Developing a comprehensive wastewater management strategy not only entails selecting an appropriate treatment solution, but also involves finding suitable disposal pathways for the final effluent.
In fact, treatment processes are too often decided upon without first fully understanding disposal pathway options, and determining the water quality specifications that are required from the treatment infrastructure.
Several effluent disposal pathways can be considered in most water projects:
- Long-term beneficial reuse (preferred for reduction of external environmental impact).
- Disposal to land.
- Discharge to surface waters (least favourable environmentally but often unavoidable).
- Trade waste discharge (typically high cost fees).
The Water and Carbon Group has the right expertise to assess disposal options for our clients. We can develop fit for purpose treatment solutions that meet all necessary quality requirements, without investing in superfluous infrastructure.
Long-Term Beneficial Reuse
Ability to reuse effluent for different applications, such as watering gardens and parks, is largely influenced by the choice of final disinfection. Effluent from a low energy trickling filter or wetland solution can therefore be easily transformed into a class A+ sewage treatment plant with a suitable final disinfection such as sand filter, chlorination or UV, added at the end of the process train.
Using a trickling filter or wetland solution with an added ‘disinfection’ module benefits from the ability to achieve organic and nutrient outcomes at a substantially lower power and operational cost than an mechanical solution such as and MBR. At the same time, it provides the flexibility to treat some or all of the effluent stream to a quality that meets reuse requirements, for example log 6 reduction in virus.
Disposal to Land
Our team includes agronomy and horticultural experts who are capable of assessing, designing and delivering sustainable land disposal solutions. Aspects involved in assessment can include:
- Water balance characterization;
- Agronomic modelling to determine fate of water, nitrogen, phosphorus and salts (e.g. MEDLI);
- Wet weather management strategies;
- On-site soil characterisation for effluent application;
- Habitat and ecosystem assessment of regional constraints that may affect effluent disposal solutions;
- Plant selection of suitable species for treated water characteristics;
- Irrigation design and installation;
- Development of multi-value opportunities for irrigation schemes: using effluent to rehabilitate and restore natural ecosystems and provide safe community access areas;
- Regulatory support, and;
- Integration of chosen disposal solution with treatment design.
Integrated Disposal Schemes
Where opportunities exist, The Water and Carbon Group’s engineers and ecologists can work closely with national landscape architects, to develop visionary multi-value effluent disposal solutions. The Water and Carbon Group developed the vision, concept and detailed construction design for an integrated disposal strategy for Unity Water’s Maleny Wastewater treatment plant.