- Email: [email protected]
Controlling Industrial Emissions—Practical Experience
64
CONFERENCE REPORTS
respect of Rhizomania controlÐ although it is the cheapest option. The next cheapest, in terms of both disposal cost and capital cost, was chemical stabilization, which was selected. Treatment with Rhenipal gives a stabilized sludge free of pathogens, suitable for land restoration and, if used as an engineering material in land® ll, it is exempt from land® ll tax. Martin Clark and Nina Sweet (Environment Agency), with an inspiringly titled paper `SludgeÐ getting rid of it’ , gave the Environment Agency’ s viewpoint on sludge treatment and disposal. Sludge issues include those from industrial processes, such as paper processing and tanneries, as well as sewage sludge. The EA has established a crossfunctional sludge group involving representatives from key functions of the EA, re¯ ecting the view that sludge and waste recycling and disposal cannot be dealt with in isolation and an integrated approach is vital. The most favoured option is waste reduction, followed by reuse, recovery, such as recycling, composting and energy generation, with disposal the least favoured, which corresponds to the principles of BATNEEC. The ® nal fate of sludge must be selected as the BPEO, and the EA has published a guidance note, TGN E1: BPEO Assessments for IPC, which includes a hazard assessment of wastes involving the calculation of a Final Hazard Score (FHS) for each option considered. The FHS considers the potential effects of a waste, based on its quantity and hazardousness, and is considered together with other environmental effects, such as releases to air and water, deposition to land from air, odours and cost. Where reuse of waste is not possible, the main routes are recovery (for example land spreading, incineration with energy recovery, inorganic components) and disposal (land® ll, specialized destruction or incineration without energy recovery). The proposed Land® ll Directive, if implemented, will severely restrict deposition of organic carbon, so that sludge will require pretreatment, for example by composting or incineration. It was concluded that the widest range of alternatives for sludge disposal must be identi® ed and evaluated at an early stage, with regular updating through the decision-making process. Steve Fairhurst (North-West Water Ltd) and Paul Venn (Bechtel Water Technology) gave a presentation on `The Mersey Valley Processing Centre’ for incineration and recycling of digested sludge. NWWL currently produces 127,000 tons/year of sludge dry solids, of which 33% is recycled to land, 18% to land® ll and 49% to sea, with the Mersey Valley area generating 97,000 tons/year of sludge solids. After evaluating 37 different combinations of treatment and disposal options for Mersey Valley sludge, six options were selected: liquid and cake to agriculture, cake to land® ll and reclamation and composted sludge to horticulture, with the majority as de-watered sludge cake to incineration. This is to be implemented in the Mersey Valley Processing Centre, comprising sludge reception and storage, sludge de-watering to cake, sludge cake export, sludge cake incineration and energy recovery and transfer of de-watering liquors to sewage treatment. Norman Weisz and Odd Egil Solheim (Cambi a/s, Billingstad, Norway) discussed `Thermal hydrolysis of sludge and organic waste’ . Although the advantages of thermal sludge conditioning are well established, it has not been widely adopted as a sludge treatment process. The problems addressed by Cambi are high-pressure pumping of
sludge, fouling of heat exchangers, wear on equipment, especially valves, high energy consumption and odour. Thermal hydrolysis is now being used at a treatment plant in Norway, as a pretreatment before anaerobic digestion, with a capacity of 18,000 tons/year of sludge containing 3600 tons/ year solids. The process achieves 93% reduction in sludge tonnage, after drying to 90% solids, with 57% of the COD converted to biogas. The cost was given as about £100/ton. Thermal hydrolysis is being tested on a pilot scale to generate an oxidizable substrate for denitri® cation from organic domestic waste, for which ethanol is currently in use. Controlling Industrial EmissionsÐ Practical Experience A two-day international symposium organized by the Institution of Chemical Engineers, co-sponsored by the Institution of Mechanical Engineers, the Institution of Energy, the Institute of Physics and the National Society for Clean Air, and held at the Commonwealth Institute, London, UK, 3± 4 November 1997 Report by Mike Nicholas (Lurgi (UK), Woking, and the University of Surrey, UK) Following a series of successful IChemE events on Desulphurization, Controlling Industrial Emissions considered in a wider context the key business and technology drivers governing the way in which the process industry responds to ever more demanding environmental pressures. In his opening address, Professor J.S. Harrison noted that with environmental issues high on the agenda, it is becoming increasingly important that industry must play an integral part in the policy-making process. The Rt Hon Michael Meacher, in