Browsing by Subject "Water reuse"
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Item Biological treatment of transit mission waste stream(Texas Tech University, 2004-12) Kaparthi, SrikaraThe waste stream on the space mission is recycled to get the potable water. To recover the waste stream, biological (packed-bed and aerated membrane biological reactor) methods are used. Nitrificafion takes place in aerated membrane reactor and denitrification takes place in the packed-bed. The waste stream on space mission is divided into three types based on the technology expected to be available during space missions. The three types of waste streams are transit mission waste stream, early surface mission waste stream, and mature surface mission waste stream. Transit mission waste stream consists of urine, DDI water, and humidity condensate. Little work has been conducted to evaluate the efficiency of the biological treatment of the urine-humidity condensate waste stream. The objectives of this experiment are 50 percent ammonium removal and 95 percent DOC removal. In this experiment four HRTs are used. The objectives of this experiment were met and the performance of the system is not only related to the adequacy of the reactor but also to characteristics of waste stream. Denitrification is limited by DOC and nitrification is kinetically limited. Therefore, to improve the biological treatment efficiency, either DOC or HRT should be increasedItem Comprehensive trade study of bioreactors and advancement of membrane-aerated biological reactors for treatment of space based waste streams(2012-03) Kubista, Kyle; Jackson, Andrew W.; Morse, AudraBiological processes offer an alternative approach to treatment of waste streams for water recycling during long term space missions. The combination of biological pretreatment with downstream physiochemical processes may be able to produce potable water at a lower equivalent system mass (ESM) compared to systems composed of only physiochemical processes. Several biological configurations exist for the removal of carbon and nitrogen. To date, no studies have comprehensively evaluated the relative ESM of each system. The configurations evaluated include: 1) membrane aerated biological reactor for simultaneous nitrification/denitrification, 2) membrane aerated biological reactor for nitrification in sequence with a packed-bed reactor for denitrification and organic carbon removal, 3) a pre-carbon oxidation reactor followed by a membrane aerated biological reactor for nitrification, and 4) an extended membrane aerated biological reactor for nitrification and aerobic carbon oxidation. We report on the systems, analysis and results including a detailed discussion of the inputs of the ESM analysis, methodology for determining reactor size and mass, and the implications of each system on downstream processing and reliability. Ongoing development of microgravity compatible biological reactors is essential to develop full scale flight ready technology. Recently, the first full scale membrane aerated biological reactor (MABR) was developed and evaluated. Despite several shortcomings, the reactor laid the groundwork for future development. To further develop the full scale MABR, a counter-diffusion membrane aerated nitrification denitrification reactor, a new upgraded MABR (CoMANDR) was designed to overcome the limitations experienced by the first generation. The first generation was limited primarily by its ability to transfer oxygen to the bulk liquid and inability to make repairs due to inaccessibility to the various chambers. CoMANDR is designed to overcome oxygen transfer limitations by using a submersible membrane module (SMM) with a pressurized lumen and additional membranes (to provide increased surface area). The SMM has the ability to be completely removed from the bulk liquid chamber allowing for ease of maintenance and repair. Along with the SMM, features like unidirectional gas flow patterns, offset liquid influents, and additional membranes are incorporated into CoMANDR to address the limitations experienced in the first generation. CoMANDR has been designed, constructed and is expected to meet treatment efficiencies of 90 % dissolved organic carbon removal, 70 % nitrification, and 50 % denitrification. CoMANDR will treat mass loadings of 34 g-C/d and 44 g-N/d at a hydraulic loading rate of 40 L/d. The reactors use silicone membranes to provide surface area for bacterial attachment and to supply oxygen to the bacteria. The membranes are the most important feature of MABRs because they provide a unique biofilm stratification that allows for higher removal efficiencies. The counter-diffusion of oxygen and substrate to the bacteria create optimum biofilms. MABR technology has been studied for over 10 years and has recently been designed for full scale applications. The first full scale model experienced oxygen transfer limitations. The next full scale application intends to operate under liquid pressure and lumen pressure (conditions that have not been investigated). This paper investigates benefits of switching to thin walled membranes (1.3 mm thick) from the previously used 2.24 mm thick membranes. The thin walled membranes cannot maintain structural integrity under elevated liquid pressure. Also, the thin membranes only slightly increase the oxygen transfer rate. The thick wall membranes are recommended for the optimization of the new full scale MABR, (CoMANDR).Item Determination of the fate and