Safety at Work 6 E Part 16 ppsx

Managing chemicals safely 875 operation together with electromechanical control systems Where the control equipment incorporates computers additional studies are needed A HAZOP study requires a multi-disciplinary approach by a team made up of technical specialists, i.e chemical engineer, chemist, production manager, instrumentation engineer, safety adviser etc It is coordinated by a leader who guides the systematic investigation into the effect of various faults that could occur The success of this study relies heavily on the quality of the leader and the positive and constructive attitude of the team members It is essential that the team have all the basic data plus line diagrams, flow charts etc., and understand how a HAZOP study works The HAZOP study breaks the flow diagram down into a series of discrete units Various failure and fault conditions are then considered using a series of ‘guide words’ to structure the investigation of the various circumstances that could give rise to those faults Each deviation for each guide word is considered in detail and team members are encouraged to think laterally and to ask questions especially about the potential for causing a fault condition Table 4.7.1 shows how each of the guide words can be interpreted to highlight possible deviations from normal operation and Figure 4.7.5 shows a HAZOP report form that could be used to record the findings of the study In the example in Table 4.7.1, under the first guide word, ‘None’, we could ask: ᭹ ᭹ ᭹ ᭹ ᭹ What could cause no flow? How could the situation arise? What are the consequences of the no-flow situation? Are the consequences identified hazardous or they prevent efficient operation? If so, can we prevent no-flow (or protect against the consequences) by changing the design or method of operation Table 4.7.1 Showing typical interpretations of HAZOP guide words Guide word Deviations None No forward flow, no flow, reverse flow More of Higher flow than design, higher temperature, pressure or viscosity etc Less of Lower flow than design, lower temperature, pressure or viscosity etc Part of Change in composition, change in ratio of components, component missing More than More components present in the system, extra phase, impurities present (air, water, solids, corrosion products) Other than What else can happen that is not part of the normal reaction, start-up or shutdown problems, maintenance concerns, catalyst change etc 876 Safety at Work HAZARD AND OPERABILITY STUDY Date of Study / / Sheet of Study title Study team Prepared by Project number Line diagram number sheets Procedure number Step Number/ Guide Word Deviation Cause Figure 4.7.5 Report from a HAZOP Study Consequence Action Managing chemicals safely ᭹ 877 If so, does the size of the hazard (i.e severity of the consequences multiplied by the probability of the occurrence) justify the extra expense? Similar questions are applied to each the other guide words, and so on Each time a component is studied the drawing or diagram should be marked Not until all components have been studied can the HAZOP study be considered complete Where errors occur on the drawing or more informations needed the drawing should be marked (using a different colour) and the points noted in the report To be effective the team needs to think laterally and there should be no criticism of other team members’ questions A strange or oblique question may spark off a train of investigation which could lead to the identification of potentially serious fault conditions A well-conducted HAZOP study should eliminate 80–85% of the major hazards, thereby reducing the level of risk in the plant In safety critical plant another HAZOP study, carried out when the detailed design has been finalised, could increase the probability of safe operations When the HAZOP study has been completed the necessary remedial actions should be agreed for implementation by the project or process manager Records of the changes in the design should be kept and checks made to ensure that the modifications have been carried out during the construction of the plant With plant that is controlled by computer, the HAZOP study needs to include consideration of the effects of aberrant computer behaviour and the team carrying out the study may need to be reinforced by the software designer plus an independent software engineer able to question the philosophy of the installed software program A technique known as CHAZOP has been developed for such plant which also highlights the safety critical control items 4.7.9.3 Plant control systems Many small, simple, and relatively low hazard plants are fully manually operated However, with more complex plant automated controls using electronic control systems are employed This does not necessarily make it safe since faults can, unknowingly, be built into the controlling software To achieve optimum levels of safe operation, computer software for plant control systems should be devised jointly by the software specialist and the production staff All operational requirements must be covered to ensure that the software designer does not make assumptions which could result in faulty or even dangerous operation of the plant The software must be designed to accommodate plant failures and any testing or checking necessary during or following maintenance Before installing it, the computer program must be challenged in all possible situations to ensure that it matches operational requirements Any review of software should include an independent software engineer who can challenge the philosophy behind the software All software 878 Safety at Work changes must be fully described and recorded and plant operators fully trained in the effects of the changes When automated computer control systems are incorporated into a plant, operators tend to rely on them completely to the extent that there is a risk that they forget how to control the plant manually This can be critical in an emergency and it may be prudent to switch the computer off occasionally, and, under supervised conditions, ensure that the operators are still able to control the plant manually Control panels should not be provided with too many instruments since this can confuse the operator and prove counterproductive However, sufficient instrumentation is needed to enable the operators to know what is going on inside closed vessels, pipes, pumps etc Critical alarms should be set into separate parts of control panel to highlight their importance This will reduce the potential for their being confused with others, and possibly overlooked The tone of audible critical alarms should be different from that of process alarm systems to prevent confusion Computer-controlled plant will frequently have three levels of operational and safety control: Level 1: Will mostly focus on process control of the plant and give indicative warnings of possible safety concerns when, for example, a rapid temperature rise may trigger a warning panel indicator Level 