the plenary presentation, ranked global warming as the most serious environmental effect facing the world today, and also noted the importance of air quality. He continued, stating that the Government will investigate environmental economic instruments, adding that there is a need to ® nd policy instruments which encourage innovation rather than caution. On the subject of innovation, he expects IChemE members to play a vital role in meeting environmental targets. With regard to the future of coal, he admitted that if all proposed EC directives were to apply the future looked bleak. He highlighted the promising role of clean coal technology but then stressed that the Government was working towards a diversi® ed energy strategy and was committed to an increase in the combined use of renewables and CHP to 25% by 2010. During the ® rst session, which focused on `The Challenge’, Herbert Aichinger (Head of DG XIÐ European Commission) described the EC Directive on Integrated Pollution Prevention and Control (IPPC) as a gateway to the next millennium. Whilst the Directive has been based on the UK’ s IPC regime it was stressed that IPPC has a wider scope covering emissions to air, water and land and in addition issues such as waste production/disposal, energy use, accidents and site contamination. It was stressed that the concept of Best Available Techniques (BAT) plays a central role in the Directive and that industry must get actively involved in current discussions concerning drafting of the Best Available Techniques Reference Documents (BREFs). David Fisk (DETR) continued the theme of industrial Trans IChemE, Vol 76, Part B, February 1998
CONFERENCE REPORTS involvement, re-emphasizing that the only way to move forward is through innovation. Moreover, the Government would seek to ensure that equal effort will be made by each industrial sector, thus achieving a levelling of the marginal costs of pollution control. It was also stressed that the Government is keen to explore measures such as quotas and permit trading, in the control of industrial pollution. Jan Vernon (KPMG) indicated that there are signi® cant market opportunities for companies which are aware of environmental concerns and develop services which address them. She then stated that the stage beyond compliance is the move towards sustainability. She highlighted ICI and Unilever who are taking the lead by adopting holistic or lifecycle methods to assess their overall environmental impacts. It was noted, however, that the regulators seem unable to adopt a similar approach. Adding weight to the progress towards sustainable development, Dariusz Prasek stated that the European Bank for Reconstruction and Development attached particular importance to operations which promote energy and resource ef® ciency, waste reduction, resource recovery and recycling, the use of `clean technologies’ and the promotion of renewable resources. Following the stimulating coverage of the current challenges faced by industry, the responses to date were covered in a number of sessions. In the pre-treatment session Les White (Esso Petroleum) examined the importance of a rational approach to tackling the underlying concerns. The problems caused by a single issue focus need to be recognized along with the need to seek solutions with the least societal cost. In¯ uencing societal behaviour will be a major focus of the European Commission’ s second AutoOil Programme. The second paper in the pre-treatment session, presented by John Morris (Consultant Engineer and Associate Lecturer, Birmingham University) highlighted advances in coal preparation techniques and their potential when used in conjunction with other pollution abatement technology. The paper by Collins and Massey (National Power) highlighted that major emission reductions had been achieved, mainly due to the substantial programme of replacing older coal ® red plant with combined cycle gas turbine (CCGT) technology and a diversi® cation to wind and CHP projects. He then indicated that adopting Environmental Management Systems (EMSs) was at the heart of meeting the challenge. The experience gained by National Power has shown that adopting an EMS has given both environmental improvement and ® nancial savings. ICI’ s site at Runcorn was used by Chris Haigh as an example of the rapid pace of change resulting in an almost debilitating peak of emission control expenditure by the bulk chemicals industry. ICI has seen a culture change around the way emissions are viewed and dealt with which goes to the heart of all operations. To meet the increasing environmental demands process industries will, in the future, focus on Responsible Care initiatives, advances in data handling and de® ning the real concepts of sustainable development relating to a mature commodity business. Over the past few years the manufacturing industries have made great steps towards sustainable practices. Laurie Evans highlighted that Environmental Management Systems have been implemented on all Blue Circle’ s UK cement plants. On top of achieving drastic reductions in emissions Trans IChemE, Vol 76, Part B, February 1998
65
