operational and environmental consequences of large industrial cooling water systems

Operational and Environmental Consequences of Large Industrial Cooling Water Systems Sanjeevi Rajagopal ● Henk A. Jenner Vayalam P. Venugopalan Editors Operational and Environmental Consequences of Large Industrial Cooling Water Systems Editors Sanjeevi Rajagopal Department of Animal Ecology and Ecophysiology Institute for Water and Wetland Research Radboud University Nijmegen Nijmegen, The Netherlands s.rajagopal@science.ru.nl Vayalam P. Venugopalan Biofouling and Biofi lm Processes Section Water and Steam Chemistry Division BARC Facilities Kalpakkam, Tamil Nadu, India vpv@igcar.gov.in Henk A. Jenner Aquator BV Wageningen, The Netherlands jenner@aquator.nl ISBN 978-1-4614-1697-5 e-ISBN 978-1-4614-1698-2 DOI 10.1007/978-1-4614-1698-2 Springer New York Dordrecht Heidelberg London Library of Congress Control Number: 2011943882 © Springer Science+Business Media, LLC 2012 All rights reserved. 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Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) v Setting the scene and the need for integrated science for the operational and environmental consequences of large industrial cooling water systems Industries worldwide have long used and often even abused water: it is a necessary resource but, by their activities, they have affected the quality of that water and the health of organisms inhabiting it. In particular, its major use has been as cooling water required in large amounts by power generation, steel and iron, paper and pulp and oil industries. These industries abstract water from natural water bodies in very large amounts, often up to 75 cumecs (m 3 /s)—the fl ow rate of a moderately large river! The abstracted water often has to be treated with chemicals to combat opera- tional problems such as biofouling and corrosion. Moreover, the withdrawal and subsequent discharge of large amounts of water may produce signifi cant impacts on the receiving water body. Organisms, such as plankton, mobile invertebrates and fi nfi sh which may be of commercial importance, living in the discharge zone (the receiving waters) or taken in (impinged and entrained) with the cooling water are continuously subjected to a combination of mechanical, thermal and chemical stressors. There are many ways in which, foremost, human industries affect the natural aquatic systems and, second, by which the natural systems affect human industries. We can call the fi rst of these “operational problems”, i.e. the way in which the natu- ral aquatic system may hinder production by a plant, and the second “environmental problems” whereby the health of the system, in some way, has been reduced. For example, for the generation of power using oil, gas, coal or nuclear sources we have built power plants adjacent to water bodies where that water is used for direct cool- ing. Those power plants can be regarded as having a behaviour within their environ- mental systems and so that behaviour requires to be understood. In turn, the natural system also has a behaviour and so it is also important to understand that behaviour and the way it affects the natural system. Coupled with these is the need for a good scientifi c understanding of the ecology of the aquatic system, the hydrodynamics of the system, and the management and socio-economic system within which the power plant operates. The latter, therefore, includes the costs of tackling any problems Preface vi Preface caused on the plant by marine organisms (biofouling) and caused by the plant on the marine system. Hence, there is the need for a synthesis of the operational and envi- ronmental issues relating to industrial cooling water systems. The largest concerns for those involved in either production/operationally related or environmental-related problems concerning cooling water of these systems are, Fig. 1 Conceptual Models (Horrendograms) showing the environmental and operational aspects concerned with the exploration, construction and operation of coastal power plants (the acronyms used relate to the implementation of European Directives, see McLusky and Elliott 2004 for fur- ther details) vii Preface fi rst, impingement, defi ned as the trapping of larger material such as fi sh and mobile invertebrates before they get the chance to pass through the plant. Second, there is entrainment or the taking into the plant of smaller organisms and the creation of surfaces for the settlement of those smaller organisms and silts thus even creating a self-sustaining system within the plant. Third, there is the fate and effects of water and materials discharged from the plant, especially any thermal plume and its con- stituents. In addition to heat; we may even get scouring of the seabed adjacent to the discharge. We can summarise and communicate those aspects as a set of interlinked features in a “horrendogram”, i.e. a conceptual model showing all the aspects which need to be considered by operational and environmental managers concerned with industrial cooling water systems (Fig. 1 ). As mentioned above, biofouling inside cooling water systems is the result of the settlement of larval organisms on the surfaces inadvertently provided by the indus- trial plants. A power plant needs an adequate way of monitoring its surfaces not least because of the reduction in plant effi ciency or the need to determine if any antifouling measures have been successful. Hence the cooling water system has to be designed in relation to the magnitude of the fouling pressure and that design itself needs to minimise the fouling or produce an easier solution to the problem once it has occurred. There is a known sequence of