Sinclair Knight Merz was a member of a consortium headed by Kilpatrick Green Pty Ltd to design and construct (D&C) a new regional sewage treatment plant (STP) at Cooma, near the NSW Snowy Mountains.
A new advanced nutrient removal facility was mandated to meet new NSW EPA sensitive waters criteria of BOD5 10 mg/L, NFR 10 mg/L, NHx-N of 2 mg/L, Tot-N of 10 mg/L and Tot-P of 0.5 mg/L (90%iles). The biosolid was also to meet NSW EPA stabilisation Grade B requirements for agricultural re-use. Given the comparatively small size (15 000 EP) and the cold winter temperatures, an IDAL type tertiary treatment facility with multi-point chemical addition was selected by Sinclair Knight Merz as the most appropriate technology for a cost competitive facility. This was confirmed through the success of the bid and the performance of the resulting facility.
The facility comprises:
- pre-treatment facilities including fine screening and grit removal
- high denitrification intermittently decanted and aerated lagoons (IDALs)
- ferrous chloride dosing for phosphorus precipitation
- dual media filtration including contact filtration using alum followed by UV
- a SCADA based control system for completely automated operation.
The involvement of Sinclair Knight Merz in the successful D&C bid and a successful commissioning demonstrates our skills in the following areas:
- low cost, competitive designs using process modelling techniques
- tight timeframe design techniques suitable for D&C tendering
- optimal process selection for unique circumstances
- greenfield process commissioning.