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M-35: Diatomaceous earth spent filter cake recycling: Waste or a resource?

A. R. WELFORD (1); (1) EP Minerals, Reno, NV, U.S.A.

Sustainability II
Saturday, June 7 - 10:00 a.m.-11:45 a.m.
Level 3, Crystal Room

Historically spent-cake recycling was primarily driven by financial implications, but now, with rising public awareness of global warming, carbon reduction targets in many countries, and the sustainability of products being used as best practice, as well as as a sales tool, the need to reduce, recycle, and/or re-use by-products produced on site is high up on most sites’ lists of priorities. EP Minerals, LLC has taken an active role in supporting our customers to help them find and use fully auditable, local recycling operations. Using a project plan, detailed analysis in certified laboratories, and meetings with the local regulators, we have set up full-scale trials and been able to independently measure the benefits of using spent cake in these recycling operations. With compost, a 10% addition of spent cake mixed with shredded yard debris and food waste reduced the ammonia content of the compost by nearly 1,000 mg/kg, while still achieving the regulatory requirements and producing a market-quality product. With land application, by working with an independent agronomy company and running extensive replicated trials, over 10 acres in size, we were able to identify the maximum economic return point for application rates—2,500 lb/acre in this particular instance. The above work has allowed highlighting of greenhouse gas emission reductions from 205 MTCO2E for one small customer to over 9,000 MTCO2E for a large processor. With this background recycling work completed, we are now looking at the viability of various re-use options with full knowledge of all the regulatory and engineering hurdles involved.

Andrew Welford has been studying and working in agriculture, in both practical farming and as a qualified agronomic advisor, and in the waste industry for more than 20 years. He has been working for EP Minerals in his present global role for nearly two years. He has independently set up and managed land application, compost, and anaerobic digester operations, as well as being director of operations at a large hazardous waste transfer and treatment facility in the north of the United Kingdom. He has worked directly and indirectly with many of the breweries in the United Kingdom on recycling and managing various waste streams that are produced on site.

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