DeSah: Techniques

UASB reactor

In the UASB reactor, organic material is converted into biogas by bacteria under oxygen-free conditions. In this way, considerable energy savings are made as no aeration is required. Furthermore, sludge production is very low and green energy is produced. The Upflow Anaerobic Sludge Blanket (UASB) process is a widely used method in the biological treatment of concentrated wastewater streams.

DeSaH has considerably simplified the UASB reactor enabling small reactors to be built cost effectively. The smallest reactor is only 1000 L, but of course (much) larger reactors can also be built. The UASB process is used for the treatment of various concentrated waste water streams.

Advantages of the UASB reactor:

  • already available in small volumes
  • very efficient removal of organic matter
  • biogas production, a renewable energy source
  • well insulated, reduction of heat demand
  • corrosion-free design
  • fully accessible for inspection and cleaning
  • closed system: no odour emissions  

OLAND

The OLAND (Oxygen Limited Autotrophic Nitrification) process is a cost-effective and sustainable way to remove ammonium from wastewater. Compared to conventional biological processes, this process leads to operational cost savings of up to 60%, while significantly reducing the amount of sludge to be drained.
With traditional nitrogen removal, more oxygen is needed in order for all ammonium (NH4+) to be converted to nitrate (NO3-) by using oxygen. In the OLAND process about half of the ammonium (NH4+) is converted to nitrite (NO2-) and Anammox bacteria convert the ammonium and nitrite into nitrogen gas.

DeSaH uses a Rotating Biological Contactor (RBC, also known as a bio rotor) for the OLAND process and has greatly improved the reactor design in order to be able to use the OLAND process on a small scale. The smallest reactor is only 500 L, but of course (much) larger reactors can also be built. The OLAND process is used for the treatment of various nitrogen-rich wastewater streams.

Advantages of the OLAND reactor:

  • already available in small volumes
  • very efficient nitrogen removal
  • well insulated, reduction of heat demand
  • modular
  • fully accessible for inspection and cleaning
  • easy process control

Struvite reactor

The struvite reactor is used for the recovery of phosphate from concentrated wastewater streams as struvite. Phosphate is becoming scarce which makes recovery increasingly interesting. Struvite precipitation is a cost-effective technology compared to, for example, the addition of iron salts, mainly due to significantly cheaper chemicals consumed and because the residual product has a positive value rather than being a major cost item.
The struvite produced is an excellent slow-acting fertilizer for N, P and Mg. In the struvite reactor magnesium (Mg2+), phosphate (PO43-) and ammonium (NH4+) or potassium (K+) are converted into struvite. By adding magnesium oxide (MgCl), phosphate and ammonium precipitate as struvite (MgNH4PO4.6H20 or MAP).

DeSaH uses an upflow reactor for struvite precipitation and has adapted the reactor design to make it suitable for small quantities of waste water. The smallest reactor is suitable for processing 200 L/d, but of course (much) larger reactors can also be built. Struvite precipitation is applied for the treatment of various phosphate-rich (50 mg/l PO4-P) wastewater streams.

Advantages of the struvite reactor:

  • good quality struvite
  • struvite of the same shape as fertiliser granules
  • already usable for small quantities of waste water
  • easy process control