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Nothrop S.,Norske Skog Technical Support and Development | Nothrop S.,University of South Australia | Richardson D.,Norske Skog Technical Support and Development | Van Leeuwen J.,University of South Australia | And 4 more authors.
Appita Annual Conference | Year: 2013

In this study, we showed that bulking of an activated sludge plant treating newsprint mill wastewater was due to Zoogloeal viscous bulking (or hydrous bulking); a condition that can occur when there are high concentrations of readily degradable organics (e.g. resin acids, fatty acids and soluble carbohydrates) and/or low macro-nutrients (N&P) and/or lengthy anoxic conditions preceding aeration. At Norske Skog's Albury Activated Sludge Plant (ASP) Zoogloeal viscous bulking appeared as microscopic amorphous clumps and formed a crust on wastewater during secondary clarification together with significant foaming in aeration tanks. Production of foaming polysaccharides/exopolymeric substance (EPS) was confirmed using Methylene Blue stain; dispersed and light blue floc characteristics were observed. This condition resulted in the production of white billowy foam, which adversely impacted on the settleability and dewaterability of ASP sludge. Zoogloeal viscous bulking can be controlled by reducing the Food: Micro-organism (F: M) ratio, maintaining suitable macro-nutrient (orthophosphate and ammonium; P&N) residuals, limiting growth rates with an anoxic selector after an aerobic selector and/or reducing anoxic conditions preceding an aerobic selector. At the ASP a COD F: M ratio of 20 into selector one resulted in significant Zoogloeal bulking. Controlling Zoogloeal growth rates with an anoxic selector two and maintaining suitable ammonium and orthophosphate levels in both aeration tanks was successful in controlling EPS production. Firm floc characteristics (dark blue and low in polysaccharide) were observed using Methylene Blue staining. Defoamer requirements were reduced by a factor of ten.


Nothrop S.,Norske Skog Technical Support and Development | Nothrop S.,University of South Australia | Richardson D.,Norske Skog Technical Support and Development | Van Leeuwen J.,University of South Australia | And 4 more authors.
Appita Journal | Year: 2014

In this study, we showed that bulking in an activated sludge plant treating newsprint mill wastewater was due to Zoogloeal viscous bulking (or hydrous bulking). At Norske Skog’s Albury activated sludge plant (ASP) Zoogloeal viscous bulking appeared as microscopic amorphous clumps and formed a crust on wastewater during secondary clarification together with significant foaming in aeration tanks. Production of foaming polysaccharides/exopolymeric substance (EPS) was confirmed using Methylene Blue stain, whereby dispersed and light blue floe characteristics were observed. The condition resulted in the production of white billowy foam, which adversely impacted on the settleability and dewaterabitity of ASP sludge. Zoogloeal viscous bulking can be controlled by reducing the Food/Micro-organism (F/M) ratio, maintaining suitable macro-nutrient (orthophosphate and ammonium; P&N) residuals, limiting growth rates with an anoxic selector after an aerobic selector and/or reducing anoxic conditions preceding an aerobic selector. At the ASP a COD F/M ratio of 20:1 into Selector 1 resulted in significant Zoogloeal bulking. Controlling Zoogloeal growth rates with an anoxic Selector 2 and maintaining suitable ammonium and orthophosphate levels in both aeration tanks was successful in controlling EPS production. Firm floe characteristics (dark blue and low in polysaccharide) were observed using Methylene Blue staining. Defoamer requirements were reduced by a factor of ten. © 2014, Appita Inc. All rights reserved.


Lestiani R.,Monash University | Batchelor W.,Monash University | Banham P.,Norske Skog Technical Support and Development
BioResources | Year: 2015

Linting occurs when small particles are removed from the paper surface by the splitting of the tacky ink film. Excessive linting reduces printing quality and can affect the pressroom efficiency. An improved method, using video camera technology, has been utilized to measure the dynamics of linting during the printing process. This technology makes it feasible to estimate the removal of lint particles from the paper and from the blanket surfaces. This article presents the latest development of the lint camera system and its applications under different press conditions, including ink color. The lint measurements obtained by the camera system were compared with the established measurement methods (blanket tape pull and blanket wash). The main result from this study indicates some similarities in the lint area distribution measured by the camera system and the blanket tape pull. The differences in the lint area distribution from the filtered sample at small particle sizes is likely due to disaggregation of the agglomerated lint particles during the washing and filtering, and as a result, of more small particles being measured from the tape pulls.


