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Description
Biofuel from microbial biomass is a viable alternative to current energy production practices that could mitigate greenhouse gas levels and reduce dependency on fossil fuels. Sustainable production of microbial biomass requires efficient utilization of nutrients like phosphorus (P). P is a limited resource which is vital for global food security.

Biofuel from microbial biomass is a viable alternative to current energy production practices that could mitigate greenhouse gas levels and reduce dependency on fossil fuels. Sustainable production of microbial biomass requires efficient utilization of nutrients like phosphorus (P). P is a limited resource which is vital for global food security. This paper seeks to understand the fate of P through biofuel production and proposes a proof-of-concept process to recover P from microbial biomass. The photosynthetic cyanobacterium Synechocystis sp. PCC 6803 is found to contain 1.4% P by dry weight. After the crude lipids are extracted for biofuel processing, 92% of the intercellular P is found within the residual biomass. Most intercellular P is associated with nucleic acids which remain within the cell after lipids are extracted. Phospholipids comprise a small percentage of cellular P. A wet chemical advanced oxidation process of adding 30% hydrogen peroxide followed by 10 min of microwave heating converts 92% of the total cellular P from organic-P and polyphosphate into orthophosphate. P was then isolated and concentrated from the complex digested matrix by use of resins. An anion exchange resin impregnated with iron nanoparticles demonstrates high affinity for P by sorbing 98% of the influent P through 20 bed volumes, but only was able to release 23% of it when regenerated. A strong base anion exchange resin sorbed 87% of the influent P through 20 bed volumes then released 50% of it upon regeneration. The overall P recovery process was able to recover 48% of the starting intercellular P into a pure and concentrated nutrient solution available for reuse. Further optimization of elution could improve P recovery, but this provides a proof-of-concept for converting residual biomass after lipid extraction to a beneficial P source.
ContributorsGifford, James McKay (Author) / Westerhoff, Paul (Thesis advisor) / Rittmann, Bruce (Committee member) / Vannela, Ravindhar (Committee member) / Arizona State University (Publisher)
Created2012
Description
Filtration for microfluidic sample-collection devices is desirable for sample selection, concentration, preprocessing, and downstream manipulation, but microfabricating the required sub-micrometer filtration structure is an elaborate process. This thesis presents a simple method to fabricate polydimethylsiloxane (PDMS) devices with an integrated membrane filter that will sample, lyse, and extract the DNA

Filtration for microfluidic sample-collection devices is desirable for sample selection, concentration, preprocessing, and downstream manipulation, but microfabricating the required sub-micrometer filtration structure is an elaborate process. This thesis presents a simple method to fabricate polydimethylsiloxane (PDMS) devices with an integrated membrane filter that will sample, lyse, and extract the DNA from microorganisms in aqueous environments. An off-the-shelf membrane filter disc was embedded in a PDMS layer and sequentially bound with other PDMS channel layers. No leakage was observed during filtration. This device was validated by concentrating a large amount of cyanobacterium Synechocystis in simulated sample water with consistent performance across devices. After accumulating sufficient biomass on the filter, a sequential electrochemical lysing process was performed by applying 5VDC across the filter. This device was further evaluated by delivering several samples of differing concentrations of cyanobacterium Synechocystis then quantifying the DNA using real-time PCR. Lastly, an environmental sample was run through the device and the amount of photosynthetic microorganisms present in the water was determined. The major breakthroughs in this design are low energy demand, cheap materials, simple design, straightforward fabrication, and robust performance, together enabling wide-utility of similar chip-based devices for field-deployable operations in environmental micro-biotechnology.
ContributorsLecluse, Aurelie (Author) / Meldrum, Deirdre (Thesis advisor) / Chao, Joseph (Thesis advisor) / Westerhoff, Paul (Committee member) / Arizona State University (Publisher)
Created2011
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Description
Local municipalities in the Phoenix Metropolitan Area have voiced an interest in purchasing alternate source water with lower DBP precursors. Along the primary source is a hydroelectric dam in which water will be diverted from. This project is an assessment of optimizing the potential blends of source water to a

