Energy efficient aeration of wastewaters from the pulp and paper industry

2010 ◽  
Vol 62 (10) ◽  
pp. 2364-2371 ◽  
Author(s):  
M. Sandberg

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.

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.


1996 ◽  
Vol 1 (4) ◽  
pp. 379-401 ◽  
Author(s):  
David A. Sonnenfeld

This paper analyzes how a key conflict in Australia's pulp and paper industry became generalized to other sites through environmental action, government regulation, and industry initiative. From 1987–91, Australians debated construction of a new, world-class, export-oriented pulp mill in Tasmania. Rural residents, fishermen, and environmentalists, allied with the Australian Labor Party, succeeded in scuttling the project. Subsequently, the national government launched a major research program, state governments tightened regulations, and industry reduced elemental chlorine use. Any new mills constructed in Australia today would be among the cleanest in the world. This paper is part of a larger, comparative study of technological innovation in the pulp and paper industries of Australia, Indonesia, Malaysia, and Thailand. The author interviewed industry officials, government regulators, research scientists, and environmentalists; visited pulp and paper mills; attended technical conferences; and conducted archival work in these countries during a 12-month period.


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.


1994 ◽  
Vol 29 (5-6) ◽  
pp. 11-18 ◽  
Author(s):  
Howard Edde

The focus of this paper is on the earlier, recent and future developments in closing the water circuits in pulp and paper production. During the 1960s the U.S. pulp and paper industry was in its environmental infancy concentrating mainly on removal of settleable solids and initiating river assimilative capacity studies. The 1970s began with environmental legislation having enforceable powers to achieve primary and secondary (biological) treatment which was fundamentally fulfilled during the 1980s. The late 1980s and early 1990s opened with toxicity becoming the major environmental issue as measured mainly by absorbable organic halogens (AOX) and dioxins. This paper identifies progress and key technological developments towards furthering stringent environmental enhancement and provides additional knowledge requirements leading into the next century.


Author(s):  
Micaela A. R. Soares ◽  
Manuela Marques ◽  
Maria Teresa Rodrigues

The feasibility of storing wastewater samples from pulp and paper industry during more than 5 days (time recommend by ISO 5667-3:2018) for AOX determination was addresses in this study. Samples were collected before and after the aerobic biological treatment of a Portuguese industry. Experimental protocol included AOX measurements at days 4, 5, 6, 8, 11, 13, 15, 18 and 20 after sampling. Results obtained indicate that storage time is not matrix-dependent and it can be extended up to 20 days, which clearly improves management of laboratory activities concerning AOX determination.


1999 ◽  
Vol 75 (2) ◽  
pp. 247-255 ◽  
Author(s):  
Dinesh Mohta ◽  
D. N. Roy

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


TAPPI Journal ◽  
2014 ◽  
Vol 13 (6) ◽  
pp. 9-15 ◽  
Author(s):  
TROY RUNGE ◽  
JACKIE HEINRICHER ◽  
DAN MEIER

Bamboo is one of the world’s fastest growing feedstocks and represents a promising nonwood resource that can be utilized in the pulp and paper industry. The timber varieties offer low feedstock costs, can be processed similarly to trees from a logistics standpoint, and have useful fiber properties for papermaking. Plantations have not yet been established due to propagation costs, limiting adoption of bamboo as a pulp feedstock to smaller pulp mills primarily in China, where there are native forests. Recent advances in micropropagation may allow lower establishment costs, but gradual introduction into the supply chain will be required. One concept is to gradually include bamboo feedstock into an established pulp mill as plantations are established, using co-cooking with a wood species. Previous work has shown that bamboo cooks fairly easily using the kraft process with conditions similar to hardwood species.


2007 ◽  
Vol 55 (6) ◽  
pp. 117-123 ◽  
Author(s):  
C.R. Oliveira ◽  
C.M. Silva ◽  
A.F. Milanez

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.


2013 ◽  
Vol 8 (3-4) ◽  
pp. 359-374 ◽  
Author(s):  
M. J. Kossar ◽  
K. J. Amaral ◽  
S. S. Martinelli ◽  
M. C. L. Erbe

The reuse of wastewater by the pulp and paper industry reduces environmental impacts by contributing to raw water conservation, thereby making a greater volume of fresh water available for nobler purposes, and reducing wastewater treatment. This study evaluated a proposed system of water reuse at a Kraft pulp and paper plant in Brazil, based on a survey of water quality required by its consumption points, supplied by its water treatment plant. Results after ultrafiltration included: turbidity of 0,3 NTU and pH 7,5, average values of BOD 66,4 mg/L, COD 9,6 mg/L and the colour of 280,5 ppm Pt were measured after ultrafiltration. The ultrafiltered wastewater was considered available for reuse, and its quality was compared with that of the water supplied by the water treatment plant, which provided for the classification of potential reuse points. Water colour was identified as the limiting factor for reuse; thus the reuse points were two Kraft paper machines, and the water flow to the liquid ring formations that generate the vacuums inside nineteen pumps for these two machines. The advantages of this proposal for water reuse include: ultrafiltered water quality sufficient for the vacuum pumps, the small distance between the point of reused water generation and the paper machines section, and the reused water has no contact with the final product. The calculated cost and return time for the water reuse system was US$ 607.020,00 in 15 years.


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