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PubMed2003

Low nanogram per liter determination of halogenated nonylphenols, nonylphenol carboxylates, and their non-halogenated precursors in water and sludge by liquid chromatography electrospray tandem mass spectrometry.

A new LC-MS-MS method for quantitative analysis of nonylphenol (NP), nonylphenol carboxylates (NPECs), and their halogenated derivatives: brominated and chlorinated nonylphenols (BrNP, ClNP), brominated and chlorinated nonylphenol carboxylates (BrNPE(1)C and ClNPE(1)C) and ethoxycarboxylates (BrNPE(2)C and ClNPE(2)C) in water and sludge has been developed. Electrospray negative ionization MS-MS was applied for the identification of above mentioned compounds. Upon collision-induced dissociation, their deprotonated molecules gave different fragments formed by the cleavage of the alkyl moiety and/or (ethoxy)carboxylic moiety. For halogenated compounds a highly diagnostic characteristic pattern of isotopic doublet signals was obtained and fragmentation yielded, in addition to above mentioned ions, [Br](-) and [Cl](-), respectively. Quantitative analysis was done in the multiple reaction monitoring (MRM) mode, using two specific combinations of a precursor-product ion transitions for each compound. Additionally, for halogenated compounds two specific channels for each transition reaction, corresponding to two isotopes, were monitored and the ratio of their abundances used as an identification criterion. The method has been validated in terms of sensitivity, selectivity, accuracy, and precision and was applied to the analysis of water and sludge samples from drinking water treatment plant (DWTP) of Barcelona (Catalonia, NE Spain). Halogenated NP and NPECs were detected in prechlorinated water in concentrations up to 315 ng/L, BrNPE(2)C being the most abundant compound. In the DWTP effluent non-halogenated compounds were detected at trace levels (85, 12 and 10 ng/L for NP, NPE(1)C, and NPE(2)C, respectively), whereas concentration of halogenated derivatives never exceeded 10 ng/L. Nonylphenol, brominated and chlorinated NPs were found in flocculation sludge in concentrations of 150, 105, and 145 microg/kg, respectively. Acidic polar metabolites were found in lower concentrations up to 20 microg/kg.

Carboxylic Acids↗

PubMed2006

[Continuous ethanol fermentation coupled with recycling of yeast flocs].

A continuous ethanol fermentation system composed of three-stage tanks in series coupled with two sedimentation tanks was established. A self-flocculating yeast strain developed by protoplast fusion from Saccharomyces cerevisiae and Schizosaccharomyces pombe was applied. Two-stage enzymatic hydrolysate of corn powder containing 220g/L of reducing sugar, supplemented with 1.5g/L (NH4)2HPO4 and 2.5g/L KH2PO4, was used as the ethanol fermentation substrate and fed into the first fermentor at the dilution rate of 0.057h(-1). The yeast flocs separated by sedimentation were recycled into the first fermentor as two different models: activation-recycle and direct recycle. The quasi-steady states were obtained for both operation models after the fermentation systems experienced short periods of transitions. Activation process helped enhance the performance of ethanol fermentation at the high dilution rates. The broth containing more than 101g/L ethanol, 3.2g/L residual reducing sugar and 7.7g/L residual total sugar was produced. The ethanol productivity was calculated to be 5.77g/(L x h), which increased by more than 70% compared with that achieved in the same tank in series system without recycling of yeast cells.

Biomass↗

PubMedDate not supplied

Separation characteristics of liquid nematode cultures and the design of recovery operations.

Production of nematode-based pesticides involves the recovery of a viable nematode life stage known as the infective juvenile (IJ) from fermentation broth. Waste components to be separated from the IJs include non-IJ life stages, dead nematodes, nematode debris, spent media, and the nematode's associated bacteria. This paper reports separation characteristics of liquid cultures and suspensions of the nematodes Phasmarhabditis hermaphrodita, Steinernema feltiae, and Heterorhabditis megidis measured at small scale. Separation characteristics were determined for dead-end filtration, gravity settling and flotation. Results were used to identify large-scale recovery procedures. Separation of culture liquid by dead-end filtration of the crude fermentation broth was not possible due to rapid blinding of filters. However, nematode-water suspensions prepared by gravity settling could be concentrated using this separation method. Settling tests indicated that IJs could be efficiently separated from culture liquid by centrifugation but not by gravity settling. Examination of the effects of nematode concentration indicated an optimum concentration for gravity settling that may entail modest dilution of the fermentation broth. Flocculation of insoluble spent media in suspensions of P. hermaphrodita prevented its separation from nematodes by gravity settling. However, attachment of air bubbles to spent media allowed removal by flotation. Finally, adjustment of continuous phase density using sucrose allowed separation of non-IJ life stages, dead nematodes, and discarded cuticles from the IJs by flotation. The efficiency of this separation decreased with increasing nematode-solute contact time.

