The results in all cases as expected showed a reduction in volume and large density increases. However it was the extent of the volume reduction that was of most significance. The overall total volume of all materials processed was reduced from 856m³ (Pre-shred) to 333m³ (Post-shred) prior to compaction.

The overall average percentage reduction of materials by 61% would highlight and recommend the use of slow speed shredding in this application where saving landfill space for the future, maximising cell capacity and reducing the reliance on landfill compactor operation/costs are the goals. In the caseof 7 Mile Waste Facility it is projected that the lifespan of the landfill would be extending from 2038-2054 (16 years) which itself, is a capital saving of approximately $7.8 million. The largest net earner from the process was the recovery of hidden ferrous metal from the general waste stream that traditionally have been lost.

The EDGE Slayer XL was able to recover between 5-8T/day. The equivalent of $18,000 per month. Another notable post shredding benefit included the ease of handling and future compaction, reduction in litter and reduction in rodent/bird interaction of the shredded material with a reduction in material cover required.

Morné Hattingh, Managing City Services – City of Karratha; “Choosing to upgrade an existing plant or designing a new facility to include shredding must be evaluated on a case by case basis to determine if the benefits are worth the additional capital investment and operating costs. Purchasing cost and Operational cost of a waste shredder may seem like a large increase but it should be kept in mind that by far the majority of the cost of operating a landfill facility is dedicated to paying back initial capital investment, which in our case, increase by less than 2% with the addition of shredding equipment.”

The next step in this process is to look at the what has not been measured and which will become the biggest peripheral benefit in the process of shredding at landfill is the savings realised from the reduced reliance on the landfill compactors.