We all make sewage, but often give little thought to where it goes, how its treated, or even, how it can be recycled.
Sewage isn't just from the toilet. Waste water from your shower, bathtub, washing machine, dishwasher, kitchen sink and toilet is all considered sewage.
A typical 4-person household produces around 400–500 litres of sewage every day.
Liquid waste from business and industry is also part of the sewage stream. Industrial sewage is commonly known as trade waste.
Homes and businesses in Geelong produce around 50 million litres of sewage daily.
Sewage is 99.8% water.
Stormwater is not sewage.
Stormwater is rainwater that collects on your rooftop and street, and is usually collected in gutters and underground pipes. Stormwater typically travels through creeks and rivers to the sea.
Barwon Water does not treat stormwater. In our region, stormwater is managed by local councils.
Waste water from your laundry and bathroom is often called greywater. Greywater can often by reused immediately, for instance on your garden.
Waste water from your toilet is sometimes called blackwater. Blackwater is not suitable for domestic reuse without a dedicated treatment system.
"Sewerage" refers to the network: the sewerage system.
"Sewage" refers to the actual wastewater inside the pipes.
The sewerage system consists of the pipes, pumping stations and treatment facilities that collect and treat sewage.
Our sewerage system comprises 11 water reclamation plants, over 170 sewage pumping stations, and more than 2200 kilometres of sewage pipes.
We own and operate water reclamation plants in:
The Black Rock plant is the largest, and treats sewage from the greater Geelong region.
The Northern Water Plant, adjacent the Shell Geelong Refinery in North Shore, is the newest facility.
Under contract, we also manage (but do not own) the Barwon Prison wastewater treatment plant in Lara.
Our water reclamation plants reclaim water from sewage so it can be recycled or discharged with no negative impact on the environment.
Our plants use a mix of biological, chemical and mechanical processes.
Pre-treatment involves removing objects such as paper, gravel, plastics, bottles, nappies and most identifiable solids.
Naturally-occurring bacteria and other micro-organisms use the sewage as a food source.
This process reduces the amount of suspended solids and organic material by up to 98%.
Normal by-products are water and carbon dioxide.
Phosphorus and nitrogen are typically reduced by specialised microbes that break down nitrogen compounds into nitrogen gas and absorb phosphorus in their tissues.
To further clarify the treated water it may be filtered through a sand bed or through pores in a membrane.
Disinfection destroys pathogens (disease-causing organisms) that may be present in the treated water. Our plants use chlorine or ultraviolet light.
Treated, disinfected sewage is known as recycled water. Where possible, this recycled water is used for a range of purposes, including irrigation sporting grounds, tree lots and farms.
Excess treated water is discharged to the ocean via a submerged pipeline. (Excess water from the Colac Water Reclamation Plant is discharged to Lake Colac.)
We don't manage or regulate septic tanks (it's a local council function) but we do treat septic waste. Contractors pump out septic tanks and deliver the effluent to our reclamation plants for treatment.
Septic tanks require regular maintenance. We recommend you:
We may not accept poorly managed or contaminated septic waste.
For more information on septic tanks and how to manage your septic waste system, please contact your local council.