Animals↗

PubMed2002

Removal of pharmaceuticals during drinking water treatment.

The elimination of selected pharmaceuticals (bezafibrate, clofibric acid, carbamazepine, diclofenac) during drinking water treatment processes was investigated at lab and pilot scale and in real waterworks. No significant removal of pharmaceuticals was observed in batch experiments with sand under natural aerobic and anoxic conditions, thus indicating low sorption properties and high persistence with nonadapted microorganisms. These results were underscored by the presence of carbamazepine in bank-filtrated water with anaerobic conditions in a waterworks area. Flocculation using iron(III) chloride in lab-scale experiments (Jar test) and investigations in waterworks exhibited no significant elimination of the selected target pharmaceuticals. However, ozonation was in some cases very effective in eliminating these polar compounds. In lab-scale experiments, 0.5 mg/L ozone was shown to reduce the concentrations of diclofenac and carbamazepine by more than 90%, while bezafibrate was eliminated by 50% with a 1.5 mg/L ozone dose. Clofibric acid was stable even at 3 mg/L ozone. Under waterworks conditions, similar removal efficiencies were observed. In addition to ozonation, filtration with granular activated carbon (GAC) was very effective in removing pharmaceuticals. Except for clofibric acid, GAC in pilot-scale experiments and waterworks provided a major elimination of the pharmaceuticals under investigation.

Biodegradation, Environmental↗

PubMed2003

Occurrence and removal of estrogenic short-chain ethoxy nonylphenolic compounds and their halogenated derivatives during drinking water production.

The elimination of nonylphenol (NP), nonylphenol mono- and diethoxylates (NP1EO and NP2EO), nonylphenol carboxylates (NP1EC and NP2EC) and their brominated and chlorinated derivatives during drinking water treatment process in Sant Joan Despf waterworks in Barcelona was investigated utilizing a recently developed, highly sensitive LC-MS-MS method. The concentration of these potentially estrogenic compounds in raw water entering waterworks (taken from the Llobregat River, NE Spain) ranged from 8.3 to 22 microg/L, with NP2EC being the most abundant compound. Prechlorination reduced the concentration of short-chain ethoxy NPECs and NPEOs by about 25-35% and of NP by almost 90%. However, this reduction of concentrations was partially due to their transformation to halogenated derivatives. After prechlorination, halogenated nonylphenolic compounds represented approximately 13% of the total metabolite pool, of which 97% were in the form of brominated acidic metabolites. The efficiency of further treatment steps to eliminate nonylphenolic compounds (calculated for the sum of all short-chain ethoxy metabolites including halogenated derivatives) was as follows: settling and flocculation followed by rapid sand filtration (7%), ozonation (87%), GAC filtration (73%), and final disinfection with chlorine (43%), resulting in overall elimination ranging from 96 to 99% (mean 98% for four sampling dates). A few of the nonylphenolic compounds (NP, NP1EC, and NP2EC) were also identified in drinking water; however, the residues detected were generally below 100 ng/L, with one exception for NP2EC in November 2001 when a concentration of 215 ng/L was detected.

Estrogens, Non-Steroidal↗

PubMed2005

Solid-phase microextraction measurement of parent and alkyl polycyclic aromatic hydrocarbons in milliliter sediment pore water samples and determination of K(DOC) values.

