- ASpect’s Client: Beca Hunter H2O
- Head Client: Shoalhaven City Council
- Plant Configuration: IDEA
- Plant Size: 28,000 EP, 10,500 EP, 16,000 EP and 8,000 EP
- Project Value: $250k (ASpect Fee $95k)
- Project Duration: October 2023 to August 2024
Southern Shoalhaven STP Options, with Beca Hunter H2O for Shoalhaven City Council (NSW).
Sholahaven City Council (SCC) own and operate a number of STPs in the Shoalhaven region of NSW. This region is a popular, coastal holiday destination with high growth. During holidays, especially those in summer, the population and sewage load increases suddenly and dramatically. This places unique stresses on the STPs and their operation. ASpect had previously assisted with a process review of four of their STPs in the southern Shoalhaven, namely Ulladulla STP, Culburra Beach STP, St Georges Basin STP and Sussex Inlet STP. The process review identified capacity and pefformance shortfalls in all of the four STPs. This triggered an amplification and upgrade programme, starting with an options assessment of all four STPs. The options shortlisted varied for each STP based on the existing facilities, loadings, constraints and lessons learned as each options assessment was conducted. Secondary treatment options covered sequencing batch reactors (SBRs), membrane biological reactors (MBRs) as well continuous flow activated sludge in MLE and FSB configurations. Biosolids stabilisation options included sludge lagoons, aerobic digestion and anaerobic digestion coupled with themal hydrolysis. Wet weather options included storm cycles, solids contact treatment plus storage and return. Other sub-options included bioreactor aeration (mechanical, fine bubble diffused and mechanical diffused), dewatering (mobile centrifuge and permanent screw press) and options to deliver the desired process using different existing facilities. Recycled water treatment options were also considered. The preferred option for each STP was found to be conversion to continuous flow biorectors with aerobic digestion for sludge stabilisation and permanent screw press dewatering. The means of delivering these processes was different for each STP, making full use of the existing civil assets. Wet weather treatment was customised to meet the unique discharge and recycled water constraints of each STP. SCC were also provided with options to defer some or all components of each upgrade based on prioritisation.
