An examination of the surface characteristics of activated sludge in relation to bulking during the treatment of paper mill wastewater

We examined the microbial community structure and quantified the levels of the filamentous bulking organism Thiothrix eikelboomii in samples of activated sludge mixed liquor suspended solids (MLSS) from Canadian pulp and paper mills. Libraries of chaperonin 60 (cpn60) gene sequences were prepared from MLSS total microbial community DNA and each was compared with cpnDB, a reference database of cpn60 sequences (http://cpndb.cbr.nrc.ca) for assignment of taxonomic identities. Sequences similar to but distinct from the type strain of T. eikelboomii AP3 (ATCC 49788T) (~89% identity over 555 bp) were recovered at high frequency from a mill sample that was experiencing bulking problems at the time of sample collection, which corresponded to microscopic observations using fluorescent in situ hybridization with commercially available 16S rDNA-based probes. We enumerated this strain in five mill-derived MLSS samples using real-time quantitative PCR (qPCR) and found that two samples had high levels of the bulking strain (>1012genomes/g MLSS) and two contained lower but detectable levels of this organism. None of the mill samples contained cpn60 sequences that were identical to the type strain of T. eikelboomii. This technique shows promise for monitoring pulp and paper mill wastewater treatment systems by detecting and enumerating this strain of T. eikelboomii, which may be specific to pulp and paper mill wastewater treatment systems.Key words: activated sludge, biological treatment, bulking; chaperonin 60, cpn60, filamentous bacteria, mixed liquor suspended solids, microbial communities, 021N, qPCR, settling, Thiothrix.

Download Full-text

Comparative study of MBR and activated sludge in the treatment of paper mill wastewater

Water Science & Technology ◽

10.2166/wst.2007.208 ◽

2007 ◽

Vol 55 (6) ◽

pp. 23-29 ◽

Cited By ~ 22

Author(s):

M. Lerner ◽

N. Stahl ◽

N.I. Galil

Keyword(s):

Activated Sludge ◽

Membrane Bioreactor ◽

Suspended Solids ◽

Paper Mill ◽

Ammonia Nitrogen ◽

Quality Parameters ◽

Maintenance Cost ◽

Effluent Quality ◽

Monitoring Time ◽

Paper Mill Wastewater

The study was based on a full scale activated sludge plant (AS) compared to a parallel operated pilot membrane bioreactor (MBR) with flat sheets membranes. Both systems received their influent from an anaerobic bioreactor treating paper mill wastewater. MBR produced an effluent of much better quality than AS in terms of suspended solids, containing 1 mg/L or less in 80% of the monitoring time, while the AS effluent contained 12 mg/L. This could save the necessity of further treatment by filtration in the case of MBR. Other effluent quality parameters, such as organic matter (COD and BOD), phosphorus and ammonia nitrogen, did not indicate substantial differences between AS and MBR. Calcium carbonate scaling and formation of a bacterial layer on the membrane caused severe flux reduction. The membrane blockage because of scaling and biofouling proved to be very serious, therefore, it required proper and more complicated maintenance than the AS system. This study leads to the conclusion that in the case of paper mill wastewater, after anaerobic biotreatment, if there is no need for excellent effluent quality in terms of suspended solids, the replacement of the AS by the MBR would not be strongly justified, mainly because of maintenance cost.

Download Full-text

Production of polyhydroxyalkanoates by activated sludge treating a paper mill wastewater

Bioresource Technology ◽

10.1016/j.biortech.2007.01.020 ◽

2008 ◽

Vol 99 (3) ◽

pp. 509-516 ◽

Cited By ~ 212

Author(s):

Simon Bengtsson ◽

Alan Werker ◽

Magnus Christensson ◽

Thomas Welander

Keyword(s):

Activated Sludge ◽

Paper Mill ◽

Paper Mill Wastewater

Download Full-text

Mutagenicity in Pulp and Paper Mill Effluents and in Recipient

Water Science & Technology ◽

10.2166/wst.1988.0054 ◽

1988 ◽

Vol 20 (2) ◽

pp. 143-152 ◽

Cited By ~ 4

Author(s):

A. Langi ◽

M. Priha

Keyword(s):

Activated Sludge ◽

Mutagenic Activity ◽

Chinese Hamster Ovary Cells ◽

Chinese Hamster ◽

Paper Mill ◽

Pulp And Paper ◽

Pulp And Paper Mill ◽

Sludge Treatment ◽

Paper Mill Effluents ◽

Kraft Mill

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.

Download Full-text

Chemical characterization and biotreatability of effluents from an integrated alkaline-peroxide mechanical pulping/machine finish coated (APMP/MFC) paper mill

Water Science & Technology ◽

10.2166/wst.1997.0470 ◽

1997 ◽

Vol 35 (2-3) ◽

pp. 7-14 ◽

Cited By ~ 3

Author(s):

A. Schnell ◽

M. J. Sabourin ◽

S. Skog ◽

M. Garvie

Keyword(s):

Activated Sludge ◽

Aquatic Toxicity ◽

Wood Chip ◽

Chemical Characterization ◽

Toxicity Testing ◽

Sampling Period ◽

Paper Mill ◽

Alkaline Peroxide ◽

Conventional Activated Sludge ◽

Treated Effluent

As part of an extensive audit of the Alkaline-Peroxide Mechanical Pulping (APMPTM) plant at the Malette Quebec Inc. mill in St. Raymond, Que., effluents were sampled from various stages of the process for comprehensive chemical characterizations, aquatic toxicity testing and anaerobic biotreatability assessments. In addition, untreated and secondary treated combined effluent from the integrated paper mill were sampled to determine the effectiveness of a conventional activated sludge process at the mill site. During the one-day sampling period, the APMP plant processed a mixed wood furnish consisting of 50% spruce/balsam fir and 50% aspen, with a chemical charge of 3.5% sodium hydroxide and 3.8% hydrogen peroxide on oven-dry fibre, while the Machine Finish Coated (MFC) paper production rate was 100 odt/d (oven dry metric tonnes per day). Measured production-specific contaminant discharge loadings from the novel APMP process were 56 kg BOD5/odt and 155 kg COD/odt in a combined effluent flow of 28 m3/odt. Sources of process effluent were chip washing, three stages of wood chip pretreatment and chemical impregnation (i.e., Impressafiner stages), interstate washing and pulp cleaning. The three Impressafiner pressates were found to be the most concentrated (i.e., 12-26 g COD/L) and toxic streams. Microtox testing of the pressates revealed EC50 concentrations of 0.07-0.34% v/v. The warm and concentrated effluents generated by the non-sulphur APMP process were found to be highly amenable to anaerobic degradation as determined by batch bioassay testing. Filterable BOD5 and COD(f) of the process effluents were reduced by 87-95% and 70-77%, respectively, with corresponding theoretical methane yields being attained. Acid-soluble dissolved lignin compounds exhibited biorecalcitrance, as revealed by limited removals of 34-55%, and were the main constituents contributing to residual COD(f), while resin and fatty acids (RFA) were reduced by 80-94%. The conservatively operated full scale activated sludge treatment process achieved a similar high 74% COD(f) removal from the whole mill effluent, while BOD5 and RFA reductions were virtually complete and the treated effluent was non-toxic, as measured by Microtox.

Download Full-text