Ultrafiltration and nanofiltration in the pulp and paper industry using cross-rotational (CR) filters

2004 ◽  
Vol 50 (3) ◽  
pp. 229-238 ◽  
Author(s):  
M. Mänttäri ◽  
M. Nyström
Keyword(s):  
Paper Industry ◽  
Pulp And Paper Industry ◽  
Pulp And Paper ◽  
Paper Machine ◽  
High Shear ◽  
Nanofiltration Membranes ◽  
Ph Conditions ◽  
Acidic Waters ◽  
Pre Treatment ◽  
Neutral Conditions

Ultra- and nanofiltration with high shear CR-filters have been utilized for cleaning of clear filtrates and effluents from the pulp and paper industry. The aim was to find out how different nanofiltration membranes operate at high shear conditions. The filtration efficiency of the membranes was evaluated by measuring flux, retention and fouling at various recovery and pH conditions. High fluxes (∼100 L/(m2h)) for nanofiltration membranes were measured when circulation waters from the paper machine were filtered at neutral conditions. In the filtration of discharge of external activated sludge treatment plants we measured fluxes around 150 L/(m2h) even at a concentration factor of 12. The best NF membranes removed over 80% of the organic carbon and of the conductivity and almost completely eliminated the color. With acidic waters fluxes and retentions were significantly lower. The NF270 membrane from Dow and the Desal-5 membranes from Osmonics had the highest flux and retention properties. However, the Desal-5 membrane lost its retention properties slowly, which restricts its use in the high shear CR-filter. CR-nanofiltration can be used in the pulp and paper industry without feed pre-treatment by ultrafiltration. This increases the attractiveness of high shear CR-nanofiltration.

Water circuit closure with membrane technology in the pulp and paper industry

2004 ◽  
Vol 50 (3) ◽  
pp. 217-227 ◽  
Author(s):  
J. Nuortila-Jokinen ◽  
M. Mänttäri ◽  
T. Huuhilo ◽  
M. Kallioinen ◽  
M. Nyström
Keyword(s):  
Membrane Fouling ◽  
Biological Treatment ◽  
Membrane Filtration ◽  
Paper Industry ◽  
Pulp And Paper Industry ◽  
Pulp And Paper ◽  
Paper Machine ◽  
Purification Method ◽  
High Molar Mass ◽  
Pre Treatment

In this study, membrane filtration as an internal purification method, “the kidney7rdquo;, in the pulp and paper industry is discussed. Membrane filtration is economically competitive and a very versatile process. It can be used to remove the enriched organic and/or inorganic loads either partially or totally from, for example, the mechanical pulping and paper making water circuits and it can be applied to various points within the process. With the so-called shear enhanced membrane modules very high fluxes, in ultrafiltration about 400 L/(m2h) and in nanofiltration fluxes almost 200 L/(m2h), have been obtained. Depending on the membrane, suspended solids (microfiltration), polysaccharides, extractives and high molar mass lignous substances (ultrafiltration) and multivalent salts (nanofiltration) can be removed. Ultrafiltration permeate can well be used in paper machine showers to replace fresh water. The quality of the nanofiltration permeate is significantly higher than that of ultrafiltration. The membrane processes can be enhanced by various pre-treatment techniques to produce higher permeate fluxes and to eliminate membrane fouling. Such pre-treatment methods are, e.g., chemical treatment, ozonation and biological treatment. The most cost-effective processes were chemical flocculation, pH adjustment and thermophilic aerobic biological treatment.

Burned wood in the pulp and paper industry: A literature review

2004 ◽  
Vol 80 (4) ◽  
pp. 473-477 ◽  
Author(s):  
Paul Watson ◽  
Simon Potter
Keyword(s):  
Moisture Content ◽  
Paper Industry ◽  
Pulp And Paper Industry ◽  
Pulp And Paper ◽  
Wood Chemistry ◽  
Mechanical Pulp ◽  
Kraft Cooking ◽  
Pre Treatment ◽  
One Year ◽  
Forest Architecture

Fires play an integral part in Canadian forest architecture. Low-value wood, from burned stems, is an important source of fibre for the pulp and paper industry. Although wood chemistry changes induced by fire are substantial, burned stems exhibit a demarcation layer between the char and undamaged wood which is only a few cells thick. The loss of stem moisture content requires that burned wood is processed within one year. Aggressive debarking will minimize charcoal contamination and careful metering of chips from burned wood into any pulping process is essential. Chips with low moisture content must be pre-steamed prior to kraft cooking, and chemical pre-treatment may improve mechanical pulp quality. Key words: burn intensity, wood chemistry, charring, stem moisture content, charcoal contamination, chip metering

Application of ultrafiltration in the pulp and paper industry: metals removal and whitewater reuse

2007 ◽  
Vol 55 (6) ◽  
pp. 117-123 ◽  
Author(s):  
C.R. Oliveira ◽  
C.M. Silva ◽  
A.F. Milanez
Keyword(s):  
Water Use ◽  
Paper Industry ◽  
Combined Treatment ◽  
Paper Mill ◽  
Pulp And Paper Industry ◽  
Pulp And Paper ◽  
Paper Machine ◽  
Paper Mills ◽  
Metals Removal ◽  
High Level

In the pulp and paper industry, the water use minimization is a constant target. One way to reduce water use is to recycle the effluent in a closed-cycle concept. In paper mills, the main source of liquid effluent is the so-called whitewater, which is the excess water, originated from pulp stock dewatering and other fibre contaminated water. This research studied the reuse of paper mill whitewater after membrane ultrafiltration (UF) in the paper machine and in the pulp bleach plant of an integrated mill. Contaminant removal and flux behaviour of the UF system were evaluated. The treatment by ultrafiltration was technically feasible and the treated whitewater had good potential to be reused in some processes in the paper machine. The reuse of ultrafiltered whitewater in the bleaching plant was not recommended because of the high level of soluble calcium present in this stream. Therefore, a combined treatment of the whitewater using the principle of precipitation and ultrafiltration was proposed showing good results and enabling the use of the treated whitewater in the bleach plant.