behavior of an alternative surfactant in a water recycle system (WRS)(Texas Tech University, 2002-12) Rector, Tony JamesThe fate of a common commercial surfactant was investigated in biological reactors intended for long-term space applications. A NO2" reducing packed-bed bioreactor was employed to evaluate degradation of surfactant present in a typical space station greywater stream. The research was conducted to determine if a commercial surfactant could be used in the place of the current cleansing formulation and be degraded in biological water recycle system proposed for space travel. The commercial cleansing formulation used in the research was Pert Plus® for Kids (PPK), which contains sodium laureth sulfate (SLES) as the active surfactant. Experiments included a combination of microcosm experiments as well as a continuous-flow packed-bed bioreactor. The hydraulic retention time of the packed-bed bioreactor was varied through changes in flow rate to yield different steady-state values for NO2' reduction TOC, COD and SLES removal. Steady-state conditions allowed for the determination of degradation potential of both PPK and SLES. It was found that both constituents degraded well under NO2" reducing conditions. Stoichiometric relationships were used to determine if measured parameters could accurately predict the observed SLES degradation. Frora these relationships, it was found that other less common degradation pathways (biotic and/or abiotic) could have transformed SLES. Also, bacterial kinetics were determined for the currently used surfactant, Igepon T42 ™, and the commercial surfactant, SLES. From the rates determined it was found that Igepon T42™ exhibits faster degradation rates compared to the SLES. It was also found that the rates determined for SLES were concentration dependent. During this evaluation both PPK and SLES were effectively degraded under NO2" reducing conditions indicating their possible use in a WRS.Item Development of a chemo-denitritification process for wastewater(Texas Tech University, 1978-08) Bandy, John ThomasA physico-chemical method for removing nitrite nitrogen from wastewater has been developed. The process depends upon the reaction between ferrous sulfate and nitrite in acidified wastewater. The ferrous ions reduce nitrite nitrogen to gaseous nitrogen compounds such as nitric oxide which are evolved from solution. After the nitrogen has been removed, the pH of the wastestream is raised to the point at which the iron which was added precipitates from solution. The proposed chemo-denitritification system was demonstrated on a continuous flow basis at the bench scale level. Operating parameters for successful denitritification were found to include a three hour detention period, a reactor pH of less than 3.25, and an Fe :N0^ -N molar ratio of ten. Operation at other values of these parameters produced unacceptable concentrations of either nitrite or nitrate in the system effluent. Edgar Smith has developed a modified biological nitrification process which converts the ammonium nitrogen of wastewater to nitrite. The combination of the proposed chemo-denitritification process with Smith's nitritification process is potentially more economical than the conventional biological nitrification-denitrification process from which it was derived.Item Freshwater on the island of Maui : system interactions, supply, and demand(2011-05) Grubert, Emily; Webber, Michael E., 1971-; Passalacqua, Paola; King, CareyThis work is part of a broader, multi-year investigation of Maui Island’s freshwater resources. Maui Island faces multiple resource constraints, including water, land, energy, and capital, and these resource constraints could become relevant over the next forty years. Not only does Maui face potential changes to its water and other systems due to external factors beyond its control, like anthropogenic and other climate changes, but Maui also could make developmental choices that will impact how its resource systems interact. In particular, this work looks at Maui’s freshwater systems as they relate to energy, waste, and environmental systems. This report provides a foundation for future scenario analysis on the island that will aim to characterize potential synergies and hazards of choices like increased food production, local fuel production, and increased use of renewable energies.Item Membrane bioreactor treatment of household light greywater : measurement and effects of phosphorus limitation(2013-05) Van Epps, Amanda Jane; Katz, Lynn Ellen; Speitel, Gerald E.As water stresses increase across the U.S., interest in household water reuse is growing. Such reuse typically focuses on light greywater, that is all wastewater generated in the house excluding toilet waste and kitchen wastewater. As this practice becomes more widespread, higher level reuse is expected to require greater greywater treatment prior to reuse. Membrane bioreactors (MBRs) are an attractive technology for this application because they offer a robust combination of treatment processes and are already used in some households in countries such as Japan. This research sought to understand the role of phosphorus availability in determining the quality of effluent from MBR treatment of light greywater because phosphorus concentrations are expected to be low with phosphorus phased out of many consumer products. Less than 30 [mu]g/L of dissolved orthophosphate was present in synthetic greywater made from three common household products, and