The existing, obsolete wastewater treatment plant could not provide an acceptable reduction of pollutants, so an EU co-financed project was started in order to design and construct a new technology, which securely fulfills all water quality requirements. The technology includes: mechanical treatment (fine screens, aerated grease and sand removal), BIOCOS type aerobe activated sludge treatment, with chemical dosing (additional phosphorous removal). The BIOCOS (BIOlogical COmbined System) technology unites the advantages of the „classical” continuous flow activated sludge processes and the SBR technologies, providing flexible operational conditions.
The excess sludge is thickened gravitationally, and it gets further dehydrated with sludge-centrifuges, up to 22% TS.
The six month long trial period was closed successfully.
The wastewater discharge regulations, and the trial period results are the following:
| discharge limit | trial period results | ||
| KOIkr | 75 | 75 > | g/m3 |
| BOI5 | 25 | 25 > | g/m3 |
| Total-N | 35 | 35 > | g/m3 |
| Total inorganic-N | 30 | 30 > | g/m3 |
| Total-P | 5 | 5 > | g/m3 |
| TSS | 35 | 10 > | g/m3 |
| NH3-NH4-N | 10 | 1 > | g/m3 |