through the adoption of both clean-up and clean technologies, examples of which were discussed at length, Blue Circle has committed itself to a proactive environmentalpolicy including continuous improvement of environmental performance and contribution to long term economic, environmental and social sustainability. Robin McIntosh (Pilkington Glass) focused on French and Italian emissions legislation to demonstrate the signi® cant changes in the way which pollution control within the glass industry has been viewed. Through taking an holistic approach, authorities in these European countries have concluded that ® tting end-of-pipe acid gas and particulate abatement equipment would, when considering the additional sorbent utilization/disposal and energy requirements, do more harm than good to the environment as a whole. McIntosh also suggested that emissions of NOx exceed the combined total of all other pollutants so that the greatest environmental bene® t will be gained from NOx reduction technology combined with waste heat recovery, instead of acid gas and particulate removal. Eric Hutton (British Steel) presented the moves towards sustainable development made by the steel industry. As an example he referred to the lightweighting of automobile body parts, which delivers environmental bene® ts not only through the reduction of quantities in construction materials required but also in improved economy throughout the vehicle lifetime. This example demonstrated the necessity to give due recognition to overall life-cycle implications. The advanced combustion session comprised three papers from ABB Carbon, Shell International Oil Products and British Coal Corporation. In addition to explaining developments in the various gasi® cation based technology, the presenters stated that the main market area is in the Far East where imported coal needs to be utilized with the highest achievable ef® ciencies. With regard to global warming potential, clean coal technologies can give typically 15% reductions due to the increased energy ef® ciency compared with conventional coal technology. The penultimate session focused on recycling and energy from waste. Josef Diestelkemper discussed the developments in emissions control technology for Lurgi’ s waste to energy plants, now capable of bettering the tightest of EC emission limits. He stated that the construction of thermal waste disposal plants is a necessity since the land® lling of untreated waste with the known consequences of land availability and uncontrolled releases cannot be tolerated in the long run. He concluded that a fair comparison between different ¯ ue gas cleaning processes can only be made if the costs resulting from operation, for example land® ll costs, are included in the estimate as well as risk calculations with regard to future developments. Michael Lewis (PowerGen) discussed the wastes or byproducts from power generation and the initiatives made to introduce and improve by-product utilization. He highlighted the numerous opportunities available and said that UK experience has shown that effective marketing can signi® cantly increase the reuse of power generation byproducts. However, whilst waste minimization and reuse are vital for environmental sustainable development, one obstacle remains; that of adverse public opinion to the reuse of such wastes. David Slater (Environment Agency) gave the ® nal presentation which looked at the development and future
66
CONFERENCE REPORTS
of the regulating authorities. He noted that, just as this conference had diversi® ed from the theme of desulphurization, so too has pollution control developed from control of stack heights, through ¯ ue gas desulphurization into what is now a very diverse ® eld. So, what next? He envisaged a different role for the Environment Agency, moving away from manager of pollution control, through auditor to holder of the ring. As for industry, liability and image will become essential with companies reporting in a transparent and accountable way, becoming aware of their own impacts on the environment and the public’ s perception of these. He was also keen to promote the formation of partnerships, with large companies sharing their experiences with smaller ones. In his words, common solutions for common problems. He then outlined that over the next few years, in addition to global warming, health will be of major importance with the focus moving to diffuse sources and
chronic effects. With respect to speci® c emission limits his views were clear. BATNEEC drives towards tighter limits. We are on a ratchet, you can never go back. Controlling Industrial Emissions has highlighted that through the adoption of Environmental Management Systems, the development and implementation of cleaner technologies and the trend for a more holistic, life-cycle perspective, the process and manufacturing industries are leading the way in environmental practices, moving towards sustainability. For information on purchasing `Controlling Industrial EmissionsÐ Practical Experience’ (IChemE Symposium Series No. 143) please contact Book Sales, Institution of Chemical Engineers, Davis Building, 165-189 Railway Terrace, Rugby CV21 3HQ, UK (Tel: + 44 1788 578214, Fax: +44 1788 560833).
