Process Water Samples Research Articles

Incidence and sources of Listeria monocytogenes in a traditional hot‐smoked rainbow trout processing plant in Turkey†

SummaryIn recent years, microbial fish safety is getting a close attention from regulatory agencies and consumers. Therefore, fish farm raising rainbow trout and affiliated slaughterhouse and smoking plants were evaluated for the occurrence of Listeria monocytogenes. Samples including raw fish, swabbings of equipment or other surfaces, as well as processing water, salt, fish feed and fish samples taken after various stages of processing were collected from thirty different locations in the plant. For the detection of L. monocytogenes, both conventional and Listeria Rapid Test (LRT) were used. L. monocytogenes was detected in thirty out of sixty samples (50%) by LRT, while it was detected in thirty‐four out of sixty samples (57%) by conventional method. No L. monocytogenes was detected from raw fish, smoked fish (before handling) and processing water, but it was detected in all environmental samples including swabbings of equipment or other surfaces and smoked fish samples after filleting.

Characterization of arsenic (V) and arsenic (III) in water samples using ammonium molybdate and estimation by graphite furnace atomic absorption spectroscopy

Arsenic (V) is known to form heteropolyacid with ammonium molybdate in acidic aqueous solutions, which can be quantitatively extracted into certain organic solvents. In the present work, 12-molybdoarsenic acid extracted in butan-1-ol is used for quantification of As (V). Total arsenic is estimated by converting arsenic (III) to arsenic (V) by digesting samples with concentrated nitric acid before extraction. Concentration of As (III) in the sample solutions could be calculated by the difference in total arsenic and arsenic (V). The characterization of arsenic was carried out by GFAAS using Pd as modifier. Optimization of the experimental conditions and instrumental parameters was investigated in detail. Recoveries of (90–110%) were obtained in the spiked samples. The detection limit was 0.2 μg l −1. The proposed method was successfully applied for the determination of trace amount of arsenic (III) and arsenic (V) in process water samples.

Diversity of bacteria contaminating paper machines

Formation of microbial biofilms and slimes is a general and serious problem in the operation of paper machines. Studies of microbial populations in paper machine-derived biofilms have been conducted using standard microbiological procedures; however, the bacterial genera present in this type of samples as well as their diversity are quite poorly known. Here, the bacterial diversity of 38 process water and 22 biofilm samples from four different Finnish paper machines were analyzed by length heterogeneity analysis of PCR-amplified 16S ribosomal DNA (LH-PCR). In addition, sequencing of the amplified 16S rRNA gene from 69 clones was conducted for characterization of the bacterial genera present in biofilm and slime samples. The LH-PCR profiles of both the free-living (process waters) and immobilized (biofilms) bacteria were diverse at all stages of the papermaking process. Out of the 69 sequenced clones, 44 belonged to alpha-Proteobacteria, most of which were close to the nitrogen-fixing root nodule genera Sinorhizobium, Rhizobium and Azorhizobium. Other clones were assigned to beta- and gamma-Proteobacteria and the phylum Bacteroidetes. In addition, eight of the clones were assigned to a yet uncultivated phylum, TM7. Finally, epifluorescence microscopy revealed that Gram-negative bacteria were predominant in both the biofilm (65%) and process water (54%) samples and a small coccoid cell morphology was most common in all samples. Together, our results show that the analysis of microbial samples from paper machines using modern molecular biology techniques adds valuable information and should, therefore, be useful as a more specific and sensitive microbiological method for the paper industry. This information could further be applied, e.g., in the development of more specific and environmental friendly antimicrobial agents for paper mills.

