Sydney has suffered a string of major droughts over the years, causing farmland to become parched and, in some cases, unusable. A recycled water proposal involving biosolids, however, is starting to change the lives of some Australian farmers.
According to Sydney Water, more than 40 farms from central to south-west NSW are now using biosolids to improve the quality of their soil. Many of these farms grow crops like barley, wheat, oats and canola, and biosolids are also used on pastures for goats, cattle, and sheep.
How the biosolids process works
Organic solids or “sludge” is a soupy material produced during the wastewater treatment process. Through proper production methods, sludge can be transformed into nutrient-dense biosolids.
Step 1: Thickening the sludge
Both chemical and mechanical methods are used to reduce the amount of water present in the sludge and transform it into a thicker material. Treatment plants use a number of different methods to do this including centrifuges, gravity thickeners, or dissolved air flotation.
Step 2: Sludge digestion
Both aerobic or anaerobic digesters can be used to break the sludge down in order to make it stable. Stabilising the sludge is done for a number of reasons:
- To reduce the pathogens present in the sludge
- To increase the availability of nutrients in the plants
- To reduce odour
Step 3: Dewatering
Belt machines or high-speed centrifuges are used to remove water from the biosolids. The weight of the biosolids is then reduced, making it easier for transport.
How biosolids are used on farms
The biosolids are applied to farmland and mixed into the soil prior to crops being sown. Once the crops have matured, the harvested parts of the crops don’t come in direct contact with the soil or the biosolids. Animals that graze on earth supported by biosolids are withheld for a specified time to ensure public safety.
Biosolids and safety
One question that people understandably have about biosolids is how safe they can be given that we are using waste products on our farms.
Biosolids are tested on a daily basis by the Environmental Protection Authority (EPA) to ensure their safety and stability. According to the EPA, for every 100 dry tonnes of biosolids tested, there is one sample taken.
Farms involved in the biosolids program are also rigorously tested on a regular basis to ensure the quality of the soil and to check for the presence of heavy metals.
How biosolids are benefiting the environment
The obvious benefit to using biosolids is that they reduce our environmental footprint. Through the use of biosolids, we:
- Minimise the amount of waste going to a landfill by recycling what has proven to be a valuable resource
- Reduce the amount of solid waste being deposited into our rivers and oceans
- Minimise the use of chemical fertilisers used on farms
- Biosolids are even being used to produce the gas that’s used to generate the electricity needed to power the biosolids treatment plants!
How to conserve water in your own home
JEDI Plumbing works with homeowners in the Sydney area to ensure that they are optimising their water usage through the use of properly functioning appliances and pipes. Apart from hiring a Sydney plumber to tend to your leaky taps and toilets, you can help save water in other ways, including:
- Saving cooled water from cooking to water plants and gardens
- Taking showers with a low-flow showerhead instead of baths
- Using a lower dishwasher setting
For more water conservation ideas or to speak to a professional Sydney plumber about your plumbing needs, we invite you to call us at JEDI Plumbing today on 0411 774 381.