2, I found the growth of the tested species to be limited in pure PnP, however, mixtures of PnP and MWW were suitable for algal growth. The removal rates of total nitrogen achieved the goals regulated by the Swedish government for wastewater reclamation. Phosphorus, of which maximal levels according the Swedish regulations need to be below 0.5 mg/L, was efficiently removed by the strain 3-4 in PnP and in MWW + PnP (ratio 3+1) as well as by the strain 13-1 in MWW + PnP (ratio 3+1). The tested microalgae are therefore appropriate candidates to be used in sustainable wastewater treatment. The algal biomass composition was determined with the help of Fourier-transform infrared spectroscopy and an increase in the spectra for biomass grown in wastewaters within the fingerprint region (800 – 1800 cm-1) was observed. From this, I conclude that the lipid content was elevated in the biomass received after growth in PnP and all mixtures of MWW and PnP compared to the in BG11 grown biomass, which acts as a control group. A quantitative lipid analysis performed on the biomass of the strains UFA-2 and 3-4 confirmed higher lipid amounts after growth in PnP wastewater compared to growth in BG11. These findings show that the examined microalgae might have the potential to be used as a potential feedstock for biofuel productions after cultivation in local wastewaters.

pH control is a tool to improve some aspects of Enhanced Biological Phosphorus Removal (EBPR) process. Filipe et al (2001a, 2001b, and 2001c) found strong evidence that the stability of EBPR systems can be improved by increasing the pH of the anaerobic zone, thereby creating conditions where phosphorus-accumulating organisms (PAOs) are able to take up acetate faster than glycogen-accumulating organisms (GAOs). They explained this observation by comparing the growth rate of phosphorus-accumulating organisms (PAOs) and glycogen-accumulating organisms (GAOs) and found that pH has little effect on PAOs growth rate but adversely affects GAOs growth rate when it increases (at pH values greater than 7.25, PAOs would take acetate faster than GAOs would). They used synthetic wastewater rich in acetic acid. In this study, we used real wastewater and the dominant volatile fatty acid available to microorganisms was propionic acid in continuous EBPR system. It was found that lower anaerobic zone pH (6.5 vs. 7.2) reduced the anaerobic P release both on an MLVSS specific basis and also on a non-specific (absolute value for the process) basis. In addition, the observed yield was significantly decreased. Aerobic P uptake was lower in the low-pH system (on a non-specific basis) due to the lower observed yield, and thus lower MLVSS concentration. Net P uptake was hard to interpret because of the effect of P release in the secondary clarifier of Train 2 (high pH). However, on a specific basis it was clear that net P uptake was either equal or better in the low-pH system regardless of how the secondary clarifier data was interpreted. Carbon transformations were not impacted in as consistent a fashion as anaerobic P release was. On a specific basis, PHA content remained unchanged although the PHV/PHB ratio was impacted with much lower PHV content in the low-pH system. Glycogen content and the amount of labile glycogen (delta glycogen) were higher in the low-pH system, in spite of the fact that MLVSS P content did not decrease. However, due to the impact of the low observed yield at low pH, absolute values resulted in higher PHA content for the process reactors as a whole, higher glycogen content, and unchanged labile glycogen. Low pH resulted in increased biomass P content, however the lower observed yield offset this on a process basis so that effluent P levels were nearly equal. So low pH improved P removal on a specific basis, but not on a process basis. Since it is unknown if the low observed yield is repeatable, and due to the impact of the secondary clarifier in the high pH system, it cannot be concluded that the effect of low pH on net P removal would be similar in other EBPR systems.

Abstract Investigation of a Commercial Product (BiOWiSH­­TM) for Nitrogen Management Eva Lee BiOWiSH–Aqua, which has the capability of treating nitrogen from wastewater through bioaugmentation, is a commercial product consisting of a blend of microorganisms developed by BiOWiSH Technologies. A study of the treatment of nitrogen compounds (i.e. , , and ) using Biowish–Aqua was conducted using small scale experiments (flask experiments) and large scale experiments (column reactor experiments). In this work, column reactors were created to test Biowish–Aqua’s nitrogen treating capabilities by providing enough depth to simulate the dissolved oxygen gradient that can be observed in a pond. The results show that the optimal growth conditions for both ammonia assimilating and denitrifying bacteria are an anoxic environment with a carbon-to-nitrogen ratio of 2:1. Under this optimal growth environment, Biowish–Aqua was able to assimilate ammonia with a zero order k value of 3.06 ppm/day. Also, under the same conditions, Biowish–Aqua was able to eliminate nitrate ( ) and nitrite ( ) at a rate of 9.58 ppm/day and 5.64 ppm/day respectively. The experiments also suggested that with a C:N ratio of 2:1, Biowish–Aqua did not have an effect in slowing the hydrolysis of urea. Overall, this research suggests that the application of Biowish–Aqua is a feasible nitrogen removing strategy for wastewater with initial presence of ammonia and nitrate between 10 to 20 ppm. Keywords: Ammonia assimilation, Bioaugmentation, BiOWiSH, Denitrification

