BIO-FIT wastewater treatment plant is designed according with ATV A135 specifications and consists of the following elements:
- preliminary settling tank,
- submerged fixed-bed biofilm reactor,
- clarifying chamber,
- installation chamber.
Fig. 1. The design of BIO-FIT wastewater treatment plant
Chambers located underground are the core of the wastewater treatment plant. This limits odour emission. The chambers are made of C 35/45 class concrete but can be also made of other materials (e.g. polymer concrete).
- Short development time due to using Ecol-Unicon precast elements.
- Easy modular construction - easily adapted to the terrain conditions.
- Easy operation and maintenance.
- Energy efficiency (gravitational flow - lack of pumps pumping the wastewater).
- Low operation costs (the number of mechanical devices is limited to minimum).
- Resistant to flow changes.
- Monitored by BUMERANG system (one system for all facilities), which provides complete information about the work of installed devices and helps to optimise maintenance costs.
The treatment process in BIO-FIT wastewater treatment plants consists of two phases: mechanical treatment and biological treatment. Mechanical treatment takes place in the preliminary settling tank. It uses the processes of sedimentation and suspended solids flotation. The settling tanks are designed in such way to equalise uneven inflow of wastewater. Biological treatment takes place in the reactor's chamber with fixed-bed biofilm. The air is pumped into the reactor by air supply units. In the course of the biological process surplus waste is created that is later retained in the clarifying chamber and then returned to the preliminary settling tank. The treated wastewater that flows out of the clarifying chamber does not require further pre-treatment and can be directed into the receiver.
The plant uses gravitation for wastewater flow, which reduces energy consumption.
Operation of already existing wastewater treatment plants with submerged fixed-bed biofilm shows that the average amounts of BOD5, COD and suspended solids at the outflow are much below the standards stipulated by Polish provisions of law.