From start to finish

Thessaloniki, a port city in the Macedonia region of northern Greece, is the second largest city in that nation. The temperature in the summer reaches 104 degrees Fahrenheit, and the region attracts many overseas and domestic tourists who stay at seaside towns along the coast. The city also attracts business people who hold meetings at venues such as the HelExpo Centre, which holds exhibitions and conferences year-round.

The responsibility for waste management in the city and the surrounding prefecture (also known as Thessaloniki) belongs to FODSA (Regional Association of Solid Waste Management Agencies of Central Macedonia), which is publicly owned and manages waste for the Association of Local Authorities of the Prefecture of Thessaloniki as well as for seven nearby prefectures. FODSA manages the treatment of waste for some 2 million residents overall.

Recycling is encouraged

FODSA widely encourages residents to recycle and reduce the generation of municipal solid waste (MSW) sent to the landfill. The group has provided blue 290-gallon containers for the collection of mixed recyclables, including paper; cardboard; ferrous and nonferrous cans; aseptic cartons; and polyethylene terephthalate (PET), high-density polyethylene (HDPE) and low-density polyethylene (LDPE) plastics. The blue containers are in communal collection points, next to similar-sized green containers for nonrecyclable MSW.

The city of Thessaloniki collects the mixed recyclables from the blue containers on behalf of FODSA using a fleet of 21-cubic-yard rear-loading collection vehicles made by Hephaestus Stefanou SA, Thessaloniki. The trucks, mounted onto Mercedes Axor and DAF chassis, are fitted with a bin lift with comb and trunnion arms that comply with standards for emptying the containers.

The collection service uses a driver and two additional workers. The collected containers are positioned at the rear of the trucks by the workers so they can be emptied by the vehicles’ lifting equipment.

FODSA also provides blue “igloos” to collect glass bottles and jars. These are spotted near hotels, multioccupant dwellings, restaurants and night clubs. The city of Thessaloniki provides a tipper truck with a crane fitted behind the cab to empty the igloos regularly. The system is designed to protect other recyclables from the abrasiveness of the glass.

Once the dry recyclables have been collected from the blue containers and igloos, the recyclables are delivered to a material recovery facility (MRF) in Sindos in Thessaloniki prefecture. The paper, cardboard, metal cans and the plastics are separated before being baled for shipment to processors. The mixed-color glass is delivered to a glass processor, where it is separated by color for melting and producing new glass bottles and jars. The reject material from the Sindos facility is baled and taken to the landfill for disposal.

FODSA says it helps the Thessaloniki region move its waste up the waste hierarchy, aiming to comply fully with the Revised Waste Framework Directive (2008/98/EC), the European Commission’s basic concepts and definitions related to waste management, to boost recycling and provide a closed loop system for recyclables, thus contributing to the circular economy.

FODSA also provides collection points at shopping centers, public buildings and offices for the collection of batteries for recycling, helping to comply with the Amended Batteries Directive (2013/56/EU). The collection of waste electronic and electrical equipment (WEEE), such as refrigerators, freezers and TVs, also is provided, helping the region comply with the WEEE Directive (2012/19/EU).

PUTTING MSW IN ITS PLACE

FODSA has organized a network of waste transfer stations for the discharge of nonrecyclable waste by the municipalities in the prefecture. The transfer stations are designed and sited to help reduce travel time for collection vehicles.

The prefecture’s main Finikas waste transfer station processes all the city’s waste. Built in 1995 with Netherlands-based Kiggen and Austria-based MUT, the facility is covered and sound insulated and has four static compactors that compress delivered waste into hermetically sealed roll-off containers. Vehicles discharge their loads into the four static compactors on the facility’s upper level, while the lower level is where the roll-off containers receive MSW falling from the top level into the hopper of the static compactors.

When waste collection vehicles arrive at Finikas, their loads are weighed and they are directed to one of four static compactor apertures for discharge. A traffic light system is used: green informs drivers they can reverse inside the waste transfer station to discharge their loads; red indicates they cannot discharge their loads because the roll-off containers receiving the waste at the lower level of the transfer station are either full or are being exchanged with an empty container.

The roll-off containers are positioned via a traverse moving frame on the lower level. Once a roll-off container is full, it is moved so an empty container can be positioned at the aperture and locked into place to continue loading.