Dissolution of fibre material in alkaline pre-treatment and refining of spruce CTMP

Abstract The chemistry of chemithermomechanical pulping (CTMP) was assessed by chemical pre-treatment of spruce chips, followed by laboratory-scale refining. Pre-treatments with alkali, sulfite, alkaline sulfite and alkaline peroxide liquors were carried out at 40°C, 60°C and 80°C. The sodium hydroxide dosages were 1% and 2% and the sodium sulfite and hydrogen peroxide dosages were 2%, 4% and 6% on a dry wood basis. Process water samples were taken before and after refining. Alkali consumption in the pre-treatments and the amount and composition of released wood components were determined. A major part of the alkali was consumed in the alkaline and alkaline sulfite pre-treatments. In the alkaline peroxide pre-treatments, however, alkali consumption was considerably lower. Acetic acid was the main wood component released to the process waters in alkaline pre-treatments. Pectins, determined as galacturonic acid and rhamnose by acid methanolysis, were also released to some extent, as well as easily soluble polysaccharides. After fibre separation in refining, more hemicelluloses and pectins were released. There was a significant difference between the degree of demethylation for pectins and the degree of deacetylation for galactoglucomannans after the pre-treatments. The diffusion of chemicals into the secondary wall layers seemed to be slower than the liquor penetration into the porous middle lamella through the pit pores. Up to 10% of the pectins were dissolved in the process waters as a result of depolymerisation and extensive demethylation. The residual amount of pectins in the fibres, however, was determined to be as low as 65–70% of the initial pectin content.

Selective and Simultaneous Determination of Phosphate and Silicate Ions in Leaching Process Waters for Ceramics Glaze Raw Materials of Narutal Origin by Ion-Exclusion Chromatography Coupled with UV-detection after Postcolumn Derivatization

The selective and simultaneous ion-exclusion chromatography (IEC) with UV-detection on a weakly acidic cation-exchange resin column in the H+ -form (TSKgel Super IC-A/C) was developed and applied for the simultaneous determination of phosphate and silicate ions as the water quality parameters required for optimizing the water-leaching process for ceramics glaze raw materials of natural origin including feldspar, woods-ash, and straw-ash. Phosphate and silicate ions in these water-leaching process water samples were separated selectively from the coexisting anions such as sulfate, chloride, nitrate and carbonate ions, based on the ion-exclusion separation mechanism. They were detected selectively and simultaneously by a postcolumn derivatization with molybdenum-yellow using the UV-detector. Under the optimized separation and detection conditions (eluent, 0-1 mM sulfuric acid; reactant, 10 mM sodium molybdate-25 mM sulfuric acid; detector, UV at 370 nm; temperature, 45 degrees C), the linearity of calibration was in the range 0.1 - 10 ppm for both phosphate and silicate ions, and the detection limits at S/N = 3 were 2.58 ppb for silicate ions and 4.75 ppb for phosphate ions. The effectiveness of this method was demonstrated in practical applications to the water-leaching process for some ceramics glaze raw materials.

Determination of hexafluoroarsenate in industrial process waters by anion-exchange chromatography-inductively coupled plasma-mass spectrometry (AEC-ICP-MS)

We describe the first specific method for the determination of the hexafluoroarsenate ion in waters, involving anion-exchange chromatography coupled to inductively coupled plasma-mass spectrometry. The detection limit was estimated to be 6 ng L−1 (as arsenic), and complete separation from all other known inorganic arsenic species and methylated arsenic biocides is accomplished. Hexafluoroarsenate was detected in process water samples from an industrial fluoride-rich environment, where it constituted the vast majority (78–100%) of the total arsenic present. It was not removed from these process waters by iron hydroxide co-precipitation. The analytical and environmental implications of our findings are discussed.

Development of homologous viral internal controls for use in RT-PCR assays of waterborne enteric viruses

Enteric viruses often contaminate water sources causing frequent outbreaks of gastroenteritis. Reverse transcription-polymerase chain reaction (RT-PCR) assays are commonly used for detection of human enteric viruses in environmental and drinking water samples. RT-PCR provides a means to rapidly detect low levels of these viruses, but it is sensitive to inhibitors that are present in water samples. Inhibitors of RT-PCR are concentrated along with viruses during sample processing. While procedures have been developed to remove inhibitors, none of them completely remove all inhibitors from all types of water matrices. This problem requires that adequate controls be used to distinguish true from potentially false-negative results. To address this problem, we have developed homologous viral internal controls for hepatitis A virus (HAV), poliovirus, Norwalk virus and rotavirus. These internal controls can be used in RT-PCR assays for the detection of the above viruses by competitive amplification, thereby allowing the detection of false negatives in processed water samples. The internal controls developed in this study were successfully tested with virus-seeded environmental water sample concentrates.

