Brominated very short-lived substances (BrVSLS) are atmospherically important trace gases that play an important role in stratospheric ozone destruction. Major BrVSLS including bromoform (CHBr_(3)), dibromomethane (CH_(2)Br_(2)), chlorodibromomethane (CHClBr_(2)), and bromodichloromethane (CHBrCl_(2)) are thought to be predominately formed naturally via vanadium bromoperoxidase (V-BrPO) mediated halogenation of organic matter (OM). The objective of this research was to couple field observations and laboratory experiments to understand global distributions, saturation anomalies, fluxes, and identify natural sources of BrVSLS. All the trace gases were measured with gas chromatography mass spectrometry (GC-MS). Field observations were conducted in the Pacific and Atlantic Oceans. Results from field observations showed that BrVSLS tend to be elevated in biologically active waters, such as coastal waters, the productive surface open ocean, and at chlorophyll maximum depths. The production of natural BrVSLS is likely controlled by complex biogeochemical factors in the ecosystems. CH_(2)Br_(2) was thought to be derived from the same source(s) as CHBr_(3), but results presented in this dissertation suggest they may in fact be derived from disparate sources. Screening for important BrVSLS producers was attempted in the laboratory. Only 2 out of 9 phytoplankton species screened show observable BrVSLS production. CH_(2)Br_(2) production was only observed in 1 species screened. Chloroperoxidase-like activity in diatom was observed for the first time, which provided evidence for biological production of chloroform (CHCl_(3)). The role of dissolved organic matter (DOM) in controlling BrVSLS production was investigated in the laboratory. Production of BrVSLS varied significantly with different model DOM compounds upon V-BrPO mediated halogenation. Certain DOM enhanced BrVSLS production, but the majority of the model DOM compounds tested in this study either interfered with or had no observable effect on BrVSLS production. Further evidences showed that V-BrPO mediated halogenation can alter DOM chemical characteristics. Alteration of colored dissolved organic matter (CDOM) in terms of “bio-bleaching” was observed in model lignin phenol compounds and CDOM collected from two cyanobacterial cultures. Results from this study suggest that the presence of V-BrPO producing phytoplankton is essential for enhanced BrVSLS production, as V-BrPO induced brominated reactive species, such as hypobromous acid (HOBrenz), is required. However, BrVSLS production rates are largely controlled by other biogeochemical factors in seawater, such as DOM composition. Results from this study also suggest that V-BrPO activity not only plays an essential role in BrVSLS production, but it also plays a significant role in the transformation of DOM and may be a significant component of the marine carbon cycle.

Ruminant livestock are a significant contributor to global greenhouse gas emissions, accounting for 6% of total emissions worldwide. Over the past two decades, extensive research has examined the environmental impact of methane (CH4) emissions from these animals. Recent scientific interest has focused on seaweed as a potential CH4 inhibitor, with the compound bromoform identified as the key active component responsible for reducing CH4. A review of the literature, and different mitigation strategies are mentioned in chapter 1 of this dissertation.The second chapter of this dissertation discussed the effects of different bromoform concentration levels on enteric CH4 production and rumen fermentation using 24 h rumen batch culture systems. The doses tested ranged from 0.02 to 13.4 μl bromoform per liter of rumen fluid. The ANKOM batch culture system was utilized, with samples collected after 24 h of incubation for analysis of volatile fatty acids (VFAs) and CH4 levels. Statistical analysis using one-way ANOVA, Student's T-test, and Dunnett's model in JMP Pro revealed a linear reduction in CH4 production as bromoform concentrations increased from 0.02 to 13.4 μl/L (P<0.001). Total CH4 mitigation occurred at doses from 0.20 to 13.4 μl/L (P<0.01), while lower doses of 0.02, 0.05, and 0.10 μl/L reduced CH4 production by 4, 8, and 23% respectively compared to the control (P<0.001). Total VFA concentrations responded quadratically to bromoform treatment. High doses (1.67-13.4 μl/L) caused a reduction in total VFAs (tVFAs), whereas low doses (0.02-0.10 μl/L) had no significant effect. Decreased tVFAs at high doses corresponded with reductions in the molar proportions of acetate and propionate and an increased acetate: propionate ratio (P<0.001). Conversely, low doses decreased the acetate: propionate ratio (P<0.001). Butyrate molar proportions increased across all dose levels (P<0.01).On Chapter 3, we investigated the long-term effects of different doses of bromoform, an active compound from the red seaweed Asparagopsis taxiformis, on CH4 production and rumen fermentation characteristics