Mike Farish reports on the methods being developed to reduce the amount of automotive manufacturing waste being sent to landfill.

A previously derelict parking lot in Detroit, Michigan, now bears the name Cadillac Urban Garden, marking the fact that the 250 plant beds it contains are made from redundant shipping crates donated from GM’s nearby Orion assembly plant for direct use in the community project rather being scrapped or recycled.

This green connection epitomises the holistic approach to modern industrial waste management that manufacturing companies of all sorts will increasingly need to act on. “It is not good enough just to recycle materials. You have got to reach out beyond your own walls on sustainability issues,” says John Bradburn, who manages GM’s waste reduction efforts worldwide. Bradburn, who is based right at the centre of the company in Detroit, explains that the issue is no longer merely technical, it is “informational” and finding effective solutions to specific waste management issues – certainly as part of major strategic company initiative such as GM’s – involves cooperation with a wide range of organisations, especially, but not exclusively materials and component suppliers. A core reason for this is simply to source ideas for the effective re-use of what might otherwise be waste materials.

Landfill-free plants

The initiative that provides a context for all GM’s waste management efforts is its commitment to making all its sites worldwide ‘landfill-free’, be they manufacturing, assembly or logistical. The campaign to do this has its roots in a decision taken as far back as 1997 to embark on a systematic analysis of the waste streams produced by its operations.

The first landfill-free site – the Flint powertrain manufacturing plant in the US – took until March 2005 to achieve, but in June 2012 a parts distribution centre in Lansing, Michigan became the 100th site within the global operation to attain that status. By the beginning of May this year that total had risen to 105 – 85 of them manufacturing sites recycling or reusing an average of 97% of all waste materials, with the remainder converted to energy through incineration.

At the moment, confirms Bradburn, some 2.4 million tons of various materials that might otherwise have gone to landfill are dealt with by one or other of these means.

Curiously, the first US assembly plant to achieve this status, the Fort Wayne truck site in Indiana, did not do so until late in 2011. Bradburn explains that this was due to a legislative requirement relating to the safe disposal of phosphate material used as a pre-paint coating.

Within GM itself, says Bradburn, the initiative is pervasive and involves staff at all levels. “There are environmental engineers in place at almost all our plants, as well as resource managers,” he states. He also emphasises that “plant managers are held accountable” and input is also required from areas such as purchasing and quality management. “It is about managing the total system in a better way,” he states.

Keeping your coolant

The coolant fluid used to lubricate and control the temperature of machining operations at the point where a cutting tool rotating at high speed comes into contact with a metal workpiece can be a particularly vexatious source of waste and operational inefficiency. Companies all too often keep the same fluid in use for weeks – even months – leading to degradation that impairs its effectiveness at reducing tool wear and makes working conditions unpleasant due to noxious bacterial growth in the fluid. Ultimately, the fluid will be drained and transported off site either for remedial treatment or disposal.

However, a US company called Universal Separators has a system called SmartSkim that can continually recycle and re-use fluid on site. The company is based in Verona, Wisconsin, though CEO Mark Kluis works out of offices in San Marcos, California.

Kluis says the system, which has been around for over a decade, consists of a standalone unit that can be co-located with production equipment for ease of access and fed with contaminated coolant as quickly as it is drained into a container and transported across to it. The fluid then undergoes repeated cycles of treatment over a period of 24 hours or so, at the end of which it is ready for re-use in an almost ‘as new’ state. Kluis says fluid that is three to four months old can be returned to the state it was in “after just a week of use.”

The fluid is subjected to two primary processes within the system. One is a relatively conventional metal-removal procedure that can remove both ferrous and non-ferrous swarf produced by cutting operations.

The other involves the use of what Kluis describes as a “coalescer”, which brings together the initially small droplets of ‘tramp oil’ from the machine tool’s own lubrication system that inevitably get into the cutting fluid, so they can be more easily removed. A third optional process is the use of an ozonator to introduce oxygen into the coolant as a counter to bacterial growth.