Ultra- and Nano-Filtration in Advanced Effluent Treatment Schemes for Pollution Control in the Pulp and Paper Industry

1992 ◽  
Vol 25 (10) ◽  
pp. 263-276 ◽  
Author(s):  
A. Zaidi ◽  
H. Buisson ◽  
S. Sourirajan ◽  
H. Wood
Keyword(s):  
Kraft Pulp ◽  
Paper Industry ◽  
Pulp And Paper Industry ◽  
Reduction Factor ◽  
Pulp And Paper ◽  
Effluent Treatment ◽  
High Shear ◽  
Permeate Flux ◽  
The Cost ◽  
Low Shear

The kraft pulp and paper industry is currently faced with the challenge of substantially reducing the discharge of conventional and toxic pollutants to the receiving environment without compromising its competitiveness. Ultrafiltration (UF) and nanofiltration (NF) are among the various unit processes that are being investigated by researchers interested in developing alternative schemes for meeting this challenge. The objectives of the work presented here were: (i) to review the potential uses for UF and NF in the kraft pulp and paper industry and (ii) to evaluate the performance of eleven UF and NF membranes using a caustic extraction stage effluent from a kraft mill pulping softwood with a O D55/C45 EO H D bleaching sequence. The experimental work was conducted with two flat-sheets bench-scale units fed in parallel: a low shear and a high shear unit. The most promising UF membrane gave an average permeate flux of 9 m3m2d for a volume reduction factor (VRF) of 30, under high-shear conditions at 0.69 MPa. The associated COD rejections ranged from 85%–90% at a VRF of 1 down to 70–75% at a VRF of 30. While the results demonstrated in this study show promise, further research is needed to demonstrate the cost effectiveness of both high-shear and low-shear equipment for this application as well as options for the reuse or treatment of the diluted and concentrated streams produced by the UF/NF systems.

Degradation of Recalcitrant Chlorinated Organics by Radiochemical and Biochemical Oxidation

1994 ◽  
Vol 29 (5-6) ◽  
pp. 219-228 ◽  
Author(s):  
D. Berge ◽  
H. Ratnaweera ◽  
H. Efraimsen
Keyword(s):  
Paper Industry ◽  
Pulp And Paper Industry ◽  
High Energy ◽  
Pulp And Paper ◽  
High Energy Electron ◽  
Practical Applications ◽  
Biochemical Oxidation ◽  
Pre Treatment ◽  
Aox Removal ◽  
Industry Wastewater

AOX removal from pulp and paper industry wastewater with traditional methods is still very difficult. A novel application, irradiation by high energy electron beam (EB), is investigated and 40% and 70% AOX removals were obtained by 10 kGy and 50 kGy dosages, respectively. Further removals are possible at higher dosages. Chemical pre-treatment had no significant effect on overall AOX removal by EB-treatment, while biological post-treatment removed AOX further. Practical applications at large pulp and paper plants are considered, and further research on the application of EB-treatment on concentrated effluents or sludges is recommended.

Co-cooking nonwoods with hardwoods

TAPPI Journal ◽  
2014 ◽  
Vol 13 (6) ◽  
pp. 19-24
Author(s):  
TROY RUNGE ◽  
CHUNHUI ZHANG
Keyword(s):  
High Performance Liquid Chromatography ◽  
High Performance ◽  
Paper Industry ◽  
Pulp And Paper Industry ◽  
Strength Properties ◽  
Agricultural Residues ◽  
Kraft Pulping ◽  
Pulp And Paper ◽  
Strength Increase ◽  
Xylan Content

Agricultural residues and energy crops are promising resources that can be utilized in the pulp and paper industry. This study examines the potential of co-cooking nonwood materials with hardwoods as means to incorporate nonwood material into a paper furnish. Specifically, miscanthus, switchgrass, and corn stover were substituted for poplar hardwood chips in the amounts of 10 wt %, 20 wt %, and 30 wt %, and the blends were subjected to kraft pulping experiments. The pulps were then bleached with an OD(EP)D sequence and then refined and formed into handsheets to characterize their physical properties. Surprisingly, all three co-cooked pulps showed improved strength properties (up to 35%). Sugar measurement of the pulps by high-performance liquid chromatography suggested that the strength increase correlated with enriched xylan content.

Application of VSEP for Pulp and Paper Industry.

1999 ◽  
Vol 53 (10) ◽  
pp. 1334-1338 ◽  
Author(s):  
Yoshiya Kuide ◽  
Kazuyoshi Yamamoto
Keyword(s):  
Paper Industry ◽  
Pulp And Paper Industry ◽  
Pulp And Paper
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