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Removing Clogging Issues from Media Filters
Recycled Wastewater Treatment Plant
2nd November 2012 | filter cleaning
With the help of Envirofluid, the water corporation identified and mitigated a major health risk while reducing costs and improving cleaning results. It achieved this result by substituting dangerous products with safe ones whilst improving filter performance.
By replacing Chlorine with Triple7 Colloidal Concentrate, the Water Corporation has improved the health and comfort of their workforce. They have eliminated the health risks of the caustic blend and improved user safety and comfort.
The Water Corporation has benefitted from cost savings in terms of labour and downtime. The filters were requiring treatment with chlorine every 2 days, but were still working well 6 months after being treated with Triple7 Colloidal Concentrate. They are now also experiencing removal of the clogging material, boosting the filter effectiveness to near new capacity.
The Triple7 Colloidal Concentrate has improved sustainability at the Water Corporation sewage treatment plant along with improving filtration results, reduced costs, and improved worker health, safety and comfort.
& how we got there ...
Traditional cleaning products such as chlorine are effective bacteria killers. However, most do not go on to remove the bacteria from the surface being treated, which means the filter medium can remain clogged with particulate matter. It is this organic build-up that blocks most traditional media filters.
The Water Corporation in WA discovered the extent of the difficulty when a 6,000 litre Dynasand DST150 sand filter at one of its sewage treatment plants had a major problem with clogging. It had to be treated every two days, which involved adding chlorine to the filter, followed by an air sparge to disburse the chlorine and then a backwash. The chlorine kill approach was not only costly in terms of labour, downtime or chemicals, it failed to remove all the clogging material.
How do you efficiently kill bacteria in filters without causing dead cell build up and organic binding of media that results in clogging and poor filter performance?
Chlorine is toxic with corrosive properties.
Main Routes of Exposure of Chlorine is through inhalation, skin and eye contact. Some of the potential known health effects of Chlorine include:
- Skin Contact: Contact can cause irritation, pain, erythema, frostbite, blisters and burns.
- Eye Contact: Contact causes irritation and burns. Larger exposures can cause irreversible eye damage.
- Inhalation: Can cause severe irritation of the nose and throat, followed by coughing and wheezing, choking, dyspnea, sputum production and chest pain. Continued exposure can cause nausea, headaches, dizziness and central nervous system disturbances. Larger exposures can effect lungs, blood and body tissues leading to cardiac or respiratory arrest and even death.
Short-term high level exposures can also aggravate pre-existing heart diseases, producing electrocardiographic changes and congestive heart failure.
The Solution: Triple7 Colloidal Concentrate
The problem was successfully treated with Triple7 Colloidal Concentrate. The environmentally-friendly organic agent removes the food source on which the bacteria feed, which prevents colonisation. When added to backwash cycles, it causes the organic materials to separate from the media and boosts filter effectiveness to near new capacity.
The Water Corp added 10 litres of Triple7 Colloidal Concentrate to the filter flow at a rate of 1:600. The medium was first air sparged to enable the concentrate to work through the sand, then allowed to stand for 20 minutes before the backwash. Some six months later the filter was still working well. The authority was advised to dose the filter with Triple7 Colloidal Concentrate every 2-3 months or to add it as part of the backwash cycle at a rate of 1: 30,000 parts water.
Triple7 Colloidal Concentrate's cleaning formulation is built on three plant-based surfactants that create unique hydrocarbon release agents able to tolerate tremendous soil loads. The powerful micelle cleaning action causes long chain hydrocarbon soils to be repelled from the cleaning surface so that soils can be rinsed away with water.
This unique cleaning action will not damage the cleaning surface or react with other chemicals, so there are no dangerous by-products which could harm workers or the environment.