According to Kluis, the benefits of the system, assuming fairly constant use, could reasonably be expected to include a reduction in coolant consumption of at least 30% and maybe as high as 75% in exceptional circumstances. Though the need to remove spent coolant off-site would not be entirely eradicated, Kluis says the cost savings in that respect might reach as high as 90%. Overall he says an investment of between $15,000-45,000, depending on the required capacity, ought to pay for itself within 12-18 months.

A number of big automotive names use the system including Delphi, Nissan, Honda and Toyota. Another is CS Engineering Autoparts of Samutprakarn, Thailand, which started up a new factory with 128 employees in February this year. Its output includes a range of automotive and motorcycle parts for customers including GKN Driveline in Sweden. Production utilises over 70 different items of equipment from CNC lathes and machining centres to small manual machines.

Managing director Naruecha Sungkarat confi rms that a SmartSkim system has been in place right from the start of operations and has limited coolant consumption on a continuous basis. He says in the four months from January to April coolant purchases were, respectively, 6, 5, 4 and 3 200-litre barrels. The company is currently working to add the ISO 14000 environmental management standard to its existing quality management systems which include the ISO/TS 16949:2002 standard for automotive parts.

Putting in what you get out

Perhaps one of the most striking aspects of GM’s recycling activity is the way it feeds back not just into processes, but quite literally the vehicles themselves, as the company has started to incorporate recycled materials into new cars; materials that derive from the production processes rather than scrapped vehicles. At Fort Wayne, for instance, cardboard packaging is recycled into Buick Lacrosse and Verano headliners to serve as acoustic padding. In addition, absorbent pads used to soak up oil and water from production areas are initially cleaned and re-used up to three times, but will then be processed into Silverado and Sierra air deflectors, which also contain some of the plant’s former plastic packaging material.

Bradburn reveals that GM’s sourcing for such materials can be surprisingly inventive. As well as re-used plastic bottles and former polypropylene matting from production areas, some 25% of the baffles that covered the radiators of the whole of the 2010 production of the Chevrolet Volt was derived from the plastic booms used to help clear up the Gulf of Mexico oil spill that resulted from the accident involving BP’s Deepwater Horizon drilling rig. No less than 227 miles of the material was processed and subsequently utilised.

Filtering out the costs

A small outfit that helps GM – and also Ford and Chrysler – achieve landfill reduction objectives is Warren, Michigan’s Waste Free. MD Glenn Rowe explains that the business was set up eight years ago, as a subsidiary of a larger company called Crystal Filtration, to process rolls of polymer materials used as filtration media for coolant materials in the machining of both ferrous and non-ferrous metals.

The materials – which may be polyester, polyethylene, polypropylene or cellulose – arrive at the company’s processing site contaminated with metal fragments and ‘tramp oil’. They are first subjected to a physical ‘brushing’ to remove loose metal fragments and then cut up into smaller pieces ready for a ‘densification’ process developed by Waste Free. According to Rowe this is a combination of heat treatment to give the polymer a “putty-like” consistency and a subsequent quenching with water that produces a final “popcorn-like” material in which all the initial constituents are still present but in a state that is much easier to handle.

More importantly this final product can be used as an ingredient in cement making, so absolutely none of it goes to landfill. Rowe says the company is currently handling 1.5-2.0 million pounds of used filter media every year.

Waste Free is now also involved in developing a new procedure that could help retrieve the metal content that currently goes to a cement kiln for possible re-use in automotive manufacture and also the generation of useful ‘clean’ energy. This ‘gasification’ process is a further heat treatment carried out in an oxygen-free environment in order to separate the organic and inorganic constituents with the former turned into a ‘syngas’ that can be used as a fuel and the latter – the metals content – made available for re-use.