no measurable amount of dissolved orthophosphate was found in real greywater, but low concentrations of particulate phosphate were detected. These concentrations were well below levels believed necessary to achieve full BOD₅ removal in biological treatment. Nevertheless, MBR performance was not adversely affected until no supplemental phosphorus was provided. Measurement of extracellular enzyme activity showed an increase in the ratio of phosphatase activity to total glycosidase activity with declining phosphorus concentration, providing an early indication of nutrient stress before changes in effluent water quality were detected. Removal of three xenobiotic organic compounds (XOCs) in treatment of synthetic greywater was also evaluated under conditions of phosphorous limitation and balance. Abiotic removal mechanisms were not deemed to be important, but removal of methylparaben and sodium lauryl sulfate via biodegradation responded to nutrient limitation similarly to overall COD removal while removal of diethyl phthalate was affected to a greater extent. Measurement of plasmid DNA concentrations was evaluated as a potential indicator of the effect of nutrient limitation on plasmid-mediated biodegradation of XOCs. An overall reduction in the plasmid content was observed in all cases under conditions of phosphorus limitation; however, the extent of reduction was reactor dependent.Item Modification of waste water treatment using geotextiles(Texas Tech University, 2001-05) Kotha, Kishore KumarRemoval of suspended solids (SS) is one of the unit operation involved in the treatment of wastewater. Sedimentation process is widely used for the removal of SS from wastewater. But this method also has some disadvantages such as sludge handling and low removal efficiencies. In this investigation, nonwoven geotextiles with varying hydraulic and mechanical properties were used to treat municipal wastewater. Also, the performances of different geotextiles in treating wastewater with varying influent SS concentrations, were evaluated. Geotextile retains SS on its upstream face as wastewater is passed through it. Once the geotextile is clogged, it was backwashed with tap water for reuse. Our investigations revealed that the geotextiles were able to achieve very high removal efficiencies in the range of 70-90%, irrespective of the influent SS concentrations. But with a higher range of influent SS concentration (>200mg/L). the geotextiles exhibited very short clogging time, around 5 to 10 min., which required backwashing geotextiles every 10 min. This technique may prove to be suitable for treating low strength and low flow wastewaters having SS concentrations in the range of 100to200mg/L.Item Occurrence and fate of synthetic musk fragrances in effluent and non-effluent impacted environments: Detection in environmental matrices and implications for water policy(2011-08) Chase, Darcy; Anderson, Todd; Morse, Audra; Cobb, George P.Synthetic musk fragrances (SMFs) are considered micropollutants and can be found in various environmental matrices near wastewater discharge areas. These emerging contaminants are often detected in wastewater at low concentrations. They are continuously present and, therefore, constitute a constant exposure source. Objectives of this study were to investigate the environmental fate, transport, and transformation of SMFs. Occurrence of six polycyclic musk compounds (galaxolide, tonalide, cashmeran, celestolide, phantolide, traseolide) and two nitro musk compounds (musk xylene and musk ketone) were monitored in wastewater, various surface waters and their sediments, as well as groundwater, soil cores, and plants from a treated wastewater land application site. Specifically, samples were collected quarterly (1) from a wastewater reclamation plant to determine initial concentrations in wastewater effluent, (2) from a storage reservoir at a land application site to determine possible photolysis before land application, (3) from soil cores to determine the amount of sorption after land application, (4) from a lake system and its sediment to assess degradation, and (5) from non-effluent impacted local playa lakes and their sediments to assess potential sources of these compounds. Recently an innovative technique, stir-bar sorptive extraction (SBSE), was developed to extract organic contaminants from a variety of matrices. This method may lower detection limits and provide efficient analyses needed to detect SMFs in exclusive matrices such as those in this study (plants from a land application site and blood samples from ring-tailed lemurs (Lemur catta) in a remote location). Preliminary methods herein described were for using SBSE as a method to detect traceable concentrations in matrices not likely to accumulate high quantities of SMFs. Because SMFs are able to transport through different matrices along a remote pathway (i.e., from consumer product to wastewater to surface water or soil to groundwater then drinking water and even air and biota), SBSE is a method that can be used to validate the occurrence of SMFs and again affirm their ubiquitous nature. All samples were analyzed using gas chromatography coupled with selected ion mass spectrometry. Data indicated that occurrence of SMFs in effluent-impacted environments was detectable at ng/L and ng/g concentrations which decreased during transport throughout wastewater treatment. However, unexpected concentrations, ng/L and ng/g, were also detected in playa lakes not receiving