Bioplastics from activated sludge treating pulp and paper wastewater

The mutagenic properties of pulp and paper mill effluents were studied in three mills: bleached kraft mill with aerated lagoon treatment (Mill 1), bleached kraft mill with activated sludge treatment (Mill 2) and mechanical pulp/paper mill (Mill 3). Both treated and untreated effluents, process streams and molecular fractions were tested for mutagenicity (Ames test. Salmonella typhimurium TA100 and SCE sister chromatid exchange test, Chinese hamster ovary cells). To verify the potential environmental effects the mutagenic activity of concentrated recipient lake water (Mill 2) was also studied. The Ames mutagenicity of the bleached kraft mill effluent (BKME) originated from the first chlorination filtrate, SCE mutagenicity also occurred in the alkali extraction stage filtrate (Mill 1). No Ames mutagenicity was detected in the paper mill effluent, but it was SCE mutagenic. Activated sludge treatment of BKME removed both Ames and SCE mutagenicity, but the aerated lagoon treated BKME was still SCE mutagenic. No mutagenic activity was detected in the recipient water concentrates.

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Characterization of efficient xylanases from industrial-scale pulp and paper wastewater treatment microbiota

AMB Express ◽

10.1186/s13568-020-01178-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jia Wang ◽

Jiawei Liang ◽

Yonghong Li ◽

Lingmin Tian ◽

Yongjun Wei

Keyword(s):

Wastewater Treatment ◽

Xylanase Activity ◽

Pulp And Paper ◽

Optimal Conditions ◽

Paper Wastewater ◽

Termite Hindgut ◽

Uncultured Microorganisms ◽

Metagenomic Approach ◽

Gh10 Family

AbstractXylanases are widely used enzymes in the food, textile, and paper industries. Most efficient xylanases have been identified from lignocellulose-degrading microbiota, such as the microbiota of the cow rumen and the termite hindgut. Xylanase genes from efficient pulp and paper wastewater treatment (PPWT) microbiota have been previously recovered by metagenomics, assigning most of the xylanase genes to the GH10 family. In this study, a total of 40 GH10 family xylanase genes derived from a certain PPWT microbiota were cloned and expressed in Escherichia coli BL21 (DE3). Among these xylanase genes, 14 showed xylanase activity on beechwood substrate. Two of these, PW-xyl9 and PW-xyl37, showed high activities, and were purified to evaluate their xylanase properties. Values of optimal pH and temperature for PW-xyl9 were pH 7 and 60 ℃, respectively, while those for PW-xyl37 were pH 7 and 55 ℃, respectively; their specific xylanase activities under optimal conditions were 470.1 U/mg protein and 113.7 U/mg protein, respectively. Furthermore, the Km values of PW-xyl9 and PW-xyl37 were determined as 8.02 and 18.8 g/L, respectively. The characterization of these two xylanases paves the way for potential application in future pulp and paper production and other industries, indicating that PPWT microbiota has been an undiscovered reservoir of efficient lignocellulase genes. This study demonstrates that a metagenomic approach has the potential to screen efficient xylanases of uncultured microorganisms from lignocellulose-degrading microbiota. In a similar way, other efficient lignocellulase genes might be identified from PPWT treatment microbiota in the future.

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AOX removal from pulp and paper wastewater by Fenton and photo-Fenton processes: A real case-study

Energy Reports ◽

10.1016/j.egyr.2019.09.068 ◽

2020 ◽

Vol 6 ◽

pp. 770-775 ◽

Cited By ~ 3

Author(s):

J.P. Ribeiro ◽

C.C. Marques ◽

I. Portugal ◽

M.I. Nunes

Keyword(s):

Pulp And Paper ◽

Real Case ◽

Paper Wastewater ◽

Aox Removal

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Controlling the Settling of Activated Sludge in Pulp and Paper Wastewater Treatment Plants

Water Science & Technology ◽

10.2166/wst.1999.0716 ◽

1999 ◽

Vol 40 (11-12) ◽

pp. 223-229 ◽

Cited By ~ 8

Author(s):

Frédéric Clauss ◽

Christel Balavoine ◽

Delphine Hélaine ◽

Gaëtan Martin

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Wastewater Treatment Plants ◽

Pulp And Paper ◽

Organic Load ◽

Forest Industry ◽

Filamentous Bulking ◽

Mineral Particles ◽

Mineral Powder

Forest industry wastewaters are difficult to clean: hydraulic and organic load variations, filamentous bulking or pin-point flocs negatively impact depollution processes. The addition of a fine, mineral, talc-based powder, Aquatal, into the aeration tanks of wastewater treatment plants connected to pulp and paper factories has been successfully tested since end of '97. The first case-study presents full results obtained over a period of 18 months in a 20,000 p.e. plant connected to a paper factory. The mineral powder was regularly added to control sludge volume index, thereby ensuring low suspended solids concentration in the outfluent. Plant operators could easily adapt biomass concentration to match organic load variation, thereby maintaining pollution micro-organisms ratio constant. In a second case study, a trouble-shooting strategy was implemented to counteract filamentous bulking. A one-off, large dosage enabled the plant operator to deal effectively with poor settleability sludge and rapidly control sludge blanket expansion. In both cases, the main common characteristics observed were an increase in floc aggregation and the production of heavier and well-structured flocs. The sludge settling velocity increased and an efficient solid/liquid separation was obtained. After a few days, the mineral particles of Aquatal were progressively integrated into the sludge floc structure. When the mineral powder was added to the activated sludge in the aeration basin, chemical interactions frequently encountered with other wastewater treatment additives did not pose a problem. Moreover, with this mineral additive, the biological excess sludge displayed good thickening properties and dewatering was improved. Despite the addition of the insoluble mineral particles, the amount of wet sludge expelled did not increase. Aquatal offers a rapid solution to floc settleability problems which so frequently arise when physical or biological disorders appear in forest industry wastewater treatment plants.

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