The new process is, appropriately, being developed by a new company – Resource, Recovery and Recycling (R3) based in River Rouge, Michigan – which is a joint venture between Waste Free and Carmeuse Natural Chemicals, the US arm of the Belgian-based Carmeuse Group. But, interestingly, the technique has the potential to be extended beyond the processing of filter media to deal with one of the industry’s more vexatious waste materials – paint sludges. Rowe says more needs to be done to refine the process to deal with this material but that work will start this summer with the nearby Oakland University. He indicates that the process ought to be able to recover as much as 25% of the sludge for re-use, with the rest going to energy.

Sourcing performance materials

Beyond the details of such cases there are some more general points to be made. One that Bradburn concedes is that while some sources of recycled material, such as plant packaging waste, may be constant, others such as the boom material are not. Therefore the specification for relevant parts has to be based on performance and not a particular material source. “You have to achieve a consistency of material from a variety of sources,” he states. In turn, a further implication is the need for the involvement of design staff – a confirmation of Bradburn’s observation that effective waste management involves a company-wide range of stakeholders.

Another concern is the relative ease or otherwise with which materials can be recycled. Those with the longest established traditions within the industry and the greatest value as raw scrap – most obviously metals – are the easiest.

Conversely, the most challenging, not merely technically, but also economically, will be those that involve a mix of substances requiring separation from each other and in which the base material will have little intrinsic value in its raw state. The mix of polypropylene filters and used machining coolant fluids is a prime example.

Another material source that Bradburn describes as “particularly challenging” is packaging. The core issue here is the choice between recycling and re-use and the decision is as likely to involve logistics and material properties. Put simply, a global supply chain may well involve logistic costs that will militate against the re-use of transport media such as pallets and instead create a need for recycling. In contrast, a geographically more compact ‘regional’ supply infrastructure is more likely to facilitate a ‘return and re-use’ policy that will entirely obviate any related need for waste management.

It seems evident that there will always be waste materials of some sort to deal with and technology, as well as procedure, will continue to have its uses in dealing with them. At the moment, Bradburn indicates, GM is interested in the potential of two particular techniques; “plasma gasification” and “microwaves”.

The latter, he indicates, could provide a means of dealing with materials containing organic compounds, such as foundry sand, using a lower energy consumption than present methods. The former could provide a means of turning into syngas various materials including cardboard and sludges. It also, perhaps summing up how GM sees waste management, has the potential to handle “varying materials on a continuous basis”.

Multiple -use recycling

Another small waste management specialist that is taking a highly innovative approach to the issue is Preferred Filter Recycling (PFR), which started up in Detroit in the middle of the last decade before moving to a new facility in St Clair Shores, Michigan last year. As president Dan Chrzanowski confirms, the move will enable the firm to ramp up the volumes of the materials it handles in a process that entirely avoids any requirement for landfill and achieves complete ‘cradle-to-cradle’ re-use of filter media used to capture not just machining coolants, but also ‘wet’ and ‘dry’ paint materials, floor spills and airborne contaminants generated during manufacturing operations.

The actual use of the polypropylene-based media is conventional enough, as is their return to PFR and their initial treatment to remove excess contaminants, but they then go through a six-stage heat-based process that reduces them and the residual contaminants they contain into resins that can be moulded into new products. Perhaps the most striking of the re-use options is that the polypropylene filters, infused with otherwise vexatious wet paint sludge, produce a robust resin that can be used to make industrial-grade pallets in addition, Chrzanowski stresses, to enabling the re-use of the previously retrieved sludge.

The precise details of the process, which was developed by Chrzanowski and his son, are covered by patent and remain confidential, but the firm has already established itself in the US automotive industry. Chrzanowski says the company’s original plant was handling almost 500,000kg of material a year derived from numerous sources in a roughly 200-300 mile radius of Michigan. Some “95%” of the material involved, he adds, was derived from automotive manufacturing, with source plants including a dozen GM sites with other OEM involvement from Daimler and Chrysler.

