Polychlorinated dibenzothlophenes in bleached pulp mill effluents

Polychlorinated dibenzothiophenes, PCDBTs, have been analysed with HRGC/HRMS from different bleached pulp mill effluents. 2,3,7,8-TeCDBT was found to be the dominating TeCDBT isomer in some samples. The estimated concentrations of the TeCDBTs in the samples were < 1 to 60 pg/L. PeCDBTs and other higher chlorinated PCDBTs were not found (< 1 pg/L).     

A laboratory exposure procedure for screening pulp and paper mill effluents for the potential of causing increased mixed function oxidase activity in fish

To better understand the relationships between pulp manufacturing processes and mixed function oxidase (MFO) enzyme induction in fish, a practical and standardized exposure procedure is required. This study was undertaken to develop a laboratory-based exposure procedure to quantify the relative MFO induction potencies of different types of pulp and paper mill effluents. One major consideration in developing the procedure was to ensure that the protocol was practical so that tests could be performed in a short time, with small volumes of effluents and using simple experimental conditions. A series of concentration-response and time-course experiments were conducted to find the minimum time and effluent concentration which could distinguish the ability of different effluents to cause significant MFO induction in rainbow trout in the laboratory. Experiments were also conducted to determine the effects of biotic and abiotic factors such as loading density, fish size and feeding regime. This study showed that the exposure of rainbow trout in the laboratory to 10% concentration of secondary-treated effluent for 96 h caused significant increases in hepatic MFO activity. The magnitude of MFO induction was comparable to other field and laboratory observations. While fish size, loading density and feeding regime were found to affect the test results, consistent responses within a laboratory using this protocol are possible, provided that these factors are standardized. Therefore, the short-term exposure approach described in this paper could be a relevant tool for assessing the ability of different types of pulp and paper mill effluents to cause MFO induction in fish.     

Determining algal-available phosphorus in pulp and paper mill effluents: algal assays vs routine phosphorus analyses

We determined the potentially algal-available P (P(aa)) in pulp and paper mill effluents by two bioassay techniques (a dual-culture assay and a batch approach) and compared it with chemically analysed P (total P, total dissolved P, reactive P, dissolved reactive P and dissolved hydrolysable P). The mean P(aa) given by the dual-culture assay was within a 40% range of that given by the batch approach. The P(aa) obtained by both bioassays differed from total P. Dissolved reactive P appeared to be the most readily available chemical P fraction, but other P fractions also contributed to P(aa). The analysis of reactive P, which involves direct staining of an unfiltered sample, best approximated the P(aa) given by the dual-culture assay (relative error 9%). The results suggest that assessment of eutrophying effluent P can be improved by analysing simple chemical P fractions in wastewater. The fractions to be analysed, however, may be site specific.     

Fish community responses to pulp and paper mill effluents at the southern Lake Saimaa, Finland.

The fish community in sublittoral and profundal waters, at stony shores, and densities of vendace larvae were studied in the southern Lake Saimaa, Finland. The objective was to investigate the possible recovery of fish populations after modernizations at the pulp and paper mills discharging into the lake. Sublittoral and profundal waters were studied by gill net trial fishings, stony shores by electrofishing, and vendace larvae by beach seine. The research area was divided in a polluted (0.5-4.0% effluent), an intermediate (0.1-0.5%) and a 'clean' reference area. The fish community in sublittoral and profundal waters in the lake was dominated (> 60%) by perch and roach. Relative abundance of fish was highest in the polluted area, and lowest in the reference area. The number of species caught was similar among areas. The abundance of bleak and ruffe was highest in the polluted area, while the abundance of vendace and whitefish was highest in the intermediate and reference area. The fish fauna of stony shores in the lake was dominated by bullhead, stone loach and minnow, densities were lowest at polluted shores and highest in the intermediate area. Minnow, apparently a more sensitive species to pulp mill effluents, were not caught at the most polluted shores. The catch of vendace larvae was similar among areas, larvae were also caught in the vicinity of the mills. Compared with before the modernization at the mills, the relative abundance of perch in the polluted area was increased, ruffe decreased, while populations of whitefish and vendace showed signs of recovery. These changes may be explained by the reduced nutrient load and toxicicity of pulp mill effluents. At present, the fish community in the polluted area can be considered typical for a moderate eutrophication.     

