Correlation of wood-based components and dewatering properties of waste activated sludge from pulp and paper industry

2010 ◽  
Vol 62 (2) ◽  
pp. 387-393 ◽  
Author(s):  
H. Kyllönen ◽  
J. Lehto ◽  
P. Pirkonen ◽  
A. Grönroos ◽  
H. Pakkanen ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Paper Industry ◽  
Bound Water ◽  
Calorific Value ◽  
Pulp And Paper Industry ◽  
Pulp And Paper ◽  
Waste Activated Sludge ◽  
Paper Mills ◽  
Elementary Analysis ◽  
Solids Content

Large amounts of wet sludge are produced annually in municipal and industrial wastewater treatment. Already in pulp and paper industry, more than ten million tons of primary sludge, waste activated sludge, and de-inking sludge is generated. Waste activated sludge contains large quantities of bound water, which is difficult to dewater. Low water content would be a matter of high calorific value in incineration but it also has effects on the volume and the quality of the matter to be handled in sludge disposal. In this research waste activated sludges from different pulp and paper mills were chemically characterised and dewatered. Correlations of chemical composition and dewatering properties were determined using multivariate analysis. Chemical characterisation included basic sludge analysis, elementary analysis and analysis of wood-based components, such as hemicelluloses and lignin-derived material. Dewatering properties were determined using measurements of dry solids content, flux and flocculant dosage. The effects of different variables varied according to the response concerned. The variables which were significant regarding cake DS increase in filtration or centrifugation and flocculant dosage needed in filtration were different from those which were significant regarding flux.

The Development of Waste Water Treatment in the Finnish Pulp and Paper Industry

1988 ◽  
Vol 20 (1) ◽  
pp. 25-36 ◽  
Author(s):  
A. Luonsi ◽  
J. Junna ◽  
I. Nevalainen
Keyword(s):  
Activated Sludge ◽  
Pollution Control ◽  
Biological Treatment ◽  
Paper Industry ◽  
Waste Water Treatment ◽  
Treatment Plant ◽  
Quality Criteria ◽  
Pulp And Paper Industry ◽  
Pulp And Paper ◽  
Target Values

The recent development of Finnish pulp and paper industry external wastewater treatment has created positive results by reducing the oxygen consuming load (BOD7) of the recipients. This is due to the thirteen activated sludge plants and one anaerobic reactor which have been constructed during the last four years. The target values set in the form of suspended solids (SS) and BOD7 for 1985 (400 t BOD7/d) are expected to be achieved during 1987. Activated sludge plants have also created negative effects in the form of large amounts of surplus biological sludge and increased nutrient discharges, especially phosphorus which with reduced acute toxicity will increase the eutrophication of discharge areas. The share of activated sludge plants for the increased phosphorus discharges remains to be studied. The rapid increase started before the activated sludge plants started operation. In well operated activated sludge plant nutrient discharge is not increased. Although the specific water consumption and specific organic loads continuously decrease in pulp and paper production the increased production and more stringent requirements for pollution control prerequisite investments for external treatment. Therefore it is the time for efficient biological treatment plant construction and before 1995 a good number of mainly activated sludge plants will be constructed, for which time target values and some alternative guidelines to pollution control have been planned but not yet officially issued. Also requirements for CODCr, and total organic chlorine (TOCl) will be among the effluent quality criteria in the near future. When further requirements are issued the basis must be in the requirements of the biota which it is desired to live in the discharge areas. Much research is needed to find out how many of these requirements can be satisfied by modifications of present treatment processes. Thereafter the possibility of removing specific pollutants from the low volume fractions must be identified. The results of these studies must then be compared with the tertiary processes which can be added after the biological treatment plants which process the combined mill effluent. The problem must be regarded as a complex one because any substance removed from the wastewater will be found either in the sludge or in the air. The harmful compounds should be returned to normal ecological circulation or to the least harmful form and location in the most suitable waste stream.

