2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Environmental Chemistry & Technology
P10 DyNAMIC SIMuLATION OF bIOLOGICAL
NITROGEN REMOVAL PROCESSES
LEnKA ČERnOCHOVá a , Ján DERCO a and MAnFRED
SCHüTZE b
a Faculty of Chemical and Food Technology, Institute of Chemical
and Environmental Engineering, Slovak University of
Technology, Radlinského 9, 812 37 Bratislava, Slovakia,
b ifak – Institut für Automation und Kommunikation e.V. Magdeburg,
Werner-Heisenberg-Str. 1, 39106 Magdeburg, Germany,
lenka.cernochova@stuba.sk
Introduction
With rising requirements for protection water resources
and thereby for quality of effluent wastewater too, more
complex technologies for wastewater treatment are applied
as well. These technologies are characterised by more processes
with different reaction rates and requirements in term
of reaction conditions, interactions and generally by more
complex structure of treatment lines. The complexity of these
systems is also related to mutual interaction between wastewater
treatment plant (WWTP) and others parts of the urban
wastewater system, e.g. sewer system and receiving water
(Derco and Schütze, 2004). Consequently, designing of processes
and technologies and their efficient operation are also
significantly complex.
Mathematical models and simulations programs belong
to prospective and currently more often utilised tools. They
offer a simple way how to analyse changes in technologies
at WWTP by optimisation or intensification already existed
plants or it can help by designing new WWTPs as well.
The results of application of the Activated Sludge Model
no. 1 (ASM1) (Henze et al., 1987) using dynamic simulations
for verification of steady state design with regard to dynamic
behaviour of the WWTP and for prediction dynamic effluent
concentration values are presented.
Dynamic Simulation of wwTP
ASM1 was used for modelling of the biological stage
at real WWTP in nové Zámky (Fig. 1.). Two series of measurements
included diurnal variations of wastewater flow
and composition in input and output at the biological stage
were carried out. The first set of measurement was perfomed
in May 2002, when the nitrification process was operated.
Because of expected more stringent requirements in effluents,
this activated sludge plant was upgraded in 2003 applying a
pre-denitrification system. The second measurements were
realised after the reconstruction (in March 2007). The results
of measurements were transformed into organic and nitrogen
pollution fractions according to structure of the ASM1.
For comparison of the experimental and the calculated
resultant concentration values in the WWTP effluent were
chosen criteria according the Regulation of the Slovak government
(2005). The model ASM1 and the default parameter
values included in the SIMBA program have been used for
s353
performing dynamic simulations. The calculated concentration
values for individual pollutants in daily composite samples
were calculated based on pollutant mass balancess.
Fig. 1. Schemes of wwTP setups; Above: wwTP before reconstruction
(2002); below: wwTP after reconstruction (2007)
Results
M o d e l S u i t a b i l i t y
First step of simulations was to verify suitability of
ASM1 to describe WWTP. From the results (Fig. 2) it can be
concluded that the dynamic simulations describe the experimental
effluent values quite well.
V e r i f i c a t i o n o f S t e a d y S t a t e
D i s i g n b y D y n a m i c S i m u l a t i o n
The purpose was to verify the results of conventional
steady-state design of the WWTP biological stage (Derco et
al, 2004) for future upgrading with regard to expected load in
2036. The data for this scenario were obtained from the operator
of the WWTP – Západoslovenská vodárenská spoločnosť,
a.s. Resulting values (7 mg dm –3 ammonium nitrogen
and 9.3 mg dm –3 total nitrogen) of dynamic simulations are
lower than today’s effluent standards (10 mg dm –3 ammonium
nitrogen and 15 mg dm –3 total nitrogen). It can be summarised
that the steady state design for the WWTP upgrading
Fig. 2. Effluent concentrations of ammonium nitrogen at
wwTP after reconstruction ( * experimental and – calculated values)