Lestiani R.,Monash University | Batchelor W.,Monash University | Banham P.,Norske Skog Technical Support and Development
Appita Journal | Year: 2013

Linting is the removal of materials from the surface of uncoated paper during offset printing, and is a particular issue with sheets made from mechanically pulped fibres. Linting is a complex problem because it is a dynamic process that is influenced by both the printing press and the paper. In 2006, a video camera combined with image analysis was introduced to measure lint build-up on a blanket during printing and to separate the effect of the press variables from the effect of the paper. This paper reviews subsequent improvements that have been made to the system, and examines the suitability of the system to conduct research into the dynamics of lint or for routine quality control measurements. To do this, the lint particles identified by the camera, will be compared to the lint obtained by washing the blanket. The area distributions of lint measured when the press was running (dynamic), and halted (static) were compared to the lint measured from the washed and filtered samples. The dynamic images show a larger area on the blanket being detected as lint compared with the other two measurement methods. The dynamic images also significantly overestimated the area of large particles. The differences in the lint area distribution suggest that the dynamic measurements need to be improved further before they can be reliably used for the analysis of linting dynamics. The area of the lint removed in the static images was promising as it shows rather similar results to the lint removed by washing the blanket, suggesting that the camera is a suitable replacement for time-consuming measurements of lint by washing and image analysis.


Lestiani R.,Monash University | Batchelor W.,Monash University | Banham P.,Norske Skog Technical Support and Development
Journal of Adhesion Science and Technology | Year: 2014

Lint problems occur when loosely bonded particles detach from the surface of uncoated paper and accumulate on the printing blanket. We investigated the effect of paper and the printing press variables of printing tone and ink tack on linting using a lint camera system and also by stopping the press repeatedly to wash the lint samples off the blanket. Lint particles were classified into small particles (with area 0-8000 μm2) and large particles (with area above 8000 μm2). There have been many contradictory reports about the most important paper and printing variables affecting linting because many previous researchers have not adequately addressed that linting is a dynamic process, which involves two adhesion failures and separations, driven by the splitting of the viscous ink film. The first failure is for the removal of lint particles from the paper surface to the blanket, while the second failure is for the separation of the lint particles from the blanket. The key finding of this study is that these two rates of adhesion failure are generally correlated. That is, a higher rate of lint particle separation from the paper surface is associated with a higher rate of separation from the blanket. This finding held for varying the grade of paper, the ink viscosity and the printing tone, and for small and large particles. Previous contradictory results from linting studies are because lint has only been measured after completing a printing trial, with no means of examining the two underlying adhesion failure processes. © 2014 Taylor & Francis.


Richardson D.,Norske Skog Technical Support and Development | Murray B.,Orica Watercare | Blom L.,Norske Skog FOCUS
Appita Annual Conference | Year: 2010

Pilot scale experiments using the MIEX® process were conducted on biologically treated pulp and paper mill effluent from Norske Skog's Albury mill. The results of the pilot plant trial indicated that the treated water quality targets for both dissolved COD (120 mg L-1) and Colour (80 Hazen units (HU)) could be consistently achieved when using the following operating conditions: • Treatment rate of 250 bed volume (BV); • Counter current plant configuration; • Periodic high pH regeneration (i.e. 2 high pH regenerations/week); • Monthly plant disinfection using sodium hypochlorite. Analysis of the results achieved suggests that a treatment rate of 500BV combined with periodic high pH regeneration may be successful at achieving the dissolved COD treated water target. Using the treatment rate of 500BV would result in significant reductions of both capital and operating costs for a full scale installation, as well as minimising any increase in conductivity.

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