Energy efficient aeration of wastewaters from the pulp and paper industry

2010 ◽  
Vol 62 (10) ◽  
pp. 2364-2371 ◽  
Author(s):  
M. Sandberg
Keyword(s):  
Oxygen Transfer ◽  
Biological Treatment ◽  
Bubble Column ◽  
Paper Industry ◽  
Electrical Power ◽  
Treatment Plant ◽  
Pulp Mill ◽  
Pulp And Paper Industry ◽  
Pulp And Paper ◽  
Paper Mills

More than 50% of the electrical power needed to treat pulp and paper industry effluents is used for aeration in biological treatment stages. A large share of the oxygen that passes through the wastewater is not consumed and will be found in the off-gas. Energy can be saved by aerating under conditions where the oxygen transfer is most efficient, for example at low concentrations of dissolved oxygen Consider the sludge as an energy source; electricity can be saved by avoiding sludge reduction through prolonged aeration. High oxygen transfer efficiency can be retained by using the oxygen consumption of biosolids. Quantified savings in the form of needed volumes of air while still achieving sufficient COD reduction are presented. The tests have been made in a bubble column with pulp mill process water and sludge from a biological treatment plant. These were supplemented with case studies at three pulp and paper mills.

Characterization and Dewatering of Activated Sludge from the Pulp and Paper Industry

1993 ◽  
Vol 28 (1) ◽  
pp. 193-201 ◽  
Author(s):  
J. Pere ◽  
R. Alen ◽  
L. Viikari ◽  
L. Eriksson
Keyword(s):  
Activated Sludge ◽  
Paper Industry ◽  
Pulp And Paper Industry ◽  
Contact Angles ◽  
Low Ph ◽  
Pulp And Paper ◽  
Hydroxyl Groups ◽  
Ftir Analysis ◽  
Floc Properties ◽  
Filter Cakes

Floc properties and dewatering of activated sludge from the pulp and paper industry were studied prior to and after an oxidative conditioning using Fenton's reagent Sludge samples were taken from four treatment plants, which differed with respect to organic loadings and wastewater source. Poor dewaterability was typical of heavily loaded sludges and a positive correlation between filtrability and the concentration of exopolysaccharides was observed. Oxidative conditioning improved the dewaterability of all the sludges tested, but especially that of heavily loaded sludges. Lab-scale piston press results were also comparable with those of controls conditioned with polyelectrolytes. As a result of the conditioning, the surface charge density of the flocs decreased and the contact angles of filter cakes were increased, which enhanced flocculation and settleability. It is possible that hydroxyl groups are oxidized during the oxidative treatment to carboxyl groups, which are more hydrophobic at low pH. This hypothesis was partly supported by FTIR-analysis, but obviously other mechanisms were also involved.

Forests, fiber, and the environment – In view of the fiber supply to the pulp and paper industry

1999 ◽  
Vol 75 (2) ◽  
pp. 247-255 ◽  
Author(s):  
Dinesh Mohta ◽  
D. N. Roy
Keyword(s):  
Raw Materials ◽  
Paper Industry ◽  
Wood Fiber ◽  
Pulp And Paper Industry ◽  
Developed Countries ◽  
Wood Pulp ◽  
Vital Role ◽  
Pulp And Paper ◽  
High Yield ◽  
Paper Mills

Forests play a vital role in the social, economic, and environmental development of any country. Paper, composed principally of wood fiber, is an essential commodity in promoting literacy, communication, documentation, and packaging. However, there is much concern about the world's forests being over-utilized. This has led to serious repercussions, not only to humanity, but also to the earth's biodiversity as a whole. It is now time that forests be used in a more responsible and ethical manner. Because of reduced forest area, increasing pulpwood costs, and an increasing demand for pulp and paper products, it might be expected that the focus would shift to high yield pulping processes or to the use of cellulosic non-wood raw materials. Non-woods are available in good supply all over the world, but are currently under-utilized. It is estimated that replacing 5–10% of wood pulp with non-wood pulp would have an important impact on the conservation of forests and the environment. This replacement of wood pulp by non-wood pulp could be environmentally and economically acceptable even in developed countries. By doing so, pulp and paper mills would have a lead role in reducing their dependency on forests for fiber. This determination and commitment would enhance the long-term sustainability of forests and the pulp and paper industry. Above all, it would be a sustainable step towards "our common future." Key words: forest, sustainable development, fiber supply, pulp and paper, non-woods

Evaluation of Purification Efficiency of Activated Sludge Treatment Plants for Pulp and Paper Industry Wastewaters in Finland