The U.S. Environmental Protection Agency (EPA) narcosis model for benthic organisms in polycyclic aromatic hydrocarbon (PAH) contaminated sediments requires the measurement of 18 parent PAHs and 16 groups of alkyl PAHs ("34" PAHs) in pore water with desired detection limits as low as nanograms per liter. Solid-phase microextraction (SPME) with gas chromatographic/mass spectrometric (GC/ MS) analysis can achieve such detection limits in small water samples, which greatly reduces the quantity of sediment pore water that has to be collected, shipped, stored, and prepared for analysis. Four sediments that ranged from urban background levels (50 mg/kg total "34" PAHs) to highly contaminated (10 000 mg/kg total PAHs) were used to develop SPME methodology for the "34" PAH determinations with only 1.5 mL of pore water per analysis. Pore water was obtained by centrifuging the wet sediment, and alum flocculation was used to remove colloids. Quantitative calibration was simplified by adding 15 two- to six-ring perdeuterated PAHs as internal standards to the water calibration standards and the pore water samples. Response factors for SPME followed by GC/MS were measured for 22 alkyl PAHs compared to their parent PAHs and used to calibrate for the 18 groups of alkyl PAHs. Dissolved organic carbon (DOC) ranging from 4 to 27 mg/L had no measurable effect on the freely dissolved concentrations of two- and three-ring PAHs. In contrast, 5-80% of the total dissolved four- to six-ring PAHs were associated with the DOC rather than being freely dissolved, corresponding to DOC/water partitioning coefficients (K(DOC)) with log K(DOC) values ranging from 4.1 (for fluoranthene) to 5.6 (for benzo[ghi]perylene). However, DOC-associated versus freely dissolved PAHs had no significant effect on the total "34" PAH concentrations or the sum of the "toxic units" (calculated bythe EPA protocol), since virtually all (86-99%) of the dissolved PAH concentrations and toxic units were contributed by two- and three-ring PAHs.

Benzopyrenes↗

PubMed2006

The impact of zeta potential on the physical properties of ferric--NOM flocs.

The physical properties of natural organic matter (NOM) flocs, such as size, growth rate, and strength, were investigated using a laser diffraction particle sizing device. Conditions were set such that varying carbon coagulant ratio and zeta potential could both be investigated. Results demonstrated a link between zeta potential and coagulation and flocculation performance, with the production of strong flocs and low residual concentrations when the zeta potential was minimized. The overall strength of the connection points within the floc were determined by a combination of steric interactions, polymer bridging, van der Waals forces, and electrostatic forces. Hence, both dose ratio and zeta potential are important in understanding floc properties. Floc growth was dominated by dose ratio, whereas the response to elevated shear was strongly related to zeta potential. The steady-state floc size was a combination of both factors. This allowed the continued development of a qualitative model in order to engineer optimal floc properties when coagulating NOM.

Ferric Compounds↗

PubMed2003

Enhanced biological phosphate removal by granular sludge in a sequencing batch reactor.

A laboratory-scale sequencing batch reactor was started-up with flocculated biomass and operated primarily for enhanced biological phosphate removal. Ten weeks after the start-up, gradual formation of granular sludge was observed. The compact biomass structure allowed halving the settling time, the initial reactor volume, and doubling the influent COD concentration. Continued operation confirmed the possibility of maintaining a stable granular biomass with a sludge volume index less than 40 ml g-1, while securing a removal efficiency of 95% for carbon, 99.6% for phosphate, and 71% for nitrogen. Microscopic observations revealed a morphological diversity.

Bacteria, Aerobic↗

PubMed2004

Floc characterisation by analysis of laser beam attenuation.

The continuous growth in the demand of good quality water for different purposes makes the control of environmental pollution a matter for public and official concern. The monitoring of particles for quality control of water or wastewater treatment is becoming important and the need for the development of control devices is increasing. The purpose of this work was to develop a photosedimentation method for floc characterization combining gravitational settling with photoelectric measurements. Settling particles cross a light beam that illuminates a detection system. The attenuation of the beam is related to the projected area of the particles and so the particle size distribution can be determined. When a floc crosses the beam, the amount of light reaching the detector is reduced. Voltage/time signals are analyzed in order to produce the physical characteristics of flocs such as size and density. Different light sources and detection systems were tested in calibration tests and afterwards flocculated suspensions were used for experimental analysis. Floc characteristics could then be related to the experimental conditions of floc formation (mixing conditions and polymer concentration). With the experience acquired, a prototype was designed and implemented, being capable of operating in laboratory or field conditions.

Environmental Monitoring↗

PubMed2002

Treatment of effluents of poultry slaughterhouse with aluminum salts and natural polyelectrolytes.