On-line process monitoring of water-soluble ions in pulp and paper machine waters by capillary electrophoresis

In this study, capillary electrophoresis (CE) was used for separation of inorganic and organic ions from waters of paper and paperboard machines at mills. The instrument was constructed for on-line measurements by building a batch-type sample feeding unit. Chloride, thiosulphate, sulphate, oxalate, sulphite, hydrogen sulphide, formate, carbonate, phosphate and acetate in the process water samples were separated using an ion-specific separation system in CE with dicarboxylic acid buffer (pH 8.2), with pyridinium-2,3-dicarboxylic acid modified with commercial NICE-Pak OFMOH solution (pH 12.0) or with a cetyltrimethylammonium bromide solution modified with chromate (pH 10.6). In addition, Analis CEofix Anions 8 electrolyte solution was tested in on-line studies at mills. It allowed 5 min separation time for the anions. Aluminium was determined at pH 3.6 in 10 min by using a laboratory-made imidazole buffer modified with 18-crown 6-ether. The developed CE systems were used to monitor the concentrations of sulphur species in dithionite degradation, to estimate corrosion degree in the water tanks, to monitor formaldehyde as the biocide chemical in wire washing and, in general, to observe process disturbances resulting from chemical feedings and their sites. The CE combination was on-line coupled to eight different process machines for continuous monitoring of concentrations for periods between two weeks and one month at paper and pulp mills in Finland.

Gas chromatography/mass spectrometry demonstration of steryl glycosides in eucalypt wood, Kraft pulp and process liquids.

The occurrence of steryl glycosides (SG) and acyl steryl glycosides (ASG) in eucalypt (Eucalyptus globulus) wood has been investigated. These compounds were analyzed as their trimethylsilyl ethers by gas chromatography/mass spectrometry (GC/MS) using a 15 m length high-temperature capillary column with a thin film, and identified on basis of their mass spectra and relative retention times comparing with those of authentic standards. Significant amounts of SG were identified in eucalypt wood whilst only traces of ASG could be detected. Eucalypt SG and ASG occur in the pyranoside form, which is readily distinguishable from the furanoside configuration by the mass spectra of their trimethylsilyl derivatives. The sterol part of the SG and ASG consisted of sitosterol, being sitosteryl 3beta-D-glucopyranoside and sitosteryl (6'-O-palmitoyl)-3beta-D-glucopyranoside, the major SG and ASG found in E. globulus wood. The presence of SG and ASG was also investigated after kraft cooking by analyzing unbleached pulp and process water samples. The GC/MS results also revealed the presence of sitosteryl 3beta-D-glucopyranoside in these samples. By contrast, no ASG could be detected. Therefore, we have shown that SG survive the kraft cooking and can be found at least partly intact after pulping, being a possible cause for pitch deposits together with free and esterified sterols.

Determination of low thiourea concentrations in industrial process water and natural samples using reversed-phase high-performance liquid chromatography

A rapid LC method was developed to determine thiourea in natural samples and freshly prepared as well as used tin-baths from the galvanic industry, with LC on a C 18-bonded silica column and with doubly distilled water as eluent. The retention time of thiourea is 1.35 min±5%. UV detection is at 236 nm. Small sample volumes of 10–50 μl allow detection down to 2 μg/l thiourea without any interference by heavy metals or organic compounds and in the case of marine samples by mineral salts. The presented technique should be highly useful for industrial purposes.

Resin acid markers for total resin acid content of in-mill process lines of a TMP/CTMP pulp mill

