Screening of green and organic waste with Hexpert

Complete sorting line, entirely designed by Ecostar, the case study of Ponikve Krk

This is the story of Ponikve eko otok Krk utility company in Croatia, which in 2020 decided to implement a complete sorting line – Ecostar’s Hexpert system – to treat the green and organic waste from the island of Krk.

Krk is the most populous island in the Adriatic Sea (around 20.000 inhabitants during the winter season) that had been having a waste management system since 2005, where waste is collected separately. In 2014, the whole system was upgraded to a door-to-door one, integrating the user responsibility scheme and the collective awareness of the locals, visitors, and tourists. Given this door-to-door system, the company was facing ever-growing quantities of biowaste (green and organic), around 5000 tons per year, collected in plastic bags, thus they needed a pre-treatment system to separate the biowaste from the plastic bags to have a clean material to then turn into quality compost.

Before the installation of the Hexpert sorting line, the separation process was difficult, time-consuming, and underperforming. Moreover, during peak seasons when the island is flooded by tourists (around 140.000), the quantities of material to be sorted increased dramatically so the waste was accumulating waiting to be processed, and beginning to ferment before the separation, thus leading to a difficult sorting process because of humidity.

The solution: Hexpert – Ecostar system for the treatment of the organic waste in Krk

In Ecostar, thanks to the Hexact modular screen and our team’s efficiency, we can develop turnkey solutions, designed according to the client’s available space and material to be screened. With Hexpert the operator can increase capacity and precision in the separation of waste and of the materials to be screened, significantly reducing investments in ancillary structures.

That was also the case of Ponikve waste management facility where in 2020 an Hexpert complete sorting line was installed to treat the green and organic waste of the island of Krk. The line comprises:

  • A bag opener, that straps the bags, without shredding and cutting the materials inside
  • Feeding conveyor
  • New Hexact 4000 dynamic disc screen Ø50+80 mm
    • Stationary electric version with screening surface 4.000 x 1.600 mm. with hexagonal discs in Hardox
    • The screener is equipped with an anti-clogging patented system
  • Steel support structure with maintenance walkway and stair
  • Magnet overbelt that is positioned crosswise over the conveyor belt for the separation of heavy ferrous metal pieces
  • Underscreen conveyor
  • Overscreen conveyor

Hexpert sorting line – the operations

Hexpert includes two different screening sizes and allows for optimal separation of organic material. Here are some of the characteristics of the Ponikve organic waste screening line:

  1. Capacity and waste characteristics: 10 t/h, 500-600 kg /m³ bulk density, 40-60% humidity.
  2. The waste is loaded in the hopper of the bag opener (that rips the bags).
  3. Opened bags containing organic waste are conveyed to the HEXACT screen.
  4. The screener separates the organic material resulting from torn bags from other unwanted waste, with an excellent degree of cleanliness.
  5. The lower screen fraction is treated by a magnetic belt separator to remove any metal objects.
  6. The lower screen material is made of approximately 90% of organic material, which is to be sent to the aerobic digestion process.

Here are a few of the advantages of the Hexpert sorting line installed by Ponikve.

  • The sorting line has a total installed power of 56 kW, with an energy consumption lower than 44kwh
  • The Hexact stationary screen is equipped with a 7.5 kW single-engine.
  • Hardox flat discs, meaning resistance in the long run.
  • DDS (Dynamic Disc Screening) technology, with an anti-clogging patented system
  • High quality of the fine fraction
  • Easy maintenance, translating into low maintenance costs

Hexact screenHexact screen

Today, the island of Krk benefits from a strong waste management system, where household green and organic waste is being treated and separated from other materials and sent to the aerobic digestion process. This small community, thanks to its locals and municipality is today an example of “yes, we can” to the rest of the country, waiting for its tourists this summer as it is fully ready and equipped to successfully handle the entire waste of the island.

If interested to know more about our turnkey solution Hexpert do not hesitate to get in contact, one of our managers will offer you all the necessary information.

Organic waste screening with Hexpert
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