Betulinol and wood sterols in sediments contaminated by pulp and paper mill effluents: dissolution and spatial distribution

The goal was to determine dissolution potency of betulinol and wood sterols (WSs) from pulp and paper mill-contaminated sediments and the current stratification for assessment the load due to potential erosion in the river-like watercourse. Both compounds are wood extractives, which may be toxic to benthos and fish. This research continues a study in which other wood extractives, resin acids and their derivative, retene, were analysed. Sediments were collected from 1, 3.5, 12, 15, and 33 km downstream from the pulp and paper mills, and from 2 upstream reference sites. The dissolution potency into sediment–water elutriates (1?+?4?v/v) was studied by two agitation times and temperatures. The vertical amounts of extractives were determined from the uppermost 20 cm of sediment. The amounts of extractives potentially released were estimated from the sediment layers 0–2 and 2–5 cm by using spatial interpolation. According to the interpolation, the total amount of betulinol and β-sitosterol was calculated as kg/ha in the whole sediment area. Significant concentrations of betulinol (1,666 μg/g, dw) and WSs (2,886 μg/g, dw) were measured from the sediments. According spatial interpolation, the highest calculated amount of betulinol (4,726 kg/ha) and that of the most abundant WS, β-sitosterol (3,571 kg/ha), were in the lake where the effluents were discharged. In the dissolution experiment, the highest concentration of betulinol in sediment (0–10 cm) and elutriate was 412 μg/g (dw) and 165 μg/l, respectively. For WSs, concentrations were 768 μg/g (dw) in sediment and 273 μg/l in elutriate. In a worst-case scenario, betulinol may be desorbed to water in concentrations which are hazardous to aquatic animals. Instead WSs are not a risk in this study area. The amount of desorption varied depending on the concentration of contaminants in sediment, the nature of disturbance, and the sediment organic carbon content.     

Toxicity to Microtox, micro-algae and duckweed of effluents from the Bai Bang paper company (BAPACO), a Vietnamese bleached kraft pulp and paper mill

Toxicity of the combined effluent as well as effluents from different production units of BAPACO, a Vietnamese bleached kraft integrated pulp and paper mill, was studied using three ecotoxicological tests: Microtox, the micro-alga, Selenastrum capricornutum, and the duckweed, Lemna aequinoctialis. Physico-chemical characteristics of the effluents were also analyzed. Due to unstable operating conditions of the mill, a number of samples taken at different monitoring periods from each effluent were tested, in order to get statistically reliable ranges and averages of toxicity characteristics. For the mill combined effluent, it was found that the micro-algae were the most sensitive followed by Microtox bacteria, while duckweed was not sensitive. Microtox tests showed that the bleaching filtrate from the chlorination stage (C-stage) was the most toxic among all effluents in the mill. The combined effluent from the bleaching plant contributed the largest TEF (Toxicity Emission Factor) to the toxicity balance of the whole BAPACO combined effluent. A less-than-additive mode of toxicity was obtained. In spite of high pollution loads, e.g. BOD, COD, SS, to the Red River, the toxicity of the effluent was considered to be low. However, during periods of low river water sublethal toxic effects on the biota may be expected.     

Polychlorinated dibenzo-p-dioxins and dibenzofurans in paper making from a pulp mill in China

An extensive investigation on the input, formation and fate of PCDD/Fs in a pulp mill using reeds as raw materials in China was carried out. The main PCDD/Fs input in the production process came from reeds, which may be contaminated by PCDD/Fs from sodium pentachlorophenate to control snailborne schistosomiasis. High levels of I-TEQ in the products were observed.     

Changes in character of organics in the receiving environment of effluent from a sulphite pulp mill

Purpose

The characteristics of organics in sulphite pulp mill effluent and in the receiving environment of effluent discharge were investigated to assess the basis for the persistence or attenuation of colour.

Methods

Characterization of organics was conducted through determination of SUVA, specific colour, and molecular weight distribution of organics using high performance size exclusion chromatography and by solid-state ¹³?C cross polarization (CP) NMR. The characteristics of organics from mill wastewater before and after secondary aerobic treatment, followed by lime treatment and from the receiving environment, an enclosed brackish lake were compared. Changes in the character of organics in lake water over a period of 14?years were studied in the context of changes in mill processing and climate impacts.

