Portimao, the delightful holiday destination in the Portuguese Algave, now has another feature that is increasingly likely to attract visitors from elsewhere in Europe and indeed other parts of the world. In addition to being famous for the many top quality golf courses in the area - and its climate of course - Portimao is noteworthy for how its municipal waste and recycled materials is collected.
Having initially tried conventional wheeled bins and containers, ranging in size from 240litres (for individual households) to 1100litres (for shops and apartment houses), EMARP, the municipally-owned company established to run waste collection services in the city, has switched to the Sotkon underground system. Designed and manufactured in Portugal, the Sotkon System uses precast concrete silos in which a single cubic metre container is located just below the surface of the ground. Each silo features a hydraulically-damped hinged metal lid, which is only raised when the container needs to be emptied. At all other times, only the simple waste materials 'receptor' (the size of an ordinary litter bin) is visible above the surface.
In Portimao, typically a 'nest' of four silos is used in each location - one container for each individual waste stream. Each receptor is clearly labelled to ensure residents only put the correct designated material in each one. This could be paper/cardboard, glass, plastics, and residual waste in residential areas, or in more specialised applications the same standard units can be used for specified foodwaste, organic greenwaste, cans - or indeed, any other combination.
The advantages of going underground? In Portugal, there are considerable issues relating to the high summer temperatures, which encourage rodents and flies around open containers. To overcome this
- or the ingress of rainwater into containers - the Sotkon system is effectively sealed. High summer temperatures also create operational problems - to a point where it is physically stressful to work during the middle part of the day. Unfortunately, the solution - night collections - causes disruption to residents trying to sleep.
Considering the population of the town more than doubles each season due to tourists, the noise of traditional metal waste containers being emptied is just about the last thing the local department of tourism needs. The solution?
As WMW vehicle and plant correspondent, Malcolm Bates was recently able to establish, the Sotkon System has that issue solved as well - Sotkon waste containers are made from a rubberised plastic that enables them to be lifted from their silos during late evening and early morning shifts without any disruption from noise. Each standard refuse collection vehicle is fitted with a simple hydraulic loader crane, designed to lift the containers and place them in line with the otherwise standard bin lifter (which can also be used to empty 1100litre containers).
The whole operation takes just a few minutes per container which, considering the operational and environmental advantages, more than justifies any initial disruption incurred in excavating and installing the silos, according to EMARP waste operations director Luis Barbosa Fernandes. EMARP is planning to further increase the use of underground containers for both garbage and recyclable materials later this year.
How the system works in detail - and the operational and economic advantages - are explained in a major article by Malcolm Bates in the forthcoming May/June issue of Waste Management World.
*More information from www.sotkon.com
