Version 4.11 is available for free download as PDF-file.
The book in english Language is available in book shops using the ISBN 978-3-8334-6698-4 (BOD Norderstedt, Germany: 2006). A read only version is available for download.
The script is available for free download as PDF-file.
A PDF-version of our company profile
can be downloaded.
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Dr. Christian H. Möbius, Muesmannstr. 15 g, DE-86199 Augsburg , Tel. +49 821 994120, Fax +49 821 994121, Mobiltel. +49 171 1244284, E-Mail: cm@cm-consult.de
Dipl.-Ing. Alfred Helble, Lehenstraße 48, DE-70180 Stuttgart, Tel. +49 711 6071381, Fax +49 711 6071389, Mobiltel. +49 160 97931254, E-Mail: ah@cm-consult.de
Partnerschaftsgesellschaft Headquarter Augsburg
Branch Office Stuttgart
Internet www.cm-consult.de,
E-Mail: info@cm-consult.de
This report gives information about our activities in the year 2010.
On behalf of our clients we continue dealing with the following areas in the year 2010:
Several companies and corporate groups were advised continuously in all aspects of technical environmental protection and environmental management, especially risk analysis and risk management (have a look at our reference list, please). Concepts for improvement of wastewater treatment plants to reach better elimination, improved performance and expansion of treatment capacity as well as for new plants for treatment of effluent part streams have been worked out. Concepts for integrated treatment (kidney systems) are asked for, using MBR technology as well.
The putting into action of such concepts was accompanied (preparation of tenders, bid comparison, technological guarantees, monitoring of execution, approvals and performance tests). Total costs considerations for different ways to fulfil legal requirements, feasibility studies for implementation of new technology to meet legal requirements for increased input load due to increased production as well as assessment of environmental emission data compared to BAT rules given in the BREF document pulp and paper were carried out.
Wastewater Treatment Plants: Variant studies, concept development, concept design, assessment of offers, assessment of concept and performance, assessment of the available capacity in regard to projected changes of stock composition and/or increased production capacity, considerations regarding economic and ecologic efficiency of part stream treatment. Performance of wastewater treatment plants was evaluated, optimization possibilities were shown. Assessment of new methods (for instance MBR or EGSB) with a view to suitability for the task, operational safety and expected operating costs. Accompanying of start-up and optimization of the plants basically designed by us. Concepts for pretreatment or complete treatment for direct discharge for mills now discharging to public wastewater treatment plants had to be prepared.
Wastewater Cooling: Preparation of cooling concepts for part streams, effluent full stream with special regard to cost effectiveness, energy required and environmental impact (odour and vapour).
Problems in Effluent Treatment: Problem diagnosis, immediate measures and long-term remedy measures, stabilisation by change of the operational parameters, suggestions for improvement in the technical equipment, concept development for long term remediation. Analysis of the technical aspects of possible legal consequences.
Advanced Effluent Treatment: Advanced treatment of paper mill wastewaters in the sense of an elimination of organic substances beyond the effect of cleaning mechanical biologically is demanded increasingly to protect the receiving waters. We develop these concepts and compare various methods such as the use of membrane bioreactors, membrane treatment methods, the chemical biochemical oxidation and the evaporation, depending on the local situation. Checking the ozone-biofilm-process partly developed by us remains of current interest. The process is in operation in mills in Germany and Austria. In 2009 again concepts for use of this process have been designed by CM Consult.
Indirect Discharge: Expert forecast of discharge values to be expected; discussion of the dependence of concentrations of the short-term wastewater flow rate; assessment for the conversion to direct discharge and development of suitable treatment plant concepts. Support with applications and fixing of conditions for discharge regulatory limits. Support in technical discussion with the operator of the public treatment plant.
Charges for Wastewater Discharge (German Wastewater Charge Act): Declaration of standards to be adhered to (with statistical evaluation of parameters and forecast of final values), cost saving by consequent application of the current law, exploiting all possibilities to deduct investment costs from discharge costs, calculation of discharge costs for the next years, development of long time strategies for settling of the investment costs of stepwise realized concepts for the gradual implementation of new techniques in the wastewater treatment.