using a continuous fermenter system. Four treatments were tested - control (no bromoform) and 0.14, 0.27, 0.56 μl/L bromoform doses - in a Latin square design with four 10-day periods. Bromoform doses were divided and dosed with a 50:50 forage: concentrate diet three times daily. Results showed bromoform doses up to 0.56 μl/L reduced enteric CH4 production by 98% compared to control, while increasing hydrogen (H2) concentrations by 550-860% and decreasing ammonia (NH3-N) and pH. Total VFA and dry matter digestibility (DMD) were unaffected, but bromoform altered individual VFA proportions, decreasing acetate, iso-butyrate and acetate: propionate ratio while increasing propionate and butyrate.The withdrawal effect of bromoform was investigated in chapter 4 using four continuous fermenters over two 10-day periods. Treatments were control with no bromoform (T1), bromoform (0.14 μl/L rumen fluid/day) added for the first 5 days (T2), 7 days (T3), or all 10 days (T4) of each period. Bromoform addition reduced CH4 concentrations by 98% and H2 levels compared to control, but these effects nearly disappeared 3-5 days after bromoform dosing ended. The molar proportions of acetate decreased while the molar proportions of propionate increased with bromoform, though these changes were less pronounced 3-5 days post-dosing. Total VFA, NH3-N, and DMD were unaffected by treatment diets. The last chapter of this dissertation discusses the use of Laser Methane Detector (LMD) and Optical Gas Imaging (OGI) for detecting and quantifying enteric CH₄ emissions from ruminants in vitro. Four dietary treatments with varying forage-to-concentrate ratios(F:C) were tested in rumen fermenters. The control treatment (T1) was a 50:50 forage to concentrate diet (F:C), while T2 was the control diet with bromoform added, a known CH4 inhibitor, T3 was a high forage diet (80:20 F:C), and T4 was a low forage diet (20:80 F:C). LMD measurements aligned with the standard gas chromatography (GC) method. Results showed that diet composition significantly impacts CH₄ production: the high-forage diet (T3) produced the most CH₄, while adding bromoform fully inhibited emissions. OGI images analyzed with semantic segmentation models, particularly Gasformer, effectively detected CH₄ plumes. The study concluded that combining OGI with deep learning models can effectively monitor CH₄ emissions to inform dietary and management practices to mitigate climate change. In conclusion, bromoform significantly mitigated CH4 emissions without significantly impairing rumen fermentation however, the effect of bromoform can be reversed with the discontinuation of the treatment suggesting its mode of action is unlikely related to altering the rumen microbial profile. Future research is necessary to evaluate the effect of adding bromoform on feed intake and animal health, and the different aspects of introducing bromoform to the animal feeding industry

A comprehensive survey of the presence of trihalomethane (THM) compounds, as chlorination by-products, in drinking water in Kuwait have been performed. The survey covers the whole drinking water treatment cycle, starting with sea water and ending with the consumer tap. The data generated by the survey was all derived from actual water treatment plants, operating under normal conditions. All four trihalomethane compounds, namely; chloroform (CHCI3), bromodichloromethane (CHBrCI2), dibromochloromethane (CHBr2CI) and bromoform (CHBr3) were covered. The study clearly showed that, although considerable amounts of THM compounds did form as a result of chlorination of sea water entering the multi-stage flash (MSF) distillation plants, these plants were highly efficient in removing these compounds. The average removal efficiency, based on THM compounds mass load in the sea water feed, was around 95%. Factors which were found to have an influence on the degree of formation of these compounds, include, chlorination practice (continuous vs. shock), sea water temperature, level of organic precursors and contact time. Of much more important consequence, as far as the presence of these compounds in drinking water is concerned, was the degree of THM compounds formation as a result of the chlorination of drinking water before it is pumped to the consumer. Here, not only all the compounds formed remain in the water but there is a definite tendency for continuous formation well after the actual chlorination process has taken place. Factors which were found affecting this formation include water temperature, contact time and chlorination dosage. Although, all samples collected showed that the presence of THM compounds was always below the United States Environmental Protection Agency maximum contaminant level of 100 ~g/L, a need exists for the optimization of all chlorination processes with particular emphasis on the chlorination of drinking water. In almost all kinds of water encountered in this study, bromoform was found to be by far the most dominant compound.

