Modern reject treatment systems for deinking and industrial recycled paper grades

Every recycled fiber processing line needs proper water, sludge, and reject systems in order to operate economically. The first goal is to minimize costs for resources, such as water and energy; the second is to minimize disposal costs.

Rejects and other by-products are often valuable and can generate income. For instance, metals have value as raw materials and plastics as a source of energy. Rejects from recycled fiber processing require proper treatment. It must be cost-efficient and simple, as well as fulfilling certain requirements to ensure that the rejects or their component parts can be re-used, sold, or disposed of at minimum cost and effort.

Depending on the intended purpose of the rejects, the major single operations are:

• Shredding
• Ferrous and non-ferrous metal separation
• Heavy particle separation
• Reject compacting
• PVC separation
• Sludge dewatering
• Drying
• Pelleting or combustion

These unit operations must be combined and arranged correctly to achieve maximum benefit.

Benefits of the reject treatment system

• Compliance with the legal requirements for environmental protection (e.g. landfill directives)
• Reduction of disposal and transportation costs by up to 30%
• Pre-treatment of rejects for fuel generation
• Reduction of greenhouse gas emissions (CO₂) by between 25 and over 40%
• Additional income from recycling of raw materials (e.g. metals and plastics)

ANDRITZ reject compactor (ReCo) – efficient dewatering of fibrous rejects

ReCo is a robust screw press for dewatering fiber-containing rejects. This press is especially designed for rejects from horizontal drum pulpers and conventional pulping systems to obtain the highest possible dryness in the rejects. The final dryness depends on the reject material (especially the fiber content) and the counter-pressure selected.

Benefits of the reject compactor (ReCo)

• High reject discharge consistency of up to 70%
• High filtrate quality, low suspended solids content
• Operational safety, reverse mode in case of blockage
• Trouble-free handling of large particles