Project details
- 01 September 1999
01 July 2003
Delft University of Technology; Ecco Tannery Holland B.V.; Shell Global Solutions International B.V.; Heiploeg B.V.
Senter
Western Europe
Research and Development
Effect of Salinity on Biological Nitrogen Removal from Saline Industrial Wastewater in Activated Sludge Systems
Ambitions and Achievements
The project concentrates on establishing fundamental relationships between salinity, pH, temperature and ionic strength on the kinetics of nitrification.
The research concept is based on a close and direct connection between the theoretical and experimental work at IHE and the practical problems in operation of industrial large-scale treatment works of the industrial partners.
The aim of the project is to generate an understanding, based on laboratory scale experiments and modelling, of the sensitivity of the nitrification process to sub-optimal salt concentrations in combination with other sub-optimal environmental conditions expected to occur in full scale treatment plants.
Background of Project
There is an increasing concern for the future availability of fresh water of good quality, which is leading to a policy of more economic use of water and water reuse. This will result in an increase of salt content of the ultimately produced wastewater. On the other hand, effluent criteria are becoming more stringent esp. with respect to the discharge of nutrients like nitrogen.
These two developments may interfere because high salt levels may negatively affect nitrification, which is the rate-limiting step in biological nitrogen removal. This means that there is a need for clear understanding of the precise effects of salt on the nitrification process. Therefor a research project has been set up.
This research project focuses on nitrogen removal in activated sludge systems used for treating saline industrial wastewater. A team of three industrial partners (Shell, Heiploeg and Ecco) and two knowledge partners (IHE and TUD) are involved in the project. The project was initiated at IHE with partial support from Shell on March 1998.
The official project subsidised by BTS/Senter started on 1/9/1999 for a period of three years.
Approach and Activities
Two phases are involved in the research project. The first phase incorporates laboratory scale and field-work research, the second phase covers the modelling part of the research topics. The main research topics can be summarised as follows:
- Determination of the qualitative and quantitative effect of the salt level on nitrification.
- Determination of the effect of different type of salt on the nitrification activity.
- Identification and quantification of the effects of salt in combination with other destabilising factors (pH and temperature) on the stoichiometry and kinetics of nitrification.
- Investigation of shifts in the microbial populations of nitrifying micro-organisms as a result of the prevailing salt level.
- Incorporation of the salt effect on nitrification in the existing activated sludge model (ASM 2).
- Considering the effect of salinity on technological and physico-chemical parameters.