Numerical modelling and simulation of pollutant transport in Neretva

Abstract

Waste water, discharged into the river system is in processes of transport and mixing. After fully cross mixing, the pollution transport is one-dimensional. The aim of the study was to model the discharge, salinity and biochemical oxygen demand and dissolved oxygen (BOD and DO) loads along the Neretva River, on the section of Mostar to Žitomislić. MIKE-11 a one dimensional hydrodynamic simulation program was utilized to model stream flow transport and water quality processing in the river system. Hydrodynamic Modele (HD) was applied to calculate water level an flow for the river. Advection-Dispersion and Water Quality Modele (AD/WQ) was used to transport and spreading of salinity and BOD and DO concentrations. Model is calibrated on the basis of available experimental data. Data of another time series are used for verification of last mentioned. The comparative analysis between measured and simulated data showed that MIKE-11 is able to predict sufficiently accurate BOD and DO loads and salinity at the catchment outlet.

Otpadne vode, ispuštene u vodotok, podliježu procesima transporta i miješanja. Nakon potpunog poprečnog miješanja, problem je dalje moguće razmatrati jednodimenzionalno. Cilj istraživanja ovog rada bio je modelirati proticaj, salinitet i opterećenja biohemijske potrošnje kisika i otopljenog kisika (BPK5 i O2) duž rijeke Neretve na potezu od Mostara do Žitomislića. MIKE 11 - hidrodinamički simulacijski program je korišten kao model toka i transporta, te procesa kvaliteta vode u vodotoku. Hidrodinamički model (HD) korišten je za proračun nivoa vode i proticaja u rijeci, a advektivno - disperzni model (AD) i model kvaliteta vode (WQ) korišteni su za modeliranje saliniteta te pronosa i širenja BPK5 i O2 koncentracije. Kalibracija modela obavljena je na osnovu raspoloživih eksperimentalnih podataka, a za verifikaciju su korišteni podaci dobijeni statističkom obradom druge mjerene vremenske serije. Uporedna analiza između mjerenih i simuliranih podataka pokazala je da je model MIKE 11, samo ako je dobro kalibrisan, u stanju predvidjeti dovoljno tačna opterećenja BPK5 i O2 te saliniteta na razmatranom slivnom području.