Incredible Minerals Today

Recycling Diatomaceous Earth Spent Cake from Filtration into a Fertilizer

Posted by Julie Brown

Dec 4, 2013 5:05:00 PM


9000 tons diverted from landfill. Significant reduction in GHG emissions.

In the American Heartland of Iowa, agricultural crops and their subsequent processing make up a significant percentage of the state’s output. Landfill in the state is nearing capacity, and the cost of compliance to ever onerous environmental regulations is steadily increasing. Agricultural experts were looking for a new, cost effective, sustainable and environmentally-friendly solution that would satisfy the regulatory requirements and work in "their" conditions. Today’s growers want "hard proof" that a product has been tested under field conditions similar to their own. EP Minerals director of sustainability Andrew Welford worked with Iowa agricultural experts to plan and implement a trial to recycle the diatomaceous earth spent cake from filtration into fertilizer with significant results.

"By carrying out a detailed documented trial with agricultural application industry experts, we have shown that spent cake can move up the waste hierarchy from landfill through recycling to eventual re-use and highlight the fact that spent cake is potentially a resource not a waste."  Andrew Welford Director of Commercial Sustainability, EP Minerals


  1. Recycle DE spent cake rather than send to landfill
  2. Low cost of landfill
  3. Requirement to prove agricultural benefit of DE spent cake
  4. Establish independent crop growth trials
  5. Identify and develop a working relationship with an agricultural supply company


  1. Achieve regulatory compliance
  2. Lower/remove total cost of waste disposal
  3. Produce a quality fertilizer product
  4. Detail the benefits of using the product
  5. Produce a product with added value
  6. Move DE spent cake up the waste hierarchy initially to recycling and then up to re-use


  • Lower and eventually remove cost of disposal
  • Produce a DE spent cake fertilizer with a marketable value
  • Fully auditable and environmentally compliant recycling/re-use route achieved
  • Identify optimum application rate
  • Identify Maximum Economic Return

The results from the trial were surprising and paved the way for recycling spent cake into fertilizer as a standard for the Iowa agricultural industry

Waste diverted from landfill: 9000 Tons

  • Reduction in GHG Emissions: 9215 MTCO2E

For more information on this case study and to learn more about recycling DE spent cake, please email us at

Topics: Recycling and Sustainability


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Incredible Minerals Today gives readers insights and information about new exciting uses for diatomaceous earth, perlite and clay around the world today, plus the latest information about EP Minerals. 

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