Resin acids are a class of lipophilic extractives present in process waters of pulp and paper mills using softwoods as a furnish. These compounds cause pitch problems and adversely affect paper properties. As pulp and paper mills move toward water systems closure the concentration of these extractives are expected to increase. Therefore, it will become more important to monitor and control extractives content in the process lines of pulp and paper mills. Resin acids are traditionally analyzed by gas chromatography (GC). This method of analysis requires extracting the analytes from a sample matrix, separating by solid phase extraction and derivatizing the resin acids to increase their volatility. Although this process is tedious and expensive and cannot be used as an on-line monitoring system, it does provide quantification of the individual resin acids with a low detection limit. Finding marker compounds for the total resin acid content of an in-mill process water sample may aid in the development of a fast and reliable monitoring system. A preliminary GC analysis of 25 in-mill process water samples established abietic acid as the best single marker for total resin acid content. A correlation of 0.964 was found between the abietic acid concentration and the total resin acid content of these samples. This result led to the analysis of 167 samples from a previous audit of resin acid content of in-mill process water samples. Abietic acid was the single best marker for these samples as well with a correlation of 0.928. An improved correlation of 0.957 was obtained if a combination of isopimaric and abietic acid contents was used as the marker for total resin acid content. Dehydroabietic acid, which has been shown to be a good marker for total resin acid content of mill effluent samples, was a poor marker for in-mill samples. A correlation of only 0.664 was obtained between DHA and total resin acid content of the samples analyzed.

Simultaneous Determination of Small Cations and Anions by Capillary Electrophoresis

A capillary electrophoresis system for the simultaneous determination of small cations and anions has been developed. Cations and anions in a sample are separated in one single electrophoretic run using one capillary and just one detector. The sample is injected into the first end of the separation capillary and subsequently into the second end. When the high voltage is applied, the cations and the anions in the two injected sample portions start to migrate against each other toward the center of the capillary. The detection window is placed approximately in the middle of the capillary. A suitable electrolyte consists of 6 mM 4-aminopyridine, 2.7 mM H2CrO4, and 30 μM cetyltrimethylammonium bromide at pH 8. The composition of the background electrolyte provides excellent separation of 22 small inorganic and organic anions and 1A and 2A class cations within 5 min. The overall repeatability of the migration times is less than 0.3%, and the repeatability of the peak area ranges from 1.7 to 5.5% (n = 9) based on manual hydrodynamic injections with a duration of 40 s. The technique has been applied for the analysis of tap water, rainwater, and process water samples. The total time for an analysis of both cations and anions in a water sample is less than 3 min. Milk and mud samples were also analyzed after off-line dialysis pretreatment.

Determination of nitrophenols by capillary zone electrophoresis in a hydrodynamically closed separation compartment

The use of β-cyclodextrin (β-CD) and polyvinylpyrrolidone (PVP) as complexing agents to capillary zone electrophoretic (CZE) separations of a group of ten nitrophenols was investigated. The analytes were baseline resolved in one CZE run when PVP was present in the carrier electrolyte at a 2.5% (w/v) concentration. β-CD was less effective as it did not baseline resolve a complete group of the studied nitrophenols within an applicable concentration range (0–10 mmol/l). The separations were carried out in a 300-μm I.D. capillary tube made of fluorinated ethylene–propylene copolymer to enhance the load capacity of the separation system. Under these working conditions, a 100-nl sample injection volume resulted in 20–80 ppb concentration limits of detection for nitrophenols, using a photometric absorbance detector operating at a wavelength of 254 nm. The separation efficiencies for the analytes spanned from 1.6–2·105 theoretical plates per meter. Their migration times were reproducible not only in a within day but also in a day-to-day time frame (1% or less for a period of several weeks). This was achieved for a hydrodynamically closed separation compartment while minimizing fluctuations in the concentration of CO2 in the carrier electrolyte. Reproducibility in the determination of nitrophenols was in the range of 1–5% for 1–6 ppm concentrations. Rain, drinking and process water samples served as matrices to assess the practical applicability of the elaborated CZE procedure. This procedure can be combined with isotachophoretic sample pretreatment to make its use possible in situations when nitrophenols are present in the samples at low ppb concentrations.

