The formation of colour during biological treatment of pulp and paper wastewater

2004 ◽  
Vol 50 (3) ◽  
pp. 87-94 ◽  
Author(s):  
C.B. Milestone ◽  
R.R. Fulthorpe ◽  
T.R. Stuthridge
Keyword(s):  
Activated Sludge ◽  
Paper Industry ◽  
Paper Mill ◽  
Anaerobic Treatment ◽  
Subsequent Treatment ◽  
Pulp And Paper ◽  
Effluent Treatment ◽  
Pulp And Paper Mill ◽  
Anaerobic Conditions ◽  
Significant Change

Colour discharges are gaining renewed focus in the pulp and paper industry as increasingly strict regulatory limits are placed on wastewater quality and aesthetics. In-mill process improvements, such as ECF bleaching and oxygen delignification, have decreased wastewater colour loadings. However, a survey of 12 pulp and paper mill systems found that effluent treatment using aerated stabilisation basins (ASB) leads to average increases in colour of 20-40%. In some instances, this phenomenon may even double the influent colour levels. Activated sludge systems did not produce a colour increase. The measured increases that follow ASB secondary treatment may be sufficient for a mill to fail prescribed discharge standards. A detailed field survey focusing on sections of an integrated bleached kraft mill ASB treatment system was undertaken. The average increase in colour at the final point of discharge was 45%. The major changes in colour concentration occurred in the inlet to the main treatment pond, and in polishing ponds that followed the main treatment pond. Both of these areas receive little or no aeration. No significant change was observed in the highly aerated main pond. These results, along with literature reports, suggested that redox conditions play a major role in influencing colour behaviour. To test this, two series of paired continuously stirred reactors were used to treat whole mill effluent from two ECF bleached kraft mills in parallel. The first series initially treated under anaerobic conditions, followed by an aerobic reactor, while the second series reversed this order. With the initial anaerobic stage, effluent colour increased by 18% and 19% for the first and second series respectively. Subsequent treatment by aerobic bacteria further increased colour by 14% and 6%, for a total increase of 32% and 25%. Initial aerobic treatment, however, did not lead to any significant change in colour for either effluent. Further anaerobic treatment following aerobic conditions produced only small increases in colour. These results are consistent with the ASB and activated sludge system survey, suggesting that anaerobic conditions at the head of treatment systems initiate the observed increases in effluent colour in ASB treatment systems.

Clarifier Performance in Activated Sludge Process Treating Pulp and Paper Mill Effluents

1994 ◽  
Vol 29 (5-6) ◽  
pp. 313-328 ◽  
Author(s):  
Sakari Halttunen
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Paper Industry ◽  
Paper Mill ◽  
Field Studies ◽  
Pulp And Paper ◽  
Pulp And Paper Mill ◽  
Paper Mill Effluents ◽  
Sludge Settling ◽  
Activated Sludge Processes

High suspended solids concentrations are typical for pulp and paper industry treated effluents. A new clarifier model was developed to find the reasons for this problem. The model clarifier is divided into four different zones: inlet, settling, thickening and separation. In the inlet zone sludge is transported by water flow and neither thickening nor settling will happen. When water velocity decreases the main part of the sludge will settle until it reaches the thickening zone. Thickening will continue until the sludge is pumped away from the clarifier. Concentration increase depends on sludge concentration, time and specific thickening coefficient. The minor part, which is specific to the sludge, enters the separation zone and will either settle in the thickening zone or stay in the effluent. In intensive field studies on 12 different activated sludge processes sludge volume in the clarifier, effluent suspended solids concentrations and sludge settling qualities were examined. Modelled sludge blanket volumes were verified with blanket measurements. Modelled effluent suspended solids were also verified by concentration measurements. Sludge thickening characteristics can be estimated by DSVI. From the data collected two empirical relationships were noticed between sludge settling properties and process operation. Solids concentration in clarified water depends on settling number, which is the mean number of sludge settling during its residence time in the process (sludge age). Sludge settling properties seem to depend on collision load, which is defined as COD-load divided by return sludge biomass flow.

Anaerobic treatment of pulp and paper mill effluents – status quo and new developments

2007 ◽  
Vol 55 (6) ◽  
pp. 223-230 ◽  
Author(s):  
Leo Habets ◽  
Willie Driessen
Keyword(s):  
Paper Industry ◽  
Industrial Effluents ◽  
Paper Mill ◽  
Anaerobic Treatment ◽  
Pulp And Paper ◽  
Pulp And Paper Mill ◽  
Widespread Application ◽  
Paper Mills ◽  
Paper Mill Effluents ◽  
Pre Treatment

Since the early 1980s, anaerobic treatment of industrial effluents has found widespread application in the pulp and paper industry. Over 200 installations are treating a large variety of different pulp and paper mill effluents. Amongst various anaerobic systems the UASB and IC are the most applied anaerobic reactor systems. Anaerobic treatment is well feasible for effluents originated from recycle paper mills, mechanical pulping (peroxide bleached), semi-chemical pulping and sulphite and kraft evaporator condensates. The advantages of anaerobic pre-treatment are (1) net production of renewable energy (biogas), (2) minimized bio-solids production, (3) minimal footprint and (4) reduced emission of greenhouse gases. Via in-line application of anaerobic treatment in closed circuits (paper kidney technology) further savings on cost of fresh water intake and effluent discharge levies are generated.

