Removal of individual sterols during secondary treatment of pulp mill effluents

2012 ◽  
Vol 47 (1) ◽  
pp. 56-65 ◽  
Author(s):  
Zahid Mahmood-Khan ◽  
Eric R. Hall

Analysis of plant sterols in pulp mill effluents is complex and several investigations have combined wood extractives with sterols or have reported total sterols collectively. The present study exclusively focuses on the fate of individual sterols generated in pulp and paper manufacturing as they pass through activated sludge biotreatment system. Before secondary treatment the pulp mill effluents contained 33% ß-sitosterol, 26% campesterol, 22% ß-sitostanol, 17% stigmasterol and 2% ergosterol (1,000–1,800 μg/L mean total sterols). After treatment, the effluents contained 44% ß-sitosterol, 22% campesterol, 18% ß-sitostanol, 14% stigmasterol and 2% ergosterol (176–428 μg/L mean total sterols). Each sterol fraction showed different removal efficiency. ß-Sitosterol, the major fraction, was removed relatively poorly (65%) while campesterol was removed most efficiently (81%) compared with the removal of other fractions (ß-sitostanol 74% and stigmasterol 64%). The differential removal of sterol fractions altered the sterol profile during different stages of the secondary treatment. Owing to its poor removal, ß-sitosterol is the most persistent fraction in treated/untreated pulp mill effluents. Typically, 21% of the incoming sterols were contained in secondary effluents and 23% in waste sludge without biodegradation. Optimizing the design/operation of treatment systems for removal of ß-sitosterol and stigmasterol would improve the performance of effluent treatment facilities.

1991 ◽  
Vol 24 (3-4) ◽  
pp. 189-198 ◽  
Author(s):  
V. P. Lankinen ◽  
M. M. Inkeröinen ◽  
J. Pellinen ◽  
A. I. Hatakka

Decrease of adsorbable organic chlorine (AOX) is becoming the most important criterion for the efficiency of pulp mill effluent treatment in the 1990s. Two methods, designated MYCOR and MYCOPOR which utilize the white-rot fungus Phanerochaete chrysosporium have earlier been developed for the color removal of pulp mill effluents, but the processes have also a capacity to decrease the amount of chlorinated organic compounds. Lignin peroxidases (ligninases) produced by P. chrvsosporium may dechlorinate chlorinated phenols. In this work possibilities to use selected white-rot fungi in the treatment of E1-stage bleach plant effluent were studied. Phlebia radiata. Phanerochaete chrvsosporium and Merulius (Phlebia) tremellosus were compared in shake flasks for their ability to produce laccase, lignin peroxidase(s) and manganese-dependent peroxidase(s) and to remove color from a medium containing effluent. Softwood bleaching effluents were treated by carrier-immobilized P. radiata in 2 1 bioreactors and a 10 1 BiostatR -fermentor. Dechlorination was followed using Cl ion and AOX determinations. All fungi removed the color of the effluent. In P. radiata cultivations AOX decrease was ca. 4 mg l−1 in one day. Apparent lignin peroxidase activities as determined by veratryl alcohol oxidation method were negligible or zero in a medium with AOX content of ca. 60 mg l−1, prepared using about 20 % (v/v) of softwood effluent. However, the purification of extracellular enzymes implied that large amounts of lignin peroxidases were present in the medium and, after the purification, in active form. Enzyme proteins were separated using anion exchange chromatography, and they were further characterized by electrophoresis (SDS-PAGE) to reveal the kind of enzymes that were present during AOX decrease and color removal. The most characteristic lignin peroxidase isoenzymes in effluent media were LiP2 and LiP3.


2002 ◽  
Vol 37 (1) ◽  
pp. 21-48 ◽  
Author(s):  
Richard P. Scroggins ◽  
Jennifer A. Miller ◽  
Anne I. Borgmann ◽  
John B. Sprague