Local municipalities in the Phoenix Metropolitan Area have voiced an interest in purchasing alternate source water with lower DBP precursors. Along the primary source is a hydroelectric dam in which water will be diverted from. This project is an assessment of optimizing the potential blends of source water to a water treatment plant in an effort to enable them to more readily meet DBP regulations. To perform this analysis existing water treatment models were used in conjunction with historic water quality sampling data to predict chemical usage necessary to meet DBP regulations. A retrospective analysis was performed for the summer months of 2007 regarding potential for the WTP to reduce cost through optimizing the source water by an average of 30% over the four-month period, accumulating to overall treatment savings of $154 per MG ($82 per AF).
ContributorsRice, Jacelyn (Author) / Westerhoff, Paul (Thesis advisor) / Fox, Peter (Committee member) / Hristovski, Kiril (Committee member) / Arizona State University (Publisher)
Created2011
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Description
As engineered nanomaterials (NMs) become used in industry and commerce their loading to sewage will increase. However, the fate of widely used NMs in wastewater treatment plants (WWTPs) remains poorly understood. In this research, sequencing batch reactors (SBRs) were operated with hydraulic (HRT) and sludge (SRT) retention times representative of

As engineered nanomaterials (NMs) become used in industry and commerce their loading to sewage will increase. However, the fate of widely used NMs in wastewater treatment plants (WWTPs) remains poorly understood. In this research, sequencing batch reactors (SBRs) were operated with hydraulic (HRT) and sludge (SRT) retention times representative of full-scale biological WWTPs for several weeks. NM loadings at the higher range of expected environmental concentrations were selected. To achieve the pseudo-equilibrium state concentration of NMs in biomass, SBR experiments needed to operate for more than three times the SRT value, approximately 18 days. Under the conditions tested, NMs had negligible effects on ability of the wastewater bacteria to biodegrade organic material, as measured by chemical oxygen demand (COD). NM mass balance closure was achieved by measuring NMs in liquid effluent and waste biosolids. All NMs were well removed at the typical biomass concentration (1~2 gSS/L). However, carboxy-terminated polymer coated silver nanoparticles (fn-Ag) were removed less effectively (88% removal) than hydroxylated fullerenes (fullerols; >90% removal), nano TiO2 (>95% removal) or aqueous fullerenes (nC60; >95% removal). Although most NMs did not settle out of the feed solution without bacteria present, approximately 65% of the titanium dioxide was removed even in the absence of biomass simply due to self-aggregation and settling. Experiments conducted over 4 months with daily loadings of nC60 showed that nC60 removal from solution depends on the biomass concentration. Under conditions representative of most suspended growth biological WWTPs (e.g., activated sludge), most of the NMs will accumulate in biosolids rather than in liquid effluent discharged to surface waters. Significant fractions of fn-Ag were associated with colloidal material which suggests that efficient particle separation processes (sedimentation or filtration) could further improve removal of NM from effluent. As most NMs appear to accumulate in biosolids, future research should examine the fate of NMs during disposal of WWTP biosolids, which may occur through composting or anaerobic digestion and/or land application, incineration, or landfill disposal.
ContributorsWang, Yifei (Author) / Westerhoff, Paul (Thesis advisor) / Krajmalnik-Brown, Rosa (Committee member) / Rittmann, Bruce (Committee member) / Hristovski, Kiril (Committee member) / Arizona State University (Publisher)
Created2012
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Description
The presence of compounds such as pharmaceuticals and personal care products (PPCPs) in the environment is a cause for concern as they exhibit secondary effects on non-target organisms and are also indicative of incomplete removal by wastewater treatment plants (WWTPs) during water reclamation. Analytical methods and predictive models can hel

The presence of compounds such as pharmaceuticals and personal care products (PPCPs) in the environment is a cause for concern as they exhibit secondary effects on non-target organisms and are also indicative of incomplete removal by wastewater treatment plants (WWTPs) during water reclamation. Analytical methods and predictive models can help inform on the rates at which these contaminants enter the environment via biosolids use or wastewater effluent release to estimate the risk of adverse effects. The goals of this research project were to integrate the results obtained from the two different methods of risk assessment, (a) in silico modeling and (b) experimental analysis. Using a previously published empirical model, influent and effluent concentration ranges were predicted for 10 sterols and validated with peer-reviewed literature. The in silico risk assessment analysis performed for sterols and hormones in biosolids concluded that hormones possess high leaching potentials and that particularly 17-α-ethinyl estradiol (EE2) can pose significant threat to fathead minnows (P. promelas) via leaching from terrestrial depositions of biosolids. Six mega-composite biosolids samples representative of 94 WWTPs were analyzed for a suite of 120 PPCPs using the extended U.S. EPA Method 1694 protocol. Results indicated the presence of 26 previously unmonitored PPCPs in the samples with estimated annual release rates of 5-15 tons yr-1 via land application of biosolids. A mesocosm sampling analysis that was included in the study concluded that four compounds amitriptyline, paroxetine, propranolol and sertraline warrant further monitoring due to their high release rates from land applied biosolids and their calculated extended half-lives in soils. There is a growing interest in the scientific community towards the development of new analytical protocols for analyzing solid matrices such as biosolids for the presence of PPCPs and other established and emerging contaminants of concern. The two studies presented here are timely and an important addition to the increasing base of scientific articles regarding environmental release of PPCPs and exposure risks associated with biosolids land application. This research study emphasizes the need for coupling experimental results with predictive analytical modeling output in order to more fully assess the risks posed by compounds detected in biosolids.
ContributorsPrakash Chari, Bipin (Author) / Halden, Rolf U. (Thesis advisor) / Westerhoff, Paul (Committee member) / Fox, Peter (Committee member) / Arizona State University (Publisher)
Created2012
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Description
Nanotechnology is becoming increasingly present in our environment. Engineered nanoparticles (ENPs), defined as objects that measure less than 100 nanometers in at least one dimension, are being integrated into commercial products because of their small size, increased surface area, and quantum effects. These special properties have made ENPs antimicrobial agents