Effect of ozonation on activated sludge from pulp and paper industry

2010 ◽  
Vol 62 (7) ◽  
pp. 1676-1681 ◽  
Author(s):  
S. Gupta ◽  
S. K. Chakrabarti ◽  
S. Singh
Keyword(s):  
Activated Sludge ◽  
Paper Industry ◽  
Bacterial Biomass ◽  
Cost Effective ◽  
Paper Mill ◽  
Pulp And Paper Industry ◽  
Pulp And Paper ◽  
Pulp And Paper Mill ◽  
Secondary Sludge ◽  
Predominant Process

Aerobic biological treatment with activated sludge is the predominant process all over the world for treatment of pulp and paper industry wastewater. 50–70% of the biodegradable organic material is oxidized to CO2 and the rest is converted to bacterial biomass, typically termed as excess sludge or waste activated sludge (WAS). Handling and disposal of WAS in general and in particular from the pulp and paper industry face different processing difficulties, regulatory stringency due to organochlorine contamination and reluctance of people for reuse. With an objective of reducing the net disposable biomass, ozonation of WAS from a pulp and paper mill and from a laboratory scale batch activated sludge process operated with the wastewater and bacterial seed of the same pulp and paper mill have been carried out. With the mill sludge having predominant filamentous organisms 18% MLSS was reduced at an ozone dosage of 55 mg O3/g dry MLSS solid (DS) resulting in 2.5 times COD increase. With the laboratory sludge which is well structured and flocculating, only 6% MLSS was reduced at an ozone dosage of 55 mg O3/g DS. Ozonation mineralizes 26% and 20% AOX compounds embedded in the secondary sludge in the mill and laboratory sludge respectively at an ozone dosage of 55 mg O3/g DS. During ozonation, absorbed/adsorbed lignin on biomass was released which resulted in increased colour concentration. Ozonation can be a potential oxidative pretreatment process for reducing the WAS and paving the way for cost effective overall treatment of WAS.

Pilot-scale comparison of thermophilic aerobic suspended carrier biofilm process and activated sludge process in pulp and paper mill effluent treatment

2004 ◽  
Vol 50 (3) ◽  
pp. 95-102 ◽  
Author(s):  
J.E. Suvilampi ◽  
J.A. Rintala
Keyword(s):  
Activated Sludge ◽  
Paper Mill ◽  
Pilot Scale ◽  
Pulp And Paper ◽  
Effluent Treatment ◽  
Activated Sludge Process ◽  
Pulp And Paper Mill ◽  
Paper Mill Effluent ◽  
Biofilm Process ◽  
Suspended Carrier

Thermophilic aerobic treatment of settled pulp and paper mill effluent was studied under mill premises with two comparative pilot processes; suspended carrier biofilm process (SCBP) and activated sludge process (ASP). Full-scale mesophilic activated sludge process was a reference treatment. During the runs (61 days) hydraulic retention times (HRTs) were kept 13 ± 5 h and 16 ± 6 h for SCBP and ASP, respectively. Corresponding volumetric loadings rates (VLR) were 2.7 ± 0.9 and 2.2 ± 1.0 kg CODfilt m-3d-1. Temperatures varied between 46 to 60°C in both processes. Mesophilic ASP was operated with HRT of 36 h, corresponding VLR of 0.7 kg CODfilt m-3d-1. Both SCBP and ASP achieved CODfilt (GF/A filtered) removals up to 85%, while the mesophilic ASP removal was 89 ± 2%. NTU values were markedly higher (100-300) in thermophilic effluents than in mesophilic effluent (30). Effluent turbidity was highly dependent on temperature; in batch experiment mesophilic effluent sample had NTU values of 30 and 60 at 35°C and 55°C, respectively. As a conclusion, both thermophilic treatments gave high CODfilt removals, which were close to mesophilic process removal and were achieved with less than half of HRT.

scholarly journals Coliform Bacteria and Nitrogen Fixation in Pulp and Paper Mill Effluent Treatment Systems

2000 ◽  
Vol 66 (12) ◽  
pp. 5155-5160 ◽  
Author(s):  
Francis Gauthier ◽  
Josh D. Neufeld ◽  
Brian T. Driscoll ◽  
Frederick S. Archibald
Keyword(s):  
Activated Sludge ◽  
Water System ◽  
Paper Mill ◽  
Pulp And Paper ◽  
Effluent Treatment ◽  
Coliform Bacteria ◽  
Pulp And Paper Mill ◽  
Paper Mills ◽  
Paper Mill Effluent ◽  
Contrast Analysis

