Filtration and Treatment
AlburyCity's Water Filtration Plant, located in Water Works and Boundary Roads East Albury, supplies drinking water to residents in Albury as well as the southern villages of Greater Hume Shire.
Filtration Fast facts
- The water filtration plant operates 24 hours per day, 7 days per week.
- It can process 140 megalitres of water per day, or 56 Olympic-sized swimming pools.
The treatment process
Raw (untreated) water is pumped directly from the Murray River by one of three pump stations located directly opposite the water filtration plant, and approximately 1.3 kilometres and 4.2 kilometres upstream of the plant. The pumps are strategically located at these points on the river to ensure that pumps can draw the best quality water available at any particular time.
When the raw water arrives at the plant, it goes through the various treatment processes. Specific chemicals are added to improve water quality. For example:
- Powdered activated carbon is added to remove algal toxins and control the smell of the water by reducing the levels of methylisoborneol (commonly known as MIB) and geosmin.
- Alum (aluminium sulphate) and polyelectrolyte (a non-ionic polymer) are added to assist with the coagulation and flocculation process. Essentially, these chemicals cause the dirt particles to stick together so that it is easier to filter them out.
- Lime is added to remove the acidity caused by the alum.
- Fluoride is added to improve the health of teeth.
- Chlorine gas is used as a disinfectant to kill any microorganisms.
The water is then passed through a filter medium consisting of layers of gravel and sand, topped with a layer of anthracite (a hard filter coal), to remove dirt particles.
The filters must be cleaned every 8 to 24 hours depending upon the quality of the raw water. To clean the filters, clean water is pumped back through the filters to remove accumulated dirt. The backwash water is then discharged to one of the four sludge lagoons, where the dirt settles. The return water is then pumped back to the filtration plant and mixed with the incoming raw water. Approximately every 12 months, the lagoon is allowed to dry out and the dried sludge is either disposed of off-site or spread over the WFP grounds as topsoil.