System for Environmental Reporting: Continuous improvement and further development of evaluation data files based on standard user software, which automatically produces monthly and annual reports, including monitoring reports demanded by authorities. The evaluation files supply data for all required calculations and statistical evaluations as well as graphic representations of monitoring data. This permits easy regular of the plant operation and allows rapid diagnosis of the causes of faults for trouble shooting. The system provides full information to the regulatory authorities as is demanded. Where environmental management systems are used, these reports are an essential component of the system. The files are part of the constant inventory of the management instruments of some of our clients and are continuously improved using the applicable newest software versions.
Technical concepts for sludge dewatering and drying, concepts to minimize biological excess sludges, total costs comparisons; methods to advantageously utilise wastes, pre-treatment measures, avoidance of offensive smells.
Investigation program, assessment, and technical transfer to reduce water consumption by specific measures without impairing production or quality. Discussion of internal waste and emission avoidance measures. Assessment of key figures and derivation of reengineering programs. Development of concepts for closing the water cycles with technical economic comparison of internal and external treatment concepts for the recycling water. Forecasts of changes in water cycle as well as effluent quality and temperature when internal treatment methods are implemented and / or treated effluent is recycled.
Membership of both partners in the
ZELLCHEMING Committee for environmental protection (FA ENVI) and
of A. Helble in the subcommittees "Water/ Wastewater" and "Solid
Wastes".
Both partners are members of project assisting boards for R&D
projects. Membership of both partners in the IWA Specialist Group on
Forest Industry; A. Helble is registered referee for IWA.
C.H.Möbius participates in DWA working group IG-2.20 "Abwasser und
Abfälle aus der Papierindustrie" (Wastewater and solid wastes from
paper industry).
C.H. Möbius had a block lecture on protection of surface waters and wastewater treatment for paper mill engineering students in the Academy for Cooperative Education of Karlsruhe / Gernsbach (Germany).
C.H. Möbius has actualised and revised his book “Wastewater of Pulp and Paper Production”. The German version of the book as well as the German version of the revised booklet "Pollution Abatement and Wastewater Treatment" is ready for download on the website www.cm-consult.de under publications.
Order a printed copy of the 'Briefing Report 2010'
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Download Adobe Acrobat® PDF-Reader from Adobe Website (click here:
download).
The membrane bioreactor process (MBR) is a well developed and proven technology. The membrane materials and module systems have been developed continuously within the last years. Several installations have been built for municipal and industrial applications, but only few full scale MBR plants are in operation in pulp and paper industry.
The MBR process is an alternative for the aerobic treatment of papermill effluent. The system is able to replace the standard process high loaded stage followed by a low loaded activated sludge system with at least the same process efficiency and stability. The high loaded stage generally will be an aerobic suspended carrier reactor, or, leaving the aerobic system, an anaerobic reactor of the type EGSB (Extended Granulated Sludge Blanket).
MBR for industrial applications consists of an activated sludge bioreactor followed by an external side stream membrane stage for the separation of biomass. Essential advantages of this technology are the high process stability because of assured biomass retention, less area required due to a high volume load and no need of a secondary clarifier as well as a treated water quality almost free of suspended solids, giving best preconditions for reuse of treated waste water in the production.
However, using the MBR process for papermill effluent treatment the specific waste water characteristic such as size, type and quantity of remaining fibres, organic and inorganic compounds and typical load fluctuations in papermills have to be respected in the design of the pretreatment and the activated sludge bioreactor as well. Especially the bioreactor design and stable operation of the biostage will influence the overall process performance and reliability basically.
The available technical MBR systems using either low pressure submerged membranes or classical horizontal cross flow tubular modules or as a new development aerated vertical cross flow tubular modules are compared technically. Recommendations for planning are given. The technical and economical issues are examined in a case study. Basis of the process design is the model of a production of graphic paper according middle European practice with regard to production capacity, raw materials, stock preparation and specific waste water amount. For this model waste water, the MBR process is designed and investment and operation costs are determined.