Nanotechnology is becoming increasingly present in our environment. Engineered nanoparticles (ENPs), defined as objects that measure less than 100 nanometers in at least one dimension, are being integrated into commercial products because of their small size, increased surface area, and quantum effects. These special properties have made ENPs antimicrobial agents in clothing and plastics, among other applications in industries such as pharmaceuticals, renewable energy, and prosthetics. This thesis incorporates investigations into both application of nanoparticles into polymers as well as implications of nanoparticle release into the environment. First, the integration of ENPs into polymer fibers via electrospinning was explored. Electrospinning uses an external electric field applied to a polymer solution to produce continuous fibers with large surface area and small volume, a quality which makes the fibers ideal for water and air purification purposes. Indium oxide and titanium dioxide nanoparticles were embedded in polyvinylpyrrolidone and polystyrene. Viscosity, critical voltage, and diameter of electrospun fibers were analyzed in order to determine the effects of nanoparticle integration into the polymers. Critical voltage and viscosity of solution increased at 5 wt% ENP concentration. Fiber morphology was not found to change significantly as a direct effect of ENP addition, but as an effect of increased viscosity and surface tension. These results indicate the possibility for seamless integration of ENPs into electrospun polymers. Implications of ENP release were investigated using phase distribution functional assays of nanoscale silver and silver sulfide, as well as photolysis experiments of nanoscale titanium dioxide to quantify hydroxyl radical production. Functional assays are a means of screening the relevant importance of multiple processes in the environmental fate and transport of ENPs. Four functional assays – water-soil, water-octanol, water-wastewater sludge and water-surfactant – were used to compare concentrations of silver sulfide ENPs (Ag2S-NP) and silver ENPs (AgNP) capped by four different coatings. The functional assays resulted in reproducible experiments which clearly showed variations between nanoparticle phase distributions; the findings may be a product of the effects of the different coatings of the ENPs used. In addition to phase distribution experiments, the production of hydroxyl radical (HO•) by nanoscale titanium dioxide (TiO2) under simulated solar irradiation was investigated. Hydroxyl radical are a short-lived, highly reactive species produced by solar radiation in aquatic environments that affect ecosystem function and degrades pollutants. HO• is produced by photolysis of TiO2 and nitrate (NO3-); these two species were used in photolysis experiments to compare the relative loads of hydroxyl radical which nanoscale TiO2 may add upon release to natural waters. Para-chlorobenzoic acid (pCBA) was used as a probe. Measured rates of pCBA oxidation in the presence of various concentrations of TiO2 nanoparticles and NO3- were utilized to calculate pseudo first order rate constants. Results indicate that, on a mass concentration basis in water, TiO2 produces hydroxyl radical steady state concentrations at 1.3 times more than the equivalent amount of NO3-; however, TiO2 concentrations are generally less than one order of magnitude lower than concentrations of NO3-. This has implications for natural waterways as the amount of nanoscale TiO2 released from consumer products into natural waterways increases in proportion to its use.
ContributorsHoogesteijn von Reitzenstein, Natalia (Author) / Westerhoff, Paul (Thesis advisor) / Herckes, Pierre (Committee member) / Hristovski, Kiril (Committee member) / Arizona State University (Publisher)
Created2015
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Description
Arsenic (As) is a naturally occurring element that poses a health risk when continually consumed at levels exceeding the Environmental Protection Agencies (EPA) maximum contaminant level (MCL) of 10 ppb. With the Arizona Department of Water Resources considering reliance on other sources of water other than just solely surface water,

