Some Toxic Constituents of Chlorination-Stage Effluents from Bleached Kraft Pulp Mills

1981 ◽  
Vol 38 (7) ◽  
pp. 739-743 ◽  
Author(s):  
A. B. McKague
Keyword(s):  
Gas Chromatography ◽  
Rainbow Trout ◽  
Kraft Pulp ◽  
Pulp Mill ◽  
Salmo Gairdneri ◽  
Pulp Mills ◽  
Juvenile Rainbow Trout ◽  
Bleached Kraft Pulp ◽  
Toxic Materials ◽  
Kraft Pulp Mills

Constituents responsible for the toxicity of a sample of bleached kraft chlorination-stage effluent to juvenile rainbow trout (Salmo gairdneri) were investigated. Tetrachlorocatechol, 3,4,5-trichlorocatechol, and 2,6-dichlorohydroquinone were identified and evidence was obtained for the presence of other chlorodihydroxybenzenes in toxic acidic fractions of the sample. Concentrations of 0.46 mg/L 3,4,5-trichloro- and 0.74 mg/L tetrachloro-catechol were estimated in the sample by analytical gas chromatography. Toxic materials in the nonacidic fraction were not identified although the nontoxic dichloromethyl methyl sulfone was isolated.Key words: chlorination-stage effluent, toxicity, pulp mill, chlorocatechols, chlorodihydroxybenzenes

Characterization of odorous compounds from bleached kraft pulp mill effluent

1995 ◽  
Vol 31 (11) ◽  
pp. 35-40 ◽  
Author(s):  
B. G. Brownlee ◽  
S. L. Kenefick ◽  
G. A. MacInnis ◽  
S. E. Hrudey
Keyword(s):  
Gas Chromatography ◽  
Kraft Pulp ◽  
Pulp Mill ◽  
Dimethyl Disulfide ◽  
Gas Chromatography Mass Spectrometry ◽  
Pulp Mill Effluent ◽  
Kraft Pulp Mill ◽  
Bleached Kraft Pulp ◽  
Methyl Phenyl Sulfide ◽  
Library Spectrum

Odour compounds in extracts of bleached kraft pulp mill effluent (BKME) have been characterized by olfactory gas chromatography (OGC) and gas chromatography-mass spectrometry. A variety of sulfury odours was detected by OGC in addition to woody and pulp mill-like odours. Three sulfur compounds were identified by comparison of retention times and partial mass spectra with authentic standards: dimethyl disulfide, 3-methylthiophene and thioanisole (methyl phenyl sulfide). Typical concentrations in BKME were 1, 0.05, and 0.5 μg/l, respectively. Their odour intensity is relatively low and they were not detected by OGC. Dimethyl trisulfide was tentatively identified by comparison of its partial mass spectrum with a literature (library) spectrum. Its concentration in BKME was estimated at 0.5-2 μg/l. It corresponded to a skunky odour in the OGC profiles. Efforts to identify another odour peak, eluting just after 3-methylthiophene, with a pronounced alkyl sulfide odour were unsuccessful.

Fate of phosphorus in the recovery cycle of the kraft pulping process

TAPPI Journal ◽  
2020 ◽  
Vol 19 (3) ◽  
pp. 139-148
Author(s):  
MARYAM SADEGH MOUSAVI ◽  
NIKOLAI DEMARTINI
Keyword(s):  
Kraft Pulp ◽  
Pulp Mill ◽  
Field Studies ◽  
Kraft Pulping ◽  
Pulp Mills ◽  
Recovery Cycle ◽  
Green Liquor ◽  
Green Liquor Dregs ◽  
Kraft Pulp Mills ◽  
Negative Effect

The accumulation of nonprocess elements in the recovery cycle is a common problem for kraft pulp mills trying to reduce their water closure or to utilize biofuels in their lime kiln. Nonprocess elements such as magne-sium (Mg), manganese (Mn), silicon (Si), aluminum (Al), and phosphorus (P) enter the recovery cycle via wood, make-up chemicals, lime rock, biofuels, and process water. The main purge point for these elements is green liquor dregs and lime mud. If not purged, these elements can cause operational problems for the mill. Phosphorus reacts with calcium oxide (CaO) in the lime during slaking; as a result, part of the lime is unavailable for slaking reactions. The first part of this project, through laboratory work, identified rhenanite (NaCa(PO4)) as the form of P in the lime cycle and showed the negative effect of P on the availability of the lime. The second part of this project involved field studies and performing a mass balance for P at a Canadian kraft pulp mill.

scholarly journals Method for analysis of ClO2 and Cl2 air emissions from pulp mill