Meanwhile the new PFR site has been undergoing a re-certification process that has seen it get back to the level of material throughput that the old one enjoyed and a throughput of 2,500,000kg of material is expected by the end of next year. Three years from now, Chrzanowski adds, the total being handled by PFR, which will also be working with some other specialist waste management operations, could be as high as 10,000,000kg a year with expansion not just throughout the US but also into Europe already on the agenda. Chrzanowski is confident the business case will prove highly persuasive to new customers as he says the process offers clients distinct cost savings in the range “5-10%” over alternative waste disposal methodologies.

Constant re-evaluation leads to constant waste reduction

GKN Structures in Telford, UK employs some 630 people in the manufacture of steel and aluminium assemblies for use in passenger and commercial vehicles as well related off-highway and military applications.

According to operations director Neil Geldard-Williams, processes carried out at the site include pressing, fabrication, painting and assembly, but as recently as 2009 the plant paid little attention to waste management issues beyond meeting statutory requirements for hazardous materials, resulting in 12 tonnes of waste materials going to landfill each month.

However, following hard on the heels of the inception of what has proven to be a highly successful energy management initiative, which in the three years to the end of 2012 cut the plant’s electricity consumption by 51%, it decided to subject its physical waste streams to a similar exercise. Indeed the two are symbiotic. The individual with day-to-day responsibility for overseeing the waste management initiative, Adrian Stone, is also the site’s overall ‘energy champion’. “Energy management is about processes and waste management about materials generated by those processes,” he remarks.

The first step in the initiative, says Stone, was simply the setting up of a ‘waste management yard’ in which all the waste materials produced by the plant – including plastics, paper, cardboard and wood – were gathered and segregated. The exercise did not produce major surprises, “we knew what we were producing,” he states, but nevertheless did reinforce the recognition that there was a lot that could and should be done.

Both Stone and Geldard-Williams do concede that some waste streams which might otherwise have gone unremarked did become evident. This was the case, for instance, with used welding helmets and gloves. The fact that the latter were, as Stone notes, “£3 a pair” was a spur to action.

Most of what has followed has involved changes in attitudes and methodologies rather than technologies. Indeed, Stone confirms that none of the operation’s actual manufacturing processes have been altered in any way. Instead the emphasis has been on sorting waste materials and finding alternative uses for them after they leave the site. Nevertheless, the whole initiative starts at the factory floor level where a series of other ‘champions’ – there are currently eight in total – have been trained up to “conduct audits” to provide the raw data from which targets for action can be prioritised. The basic aim is to find waste streams that are sufficiently homogenous and free of contaminants to be sent straight for re-use or recycling elsewhere.

This simple approach has proved remarkably effective and has more than halved the amount of waste materials being sent to landfill. The initial 12 tonnes per month, says Stone, is now just five. The ‘filter cake’ resulting from painting processes, for instance, can be used in the construction industry. Wood waste can also be sent for further processing as can plastics and cardboard.

In addition, the initiative has been broadened out to involve suppliers. An example concerns parts delivered from a Turkish company that were originally wrapped in oiled paper as an anti-corrosion measure. But that material was officially classed as hazardous waste and had to go to landfill. It has therefore been changed to a plastic wrapping, which is just as effective and can be sent for recycling with other such materials.

Moreover, all of these activities have proven ‘cost-neutral’. The offset in landfill tax that might otherwise have been incurred has met such costs as those of a couple of contractor staff who manage the waste yard. In parallel, though, one significant investment in new equipment has been made – roughly £10,000 on an oil-water separator that allows an on-site effluent plant to clean up waste water sufficiently for it to be discharged into a canal that runs through the site, so just the oil rather than the previous much more voluminous oil-water mix need be transported off-site. Stone says it has paid itself in just 12 months. He adds that other forms of waste water generation are now being targeted including that produced by the apparently mundane task of floor-washing with increased use of captured rain water a likely option.

The whole approach has been pragmatic with ‘zero-to-landfill’ a distant rather than immediate target within a short timetable, but, says Stone, the initiative is pursued relentlessly on the basis of “constant re-evaluation” of relevant opportunities and techniques. As he puts it: “If we achieve a target within the set timescale we don’t then just sit back and do nothing.”