Trans IChemE, Vol 76, Part B, February 1998
CONFERENCE REPORTS
respect of Rhizomania controlÐ although it is the cheapest option. The next cheapest, in terms of both disposal cost and capital cost, was chemical stabilization, which was selected. Treatment with Rhenipal gives a stabilized sludge free of pathogens, suitable for land restoration and, if used as an engineering material in land® ll, it is exempt from land® ll tax. Martin Clark and Nina Sweet (Environment Agency), with an inspiringly titled paper `SludgeÐ getting rid of it’ , gave the Environment Agency’ s viewpoint on sludge treatment and disposal. Sludge issues include those from industrial processes, such as paper processing and tanneries, as well as sewage sludge. The EA has established a crossfunctional sludge group involving representatives from key functions of the EA, re¯ ecting the view that sludge and waste recycling and disposal cannot be dealt with in isolation and an integrated approach is vital. The most favoured option is waste reduction, followed by reuse, recovery, such as recycling, composting and energy generation, with disposal the least favoured, which corresponds to the principles of BATNEEC. The ® nal fate of sludge must be selected as the BPEO, and the EA has published a guidance note, TGN E1: BPEO Assessments for IPC, which includes a hazard assessment of wastes involving the calculation of a Final Hazard Score (FHS) for each option considered. The FHS considers the potential effects of a waste, based on its quantity and hazardousness, and is considered together with other environmental effects, such as releases to air and water, deposition to land from air, odours and cost. Where reuse of waste is not possible, the main routes are recovery (for example land spreading, incineration with energy recovery, inorganic components) and disposal (land® ll, specialized destruction or incineration without energy recovery). The proposed Land® ll Directive, if implemented, will severely restrict deposition of organic carbon, so that sludge will require pretreatment, for example by composting or incineration. It was concluded that the widest range of alternatives for sludge disposal must be identi® ed and evaluated at an early stage, with regular updating through the decision-making process. Steve Fairhurst (North-West Water Ltd) and Paul Venn (Bechtel Water Technology) gave a presentation on `The Mersey Valley Processing Centre’ for incineration and recycling of digested sludge. NWWL currently produces 127,000 tons/year of sludge dry solids, of which 33% is recycled to land, 18% to land® ll and 49% to sea, with the Mersey Valley area generating 97,000 tons/year of sludge solids. After evaluating 37 different combinations of treatment and disposal options for Mersey Valley sludge, six options were selected: liquid and cake to agriculture, cake to land® ll and reclamation and composted sludge to horticulture, with the majority as de-watered sludge cake to incineration. This is to be implemented in the Mersey Valley Processing Centre, comprising sludge reception and storage, sludge de-watering to cake, sludge cake export, sludge cake incineration and energy recovery and transfer of de-watering liquors to sewage treatment. Norman Weisz and Odd Egil Solheim (Cambi a/s, Billingstad, Norway) discussed `Thermal hydrolysis of sludge and organic waste’ . Although the advantages of thermal sludge conditioning are well established, it has not been widely adopted as a sludge treatment process. The problems addressed by Cambi are high-pressure pumping of
sludge, fouling of heat exchangers, wear on equipment, especially valves, high energy consumption and odour. Thermal hydrolysis is now being used at a treatment plant in Norway, as a pretreatment before anaerobic digestion, with a capacity of 18,000 tons/year of sludge containing 3600 tons/ year solids. The process achieves 93% reduction in sludge tonnage, after drying to 90% solids, with 57% of the COD converted to biogas. The cost was given as about £100/ton. Thermal hydrolysis is being tested on a pilot scale to generate an oxidizable substrate for denitri® cation from organic domestic waste, for which ethanol is currently in use. Controlling Industrial EmissionsÐ Practical Experience A two-day international symposium organized by the Institution of Chemical Engineers, co-sponsored by the Institution of Mechanical Engineers, the Institution of Energy, the Institute of Physics and the National Society for Clean Air, and held at the Commonwealth Institute, London, UK, 3± 4 November 1997 Report by Mike Nicholas (Lurgi (UK), Woking, and the University of Surrey, UK) Following a series of successful IChemE events on Desulphurization, Controlling Industrial Emissions considered in a wider context the key business and technology drivers governing the way in which the process industry responds to ever more demanding environmental pressures. In his opening address, Professor J.S. Harrison noted that with environmental issues high on the agenda, it is becoming increasingly important that industry must play an integral part in the policy-making process. The Rt Hon Michael Meacher, in the plenary presentation, ranked global