Article by Hardboss
In wastewater treatment, the effluent sewage stream is sometimes disinfected. Disinfection is accomplished, generally, by either using contact
chlorination, ultraviolet (UV) processes or by applying Ozone. Disinfection is generally required if the waste stream has the potential to come into contact with the general population, or drinking water supplies. The overall goal is to reduce the infection risk to the surrounding population.
The least expensive and most common type of disinfection is by chlorination. Generally, the wastewater stream passes over chlorine tablets (known as contact chlorination) which increases the chlorine concentration in the wastewater. The increased chlorine concentration is very effective in killing most harmful pathogens.
The second type of contact chlorination is a batch process. In batch application(s), the wastewater fills a large tank, where sufficient chlorine is added to kill most pathogens. In batch processing, the chlorine is added manually as a powder or as chlorine gas.
In sensitive areas, the chlorinated wastewater stream can be passed through de-chlorination tablet feeders to neutralize the chlorine prior to discharge. One disadvantage is that salts are introduced into the environment via the chlorination/de-chlorination process.
Ultraviolet disinfection (UV) uses no chemical in the treatment, and the treated water is not subjected to the salts produced in chlorination processes. One significant disadvantage is that the UV disinfection systems require constant maintenance and a power source. UV light bulbs or windows must be cleaned regularly and bulbs replaced.
Third type of chlorination method is Ozone. Ozone if a very effective and fast-acting disinfection method. Generally, the Ozone is produced onsite and is introduced into the waste stream. Ozone disinfection requires higher power supplies to run, but is relatively safe. Maintenance requirements complicates the Ozone process and its reliability.
We recommend using Chlorination tablet feeders and the applicable Chlorine tablets to disinfect most wastewater streams. We feel that the NORWECO Chlorine tablet feeders, and the NORWECO Disinfection tablets are the best on the market. Please visit our online store for pricing.