Due to the increase of nitrogen loading in wastewater from the city of Tallinn, Tallinn Water decided to invest in a new tertiary treatment step at Paljassaare WWTP (PE 400,000). In the first stage, the post treatment can handle 60 % of the total flow. Existing nitrogen removal process consists of denitrification and nitrification within aeration basins followed by secondary clarifiers. To achieve reduction in total nitrogen, methanol is fed into the process.
The new enhancement (currently under construction) step consists of Veolia’s Biostyr filters which are located inside a new filter building. Water from the plant outlet is pumped from existing outlet pipes to filters and returned to the same outlet pipes after filtration steps. Additionally new methanol pumps and pipes are designed in connection to the assignment. With the new process in operation, Paljassaare WWTP can reach effluent concentrations for total nitrogen of < 10 mg/l.
|Name of client||Tallinn Water|
|Origin of funding||Tallinn Water|
|Name of partners||Teim Elekter OÜ|