Arsenic (As) is a naturally occurring element that poses a health risk when continually consumed at levels exceeding the Environmental Protection Agencies (EPA) maximum contaminant level (MCL) of 10 ppb. With the Arizona Department of Water Resources considering reliance on other sources of water other than just solely surface water, groundwater proves a reliable, supplemental source. The Salt River Project (SRP) wants to effectively treat their noncompliance groundwater sources to meet EPA compliance. Rapid small-scale column tests (RSSCTs) of two SRP controlled groundwater wells along the Eastern Canal and Consolidated Canal were designed to assist SRP in selection and future design of full-scale packed bed adsorbent media. Main concerns for column choice is effectiveness, design space at groundwater wells, and simplicity. Two adsorbent media types were tested for effective treatment of As to below the MCL: a synthetic iron oxide, Bayoxide E33, and a strong base anion exchange resin, SBG-1. Both media have high affinity toward As and prove effective at treating As from these groundwater sources. Bayoxide E33 RSSCT performance indicated that As treatment lasted to near 60,000 bed volumes (BV) in both water sources and still showed As adsorption extending past this operation ranging from several months to a year. SBG-1 RSSCT performance indicated As, treatment lasted to 500 BV, with the added benefit of being regenerated. At 5%, 13%, and 25% brine regeneration concentrations, regeneration showed that 5% brine is effective, yet would complicate overall design and footprint. Bayoxide E33 was selected as the best adsorbent media for SRP use in full-scale columns at groundwater wells due to its simplistic design and high efficiency.
ContributorsLesan, Dylan (Author) / Westerhoff, Paul (Thesis advisor) / Hristovski, Kiril (Committee member) / Fraser, Matthew (Committee member) / Arizona State University (Publisher)
Created2015
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Description
With the application of reverse osmosis (RO) membranes in the wastewater treatment and seawater desalination, the limitation of flux and fouling problems of RO have gained more attention from researchers. Because of the tunable structure and physicochemical properties of nanomaterials, it is a suitable material that can be used to

With the application of reverse osmosis (RO) membranes in the wastewater treatment and seawater desalination, the limitation of flux and fouling problems of RO have gained more attention from researchers. Because of the tunable structure and physicochemical properties of nanomaterials, it is a suitable material that can be used to incorporate with RO to change the membrane performances. Silver is biocidal, which has been used in a variety of consumer products. Recent studies showed that fabricating silver nanoparticles (AgNPs) on membrane surfaces can mitigate the biofouling problem on the membrane. Studies have shown that Ag released from the membrane in the form of either Ag ions or AgNP will accelerate the antimicrobial activity of the membrane. However, the silver release from the membrane will lower the silver loading on the membrane, which will eventually shorten the antimicrobial activity lifetime of the membrane. Therefore, the silver leaching amount is a crucial parameter that needs to be determined for every type of Ag composite membrane.

This study is attempting to compare four different silver leaching test methods, to study the silver leaching potential of the silver impregnated membranes, conducting the advantages and disadvantages of the leaching methods. An In-situ reduction Ag loaded RO membrane was examined in this study. A custom waterjet test was established to create a high-velocity water flow to test the silver leaching from the nanocomposite membrane in a relative extreme environment. The batch leaching test was examined as the most common leaching test method for the silver composite membrane. The cross-flow filtration and dead-end test were also examined to compare the silver leaching amounts.

The silver coated membrane used in this experiment has an initial silver loading of 2.0± 0.51 ug/cm2. The mass balance was conducted for all of the leaching tests. For the batch test, water jet test, and dead-end filtration, the mass balances are all within 100±25%, which is acceptable in this experiment because of the variance of the initial silver loading on the membranes. A bad silver mass balance was observed at cross-flow filtration. Both of AgNP and Ag ions leached in the solution was examined in this experiment. The concentration of total silver leaching into solutions from the four leaching tests are all below the Secondary Drinking Water Standard for silver which is 100 ppb. The cross-flow test is the most aggressive leaching method, which has more than 80% of silver leached from the membrane after 50 hours of the test. The water jet (54 ± 6.9% of silver remaining) can cause higher silver leaching than batch test (85 ± 1.2% of silver remaining) in one-hour, and it can also cause both AgNP and Ag ions leaching from the membrane, which is closer to the leaching condition in the cross-flow test.
ContributorsHan, Bingru (Author) / Westerhoff, Paul (Thesis advisor) / Perreault, Francois (Committee member) / Sinha, Shahnawaz (Committee member) / Arizona State University (Publisher)
Created2017
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Description
Iodide (I-) in surface and groundwaters is a potential precursor for the formation of iodinated disinfection by-products (I-DBPs) during drinking water treatment. The aim of this thesis is to provide a perspective on the sources and occurrence of I- in United States (US) source waters based on ~9200 surface water

