Increasing the efficiency of operation in a waste transfer station

Non-stop waste reduction Increasing the efficiency of operation in a waste transfer station

To hit recycling targets, more practical solutions are urgently needed to offset rising fuel costs and, at the same time, reduce ‘waste miles’, argues Waste Management World’s transport specialist, Malcolm Bates. Here, he explores the imaginative use of hooklift containers, a 360° excavator and a boom-mounted crusher wheel, and concludes that sometimes, simple ideas really are the best
Hooklift truck/trailer combinations are one of the most versatile ways of collecting and transferring waste materials for recycling
Increasing industrialization and urbanization are leading to more and more ‘waste’ globally – a trend that will be difficult to stop. In the Western world, and the US in particular, we have been encouraged over the past 50 years by the advertising industry, supermarkets and indeed our governments to aspire to more. Reducing consumption and the resulting waste isn’t going to be easy. So we have a responsibility to deal with the waste that we produce in the most efficient way possible, with maximum resource recovery and minimum greenhouse gas emissions. Waste transfer stations are under pressure to have greater capacity and operational efficiency.
Traditionally, amenity waste sites, or ‘bring sites’, have a row of hooklift demount containers lined up, side-by-side, so that materials can be loaded, either by sliding rail-mounted compaction hoppers, or a simple raised platform over which contractors and/or the general public throw waste materials manually. Once full, these containers are dragged onto the truck to be taken away for disposal. Long lines of containers, with space for hooklift trucks to manoeuvre and swap over empty and full units, take up a lot of space and as many sites are of a restricted overall size, there’s often little opportunity for expansion. So what’s to be done about increasing capacity and efficiency? Compaction could be the answer – reducing the volume of waste gives a site the potential to handle more of it and also leads to fewer truck movements or waste miles and as a direct result, less use of fossil fuels.
The equipment
Thankfully, a simple solution is readily available in the form of the 360° excavator and the telehandler. Normally, a purpose-built 360° ‘materials handler’ would be used to pick and sort waste with either a bale clamp, clamshell bucket, or grab attachment. But I’ve recently spent the day operating a closely related hybrid machine that offers a great deal more potential. This system offers increased productivity and reduced vehicle movements for little or no increase in capital budgets – while utilizing equipment that is already in use.


The MHF Minimyza waste reduction crusher wheel unit is fitted to a JCB JS–130 excavator, mounted directly onto a hooklift demount subframe
Some years ago, Waste Management World went to France to look at the mobile ‘Packmat’ container waste compacting systems manufactured by JSB Constructions. In the UK, a commercial waste contractor is using the same basic concept to double the amount of household waste loaded into a typical 20 tonne hooklift container – that is, compacting the waste so the container ‘weighs out’ before it overflows in volume terms. That alone could halve truck movements, but I’m told a reduction of ‘up to five out of seven container movements’ is possible on green waste and other bulk packaging materials. However you look at it, that equates to a significant reduction in fuel costs, driver’s hours, and a reduction in ‘waste miles’ per tonne.
To gain a greater understanding of the issues, I went to see MHF’s waste transfer site in Worcestershire, UK. In many ways, the 60-strong fleet of skip trucks and hooklift demounts operated by this company is entirely typical of a successful waste contractor. The company has increased the percentage of materials it sends for recycling, in order to reduce the amount of money it pays in landfill taxes. But to achieve this, MHF is facing ever-longer journeys – and ever-increasing fuel costs.
As one of MHF’s regular contracts covers the removal and disposal of waste materials from building refurbishment projects – such as old wooden window and door frames – the company was looking for a way to ensure trucks taking this material over longer distances were loaded to the maximum legal capacity, rather than with ‘fresh air’.
MHF has designed and built its own ‘waste reduction system’ – which it calls the ‘Minimyza’. Like the Packmat, the Minimyza is a compactor/crusher wheel, mounted onto a hooklift subframe. But unlike the Packmat – and some other systems – the Minimyza is attached to the boom of a standard 360° excavator which has been stripped of its undercarriage and mounted onto a hooklift subframe. This ensures that all the hydraulic functions are self-contained, familiar and above all, rugged enough to stand a life in the waste sector.
Or perhaps that should read ‘a second life’, as, originally, company principal Martin Fernyhough saw the building of a number of truck-mounted Minimyza units as an ideal way of utilizing retired front-line 360°s from his hire/rental fleet, as the undercarriage of the machines tended to wear out first. Considering the original prototype machine was built over five years ago – on an already ‘used’ 360° machine – and is still out on hire, it certainly seems rugged enough!
The Minimyza comprises twin hydraulically-driven crusher wheels complete with a ‘sheepsfoot’ pattern – just like a landfill compactor – mounted either side of the dipper boom. The wheel assembly weighs just over one tonne, but the waste reduction process is aided by the ability of one side (or the other) to be counter-rotated. Unlike some competitive machines, the Minimyza does not rely on the machine operator to ram the weight of the excavator boom down into the container in order to crush the waste. Instead, the boom controls are not touched once the unit has been lowered into the container.


