OBJECTIVES

• Maximize recovery of organic material and production of biogas, while minimizing the proportion of  inert materials and amount of biodegradable content sent to landfill.   
• Reduce downtime and maintenance costs, e.g. through the previous lack of material purity causing outages in digesters.
• Comply with product quality objectives. 
• Help La Rioja Eco-park meet its profitability aims.

SITUATION

The X-TRACT 1200 unit is a waste sorting system using the most advanced sensors on the market. These, with its high production capacity and short amortisation period, make the unit the most advanced and profitable available. Thanks to its X-ray technology, the system is able to identify materials regardless of their surface and separate substances according to atomic density. Its X-ray camera has a 0.8mm resolution, allowing it to detect and separate extremely small fractions of inert materials. The result is fast, efficient production of a highly pure, organic fraction, over 90% free of inert materials. Calculations by TOMRA, based on knowledge of how the x-tract unit has performed in diverse trials, have shown increases in biogas and electrical energy production of around 20%, compared to levels achievable before its development.

TOMRA Sorting’s separation systems are integrated and can be adapted to any existing facility, as is the case at the Eco-Park, where the X-TRACT unit operates in the pre-treatment line alongside other, conventional equipment. The X-TRACT 1200 unit at the Eco-Park works intensively in separating inert materials (such as glass, stones and metal) from the flow of organic waste which the plant processes. The unit leaves the latter at optimum purity, ready to be fed into the digesters, where the biomethanisation process takes place.

Thanks to the unit’s outstanding features and its self-protected design, the X-TRACT unit has gained special endorsement from the Spanish Ministry of Industry. It therefore requires no special authorisation to be installed or operated in Spanish territory.

BENEFITS

• The unit processes an average of 12 tons per hour. 
• It reduces the proportion of inert materials – higher than 15% at input – by about six per cent, signifying an organic fraction purity of around 94%. This indicates the system’s high efficiency, considering the processed fraction is not sifted and still contains the fine components. These figures also suggest a rise in the amount of biogas produced per input ton.
• This enhanced quality has brought other direct benefits, such as a decrease in maintenance costs arising from abrasion in components and materials, as well as an increase in digester operational time through longer intervals between outages for purposes such as cleaning.
  

"Our experience with X-TRACT has been highly positive."

Miguel Ángel López, head of the Eco-Park plant, said: “After three years in operation, our experience with X-TRACT has been highly positive. It has helped us reach our declared objectives because it enables us to guarantee the minimum quality required in the product obtained and thereby increase the overall performance of our process."

“The unit has achieved the main objective of guaranteeing a low amount of inert content in our output material, making it ideal to be used in the digestion process. Adaptation to the unit’s use was easy, as its handling and operating rules are fairly simple, as is its basic maintenance. We previously had problems in the digesters related to the decantation of inert materials in their interiors, which have been considerably reduced, so introducing this equipment has contributed to lowering maintenance costs and improving overall performance, by stabilizing our operation.”