Effect of Hydraulic Retention Time on the Treatment of Pulp and Paper Industry Wastewater by Extended Aeration Activated Sludge System

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.

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Bioremediation Approaches for Treatment of Pulp and Paper Industry Wastewater: Recent Advances and Challenges

Microbial Bioremediation & Biodegradation ◽

10.1007/978-981-15-1812-6_1 ◽

2020 ◽

pp. 1-48 ◽

Cited By ~ 1

Author(s):

Vineet Kumar ◽

Indu Shekhar Thakur ◽

Maulin P. Shah

Keyword(s):

Paper Industry ◽

Pulp And Paper Industry ◽

Pulp And Paper ◽

Recent Advances ◽

Industry Wastewater

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

Water Science & Technology ◽

10.2166/wst.1988.0005 ◽

1988 ◽

Vol 20 (1) ◽

pp. 25-36 ◽

Cited By ~ 2

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.

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