This thesis explores the treatment of municipal wastewater using pilot-scale raceway ponds and looks specifically at the capability of the raceways in removing BOD and nitrogen. Nine 33 square-meter algal raceway ponds were used to conduct research at the San Luis Obispo Water Resources Recovery Facility. Main objectives of this study were to increase the removal of total ammonia nitrogen (NH3-N plus NH4+-N) from municipal wastewater through increased assimilation and nitrification. Raceway ponds with CO2 addition were operated in series with an intermediate settling step and a total hydraulic retention time (HRT) of 4 days to measure the increase in nitrogen removal through assimilation by two rounds of algae growth. A single round of treatment with a 4 day HRT was also operated and compared to the two rounds. The two rounds of treatment and 1 round of treatment removed on average 36.6 mg-N/L and 35.2 mg-N/L of TAN, with respective standard deviations of 6.3 mg-N/L and 5.3 mg-N/L. No statistical significant difference was found between two treatment methods for TAN (mg-N/L) removal (t = -0.64, DF = 23.3, P =0.28), % TAN removal (t = -1.18, DF = 22.6, P = 0.25), and TAN (mg-N/L) of final effluent (t = 1.11, DF = 23.6, P = 0.28). Raceway ponds were aerated at night to keep nighttime DO from dropping to concentrations inhibitory to nitrification. The rates of nitrification with night aeration were measured. The nitrification rates were compared to a model based on Monod kinetics. The Monod model did not correspond with performance results of ponds.

In conventional wastewater treatment, biological nutrient removal (BNR) depends on bacterial assimilation for phosphorus removal and nitrification+denitrification for nitrogen removal, with the resulting loss of the fixed nitrogen resource. Alternatively, treatment by microalgae allows for assimilative removal of both phosphorus (P) and nitrogen (N) thereby avoiding the oxygen demand of nitrification and preserving fixed N for fertilizer use. Paddle wheel mixed high-rate ponds have much higher algal productivity than typical oxidation ponds, but even high-rate ponds often cannot grow sufficient algae to completely assimilate the N and P in domestic wastewater. Algae growth in high-rate ponds is usually limited by the inorganic carbon concentration. Addition of carbon dioxide to high-rate ponds, for example from flue gas, eliminates this limitation and accelerates algae growth and nutrient assimilation. This laboratory study explored the extent to which soluble N and P are removed simultaneously by CO2-enriched algae cultures. Algal polycultures were grown on diluted domestic wastewater media that were manipulated to obtain a wide range of N:P ratios (2.5:1 to 103:1). In addition, two levels of trace metal concentrations were studied. Media feeding was semi-continuous. The variables monitored included N and P removals, the range of N:P ratios in the algal biomass, biomass production, and alkalinity. To achieve removal of total N and P, suspended solids also must be removed prior to discharge. Since flocculation and settling is a preferred method of algae removal, the effects of low dissolved nutrient concentrations and media composition on algae sinking potential (settleability) were also investigated. The low trace metal cultures achieved >99% total ammonia nitrogen (TAN) removal for N:P ratios 2.5 through 30 and >98% dissolved reactive phosphorus (DRP) removal for N:P ratios 2.5 through 60 (with one exception at N:P-20). This removal was due to the growth of 180-500 mg/L algal volatile solids. Effluent concentrations were <0.1 mg/L TAN for N:P 2.5 through 30, and <0.5 mg/L TAN for N:P-60. DRP effluent concentrations were ≤0.02 mg/L DRP. After 24 hours of settling in beakers, nearly all cultures had total suspended solids (TSS) concentrations <40 mg/L. Alkalinity consumption increased with increasing N:P ratios. For cultures with the higher trace metal concentrations, nutrient removal was similar: >96% of TAN and >95.9% DRP removal for all N:P conditions. However, settling with these media was poor. TSS concentrations after 24-h of settling were >100 mg/L. No clear relationship for alkalinity was found for these cultures. N:P ratios in the algal biomass correlated with the N:P ratios in the media, except for control cultures that did not receive wastewater. No relationship was found between settling and the N:P ratios of the media or biomass. Nitrogen-fixing algae thrived in media containing N:P ratios of 2.5:1 and 5:1. Algae were found to be plastic in their cellular N:P ratios (4.6 to 63, with wastewater media) which allowed them to simultaneously remove both dissolved N and P to low levels, while growing settleable biomass. These results indicate that CO2-enriched high rate pond systems would be useful in simultaneously removing N and P from wastewaters with a wide range of N:P ratios.