A mixture of aluminum salts and natural polyelectrolytes, extracted from the cactus Opuntia ficus indica, has been used for cleaning of wastewater from poultry slaughterhouse. The aggregation and settling properties of colloids and complex organics such as oil, grease, fats, proteins, and suspended solids, was increased if compared with conventional methods of wastewater treatment using only aluminum or iron sulfate. A mixture of aluminum salt in a concentration range of 300 to 600 mg l(-1) and natural polyelectrolytes of 0.6 to 0.8 mg l(-1) was used for flocculation and coagulation. The combination of coagulant and natural polyelectrolytes was able to remove chemical oxygen demand (86%), oil and grease (93%), turbidity (89%), and suspended solids (93%). Methanization activity was also investigated for the effluents in natura.

Abattoirs↗

PubMed2002

Flocculation/aggregation of cohesive sediments in the urban continuum: implications for stormwater management.

The urban continuum, as it applies to sediments and associated contaminants, represents the area over/through which sediments are conveyed from a depositional or eroded surface to a treatment system and/or receiving water body. This study has focused on the changing physical characteristics of the sediment, with an emphasis on flocculation/aggregation, as it progresses through the urban continuum. The sediments of the urban continuum are found to change from an unflocculated state on the street, to a flocculated state in the surface runoff to a very large floc form in the sewer system. The high organic content in the sewers contributes to the large floc size. The structure of the flocs and the flow regime of the receiving water will dictate the fate of the sediment following a combined sewer overflow. Probability distributions fitted to the distributions of each sediment type (compartment) confirmed significant differences in the sediment population sizes. Bulk and individual particle settling velocity experiments also revealed substantial differences between compartments. Sewer flocs were found to be of low density, with high porosity, water and organic content and with settling velocities which increase with floc size.

Cities↗

PubMed2006

Two-factor design for coagulant/flocculant doses effect for solid-liquid separation of dairy manure.

Screened dairy manure, with a total solids content equal to 34.7 g TS l(-1), was subjected to a coagulation-flocculation treatment using FeCl, as coagulant and a medium cationic polyacrylamide (MCP1). The effect of changing doses of the additives (FeCl3 and MCP1) on the properties of supernatant fractions was studied by means of design of response surface using "Statgraphics Plus 3.0" program. The results showed that the values of concentrations found in supernatants obtained after settling of the flocs for two of the dependent variables studied, filtrate chemical oxygen demand (CODf) and total organic carbon (TOC), were significantly influenced by both the FeCl3 and MCP1 doses at an error lower than 5%. The values of concentrations of the remaining variables studied (TS, VS, CODt, CODvfa) were significantly influenced only by the MCP1 dose at an error lower than 5%. The predictive model obtained the best satisfactory parameters for TOC supernatant's concentration (R2=0.980, F-ratio = 438.89 (p-value < 0.05)) and the worse for VS (R2 = 0.783, F-ratio = 33.43 (p-value < 0.05)).

Acrylic Resins↗

PubMed2003

Removal of Encephalitozoon intestinalis, calicivirus, and coliphages by conventional drinking water treatment.

The removal of the Microsporidia, Encephalitozoon intestinalis, feline calicivirus and coliphages MS-2, PRD-1, and Fr were evaluated during conventional drinking water treatment in a pilot plant. The treatment consisted of coagulation, sedimentation, and mixed media filtration. Fr coliphage was removed the most (3.21 log), followed by feline calicivirus (3.05 log), E. coli (2.67 log), E. intestinalis (2.47 log), MS-2 (2.51 log). and PRD-1 (1.85 log). With the exception of PRD-1 the greatest removal of the viruses occurred during the flocculation step of the water treatment process.

Animals↗

PubMed1980

A quantitative enzyme immunoassay for IgM rheumatoid factor using human immunoglobulin G as substrate.

A quantitative "sandwich" enzyme-immunoassay for IgM rheumatoid factor (RF) using human immunoglobulin G as substrate covalently bound to small plastic discs is described. The findings indicate that it is a simple, sensitive, reproducible, and specific method for measuring RF activity. Test results are reported in IU/ml on the basis of the World Health Organization reference RF serum, permitting standardized reporting of this determination between laboratories using this method. Interassay and interlaboratory variability of results are less than 7%. The enzyme-linked immunosorbent assay (ELISA) results correlated well with those found by latex and bentonite flocculation titrations. A number of ELISA RF-positive specimens that were latex-negative and/or Waaler-Rose-negative were confirmed positive by inhibition of the assay with soluble aggregated human IgG, but not with nonaggregated human IgG. Comparison was made between ELISA RF results when using goat or human IgG as substrate. Human IgG was usually more reactive with RFs than was goat IgG.

