JPH02284689A - water sterilization method - Google Patents

Abstract

PURPOSE:To sterilize water without using an oxidizing agent-based fungicide such as chloride by impressing a high-voltage pulse with specified electric field strength and pulse width on the water to be sterilized. CONSTITUTION:When a high-voltage pulse is impressed on the water contg. bacteria, the electric energy is impressed on the cell walls of bacteria and transduced into mechanical membrane compressing energy, hence the cell walls of bacteria are broken, and the bacteria are destroyed The electric characteristic of the high-voltage pulse necessary to break the cell walls of bacteria differs to some extent depending on the kinds of bacteria and the amt. of an electrolyte in water. However, the water can be almost surely sterilized by controlling the electric field strength to 10-50kV/cm and the pulse width to about 100-1000musec. Since a chemical is not used in this method, the method is advantageously applied in sterilization especially when pure water is produced. In addition, as this method is not affected by the reducing matter dissolved in treated water and pH, sterilization is surely achieved even when the water quality is fluctuated.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for sterilizing water.

[Conventional technology]

Tap water is generally water from rivers, lakes, and marshes that has been purified at a water purification plant. Raw water collected from rivers etc. contains about 10,000 to 5o, ooo bacteria/+al and 1,000 to 10,000 bacteria/1001
It is common for water to be contaminated with about 111 E. coli bacteria, but most of these bacteria are removed through coagulation and sedimentation and rapid filtration treatments at water treatment plants. However, in order to purify beverages until they pass the general beverage criteria, which states that the number of bacteria should not exceed 100 in 1 ml and coliform bacteria should not be detected in 1015 bottles or in 1 50 melons, chlorine, It is common to sterilize by adding sodium hypochlorite, ozone, etc.

However, even if oxidizing agents such as chlorine are injected into water for the purpose of sterilization, if there are many reducing inorganic substances (Fel, Has, etc.), organic substances other than bacteria, ammonia, etc., they will have priority in oxidizing them. It gets consumed. In addition, the bactericidal effect is
Affected by light and pH. Therefore, the sterilization efficiency of sterilization using oxidizing agent disinfectants varies significantly depending on water quality, etc., and it is important to control the amount of disinfectant injection. In addition, recently, the carcinogenicity of organic chlorine compounds produced by the reaction between chlorine and organic substances has become a problem.

[Problem to be solved by the invention]

Therefore, an object of the present invention is to provide a method for sterilizing water without using oxidizing disinfectants such as chlorine.

[Means to solve the problem]

In the water sterilization method according to the present invention, the electric field strength of 1 is applied to the water to be sterilized.
0-50 KV/caa, pulse width 100-1000P
This is characterized by applying a high voltage pulse of See.

[Action of the invention]

When high voltage pulses are applied to water containing bacteria, electrical energy is applied to the bacterial cell walls, which is converted into mechanical membrane compression energy that ruptures the cell walls and kills the bacteria.

The electrical characteristics of the high-voltage pulse required to destroy bacterial cell walls vary somewhat depending on the type of bacteria, the amount of electrolyte present in the water, etc., but the electric field strength is approximately 10 to 50 KV/cm, and the pulse width is approximately 100 to 1000 μSee. It was confirmed that many bacteria can be almost certainly sterilized by using this method.

The method of the present invention is suitable for sterilizing not only water supply water but also water that cannot be shaken by adding disinfectants, such as pure water for experiments or industrial use, and is suitable for use in various experimental facilities, medical facilities, factories, etc. It is also useful for sterilizing wastewater containing microorganisms discharged from etc.

〔Effect of the invention〕

Since the sterilization method of the present invention does not use any chemicals as described above, it is a sterilization method that is particularly advantageous for producing pure water. Furthermore, since it is not affected by reducing substances dissolved in the treated water or pH, the sterilizing effect is reliable even when the water quality fluctuates.

〔Example〕

Raw water collected from a river was subjected to coagulation and sedimentation treatment using sulfuric acid clay, followed by rapid filtration treatment, and then high voltage pulse treatment under the following conditions.

Applied voltage: 20 KV Pulse width: 200 pSec Pulse interval: O, 1 Sec Electrolytic strength: 20 KV/e Treatment time = 5 seconds Table 1 shows the results of examining the number of bacteria on the water before and after the treatment.

Table 1 Number of general bacteria before treatment After treatment (number of bacteria/10ml) 650 20 Coliform bacteria (number/100+ml) 30 0 Agent Patent attorney Itai ~ Oboro

Claims (1)

[Claims] A method for sterilizing water, which comprises applying a high voltage pulse having an electric field strength of 10 to 50 KV/cm and a pulse width of 100 to 1000 μSec to water to be sterilized.