2: Control occurs when computer software initiates changes to control reaction kinetics If a reaction temperature continues to rise, the software would initiate the application of cooling water to the vessel to regain control and continue production Level 3: Is entirely a safety system when the process is out of control It will rely on hard-wired trips that shut the plant down safely and abandon production The hard-wired trips work independently of the computer system There is no universal formula for control systems and a control strategy must be developed for each plant based on the operating parameters A small batch plant consisting of two chemical reactors having a mixture of manual and automatic controls is shown in Figure 4.7.6 4.7.9.4 Assessment of risk in existing plants A review of existing chemical facilities should be undertaken to identify possible faults and so avoid acute and/or catastrophic loss The assessment should focus on ‘instantaneous failure prevention’ of plant such as: ᭹ ᭹ ᭹ ᭹ bulk oil or chemical storage facilities multi-chemical 200 litre drum store (especially if large-scale dispensing is carried out) chemical processes or mixing facilities solvent recovery plant Figure 4.7.6 Two chemical reactors having manual and automatic controls (Courtesy Rhone-Poulenc-Rorer) ˆ 880 ᭹ Safety at Work pipelines and pipework that contain oils or chemicals in quantity and/ or under pressure This review will identify those systems or processes that require a further detailed study which can be carried out using one or more of the techniques described below The end result of the assessment should be a position statement which describes the level of risk from the plant and identifies which facilities require additional measures to ensure they remain both physically and environmentally safe A number of techniques have been developed to identify the hazards and to assess the risks from plant and equipment These techniques range from the relatively simple to the highly complex A number are described in a BS EN standard50 Whichever technique is used it should be appropriate to the complexity of the plant and the materials involved 4.7.9.4.1 Simpler techniques The simpler techniques are aimed primarily at determining a ranking order of the risks from the chemical processes carried out in the area They should clarify which facilities create insignificant risks and require no further action The position statement for these facilities should record the reasons for this decision The simpler techniques include: The ‘What-if method’ is the simplest method to assess chemical process safety risks and is based on questions such as ‘What if the mechanical or electrical integrity of the process, the control systems and work procedures all fail, what consequences could arise in the worst case?’ While the potential consequences are largely determined by the inherent hazard of the material and the quantity involved, the reviewer is focused on safety concerns, e.g those arising from fire, explosion, toxic gas release, and environmental protection The ‘Checklist method’ is a structured approach whereby the reviewer responds to a predetermined list of questions This method is less flexible than the ‘What-if method’ and its effectiveness relies on the strengths and weaknesses of a predetermined checklist Examples of checklists can be found in chemical process safety literature The ‘Dow-Mond Index’ is a more structured approach than the previous two techniques and takes into account quantities and hazards to arrive at a basic risk classification This method provides a level of quantification of risk and considers the ‘off-setting’ factors which exist to control intrinsic hazards 4.7.9.4.2 More complex techniques Where the ranking process, described above, identifies facilities that warrant an assessment in greater depth, one of the techniques described below should be used: HAZOP study (see section 4.7.9.2.1) Failure modes and effects analysis (FMEA) FMEA is an inductive method for evaluating the frequency and consequence of failures It Managing chemicals safely 881 involves examining every component and considering all types of failure for each It can indicate generic components that may have a propensity to fail Fault tree analysis (FTA)51 FTA is a deductive method which starts by considering a particular fault or ‘top event’ and works backwards to form a tree of all the events and circumstances that could lead to the happening of that top event By assessing the probability of each individual event, an estimate of the probability of the top event occurring can be obtained If that probability is unacceptable the major components contributing to it can easily be identified and a costeffective replacement of them implemented This method lends itself to assessing the impact of changes in the system and has been useful in determining the causes of accidents 4.7.9.5 Functional safety life cycle management (FSLCM)52 FSLCM is a new technique designed to enable plant safety systems to be managed in a structured way The technique has been designed to accommodate computer-controlled plants from start-up to shutdown, including emergency shutdowns It aims to ensure that the safety related systems which protect and control equipment and plant are specified, engineered and operated to standards appropriate to the risks involved The key concepts of this technique are: (a) The safety life cycle – begins with a clear definition of the equipment and processes for which functional safety is sought and by a series of phases provides a logical path through commissioning, operation to final decommissioning (b) Safety management – sets a checklist for the things that need to be in place in order to prepare for and manage each phase of the safety life cycle These are incorporated into a formal safety plan (c) Design of safety related systems – puts the design of safety related control and protective systems into the overall context of the safe operation of equipment or facilities It requires that such systems are designed to meet specific risk criteria (d) Competencies – provides guidance on the appropriate skills and knowledge required by those people who will be involved in the technique By following a structured life cycle approach the hazards inherent in the operation of equipment or processes can be clearly identified The standards to which protection is provided can be demonstrated in an objective and constructive way 4.7.10 Further safety studies Having carried out a HAZOP study on the plant and incorporated its findings into the design, it is prudent to carry out a further review during 882 Safety at Work the commissioning period to check that the design modifications have produced the desired results This is necessary since the final details of the physical installation are often left to the installing engineers to decide and these could produce unforeseen hazards Finally, once the plant is commissioned and operational there should be routine safety checks