Modeling of the process of biological treatment of wastewater of the town of Beli Manastir

Obrada otpadne vode s aktivnim muljem izrazito je složen proces, a nestalnost sastava i protoka otpadne vode te vremenski promjenjive reakcije mikroorganizama uvjetuju njegovu nelinearnost i dinamičnost. S tim u skladu i njegovo je optimalno vođenje otežano, i odgovarajući matematički model mogao bi biti odgovor na ovaj izazov. U ovom radu analiziran je proces biološke obrade komunalne otpadne vode grada Belog Manastira u određenom razdoblju. Mjerenja različitih parametara provode se svakodnevno s ciljem uvida u učinkovitost procesa obrade na navedenom uređaju. Na temelju baze podataka, izrađeni su viševarijantni linearni modeli (MLR) i lokalni linearni modeli (PLR) s različitim brojevima varijabli u svrhu predviđanja izlaznih vrijednosti kemijske potrošnje kisika (KPK) i biološke potrošnje kisika (BPK5) kao glavnih pokazatelja organskog opterećenja komunalnih otpadnih voda. Modeli su ocijenjeni i uspoređeni na temelju vrijednosti pripadajućih regresijskih koeficijenata čija je vrijednost za sve izrađene modele prelazila 0,89, što ukazuje na zadovoljavajuću točnost.Wastewater treatment with activated sludge is a very complex process, and nonstationary behavior of pollutant concentration and time variation of microbial activity results in nonlinearity and dynamic character of the process. Based on these characteristics optimal process control is difficult, and an appropriate mathematical model could be the solution to this challenge. This paper analyzes the process of biological treatment of municipal wastewater in the town of Beli Manastir in a certain period. Measurements of various parameters are performed daily in order to gain insight into the efficiency of the process in this specific plant. Based on the database, multivariate linear regression (MLR) and piecewise linear regression (PLR) models with different numbers of variables were developed with the aim of predicting the output values of chemical oxygen demand (COD) and biological oxygen demand (BOD5) as the main indicators of municipal wastewater organic load. The models were evaluated and compared based on the values of the corresponding regression coefficients whose value for all developed models exceeded 0,89, which indicates satisfactory accuracy