Casino STP
Richmond Valley Shire Council: Casino Constructed Wetland
The Casino STP was built in the 1930s as a trickling filter plant with a 4ha tertiary pond. A constructed wetland of 5ha was added in 1990. The wetland was originally designed to operate at a constant depth of 200mm, regulated by weirs of gravel, but in 2000 was in fact a series of shallow ponds resulting in compliance violations, mainly for Suspended Solids.
Challenges
- Retrofit existing constructed wetland with improved water levels, wetland plant populations and flow structures
- Improve treatment performance
- Phosphorus accumulation in the constructed wetland
Our role
- Re-design of constructed wetlands
- Supervision of construction
- Training STP operators in wetland operation and management
Outcomes
- High quality low cost sewage treatment
- Fully-vegetated constructed wetland with litter layer development
- Water level and flow management improved to achieve high quality treatment
Our Solution
The pond and wetland system was re-designed in stages in parallel with the South Lismore and West Byron systems, and managed in partnership with Council engineering staff and STP operators. Wetland floors were re-graded and planted, along with installation of new inlet and outlet arrangements.
Consistent good performance at relatively low cost has been experienced, with good compliance with EPA licence conditions. Council is currently planning significant expansion of the wetlands.
A comprehensive 3 year research program is underway in the wetlands to detail nutrient reduction processes, under a partnership between Southern Cross University, WCG and three Shire Councils. This work is expected to lead the way in confirming and enhancing the design approach.
