Industrial Material Division
Groundwater Membrane Filtration System

The groundwater membrane filtration system is a water purification system that reduces municipal water charges and provides safe, delicious drinking water. Itochu Enex recommends installation of the system at hotels, hospitals, schools, food plants, and other facilities that use large amounts of tap water.
This system is like a private waterworks. First, a miniature water purification plant is constructed on the premises. Groundwater pumped from a deep well is stored in a raw water tank and then purified by filtration through a sand filter and an activated carbon tower. Subsequently, the water is further filtered through a hollow-fiber membrane, chlorine is introduced for sterilization, and the water is supplied to a processed water tank. The result is clean, safe drinking water.
The use of a private water supply system makes it possible to reduce municipal water charges, a fixed expense, by 20% to 30%. Further, the system offers disaster preparedness benefits in addition to economic efficiency and incorporates a remote monitoring system to ensure safety.

Overview of a Groundwater Membrane Filtration System (Miniature Water Purification Plant)

1.A deep well is drilled to supply groundwater that is stable in quality and quantity.
2.Subsequently, a miniature water purification plant is installed on the premises to purify the groundwater.
- (1) The groundwater is filtered to the level of ordinary drinking water using a sand filter and activated carbon tower.
- (2) Advanced water purification treatment is performed using a hollow-fiber membrane with 0.1-micron pores.
3.Switching from municipal water supply to highly purified groundwater makes it possible to reduce municipal water charges.
4.Concurrent use with municipal water avoids risk associated with system failure or groundwater shortage.

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System Features

The groundwater membrane filtration system has three key features.

Safety: The system satisfies the water quality standards (50 items) stipulated in the Water Supply Act. Contaminants ranging from minute microorganisms to bacteria are completely eliminated.
Economy: There is no charge for groundwater itself. Although the system entails facilities operating costs and maintenance charges, savings of approximately 20% to 30% of current municipal water charges can be realized.
Disaster Preparedness: The system can contribute to the local community as an emergency drinking water supply source.

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Case Example of Benefits of Installation (Hotel)

Installation Examples

Plants	Heavy use of drinking water at a food plant and at a plant equipped with employee cafeterias and shower rooms
Hotels	Heavy use of water for showers and banquet rooms of a hotel with more than 150 rooms
Hospitals	Heavy use of water at a hospital with more than150 beds that performs dialysis

Economic and Installation Requirements

Annual municipal water charge	¥15 million or more (rule of thumb)
Installation space	Around 30 m² in the vicinity of the water receiving tank

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Maintenance and Emergency Response

Thorough, reliable periodic maintenance and emergency response ensure customer peace of mind.

1.Daily checks
- The facilities manager measures the residual chlorine concentration and performs a visual check of color intensity and turbidity.
2.Monthly checks
- A maintenance company technician performs periodic checks, cleaning, and chemicals replenishment. The technician draws a sample of processed water and sends it to an inspection agency designated by the Minister of Health, Labour and Welfare, which conducts analysis to confirm whether or not it meets water quality standards.
3.Emergency response
- When an abnormality occurs within the system, the remote monitoring system automatically initiates emergency processing.
  - 1) The maintenance company is notified.
  - 2) The system is completely shut down, and simultaneously water is drawn from the existing municipal water supply.
  - 3) A maintenance technician visits the site and performs work to restore the system.

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Water Quality Safety (Water Quality Standards under the Water Pollution Control Act)

"Isn't groundwater contamination a reason for concern?"

Groundwater contamination is caused by the intermixture of contaminated water or domestic wastewater from ground level. Since ordinarily a deep well approximately 100 meters deep is drilled and water is drawn from beneath two to three impermeable layers, there is no penetration of contaminated water near ground level.
Advanced water purification also ensures a supply of water that completely satisfies the water quality standards (50 items) stipulated in the Water Supply Act, shown in the table below.

New Drinking Water Quality Standards (effective April 1, 2004)

No.	Substance or criteria	Permissible value (i.e., must not exceed)	No.	Substance or criteria	Permissible value (i.e., must not exceed) or range
1	Standard plate count	100 per 1 ml	26	Total trihalomethanes (Total of Chloroform, Dibromochloromethane, Bromodichloromethane and Bromoform)	0.1mg/L
2	E. coli	Must not be detected	27	Trichloroacetic acid	0.2mg/L
3	Cadmium	0.01mg/L	28	Bromodichloromethane	0.03mg/L
4	Mercury	0.0005mg/L	29	Bromoform	0.09mg/L
5	Selenium	0.01mg/L	30	Formaldehyde	0.08mg/L
6	Lead	0.01mg/L	31	Zinc	1.0mg/L
7	Arsenic	0.01mg/L	32	Aluminium	0.2mg/L
8	Chromium (VI)	0.05mg/L	33	Iron	0.3mg/L
9	Cyanide ion and Cyanogens chloride	0.01mg/L as Cyanide	34	Copper	1.0mg/L
10	Nitrate and Nitrite	10mg/L as Nitrogen	35	Sodium	200mg/L
11	Fluoride	0.8mg/L	36	Manganese	0.05mg/L
12	Boron	1.0mg/L	37	Chloride ion	200mg/L
13	Carbon tetrachloride	0.002mg/L	38	Calcium, Magnesium (Hardness)	300mg/L
14	1,4-dioxane	0.05mg/L	39	Total residue	500mg/L
15	1,1-Dichloroethylene	0.02mg/L	40	Anionic surface active agent	0.2mg/L
16	cis-1,2-Dichloroethylene	0.04mg/L	41	(4S, 4aS, 8aR)-Octahydro-4,8a-Dimethylenaphtalene-4a(2H)-ol (Alias: Geosmin)	0.00001mg/L *1
17	Dichloromethane	0.02mg/L	42	1,2,7,7 - Tetramethylbicyclo[2,2,1]Heptane-2-ol (Alias: 2-Methylisobolneol)	0.00001mg/L *2
18	Tetrachloroethylene	0.01mg/L	43	Nonionic surface active agent	0.02mg/L
19	Trichloroethylene	0.03mg/L	44	Phenols	0.005mg/L in terms of Phenol
20	Benzene	0.01mg/L	45	Organic substances (Total Organic Carbon, TOC)	5mg/L *3
21	Chloroacetic acid	0.02mg/L	46	pH Value	5.8 – 8.6
22	Chloroform	0.06mg/L	47	Taste	Not abnormal
23	Dichloroacetic acid	0.04mg/L	48	Odor	Not abnormal
24	Dibromochloromethane	0.1mg/L	49	Color	5 degree
25	Bromate	0.01mg/L	50	Turbidity	2 degree

*1, 2.Until March 31, 2007, the value for both of these items (41 and 42) was 0.00002mg/L.
*3.Until March 31, 2005, the value for TOC (item 45) was 10mg/L.

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Site Preparation and System Installation

Site preparation and system installation work is performed in the following sequence. Around 60 to 120 days is required from the start of well drilling to system delivery.

We perform an advance survey of the ground and water source at the well site and propose installation only for projects that satisfy water quality and quantity requirements. In the unlikely event that the water quantity or quality of a drilled well are not as planned, the customer bears no cost.