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Updated: Aug 10, 2025
09:50
Electrochemically and Bioelectrochemically Induced Ammonium Recovery
Published on: January 22, 2015
12.8K
Study on ammonia generation from digested sludge by subcritical water treatment
Takahiro Kato1, K Kojima1, M Sumikura1
1Shimizu Corporation, 3-4-17, Etchujima, Koto-ku, Tokyo 135-8530, Japan t.kato@shimz.co.jp.
Summary
Subcritical water treatment recovers ammonia from digested sludge, converting solid and dissolved organic nitrogen. This method achieved an 84% ammonium generation rate, offering a valuable renewable energy source.
Area of Science:
- Environmental Science
- Chemical Engineering
- Renewable Energy
Background:
- Organic sludge is a potential renewable energy source.
- The nitrogen component of sludge is currently underutilized.
- Conventional ammonia recovery methods are limited to soluble components.
Purpose of the Study:
- To investigate subcritical water treatment for ammonia recovery from digested sludge.
- To optimize conditions for maximizing ammonia generation rate.
Main Methods:
- Digested sludge was treated using subcritical water.
- Key parameters varied included temperature, pressure, treatment time, and oxygen ratio.
- Ammonium generation rate was measured under different conditions.
Main Results:
- Subcritical water treatment successfully converted solid and dissolved organic nitrogen into ammonia.
- An optimal ammonium generation rate of 84.0% was achieved.
- Optimal conditions were 400 °C, 10 MPa, 5 min treatment time, and an oxygen ratio of 1.2.
Conclusions:
- Subcritical water treatment is an effective method for ammonia recovery from digested sludge.
- This process can utilize both solid and dissolved organic nitrogen.
- The findings contribute to the development of renewable energy from waste materials.
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