Despite improvements and lower costs in alternative disinfection systems such as hydrogen peroxide, ultraviolet light and ozone, chlorination continues to be the most common method used for disinfection of home well water systems.
Chlorine bleach has been used as the primary means to sanitize potable water supplies since the beginning years of the 20th century and is even now the most popular disinfectant utilized in water treatment. Home well water chlorinators are favored because they are lower in cost as well as simple to install and operate.
No one likes to drink or bathe in water smelling like chlorine bleach though, and fortunately chlorine can be removed after the water has been treated with low cost carbon filter. So it is simple to have sanitized yet chlorine-free water through the entire home.
To be effective at killing bacteria, eradicating odors as well as treating iron, chlorine will need to have ample time after it comes in contact with the water to be effective. Generally for disinfection a minimum of 10 minutes of contact time is recommended, but this varies depending on the water chemistry, temperature and the level of chlorine being injected.
The Three Types of Chlorinators
There are three main types of chlorinators used in home well water applications:
1. Metering pumps using liquid chlorine bleach
2. In-Line Chlorine Solid Pellet Feeders
3. Well Pellet Drop Feeders
Simple to set up as well as low in expense, metering pumps are the most popular approach to chlorinating well water. The chlorine pump is installed so it switches on and off as soon as the well pump switches on and off, simply by wiring the chlorine metering pump to the current well pump pressure switch. In some cases a flow switch or a flow sensor is used, that is activated if there is a flow of water. The metering pump turns on and off depending on flow of the water.
With these types of chlorinators common household bleach which is 5% chlorine, or liquid swimming pool bleach which is 10% chlorine, is commonly used. A plastic solution tank holds the chlorine bleach solution and the metering pump draws the chlorine bleach liquid solution straight from the solution tank and ‘meters’ the chlorine at a controlled specific volume, inserting it in to the water pipe. The injection point is located before the pressure tank to be effective. The quantity of chlorine in the water, called the “chlorine residual” is simple to maintain and keep at a precise level when metering pump chlorinators are used.
In some instances, the injection point has to be located after the pressure tank. In this kind of installation the flow of the water varies, therefore a variable speed chlorinator should be used. This type of chlorinator has a flow meter and senses the speed at which the water is flowing and dispenses chlorine according to the flow rate.
It is important to use a contact tank with liquid chlorination systems to allow sufficient time for the chlorine to work.
In-Line Pellet Feeders
Another type of chlorine for home systems comes in solid pellet form. This type is 70% calcium hypochlorite and is a very powerful form of chlorine. The pellets can be utilized inside chlorinator called “erosion feeders”. In these types of chlorinators, a small portion of the pellet dissolves in the water as the water flows thru feeder. These types of chlorinators do not require electricity to work and therefore are the cheapest price of the three types of chlorinators. They are simple to manage and can frequently work for several months before the feeder needs more pellets.
In-line feeders do have a disadvantage, as the chlorine residual is hard to regulate. Generally the chlorine level is often too high immediately after these kinds of feeders, so a contact tank as well as carbon filtration is essential otherwise the water will smell and taste like chlorine bleach. There are some home well water applications where these pellet feeders work great though and they are easy to operate.
Pellet Drop Feeders
This kind of chlorinator uses a pellet feeder that runs when the well pump is operating and slowly drops pellets down into the well at defined time intervals. The rate at which the pellets are dropped can easily be regulated by the homeowner. Solid pellet feeders are helpful for controlling iron bacteria and hydrogen sulfide in well water, but are not typically used as a principal method of disinfecting well water. Like the in-line pellet feeders, the chlorine residual can often be difficult to manage. Another problem can occur when too many chlorine pellets are dropped the chlorine is often corrosive causing damage to the well and pump.