Updated: July 2002

1. Purpose

In recent years, reclaimed sewage has been used to supply ponds and streams in urban areas as a part of a multipurpose utilization program. The reclaimed water must be sanitary and safe for people to touch or even put into their mouths, when it is used for a city stream or pond. In response to those demands, Kobe Steel offers an "Advanced Wastewater Treatment System Using Low Pressure Reverse Osmosis" to produce clear, safe and sanitary water.

2. Performance

Water Quality (Example of Analysis)

3. Characteristics

1) The low pressure reverse osmosis membranes remove color, odor, BOD, COD, MBAS (measure of foam-causing substance), N, P, bacteria, viruses, etc. Thus, very clear, safe and sanitary water is produced. Both the appearance and sanitary safety of the water is almost equal to that of tap water.
2) The cost of operation is low because of the low operating pressure (below 0.98MPa) and the sim-
3) The quality of the reclaimed water is stable, in spite of fluctuations in the raw water quality (secondary treated water).
4) Maintenance is easy because the system maintains itself automatically.

4. Principle

1) Pretreatment
(1) The coagulant (PAC) and the sodium hypochlorite to control the slime are injected to the raw feed water.
(2) Suspended solids which can obstruct the reverse osmosis membranes, are removed bay two media filters which are arranged consecutively.

2) Reverse Osmosis Treatment
(1) The reverse osmosis module is the spiral type. The spiral type has many advantages such as compactness, easy exchange of membrane elements and high resistance against the suspended particles in the feed water.
(2) The membranes are washed with the reclaimed water automatically to prevent a decrease in flow of the water.

5. Subject

Streams, fountains and ponds for playing, bathing, keeping fishes, etc.
Sewage reuse system
Fire fighting water
Sprinkling of the streets or trees

6. Figure

Flowchart of the Advanced Wastewater Treatment Using Low Pressure Reverse Osmosis