Initially, the waste transfer station only processed waste produced in the city of Thessaloniki. The staff who manage and operate it are directly employed by the city. However, more recently, the city of Thessaloniki has agreed to allow other municipalities to deliver their waste in their own vehicles to Finikas, helping them avoid delivering MSW directly to a distant landfill.

Finikas is open 24 hours per day, 365 days per year, and the waste from the other cities arrives at nonpeak times.

FODSA also has organized waste transfer stations in other parts of the prefecture. FODSA operates a fleet of Renault Kerax and Iveco Trakker trucks that position empty transfer trailers under the loading apertures at these transfer stations to enable loading without interruption. The group also transports the full ejector trailers to the sanitary landfill site of Thessaloniki prefecture to be emptied.

A LANDFILL THAT CAN LAST

All the MSW in Thessaloniki prefecture eventually is delivered to the Mavrorahi sanitary landfill. The landfill site is operated by FODSA, which designed and constructed it to replace a sanitary landfill at Tagaredes that closed in 2007, after it had reached its full capacity.

Before the new Mavrorahi landfill site opened in 2008, civil works were undertaken, including a specially engineered road complete with a bridge for vehicles to travel across a ravine to reach the landfill. A special road network into and out of the landfill (for example, one road for incoming vehicles and one road for outgoing vehicles that have been emptied) also was constructed. Two scales were installed, one to weigh incoming vehicles and one to weigh the outgoing vehicles to establish their tare weights. The landfill was lined, and the necessary pipework was constructed to transport leachate and methane gas.

To ensure the waste collection and transfer system was not inconvenienced, FODSA allocated an area outside the landfill for Thessaloniki to deliver fully loaded roll-off containers to the landfill at night and on weekend afternoons. Thessaloniki provides several dedicated roll-off vehicles to empty containers inside Mavrorahi once the landfill is open.

Empty roll-off containers also are stored outside the landfill, so roll-off trucks delivering full containers of waste from Thessaloniki city to Mavrorahi on a 24-hour cycle can offload full containers and reload with empty roll-offs to take back to Finikas. This helps ensure the waste transfer station always has empty containers and waste collection and waste transfer activity at Finikas is uninterrupted.

Once waste collection and transfer vehicles have been weighed on the first weighbridge at Mavrorahi, they travel along the haul road to the tip face of the landfill to discharge their loads. The waste collection and transfer vehicles head to the second weighbridge at the exit of the landfill to obtain their weighbridge ticket before leaving the site.

The fresh waste deposited at the tip face of the landfill is pushed into the landfill cell by bulldozers for compaction by a landfill compactor made by Peoria, Illinois-based Caterpillar Inc. Bulldozers also spread soil excavated from near the landfill over the fresh waste so it is covered to prevent animals from intruding.

The leachate collected from inside the landfill is treated in an adjacent desalination plant. The desalination plant uses reverse osmosis technology and polishes the leachate to reduce the levels of biochemical oxygen demand (BOD), chemical oxygen demand (COD) and ammoniacal nitrogen in the leachate before it is discharged off-site.

Methane is flared off-site using a series of flare torches for the different landfill cells. The landfill site complies fully with the requirements of the EU Landfill Directive (1999/31/EC), according to FODSA.

CONSIDERING CONVERSION

Current FODSA President Michalis Geranis says he realizes Thessaloniki prefecture cannot rely on landfills as a long-term solution for handling MSW. Therefore, he says, FODSA is looking at energy-from-waste (EFW) as a longer-term sustainable solution to the problem.

FODSA says it is considering mass-burn systems as well as emerging technologies, such as gasification and pyrolysis. It is FODSA’S belief that by incorporating EFW into its longer-term waste management strategy, the prefecture will be self-sufficient in its own electricity needs.

Facilities also have the option of being tied into a combined heat and power system.

Geranis says FODSA is focused on providing sustainable recycling, waste transfer and sanitary landfill services for all of Thessaloniki prefecture (including landfill rehabilitation at closed landfill sites such as Tagaredes).

The group’s plans include further developing its waste transfer infrastructure via the construction of another waste transfer station, which will help reduce the carbon footprint and emissions from vehicles. Its plans for an EFW facility will help the prefecture provide renewable energy and become energy self-sufficient for decades, says Geranis.

The author writes about waste management topics and is based in the U.K.