Determination of mercury species in natural waters at picogram level with on-line RP C18 preconcentration and HPLC-UV-PCO-CVAAS

A new technique has been developed for the determination of methyl-, ethyl-, methoxyethyl-, ethoxyethyl-, phenyl- and inorganic mercury in natural water samples. The mercury compounds have been complexed for the preconcentration on RP C18 columns by sodium pyrrolidinedithiocarbamate (SPDC), sodium diethyldithiocarbamate (SDDC) and hexamethyleneammonium (HMA) — hexamethylenedithiocarbamate (HMDC), separated by HPLC and determined by UV-PCO-CVAAS (ultra violet, post column oxidation, cold vapour atomic absorption spectrometry). The standard deviations are in the range of 6.9 to 11.8%. The recoveries amount to 86%, 78%, 88%, 83%, 79% and 84% for methyl-, ethyl-, methoxyethyl-, ethoxyethyl-, phenyl- and inorganic mercury for the enrichment from 300 ml water samples. The detection limit for methyl mercury is 0.5 ppt. This new on-line preconcentration procedure has been tested with rain, drinking, surface and process water samples.

Determination of neutral chlorinated extractable organic compounds in water samples using large volume on‐column injection capillary gas chomatography–mass spectrometry

AbstractAn automated large volume on‐column injection technique (LOCI) for capillary gas chromatography – mass spectrometry, GC‐MS, with solvent divert and heated retention gap technology has been used to simplify the method for determining sixteen neutral chlorinated extractable compounds (NCEC) in industrial plant process water samples at a level of 10 ng/L. According to the simplified procedure, 30 mL of water sample is extracted with 5 mL hexane, and 100 μL of the extract analyzed by combining large volume on‐column injection with mass‐selective detection operated in the selected ion monitoring mode. This combination has enabled simplification of the sample preparation and analysis procedures and provided a fast, labor‐saving technique for analyzing water samples. Simplifications include significant reduction of sample and eluent volumes during extraction, and elimination of the Kuderna‐Danish evaporative concentration step. The latter simplification has not only resulted in significant time savings, both during the analysis and for subsequent glassware cleaning; analyte losses and the introduction of contaminants and artifacts which may occur during this step have also been eliminated.System behavior, e.g. linearity of detector response, method detection limit, and reproducibility, were evaluated for all sixteen analytes using spiked water samples in the lower ng/L range. The response of the mass detector is linear in the range 5–20000 ppt for all sixteen NCEC investigated. Injection of 100 μL of sample using LOCI makes it possible to achieve an instrument detection limit in the ppt range. The calculated method detection limits are similar to those of the instrument precision and are lower than the required method detection limit of 10 ppt.Extraction efficiency has been maximized by optimizing sample‐to‐solvent ratio and extraction time. The extraction efficiency seems to be independent of sample‐to‐solvent ratio in the range of 2. 5 to 6 and increasing the extraction time from 25 to 120 minutes resulted in no significant increase in efficiency. Extraction efficiency also seems to be independent of the concentration of analyte in the water samples. The simplified procedure presented here was automated by means of a laboratory robot and used to generate all the extraction data reported in this manuscript.

Scanning Electron Microscopy: Application in the Identification of Diatoms in Cases of Drowning

A simple and rapid method is described for processing organ and water samples for the identification of diatoms so that they can be studied and recorded for taxonomic and diagnostic purposes. Samples are treated with concentrated nitric acid; the fluid obtained is centrifuged, and its sediment is dried, coated, and examined under the scanning electron microscope. The method does not alter the morphology of diatoms and allows the study of freshwater and seawater species present in the organs of bodies found in the water, making possible the diagnosis of drowning under specific conditions.

Die sogenannte Rübenzieherlähmung - eine heute seltene Differentialdiagnose

This is a report on a student of biology of 25 years of age who presented with left-sided pareses in the innervated area of the n. peronaeus communis after having remained in a squatting position for several hours for withdrawing and processing water samples. Aspects of differential diagnosis are discussed with particular reference to the so-called turnip-harvester's pressure palsy syndrome, a neuropathy triggered by occupational stress caused by out-dated plucking or digup methods for beets and potatoes. This syndrome is now rare, and the authors deliberate on its etiology.

Improved separations procedures for isolating 2,3,7,8-TCDD and 2,3,7,8-TCDF from chemically-complex aqueous and solid sample martrices and for definitive quantitation of these isomers at ppq to ppt concentrations

An analytical procedure has been developed and validated for quantitatively measuring 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 2,3,7,8-tetrachlorodibenzofuran (TCDF) present at parts-per-trillion (ppt) to parts-per-quadrillion (ppq) concentrations in various paper manufacturing process and waste water samples.