Wastewater treatment is the process of removing contaminants from wastewater, including household sewage and runoff (effluents). It includes physical, chemical, and biological processes to remove contaminants, producing an environmentally safe fluid waste stream (treated effluent) and solid waste (treated sludge) suitable for disposal or reuse (usually as farm fertiliser).
We have wastewater treatment plants in Atherton, Malanda, Ravenshoe, Tinaroo and Yungaburra. All other towns operate on septic systems.
Wastewater treatment generally involves three stages — primary, secondary and tertiary treatment.
- Primary treatment temporarily holds the sewage in a quiescent basin where heavy solids can settle to the bottom while oil, grease and lighter solids float to the surface. The settled and floating materials are removed and the remaining liquid may be discharged or subjected to secondary treatment.
- Secondary treatment removes dissolved and suspended biological matter. Secondary treatment is typically performed by water-borne micro-organisms in a managed habitat. Secondary treatment may require a separation process to remove the micro-organisms from the treated water prior to discharge or tertiary treatment.
- Tertiary treatment allows reintroduction into natural waterways such as rivers or streams. Treated water is sometimes chemically or physically disinfected prior to discharge into a waterway, or it can be used for the irrigation of a golf course or park.
Trade waste is liquid waste discharged into the sewer that is generated by industry, small business, commercial enterprises, clubs and organisations including charities, commercial kitchens, laundries, hairdressers, workshops, medical facilities, fruit packing sheds, accommodation places, kennels etc.