fouling, whereby surfaces are prepared by slimes and micro-organisms, yeasts etc. which could both increase corrosion, so-called MIC (microbially infl uenced corrosion), and also makes them mimic normal settle- ment surfaces; in essence the industrial concrete and metal surfaces acting as a hard substratum similar to the rocky shore. There then follows a defi ned sequence of colonisation, with each organism having a preferred set of conditions. For example, barnacles prefer fast fl owing waters and thus clean surfaces with only a microbial slime layer, whereas mussels may prefer slower, more turbulent systems and so will colonise after other organisms have already settled. Hence, there is the need for a good understanding of the biology of the fouling organisms and the way in which antifouling measures can control each taxon. An intimate knowledge of the biology of the fouling organisms is required. For example barnacles require a neighbour to be adjacent because of their mode of reproduction involving internal fertilisation. Hence, there is the need to understand the fundamental issues and mechanisms of microbial fouling and corrosion and thus understand microbial as well as macrobial systems. The control of biofouling by chemical means, usually summarised as “chlorina- tion” and other control methods in industrial cooling water systems is a major issue for environmental and operational managers. The accepted means of controlling fouling is by adding biocides, very often oxidising (halogenated) compounds. These may be added as liquid (sodium hypochlorite), transported into the plant by lorries, or the chlorine may be produced on-site in specifi c Electro-Chlorination Plants (ECPs) where the biocide is generated by electrolysis of seawater prior to reinjec- tion. Hence, there is the need for a good understanding of chlorination chemistry and the resultant ecotoxicology of the marine cooling water systems (e.g. Taylor 2006 ). Once chlorination is in operation, then the production of organic halogenated viii Preface by-products, e.g. trihalomethanes, chloroform, bromoform, etc., in addition to the oxidising residuals can create environmental concerns in the receiving waters. Given the costs of biofouling treatment, yet again affecting the economic viability of the operation, power plants require technological and economically benefi cial solutions to biofouling and biocorrosion control as well as environmentally sustainable solu- tions. For example, by adjusting the timing and magnitude of chlorination, whether as a pulse or as continuous dosing, in relation to the peak times of settlement by fouling organisms, a more cost effective and optimal solution can be produced. The use of biocides is in itself a diffi cult environmental choice because of chlo- rinated by-product formation where some of the products are listed chemicals which may be prohibited for discharge. There is then the requirement for ecotoxicological assessments to determine the scale of those potential problems. Therefore, alterna- tive methods of cooling are often sought. A rather old-fashioned method is to heat up the intake/outlet conduits, by plant internal recirculation, where the design of the plant allows it for heating up the water, the so-called thermoshock method. New advanced technological methods include the use of “BioBullets” composed of a toxic compound coated with an attractive nutrient for bivalves on micro scale. In addition to the operational problems caused by entrainment, operational and environmental managers are required to address environmental concerns relating to the organisms entrained, by defi nition those suffi ciently small to get through the initial screens, often with a mesh of 1 cm 2 , and then into the body of the power plant. Hence, this includes the permanent members of the plankton, the holoplankton, and also the dispersing stages of marine organisms, the meroplankton including those of fi shes (the ichtyoplankton). While there may be billions of such organisms in the water column and their populations may be spatially and temporally variable, it is still necessary to detect whether the cooling water intake is having an effect. However, that inherent variability, what may be called noise in the system, makes it diffi cult to detect an effect, the signal within the so-called signal-noise ratio. Following its passage through condensers inside power plants, the discharge of the cooling water then has the potential for changing the characteristics of the receiving waters. As mentioned above, this may include the introduction of chlori- nated by-products but also, and most noticeably, raising the temperature and in which case those waters become suitable for colonisation by any organisms (invad- ers) adapted to the conditions. For example, the clam Corbicula uses outlet channels in winter time as refuge for surviving and, in Southampton Water (UK) a population of the invasive clam Mercenaria mercenaria has become established near a power plant discharge. Thus invasive species have implications for industrial cooling water systems, which provide changed conditions in the receiving waters, for example by raising the temperature, and then those waters become suitable for colonisation by any organisms which can tolerate the conditions. Invasive species such as the zebra mussel Dreissena polymorpha have become a nuisance by settling inside cooling water systems in large numbers. After passage through the industrial plant, the cooling water discharge often produces a thermal plume, in which the water may be 7–10°C higher than ambient. The characteristics and behaviour of that plume, for example, in either attracting ix Preface organisms or moving over