carried out on a regular basis 4.7.11 Plant modifications Plant modifications, even apparently simple ones, can have major consequential effects15 It is crucial that the plant is not modified without proper authorisation and, for safety critical parts, the completion of a HAZOP study of the possible effects of the proposed changes A ‘process change form’ should be used which should include the reasons for the change Use of such a form also ensures a degree of control on the modifications made, especially if it has to be sanctioned by a senior technical specialist such as a process engineer, safety adviser, production manager and maintenance manager There needs to be clear guidance as to when the process change form has to be used so that there can be no misunderstanding After the plant has been modified it may be necessary to retrain the operators in the changed operation techniques 4.7.12 Safe systems of work Since human beings are necessary in the operation of chemical plants there is always the likelihood of errors being made that could result in hazards It is, therefore, important that operators are trained in the safe way to run the plant Such training, based on safe systems of work, should include the carrying out of risk assessments Errors in operation and misunderstandings can be reduced if the system of work is in writing 4.7.12.1 Instruction documentation There should be detailed written operating instructions for every chemical plant which can conveniently be considered in three parts: Operator’s instructions that give specific instructions on how to operate the plant and handle the materials safely The instructions should contain information on the process, quantities and types of materials used, and any special instructions for dealing with spillages, leaks, emergencies and first aid The instructions should also contain information on the expected temperatures, pressures and conditions, and provide information on the actions to be taken if they are exceeded, the type of PPE to be worn, a copy of the safety data sheet for each of the materials involved, techniques for taking samples and cleaning instructions Managing chemicals safely 883 Manufacturing procedures aimed at the operators and the supervisor in charge of the plant should explain the process and provide a synopsis of the chemical process undertaken The procedure should refer to likely problems such as exotherms and give details of actions to take The sequence of operations, quantities of materials used, temperature and pressure ranges, methods for dealing with spillages and leaks, disposal of waste, etc., should be included A process dossier should be compiled containing detailed information about the process, the plant and equipment design specifications and the basis of safety for the process This document should be a major reference source for the process engineer and be consulted and updated whenever a change is made 4.7.12.2 Training Both operators and supervision should be trained in the techniques for operating the plant, the process, materials used, their hazards and precautions to be taken, emergency procedures and first aid The training can be based on the content of the Operator Instructions and the Manufacturing Procedures and should include a study of the safety data sheets The importance of following the safe methods of work and the reporting of any deviations from the stated operating parameters should be emphasised Staff should be made aware of the potential hazards that could be encountered in the process if mistakes were made For example, what could happen if: ᭹ ᭹ ᭹ ᭹ ᭹ Equipment was not bonded to earth and a fire started Another chemical was mistakenly added The agitator had been stopped and restarted when it should have been on all the time The reaction was allowed to get too hot and an exothermal reaction took place The reaction got out of control and pressure developed resulting in a two-phase emission It is important that the operating staff are regularly re-trained in the operating instructions and that they are briefed on any changes made 4.7.12.3 Permits-to-work Permits-to-work are required where the work to be carried out is sufficiently hazardous to demand strict control over both access and the work itself This can occur when maintenance and non-routine work is being carried out in a chemical plant or for any normal operation where the risks faced make clear and unequivocal instructions necessary for the safety of the operators 884 Safety at Work The essential elements of a permit to work are: (a) The work to be carried out is described in detail and understood by both the operators of the plant and those carrying out the work (b) A full explanation is given to those carrying out the work of the hazards involved and the precautions to be taken (c) The area in which the work is to be carried out is clearly identified, made as safe as possible and any residual hazards highlighted (d) A competent, responsible and authorised person should specify the safety measures, such as electrical isolation, pipes blanked off etc to be taken on the plant, check that they have been implemented and sign a document confirming this and that it is safe for workmen to enter the area (e) The individual workmen or supervisor in charge must sign the permit to say they fully understand the work to be done, restrictions on access, the hazards involved and the precautions to be taken (f) The permit must specify any monitoring to be carried out before, during and after the work and require the recording of the results (g) When the work is complete, the workmen or supervisor must sign the permit to confirm that the work is complete and it is safe to return the plant to operations (h) A competent, responsible and authorised person must sign the permit, cancelling it and releasing the plant back to operations The format of a permit to work will be determined by the type of work involved but a typical permit is shown in Figure 4.7.7 Typical work requiring a permit to work includes hot work, entry into confined spaces, excavations, high voltage electrical work, work involving toxic and hazardous chemicals etc For a permit to work to be effective it is essential that all those involved understand the system, the procedure and the importance of following the laid down procedure Before the work starts all those concerned should be trained in the system and their individual responsibilities emphasised 4.7.13 Laboratories The use of chemicals in laboratories poses totally different problems from those met in a production facility The scale is much smaller, the equipment generally more fragile and, while the standard of containment for bench work is often less, the skill and knowledge of those performing the reactions are very high Work in quality control laboratories is normally repetitive using closely defined analytical methods Research laboratories are far wider in the scope of the reactions they investigate, sometimes dealing with unknown hazards, and in the