Waste collection and transfer Thessaloniki - Greece

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1 Waste collection and transfer Thessaloniki - Greece BY TIMOTHY BYRNE The City of Thessaloniki is the second biggest city in Greece, with a population of one million people making Waste collection and transfer a very important task. The city is on the coast and receives thousands of tourists each year both stopping in the city, as well as visiting from neighbouring tourist destinations, such as Halkidiki. The waste collection service is operated twenty four hours a day, seven days a week and 365 days a year with staff able to choose either to work Christmas Day or New Year s Day. The city council provides 660 and 1100 litre containers for wastes; positioned at communal collection points along the roadside. In the inner 1

2 city where there are many residential apartments, the city council calculates the number of residents per apartment block, and then supplies the number of containers for the volume of waste estimated to be produced. Thessaloniki operates four collection shifts: early morning, mid morning, afternoon and night. The collection vehicles used are rear loaders with lifting equipment fitted to them to lift litre DIN type containers. Each vehicle is manned with a driver and two loaders, who place the containers at the rear of the collection vehicle to be emptied by the vehicle s lifting mechanism. Once empty, the containers are returned to the collection point by the two operatives. The collection vehicle moves onto the next collection point, with the operatives standing on the rear steps of the collection vehicle. Each collection vehicle collects two full loads a day. The majority of collection vehicles are of two axles and vary in capacity from cubic metres with payloads varying from five to eight tonnes. Thessaloniki also has several three 2

3 axle waste collection vehicles of 22 cubic metres capacity for use in collecting waste in the long streets in the central part of the city as well as its perimeter. The payloads from these larger vehicles are around twelve tonnes. Once the collection vehicles are loaded they return to the city council s depot at Finikas which is near the airport. At the depot a waste transfer station is operated to process all waste from the city. The transfer station was constructed in 1995 and has a closed roof. It has three static compactors of the Kiggen PD TSP11 type. The plant can process 900 tonnes of waste a day, with the possibility of the installation of a fourth compactor which will give a daily throughput of 1200 tonnes per day. The transfer station is operational 24 hours a day, seven days a week and 365 days a year. On arrival, the collection vehicles are weighed on the weighbridge at the entrance of the depot. Once weighed, the collection vehicles go to the transfer station, 3

4 where the plant manager instructs them into which compactor to discharge their load. There are traffic lights on the front of the three unloading bays. Green means the compactor is ready to accept waste but red means the roll on off container on the static compactor is being changed so the compactor is not available to receive a fresh consignment of waste. The collection vehicles reverse into the building to the static compactor they have been told to use. The waste collection vehicle lifts it hopper, clears the hopper of waste with the compaction mechanism, and discharges the load. Once discharged, the vehicle moves forward clear of the compactor. This is so the driver can lower the tailgate away from the edge of the compactor to prevent an accident. The waste is compressed by the compactor into 20 cubic metre hermetically sealed roll on off containers which can hold twelve tonnes of waste. Once the container is full, the transfer station operatives move the container on a traverse 4

5 moving frame to the right to await collection. Then a fresh container is moved by the operatives from the left on the traverse moving frame to the aperture of the static compactor for reloading. All of the full containers are collected by a roll on off vehicle of three axle configuration. The roll on off vehicles also have a drawbar trailer of two axle configuration so that they can transport two containers giving a combined payload of twenty four tonnes of waste each journey to the Mavrorahi sanitary landfill outside of the city. Once the roll on off has lifted a full container it is dismounted onto the drawbar trailer. All containers are secured with cross locks to prevent them coming loose on the journey to the landfill. The second full container is loaded onto the roll on off prime mover. The driver connects the trailer hitch to the roll on off prime mover and engages the trailer brakes to make sure that the braking system for the trailer is working properly before leaving the depot for Mavrorahi. 5

6 The landfill is to the north-east of the city and is an hour s drive away. The Mavrorahi sanitary landfill opened in 2008 when the older sanitary landfill in Tagarades closed. The site treats waste from central Thessaloniki and the prefecture which is delivered to site by both waste collection and transfer vehicles. The site is open seven days a week from 7am until 5pm Monday until Friday and from 7am until 1.00pm Saturday and Sunday. Because Thessaloniki collects waste twenty four hours a day, arrangements have been made with SOTANTH, the operator of the landfill, to store the roll on off containers full of waste at a storage area outside the landfill during the night. These are emptied in the morning by three slave roll on offs that the city council send to Mavrorahi from Finikas. The vehicles work on site all day emptying the full containers delivered at night as well as lifting the full containers off the trailer of the roll on off drawbar vehicles delivering during the day. This speeds up the turnaround for the driver of the drawbar roll on off thus improving productivity, 6

7 so that he can return to Finikas with two empty containers for the transfer station more rapidly. The drivers of the slave vehicles work two shifts from 06.00am until 12 mid day and from 12 until 5.00pm. The second shift of drivers drive their cars direct to the landfill to start their shift. This saves the drivers from the first shift returning their vehicles to Finikas then being driven to Mavrorahi by the second shift of drivers. This maintains productivity of the roll on off vehicles at the landfill site. On arrival at Mavrorahi all drawbar roll on off vehicles disengage the drawbar trailers leaving it parked outside the landfill near the container holding area. The roll on off prime mover heads down the landfill haul road to the weighbridge. The access roads are one way for entry and exit. The vehicles payload and gross vehicle weight are recorded at the first weighbridge. The roll on off vehicle heads onto the landfill where its load is discharged at the tip face. Once empty, the roll on off heads up the haul road towards the second weighbridge, where the driver 7

8 collects his weight ticket. The second container will have been collected by one of the slave vehicles and its load discharged onto site. The driver of the roll on off reloads with empty containers in the container storage area, re secures his containers and trailer braking system then heads back to the waste transfer station at Finikas. The container collected by the slave vehicle from the roll on offs trailer will be stored in the holding area for another roll on off drawbar to collect when making another journey to the landfill. When the slave vehicles finish at 5.00pm they are parked outside the landfill by the container storage area for the next day s shift. On Saturdays and Sundays when there is only one shift used, the slave vehicles return to Finikas with empty containers to make sure the transfer station has enough empty containers to deal with the volumes of waste processed over the weekend. The Mavrorahi sanitary landfill complies with standards set by the European Union landfill directive 1999/31/EC. The landfill extracts methane using a flare torch. The leachate is collected in lagoons and purified on site. 8

9 In conclusion, the City of Thessaloniki operates a sustainable waste management system for both residents and tourists. The productivity levels are very high for both the collection and transfer of waste, giving the community a sustainable waste management system for many years to come. 9