areas of nature conservation importance, become causes for concern. Of course, if the plume is then entrained by the cooling water intake, then this is a production problem for the plant which can reduce its effi ciency. The resultant thermal plume may affect habitats depending on the thermal tolerances of the organisms and in cases where the receiving areas are of nature conservation importance then this could lead to breaching of environmental and conservation regulations. For example, many power plants are in estuaries which include large intertidal areas which support internationally important populations of wading birds and juvenile fi shes (McLusky and Elliott 2004 ). Any effects of the plume on either the invertebrate prey or predators of those sites thus become a cause for concern to be addressed by environmental and operational managers. For example, given that many organisms have temperature thresholds which determine times of spawning increases of temperature could lead to warm-water spawners breeding earlier and cold-water spawners delaying their reproduction. Perhaps the most high-profi le effect of power plants and that which attracts most adverse press coverage is fi sh impingement, the ability of the plant to suck in fi sh and mobile invertebrates (and weeds and garbage). Indeed this problem may reach such proportions that we can describe power plants as “stationary trawlers”! The extent of this depends on fi sh populations in the area, their migrations particularly onshore or for breeding and at times such as the winter when the power plant and its cooling system may be working at a maximum (Elliott and Hemingway 2002 ). In addition to this being a potential problem for the natural populations in the source water areas, this is also a production problem for the power plant as the impinged fi sh have to be either returned to the waters, often dead and thus creating both an organic discharge from the plant and public relations problem of having dead fi sh washed up near the plant, or disposed of to landfi ll, in itself a costly exercise given that the biological material is highly organic and thus has the potential to affect watercourses. In some countries, disposal to landfi ll is taxed and thus expensive for the power plant. Hence, there is the need to assess the technologies dealing with impingement and disposal of impinged material and for countries to learn from one another. As indicated above, there is the need to determine the behaviour of the power plant and any materials emanating from it within a context of the natural system. A knowledge of this behaviour will be required as a background to cooling water discharge guidelines in each country. Such guidelines may follow the “monitoring, modelling and management” framework—indeed, business would emphasise that you cannot manage a problem unless you can measure it and you cannot predict the effects of doing something unless you can model it. Recent advances in numerical modelling, such as through advanced 3D modelling are therefore important in this context. There is the need to use numerical modelling to determine the behaviour of the plume and thus the probability that it will affect certain areas around the plant and in the receiving waters. There is also the need to measure impingement and entrainment and, where possible, to model these as a way of providing predictive support to the designers and managers of cooling water systems. It is axiomatic that any human activity which has the potential to adversely affect the natural environment requires permissions. This lies within a legal and x Preface administrative framework, thus including discharge consents, permits, licences and authorisations and environmental assessments, and requires environmental protec- tion agencies, nature conservation bodies and ministries of the environment to enact and police these. Within political blocs such as the European Union, such laws and regulations may be at a local, regional, national and European level (including the Water Framework Directive, the Habitats and Species Directive and the Integrated Pollution Prevention and Control Directive, e.g. Apitz et al. 2006 ). Some of these are mirrored by the US Clean Water Act and corresponding legislation in many other countries. Countries are also obliged to follow international obligations such as the need to protect systems sustainably under the Convention for Biological Diversity or the UN Conference on Environment and Development. Of course these follow from the political will in any state to decide if the environmental conse- quences are suffi cient to outweigh the industrial and social advantages. This regula- tory and political context is what we may call environmental governance such that industries such as power plants operate within what is called a PEST environment, which includes the prevailing political, economic, societal and technological regime. Hence by taking together all of the above aspects, we can emphasise that we need sustainable solutions to the problems created by placing cooling water systems in natural environments. More importantly, as discussed above, those solutions are required to be sustainable and hence we take the view that for them to be sustainable they have to fulfi l “ the 7 - tenets ”—that our actions should be: Environmentally/ecologically sustainable • Technologically feasible • Economically viable • Socially desirable/tolerable • Legally permissible • Administratively achievable and • Politically expedient (Mee et al. • 2008 ) Each of these aspects requires good and adequate science upon which both oper- ational (production) management and environmental management can be based. The science