Agglutination Tests↗

PubMed1979

Arctic trichinosis: two Alaskan outbreaks from walrus meat.

The arctic form of Trichinella spiralis that infects terrestrial and marine mammals is of importance in public health because persons living in arctic regions still depend on wild animals for economic subsistence. In 1975, an extended common-source epidemic of trichinosis attributed to consumption of walrus meat involved 29 persons in Barrow, Alaska. Of those persons eating this meat, 64% became ill, and the rate of infection of persons eating meat prepared with little or no cooking was four times as great as that of persons eating cooked meat. One year later a second outbreak occurred when a family ate partially cooked meat from an infected walrus. Clinical illness differed little from the disease acquired in temperature climates; however, only 70% had a positive bentonite flocculation titer, whereas 96% had eosinophilia. These epidemics of trichinosis are the first reported in Alaska to be associated with the consumption of walrus meat.

Alaska↗

PubMed1990

Construction of a novel artificial-ribozyme-releasing plasmid.

A novel 'active-ribozyme-releasing system' was constructed, taking advantage of the consensus sequence of a new class of ribozyme. An active ribozyme sequence, targeted for the SFL1 gene (a yeast suppressor gene for flocculation) was fused just downstream of the T7 promoter. The 3' terminus of the first ribozyme was designed to be trimmed by the second ribozyme connected to the downstream of the first active ribozyme. In vitro experiments revealed that the active ribozyme targeted to SFL1 was successfully released by the action of the second ribozyme, subsequently cleaving the SFL1 mRNA at the predetermined site. Since the first active ribozyme with a defined 3'-terminus can be produced even when a circular DNA is used as a template, this kind of construct has a potential to release an 'active ribozyme' tailored to destroy a target gene (RNA) in vivo. Moreover, the second ribozyme in this construct can be utilized as a universal pseudo-terminator for generation of any RNA transcripts inserted in place of the cassette portion of the first ribozyme.

Base Sequence↗

PubMed2004

Reduction of bacterial indicators and bacteriophages infecting faecal bacteria in primary and secondary wastewater treatments.

AIMS: To compare the suitability of various bacterial and viral indicators to assess the removal of faecal micro-organisms by primary and secondary wastewater treatment processes. METHODS AND RESULTS: The numbers of several bacterial indicators [faecal coliforms (FC), enterococci (ENT) and sulphite-reducing clostridia (SRC)] and bacteriophages (somatic coliphages, F-specific RNA phages and bacteriophages infecting Bacteroides fragilis strain RYC2056) were determined in incoming raw sewage and effluents from various primary and secondary wastewater treatment processes in several geographical areas. Reductions in the numbers of indicators were calculated as log10 reductions. Processes based on removal and mild disinfection, showed no significant differences in the elimination of any of the indicators tested or between geographical areas. In contrast, treatment processes that include strong microbial inactivation, such as lime-aided flocculation and lagooning, showed significant differences between the log10 reductions of the various micro-organisms studied, FC showing the highest reduction and spores of SRC and phages infecting B. fragilis the lowest. CONCLUSIONS: The microbial elimination performance of treatment processes based principally on removal and mild disinfection can be evaluated with a single indicator. In contrast, processes with additional disinfecting capabilities require more than one indicator for accurate evaluation of the treatment; bacteriophages are good candidates for use as second indicators. SIGNIFICANCE AND IMPACT OF THE STUDY: Bacteriophages provide additional information for the evaluation of microbial elimination in some treatment plants. The easy, fast and cheap methods available for phage determination are feasible both in industrialized and developing countries.

Bacteria↗

PubMed1972

Crystalline cholera toxin and toxoid.

The exo-enterotoxin of Vibrio cholerae has been obtained in crystalline form. A solution of the crystalline protein was equal in potency to the parent pure toxin in both choleragenicity and skin reactivity. Crystals of the natural toxoid, choleragenoid, resemble those of the toxin in appearance. A solution of crystalline choleragenoid was equivalent to the parent preparation in the flocculation test.

Animals↗