Mitsubishi Heavy Industries Limited

Mitsubishi Heavy Industries Engineering, Ltd.

Aqua Systems Limited

Naikai Salt Industries Co., Ltd.

Hideo Iwahashi

Yoshiaki Ito

Katsunori Matsui

Kazuhisa Takeuchi

Kenji Tanaka

Kiichi Tokunaga

Hidemasa Kakigami

Masayuki Tabata

Takeshi Yasunaga

Yuta Hashimoto

Masahiro Kishi

Takayoshi Hori

Yasuhide Gouda

This water treatment system is provided with: a reverse osmosis membrane device; a biofilm treatment device that has a carrier, on a surface of which is formed a biofilm, and that treats water to be treated before the water to be treated is transmitted through the reverse osmosis membrane device; and at least one of a water to be treated stoppage period circulation means and a water to be treated stoppage period supply means that are driven when the intake of new water to be treated is stopped. The water to be treated stoppage circulation means supplies and circulates water to be treated from a water to be treated discharge outlet side of the biofilm treatment device to a water to be treated supply port side. The water to be treated stoppage period supply means supplies new water to be treated to the biofilm treatment device.

Water treatment system

An object is to provide a pretreatment device of seawater capable of growing and maintaining a biofilm in a good state on each of a plurality of filters connected in series, by supplying nutrients appropriately to the filters. A pretreatment device of seawater is used in removing salt from the seawater to obtain freshwater, and includes: a supply duct () through which the seawater is to be supplied; a plurality of filters () including a particulate filtering material and a biofilm; connecting tubes () which connect the plurality of filters in series; a plurality of bypass tubes () each of which connects corresponding one of the plurality of filters to the supply duct; and a plurality of regulating valves () each of which is disposed in corresponding one of the plurality of bypass tubes to regulate a flow rate.

Seawater pretreatment device

A desalination apparatus includes a pretreatment devicehaving a pretreatment membranethat filters suspended matters in raw waterwith added chlorine-containing water, a reverse osmosis membrane devicehaving a reverse osmosis membranethat removes a salt content from filtrate watersupplied from the pretreatment deviceto produce permeated water, and a reducing-agent injection devicethat neutralizes the added chlorine on an upstream side of the reverse osmosis membrane device. The reducing-agent injection deviceextracts a partof the filtrate water, adds metering SBS solutionto the part, obtains a maximum change point (equivalence point) of the oxidation-reduction potential of a reducing agent and chlorine, obtains reducing-agent additive concentration (Csm) corresponding to the equivalence point, and supplies the SBS solutioncorresponding to the concentration to the filtrate waterto thereby neutralize the chlorine.

Desalination apparatus and desalination method

An embodiment of the present invention includes: a recycle line that brings a part of salt-enriched membrane separation concentrated waterback to the rear flow side of a pretreatment apparatus; a water discharge line that discharges the remained concentrated water into a sea area; and a control apparatusthat controls to adjust the ratio between the discharging amount of the discharging membrane separation concentrated water to be discharged into a sea area and the supplying amount of supplying seawater. A pH is set to be equal to or less than 7.3 by adding acid. The saltis obtained from the dryer, and produced water (fresh water)is obtained by combining evaporated watersupplied from the evaporatorwith the permeated watersupplied from the reverse osmosis membrane apparatus

Co-producing apparatus for salt and fresh water and co-producing method of the same

A high-pressure pump Pthat increases the pressure of raw water, a high-pressure reverse osmosis device including a high-pressure reverse osmosis membrane for concentrating a salt content in high-pressure feed water, a first drain valve mounted on a permeated water line for supplying the permeated water downstream and temporarily draining permeated water of an initial start-up from a discharge line, a low-pressure pump that is mounted on a permeated water line provided downstream of the first drain valve and reduces the pressure of the permeated water, a low-pressure reverse osmosis device including a low-pressure reverse osmosis membrane for concentrating a salt content in low-pressure feed water, and a second drain valve mounted on a discharge line at the concentrated water side of the low-pressure reverse osmosis device that temporarily discharges the low-pressure feed water of the initial start-up supplied to the low-pressure reverse osmosis device.

Multi-stage seawater desalination apparatus and operation control method of multi-stage seawater desalination apparatus

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Tokyo, Japan

Hideo Iwahashi