The total specific operation costs for MBR with submerged membranes and with aerated tubular cross flow membranes amount to 0.22 €/m3. MBR with classical tubular cross flow membranes amount to 0.33 €/m3 mainly due to fact of the higher energy cost. However, the calculated specific total annual costs (capital + operation costs) are in a narrow range (0.56 €/m3 to 0.59 €/m3).
Order a printed copy of manuscript 184_m2903 (click here: order) or download it as PDF-File (click here: download).
Following a short description of the situation 30 years ago and the indication of what we learned by studying the plants in operation, the best available technology today for treating pulp and paper mill effluent is described. Searching for the relevant information, we found that mainly three points are crucial for a success in biological treatment:
The best available technology is characterized by two stage biological treatment plants avoiding the risk of sludge bulking in the final stage, usually an activated sludge reactor, and giving the possibility to operate at a rather low BOD sludge load, which is crucial for good COD elimination.
In some cases the best possible biological elimination of organics is not good enough to protect the receiving water. Then an advanced treatment is necessary. Usually this only will be relevant in cases where production is increased substantially at a site.
New tasks will arise not only by new legal rules and tougher limits, but also when new parameters for quality limits of pulp and paper industry effluents are taking effect.
Order a printed copy of manuscript 183_m2902 (click here: order) or download it as PDF-File (click here: download).
Constant capacity increases, rising quality requirements, changes in raw material and aids and in production processes can cause diminished purification efficiency of environmental technical installations and thus (massive) failures. The operators often have a hard time identifying the cause simply by evaluating process data alone at the time of the failure.
Unplanned immediate measures up to production slow-down will increase operational risks while trying to resolve the incident. Technical plant optimisation and expansion measures take time and increase the risk of non-compliance with legal requirements. Implementing an environmental risk management system allows you to continually evaluate – by applying suitable risk analysis methods – the danger of technical and technological risks originating in processes that potentially affect the environment; it also helps to prevent these risks from arising uncontrollably. A well-proven method in that respect is to evaluate risks by establishing evaluation categories for potential risks and their classification in a frequency and effect matrix.
Examples taken from the waste water and waste disposal sectors and from plant incident safety will demonstrate the available categories of the risk areas in question and – in concrete case histories - the necessary measures in order to avoid risks.
Order a printed copy of manuscript 182_m2803 (click here: order) or download it as PDF-File (click here: download).
Concepts for wastewater treatment of pulp and paper mill effluents can be developed regarding longtime experience with rules for design considering production and site specific conditions and requirements as well as regional legal requirements. Basic quality standard is always best available technique (BAT).
Present state of the art standard processes are mechanical or chemical mechanical pretreatment followed by biological stages, generally consisting of an anaerobic or aerobic high loaded first stage followed by a low loaded aerobic bioreactor, generally an activated sludge treatment process. Alternatively to these the membrane bioreactor (MBR) as aerobic one stage process may be quoted as a biological standard process as well nowadays, due to a continuous development of this process.
Aerobic high loaded stages are generally using the suspended carrier biofilm process (also called moving bed biofilm reactor MBBR). Anaerobic high loaded stages are using the expanded granular sludge blanket process (EGSB). In case of the anaerobic process as first biological stage the energetic use of the biogas is an essential part of the economic considerations, especially when a refund may be expected in case of production of so called green energy, like in Germany from the EEG („Erneuerbare Energien Gesetz” or renewable energy act). The low energy demand and the low production of biological excess sludge are further economic (and ecologic) advantages of the anaerobic process.
The advantages of the MBR process – which as a single stage process has to be compared to aerobic two stage processes – are smaller bioreactor volume (due to higher biomass concentrations) and no secondary clarifier due to the membranes retaining the activated biomass. The MBR therefore needs much less area compared to a standard aerobic system. The treated effluent is virtually free of suspended solids. The MBR is predestined for internal water circuit treatment in papermills (kidney systems) and treated waste water reuse.
Comparing these processes requires modeling a standard effluent which has to be treated with the systems designed following standard conditions (BREF).
For the different processes technological aspects, invest and operation costs as well as space requirement of the plant are compared. In case of reuse of the treated effluent additional aspects have to be regarded, which will be discussed generally.