equipment they use The principal hazards met in laboratories are fire, explosion, corrosion, and toxic attacks A limit should be specified for the total amount of flammables allowed in a laboratory at any one time, which should be enough for the day’s work but not exceed 50 litres 920 Safety at Work means to spur their contractors to become registered under ISO 14001 or EMAS The standards are designed to integrate with the established quality system and are compatible with safety management systems The key element that makes them effective in addressing the environmental issues is the need for continuous improvement coupled with an Aspects and Impacts Analysis This means that no matter how good an organisation is, if it uses energy for its manufacturing process, packaging for its products, if it produces waste or uses transport to provide a service, all of which have an environmental impact, it will face an ongoing challenge to improve for the benefit of the environment References European Union, Regulation No 761/2001 of the European Parliament and of the Council of 19 March 2001 allowing voluntary participation by organisations in a Community eco-management and audit scheme (EMAS), European Union, Luxembourg (2001) British Standards Institution, BS EN ISO 14001, Environmental Management Systems, Specification with guidance for use, BSI, London (1996) British Standards Institution, BS EN ISO 9000, Quality Systems, Specification for the design/ development, production, installation and servicing, BSI, London (1994) British Standards Institution, OHSAS 18002: 2000, Occupational health and safety management systems, BSI, London Chemical Industries Association, Responsible Care Management Systems – Guidance, Chemical Industries Association, London (1998) Environmental Protection (Duty of Care) Regulations 1991, The Stationery Office, London (1991) Chapter 5.3 Waste management Samantha Moss 5.3.1 Introduction In prehistoric times, waste was mainly composed of ash from fires, wood, bones and vegetable or bodily waste It was disposed of into the ground, where it would act as a compost and help improve the soil Waste began to be a problem as the transition came from hunter-gatherer to farmer The industrial revolution led to a massive population shift from rural areas to the city between 1750 and 1850 in the UK The growing population living in towns led to an increase in the volume of domestic waste arising, which was matched by the production of industrial waste from new large-scale manufacturing processes As city populations expanded, space for disposal decreased and societies began to develop waste management systems Prior to 1972, there were few controls on waste disposal The power to inspect first appears in the Public Health Act 1848 and the duty to so in the Sanitary Act 1866 These powers and duties could not prevent the nuisance arising from wastes but at least they should have ensured there were no unknown major toxic waste deposits In 1875 the Public Health Act charged local authorities with the duty to arrange the removal and disposal of waste and signified the start of significant local authority power This Act also ruled that householders had to keep their waste in a ‘movable receptacle’ (the early dustbin) which local authorities were required to empty every week Most waste in the UK had been sent to landfill, a practice that had little impact until concern arose over uncontrolled dumping of toxic waste forced the introduction of the Deposit of Poisonous Waste Act 19721 However, growing concern about the environmental effects of waste in the 1960s led the Government to set up two working groups The resulting reports paved the way for the Control of Pollution Act 19742 which aimed for much wider control on waste disposal and regulation of sites Several provisions from the Control of Pollution Act have been transferred to the Environmental Protection Act 19903 Part of this Act 921 922 Safety at Work introduced a new statutory regime for the control of waste, introducing stricter controls and placing responsibility (the ‘Duty of Care’) on waste producers and persons who may handle waste More recently, the Environment Act 19954 repealed a number of areas of the 1990 Act and from both these key pieces of legislation, a number of UK regulations have been enacted to address the implementation of good waste management practices 5.3.2 Waste authorities The Waste Disposal Authorities continue to exist mostly as County Councils in England, District Councils in Wales and Islands or District Councils in Scotland These bodies not undertake disposal themselves but will contract this service to private operators or Local Authority Waste Disposal Companies The Environment Agencies of England and Wales (EA) and the Environment Protection Agency of Scotland (SEPA) were established by the Environment Act 1995 and now have responsibility for waste regulation Together they manage and monitor the environment through the enforcement of a full range of environmental legislation dealing with sitebased emissions, and increasingly seeking to influence the controls, checks and balances that are evolving with emissions that arise from the use of products 5.3.2.1 Regulatory waste management responsibilities of the environment agencies The key aspects of legislation from which the agencies with responsibility for environmental protection derive their waste management duties and powers are: ᭹ ᭹ ᭹ ᭹ ᭹ Control of Pollution (Amendment) Act 19895 Controlled Waste (Registration of Carriers and Seizure of Vehicles) Regulations 1991 and amendment 19986 Waste Management Licensing Regulations 1994 and amendments in 1995, 1996, 1997, and 19987 Transfrontier Shipment of Waste Regulations 19948 Environment Act 19954 In addition, the Environment Agency has taken on new responsibilities since it was established in 1996 as a result of the following legislative provisions: ᭹ ᭹ The Special Waste Regulations 1996 and amendments in 1996 and 19979 Finance Act 1996 and Landfill Tax Regulations 1996 and amendments in 1996, 1998, 1999 and 200210 Waste management ᭹ 923 Producer Responsibility Obligations (Packaging Waste) Regulations 1997 and amendments in 1999 and 200011 5.3.3 National waste strategies The waste management industry faces a tremendous challenge in the 21st century as it seeks to develop and implement sustainable waste management practices Waste managers need to ensure that their activities conform to a range of government policies reflecting both EU and UK legislation and national waste strategies including the Government’s vision on sustainability This vision is based on four broad objectives: ᭹ ᭹ ᭹ ᭹ social progress which recognises the needs of everyone; effective protection of the environment; prudent use of natural resources; and maintenance of high and stable levels of economic growth and employment Waste has two main impacts on sustainability: first, the amount of waste produced is a consequence of how efficiently resources to produce goods are used