1990 ◽  
Vol 22 (9) ◽  
pp. 199-206
Author(s):  
J. Junna ◽  
J. Rintala
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Paper Industry ◽  
Pulp And Paper Industry ◽  
Pulp And Paper ◽  
Pulp Mills ◽  
Sludge Treatment ◽  
Actual Performance ◽  
Loading Rates ◽  
Removal Efficiencies

Since 1984, when the first activated sludge treatment plant (ASTP) was built to treat pulp and paper industry wastewaters in Finland, twenty more plants have been introduced by 1989. An evaluation was undertaken to find out the actual performance of the ASTPs in BOD7, CODc r and phosphorus removal. The evaluation included all the 12 ASTPs in operation in the pulp and paper industry at the beginning of 1987. The highest average BOD7 removals were about 90 % at pulp mills as well as paper and board mills. CODc r removal was generally higher at paper and board mills (about 40-70 %) than at pulp mills (about 25-55 %). Phosphorus was added to wastewater in most plants. In some ASTPs, phosphorus concentrations were lowered by 20-40 % compared with wastewater from the mill. In some plants phosphorus load on the recipient was higher than the load coming from the mill. In treated wastewater, correlations between suspended solids and BOD7, CODc r, phosphorus and nitrogen were significant in most plants. This indicated that low removal efficiencies resulted from poor suspended solids removal in the secondary clarification. Volumetric and sludge CODc r loading rates could not explain removal efficiencies when all plants were included in the comparison. In plants treating chemical pulping effluents, higher removal efficiencies were normally achieved with lower loading rates. When the plants were studied separately, the influence of loading rate was generally significant.

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.

Nutrient minimisation in the pulp and paper industry: an overview

2004 ◽  
Vol 50 (3) ◽  
pp. 111-122 ◽  
Author(s):  
A.H. Slade ◽  
R.J. Ellis ◽  
M. van den Heuvel ◽  
T.R. Stuthridge
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Paper Industry ◽  
Pulp And Paper Industry ◽  
Pulp And Paper ◽  
Treated Wastewater ◽  
Nitrogen And Phosphorus ◽  
Treatment Technology ◽  
Solids Separation ◽  
The Impact

This paper reviews nutrient issues within the pulp and paper industry summarising: nitrogen and phosphorus cycles within treatment systems; sources of nutrients within pulping and papermaking processes; minimising nutrient discharge; new approaches to nutrient minimisation; and the impact of nutrients in the environment. Pulp and paper industry wastewaters generally contain insufficient nitrogen and phosphorus to satisfy bacterial growth requirements. Nutrient limitation has been linked to operational problems such as sludge bulking and poor solids separation. Nutrients have been added in conventional wastewater treatment processes to ensure optimum treatment performance. Minimising the discharge of total nitrogen and phosphorus from a nutrient limited wastewater requires both optimised nutrient supplementation and effective removal of suspended solids from the treated wastewater. In an efficiently operated wastewater treatment system, the majority of the discharged nutrients are contained within the biomass. Effective solids separation then becomes the controlling step, and optimisation of secondary clarification is crucial. Conventional practice is being challenged by the regulatory requirement to reduce nitrogen and phosphorus discharge. Two recent developments in pulp and paper wastewater treatment technologies can produce discharges low in nitrogen and phosphorus whilst operating under conventionally nutrient limited conditions: i) the nutrient limited BAS process (Biofilm-Activated Sludge) which combines biofilm and activated sludge technologies under nutrient limited conditions and ii) an activated sludge process based on the use of nitrogen-fixing bacteria. Aerated stabilisation basins often operate without nutrient addition, relying on settled biomass in the benthal zone feeding back soluble nutrients, or the fixation of atmospheric nitrogen. Thus effective nutrient minimisation strategies require a more detailed understanding of nutrient cycling and utilisation. Where it is not possible to meet discharge constraints with biological treatment alone, a tertiary treatment step may be required. In setting nutrient control guidelines, consideration should be given to the nutrient limitations of the receiving environment, including other cumulative nutrient impacts on that environment. Whether an ecosystem is N or P limited should be integrated with wastewater treatment considerations in the further design and development of treatment technology and regulatory guidelines. End-of-pipe legislation alone cannot predict environmental effects related to nutrients and must be supplemented by an effects-based approach.

Sign in / Sign up

Export Citation Format

Share Document