Updated: July 2002

1. Introduction

Chiyoda Corporation has made a great effort for the conformity with the environment in the worldwide projects.
In the chemical and petrochemical plants, various kinds of wastewater are released, such as oily wastewater, organic wastewater, and nitrogenous wastewater as shown in the figure below.
To treat these wastewaters, it is necessary to use various treatment technologies in combination. Some of the key technologies for combination are listed below.

2. Key Technologies

Biological treatment
- Chiyoda Biofiner (Including denitrification)
- Conventional activated sludge
- Activated sludge with submerged membrane filter
Physical and chemical treatment
- Chiyoda High Rate Filter
- CPI (Oil separator)
- Chiyoda Thoroughbred 242 (Activated carbon)
- Membrane filtration
- Coagulation/sedimentation
- Flotation

3. Total System

On top of the optimal combination of various key technologies, optimization of upstreams such as production processes in order to minimize the waste loading is also very important.
Furthermore, installation of water reuse systems and heat recovery systems using heat pumps can provide more economical facilities with less impact to the environment.

Example of a wastewater treatment system in petrochemical plant