TOKYO, Japan – Kurita Water Industries has released what it has called Japan's first continuous passing type one-step anaerobic ammonium oxidation (anammox) process.
It was developed by modifying Kurita's original nitrogen removal system for wastewater treatment.
The nitrogen treatment technology, based on the anammox reaction, is increasingly being applied to the treatment of effluent from semiconductor and chemical factories, wastewater treatment facilities, and dehydration and filtration in wet methane fermentation.
Kurita said the process can be used for the treatment of high flow wastewater with low nitrogen concentration.
The nitrogen removal system was developed using anammox bacteria in 2003, and put into a full scale system for a large semiconductor factory into operation in 2006.
After securing its first order for the one-step process in Japan, the company has now made the technology available.
Originally, the anammox bacteria were discovered by researchers at the Delft University of Technology in the Netherlands in 1990.
Kurita formed an alliance with Netherlands-based Paques to commercialise the denitrification method based on the anammox reaction in Japan under the name of the anammox process.
The one-step process refers to the anammox reaction for the partial nitrification of nitrite and nitrogen removal in a single reactor. The introduction of an original granulation technology in which a mixture of ammonia oxidizing bacteria and anammox bacteria is grown in a biofilm.
In addition, the continuous one-step process uses a reactor equipped with a special gas solid separator (GSS) that separates anammox granules, gas and treated water to carry out the nitrification of nitrous acid and nitrogen removal at the same time.