ELOVAC® is a technology for vacuum degassing of digested sludge with an option for integrated phosphate precipitation - compact and ready to connect. This technology is particularly beneficial for all anaerobic digestion plants looking to reduce their environmental footprint. With the optional phosphate precipitation, ELOVAC® improves dewatering, saves polymer costs, reduces phosphate backwater and helps avoid struvite deposits.

Unique Benefits

Improving the carbon footprint

After the digester, the digested sludge still contains methane in dissolved form and in the form of micro gas bubbles. This methane, which is harmful to the enviroment, is released into the atmosphere during the sludge storage and dewatering of the digested sludge. ELOVAC®-P captures this gas which can then be used as biogas. This significantly improves the carbon footprint of the wastewater treatment plant.

Compact system with easy installation

ELOVAC® is supplied as a ready-to-connect, compact, skid-mounted system. This enables placement in a building or a container that can be set up flexibly on-site.

Improved dewatering with reduced polymer

Dissolved phosphate improves the water binding capacity of EPS and proteins (Kopp, 2013*), meaning there is an inverse relationship between the phosphate concentration in the sewage sludge and the dry matter content after dewatering. The higher the phosphate concentration, the lower the dry solids content. Therefore, precipitation of the phosphates leads to improved dewatering and reduced polymer demand. At the Lingen sewage treatment plant, for example, ELOVAC®-P has increased the dewatering result (DS(A) value) by more than 5 % points, saving approximately 20 % of disposalcosts.

Prevention of struvite scaling

Vacuum degassing removes CO2 from the digested sludge in addition to methane, thereby increasing the pH value. With the addition of magnesium chloride this creates the perfect environment for controlled phosphate precipitation. Microcrystals are formed which remain in the sludge and do not adhere to pipe walls, tanks and the dewatering aggregates. The pH value is only slightly increased. At the same time, the phosphate concentration drops significantly - and with it the risk of uncontrolled struvite deposits after ELOVAC®-P.

Improved quality of biosolids

Struvite is a long-term fertiliser with very high plant availability. When ELOVAC®-P is used, the struvite crystals remain in the dewatered sludge. This improves the quality of the dewatered sludge as an agricultural fertiliser.

The functional principle of ELOVAC®

  1. Sludge is fed continuously to the vacuum reactor tank.
  2. In the vacuum reactor tank, a vacuum pump withdraws the gas present in dissolved form and as gas bubbles from the digested sludge. The pressure and the amount of sludge in the vacuum reactor tank are controlled to predefined values.
  3. If required, MgCl2 is added to the reactor tank. Via vacuum degassing the pH increases. This results in the perfect environment for controlled struvite precipiation.
  4. The degassed digested sludge is continuously discharged from the vacuum reactor tank to the downstream sludge treatment stage, typically dewatering.

Footprint: Example of an ELOVAC®-P 20 unit

ELOVAC®-P - scalable fit for your requirements

See what customers have to say

Quote from Mr. Hüer, Management, treatment works of Lingen (EMS):

‘After implementing the vacuum degassing system with simultaneous phosphate precipitation: ELOVAC®-P, we no longer have problems with struvite scaling. With ELOVAC®-P we not only avoid operational problems, but also save on disposal and polymer costs.’


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Contact us

Maria Dittmann
Jahnstraße 36
88214 Ravensburg
Tel. +49 751 359785-14