Results

High colour in mill effluent and in receiving waters correlated with high SUVA and specific colour levels, high molecular weight range and aromatic content. Conversely, lake waters with low colour had UV absorbing compounds of much lower molecular weight range and low relative abundance of aromatic compounds. Attenuation of colour and changes in the character of organics in the receiving environment coincided with increased concentrations of metal cations.

Conclusions

These increased concentrations appear to be due to the effects of climate change, lake management and their presence in mill effluent, with subsequent discharge to the lake. Attenuation of colour was found to be predominantly through removal of high molecular weight aromatic compounds where the removal processes could be through adsorption and co-precipitation with divalent metals, as well as through dilution processes.     

Determination of dibenzo-p-dioxin (DBD) and dibenzofuran (DBF) in paper pulp mill defoamer additives and in paper pulp samples

An analytical procedure has been developed for quantitatively measuring dibenzo-p-dioxin (DBD) and dibenzofuran (DBF) present at part-per-billion levels in paper mill defoamers and paper pulp using gas chromatography coupled with either low resolution mass spectrometry (GC-LRMS) or high resolution mass spectrometry (GC-HRMS).     

Assessing potential risks to wildlife and sportsmen from exposure to dioxin in pulp and paper mill sludge spread on managed woodlands

Potential human and wildlife exposures to TCDD in landspread pulp and paper mill sludge in the State of Maine were evaluated by means of a human health and an ecological risk assessment methodology. The highest historical concentrations of TCDD reported for these sludges do not present a risk to American woodcock, selected as an indicator species for this analysis. Concentrations of TCDD as high as 50 ppt in soil are not likely to produce adverse effects in the embryonic/hatchling stage of the woodcock. This soil concentration of TCDD does not present a significant risk to sportsmen and their families that may consume birds which inhabit these sites.     

制浆造纸废水生化出水的混凝处理研究

研究了硫酸铝和三氯化铁对制浆造纸废水生化出水的处理效果.研究发现,不调节原水pH值,硫酸铝投加量为600 mg/L或三氯化铁投加量为300mg/L时,混凝后废水的COD＜150 mg/L,色度＜50倍,出水均符合现阶段排放标准.混凝剂比较发现,在最佳反应条件下,2种混凝剂的处理效果相当,但硫酸铝混凝的成本低于三氯化铁....     

Reproductive success and chlorinated hydrocarbon contamination in tree swallows (Tachycineta bicolor) nesting along rivers receiving pulp and paper mill effluent discharges

The insectivorous tree swallow was chosen as an indicator species to investigate the uptake of pulp mill-related chlorinated hydrocarbons from emergent aquatic insects. Nest box populations were monitored for reproductive success at locations upstream and downstream of pulp mills on two river systems in British Columbia, Canada. Also, 16-day-old nestlings were collected and analysed for polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), pesticides, chlorophenols and chloroguaiacols. Most reproductive parameters were not different between populations at upstream and downstream locations, and were equivalent to or greater than those recorded for other tree swallow populations. Chlorinated hydrocarbon contamination of nestlings was low at all sites. The highest tissue concentrations were detected downstream of pulp mills on the Fraser River, where PCDD and PCDF patterns along with the presence of pentachlorophenol (PCP) suggested that the primary source of contaminants was past use of PCP for timber preservation. Although the absolute tissue concentration of contaminants was less, the toxic concentration (as estimated with I-TEQs) was greatest in nestlings downstream of a pulp mill on the Thompson River. The proportionately larger contributions from 2,3,7,8-TCDF and PCB-77 elevated these TEQs in comparison to other populations. Nest success was the one reproductive measure that showed substantial reductions in downstream populations on both rivers; however, there was little indication that nest failures were the direct result of contamination. Failures were largely due to parental abandonment, and, while poor parental attentiveness and nest abandonment have been associated with chlorinated hydrocarbon tissue concentrations in other studies, our 1-year assessment was insufficient to establish any link with pulp mill effluent exposure. Nestling growth models showed some subtle differences in growth patterns between nest box populations on the two rivers, but an association with pulp mill effects on aquatic insect prey availability was not established.     

Investigation of pathogenic Escherichia coli and microbial pathogens in pulp and paper mill biosolids.