has to be fi t-for-purpose, not least because it is expensive and also the consequences of unforeseen events may also be expensive. We need the science to prioritise our need for knowledge—to separate the “nice to know” from the “need to know” and to determine the cost-benefi t of the work (i.e. what “bang do we get for a buck”). We need to understand the sequence of understanding (now, mid, long term), our ability to do it (now, mid, long term) and the applicability of the knowl- edge (single- or multiple site specifi city). We need to be sure of our basic under- standing—do we have conceptual models leading to hypothesis generation and testing leading to what if? and so what? questions; what are the effects of power plants on marine/estuarine environment and vice versa; what is the impact on domi- nant processes, structure and functioning—understanding the reliance, resistance, recovery, hysteresis, etc. of natural systems; do these aspects affect the carrying capacity of systems—is the carrying capacity reduced for the biota and other human [...]... Each of these species has its own characteristics in terms of reproductive ecology, settlement behaviour and response to environmental changes Understanding of these aspects would be advantageous for those concerned with the operation and management of industrial cooling water systems 2 Biofouling in Cooling Water Intake Systems: Ecological Aspects 3 15 Biofouling in Industrial Cooling Water Systems. .. relating to biofouling, biofilms (ecology and biotechnology) and environmental effects of cooling water discharges He is currently heading the Biofouling and Biofilm Processes Section Since 1996, he is on the editorial boards of Aquatic Ecology (as Consulting Editor) and Water Research (as Associate Editor) Contents 1 Operational and Environmental Issues Relating to Industrial Cooling Water Systems: An... Wageningen, The Netherlands S Rajagopal et al (eds.), Operational and Environmental Consequences of Large Industrial Cooling Water Systems, DOI 10.1007/978-1-4614-1698-2_2, © Springer Science+Business Media, LLC 2012 13 14 S Rajagopal and H.A Jenner Uncontrolled growth of biofouling can make normal operation of a plant extremely difficult As just mentioned, the conditions inside the cooling water systems are ideally... accretion, consisting of such diversity of organisms as hydroids, polychaetes, barnacles, mussels, oysters and ascidians Though the number of species constituting a given biofouling community may be large, growth in industrial cooling systems tends to be dominated by just a handful of species (Venugopalan and Narasimhan 2008) (Fig 1.3) 3 Biofouling Biofouling in cooling water systems includes both... blockage, choking and corrosion Environmental effects result from the withdrawal and discharge of large quantity of water, which alter many of its chemical and biological characteristics It is seen that operational and environmental issues related to cooling water systems tend to get addressed separately, though in reality they are two sides of the same coin (Venugopalan and Narasimhan 2008) There is... comprehensive and integrated manner to ensure that utilities are able to solve the operational problems with least damage to the recipient water body Fig 1.6 Potential operational and environmental issues relating to the use of seawater for condenser cooling in power plants (Modified after Turnpenny and Coughlan 1992) 1 Operational and Environmental Issues Relating to Industrial Cooling Water 11 Acknowledgements... on the cooling- water intake screens of Britain’s largest direct-cooled power station Mar Pollut Bull 56:723–739 Israel S, Satheesh R, Venugopalan VP, Munuswamy N, Subramoniam T (2012) Impact of condenser discharge on intertidal fauna: sand crabs as indicator organisms In: Rajagopal S, Jenner HA, Venugopalan VP (eds) Operational and environmental consequences of large industrial cooling water systems. .. C M Bruijs and Colin J L Taylor 19 Cooling Water Discharge Guidelines in the Netherlands: Recent Developments Through Advanced 3D Modelling 411 Maarten C M Bruijs, Henk A Jenner, and Dju Bijstra 20 Regulatory Aspects of Choice and Operation of Large- Scale Cooling Systems in Europe 421 Andrew W H Turnpenny, Maarten C M Bruijs, Christian Wolter, and Neil Edwards 21 Cooling Water Systems: Efficiency... Lidita Khandeparker, and Chetan A Gaonkar 65 6 Microbial Fouling and Corrosion: Fundamentals and Mechanisms Toleti S Rao 95 7 Invasive Species: Implications for Industrial Cooling Water Systems 127 Sanjeevi Rajagopal and Gerard van der Velde 8 Chlorination and Biofouling Control in Industrial Cooling Water Systems 163 Sanjeevi Rajagopal 9 Chlorination Chemistry and Ecotoxicology... researcher, manager and later as senior consultant At KEMA, he initiated the research on micro- and macrofouling in cooling water systems of power generating and other large industries He is the co-editor of three books dealing with biofouling and has published more than 100 papers He was a principal of a governmental committee (CIW) developing a new and innovative directive for the discharge of heated effluents, . Operational and Environmental Consequences of Large Industrial Cooling Water Systems Sanjeevi Rajagopal ● Henk A. Jenner Vayalam P. Venugopalan Editors Operational and Environmental Consequences. Environmental Consequences of Large Industrial Cooling Water Systems Editors Sanjeevi Rajagopal Department of Animal Ecology and Ecophysiology Institute for Water and Wetland Research Radboud University. research on micro- and macrofouling in cooling water systems of power generating and other large industries. He is the co-editor of three books dealing with biofouling and has published more