The Six Most common Reasons An Ozone Water Treatment Systems Fail

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The Six Most common Reasons why Ozone Water Treatment Systems Fail

Introduction

Ozone water treatment systems are used for a variety of applications. Nearly 1. 6 thousand gallons of city and county drinking water is treated with ozone. Almost all bottled water has ozone added prior to the bottling step. A number of fruit and organic washing operations, for ready to eat foods, use ozone to keep the food safe from bacteria and other pathogens. It is important that the ozone systems in these applications work reliably.

Knowing what forms of things can go wrong can help municipalities and industry make better decisions regarding the type of ozone water treatment system to buy and why various features are important. In this article we are referring to municipal/industrial scale ozone generators. We covers the six most common reasons why ozone systems fail, techniques for preventing these problems and proper instrumentation that can provide an early warning of potential problems.

Ozone Water Treatment Systems

Ozone water treatment systems take oxygen or dry air and convert the oxygen present into ozone. dental ozone treatment This ozone is then combined with water for the specific water treatment application, e. grams. disifection. There are a number of factors that can cause these systems to fail. This article tries to group them into six categories. Commercial scale ozone generator cannot accept water entering the generator without having severe damage. The potential for back flow exists since the gas must flow from the generator into the water, so there is a walkway for water to back flow into the generator. This is compounded because ozone can be being injected, via a venturi, into water that is at a higher pressure than that inside of the ozone generator. If there is a problem with the operation of the venturi or some change in the downstream hydraulics, water can be forced into the generator.

It's quite common to see check valves used to stop the back flow of water, but check valves are not the best device for this purposes, especially given the severe damage that can result from back flow. Check valves in this application have a high probability of failure. Most high quality ozone water treatment systems use a numerous barrier approach to back flow prevention employing several passive and active devices to detect and counter the trunk flow of water.

An example might be check valves, liquid draws in and differential pressure monitoring interlocked with a normally closed solenoid control device. Monitoring differential pressure is based on the fact that in normal operation the pressure in the generator must exceed the pressure at the point of hypodermic injection, otherwise the gas would not flow into the water. Triggering a solenoid control device to close eliminates the walkway for the water to reach the generator. Using a normally closed control device means that even with a loss of power, the control device is closed and the generator protected.

Another technique that is used is to place instruments in the gas line or liquid draws in that can detect liquid water. They can be used to trigger the shutdown of the solenoid control device and the generator. Without such protection it is usually a matter of time until some circumstances arises that causes the trunk flow to occur and damage the ozone generator.

Poor Feed Gas Quality

Ozone generators require a source of oxygen to make ozone. Ozone is simply three oxygen atoms connected together (O3). The air that we breathe contains about 21% oxygen, and is built from two oxygen atoms (O2). You can purchase pure oxygen from industrial and medical gas suppliers. It is also possible to make oxygen using a so called oxygen concentrator. Small versions of these devices are used for home medical purposes. They also produce a gas that is extremely dry which is 90-95% oxygen.

Different ozone generators have different optimal gas nourishes. Some generators work best with pure oxygen, other require some nitrogen being present (1-4%). Other generators work from dry air. In all cases the gas feed must be extremely dry. This is normally measured as the dew point of the air, the temperature at which water in the air will condense. For ozone generators this value is typically around -100 degree F. This means that there are only a few parts per million of moisture in the gas stream.

Moisture in the feed gas can lead to the formation of nitric acid in the generator creating the conditions for severe rust. In addition, moisture also reduces the efficiency of the ozone formation reaction, reducing output.

To insure that the feed gas is the proper quality oxygen monitors that report the concentration of oxygen in the gas can be used. Dew point monitors, hygrometers, are available that can measure the amount of moisture in a gas stream. They are often used in larger ozone generating systems.