Biosolids produced from pulp and paper mill wastewater treatment have excellent properties as soil conditioners, but often contain high levels of Escherichia coli. E. coli are commonly used as indicators of fecal contamination and health hazard; therefore, their presence in biosolids causes concern and has lead to restrictions in land-spreading. The objectives of this study were to determine the following: (1) if E. coli from the biosolids of a wastewater-free pulp and paper mill were enteric pathogens, and (2) if other waterborne microbial pathogens were present. E. coli were screened for heat-labile and heat-stable enterotoxin and verocytotoxin virulence genes using a polymerase chain reaction. Ten isolates were also screened for invasion-associated locus and invasion plasmid antigen H genes. None of the 120 isolates carried these genes. Tests for seven other microbial pathogens were negative. Effluents and biosolids from this mill do not contain common microbial pathogens and are unlikely to pose a health hazard.     

Catalytic wet oxidation of the pretreated synthetic pulp and paper mill effluent under moderate conditions

In the present study, catalytic wet oxidation (CWO) was investigated for the destruction of organic pollutants in the thermally pretreated effluent from a pulp and paper mill under moderate temperature and pressure conditions. The thermal pretreatment studies were conducted at atmospheric pressure and 368K using copper sulfate as a catalyst. The thermal pretreatment reduced COD by about 61%. The filtrate of the thermal pretreatment step was used at pH 8.0 for CWO at 383-443K temperature and a total pressure of 0.85MPa for 4h. Catalysts used for the reaction include copper sulfate, 5% CuO/95% activated carbon, 60% CuO/40% MnO(2), and 60% CuO/40% CeO(2). Maximum COD reduction was found to be 89% during CWO step using 5% CuO/95% activated carbon with a catalyst loading of 8gl(-1) at 443K and 0.85MPa total pressure. Overall COD reduction for the pretreatment and the CWO was found to be 96%. Besides this, 60% CuO/40% CeO(2) catalyst also exhibited the similar activity as that of obtained with 5% CuO/95% activated carbon catalyst at 423K temperature and 0.85MPa total pressure. The pH of the solution during the experimental runs decreases initially due to the formation of carboxylic acid and then increases due to the decomposition of acids.     

Effects of solar radiation on the fluorescence properties and molecular weight of fulvic acids from pulp mill effluents

The pulp and paper industry generates large volume of wastewater that adversely affects water resources. Lignin derived macromolecular compounds, similar to natural humic substances, are the main waste products in the pulp mill effluents. The UV-Vis and fluorescence spectroscopies were used to assess the effect of solar exposition on fulvic acids from a kraft pulp mill effluent. Solar irradiation of the solutions of these fulvic acids caused solution acidification and decay both in the UV-Vis absorbance and in the fluorescence. This decay was not the same for the whole spectra but pointed to the selective photodegradation of lignin typical structures. Furthermore, by sequential ultrafiltration it was found that during irradiation, the high-molecular weight fractions were destroyed and low-molecular-weight constituents, potentially more able to penetrate the cell membranes of living organisms were formed. Photodegradation of macromolecular organic matter from a kraft pulp mill effluent may be a key process occurring in natural waters that modifies the physicochemical properties of such effluents.     

Identification and level estimation of chlorinated neutral aromatic sulfur compounds and their alkylated derivatives in pulp mill effluents and sediments

Seven effluent samples from a modern pulp mill, in which chlorine and chlorine dioxide bleaching is used, and five sediment samples from the recipient watercourse were investigated for polychlorinated dibenzothiophenes (PCDBTs), polychlorinated thianthrenes (PCTAs), polychlorinated diphenylsulfides (PCDPSs) and for alkylated derivatives of these. Mainly di-, tri-, tetra- and pentachlorinated congeners were studied. Particles and filtrates from the effluents were analyzed separately. The concentration levels of the nonalkylated compounds were found to be higher in the filtrates than in the particles. Trichlorinated dibenzothiophenes and thianthrenes were found as the major congeners. Pentachlorinated derivatives were not found. Alkylated di- and trichlorodibenzothiophenes were detected in some samples, while alkylated chlorinated thianthrenes and diphenylsulfides were nondetectable. The estimated concentration levels of the compounds detected were in the range of 40–2700 pg/L in the pulp mill effluents and in the range of 2–40 pg/g dry weight in the sediments. Mixtures of methylated di- and trichlorodibenzothiophenes used as references in analyses were prepared from methylchlorobiphenyls. Some new pure model compounds were obtained by HPLC fractionation of the chlorination mixture of dibenzothiophene. Structures of these were determined by ¹H NMR.     