2019 ◽  
Vol 34 (1) ◽  
pp. 19-27
Author(s):  
Kimona Häggström ◽  
Magnus Gunnarsson ◽  
Katarina Bremert-Jirholm ◽  
Nina Simic
Keyword(s):  
Chlorine Dioxide ◽  
Analytical Method ◽  
Kraft Pulp ◽  
Pulp Mill ◽  
Air Emissions ◽  
Pulp Mills ◽  
Limit Of Quantification ◽  
Regulatory Standards ◽  
Low Concentrations ◽  
Kraft Pulp Mills

Abstract Chlorine dioxide is commonly used as a bleaching agent in kraft pulp mills. Scrubbers are required to remove any remaining ClO2 from the plant tail gases. To control the air emissions of chlorine compounds, chlorine dioxide and chlorine contents must be monitored to ensure that the strict regulatory standards are met. However, the currently used analytical method is not suitable for detection of low concentrations of chlorine and chlorine dioxide. A new method for measuring chlorine dioxide and chlorine emissions was developed, which ensures compliance with the stringent requirements imposed by the authorities. The two species could be measured separately with a limit of quantification of 3 ppm. The method was robust and easy to use in the pulp mill environment and it was validated both in the laboratory and the field. The specificity of the method was demonstrated, Cl2 analysis was not sensitive to the presence of ClO2 and vice versa. The uncertainty (±2×RSD) of the analytical method in the field was estimated from duplicate measurements performed in the range of 3–500 ppm for ClO2 and 3–300 ppm for Cl2, and was found to be ±20 % and ±10 %, respectively. Possible interferences in the analytical method are also discussed.

The influence of anoxic conditioning of sludge on enhanced AOX (adsorbable organic halogen) removal in aerobic biological treatment systems

1997 ◽  
Vol 35 (2-3) ◽  
pp. 77-84 ◽  
Author(s):  
Liu Hua-Wu ◽  
Steven N. Liss ◽  
D. Grant Allen
Keyword(s):  
Activated Sludge ◽  
Biological Treatment ◽  
Kraft Pulp ◽  
Pulp Mills ◽  
Batch Experiments ◽  
Bleached Kraft Pulp ◽  
Organic Halogen ◽  
Kraft Pulp Mills ◽  
Aox Removal ◽  
Activated Sludge Systems

The increasingly stringent limits on the discharge of adsorbable organic halogen (AOX) from bleached kraft pulp mills have resulted in a need to optimize the performance of biological wastewater treatment systems with respect to the removal of these compounds. To investigate whether anoxic conditioning of sludge can enhance AOX removal in activated sludge systems, a series of batch experiments was conducted where reactors were seeded with various proportions of activated and anoxic-conditioned sludges. AOX removal was found to be significantly enhanced through the addition of anoxic-conditioned sludge to activated sludge, resulting in overall AOX removal of up to 75%. The extent of enhancement ranged from 3 to approximately 10% as the conditioning time was increased from 5 to 20 days. The benefit then declined as the conditioning times increased further beyond 20 days and up to 30 days. The effect of conditioning time on COD removal followed a similar trend as for AOX removal. An optimal AOX removal was achieved when the proportion of conditioned sludge within the biomass was 30%. A good correlation between the enhanced AOX removal and increasing levels of facultative bacteria developed in the conditioned sludge was observed. The addition of sulphate into the sludge during conditioning further increased the enhancement of AOX removal when compared to sludges conditioned under nitrogen.

Formation of pirssonite in green liquor handling systems

TAPPI Journal ◽  
2013 ◽  
Vol 12 (7) ◽  
pp. 33-41 ◽  
Author(s):  
TASNUVA ZAKIR ◽  
HONGHI TRAN ◽  
VLADIMIROS G. PAPANGELAKIS
Keyword(s):  
Sodium Carbonate ◽  
Kraft Pulp ◽  
Pulp Mill ◽  
Pulp Mills ◽  
Hard Scale ◽  
Kraft Pulp Mill ◽  
Green Liquor ◽  
Kraft Pulp Mills ◽  
Alkali Salts

The formation of pirssonite is commonly believed to be the cause of hard-scale buildup in green liquor handling systems in kraft pulp mills. The precipitation occurs when the concentration of sodium carbonate in the liquor exceeds the solubility of pirssonite. A laboratory study was conducted to systematically determine the causticizing conditions under which pirssonite precipitates. The results confirmed literature data showing that the solubility of pirssonite increases with temperature but decreases with increased concentrations of sodium carbonate and other sodium salts present in the green liquor. The solubility data obtained were used to create a database for pirssonite formation in OLI, a thermodynamic program for predicting phase stabilities of alkali salts in aqueous solutions. The OLI program, with the newly created database, was subsequently used to generate a series of pirssonite solubility curves in terms of saturated total titratable alkali that can be used as operational guidelines to prevent pirssonite precipitation and hard-scale formation in green liquor handling systems. A case study was performed using these solubility curves to explain the occurrence of the pirssonite deposition problem at a kraft pulp mill.

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