DigestivorePAD is a simple, easy-to-implement but a comprehensive solution to many common problems associated with biosolids management. Ovivo’s DigestivorePAD process consists of anaerobic digestion followed by post-aerobic digestion. Aerobic digestion, operating in conjunction with anaerobic digestion, provides enhanced volatile solids reduction, increasing performance by 20% to 30%. Increased volatile solids reduction results in reduced biosolids management costs and improved dewaterability of biosolids. DigestivorePAD uses anoxic and aerobic conditions in the post-aerobic digestion to create nitrification and denitrification environments. This results in more than 95% ammonia nitrogen removal and more than 90% total inorganic nitrogen (TIN) removal in the side stream. This is especially beneficial for utilities facing stringent nitrogen discharge limits. Almost complete removal of ammonia reduces the nuisance odor which is a common operational issue. DigestivorePAD also reduces the struvite scaling issues by removing a key component required for its formation, the ammonium content. Further, the post-aerobic digestion step strips sludge off CO2 and stabilizes the pH so that any struvite formed remains in the sludge. This results in significantly reduced phosphorous levels in the sidestream.

When can I consider DigestivorePAD™ Technology?


Anaerobic Digestion already in application?


Slidestream Treatment Installed?


Low sludge disposal costs



If the above are true for your application, DigestivorePAD™ Technology may be a good fit.

  • Reduction of Nitrogen without chemicals
  • VSS Reduction
  • Odor Reduction
  • Struvite Stabilization
  • Water Expert™ asset management and training tool



  • Involves placing aerobic digestion after anaerobic digestion with an internal recycle
  • Sludge Retention Time (SRT) in the Aerobic zone 2-10 days
When does DigestiveorePAD™ Technology make sense?

  • High biosolids management cost (>$53/WT)
  • Meeting Total Nitrogen/Phosphorus Effluent Limits
  • Struvite scaling formed in piping/pumps/dewatering equipment
  • Odor issues


* Data from Spokane County Regional Water Reclamation Facility (SCRWRF) Solids Handling report by CH2M / Every site is different and different assumptions affect the cost evaluation.  Contact us to get a personalized analysis for your application.

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