As a result of the comparison objective data as basis of a decision between the up to date state of the art wastewater treatment processes are given.
Order a printed copy of manuscript 181_m2802 (click here: order) or download it as PDF-File (click here: download).
The standard process for treatment of waste water from pulp and paper industry according the state of the art is chemical-mechanical pretreatment followed by a biological high load stage and a low load activated sludge system (the high load stage being an aerobic or anaerobic reactor). An alternative process for the aerobic case is the membrane bioreactor (MBR). On one hand an MBR may simply replace the activated sludge stage after a high load reactor but on the other hand the system is able to replace both, the aerobic high load reactor and the low load stage, with the same process efficiency and stability.
The separation of biomass in the MBR process is achieved by membrane modules either immersed inside the aeration basin or installed outside. Essential advantages of this technology are the high process stability because of assured biomass retention, less area required due to a high volume load and no need of a secondary clarifier as well as a treated water quality almost free of suspended solids, giving best preconditions for reuse of treated waste water in the production.
The MBR process is a well developed and proven technology, but only few full scale MBR plants are in operation in pulp and paper industry. Generally it can be assumed that investment and operation costs of the MBR process are higher compared to a standard system. These higher costs have to be balanced against the verifiable advantages.
The target of this paper is to present a detailed technical and economical comparison between a standard system consisting of a suspended carrier reactor as the aerobic high loaded stage followed by a conventional low loaded activated sludge system with secondary clarifier with the MBR process. The required treatment quality parameters for both processes are defined by state of the art criteria (German Annex 28, BREF).
Basis of the process design is the model of a production of graphic paper according middle European practice with regard to production capacity, raw materials, stock preparation and specific waste water amount.
For this effluent model, assuming the mentioned effluent quality requirements, the standard process and the MBR are designed in detail and investment and operation costs are determined.
The comparison results in 30% higher investment and 67% higher total annual costs (capital plus operation costs) for the MBR process compared to the standard process suspended carrier reactor plus conventional activated sludge system as 100%. The higher costs have to be justified by the advantages of a substantially lower space requirement and a treated waste water quality well applicable for reuse.
Another alternative concept taking a suspended carrier reactor plus an MBR into account is only considered qualitatively, as preliminary examinations have shown that the higher costs do not compensate the advantages by far.
The study shall provide a basis to decide in which cases the MBR process compared to a standard concept should be examined in detail.
Order a printed copy of manuscript 179_m2601 (click here:order) or download it as PDF-File (click here: download).
A process of advanced oxidation treatment discussed here has been developed in the last seven years. A technical plant for treatment of paper mill wastewater started operation in 1999. Advanced oxidation treatment is defined here as a combination of chemical and biochemical oxidation applied to a completely biodegraded effluent. The process is a combination of ozonation with following biodegradation in a biofilm reactor. The combination makes use of the effect of partial oxidation in which with reduced use of expensive chemical oxidants persistent COD becomes biodegradable. A far-reaching elimination of AOX, colour and other disturbing substances like complexing agents is achieved simultaneously. The partially oxidized compounds, now biodegradable, are eliminated in a following biofilm reactor.
Using single stage systems, COD elimination rates of up to 60% are achieved with 0.4 to 1.0 g ozone per g COD eliminated in the combined process. With a two stage system COD elimination of 85% with 0.65 g/g has been achieved in pilot tests.
The quality of the treated effluent suites fresh water requirements for most types of paper production, so that either a total closure of the water circuits or – due to increasing concentrations of electrolytes, which are not eliminated by this process – a substantial closure to about 20% of the original amount of fresh water can be achieved.
Order a printed copy of manuscript 172_m2301 (click here: order or download it as PDF-File (click here: download).
