Molecular Biomarkers and Influential Factors of Denitrification in a Full-Scale Biological Nitrogen Removal Plant.

Three denitrifying bacteria, spp., spp., -like spp.

Comparison of DNA Extraction Efficiency and Reproducibility of Different Aeration Diffuser Biofilms Using Bead-Beating Protocol.

An existing bead-beating DNA extraction protocol was employed to compare the DNA extraction recovery and fragment quality of 6 different aeration diffuser biofilms. Escherichia coli, Gordonia amarae, and mixed liquor were used as controls. The fraction of total DNAbiofilm decreased monotonically with increasing number of beat beatings (BB) when the amount of DNA present was sufficient (>4 μgDNA/cm2), excluding the ceramic disk.

Impact of fouling on the decline of aeration efficiency under different operational conditions at WRRFs.

Biofilm formation influences the most energy-demanding process in the waste water treatment cycle. Biofilm growth on the surface of wastewater aeration diffusers in water resource recovery facilities (WRRFs) can increase the energy requirements up to 50% in less than 2 years. The impact of biofilms in aeration diffusers was quantified and assessed for first time using molecular tools (i.

Fate and Toxicity of Zinc Oxide Nanomaterial in Municipal Wastewaters.

  The production of zinc nanomaterial has increased significantly over the past several years and, as a result, nanoparticles have navigated their way into wastewater streams. The transportation and toxicity of zinc nanomaterial within the wastewater treatment processes is not well known. In this study, the zinc nanomaterial and its fate were characterized in an activated sludge treatment process.

Modelling the link amongst fine-pore diffuser fouling, oxygen transfer efficiency, and aeration energy intensity.

This research systematically studied the behavior of aeration diffuser efficiency over time, and its relation to the energy usage per diffuser. Twelve diffusers were selected for a one year fouling study. Comprehensive aeration efficiency projections were carried out in two WRRFs with different influent rates, and the influence of operating conditions on aeration diffusers' performance was demonstrated.

A survey of biofilms on wastewater aeration diffusers suggests bacterial community composition and function vary by substrate type and time.

Aeration diffusers in wastewater treatment plants generate air bubbles that promote mixing, distribution of dissolved oxygen, and microbial processing of dissolved and suspended matter in bulk solution. Biofouling of diffusers represents a significant problem to wastewater treatment plants because biofilms decrease oxygen transfer efficiency and increase backpressure on the blower. To better understand biofouling, we conducted a pilot study to survey the bacterial community composition and function of biofilms on different diffuser substrates and compare them to those in the bulk solution.

Raffinose, a plant galactoside, inhibits Pseudomonas aeruginosa biofilm formation via binding to LecA and decreasing cellular cyclic diguanylate levels.

Biofilm formation on biotic or abiotic surfaces has unwanted consequences in medical, clinical, and industrial settings. Treatments with antibiotics or biocides are often ineffective in eradicating biofilms. Promising alternatives to conventional agents are biofilm-inhibiting compounds regulating biofilm development without toxicity to growth.

Linking biofilm growth to fouling and aeration performance of fine-pore diffuser in activated sludge.

Aeration is commonly identified as the largest contributor to process energy needs in the treatment of wastewater and therefore garners significant focus in reducing energy use. Fine-pore diffusers are the most common aeration system in municipal wastewater treatment. These diffusers are subject to fouling and scaling, resulting in loss in transfer efficiency as biofilms form and change material properties producing larger bubbles, hindering mass transfer and contributing to increased plant energy costs.

Identification and quantification of Thiothrix eikelboomii using qPCR for early detection of bulking incidents in a full-scale water reclamation plant.

This study found that the ratio of Thiothrix eikelboomii to total bacterial concentrations (TH/TB) (%) was a better indicator of bulking incidents affecting effluent quality compared to absolute T. eikelboomii abundance alone. This was determined using a genus-specific Thiothrix quantitative PCR primer and probe set, which was developed in this study to monitor specific Thiothrix populations over a 1-year period.

Interaction of operational and physicochemical factors leading to Gordonia amarae-like foaming in an incompletely nitrifying activated sludge plant.

The overgrowth of Gordonia amarae-like bacteria in the mixed liquor of an incompletely nitrifying water reclamation plant was inversely correlated with temperature (r = -0.78; P < 0.005) and positively correlated with the solids retention time (SRT) obtained a week prior to sampling (r = 0.

Evaluation of nanocopper removal and toxicity in municipal wastewaters.

Bench scale studies were performed to evaluate removal and toxicity of copper nanoparticles (CuNPs) and copper ions in activated sludge biomass. The data indicated that, under the test conditions, copper nanoparticles were removed more effectively (∼95%) than copper ions (30-70%) from the wastewater. Mechanisms of CuNP removal were further investigated by equilibrating CuNP and copper ion in activated sludge filtrate (0.

Influence of physicochemical and operational parameters on Nitrobacter and Nitrospira communities in an aerobic activated sludge bioreactor.

To understand how to optimize performance of a partially nitrifying plant, the dynamics of Nitrospira and Nitrobacter abundance were studied over a 1 year period using quantitative polymerase chain reaction (qPCR) and their relative contributions to nitrite oxidation assessed including the affects of temperature and dissolved oxygen (DO). Correlation coefficients linking shifts in the community composition of nitrite-oxidizing bacteria (NOB) to operational or environmental variables indicated Nitrospira was significantly and negatively correlated to nitrite concentrations (r = -0.45, P < 0.

Classification and regression tree (CART) analysis for indicator bacterial concentration prediction for a Californian coastal area.

