Water intake Drweca
The “Drwęca” water intake, together with the water treatment plant, is located in Lubicz in immediate vicinity of the Drwęca River. It comprises a bay water intake with first grade pumping station and transformer station. The level difference between pumping station first grade and the water treatment plant exceeds 40 m. Due to the fact that water is taken directly from the river; the intake is very sensitive to potential negative fluctuations in the quality of surface water.
The designed capacity of the Drwęca water intake is 2750 m3/h.
The designed capacity of the water treatment plant "Drwęca-Jedwabno" is 3500 m3/h.
The water treatment plant "Drwęca-Jedwabno" is fed with water by the “Jedwabno” groundwater intake and “Drwęca” surface water intake.
Crude water flows through the bay into an intake chamber linking the bay to a pumping station (1st grade). In the intake chamber crude water is cleaned from mechanical impurities and small organic suspension on rotary sieves.
Primary purified water is pumped into two water pipes leading to the Water Treatment Plant (WTR) where crude water is treated.
A separate water main leads from the infiltrating intake “Jedwabno” to the WTR. Crude water from this water intake can be treated on selected treatment stages or the entire production line – depending on its quality.
Water pipe outlets lead to primary oxidation chambers where the water oxidation process proceeds. This stage of water treatment is called 1st grade bacteriological treatment, because here organic parts are oxygenated through the contact of water with ozone. The 2nd stage of water treatment is carried on in a “coagulation” building. This stage of water treatment consists of a series of physical and chemical processes (coagulation, flocculation) using chemical substances which cause the precipitation of suspended matter from the water. Precipitated suspensions are separated from the water in settlers. Next, the water is filtrated through sand and anthracite filters what improve the water taste and odour. After filtration, the next water treatment stage involves intermediate ozone oxidation. This causes further oxidation of iron and manganese, because the most substances have already been removed and their impact is reduced to minimum. The efficiency of the process can be improved by adjusting the water pH.
After intermediate ozone oxidation the water is pumped to a second stage filtration which is conducted on an activated carbon bed. Colloidal substances which effect the turbidity, taste and odour of water are removed here. Due to a large content of organic matter in raw water this process is indispensable, since it also leads to the removal of previously oxidised iron and manganese compounds.
The final process of water treatment is disinfection using chlorine dioxide generated in a chlorinator building. Purified water is collected in three equalizing tanks to ensure continuous supplies of water to the city. Treated water is pumped from these tanks through the 2nd grade pumping station to a water supplying the municipal water supply system.
Other WTP's objectives:
– Objects of the deposit management - are used to clean water used to rinse the filters and coagulation facilities.
– Ozone building (ozonisation station) – here ozone is generated to use in the process of treating water.
– Hall of blowers – here are sited air blowers which generate compressed air for the periodic rinsing of filter chambers.