Abstract Sublethal toxicity tests successfully measured the improved quality of pulp mill effluents from the first cycle of environmental effects monitoring (1992–1996) to the second cycle (1997–2000). Test endpoints showed notable shifts to higher concentrations (less toxic). During the second cycle of monitoring, significantly more tests showed no effect in full-strength effluent. Five case studies were considered as part of this exercise. Most of the improvement came with installation of secondary treatment. Twelve Ontario mills with secondary treatment showed reduced toxicity, compared to results with primary treatment. All 29 sets of sublethal data showed higher IC25s during the second cycle, and 23 of these differences were statistically significant. Any other changes between the two cycles of study caused only marginal overall improvement in toxicity, judging by 12 freshwater mills in British Columbia which had secondary treatment during both cycles. Sublethal tests successfully predicted the zone of potential effect in receiving water, agreeing with effects observed in biological surveys. Overlapping zones from multiple discharges could also be demonstrated. In a situation near Niagara Falls, sublethal tests estimated the proportions of toxic loading that four mills contributed to one water body. The prediction was realistic; the actual toxicity found for a mixed effluent was 57% of that predicted from separate toxicities. The conservative prediction agrees with the usual less-than-additive sublethal action of combined toxicants.


1992 ◽  
Vol 49 (1) ◽  
pp. 166-172 ◽  
Author(s):  
Eric Lindesjöö ◽  
Jan Thulin

Increased prevalences of a skeletal deformity affecting the skull of northern pike (Esox lucius) were related to three pulp mills in the Gulf of Bothnia, Sweden. At one mill the later disappearance of the disease, from an original prevalence of 35%, coincided with a marked improvement of effluent treatment. A typical deformed pike showed distinct upward bending of the jaws. The disease always affected the anterior part of the parasphenoid and the frontal bones. In the most severe cases the nasal, vomer, and medial rostral were also deformed. The degree of deformation was expressed as the ratio between two measurements made on the skull.


1999 ◽  
Vol 40 (11-12) ◽  
pp. 195-200 ◽  
Author(s):  
P. Harila ◽  
V.-A. Kivilinna

An activated sludge process is an effective tool against effluent emissions in a pulp mill. It has only a few features which can be regarded deficiences. One of them is that effluent treatment of a modern pulp mill creates some 10-20 tonnes dry solids of biosludge per day. This sludge is difficult to burn due to its high moisture content. The most common way is to mix biosludge with primary sludge, to dewater the mixture in presses and finally to burn it in a solid fuel boiler. This type of sludge treatment incurs rather high costs and does not produce any net energy. Also combustion emissions vary depending on the boiler type. The Metsä-Botnia Kemi Pulp Mill was the first mill in the world to burn biosludge in a recovery boiler. The system start-up was in 1993 and it has been in operation ever since. Mechanically dewatered biosludge is mixed with weak black liquor and concentrated in a conventional evaporation plant equipped with a pressurized superconcentrator unit. In a modern recovery boiler, firing conditions are well controlled and monitored. Better emission control than in most bark fired boilers is achieved. Accumulation of nonprocess elements, corrosion, plugging, scaling and some other operational problems were expected. A lot of experience has been gathered during the years of operation and reviewed in this presentation. The achieved benefits of the system are discussed. Disposal of biosludge in a recovery boiler offers an economically and environmentally attractive alternative. Probably the best evidence from this is the fact that Metsä-Botnia has applied the same process solution in the recent reconstruction of the recovery departments at the Jouteno Mill.


2020 ◽  
Vol 35 (4) ◽  
pp. 577-588
Author(s):  
Sebastian España Orozco ◽  
Philipp Zeitlinger ◽  
Karin Fackler ◽  
Robert H. Bischof ◽  
Antje Potthast

AbstractThe extraction of lipophilic wood extractives from pulp and paper process waters proves to be a challenging task, due to harsh and alternating process and sample conditions. This study has determined the potential use of polymeric sorbents for solid-phase extraction (SPE) and compared to classical silica-based reversed-phase packed columns, with polymeric hydrophilic-lipophilic balanced (HLB) cartridges being the sorbent with the most potential. Recovery functions were obtained with an internal standard mixture representative for the main lipophilic wood extractive groups, which are fatty acids and alcohols, sterols, sterol esters and triglycerides. The impact of pH, sample volume and sample matrix, expressed as TOC and cations, on the retention behavior of lipophilic extractives during SPE of industrial samples were determined with polymeric HLB sorbent. High variations in the composition of pulp mill matrices led to different optimal extraction conditions. Thus, a new SPE protocol was developed, which bypasses matrix interferences and omits the loss of analytes due to sample preparation. The method is applicable to different pulp mill effluents with large discrepancies in pH and sample matrices, resulting in recoveries >90 % with RSD <5 % for all lipophilic wood extractives.


Sign in / Sign up

Export Citation Format

Share Document