The study used existing indicator bacterial data and a number of physicochemical parameters that can be measured instantaneously to determine if a decision tree approach, especially classification and regression tree, could be used to predict bacterial concentrations in timely manner for beach closure management. Each indicator bacteria showed different tree structures and each had its own significant variables; Dissolved oxygen played an important role for both total coliform and fecal coliform and turbidity was the most important factor to predict concentrations of enterococci for decision tree approaches. Root mean squared error stayed between 5 and 6.

Identification and application of physical and chemical parameters to predict indicator bacterial concentration in a small Californian creek.

This study of Aliso Creek in California aimed to identify physical and chemical parameters that could be measured instantly to be used in a model to serve as surrogates for indicator bacterial concentrations during dry season flow. In this study, a new data smoothing technique and ranking/categorizing analysis was used to reduce variation to allow better delineation of the relationships between adopted variables and concentrations of indicator bacteria. The ranking/categorizing approach clarified overall trends between physico-chemical data and the indicators and suggested sources of the bacteria.

Development of a quantitative PCR method to differentiate between viable and nonviable bacteria in environmental water samples.

Ethidium monoazide bromide (EMA) treatment of pure culture and environmental waters at low concentrations (1.0-7.5 microg/ml) indicated effective enumeration of viable and viable but nonculturable Escherichia coli in pure cultures, creek waters, and secondary activated sludge effluent samples by quantitative polymerase chain reaction (qPCR) amplification of the uidA and fliC gene targets at turbidity values < 10 NTU.

Relationship among growth parameters for Clostridium butyricum, hydA gene expression, and biohydrogen production in a sucrose-supplemented batch reactor.

This study was undertaken to identify the relationship between the performance of dark H2 fermentation and expression of the key functional gene (i.e., hydrogenase gene) involved in the bioH2 production process.

Improving PCR and qPCR detection of hydrogenase A (hydA) associated with Clostridia in pure cultures and environmental sludges using bovine serum albumin.

Detection of hydA genes of Clostridia spp. using degenerative and species specific primers for C. butyricum were optimized by the addition of bovine serum albumin (BSA) to polymerase chain reaction (PCR) and quantitative PCR (qPCR) reactions.

Microbial source tracking in a small southern California urban watershed indicates wild animals and growth as the source of fecal bacteria.

Three independent microbial source tracking (MST) methods were applied to a small urban subwatershed in Orange County, California. Fifty-seven water samples collected over summer 2002 were analyzed for human adenovirus and enterovirus. Enterococci and E.

Estimating the economic burden from illnesses associated with recreational coastal water pollution--a case study in Orange County, California.

A cost-of-illness framework was applied to health and income data to quantify the health burden from illnesses associated with exposure to polluted recreational marine waters. Using data on illness severity due to exposure to polluted coastal water and estimates of mean annual salaries and medical costs (adjusted to 2001 values) for residents of Orange County, California, we estimated that the economic burden per gastrointestinal illness (GI) amounts to 36.58 dollars, the burden per acute respiratory disease is 76.

Health effects associated with recreational coastal water use: urban versus rural California.

We compared rates of reported health symptoms among surfers in urban North Orange County (NOC) and rural Santa Cruz County (SCC), California, during 2 winters (1998 and 1999) to determine whether symptoms were associated with exposure to urban runoff. NOC participants reported almost twice as many symptoms as SCC participants during the 1998 winter. In both study years, risk increased across symptom categories by an average of 10% for each 2.

Occurrence of genes associated with enterotoxigenic and enterohemorrhagic Escherichia coli in agricultural waste lagoons.

The prevalence among all Escherichia coli bacteria of the LTIIa toxin gene and STII toxin gene, both associated with enterotoxigenic E. coli, and of three genes (stxI, stxII, and eaeA) associated with enterohemorrhagic E. coli was determined in farm waste disposal systems seasonally for 1 year.

Magnetic bead hybridization to detect enterotoxigenic Escherichia coli strains associated with cattle in environmental water sources.

A magnetic capture hybridization - polymerase chain reaction (MCH-PCR) method was used to increase the detection sensitivity of the enterotoxin gene LTIIa, used as a biomarker for waste in environmental samples. The samples were collected from cow lagoons of different farms and from environmental waters. Total DNA was extracted from colonies grown on mTEC medium or directly from environmental samples.

PCR-restriction fragment length polymorphism method for detection of Cyclospora cayetanensis in environmental waters without microscopic confirmation.

We developed an alternative nested-PCR-restriction fragment length polymorphism (RFLP) protocol for the detection of Cyclospora cayetanensis in environmental samples that obviates the need for microscopic examination. The RFLP method, with the restriction enzyme AluI, differentiates the amplified target sequence from C. cayetanensis from those that may cross-react.

Cyclospora cayetanensis: a review of an emerging parasitic coccidian.

Cyclospora cayetanensis is a sporulating parasitic protozoan that infects the upper small intestinal tract. It has been identified as both a food and waterborne pathogen endemic in many developing countries. It is an important agent of Traveller's Diarrohea in developed countries and was responsible for numerous foodborne outbreaks in the United States and Canada in the late 1990s.

Association of urban runoff with coastal water quality in Orange County, California.

The associations between storm events, urban runoff, and coastal water quality have not been well investigated. A temporal and spatial analysis of 2 years of data was conducted to determine associations between urban river discharge and indicator bacteria levels for Southern California beaches and evaluate the contribution of anomalous precipitation to the association. Data show beaches next to rivers had the highest bacterial levels in both wet and dry seasons.