warming as the most serious environmental effect facing the world today, and also noted the importance of air quality. He continued, stating that the Government will investigate environmental economic instruments, adding that there is a need to ® nd policy instruments which encourage innovation rather than caution. On the subject of innovation, he expects IChemE members to play a vital role in meeting environmental targets. With regard to the future of coal, he admitted that if all proposed EC directives were to apply the future looked bleak. He highlighted the promising role of clean coal technology but then stressed that the Government was working towards a diversi® ed energy strategy and was committed to an increase in the combined use of renewables and CHP to 25% by 2010. During the ® rst session, which focused on `The Challenge’, Herbert Aichinger (Head of DG XIÐ European Commission) described the EC Directive on Integrated Pollution Prevention and Control (IPPC) as a gateway to the next millennium. Whilst the Directive has been based on the UK’ s IPC regime it was stressed that IPPC has a wider scope covering emissions to air, water and land and in addition issues such as waste production/disposal, energy use, accidents and site contamination. It was stressed that the concept of Best Available Techniques (BAT) plays a central role in the Directive and that industry must get actively involved in current discussions concerning drafting of the Best Available Techniques Reference Documents (BREFs). David Fisk (DETR) continued the theme of industrial Trans IChemE, Vol 76, Part B, February 1998
CONFERENCE REPORTS involvement, re-emphasizing that the only way to move forward is through innovation. Moreover, the Government would seek to ensure that equal effort will be made by each industrial sector, thus achieving a levelling of the marginal costs of pollution control. It was also stressed that the Government is keen to explore measures such as quotas and permit trading, in the control of industrial pollution. Jan Vernon (KPMG) indicated that there are signi® cant market opportunities for companies which are aware of environmental concerns and develop services which address them. She then stated that the stage beyond compliance is the move towards sustainability. She highlighted ICI and Unilever who are taking the lead by adopting holistic or lifecycle methods to assess their overall environmental impacts. It was noted, however, that the regulators seem unable to adopt a similar approach. Adding weight to the progress towards sustainable development, Dariusz Prasek stated that the European Bank for Reconstruction and Development attached particular importance to operations which promote energy and resource ef® ciency, waste reduction, resource recovery and recycling, the use of `clean technologies’ and the promotion of renewable resources. Following the stimulating coverage of the current challenges faced by industry, the responses to date were covered in a number of sessions. In the pre-treatment session Les White (Esso Petroleum) examined the importance of a rational approach to tackling the underlying concerns. The problems caused by a single issue focus need to be recognized along with the need to seek solutions with the least societal cost. In¯ uencing societal behaviour will be a major focus of the European Commission’ s second AutoOil Programme. The second paper in the pre-treatment session, presented by John Morris (Consultant Engineer and Associate Lecturer, Birmingham University) highlighted advances in coal preparation techniques and their potential when used in conjunction with other pollution abatement technology. The paper by Collins and Massey (National Power) highlighted that major emission reductions had been achieved, mainly due to the substantial programme of replacing older coal ® red plant with combined cycle gas turbine (CCGT) technology and a diversi® cation to wind and CHP projects. He then indicated that adopting Environmental Management Systems (EMSs) was at the heart of meeting the challenge. The experience gained by National Power has shown that adopting an EMS has given both environmental improvement and ® nancial savings. ICI’ s site at Runcorn was used by Chris Haigh as an example of the rapid pace of change resulting in an almost debilitating peak of emission control expenditure by the bulk chemicals industry. ICI has seen a culture change around the way emissions are viewed and dealt with which goes to the heart of all operations. To meet the increasing environmental demands process industries will, in the future, focus on Responsible Care initiatives, advances in data handling and de® ning the real concepts of sustainable development relating to a mature commodity business. Over the past few years the manufacturing industries have made great steps towards sustainable practices. Laurie Evans highlighted that Environmental Management Systems have been implemented on all Blue Circle’ s UK cement plants. On top of achieving drastic reductions in emissions Trans IChemE, Vol 76, Part B, February 1998
65