With the rear jackleg stabilizers down to isolate the truck’s suspension, the Minimyza works safely at full outreach compacting the waste in the container to the left of the ‘X-formation’, leaving the others free for loading
A hydraulic valve enables the whole wheel assembly to ‘float’, while the forward/reverse action is activated by the redundant tracking control levers and pedals of the host excavator. Or at least this is the case when the Minimyza is specified as a truck-mounted system – on a normal 360° wheeled or tracked machine, the auxiliary breaker circuit controls are utilized.
Developing the concept
But if the Minimyza is more than five years old, does it qualify for a ‘new ideas’ article in 2008? Yes – because it often takes a good idea several years to be recognized and while the world of waste handling and transportation was far from easy five years ago, things have got far more difficult since. For example in the EU, legislators have now turned their attention to driver’s hours and what drivers do when they’re not driving on the highway. As time spent loading, or shifting containers around within the depot site now has to be recorded, operators have to turn trucks around ever more quickly. But ‘speed’ can conflict with safety, so any new system has to be foolproof.


Another simple solution. The BinBuncha attachment fitted to a JCB ‘Loadall’ telehandler is slotted into the container ‘hook’ to drag it away
MHF showed off a new Minimyza demonstration unit – utilizing a JCB JS–130 structure mounted onto a DAF CF 3-axle truck chassis – at the RWM exhibition at the NEC Birmingham, UK in September last year, alongside a second innovative product, the ‘BinBuncha’.


The weight of the container is supported by the central jockey wheel rather than adversely affecting the stability or traction of the telehandler
The BinBuncha attachment enables hooklift containers to be moved by a telehandler around the waste transfer site, more safely. Locating on the container hooklift ‘eye’, it fits onto the Q-Hitch carriage of a telehandler and takes the weight of laden hooklift containers on a central ‘jockey wheel’ to ensure the telehandler stays stable under all conditions – an important safety consideration when moving fully laden containers around a depot site.
Continuous working
After taking a few minutes to familiarize myself with the controls, I was ready to start work. But MHF had one more surprise in store. This innovative company has recently also devised a different working method that I had not seen before, whereby the hooklift containers were not lined up, side-by-side, but arranged in a ‘X-shaped’ formation.
The truck-mounted Minimyza was parked to form one leg of the ‘X’, with each of three hooklift waste containers arranged at 90 degrees to each other in the yard. In other words, from the cab of the JS–130, facing to the rear of the truck cab with the jackleg stabilizers down, I had one container ahead of me, one at right angles to my left and a third to my right. All three were within easy reach of the standard dipper boom of the 13-tonne JS–130, without the truck itself having to be moved.
The idea is a simple one – rather than the operator of the Minimyza having to stow the boom after each operation, lift the stabilizers, jump out of the excavator cab, climb up into the truck cab, move it – and then repeat the process over again to service each container in a line, the team at MHF reasoned that by using a telehandler with a BinBuncha unit, processed containers could be pulled out when full (and taken to an area where hooklift trucks could pick them up in safety) and replaced with empty units. This enables the Minimyza to work continuously, while a wheeled loading shovel (or another bucket-equipped telehandler) loads the third container.
Segregating the loading process from visiting trucks by using the BinBuncha has obvious safety advantages – especially as some depot sites are forced to close down while container transfer operations take place. But the ‘X’ formation of containers also enables three machines to work together in greater safety.
Does it work? It certainly does! In what seemed like no time, Martin Fernyhough’s son Guy was signalling that we’d used up all the unprocessed material in the yard and would have to wait until more arrived. By using the Minimyza, each container took three to four times the volume of waste before it ‘weighed out’. Also, full (by weight) containers were loaded well below the top rave, making sheeting a safer – and far less damaging – prospect. But the most impressive aspect was the speed of the process.
The bad news? I can’t think of any. Any make of 12 to 20 tonne 360° can be used, as can any make of hooklift demount body system. Using a hydraulically driven crusher wheel system fixed onto a 360° boom is more expensive than using an unpowered crusher wheel attachment (although that is still an alternative), but MHF claims that container damage is much reduced by using a powered system. Also, going for a truck-mounted option enables the unit to travel at normal highway speeds between smaller depots – reducing the need for dedicated units at each facility. This ensures that a constant flow of hooklift trucks isn’t required during weekends, or holiday periods as any given container capacity can be stretched to last longer.
MHF is looking to license the design and manufacture of the Minimyza worldwide, and I can’t think of any other single system that can double the capacity of a site, and cut the number of truck/container movements by at least 50% while handling the same tonnage of material.
Malcolm Bates is Transport Correspondent of Waste Management World e-mail: wmw@pennwell.com [/left]