Overfishing of natural fisheries is a global issue that is becoming more urgent as the human population increases exponentially. According to the Food and Agriculture Organization of the United Nations, over 70% of the world's seafood species are fully exploited or depleted. This high demand for seafood protein is not going away; and, in fact, an astonishing one out of five people in this world depend on this source of protein. Traditional aquaculture practices use pond and flow-through systems which are often responsible for discharging pollutants into the environment. Furthermore, aquacultural feeds often contain high levels of fish protein, so the demand on wild fisheries is not completely eased. Even though traditional aquaculture has these drawbacks, there is a significant movement towards more sustainable practices. For example, implementing recirculating aquaculture systems (RAS) maximizes the reuse of culture water which decreases water demand and minimizes the levels of pollutants being discharged to the environment. And, alternative proteins (e.g., soy bean) are replacing the fish and seafood proteins in aquaculture diets. Accordingly, the research described in this dissertation focused on maximizing the reuse of freshwater fish effluent to culture marine shrimp. More specifically, by using suspended-growth biological reactors to treat a tilapia effluent waste stream and to generate microbial flocs that could be used to support shrimp culture. This RAS technology will decrease water consumption by increasing the amount of recycled water and will also improve effluent water quality. The biomass generated in the bioreactors could be used to feed shrimp with an alternative source of protein. Treating fish effluent to be reused to culture shrimp while producing this alternative feed, could significantly decrease operational costs and make these operations more sustainable. Understanding which ions are critical for the survival and normal growth of marine shrimp in freshwater effluents is essential. It is also very important to understand how to convert an effluent's organic matter into food for shrimp. Results from studies revealed that the marine shrimp, Litopenaeus vannamei, can be raised in freshwater effluent when supplemented with specific ions and wet microbial flocs fed directly to shrimp can enhance growth in shrimp fed a restricted ration of commercial feed. The treatability of the tilapia effluent using suspended-growth, biological reactors and nutritional analysis of the generated biomass were also reported. Carbon supplementation enhanced reactor performance and microbial floc generation. These microbial flocs also proved to be a superior feed ingredient when dried and incorporated into a pellet feed. / Ph. D.

The biological treatment of wastewaters from an industry was studied. Among the more important wastewater constituents of concern were high levels of suspended solids, due to graphite and nitrocellulose, the solvents, ethanol and acetone, and nitroglycerine (NG). The goal of this project was divided into four objectives. The impacts of graphite on a microbial population were evaluated. Sequencing batch reactors (SBRs) were used to monitor the effects of graphite on mixed liquor suspended solids (MLSS), removal of soluble chemical oxygen demand (sCOD), and specific oxygen uptake rates (sOUR). Graphite appeared to have no adverse effect on the microbes. The potential benefits of adding sucrose, nitrogen, and phosphorus to SBRs were evaluated. The MLSS was maintained at 1,250 mg/L, similar to the microbial population in the suspended growth system at the industry. Sucrose addition increased the sCOD removals and sOUR. No direct effect was observed with the addition of nitrogen and phosphorus. The treatability of acetone and ethanol was studied through sOUR and batch testing to determine bacterial response to solvents. Both solvents were utilized by the microbes. The concentrations tested proved to be beneficial, not inhibitory. Ethanol and a 50/50 mixture of acetone and ethanol were more viable substrates than acetone. NG treatability was examined under anoxic and aerobic conditions in SBRs and batch biological reactors. NG degradation occurred under anoxic conditions, but was more favorable in aerobic environments. NG was degraded in all SBR tests to below detection limit (0.5 mg/L); therefore, the optimal treatment could not be determined. / Master of Science