Disinfection is an essential process in the treatment of municipal wastewater before the treated wastewater can be discharged to the environment. Hillsborough County's Northwest Regional Water Reclamation Facility (NWRWRF) in Tampa, Florida, currently uses ultraviolet (UV) light for disinfection. However, this method has proven expensive to implement and maintain, and may not be effective if the light transmission is poor. For these reasons, Hillsborough County is considering switching from UV light to sodium hypochlorite for disinfection. However, hypochlorite (chlorine) disinfection has disadvantages as well, such as the production of disinfection by-products (DBPs) such as trihalomethanes (THM) and haloacetic acids (HAAs), which may have adverse impacts on the quality of surface waters that receive the treated wastewater. Therefore, the objectives of this research are (1) to compare NWRWRF typical operating conditions and water quality to those of two nearby facilities (River Oaks and Dale Mabry Advanced Wastewater Treatment Plants) that currently employ chlorine disinfection, (2) to determine the chlorine demand of treated effluent from NWRWRF, (3) to quantify the DBP formation potential of treated effluent from NWRWRF, and (4) to determine the effects of temperature, reaction time, and chlorine dose on chlorine demand and THM formation. To inform laboratory experiments, the quality of final effluent was monitored at NWRWRF and at two nearby wastewater treatment plants that currently use hypochlorite for disinfection. At these two facilities, pH of 7.0-8.0, chemical oxygen demand (COD) of 12-26 mg/L, alkalinity of 200-250 mg/L as CaCO3, chlorine residual of 1.5-6.0 mg/L, and total trihalomethanes of 100-190 ix μg/L (mostly chloroform) were observed. Conditions at NWRWRF were similar to those at Dale Mabry and River Oaks AWWTP, suggesting that chlorine demand and THM formation at NWRWRF would be similar to those at the two AWWTP, if chlorination is to be used. THM experimental results agreed with this suggestion. Chlorine dose and temperature effects on the free chlorine residual and THMs production in NWRWRF filtered wastewater effluent were determined. Filtered effluent was collected and transported to USF laboratory where it was tested for 3 different chlorine doses (6 mg/L, 9 mg/L and 12 mg/L as Cl2) and 3 different temperatures (16°C, 23°C, and 30°C) at 7 different contact times (15, 30, 45, 60, 75, 90, and 120 min) in duplicate. The total number of batches prepared was: 3 different chlorine doses × 3 different temperatures × 7 different reaction times = 126 reactors. According to Florida Administrative code 62-600.440, total chlorine residual should be at least 1 mg/L after a contact time of at least 15 min at peak hourly flow. Also, according to Florida Administrative code 62-600.440, if effluent wastewater has a concentration of fecal coliforms greater than 10,000 per 100 mL before disinfection, FDEP requires that the product of the chlorine concentration C (in mg/L as Cl2) and the contact time t (in minutes) be at least 120. Results showed that free chlorine residual was always above 1 mg/L in 15 min contact time for all chlorine doses and temperatures tested in this thesis. However, to be conservative, thesis conclusions and recommendations were based on the more stringent regulation: C*t ≥ 120 mg.min/L, assuming that the number of fecal coliform in NWRWRF wastewater effluent exceeds 10,000 per 100 mL prior to disinfection. The analysis showed that free chlorine residual for 6 mg/L was below the FDEP standard at all temperatures. At 16 °C and 23 °C, chlorine doses of 9 and 12 mg/L resulted in an appropriate free chlorine residual above the FDEP standard. However, a chlorine dose of 12 mg/L was resulting in high residual, which means high THM would be expected. Therefore, at 16 x and 23°C, 9 mg/L would be preferable. At 30 °C, only the chlorine dose of 12 mg/L met the standard at all contact times. As expected, free chlorine residual decreased with an increase in temperature from 23°C to 30°C. Surprisingly, the residual at 16°C was lower than residual at 23°C. The production of THMs increased with higher contact time in all the experiments completed. Chlorine dose didn't have an effect on THM formation at 23°C, but it did at 30°C and 16°C, where THM concentrations were generally higher with the increase of chlorine dose. Temperature effect was noticed in most of the experiments, where THM production was usually higher at higher temperatures, except some cases where formation was similar for different temperatures. Chloroform, dichlorobromomethane, dibromochloromethane production ranges were respectively: 20-127 μg/L, 18-59 μg/L, and 3-7 μg/L. Bromoform concentrations were not observed in this experiment at any temperature or chlorine dose. According to Florida Administrative code 62-302.530, Criteria for Surface Water Quality Classifications, the Florida Department for Environmental Protection (FDEP) set the following limits for THM concentrations in wastewater effluent to be as the following; 470 μg/L for chloroform, 22 μg/L for dichlorobromomethane, 34 μg/L for dibromochloromethane, and 360 μg/L for bromoform. Experimental results on NWRWRF filtered effluent showed that only dichlorobromomethane exceeded the limits set by FDEP at about 30 min contact time for all temperatures and chlorine doses tested. However, according to Florida Administrative code 62- 302-400, proposed changes to the code have set higher DCBM limit of 57 μg/L. Chlorination would be recommended at NWRWRF if the DCBM regulated limit increases to 57 μg/L. The recommended chlorine dose would be 9 mg/L for water temperatures around 16-23 °C and 12 mg/L for water temperatures around 30 °C

