Substantial funding to local authorities from 'The National Waste Minimisation and Recycling Fund', via DEFRA, has enabled the introduction of extensive recycling regimes without financially crippling the local authorities concerned, reports Alan MacLachlan.

In the case of more than one authority, it has been possible to revise the waste collection process and introduce new side-loading vehicles with interchangeable body chambers, wheeled bins instead of black sacks, and kerbside collection of recyclable materials.

When considering the introduction of suitable collection methods, or monitoring these following introduction, many factors must be taken into account. Probably the most important is to establish the proportions and weights of each material being collected and this is where information technology (IT) plays a crucial role in the form of electronic weighing systems.

Dynamic bin weighing

Although the inclusion of load cell indicators between the body and chassis of a collection vehicle will give an indication of total weight being collected, this will not differentiate between individual materials.

Underbody systems are more generally employed to monitor loading characteristics to avoid falling foul of 'gross vehicle weight' and 'axle loading legislation'. Multi-fraction collection requires a more scientific approach however.

Dynamic bin weighing establishes precise data on each collection route with regard to volumes being collected from individual geographic areas, and any subsequent variations to these ratios. Therefore, route planning can be more effective and the work of collection vehicle optimised. Adjustments may also be made to take account of seasonal variations such as an increase in garden waste for composting.

A further enhancement is the inclusion on wheeled bins of an RFID chip 'tag' installed in a chip 'nest' incorporated in the bin design. This can be programmed with an individual street and premise location, together with any other information deemed necessary. Again, data is captured during the emptying cycle when the RFID 'tag' is in close proximity to a receiving antenna located on the lifter mechanism.

Considering the technology

In January 2005, Cork County Council completed the implementation of what is referred to there as a 'pay-as-youthrow' programme.

The Cork weighing system comprises electronics from PM Onboard incorporated with Otto bin-lifters. The initiative has been met with widespread approval by householders who recognise the advantages to be gained.

It is far easier and cheaper for bin manufacturers to include RFID transponders prior to supply than it is to retrofit at a later date. Frankly, the cost and time involved in retrofit is potentially horrendous. So, let us take a look at what is available from the market leaders in certificated dynamic weighing systems here in the UK.

PM Onboard has worked in association with County Cork in the Republic of Ireland where 'pay-by-weight' has been a requirement since January 2005. The company claims to have 110 'BinWeigh' systems operating throughout Ireland, with a further 220 systems in place with UK local authorities and private contractors. BinWeigh is Class-4-certificated by Weights and Measures in the UK.

The system is broadly similar to others on offer in that load dynamic weighing is undertaken by load cells within the lifter mechanism. The data is processed via an onboard computer then either transmitted directly to the operational centre or downloaded upon return to the depot.

'Pay-by-weight' utilises an RFID chip discreetly mounted in the bin which communicates with an antenna receiver on the bin-lifter of the collection vehicle. PM Onboard RFID chips are now approved by Taylor for fitting to its newly-developed

'TagSafe' chip mounting system.

BinWeigh technology is backed-up with a software suite which has been written by in-house programmers and uses the Microsoft SQL server database management system. Another innovation available is the 'four60DB Comcentre'.

This is a cab-located computer-based communications centre capable of two-way 'real time' information transmission. Not only can weighing data be displayed, but also GPS positioning and e-mail instructions as well. Still photographs from a suitably mounted camera can also be viewed, transmitted or logged, showing any obstruction or access problems encountered.

PM Onboard has taken the total system concept one step further by entering wheeled bin manufacturing. A purposebuilt 37,000 square feet injection moulding plant has been built in Bradford following the signing of a partnership agreement with Greek manufacturers Helesi.

A complete range of bins will be manufactured here meeting European standard EN 840 - 1 / 5 / 6, and produced in accordance with BS EN ISO 9001. All types of RFID chips can be included to suit practically any wheeled bin container weighing application I am told.

Red Forge's Delta system

Red Forge has a Class 3 certificated dynamic weighing system available for both automatic and manual bin-lifter systems called 'Delta'. At the heart of this is 'Welvaarts' Class 3 technology from Holland, exclusively available in the UK from Red Forge.

