Gist-brocades N.v.

Paques B.v.

Arnold Mulder

Rene Weltevrede

A biological denitrification is provided in which ammonium ion is used as an electron donor in the denitrification. The process may advantageously be used under conditions of high ammonium ion concentrations in waste water or to remove ammonium ion from manure, soil or surface water. Microorganisms are described which may be used in these processes.

Anoxic ammonia oxidation

Reduction of the hysteresis effects in a gaslift loop reactor is effected with a draft tube for solids suspension. The gas or liquid flow rates for generating complete solid suspension are significantly higher than the flow rates necessary for maintaining that state. These hysteresis effects may be significantly reduced and a substantial reduction is obtained for the energy necessary to obtain the state of suspension. Preferably a draft tube which comprises openings through which an extra circulation takes place especially during the startup phase is used.

Startup openings in a three-phase gaslift loop reactor

Waste water containing sulfate and organic material is purified by anaerobic biological waste water treatment where at least 80% of the sulfate is converted into hydrogen sulfide in an acidification process and at least 70% of the resulting hydrogen sulfide is removed from the waste water.

Anaerobic purification of waste water containing sulfate and organic

A novel process for the purification of waste water and/or waste water sludge comprising subjecting the waste water and/or waste water sludge to first a methane fermentation step, then a denitrification step and finally an oxidation step by aeration, the electron donor in the denitrification step being mainly the sulfide from the methane fermentation step and the remaining reduced compounds in the liquid effluent from the methane fermentation step being oxidized in the aeration step.

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Delft, Netherlands

Arnold Mulder