Introduction. Among characteristic features of waste paper recycling plant wastewater, the following can be distinguished: significant fluctuations in consumption and composition, high content of undissolved and dissolved substances (in particular, starch, fiber, dispersed thermoplastic and other substances). Local wastewater treatment can reduce the concentration of undissolved and — partially — dissolved contaminants. Besides, it makes it possible to reuse valuable substances and treated water in production. However, a significant amount of dissolved contaminants is dumped by factories at off-site biological treatment plants. In this case, bioreactors with suspended activated sludge (aeration tanks) as well as bioreactors with attached biomass are used for wastewater treatment. Methods. The purpose of the study was to determine the consumption and composition of wastewater discharged by waste paper recycling plants, as well as the technological parameters and performance of biological treatment facilities, including a moving bed biofilm reactor and aeration tanks. In-process control over the operation of treatment plants was carried out by means of instrumental measurements and laboratory analyses conducted according to standard methods. Results. The article examines the results of the operation of biological wastewater treatment facilities used to treat wastewater from a paper mill, where different grades of waste paper are used as raw materials. The main characteristics of biological wastewater treatment facilities’ operation have been identified. Relationships between the oxidation capacity and the load in terms of organic pollution have been obtained for a bioreactor with a moving bed (1st stage) and aeration tanks (2nd stage of biological wastewater treatment). Measures have been proposed to improve the performance of existing treatment plants.
Operational characteristics of the paper factory's biological wastewater treatment facilities
