In co-operation with the institute PTS, recycling paper mill OUDEGEM and suppliers of water treatment plants PAQUES and KOCH-GLITSCH, a new integrated water treatment concept on thermophilic conditions was successfully developed within the framework of an European R&D project, comprising thermophilic anaerobic treatment as a first stage, aeration (and if needed further separation) as a second stage, and membrane technology as a third stage. This concept referred to as "KIDNEY TECHNOLOGY" appears to be a very, promising step on the way to achieving zero-effluent mill circuits without increasing the concentration of organic and inorganic loads. Trials were conducted in lab and small-pilot scale with highly loaded process waters of a Belgian paper mill on its way to full circuit closure. Pilot and full-scale tests using the UASB/IC reactor of PAQUES and pilot-scale tests using the UF- and RO-units of KOCH-GLITSCH were carried out at the mill site, and have already confirmed some of these promising results achieved in lab / small-pilot scale at PTS.
In co-operation with the institute CEIT, recycling paper mill SAICA and suppliers of water treatment plants CADAGUA and KOCH-GLITSCH, a new integrated water treatment concept on thermophilic conditions was developed within the framework of an European R&D project, comprising softening step as a first stage, thermophilic aerobic treatment as a second stage, and membrane bioreactor as a third stage. However some technical problems remain to be solved. The aerobic thermophilic treatment of effluents produced by anaerobic treatment was tested in a laboratory system at CEIT during a period of six months. The tests were carried out under different operational conditions to determine the biodegradation rates achievable by this treatment method. On this basis trials at paper mill SAICA were performed in pilot scale. This process has shown to be technically feasible, but because of economical reasons / technical problems it does not pay off at the moment.
The European paper industry produces 70 million tonnes of paper annually and at the same time uses an average of 20 m3/t (1.4 billions m3 of water annually). Paper and board production therefore is one of the most water intensive industrial processes. The reduction of wastewater has already led to a re-circulation rate of more than 90% of the water and some mills even produce paper in a closed cycle. This results in severe quality deterioration and a drop of productivity (machine failures, slime formation, odour), which often force paper makers to reopen their system again. Existing treatment technologies for closed loop operation show significant limitations. The objective of the proposed research work is to develop a suitable treatment technology (kidney technology) for closed cycle operation in order to realise effluent free paper production.
Two different approaches to integrated treatment are to be investigated:
- Pressurised thermophilic aerobic treatment with integrated biomass separation via membrane or flotation and;
- Thermophilic anaerobic treatment combined with ultrafiltration. The technology to develop is to be operated at increased temperatures enabling paper production at 55 60(0)C with significant positive effects on productivity (+5 %)and energy consumption (>-5 %). Due to high biomass concentrations (20-25g/l), high temperatures and the use of membranes the treatment technology will require less space in installation. Waste production can be reduced sharply in relation to existing technologies (-40 to -90%). The specific COD loading rate of the biological stage will be increased (> +50%) compared to conventional (mesophilic) treatment.
The kidney technology should be operated with little energy consumption or should even produce energy. This process will significantly improve the quality of recycled water due to the use of membrane technology. The technology will be developed for systems producing packaging grades from 100% waste paper. The results can also be used to develop kidney technologies for higher paper grades and other branches of industry with high organic loads in waste waters (e.g. food etc.) and extensive water use. Lab scale tests for process development and pilot scale tests (in 2 paper mills) will be carried out for both technologies. A detailed mill scale implementation study will be conducted in the participating paper mills. The consortium comprises two research institutes with specific know how on paper production and biological degradation (PTS and CEiT), three suppliers of wastewater treatment (CADAGUA, KOCH and PAQUES) and two paper mills as end users of kidney technology producing packaging grades (SAICA and VPK). IMT Areas covered by the proposal are 1.2.2 M, 1.2.2 S, 1.2.3 S, 1.3.1 M, 1 .1.1. S
Funding SchemeCSC - Cost-sharing contracts
20009 San Sebastian
8560 AB Balk