Made available in DSpace on 2014-10-09T12:41:41Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:07:06Z (GMT). No. of bitstreams: 0 / Com a aprovação da Política Nacional de Resíduos Sólidos, a política de sustentabilidade tende ao reaproveitamento de resíduos, em seu ciclo ou destinação final ambientalmente adequada. Neste contexto, são apresentados neste trabalho, estudos do processo de separação de materiais metálicos e não metálicos encontrados em placas de circuito impresso de microcomputadores e a caracterização dos elementos químicos presentes. Para isto efetuou-se a trituração primária (moagem) das placas de circuito impresso, classificação granulométrica, separação de elementos metálicos e não metálicos utilizando separadores, magnético e eletrostático, separação gravimétrica com o uso de clorofórmio e bromofórmio. Para caracterização dos elementos metálicos e não metálicos, foram utilizadas as técnicas de Espectrometria de fluorescência de Raios X e Espectrometria de infravermelho. Os separadores eletrostático e eletromagnético não foram efetivos na separação de placas de circuito impresso para granulometrias inferiores a 9 Mesh. A separação dos elementos metálicos e não metálicos das amostras com granulometrias inferiores a 9 Mesh, teve eficiência parcial utilizando o clorofórmio, mas mostrou-se efetiva com a utilização do bromofórmio. Embora a separação gravimétrica, não tenha sido efetiva, as amostras foram caracterizadas. Para obter uma melhor separação dos elementos presentes na amostra de não metálicos, procedeu-se a trituração secundária (moagem) desta amostra, resultando na desagregação e separação efetiva. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Historically, chlorination has been widely utilized as a primary and secondary disinfectant in municipal water supplies. Although chlorine disinfection is effective in inactivating pathogenic microbes, the use of chlorine creates the unintentional formation of regulated chemicals. On January 4, 2006, the United States Environmental Protection Agency (EPA) promulgated the Stage 2 Disinfectants/Disinfection by-product rule (DBPR) that focuses on public health protection by limiting exposure to four trihalomethanes (THM) and five haloacetic acids (HAA5), formed when chlorine is used for microbial pathogen control. This thesis examines post-aeration TTHM formation when employing spray-aeration processes to remove semi-volatile TTHMs from chlorinated potable water supplies. A bench scale air stripping unit was designed, constructed and operated to evaluate spray aeration for the removal of the four regulated trihalomethane (THM) species from potable drinking water including bromodichloromethane, bromoform, dibromochloromethane, chloroform. The study was conducted using finished bulk water samples collected from two different water treatment facilities (WTFs) located in Oviedo and Babson Park, Florida. Both treatment plants treat groundwater; however, Oviedo's Mitchell Hammock WTF (MHWTF) supply wells contain dissolved organic carbon and bromide DBP precursors whereas the Babson Park WTF #2 (BPWTF2) supply well contains dissolved organic carbon DBP precursors but is absent of bromide precursor. Three treatment scenarios were studied to monitor impacts on total trihalomethane (TTHM) removal and post-treatment (post-aeration) TTHM formation potential, including 1) no treatment (non-aerated control samples), 2) spray aeration via specially fabricated GridBee® nozzle for laboratory-scale applications, 3) spray aeration via a commercially available manufactured BETE® nozzle used for full-scale applications. Select water quality parameters, chlorine residual, and total trihalomethane concentrations were monitored throughout the study. The GridBee® spray nozzle resulted in TTHM removals ranging from 45.2 ± 3.3% for the BPWTF2 samples, and 37.7 ± 3.1% for the MHWTF samples. The BETE® spray nozzle removed 54.7±3.9% and 48.1±6.6% of total trihalomethanes for the Babson Park and Mitchell Hammock WTF samples, respectively. The lower percent removals at the MHWTF are attributed to the detectable presence of bromide and subsequent formation of hypobromous acid in the samples. Post spray aeration TTHM formation potentials were monitored and it was found that the MHWTF experienced significantly higher formation potentials, once again due to the presence of hypobromous acid which led to increases in overall TTHM formation over time in comparison with the Babson Park WTF #2 TTHM formation samples. In addition, chlorine residuals were maintained post spray aeration treatment, and initial chlorine residual and trihalomethane concentrations did not significantly impact overall spray nozzle performance. Among other findings, it was concluded that spray nozzle aeration is a feasible option for the Babson Park WTF #2 for TTHM compliance. For Oviedo's Mitchell Hammock WTF spray aeration was successful in removing TTHMs, however it was not effective in maintaining DBP rule compliance due to the excessive nature of DBP formation in the water samples. This study was not intended to serve as an assessment of varying nozzle technologies; rather, the focus was on the application of spray aerators for TTHM removal and post-formation in drinking water systems.