and of the quantity of goods produced and consumed and, second, once waste has been produced, the aim should be to manage the waste to minimise the impact on the environment The waste strategies for England, Scotland, Wales and Northern Ireland, seek to ensure that waste management plays a major role in the search for increased sustainability They focus on measures to achieve waste minimisation and re-use and for the management of wastes to be carried out in an environmentally responsible way Under the Kyoto Protocol, the Government has agreed to legally binding targets to reduce greenhouse gas emissions to 12.5% below 1990 levels over the period 2008 to 2012 and has a domestic aim to reduce CO2 emissions by 20% by 2010 Waste managers need to strive to work within a sustainable waste management framework, with regulatory regimes that prescribe the rules for environmentally responsible operations and practices To achieve this task it is necessary to look forward and consider the impacts that these products have during their use downstream 5.3.3.1 Waste strategy for England and Wales 2000 This strategy was published as a requirement of the Environmental Act 1995, and describes the vision for sustainable waste management by preparing a strategy for the recovery and disposal of waste The strategy clearly identifies landfill as the least desirable option to tackle waste and identified an urgent need to stimulate waste minimisation, recycling and greater resource efficiency to reduce amounts of waste disposed to landfill One of the key targets in this strategy is that, by 2005, the amount 924 Safety at Work of commercial and industrial waste sent to landfill is reduced to 85% of the 1998 level This is to be achieved by focusing on recovering value, reducing environmental impacts and addressing growth in wastes Based on figures from the National Waste Production Survey12 (commissioned by the Environment Agency in 1998 and covering 20 000 businesses in England and Wales) this translates into a reduction of around million tonnes of waste going to landfill per year In addition targets have been set that increase the amount of municipal waste that is recycled, aiming to recycle or compost at least 25% of household waste by 2005, 30% by 2010 and 33% by 2015 5.3.3.2 Waste strategy for Scotland 1999 This strategy, which was published by SEPA in 199913, sets out the system for sustainable waste management through the implementation of several key tools including statutory functions, education, economic instruments and focused waste management research and development 5.3.4 Defining waste The first key task is to ascertain whether or not the material in question is actually a waste according to the legal definition before any attempt is made to classify it appropriately This is a complex process that begins with the definition of waste which is given in European Waste Framework Directive14 and with detailed guidance given by the Department of the Environment in Joint Circular 11/9415 The main questions to be considered are outlined in Figure 5.3.1 and should assist in reaching a view on the status of the material It is the responsibility of the waste producer to decide whether the substance or object in his possession is waste This decision is not always straightforward and final interpretation may be a matter for the courts Figure 5.3.1 Identifying waste Waste management 925 However, in a case where the holder is in doubt about the status of a substance or object as waste the regulatory authority should be consulted In order for material to be classified as a certain type of waste, such as a controlled waste, a substance or object should meet the definition of ‘directive waste’ as set out in the Waste Framework Directive and its amendment and reflected in section 22 of the Environment Act 1995 and the Waste Management Licensing Regulations 199416 This definition is based on whether the producer or person in possession of the material in question has discarded it, intends to or is required to discard it Guidance on how this definition should be interpreted is given in Department of the Environment Circular 11/9217 now replaced by Circular 04/2000 However a number of questions can be posed in order to decide whether or not something is a waste: ᭹ ᭹ ᭹ ᭹ ᭹ ᭹ ᭹ ᭹ Is the substance or object still part of the commercial cycle (i.e the producer’s main activities) or chain of utility (i.e if an object has been given away but is still being used for the purpose for which it was made)? If it is part of these, then it is fair to assume that it is not a waste Has the item been consigned to a disposal operation? If so it is almost certainly a waste Has the item been abandoned or dumped illegally? If so, it is a waste Has the item been consigned to a specialised recovery operation? If so it is likely to be a waste (A specialised recovery operation is one which recovers or recycles materials which otherwise could not be used.) Can the item be used in its present form without being subjected to a specialised recovery operation? If so it may well not be a waste (e.g bottles returned for refilling) Does the owner have to pay for the item to be taken away? If so, it is likely to be a waste Will the person receiving the item regard it as something to be disposed of rather than as a useful product? If so it is a waste Has the item been reprocessed so that it can re-enter the commercial cycle (e.g a recycled solvent which can be sold back to a purchaser)? This is no longer a waste There are a number of terms that describe a waste in legislation of which the main terms of reference used in UK law are: ᭹ Controlled waste is defined in the Controlled Waste Regulations 199218 and section 75 of the Environment Protection Act 1990 as wastes from households, commerce and industry Wastes excluded from this definition include explosives, wastes from mines and quarries or agricultural wastes Wastes included are: ᭹ Household waste: from a domestic property, caravan, residential home, educational establishment, hospital or nursing home ᭹ Industrial waste: from a factory or from a premises used for or in connection with, the provision of public transport, the public supply of gas, water, electricity or sewerage services, and the provision of postal or telecommunication services 926 Safety at Work Commercial waste: from premises used for trade or business or for the purposes of sport, recreation or entertainment Hazardous (special) waste: is controlled waste which, because of its hazardous properties, is subject to additional controls under the Special Waste Regulations 1996 (see a later section for further details) There are a number of guidance documents produced by regulatory authorities that further explain aspects of the definitions and the UK interpretations The Environment Agency Special Waste Explanatory Notes19 are particularly helpful Difficult waste: is a term used to describe wastes that could in certain circumstances be harmful to human health or the environment in