Up to four individual bin-lifters can be monitored simultaneously by the in-cab computer which means that loading crew can work independently without having to wait for one lifter to complete an emptying cycle before activating another.

The computer also has the capacity for up to five RS232 ports to accommodate GPS, bar-code reading or any other input required, together with faster RS485 capability for RFID tag reading during multiple lifting sequences.

Red Forge claims that its Welvaarts computer is compatible with normal industry standard software, making it extremely flexible and capable of tailoring to almost any menu of functions. Customers can even load-up their existing waste management software if they desire.

An indinometer built into the system automatically compensates for collection vehicles at varying inclinations. The accuracy of the system is not compromised by slight rocking of the vehicle during the loading process as electronic damping parameters are included during the software settingup process. In the event of severe rocking, a red indicator is illuminated on the in-cab unit warning the driver to take remedial action.

Chips with everything

With more than 15 years experience in RFID chip-based bin identification and weighing systems, Sulo claims to be 'the leading pioneer' in this type of technology. Certainly, 35 million chips fitted to containers in Germany and the Benelux countries is a very strong argument in support. In the UK, around 250,000 chips have been installed and there are currently some 65 complete weighing systems in operation.

Sulo's DMWS 01 is a fully integrated Class 4 'dual chair' lifting and weighing system capable of handling wheeled bin containers ranging from 660 to 1280 litres. It comprises two weighing units, a weighing computer, an evaluation unit, and an onboard computer for data processing.

Continental split bin-lifter

One of the best known and respected names in bin-lifter manufacturing is Otto. The company's 'Continental' drop-down split bin-lifter is a firm favourite with many local authorities, and renowned for its sturdy, easy to maintain, design.

Keeping things simple, this lifter operates with one hydraulic cylinder, should equate to high reliability and low maintenance costs. The 'Continental' is bolt on mounting, has a working rave height between 1,300mm and 1,660mm, and a total weight of 835 kilograms.

Wheeled bins and containers from 60-litres to 1,100-litres can be accommodated, cycling at 8 seconds in double chair mode and 13 seconds in linked single trade lifter mode. Each chair has an individual lifting capacity of 225 kilograms. A feature of the 'Continental' is that it is particularly good at handling small wheeled bins without spilling refuse during the emptying cycle.

Otto also manufactures the 'Classic', a robust 'bar-hoist' type trade waste lifter with a lifting capacity of 250 / 500 kilograms. Working rave height is also between 1,310mm and 1,600mm, and total weight is 796 kilograms.

Dennis Eagle customers can complete the superb 'Elite 2' chassis with 'Phoenix 2' body combination by adding a 'Beta 2' bin lifter to the package. This is a bolt on lifter intended primarily for trade waste collection and has a lifting capacity of 500 kilograms. It can be supplied for 'lip' lifting wheeled bins only, or with additional 'Paladin' handling arms if required.

Terberg Matec UK launched the low-level 'Omni Dell' lightweight split bin-lifter at the CIWM Torbay 2004 exhibition. Weighing in at only 585 kilograms all-up, Terberg claims that 'OmniDell' is one of the lightest automatic bin-lifters available. It fits to a standard DIN frame and the hydraulic and electrical interface is the same as other established lifters in the company's portfolio.

Bin capacities from 120 litres up to 360 litres can be handled on either of the two chairs, which feature high tensile steel fronts, in a cycle time of eight seconds. Four-wheeled 'trade waste' containers between 660 litres and 1,280 litres capacity can also be handled.

Sensors identify this type of container and automatically link the hydraulics of both chairs to form one single lifter. In this mode, cycling time is still a respectable 10 seconds.

The lifting cycle is in two stages. Sonar sensors detect the bin as it is presented to the lifter and initiate a soft lift start.

Only when the bin is securely clamped does the lifter accelerate to optimum cycling speed. A tip angle of 50 degrees providing a hopper chute angle of 70 degrees ensures that tightly packed bins can be emptied easily.

Terberg says that low maintenance and whole life costs are particular attractions to end-users. The use of sonic sensors reduces the number of moving parts by eliminating pedal arms with springs, and proven lubrication free bearings and pins remove the need for weekly greasing. 'OmniDell' is backed by a four-year fully inclusive warranty.