Chlorinated fluorenes and alkylfluorenes in bleached kraft pulp and pulp mill discharges

The occurrence and levels of polychlorinated fluorenes (PCFLs), methylfluorenes (C₁-PCFLs) and dimethylfluorenes (C₂-PCFLs) were studied by high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS) in hardwood and softwood pulp, effluent and biosludge from a bleached kraft mill. Semiquantitative concentrations of these compounds were estimated using selected ion monitoring and a mass spectral resolution of 10,000. The identification of PCFLs and C₁-PCFLs was confirmed by the chlorination mixtures of fluorene and 2-methylfluorene.

Several congeners were found for each compound groups studied and isomer patterns were similar in bleached pulp and biosludge. The approximated sum levels of di- and trichloro isomers of PCFLs, C₁-PCFLs and C₂-PCFLs in the biosludge were about 2, 5 and 4 ng/g dry weight (dw), respectively. The levels of the corresponding compounds in the softwood pulp were 0.5, 0.8 and 0.2 ng/g dw, respectively. Of the studied compounds, only C₁-diCFLs (0.01 ng/g dw) were detected in the hardwood pulp. In the effluent, PCFLs were non-detectable, but traces of C₁-diCFLs (0.5 ng/L) and C₂-pentaCFLs (0.06 ng/L) were found. These were observed mainly as dissolved in the filtrate and not as particle-bound.     

Fate of pulp mill effluent compounds in a finnish watercourse

Chloroorganic chemicals emitted from the pulp and paper mill at nekoski in central Finland were monitored for several years. Concentration time series are used for evaluating the environmental fate and the applicability and validity of an exposure models. Fitted elimination rates of 3,4,5-Tri-, 4,5,6-Tri-, Tetrachloroguaiacol and 2,4,6-Trichlorophenol are approx. 0.22 d^-1, or rather the half-lives are approx. 3 days. The elimination is most likely by biodegradation and transport-controlled. For 2,3,6-trichloro-p-cymene, fate simulations indicate significant volatilization and sedimentation. Good agreement is achieved with a one-dimensional steady-state box model, except for concentrations in fish. For a reliable assessment of environmental damage, laboratory experiments, monitoring and simulations need to be in tune.     

Some factors influencing EROD activity in winter flounder (Pleuronectes americanus) exposed to effluent from a pulp and paper mill

EROD (ethoxyresorufin-O-deethylase) activity was determined in winter flounder, a sediment-inhabiting and non-migratory fish species, living near a pulp and paper mill in Newfoundland in relation to temperature, gender, sexual maturity, and lesions in the liver. Samples of liver were taken from fish captured by SCUBA divers at 0 degrees C, 5 degrees C and 16 degrees C. Enzymic activity was detected in fish living only above 0 degrees C. Adult males and juvenile fish had higher levels of EROD activity than prespawning females at 5 degrees C. Macrophage aggregates only or occurring simultaneously with bile ductule hyperplasia and clear cell foci in the liver, did not impair EROD activity but necrosis had a negative effect. Results from this study indicate the importance of water temperature, gender, sexual maturity and liver pathology in assessing EROD activity of fish in biomonitoring programs.     

Advanced oxidation of a pulp mill bleaching wastewater.

The degradation, by several advanced oxidation reactions, of a pulp mill ECF bleaching effluent, was studied. The initial biodegradability of the organic matter present in the effluent, estimated as the BOD5/COD, was low (0.3). When the effluent was submitted to ozonation and to five different advanced oxidation systems (O3/UV, O3/UV/ZnO, O3/UV/TiO2, O2/UV/ZnO, O2/UV/TiO2), the biodegradability increase significantly. After five minutes of reaction, the O3/UV system appears as the most efficient in to transform the organic matter to more biodegradable forms. A similar effect was observed when the effluent was submitted to an activated sludge treatment. The COD, TOC and toxicity reduction correlated well with the biodegradability enhancement after AOPs treatments.