treated effluent. Additionally, soil cores from land application sites had ng/g concentrations. Galaxolide and tonalide were consistently found in all environments, whereas various musks were found in non-effluent impacted environments. Galaxolide was also detected in exclusive matrices using SBSE techniques. Information on occurrence is critical to assessing exposure to these potentially endocrine disrupting compounds. Such information could provide a scientific framework for establishing the need for environmental regulations. Greywater use is a potential solution for addressing water shortages and sustainability. As water reuse practices increase, concerns about water quality should be addressed. The U.S. National Pollutant Discharge Elimination System (NPDES), under the Clean Water Act, limits the amount of discharged pollutants from wastewater treatment facilities in order to maintain water quality. Emerging organic pollutants not completely eliminated during treatment processes are not regulated by NPDES. These emerging contaminants may have an impact on the environment. Research on the occurrence, fate, and toxicity of emerging organic pollutants, specifically pharmaceuticals and personal care products (PPCPs), is needed to provide a scientific framework upon which appropriate environmental regulations could be established. Refining NPDES policy can address PPCPs found in wastewater, and lead to better monitoring and implementation of enhanced wastewater treatment. Integrative approaches that bridge scientific understanding with policy making can lead to healthier watersheds, ultimately improving the Clean Water Act goals.Item Recreational reuse potential of percolated municipal wastewater(Texas Tech University, 1975-12) Headstream, MarciaImpending water shortages through the southwestern United States have provided the impetus for the conception and implementation of various water reuse plans. A leader in this area is Lubbock, Texas. The city has been using its treated municipal effluent for irrigation purposes for over 35 years and is now in the process of making a second reuse of the wastewater. A series of recreational lakes being built in Yellowhouse Canyon, north and east of the city, will be fed with reclaimed percolated effluent. Recognizing the potential problems inherent in recreational reuse projects, the City of Lubbock enlisted the help of the Texas Tech University Water Resources Center in an advisory capacity. With the aid of an Office of. Water Research and Technology, Department of the Interior grant, a model of the Canyon Lakes Project consisting of nine common-wall concrete tanks was built on the University's farm land. The make-up water for the ponds was recovered percolated effluent of comparable quality to that which will be used in the actual project. The model system provided an excellent opportunity for ascertaining the suitability of reclaimed percolated municipal wastewater for recreational purposes, as well as an opportunity for more clearly defining the role of phosphorus in an aquatic environment. Researchers conducted studies relative to water quality, algal growth and control, suitability of the water for fish life and recreational contact, critical phosphorus levels, and the factors affecting the availability of phosphorus for algal growth. The results obtained from the study not only will be of value to the City of Lubbock in helping them to maintain an aesthetically pleasing system of lakes but also will be applicable to the successful operation of other warm water impoundments in the southern United States.Item Reinforcement learning in the control of a simulated life support system(Texas Tech University, 2003-12) Quasny, Todd MSince the 1970s, the National Aeronautics and Space Administration (NASA) has been conducting experiments to improve the duration and safety of manned space missions. For this purpose, an Advanced Life Support (ALS) system is being developed at NASA's Johnson Space Center (JSC). For research and testing purposes, an ALS system simulator, named BioSim, has been developed to simulate the interactions of the various subsystems of ALS. BioSim provides a testbed for researchers to develop and compare alternative control strategies for an ALS system. Reinforcement learning (RL) is a machine learning technique that finds effective control strategies. RL does this by interacting with the environment, and has been used successfully to control systems with noisy inputs and stochastic actions. RL methods are able to perform the real-time, reactive control that is vital in embedded control systems. This work demonstrates that reinforcement learning provides an excellent approach for finding an effective control policy for the water recovery subsystem of an ALS system. The control policy found by RL overcomes the inherent noisy inputs and stochastic actuation methods that exist in ALS systems. Using the policy found by RL, the mission duration is extended to nearly 450 days, at which point the mission ends for reasons other than the lack of consumable water. Since the mission does not end due to water concerns, it is concluded that an effective control policy for the water recovery system has been generated.Item Residential water reclamation in Texas : can it work?