Bydgoszcz, PL

Plant capacity and performance:

The first Cambi Thermal Hydrolysis plant (THP) in Poland is located at the Kapusciska wastewater 
treatment plant in Bydgoszcz. The plant was having problems with digestion as the mixed sludge
has a high content of long sludge age secondary sludge that is both difficult to digest and dewater.
Cambi’s supply included pre-dewatering, silo, co-generation plant for electricity and steam,buildings 
and all necessary civil works. The Cambi THP process treats up to 7,650 tons of dry solids per year. 
The sludge is initially dewatered to 16% dry solids, then pumped sequentially into the pulper/preheater 
tank, where it is heated with steam recycled from the process. It is then pumped into the high-pressure 
reactors,where hydrolysis at high temperature (165°C) and pressure (6 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 "flash tank". The surplus steam is recycled 
to the pulper. The sludge is then pumped through aheat exchanger, into the digesters, at 10% 
drysolids.

The Cambi process causes hydrolysis of themicrobial 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 equipment.

Cambi AS commissioned the plant in August2005 and transferred operations to plant managers 
in March 2006.  

The benefits of the Cambi process are: 

• 57% VS destruction
• >48% dry solids reduction
• 31-33% cake solids in the final product
• 1100 kW electricity (installed)
• Very high digester loading rate (10%DS), rapid conversion with no foaming,and 2-3 times
  increased digester yield
• Very energy efficient heat treatment due to recycling of process steam and high DS treatment 
  (16-17% DS)
• Positive energy balance, i.e. only 20% of the biogas is used directly to operate the system.
  The remaining 80% is used to generate green electricity and process steam
• Cake production decreased to less than half, from 19,600 tons in 2004 to 9,500 tons in 2006
• Grade A/pathogen-free biosolids with no odour and no re-activation/re-growth  

Article in World Water Magazine