ABSTRACT The majority of pulp and paper mills now biotreat their combined effluents using activated sludge. On the assumption that their wood-based effluents have negligible fixed N, and that activated-sludge microorganisms will not fix significant N, these mills routinely spend large amounts adding ammonia or urea to their aeration tanks (bioreactors) to permit normal biomass growth. N2 fixation in seven Eastern Canadian pulp and paper mill effluent treatment systems was analyzed using acetylene reduction assays, quantitative nitrogenase (nifH) gene probing, and bacterial isolations. In situ N2 fixation was undetectable in all seven bioreactors but was present in six associated primary clarifiers. One primary clarifier was studied in greater detail. Approximately 50% of all culturable cells in the clarifier contained nifH, of which >90% were Klebsiella strains. All primary-clarifier coliform bacteria growing on MacConkey agar were identified as klebsiellas, and all those probed contained nifH. In contrast, analysis of 48 random coliform isolates from other mill water system locations showed that only 24 (50%) possessed thenifH gene, and only 13 (27%) showed inducible N2-fixing activity. Thus, all the pulp and paper mill primary clarifiers tested appeared to be sites of active N2fixation (0.87 to 4.90 mg of N liter−1 day−1) and a microbial community strongly biased toward this activity. This may also explain why coliform bacteria, especially klebsiellas, are indigenous in pulp and paper mill water systems.

scholarly journals Radiotracer investigation of a pulp and paper mill effluent treatment plant

Nukleonika ◽  
2017 ◽  
Vol 62 (4) ◽  
pp. 289-294 ◽  
Author(s):  
Metali Sarkar ◽  
Vikas K. Sangal ◽  
Haripada Bhunia ◽  
Pramod K. Bajpai ◽  
Harish J. Pant ◽  
...  
Keyword(s):  
Paper Industry ◽  
Treatment Plant ◽  
Paper Mill ◽  
Pulp And Paper ◽  
Effluent Treatment ◽  
Aeration Tank ◽  
Pulp And Paper Mill ◽  
Dead Zones ◽  
Effluent Treatment Plant ◽  
Secondary Clarifier

Abstract The pulp and paper industry is highly dependent on water for most of its processes, producing a significant amount of wastewater that should be treated to comply with environmental standards before its discharge into surface-water reservoirs. The wastewater generated primarily consists of substantial amounts of organic, inorganic, toxic and pathogenic compounds in addition to nutrients, which are treated in an effluent treatment plant that often combines primary, secondary, tertiary and advanced treatments. However, the treatment methods vary from industry to industry according to the process utilized. The effective performance of effluent treatment plants is crucial from both environmental and economic points of view. Radiotracer techniques can be effectively used to optimize performance and detect anomalies like dead zones, bypassing, channelling, etc. in wastewater treatment plants. Experiments on the distribution of residence time were performed on the aeration tank and secondary clarifier of a full-scale pulp and paper mill to study the flow behaviour as well as locate system anomalies and hence evaluate the performance of the treatment plants using the radiotracer I-131. The convolution method was applied to model the system with an imperfect impulse radiotracer input. The aeration tank was working efficiently in the absence of any dead zones or bypassing. Various hydrodynamic models available in the literature were applied on the aeration tank and secondary clarifier to obtain the hydraulic representation of the systems.

Mutagenicity in Pulp and Paper Mill Effluents and in Recipient

1988 ◽  
Vol 20 (2) ◽  
pp. 143-152 ◽  
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.

Applying phenotypic fingerprinting in the management of wastewater treatment systems

1998 ◽  
Vol 37 (4-5) ◽  
pp. 461-464 ◽  
Author(s):  
C. A. Schneider ◽  
K. Mo ◽  
S. N. Liss
Keyword(s):  
Paper Mill ◽  
Substrate Utilization ◽  
Pulp And Paper ◽  
Effluent Treatment ◽  
Management Tool ◽  
Carbon Substrate ◽  
Pulp And Paper Mill ◽  
Fame Analysis ◽  
Pulp And Paper Effluent ◽  
Biolog Gn

Carbon substrate utilization profiles, phenotypic fingerprints, of microbial communities from different pulp and paper effluent treatment systems are being determined using Biolog plates. The substrates from the Biolog GN plates that were deemed to be most significant in differentiating between communities are being employed as substrate panels on Biolog MT plates. Correlative microbiological tests including FAME analysis, heterotrophic plate counts, and epifluorescent microscopy are performed on the samples. By correlating the phenotypic fingerprints to pulp and paper mill processes and operation parameters in the treatment systems, the carbon substrate utilization profile has shown potential as a useful management tool.

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