Going underground: Could underground waste storage systems be the way forward?

Paddy Knowles joined the Solutions team at APSE in July 2015 as a Senior Consultant. Before that, he worked for 36 years in local government, with 25 years in waste collection and disposal. In one of their current projects, the team have been considering the potential advantages of underground waste storage systems over the traditional wheeled bin system.

Like many waste managers before me, I was sceptical about the value of underground waste storage systems; I thought they were expensive, difficult to install and undesirable to residents. Therefore, when I looked into this very different – and potentially controversial – area of waste collection, it was difficult to imagine that I would feel enlightened by my findings. Yet, with an open mind, I put my scepticism to one side and considered its potential ability to revolutionise our waste collection services.

Over the last 5 years, there have been a number of articles regarding the use of underground waste storage containers, as well as a number of studies and reports. For example, there was the recent National House Building Council Foundation (NHBC) report, which offers guidance for developers to alleviate what they call 'bin blight', highlighting ideas for good storage design as well as best practice examples for the UK house building industry. This included, amongst others, underground waste storage.

Underground bins are completely different from what we view as the norm in the UK and are at the opposite end of the operational spectrum from what we do now. There are some difficulties in installing this type of system in established housing developments but it is not impossible, although there is an initial capital investment required by local authorities to make this most significant change in the refuse collection services for decades. However, with the current easy access to low cost capital funding, I believe this is worth the pain and will deliver efficiencies for both the council and housing developers in the long term.

A new way of thinking

Ultimately, there is one question we should be asking ourselves; should we be thinking differently when it comes to dealing with our waste? This requires us to take a look at the work of our continental colleagues, who have been using this type of system for many years with great efficiency.

Widely used across mainland Europe, the amount of storage available in each container varies from system to system, with volumes normally ranging between 3,000 and 5,000 litres, meaning fewer bins are required than currently used; the 5,000 litre bin holds the equivalent of 20 wheeled bins. Access can either be open, with no restriction on who can use it, or restricted to a number of residents by the use of a swipe card, key pad or RIDF fob. It is recommended that a restricted system is used to reduce the risk of abuse by non-residents and in the case of recycling bins, to reduce the risk of contamination.

In the past, there has been some resistance to the UK using underground systems, but that is changing and a number of authorities have now installed them in established housing areas. Peterborough is a well-documented example of an authority that has introduced underground waste storage systems in any quantity into a number of its low density housing areas. There are also a number of local authorities encouraging developers to use these systems in new developments through planning guidance. Particularly where storage capacity is at a premium, these systems can free valuable above-ground space. Inner city areas can definitely benefit from these systems, and a number London Boroughs have already installed bins and actively encourage developers to look at them as a serious alternative to the large quantities of bins currently cluttering up storage areas or sited permanently on the street. For example, in 2011 the London Borough of Tower Hamlets completed the installation of 115 underground waste containers as part of a £250 million regeneration project for the area.

These systems are also fairly versatile, with a small number of authorities installing underground systems in much smaller projects. In Hastings, underground systems are used to effectively encourage and increase recycling in town centres. However, the bigger efficiency savings are gained through much larger developments, with the largest installation of underground waste containers in the UK being the North West Cambridge and Cambridge University project, in which an estimated 450 underground bins are currently being placed across a 150-hectare development site. The bins are collected and maintained by Cambridge City Council through a shared service agreement between Cambridge City Council and South Cambridgeshire District Council, using a new, specially-adapted collection vehicle.

Advantages and disadvantages

There are advantages and disadvantages to using underground systems. One of the main advantages is the immediate improvement of the adverse visual impact that thousands of bins left out on our streets. Just imagine what we could do with all the extra space that would be freed up by removing all the brick built bin stores or areas where bins are gathered.

Additionally, hiding the waste underground greatly reduces any potential disturbances to residents by reducing the potential noise impact from residents rolling bins back and forth, and through a reduction in odour as the waste is enclosed underground. The system could also potentially allow bins to be placed in locations where above ground systems might be considered unacceptable to the community, such as conservation areas and parks. An example of this is Princess Street Gardens in Edinburgh, where 200 litterbins were replaced by 16 underground units.

It is true to say, and certainly my personal experience, that when bins are consistently left on the street, they are much more vulnerable to vandalism, arson attacks and adverse weather conditions than if the waste was stored underground. In addition, if you don’t have the bins on the streets to be vandalised or stolen in the first instance, you don’t incur the cost of repairing or replacing them if they are.

There is also the issue of some residents regularly forgetting to put their bins out for collection and also issues around when they go on holiday; bins are missed as there is nobody there to put them out. With an underground system the resident never has to worry about missing the collection again as the bin is already out for collection.

