Paper industry is a vital part of a sustainable EU economy; the cluster with the forest industry generates an annual turnover of more than 375 billion Euros, i.e. 6.5% of the European manufacturing industry’s turnover. Water consumption varies widely from 1-2 m3/t in brown products to more than 20 in white products depending on the grade, raw materials and used process. In this sector a lot of effort has been made during the last decades for water saving, closing water circuits and reducing substantially the environmental impact. Even knowing that the paper industry is the leading sector in relation to separation of loops, recycling process waters, advance strategies for internal and external water reclamation and reuse, it is still the second largest industrial sector in terms of water consumption.
There are still several bottlenecks to overcome when moving towards a zero effluent system. In many cases a number of problems around the removal of substances are not solve yet and further closing the water cycle causes other problems affecting machine runnability or paper quality. These technical limits are included in the strategic research agenda of the European Forest Based Platform as clallenges to solve if we want to achieve a further reduction of fresh water consumption. Therefore, new water sources need to be considered, new water purification systems need to be developed and new concepts based on the integration of available and emerging technologies have to be implemented, as also mention in the strategic research agenda of the European Water Supply and Sanitory Technology Platform
The new concepts need to be adapted to the specific needs of the sector and viability studies need to be carried out, at laboratory and pilot plant scale, considering technical and economical aspects as well as potential reduction in energy consumption.
Three paper companies as water consumers
have joint forces in close collaboration with leading water treatment suppliers and RTO with in AquaFit4Use:
To reduce fresh water consumption without affecting neither paper machine runability nor paper quality and to minimize the environmental impact of wastewaters in general or of specific target compounds in particular.
Integration of new technologies for reducing contamination load and removing recalcitrant contaminants from process waters and/or final mill effluents to achieve the water quality required for its reuse. Thus, tailor-made solutions are proposed for advanced water loop closure comprising:
• Use of reclaimed water (municipal and industrial) as fresh water;
• MBR process reliability tests on industrial waste waters and development of process monitoring sensors;
• Improving process runability by reduction of scaling and fouling problems;
• Improvement of process stability and product quality by the removal of specific components.
Tailor-made technologies verified in lab-scale (within subproject 3) are tested on-site (within subproject 5) alone and in treatment trains (covering six different pilot cases) based on seven advanced water treatment steps:
• 3FM High Performance Filtration System
• Anaerobic treatment
• Softening step
• Membrane Bioreactor MBR
• Ozone treatment
In addition to comprehensive on-site trials already performed during past 32 months (June 2008 – January 2010) at SAPPI (Figure 1), and Holmen (Figure 2 and 3) currently various physicochemical and biological wastewater treatment technologies are being in preparation to be considered at Hamburger Rieger (Figure 4) during coming 9 months (March – October 2011).
a circuit closure potential could be evaluated based on a systematic assessment and evaluation of the current state and the results of a simulation study. Within this project action plans with single measures, partly including several alternatives, were elaborated for a reduction of the specific fresh water consumption and an optimisation of the water circuits. The identified fresh water saving potential amounts to approximately 30 % of the current fresh water intake. Some of the proposed measures are already implemented or selected for future implementation.
In Holmen Paper
the best solution so far is the use of municipal reclaimed water as fresh water because of the limitations of RO recovery due to silica precipitation.
Viability studies shown the potential new solutions but also the current bottlenecks which are further studied (within subproject 3) e.g. silica removal before RO.
Pilot trials at Holmen Paper: Anaerobic + aerobic+ UF + RO treatments
Pilot trials at Holmen Paper: anaerobic + MBR + RO treatments
At Hamburger Rieger
All results achieved and analysed by considering the partners’ specific boundary conditions will serve as a valuable basis for subsequent tasks to be carried out in the frame of SP5’s pilots. Actually, the details of the pilot trials have been planned and discussed. The layout of pilot plants and corresponding treatment sequences has been fixed. For the paper sector following steps are scheduled to be performed in the time frame March to September 2011, i.e. anaerobic treatment, Calcium elimination & softening, MBR, ozone, evapoconcentration and membrane filtration (NF/RO).
Pilot trials scheduled for Hamburger Rieger