through the adoption of both clean-up and clean technologies, examples of which were discussed at length, Blue Circle has committed itself to a proactive environmentalpolicy including continuous improvement of environmental performance and contribution to long term economic, environmental and social sustainability. Robin McIntosh (Pilkington Glass) focused on French and Italian emissions legislation to demonstrate the signi® cant changes in the way which pollution control within the glass industry has been viewed. Through taking an holistic approach, authorities in these European countries have concluded that ® tting end-of-pipe acid gas and particulate abatement equipment would, when considering the additional sorbent utilization/disposal and energy requirements, do more harm than good to the environment as a whole. McIntosh also suggested that emissions of NOx exceed the combined total of all other pollutants so that the greatest environmental bene® t will be gained from NOx reduction technology combined with waste heat recovery, instead of acid gas and particulate removal. Eric Hutton (British Steel) presented the moves towards sustainable development made by the steel industry. As an example he referred to the lightweighting of automobile body parts, which delivers environmental bene® ts not only through the reduction of quantities in construction materials required but also in improved economy throughout the vehicle lifetime. This example demonstrated the necessity to give due recognition to overall life-cycle implications. The advanced combustion session comprised three papers from ABB Carbon, Shell International Oil Products and British Coal Corporation. In addition to explaining developments in the various gasi® cation based technology, the presenters stated that the main market area is in the Far East where imported coal needs to be utilized with the highest achievable ef® ciencies. With regard to global warming potential, clean coal technologies can give typically 15% reductions due to the increased energy ef® ciency compared with conventional coal technology. The penultimate session focused on recycling and energy from waste. Josef Diestelkemper discussed the developments in emissions control technology for Lurgi’ s waste to energy plants, now capable of bettering the tightest of EC emission limits. He stated that the construction of thermal waste disposal plants is a necessity since the land® lling of untreated waste with the known consequences of land availability and uncontrolled releases cannot be tolerated in the long run. He concluded that a fair comparison between different ¯ ue gas cleaning processes can only be made if the costs resulting from operation, for example land® ll costs, are included in the estimate as well as risk calculations with regard to future developments. Michael Lewis (PowerGen) discussed the wastes or byproducts from power generation and the initiatives made to introduce and improve by-product utilization. He highlighted the numerous opportunities available and said that UK experience has shown that effective marketing can signi® cantly increase the reuse of power generation byproducts. However, whilst waste minimization and reuse are vital for environmental sustainable development, one obstacle remains; that of adverse public opinion to the reuse of such wastes. David Slater (Environment Agency) gave the ® nal presentation which looked at the development and future
66
CONFERENCE REPORTS
of the regulating authorities. He noted that, just as this conference had diversi® ed from the theme of desulphurization, so too has pollution control developed from control of stack heights, through ¯ ue gas desulphurization into what is now a very diverse ® eld. So, what next? He envisaged a different role for the Environment Agency, moving away from manager of pollution control, through auditor to holder of the ring. As for industry, liability and image will become essential with companies reporting in a transparent and accountable way, becoming aware of their own impacts on the environment and the public’ s perception of these. He was also keen to promote the formation of partnerships, with large companies sharing their experiences with smaller ones. In his words, common solutions for common problems. He then outlined that over the next few years, in addition to global warming, health will be of major importance with the focus moving to diffuse sources and
chronic effects. With respect to speci® c emission limits his views were clear. BATNEEC drives towards tighter limits. We are on a ratchet, you can never go back. Controlling Industrial Emissions has highlighted that through the adoption of Environmental Management Systems, the development and implementation of cleaner technologies and the trend for a more holistic, life-cycle perspective, the process and manufacturing industries are leading the way in environmental practices, moving towards sustainability. For information on purchasing `Controlling Industrial EmissionsÐ Practical Experience’ (IChemE Symposium Series No. 143) please contact Book Sales, Institution of Chemical Engineers, Davis Building, 165-189 Railway Terrace, Rugby CV21 3HQ, UK (Tel: + 44 1788 578214, Fax: +44 1788 560833).
Trans IChemE, Vol 76, Part B, February 1998