It’s not all good news though, and no system is without its disadvantages. One of the main disadvantages of underground waste storage systems is the potential high cost which, if procuring a system as a single unit, would be considerable and the concerns justified. However, these types of systems are rarely installed in isolation and there are some possible economies of scale to be derived, which would need to be negotiated through any procurement process when looking at the implementation of a large number of units.

The evidence indicates that installing underground bins reduces the overall capital costs for the developer, which seems to be a bold statement. However, when you take into account that above ground bins are usually required to be placed in some form of storage facility, constructed at the expense of the developer, this doesn’t seem so bold. In fact, North West Cambridgeshire in their Sustainable Resource and Waste Management Strategy March 2012, indicated that the installation of underground bins would actually reduce the capital costs by around £734,000 based on the installation of 465 underground units over 155 locations, each unit being the equivalent of 20 x 240 litre wheeled bins.

Both underground and above ground bins require a degree of maintenance. The implications of maintaining wheeled bins, with the replacement of wheels and lids and even the whole bin, are well known to us. In the case of underground bins, maintenance tends to be in the form of a service once every twelve months (unless there is a significant structural failure of the unit).

The other major work involved in these systems is the groundwork required to install them on site. In new developments this tends not to be an issue as typically, there won’t be any existing services, however this may not be the case for a new development on, for example, old industrial land although in this situation any existing service would normally be disconnected and therefore pose no risk. However, on established housing estates services may need to be redirected, incurring additional costs.

As with all major infrastructure changes, one of the biggest issues will be the political and public acceptance of such a drastic change in direction and convincing people that this is the way forward may be very difficult – made more difficult by the increase in distance that some residents would be required to carry their waste to the new container; the recommendation is that no property should be further than 30 metres from its designated container.

Assisted collections could be an issue, although levels of assisted collections are quite small compared to the overall number of collections made. Essentially, carrying a carrier bag or pedal bin liner to the bin should be much easier for residents than managing a heavy wheeled bin. However, there would still be a requirement for assisted collection in some cases, and the management of this will need to be considered when introducing any scheme. 

Finally, the design of underground systems means that they are not compatible with the vehicles currently used to collect wheeled bins or sacks, and will either require the retrofitting of a Hi-ab or crane with some adjustment to the rear of the vehicle to accept the waste. This may, depending on the chosen system, reduce or completely remove its capacity to collect wheeled bins, or require the procurement of a specialist vehicle specifically designed for the purpose.

Potential efficiencies

I believe that there are good, sustainable efficiencies to be gained from the use of these systems. However, to maximise this potential there would need to be enough properties on the underground system to make up one or two weeks’ work (depending on the collection frequency). In terms of the round size, those for underground bins should be considerably larger, as each underground container will hold the equivalent of approximately 20 wheeled bins (depending on the size of unit chosen) and will take considerably less time to empty. Although a full round will maximise the efficiencies available, the system can still operate on a partial conversion, but the potential for any efficiencies will likely be reduced due to the difference in operations. Also, if the vehicle is to be fully utilised, this will require a vehicle that can accommodate both collection systems.

In addition to the efficiencies already highlighted, there is a potential 33% efficiency saving on staffing costs; rather than a standard driver and 2 wheeled bin crew, the maximum crew compliment required for the new system is two. This will, of course, depend on the operational planning of the route and the removal of any possible reversing situations. However, it should be noted that maximum efficiency savings can only be achieved by using a single operative, which actually isn’t an unusual practice with above ground bins. Many operators use a single operative to empty 1,100 litre bins, showing that it can be managed effectively.

Dependencies

There are a number of dependencies which should be recognised; the number of properties involved is important if maximum efficiency is to be realised. As such, this number should be seen as sufficient to form one complete round. Also, excellent communication is vital in order to ensure that residents buy into the scheme. Further, restricting access to the bins should be carefully considered to help reduce contamination in recycling bins.

Though not exclusively required, the use of fill level sensors in underground bins is an excellent way to control demand and will enable vehicles to only empty bins that are full, removing the requirement for a collection based on frequencies, and so maximising the capacity of the vehicle.

Conclusion

Personally, I have moved from a position of scepticism to realising the many benefits of underground waste storage systems. Moving from the current system would be a leap of faith, but I firmly believe that any authority with the long-term vision to improve their refuse, street cleansing or parks collection services, and with access to the capital funding required to move this type of project forward, will make efficiency savings – as will the developers who work with them.

The motivation for writing this article was a research project that APSE Solutions had been asked to carry out by a member authority. We were asked to produce documentation that would inform and offer supplementary planning guidance to designers and developers of new housing developments, in respect of waste storage options. The work was to specifically look at the potential of underground waste storage systems as a viable, compatible alternative to the current systems used.

As well as this, the Solutions team have produced a case study on this project, which can be viewed here. We would also be happy to speak to any authorities who are considering going down this route and would like assistance in developing their own guidance document.