Anlagen zur Reinigung von Zellstoff- und Papierfabriks-Abwässern werden nach dem St. d. T. entsprechenden Regeln konzipiert, wobei abhängig von der Art der Produktion und des daraus resultierenden Abwassers bestimmte bevorzugte Verfahrenskombinationen zur Anwendung kommen. Soweit bestehende Abwasserreinigungsanlagen (ARA) hinter dem St. d. T. zurück bleiben, muss eine Sanierung vorbereitet werden. Unter Berücksichtigung des Anlagenbestandes, der vorhersehbaren zukünftigen Entwicklung des zu behandelnden Abwassers und vor allem der örtlichen Situation ist bei den zu prüfenden Konzeptvarianten das erforderliche Potential zur Leistungssteigerung und Optimierung der Gesamtreinigungsleistung einer ARA stets zu beachten. Vor diesem Hintergrund wurden Anlagen in den letzten Jahre häufig unter Einsatz des Schwebebettverfahrens mit Biomasseträgern konzipiert und erweitert. Einsatzmöglichkeiten dieses Verfahrens werden vorgestellt.
Über die aktuellen Betriebsergebnisse einer mit dem Schwebebettverfahren zur Leistungssteigerung umgerüsteten ARA einer großen Papierfabrik wird berichtet. In diesem Werk wurde das Sortenprogramm in den letzten Jahren kontinuierlich in Richtung auf hochweiße LWC (Tiefdruck)-Sorten entwickelt. Zur Einstellung der erforderlichen hohen Helligkeit der Rohpapiere wird der TMP-Anteil mit Wasserstoffperoxid unter Zusatz von NaOH gebleicht, was zu einer verstärkten Extraktion von schwerer abbaubarem CSB aus dem Holzstoff TMP und zu einer höheren Belastung der ARA mit organischen Stoffen (BSB und CSB) führt. Das zu entwickelnde Konzept erforderte daher eine deutliche Verbesserung der Gesamtreinigungsleistung, damit die Einleitqualität der vergangenen Jahre unter diesen Bedingungen erreicht werden konnte. Über die Umrüstungsmaßnahmen wird berichtet. Die Investitionskosten können mit der Abwasserabgabe der letzten 3 Jahre verrechnet werden, womit ein hoher Anteil der Investitionskosten gedeckt werden kann.
Order a printed copy of manuscript 170_m2204 (click here: order) or download it as PDF-File (click here: download).
The product grades of the Norske Skog Walsum mill have been continuously developed during the last few years towards LWC paper grades (gravure printing) with high brightness. Peroxide and sodium hydroxide are used for bleaching the thermo mechanical pulp (TMP) to achieve the required high brightness of the uncoated paper. The bleaching chemicals, especially the sodium hydroxide, are amplifying the extraction of hardly degradable substances from the TMP and are leading to a higher load with organic matter (BOD and COD) in the effluent treatment plant (ETP).
A concept for improved performance of the ETP was developed to achieve the discharge quality of the last few years under these conditions, insuring the reduction of the discharge loads below the required levels.
An essential bottleneck of biological treatment capacity before reconstruction was represented by insufficient elimination efficiency of the high loaded activated sludge stage followed by a flotation for intermediate clarification. This often resulted in an overload of the following activated sludge stage and the tertiary biofilters. The high loaded activated sludge stage was therefore re-built into a moving bed biofilm reactor (also called suspended carrier reactor) operated in two stages for efficient elimination of BOD and COD, decreasing the load of the activated sludge stage. The intermediate clarifier getting vacant was switched between the mechanical clarifier and the new cooling towers, to improve the removal of suspended solids. Besides additional modifications in the area of the second activated sludge stage and the sludge dewatering system, the tertiary biofilters were reconstructed.
After the optimisation period the BOD removal efficiency of the moving bed biofilm reactor is in the expected range of 60 to 80%. The following bio-stages can be relieved as expected. The advanced removal of soluble COD in the outlet of the secondary activated sludge system by the tertiary biofilter is achieved in the expected range accordingly.
Additional optimisation measures in the area of the moving bed biofilm reactor are planed to improve and stabilize the operation furthermore, having no influence on the efficiency, however.
From the actual point of view, the investment cost can be settled with the German wastewater discharge tax, covering a high share of the investment costs.
Order a printed copy of manuscript 168_m2201 (click here: order) or download it as PDF-File (click here: download).
