Pollution Solution01 February 2006
Whether you look at the heavy engineering manufacturers, pharmaceutical, petro-chemical, or continuous process industries, copious volumes of dust and fumes are generated. These fumes and dusts have to be processed before they can be vented to atmosphere, or disposed of by waste disposal. Similarly, the refurbishment, renewal, upgrade or decontamination of surplus plant and machinery require equally careful handling.
In these areas, the facilities management (FM) companies are playing a major role in implementing new installations, decontamination, renewal and maintenance services to industry. Engineers working in this field have to handle, and enable the safe disposal of airborne pollutants - toxic fumes, gases, odours and particulates in atmosphere. Airborne and other substances, together with the risks they pose, are identified in a range of guidance notes produced by the Health and Safety Executive (HSE), which also includes information on managing and reducing the environmental and people effects.
While specific industries such as petro-chemicals are obvious sources of environmental contaminants, the control of emissions covers all forms of economic activity. In many sectors, FM companies are employed to provide advice, guidance and operational support to businesses.
Key engineering challenges
Chemical processes, in particular, frequently involve intrinsically unpleasant materials such as acids or oils, and at the same time give rise to equally unpleasant odours and toxic gases. Similarly, dust particles that are present in the atmosphere as a result of the manufacturing processes cause particular biological hazards, and while the provision of self-contained breathing equipment tends to reduce the individual impact, it does pose operational constraints. The key challenges faced by engineers include:
- Metal fabrication industries, in particular, give rise to airborne particulates that stem from the use of welding processes
- Food processing industries, with dust from milling and mixing activities
- Chemical processing plant and the pharmaceutical industry, which are obvious sources of emissions
- The decommissioning of old factories, such as cotton mills, can be a challenge for FM engineers, with the removal of pipework, often lagged with asbestos, and the subsequent disposal of this highly toxic material.
The most common emission control challenges faced by engineers include Large Volume Organic Chemicals (LVOCs), including a range of hydrocarbons, the polluting emissions from which are VOCs (Volatile Organic Compounds) from continuous vents and fugitive emissions; SO2 emissions from combustion; and NOx emissions from combustion.
Surveying the risks
Taking on a new customer or site, the pre-requisite task is to carry out a risk assessment and site survey, to agree the maintenance and support regime with the customer. This can take many visits, and may result in changes, while engineers may be faced with the adoption of new tools and techniques. Most FM companies provide a range of services that include the design, manufacture and provision of air pollution control systems, decontamination and asbestos removal.
Knowledge of the contaminant, and its behaviour, or hazardous substance generated as part of the process is critical to the success of the project. The starting point for an installation is a detailed understanding of these processes, and where emission to atmosphere is involved, specialists will undertake a detailed survey of air-pollution levels. The audit will enable the provider to determine any necessary chemical scrubbers required to remove, or reduce the level of pollutant to the required level for that particular operation. During this initial survey stage to determine the hazardous materials being handled, any materials that are unknown or uncertain are sent away for detailed investigation and analysis by a third party.
Once a system has been installed and commissioned, the next step would be to create an 'emissions inventory', to determine what is being abated, and to what degree. A typical approach would involve going to customer site to conduct gas flow measurements, recording particulate levels, efficiencies, and so on, with the six-monthly or annual maintenance programme.
Tools & techniques
Equipment used for managing dust and fume control is diverse, including particulate filters, adsorption filters and chemical scrubbing systems. Carbon filters, activated charcoal, and urea as neutralising agents are commonplace. Urea is used in selective catalytic reduction techniques to control and reduce NOx emissions, considered to be one of the most damaging pollutants around today.
In processing plant where the product demands the use of gases or pollutants that need to be abated, wet or dry chemical scrubbing plant is used to remove odours and other atmospheric pollutants prior to venting to atmosphere. Many plants have two scrubbing units, giving the maintainer the opportunity to switch from one to the other, while undertaking purging and maintenance of the remaining unit.
This is especially important in continuous process operations, as it ensures minimal disruption to production. An FM company's customer base tends to include installations where scrubbing or filtration systems already exist, and the company offers consultancy services to enable additional systems to be installed alongside, operating in parallel as part of an upgrade or replacement project. The resultant reports include specific details of design, implementation and commissioning.
However, it is not just gases and fumes that need to be treated. There is also the problem of heavier particulates - dust is generated by many different activities, but most obviously perhaps in paper manufacture or food production. Abatement techniques for particulate matter typically use cyclones as gas-solids separators, while fabric and ceramic filters are also in common use. An obvious dust pollution problem is created by raw material storage facilities such as vats, tanks and silos, and in open spaces or bunkers where they may be covered. To prevent dust from becoming airborne, dust suppression techniques are used which include increasing the level of the moisture in the atmosphere on the surface of stockpiled, dusty material. Continual water sprays in open storage areas are frequently employed, with automated control techniques.
