With an ever-increasing global focus being placed on maximizing resource recovery and minimizing the amount of waste being disposed of in landfills, councils and waste management authorities around the world are changing the way in which they view their waste streams. This is particularly true in terms of the Municipal Solid Waste (MSW) stream. Once considered little more than the ‘useless’ fraction that remained following the removal of all of the ‘valuable’ and easily recyclable items, there has been a paradigm shift in the status of MSW – from burdensome waste to valuable resource.
Together with underlying financial incentive to minimise disposal at landfill, there are also significant environmental incentives. Landfill space is at a premium. The cost of managing and maintaining landfills (both in the short and long term) has risen significantly over the past decade, and these increases are reflected in the cost of disposal. Put simply, every ton of waste disposed of in a landfill carries a significant financial impact, and this will continue to increase as years go by.
From an environmental perspective, one of the largest drivers behind the reduction in the amount of MSW being sent to landfill is ‘Waste to Energy’ technology. In an effort to reduce their carbon footprint by reducing their reliance on energy from traditional generation sources, councils and authorities around the world are now turning to MSW as a reliable fuel source for ‘green’ electricity generation. By utilising MSW for electricity generation, ‘Waste to Energy’ technologies can provide substantial environmental benefits, including: reducing the amount of waste being sent to landfill; a reduction in CO2 equivalent emissions from decomposition of the waste; and a reduction in CO2 emissions resulting from coal-fired electricity generation.
Another major catalyst in the increased value now being placed on MSW is the recognition that; while it may not currently be viable to separate and extract all valuable component resources from the MSW stream, in the future, we may develop the technology to achieve this. Rather than categorising the current disposal stream as waste, it is now considered a possible future resource stream that can be ‘mined’ and utilised as technology becomes available and viable.
Importantly, even though the drivers behind the changing attitudes towards in MSW are many and varied, they all share one common theme, viz: If MSW is to be considered as a resource rather than a waste stream, there must also be some fundamental changes in the way in which it is handled, transported and stored. Richard Harris, managing Director of Sierra international explained:
“In recent years, one of the biggest changes for MSW in the global marketplace is the way in which the material is handled and stored.”
“Whether the intention is to use the MSW for ‘Waste to Energy’ applications or to preserve it for possible future processing and separation of specific component resources, ensuring that the material is kept in the best possible condition for future use is now a major consideration for an ever-increasing number waste management authorities, councils and contractors,” he said.
In addition to the above, there are immediate cost savings that can be realized through baling. These include operational benefits as well as public relations benefits.
The most important benefit is improved density of the material set in the landfill. The in-place density can be as much as 50% greater than those reached by compactors. This benefit will show up in extended landfill life and a smaller working face - less daily cover. If the baler are not wrapped, daily cover is usually reduced from 6” to 2” saving valuable air space as well as material and handling. If they are wrapped daily cover could be eliminated entirely.
The need for expensive compactors can be replaced by smaller front-end loaders, reducing replacement, fuel and maintenance costs. Compactors have a life of 5 plus years while balers can be in service well past 10 years.
Litter and vermin problems are greatly reduced when the material is baled into tight, dense packages. This can eliminate the need for liter barriers around the facility.
Methane production systems are easier to install in the neat rows formed by the bales. The better the methane collection system - the more gas that can be collected.
Tipping is moved from the working face to an all-weather surface, reducing the opportunity for injuries or death to workers and damage to the collection vehicles.
Macpresse offers a complete line of fully automatic, horizontal, single ram balers specifically designed to handle the harsh MSW environment.
The most common method of protecting the MSW for future use is bale and wrap the material. Compacting MSW into bales makes the material significantly easier to handle and store, when compared to loose material. Wrapping the bales not only helps to ensure that MSW is protected from damage or degradation caused by the unwanted ingress of moisture (from rainfall, etc.), it also helps to ensure that the material is fully-contained, thereby preventing issues such as wind-blown litter, odours, vermin, and/or problems associated with waste materials working loose and falling from the bale.
“With that in mind, when it comes to wrapping MSW ‘square’ bales, it’s important to ensure that the bale wrapping process has been specifically designed to minimise the risk of material being dislodged or the bale falling apart during the wrapping process,” he added.
In order to address these issues, German-based waste equipment specialists PTF Häusser GmbH has developed a range purpose-built bale wrapping machines that have been specifically designed for use with Municipal Solid Waste baling operations. Marketed under the brand Rotowrap, these remarkable units have already helped to revolutionise MSW baling and wrapping operations for numerous councils, waste management authorities and contractors through Europe and Asia.
Rotowrap units are available in a choice of five ‘fixed’ installation models (ranging in capacity from 10-20 bales per hour through to 55 bales per hour) together with an additional mobile bale wrapping unit which can be easily moved between processing locations.
One of the keys to the success of the Rotowrap units, is the speed and ease with which they carry out the baling wrapping process. By offering a range of models with a variety of processing capacity, they have the flexibility to match all throughput capacities – from the smallest rural/regional operation, through to the largest metropolitan MSW processing facility – without slowing the baling process down. Indeed, as the name infers, the Rotowrap 60 is capable of wrapping up to 55 bales per hour, thereby ensuring that it has the capacity to prevent unwanted processing ‘bottlenecks’.