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

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.

2018 ◽  
Vol 77 (8) ◽  
pp. 2068-2076 ◽  
Author(s):  
Björn Magnusson ◽  
Eva-Maria Ekstrand ◽  
Anna Karlsson ◽  
Jörgen Ejlertsson

Abstract The activated sludge process within the pulp and paper industry is generally run to minimize the production of waste activated sludge (WAS), leading to high electricity costs from aeration and relatively large basin volumes. In this study, a pilot-scale activated sludge process was run to evaluate the concept of treating the wastewater at high rate with a low sludge age. Two 150 L containers were used, one for aeration and one for sedimentation and sludge return. The hydraulic retention time was decreased from 24 hours to 7 hours, and the sludge age was lowered from 12 days to 2–4 days. The methane potential of the WAS was evaluated using batch tests, as well as continuous anaerobic digestion (AD) in 4 L reactors in mesophilic and thermophilic conditions. Wastewater treatment capacity was increased almost four-fold at maintained degradation efficiency. The lower sludge age greatly improved the methane potential of the WAS in batch tests, reaching 170 NmL CH4/g VS at a sludge age of 2 days. In addition, the continuous AD showed a higher methane production at thermophilic conditions. Thus, the combination of high-rate wastewater treatment and AD of WAS is a promising option for the pulp and paper industry.


2010 ◽  
Vol 62 (2) ◽  
pp. 387-393 ◽  
Author(s):  
H. Kyllönen ◽  
J. Lehto ◽  
P. Pirkonen ◽  
A. Grönroos ◽  
H. Pakkanen ◽  
...  

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.


1988 ◽  
Vol 20 (1) ◽  
pp. 25-36 ◽  
Author(s):  
A. Luonsi ◽  
J. Junna ◽  
I. Nevalainen

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.


2019 ◽  
Vol 5 (4) ◽  
pp. 185-198 ◽  
Author(s):  
Patrik Söderholm ◽  
Ann-Kristin Bergquist ◽  
Kristina Söderholm

Abstract Purpose of Review In this article, we review existing research addressing how environmental regulations have influenced the pulp and paper industry. These regulations appear in different forms and designs and address air and water pollution as well as climate change. The paper devotes particular attention to how various regulations have affected sustainable technological change and the prospects for inducing deep emission reductions without jeopardizing industrial competitiveness and future investments. Recent Findings Experiences from key pulp and paper regions, not least the Nordic countries, suggest that gradually tightening performance standards have contributed to radical reductions in emissions, e.g., chlorine compounds and biological oxygen demanding agents, and without imposing excessive compliance costs. This outcome can largely be attributed to how the regulations have been designed—and implemented—in practice, as well as to the presence of efficient and legitimate institutions. Long-term emission reduction targets, in combination with extended compliance periods and trustful firm-regulator relationships, contributed to radical technological innovation and permitted radical emission reductions without excessive compliance costs. The development of alternative bleaching technologies is an apt example. In contrast, the impact of carbon pricing schemes, including the EU emissions trading scheme, on carbon dioxide emissions reductions and related technological change in the pulp and paper industry has however been modest. Self-regulation, certification, and community pressure have exerted relatively modest influences on the environmental performance of the industry. Summary Important avenues for future research are identified. These include the following: (a) comparative research on how policy mixes in various countries have influenced environmental compliance and innovation; processes; (b) future studies of environmental regulations, their design and implementation, in emerging pulp and paper producing countries, not least China; and (c) research on how environmental regulations can affect ongoing restructurings in the industry towards a broader palette of products in biorefineries.


Sign in / Sign up

Export Citation Format

Share Document