Iodide (I-) in surface and groundwaters is a potential precursor for the formation of iodinated disinfection by-products (I-DBPs) during drinking water treatment. The aim of this thesis is to provide a perspective on the sources and occurrence of I- in United States (US) source waters based on ~9200 surface water (SW) and groundwater (GW) sampling locations. The median I- concentrations observed was 16 μg/l and 14 μg/l, respectively in SW and GW. However, these samples were rarely collected at water treatment plant (WTP) intakes, where such iodide occurrence data is needed to understand impacts on DBPs. Most samples were collected in association with geochemical studies. We conclude that I- occurrence appears to be influenced by geological features, including halite rock/river basin formations, saline aquifers and organic rich shale/oil formations. Halide ratios (Cl-/I-, Br-/I- and Cl-/Br-) were analyzed to determine the I- origin in source waters. SW and GW had median Cl-/I- ratios of ~3600 μg/μg and median Br-/I- ratios of ~15 μg/μg. For states with I- concentration >50 μg/l (e.g., Montana and North Dakota), a single source (i.e., organic rich formations) can be identified. However, for states like California and Texas that have wide-ranging I- concentration of below detection limit to >250 μg/l, I- occurrence can be attributed to a mixture of marine and organic signatures. The lack of information of organic iodine, inorganic I- and IO3- in source waters limits our ability to predict I-DBPs formed during drinking water treatment, and new occurrence studies are needed to fill these data gaps. This is first of its kind study to understand the I- occurrence through historical data, however we also identify the shortcomings of existing databases used to carry out this study.
ContributorsSharma, Naushita (Author) / Westerhoff, Paul (Thesis advisor) / Lackner, Klaus (Committee member) / Herckes, Pierre (Committee member) / Arizona State University (Publisher)
Created2018
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Description
The production and applications of engineered nanomaterials (ENM) has increased rapidly in the last decade, with release of ENM to the environment through the sewer system and municipal wastewater treatment plants (WWTPs) being of concern. Currently, the literature on ENM release from WWTPs and removal of ENM by WWTPs is

The production and applications of engineered nanomaterials (ENM) has increased rapidly in the last decade, with release of ENM to the environment through the sewer system and municipal wastewater treatment plants (WWTPs) being of concern. Currently, the literature on ENM release from WWTPs and removal of ENM by WWTPs is insufficient and disorganized. There is little quantitative data on the removal of multi-walled carbon nanotubes (MWCNTs), graphene oxide (GO), or few-layer graphene (FLG), from wastewater onto biomass. The removal of pristine and oxidized MWCNTs (O-MWCNTs), graphene oxide (GO), few-layer graphene (FLG) and Tween™ 20-coated Ag ENM by the interaction with biomass were determined by programmable thermal analysis (PTA) and UV-Vis spectrophotometry. The removal of pristine and O-MWCNTs was 96% from the water phase via aggregation and 30-min settling in presence or absence of biomass with an initial MWCNT concentration of 25 mg/L. The removal of 25 mg/L GO was 65% with biomass concentration at or above 1,000 mg TSS/L. The removal of 1 mg/L FLG was 16% with 50 mg TSS/L. The removal of Tween™ 20 Ag ENM with concentration from 0.97 mg/L to 2.6 mg/L was from 11% to 92% with biomass concentration of 500 mg TSS/L to 3,000 mg TSS/L, respectively.

A database of ENM removal by biomass was established by analyzing data from published papers, and non-linear solid-liquid distribution functions were built into the database. A conventional activated sludge (CAS) model was built based on a membrane bioreactor (MBR) model from a previous paper. An iterative numeric approach was adapted to the CAS model to calculate the result of non-linear adsorption of ENM by biomass in the CAS process. Kinetic studies of the CAS model showed the model performance changed mostly in the first 10 days after changing influent chemical oxygen demand (COD) concentration, and reached a steady state after 11 days. Over 60% of ENMs which have distribution coefficients in the database reached higher than 50% removal by the CAS model under general operational conditions. This result suggests that traditional WWTP which include the CAS process can remove many known types of ENMs in certain degree.
ContributorsYu, Zhicheng (Author) / Westerhoff, Paul (Thesis advisor) / Rittmann, Bruce (Committee member) / Herckes, Pierre (Committee member) / Arizona State University (Publisher)
Created2015