The reuse of treated effluent after the advanced treatment is required, if a far-reaching minimisation of discharge into the receiving waters shall be obtained, as a general target. From the production point of view, an uncontrolled enrichment of detrimental substances and electrolyte in the circulation water must be avoided. If this can be managed, a substantial extension of the production capacity without increasing discharge can be achieved.
In integrated paper mills, the possibility arises to treat the main quantity and load (with effluent reuse) in the area of the pulp preparation (DIP, SGW, TMP) plus the supplementary treatment of the remaining effluent, compared to the external complete effluent treatment. As shown in a previous paper, the placed target can be reached most effective in the external complete effluent treatment in combination with advanced (tertiary) effluent treatment and systematic effluent reuse, if a step-by-step extension using the existing capabilities is realized. In this case, the external complete effluent treatment loses the character of an end of pipe solution totally, presumed that the water and stock cycle has been previously optimised. The distinction between internal and external loses its importance. Internal partial treatment concepts might cause lower cost (at lower load reduction) on a short-termed period, but obstruct an economic solution for the medium-termed attainment of a far-reaching load reduction.
If a paper mill plans the necessary measures in an effluent treatment plant considering an increasing production capacity with regard to the future, the possibilities for charging the investment cost against the cost for discharge of the effluent can be used in an optimal way.
This approach is expanded using typical models for the main types of paper products i. e. tissue (wood free), printing and writing (p&w, woodfree), magazine (wood containing), newsprint (DIP and mechanical fibers) and packaging (100% secondary fibers), each with a production capacity of 600 t per day.
The minimum achievable specific wastewater quantity and load is examined applying the complete effluent treatment. Advanced processes such as chemical-biochemical oxidation and - with a higher reuse rate - nanofiltration is required in addition to biological treatment in order to fulfil the required quality for the recycled wastewater and the final discharge of effluent.
Regarding the specific COD discharge to the recipient all concepts point out a significant reduction below 1 kg/t COD. The specific effluent discharge might be reduced to 1 - 2 m3 of effluent per t of produced paper. The specific total costs for the biological (at state of the art) and tertiary treatment range between 0.7 - 1.4 EUR/ m3 respectively 7 - 13 EUR/ t depending on the type of paper.
Assumed, that the measures for the attainment of the above mentioned specific data shall be implemented within a medium-termed period of 6 years, the chargeable part of the cost for discharge of the effluent (German law) range between 20 - 30% of the investment cost for the tertiary treatment stages.
Order a printed copy of manuscript 165_m2101 (click here: order) or download it as PDF-File (click here: download).
For design and operation of wastewater treatment plants for pulp and paper mill effluents rules were derived from the long-standing experience with such plants using different approaches. These are summarized here. Presented are the essential parameters for mainly used biological processes like anaerobic reactors, trickling filters, moving bed biofilm reactors, wastewater biofilters and activated sludge reactors. The consideration of these rules ensures treatment according the state of the art and at the same time according the requirements of the European Union to the application of best available technology (BAT). A chemical mechanical treatment will be sufficient only very rarely for a limited time.
New plants will be designed following these state of the art rules, using process combinations according to the type of production and resulting effluent.
Existing plants shall be checked according these rules. Whenever they do not meet the state of the art requirements, a renovation must be prepared. The instant of the execution then depends on different factors (requests, financing).
In order to adopt the state of the art for existing plants, the best possible variant of process combinations has to be chosen, regarding existing parts, predictable development of the effluent to be treated and of the authorities requirements and above all the local situation.
The inclination of the paper mill wastewaters for bulking sludge formation in activated sludge treatment has absolutely to be taken into account. Strategies, which are suitable to suppress this development, are mandatory required. Basis of most strategies is the activated sludge reactor as main part of the treatment chain. In case when this remains the only biological treatment step a selector or cascade system has to be developed. However, preferred is the use of an anaerobic or aerobic high load first stage. Finally an advanced treatment step has to be added when required. Examples from existing operational experience are reported. With advanced treatment an effluent quality for discharge surpassing BAT is reached.
In individual cases the biological cleaning is advantageously carried out with exclusive use of aerobic wastewater biofilters.
Order a printed copy of manuscript 167_m2105 (click here: order) or download it as PDF-File (click here: download).