the short or long term due to their chemical or biological properties This term incorporates wastes whose physical properties present handling problems at the point of disposal Clinical waste: the definition of clinical waste is given in the Controlled Waste Regulations 1992 in terms of two hazardous properties – infectivity and toxicity Clinical waste includes: ᭹ Any waste which consists wholly or partly of human or animal tissue, blood or other bodily fluids, excretions, drugs or pharmaceutical products, swabs, dressings, syringes, needles or other sharp instruments, being a waste which unless rendered safe may prove hazardous to any persons coming into contact with it ᭹ Any other waste arising from medical, dental, nursing, veterinary, pharmaceutical or similar practice, investigation, treatment, care or research, or the collection of blood for transfusion, being waste which may cause infection to any person coming into contact with it ᭹ ᭹ ᭹ ᭹ 5.3.5 The waste hierarchy The government’s strategy for waste management promotes the ‘waste hierarchy’ as a guiding principle in the development of a more sustainable waste management system Following the hierarchy is also a cost-effective and environmentally responsible approach to managing waste The hierarchy ranks methods of waste management, defining elimination and reduction as the most desirable options followed by reuse, then recovery (through recycling, composting or energy recovery) and finally the least desirable option, disposal The terms are covered in Article of the Framework Waste Directive which states that member states of the European Union shall take appropriate measures to encourage the prevention or reduction of waste production and its harmfulness With reference to industry, actions which will not necessarily lead to waste prevention but reductions in product and/or packaging which lead to reductions in waste generated are to be encouraged It should be recognised however, that it is not always feasible (economically, technically or environmentally) to follow this strategy Other means and principles may be necessary to formulate local waste strategies such as the precautionary principle, the proximity principle, life Waste management 927 Table 5.3.1 The six-stage waste hierarchy Hierarchy Waste option Description and/or examples Most desirable Elimination Reduction Complete elimination of the waste at source The avoidance, reduction or elimination of waste generally within the confines of the production unit, through changes in industrial processes or procedures This may involve using technology which requires less material in products and produces less waste in manufacture and by producing longer-lasting products with lower pollution potential Examples are: returnable bottles and reusable transit packaging Involves finding beneficial uses for waste such as recovering energy by burning it; recycling it to produce a useable product or composting to create products such as soil conditioners and growing media for plants The destruction, detoxification or neutralisation of wastes into less harmful substances By incineration or landfill without energy recovery Secure land disposal may involve volume reduction, encapsulation, leachate containment and monitoring techniques  ᭢ Least desirable Re-use Recovery Treatment (Energy recovery) Disposal cycle analysis and the Best Practicable Environmental Option (BPEO), which all apply to decisions about waste management The BPEO is the option that provides the most benefits or least damage to the environment as a whole, at an acceptable cost, in the long term as well as the short term The Waste Hierarchy (Table 5.3.1) captures these concepts It is usually portrayed in a five- or six-stage list of options and strategies 5.3.6 Waste management in practice Most pollution incidents are avoidable and the costs for cleaning up a pollution incident can be very high Careful planning of facilities and effective operational procedures can reduce the risk of a loss of containment and simple precautions can prevent such a loss becoming a pollution incident This section covers the good practice and pollution prevention measures necessary to achieve compliance with legal requirements and minimise the likelihood of incidents Waste management processes are fundamental aspects of good business management and should be integrated into systems set up to run established business 928 Safety at Work Figure 5.3.2 Five steps in waste management operations There are five steps involved in practical waste management as shown in Figure 5.3.2 They are discussed more fully in subsequent sections 5.3.6.1 STEP1: Identify waste streams One of the first tasks of a waste minimisation programme is to identify and characterise the facility waste streams This information can be used to assess inputs of raw materials to the waste stream, how much raw material can be accounted for through fugitive losses, distinguishing large single waste streams from smaller constant flows and tracking wastes that may be subject to seasonal variations This is important data needed to establish effective and legally compliant waste management procedures as well as providing useful business information that can be used to improve process efficiency and minimise costs Further details on the practical methods for carrying out this type of assessment are covered in a later section on waste minimisation 5.3.6.2 STEP 2: Categorise waste according to legal definitions Once the list of waste streams have been identified and the decision has been made that the materials are in fact wastes according to the legal Waste management 929 Figure 5.3.3 Waste classification chart definition, the next stage is to ensure that the wastes are correctly classified Figure 5.3.3 is a waste classification chart demonstrating the process 5.3.6.3 STEP 3: Select the best waste management option The generation of waste is a common product of physical or chemical processing However, the quantity and toxicity needs to be minimised in order to protect the environment and the safety of the working population and public Waste minimisation can be achieved in many ways, through, for example, the design of processes and the selection of suitable raw materials which produce less waste, to the re-use and recovery of materials to avoid sending them for final disposal This decision-making process is referred to as the waste management hierarchy and has been covered previously The implementation of a waste minimisation programme to plan for waste elimination or source reduction options is covered in a later section The business considerations that form part of the decision to select the best environmental option for the waste material requires that an evaluation of the costs of waste minimisation, treatment and disposal be carried out on an equitable basis Alternative routes should be costed using as far as possible actual estimates and realistic assumptions about market values of recovered product The costs of all the elements