(2007-05) Dent, Kelly McCaughey; Butler, Kent S.Although Texas is a water reclamation leader in the country for quantity of water reclaimed, it falls behind both California and Florida in residential applications. The concept of residential reuse has some barriers to overcome prior to implementation on a broad scale in Texas. The two case studies, St. Petersburg, Florida, and the El Dorado Irrigation District of El Dorado County, California, describe extensive reuse programs in response not only to impending water shortages but also to effluent disposal limitation requirements. Major factors that limit residential reuse in Texas include the following: cost, expediency and negative public perception. Two other considerations exist when determining the feasibility of implementing residential reuse: income level and irrigation needs. Most of the successful reuse programs examined were for higher income areas. Also, irrigation expectations and needs of the residences play a major factor in the success of the program. In arid environments planted with drought-tolerant plants, landscape irrigation becomes less of a priority. Further limitations that specifically affect Texas’ expanding its water reclamation programs include the legal issues of existing water rights and direct versus indirect reuse.Item Survival and growth of fish in water reclaimed from cattle feedlots(Texas Tech University, 2000-05) Cox, Thomas J.Today there is a growing realization that we must reuse and conserve our natural resources to minimize pollution and environmental degradation. This concern has brought about an interest in integrated systems, which reuse water and produce marketable products in the process. With this in mind, several departments from Texas Tech University have collaborated to construct an integrated system to treat the effluent from a 1000-head cattle feedlot at the Texas Tech Animal Science Farm. This integrated system includes an integrated facultative pond (IFP), which produces and captures methane for energy production, a constructed wetland for filtration and plant production, and a aquaculture system. The goal of this research was: (1) to assess the feasibility of growing and maintaining stocks of bait fish, sport fish, and tropical fish within an integrated system designed to remediate effluents from confined animal feeding operations; and (2) to determine environmental tolerance ranges for each of the fish species tested. This research was conducted at the Texas Tech University 4th Street greenhouse location in Lubbock, Texas. Anaerobically digested cattle manure was diluted with freshwater to prepare seven concentrations, which were loaded into six pilot-scale wetland systems. Effluents exiting each wetland then passed through a four-tank raceway system constructed after each wetland. Fish were evaluated in reclaimed water containing a target COD concentrations of 0, 20, 100, 300, 500, 650, and 900 mg/L. The survival and growth of eight species: koi (Cyprinus carpio). bluegill (Lepomis macrochirus), channel catfish (Ictalurus punctatus), fathead minnow (Pimephales promelas), redfin shiner (Notropis umbratilis). tilapia (Tilapia aurea), sailfin molly Poecilia latipinna), and platies (Xiphophorus maculatas) were evaluated in 2-week trials (10 fish/ trial). It was concluded that it is feasible for all of the species tested to be utilized in an integrated waste management system. Koi, platy, bluegill, molly, fathead minnow, redfin shiner were tolerant of COD concentrations up to 366 mg/L. Channel catfish and tilapia were the most tolerant of the species tested and had survival rates as high as 73% in COD concentrations of 810 mg/L. Optimal ranges for each of the species were based on the highest survival, growth rates and condition. Platty, fathead minnow, and tilapia preformed optimally at COD concentrations between 79-145 mg/L. The optimal range for molly, bluegill, and channel catfish was at COD concentrations of approximately 366 mg/L. Koi and redfin shiner survival and growth rates were optimal at COD concentrations between 145-366 mg/L.Item Use of alternate water sources in construction operations(Texas Tech University, 2003-05) Rajagopalan, SrinathDue to population growth, construction and periodic drought, water has become a precious commodity, especially for areas in the state that receive very little rainfall. One way to reduce the demand for drinking water is to substitute non-drinking quality water in construction applications. Primary benefits of this approach include: reducing the demand for the drinking quality water; reducing construction costs, and decreasing construction delays if water rationing is imposed on drinking water supplies. The objective of this project was to identify usable alternative water sources for construction applications. To achieve this objective, alternative water supplies were identified and characterized for quality, availability, and price. Additionally, each proposed water source was evaluated to determine if there are any adverse health concerns or environmental impact from its reuse. Potential impact from the use of low quality water on constractability, material behavior and performance were also evaluated. The primary product of this research was a decision matrix that allows TXDOT engineers to evaluate an alternate water source (e.g., reclaimed water and brine water) for construction applications like dust control and compaction in various soil types. In addition, readily accessible computer database that TxDOT engineers can use to determine allowable applications of each identified water source as well as information concerning location and contact information for each source was developed.