Esmil  Industrial Group and our Partner Esmil have gained vast experience in the fi eld of digestate treatment. From bench scale studies, right the way through to full scale size plant we strive to off er BAT (Best Available Technology) using state of the art membrane separation and dewatering processes.

Process Description

Our digestate treatment system consists of 3 major process units and is able to produce a dry solid
cake and a highly quality treated water suitable for process reuse or disposal and a high nutrient concentrate.

The first stage in our digestate treatment process is the separation of the solid and liquid fraction, otherwise known as digestate dewatering. For this we employ our highly effective Multidisc Screw Press Dehydrator  which with the assistance of a small dose of flocculant is able to remove the majority of solids from the liquor (sludge volume reduction of 6-10 times) and produce a dry cake with a dry solids content up to 40%.

For the second stage, we use special vibratory membrane technology – VSEP (Vibratory Shear Enhanced Processing). This effectively works in the challenging feed conditions.

Although the MDQ is able to remove the majority of the dry solids, some will remain along with other soluble contaminants. The dry solids may cause serious issues for standard membrane systems as they are highly susceptible to fouling. VSEP technology however, vibrates the membranes causing high shear forces at the membrane surface, greatly reducing the risk of fouling. Expected water recovery in this stage can be between 65-80%.

Our final stage of digestate treatment is a spiral-wound reverse osmosis membrane technology. This acts as a polishing stage further treating the permeate (treated water) from the VSEP units. Results have shown that a 95% reduction in COD concentration and 98% reduction of Ammonia can be achieved over the 2 passes of membrane treatment.

Technological stages were tried and are used on different ad plants:

• 2013 – Kurana UAB, Grain Bioethanol, Lithuania (VSEP, RO)
• 2018 – Renergy Inc., Wastewater Treatment Plant, USA (MDQ)
• 2018 – Quasar Energy Group LLC, Municipal Sludge, USA (MDQ)
• 2018 – KB BioEnergy Inc., Wastewater Treatment Plant, USA (MDQ)