The design and installation of fans, ducting and filters is treated as a whole, and the provision of these assemblies are carried out against each specific process. The size and capacity of the fan, shape of the ducting and other enclosures will change according to the material that is being removed, and filters provided according to the particulate, vapour or gases that flow along the ducting.
Clearly the adoption of the right system design and controls leads to increased production uptime, lower maintenance costs and longer asset life.
In general, there is nothing that is done differently between customer sites, in terms of the principal activities, actions and practices, since the differentials are normally only those of scale of operation. More specialised processes, such as the control of radiological hazards come under similar, but very specific control regimes, and would need a separate article to discuss in themselves.
Elsewhere in industry, some minor differences faced can be in areas such as chemical suits, which are typically assigned permanently to an individual, perhaps working in-house on a decontamination project. But when going to customer sites, a different suit may be used along with the site-based breathing apparatus, air lines, BA sets and face masks.
Inspection
FM organisations in general have widely experienced personnel - covering decontamination teams, asbestos removal, or air pollution - and these skills are distributed between the teams to ensure cross-pollination of ideas and knowledge. The processes and practices used are the same, irrespective of industry type. The requirements regarding emission levels, health and safety of personnel, the public and the environment remain constant, but the scale of both installed plant, and its operation will vary. Overall, the FM industry and its engineers tailor their solutions and services to fit the precise need of the operation.
It was the case that under COSHH regulations for LEV (Local Exhaust Ventilation), weekly inspections, and full examination and testing every 14 months was the norm. This has now been rescheduled as an annual requirement, and for dust control, for example, including inspection and verification of the volume and flow, to ensure that the filters used were able to meet the demands.
The tools and techniques employed include widespread use of sensors, taking data feeds from automated valve and process controls, such as a SCADA system, to better monitor and manage the emissions and the environment.
SCADA systems deployed on customer sites are based around a PC, but again tailored to suit the process, whether removing airborne dust or fumes. A good example of how the scrubbing plant and monitoring systems can be deployed across different applications comes from IEM Technologies. One of its customers has an operation that uses WF6 (tungsten hexafluoride) gas, a particularly noxious substance, which combines with moisture in the air to form hydrofluoric acid. The installation from IEM used the same scrubbing unit, but altered its composition, and combined with the SCADA system, to accurately monitor concentration levels prior to venting.
Regulation and best practice
By far the most important change that has occurred in recent times has been the introduction of the IPPC (Integrated Pollution Prevention and Control) regulatory system. This regulation not only describes the rules and emission levels, but also provides guidance on the control processes that may be used, including advice, guidance and examples of the use of Best Available Techniques (BATs).
There are requirements under the IPPC for businesses and industry to create an emissions inventory, to describe the nature, quantities and sources of foreseeable emissions. There is potentially so much complexity and diversity, that software - the H1 Software Tool - is available to complete the assessment details for this inventory, including consumption as well as emissions information.
IPPC and other recent regulations have introduced significant changes to working practices, and with the removal of the three-day pre-notification for transport, FM companies now have ADR-trained drivers to collect contaminated equipment. In addition, everything now has a Waste Premises Code (WPC), and when taking on a new contract, FM companies must ensure that this is in place, or support the customer in obtaining a WPC. Overall, legislation can be a double-edged sword, but is predominantly an advantage, and while admittedly often complex, it does serve to improve both the workplace and the environment.
Education and training
With such an increasing level of regulation and legislation, quite apart from new techniques and technology, it could be supposed that maintaining currency of skills and knowledge is equally complex.
One of the biggest issues facing FM companies is finding engineers who have a background in this type of work, whether installing, maintaining or decontaminating and removal. Where the work involves upgrading or provision of installations, engineers are often recruited with an engineering/construction background and in-house training is provided on installation and commissioning on air pollution control, from design to plastic welding. Under decommissioning and decontamination work, operatives and engineers involved with asbestos removal are provided with training from specialist providers.
But it's a challenge to keep up to date and maintain currency of knowledge of regulatory changes, updates on legislation and changes to tools and techniques. Many organisations obtain monthly updates, transferring these to an easy to read memo and circulating to the engineers, with details of the most recent changes, and likely impacts. This communication is not a one-way street however, since the engineers provide feedback and responses from their experiences.
Within the FM companies, health and safety is of paramount importance, providing routine and regular health monitoring for engineers who will come into contact with hazardous materials. In this vital area, engineers are treated to rigorous medical examination and health monitoring, including annual lung x-rays for those working on asbestos removal.
SOE
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