involved in the process from collection to transfer, treatment and final disposal needs to be considered An analysis should therefore take account of the following: ᭹ ᭹ ᭹ ᭹ ᭹ ᭹ labour costs of collection, delivery and disposal administrative costs of collection, delivery and disposal site purchase costs capital costs of equipment operating costs of equipment i.e fuel, maintenance, insurance disposal costs i.e landfill charges including tax, incinerator fees 930 Safety at Work The costs of any recycling schemes that may be associated with the overall strategy will also include: ᭹ ᭹ ᭹ ᭹ ᭹ ᭹ labour and administrative costs of collecting and delivering recyclables either to a market or a processing facility residual disposal costs labour and administrative costs of processing capital costs of the recycling equipment such as vehicles, materials handling and processing facilities operating costs of recycling equipment, such as fuel, maintenance and insurance administrative costs of the recycling scheme including the costs of promotional materials, advisory and marketing services The revenues and savings from a recycling scheme include: ᭹ ᭹ revenues from the sale of materials any revenue from commercial sponsorship of the scheme The process of financial appraisal should take into account both shortand long-term costs taking note that some of the figures will be estimated as the market value may fluctuate with supply and demand 5.3.6.4 STEP 4: Prepare and implement a plan to manage wastes on-site Waste poses a threat to the environment and to human health if it is not managed properly and recovered or disposed of safely It is critical to good business practice to ensure that environmental legislation is not breached by a lack of understanding of key legislative requirements or poor implementation of waste management procedures To avoid such risks arising, the responsibility for managing this process should be identified and appropriate resources allocated There are many aspects to be considered such as waste containment, segregation and storage, waste treatment, handling and the preparations necessary to transfer the wastes off-site to the next stage of the management cycle All these areas have clearly defined expectations set out in various legal statutes and Codes of Good Practice The key requirements in this area are set out in this section and should be considered in the development of a strategy to manage the company’s wastes while on-site 5.3.6.4.1 The Duty of Care The basic guiding principles and controls required for good on-site waste management practice are set out in the Duty of Care concept which places a duty on anyone who in anyway has a responsibility for controlled waste The Environmental Protection (Duty of Care Regulations) 199120, issued under section 34 of the Environmental Protection Act 1990, detail Waste management 931 the strict waste management controls to be implemented by the waste holder The waste holder is defined as ‘any person who imports, produces, keeps, treats or disposes of controlled waste or as a broker has control over it.’ A clear understanding of this regime is necessary to implement the different elements that apply These are clearly set out in the guidance document ‘Waste Management, The Duty of Care A Code of Practice’21 issued by the Department of the Environment, which recommends a series of steps which should normally be sufficient to meet the Duty of Care The Duty of Care places the holder of the waste under a duty to take all measures, applicable to him in that capacity, as are reasonable in the circumstances The steps to be taken are: To prevent any contravention by any other person from disposing, treating or storing the waste without a licence, breaching the conditions of the licence or in a manner likely to cause environmental pollution or harm to health In practice this means that the waste producer must take all reasonable steps to ensure that all the waste is disposed of to suitably licensed sites and not fly-tipped at an unauthorised site If the waste was not handled correctly and the producer has failed to make reasonable checks, such as that the recipient’s waste management licence permits them to take the type and quantity of the waste involved, then the producer could be liable for breach of the Duty of Care Full checks not need to be repeated on each occasion if transfers of the same type of waste follow the same path, however licences should be examined when changes occur It is reasonable to go beyond licence checking for larger quantities of more hazardous waste which is likely to involve periodic audits at the disposal site to check that disposal takes place according to the conditions of the site licence To prevent the escape of waste from his or another person’s control The waste must be appropriately packaged in order to prevent foreseeable escape or leakage whilst on site, in transit or in storage Holders should protect waste against the risks posed by: ᭹ ᭹ ᭹ ᭹ ᭹ Corrosion or wear of waste containers Accidental spilling or leaking or inadvertent leaching from waste unprotected from rainfall Accident or weather breaking open contained waste and allowing it to escape Waste blowing away or falling while stored or transported Scavenging of waste by vandals, thieves, children, trespassers or animals On the transfer of waste, to secure that the transfer is only to an authorised person or to a person for authorised transport purposes On the transfer of waste, to secure that there is also transferred a written description of the waste which is good enough to enable each person receiving it to avoid committing any offences under section 33 and to comply with the duty of care relating to the escape of the waste 932 Safety at Work Points and are discussed in section 5.3.6.5 concerning off-site waste management Each holder in the chain has a responsibility to ensure that the duty is discharged while the waste is under his control Different measures are reasonable for each role For example, the holder acting as the waste carrier would not normally be expected to provide a description of the waste he collects from the producer unless for some reason he alters the composition of the waste 5.3.6.4.2 Waste management licensing This sets out a licensing system designed to regulate the deposit, keeping, treatment or disposal of controlled waste (i.e industrial, commercial or household wastes) on land Its objective is to prevent unacceptable environmental emissions by specifying the management system for a site or plant This regime was introduced by the Waste Management Licensing Regulations 1994 as required by the EC Framework Directive on Waste and is regulated and enforced by the Environment Agency All producers of waste need to understand the requirements of waste management licensing in order to assess whether or not they need a licence for the activities carried out on their site Although there is a broad requirement for licensing, it is equally important to establish whether