Plant capacity and performance:
| • 12,900 tonnes DS/year |
• 1,000 kW electricity |
| • 13,500 m³/day biogas |
• 43 % DS reduction |
| • Final product: 30% DS |
• >50% VS destruction |
The first Cambi Thermal Hydrolysis plant in Australia is installed at Oxley Creek Sewage
Treatment Plant (STP), Brisbane, as part of the Brisbane Water Environmental Alliance (BWEA)´s
sludge treatment center.
The Cambi process treats up to 95,000 tonnes of dewatered waste activated sludge (WAS) from the
Oxley Creek STP and trucked in from outling STPs.The sludge is initially dewatered to 13.5% dry
solids, then pumped sequentially into the pulper/preheater tank, where it is heated with steam
recycled from the process. It is then pumped intothe high-pressure reactors, where hydrolysis at
high temperature (155˚C) and pressure (4.5 bar)occurs. Retention time in the reactors is 20-30
minutes, after which the pressure is reduced to 2-3 bar, and the sludge flashed by pressure
differential into the "flashtank".
The surplus steam is recycled to the preheater tank.The sludge is then pumped through a heat
exchanger, into the digesters, at 8% dry solids.The Cambi process causes hydrolysis of the
microbial cells and the sludge particles through a combination of temperature and sudden pressure
reduction. Process gases are trapped, and injected into the anaerobic digester feed, eliminating any
odours.
The Cambi process has complete duty and standby on all rotating equiment. Construction
commenced in December 2005, and the plant was mechanically completed in March 2006.BWEA tested a number of disintegration and hydrolysis technologies. Cambi was the only
one that could guarantee significant biogas production and good dewatering.• Grade A biosolids
The benefits of the Cambi process are:
• >50% VS destruction
• 43% dry solids reduction in the digesters
• 30% dry solids in the final cake product
• 1000 kW electricity (installed)
• Increased loading rate of digester at ~ 8% DS
• Increased digester capacity for imported sludge
• Positive energy balance, i.e. only 25% of the biogas is used directly to operate the system.
The remaining 75% is used to generate green electricity and process steam
• 5 tonnes of WAS at ~13.5% dry solids reduced to 1 tonne of digested biosolids at ~30% dry solids
Article in Wordl Water Magazine "Australia selects Cambi THP"
Where to find the plant:
Oxley Creek Sewage Treatment Plant
Donaldson Road
Rocklea Queensland 4106
Australia