or not the waste activities are categorised within an extensive list of activities exempt from licensing as set out in Schedule to the Waste Management Licensing Regulations 1994 Exemptions are permitted in circumstances where there are other adequate controls such as consents given under the Water Resources Act 199122 and for a number of specified activities carried out at the place of production of the waste (where waste is to be reused or recovered) or where small quantities of waste are being managed Exemptions must be registered with the Environmental Agency, giving them the business name and address, details of the activity which is exempt and the place where the activity takes place The Environment Agency are likely to specify appropriate terms and conditions in a licence and conditions will vary depending on the activity being considered Clearly conditions for a large and complex landfill site will be much more detailed with higher expectations set than for a simple treatment operation The conditions are likely to address the types and quantities of waste involved and operational issues such as monitoring, record keeping and controls which are set out in a work plan provided by the site operator The applicant for the licence must be a ‘fit and proper person’ to hold a licence and this will be judged according to the following considerations: ᭹ ᭹ If he or another relevant person has been convicted of a relevant offence The management of the activities would be in the hands of a technically competent person (holding approved waste management qualifications) Waste management ᭹ 933 The potential licence holder has made financial provision for the adequate discharge of the obligations arising from the licence The regulations further define requirements and procedures for submission of licence applications, surrender or transfer of licences, assessment of ‘fit and proper persons’ appeals and public registers 5.3.6.4.3 Good waste management practices To ensure that waste is properly controlled and managed the following techniques should be practised: A Waste storage Wastes will often have to be stored at some stage for varying periods of time Underground storage tanks are susceptible to damage and corrosion and therefore above ground storage facilities are preferred Any waste should be stored in a container that is appropriate for the volume of waste produced and the fabric of the container should be compatible with the nature of the waste, i.e its chemical or physical properties This means that wastes must not be kept in corroded, worn or damaged containers Metal drums are not always suitable for acid wastes and open-top drums are not suitable for liquid wastes Where waste is stored it should be placed under cover within a secure designated area that is regularly inspected Suitable secondary containment (bunding) should be provided for waste chemical substances to prevent any accidental release to the environment in the event of leakage, a spill or leaching Any bunding provided should be designed to contain 110% of the contents of the stored volume within it, without any drains or valves and should be routinely checked to ensure its integrity is maintained B Waste location All waste should be placed in a suitable location in order to avoid accidental contamination and to minimise its handling and transportation thus reducing the potential for spillage C Labelling of containers The labelling of all waste products is essential for two reasons: ᭹ ᭹ to ensure the correct segregation of wastes in order to avoid incompatible storage; to provide the appropriate labelling to indicate any hazardous properties that may be associated with it If containers have been re-used, it is important that they have been cleaned prior to refilling in order to remove any residue of previous contents and that old misleading labels are removed and replaced as appropriate 934 Safety at Work D Waste handling and deliveries The handling of materials involves risks of spillage and accidents It is important to identify these risks so they can be appropriately minimised The following aspects should be considered: ᭹ ᭹ ᭹ ᭹ ᭹ ᭹ ᭹ Loading and unloading areas should be designated, marked and isolated from the surface water drainage system The routes for the movements of materials on site should be identified so that any necessary precautions can be taken High-risk areas such as refuelling points should be isolated from the surface water system using ramped bunds or some form of restricted access Deliveries of oil and potentially hazardous materials should be supervised If there is a spillage it should be contained and reported immediately Tankers should discharge via a lockable fixed coupling within a bunded area Automatic cut-off valves should be fitted to delivery pipes to prevent overfilling Pipe couplings should be unique to the liquid being handled E Spillage and emergency response procedure Operators are expected to have in place procedures for responding to emergency environmental incidents Figure 5.3.4 provides an example of an emergency procedure Clearly set out and, depending on the waste and its properties, may need additional precautions to be added 5.3.6.4.4 Managing liquid wastes on-site There are three methods available for the disposal of trade effluent (liquid waste): ᭹ ᭹ ᭹ The transfer off-site for treatment and disposal by a recognised waste contractor Obtain a ‘Consent to Discharge Trade Effluent’ from the local Water Services Companies so that waste can be discharged to the drains onsite Authorisation is required in the form of a ‘Consent to Discharge Trade Effluent’ document issued by the sewerage undertaker (England and Wales) or Water Authorities (Scotland) These bodies are empowered to set conditions and levy charges on those who discharge effluent to the sewerage system Obtain a ‘Discharge Consent’ from the local Environment Agency if waste is to be discharged to controlled water (fresh and saline natural waters including rivers, streams, lochs, estuaries, coastal waters or groundwater) A consent to discharge to this media, is under the control of the Environment Agency (England and Wales) and the Scottish Environmental Protection Agency (Scotland) These bodies will set conditions and levy charges (These bodies also regulate the sewerage undertaker since they discharge to controlled waters following treatment that takes place at a sewage works.) ... the targets that have been set are being met Where the review highlights the need for changes in the system itself or the resources that need to be allocated, immediate authorisation can be given... known effect level This becomes the predicted no-effect concentration (PNEC) The more toxic a chemical appears, the more sensitive the species upon which the tests are performed before the precautionary... to recognise the interdependence of life He says that we not appreciate, for example, the dependency of the human being on bacteria to breathe and digest Consequently, in our ignorance we tear