DSP (Dynamic Simulator for Prefermenters) is an advanced PC productivity tool for analyzing the design, operation and optimization of prefermenters in biological nutrient removal (BNR) wastewater treatment plants.
Prefermentation is an increasingly popular unit operation in BNR wastewater treatment plants, used to promote rapid denitrification and biological phosphorus removal in these processes. Its aim is to produce volatile fatty acids (VFAs) which can assist in the BNR process. The bacteria responsible for biological nutrient removal in the wastewater treatment process require soluble organic products such as VFAs for use as an energy and carbon source.
Featuring latest modeling technology, DSP allows engineers and plant operators to study optimization of existing prefermenter installations, evaluate operational sensitivities and assess the benefits of adding prefermentation facilities to existing wastewater treatment plants.
DSP is also the first commercially available prefermenter simulator - providing wastewater practitioners for the first time with an analytical tool for the design and operation of prefermenters. To date, prefermenter design and operation has been largely restricted to empirical rules and guidelines - often specific to proprietary designs.
The mathematical model incorporated in the DSP software has been validated on a number of full-scale plants with commonly used prefermenter configurations. These include static prefermenters, activated primary tank (APT), complete-mix and two-stage prefermenters.
Operation is as simple as specifying the wastewater influent characteristics (VFA, SCOD, TCOD, TKN and NH4). DSP can then be used to predict prefermenter effluent characteristics and mass of VFAs produced over a range of prefermenter hydraulic and solids residence times (HRT/SRT), reactor size and flow conditions - for use by subsequent BNR processes.
Using DSP, you can:
Perform steady-state simulations and assess sensitivities of the
process to changes in influent concentrations, flows, reactor volume and
Perform dynamic simulations to assess the dynamic behaviour of
the process to programmable changes in operating conditions.
Simulate batch prefermenters for pilot plant and research
Simulate prefermenter start-up behaviour.
Predict the pH value in the prefermenter for use as a surrogate
VFA control and monitoring parameter.
DSP provides operators and engineers for the first time with an
analytical tool for cross-checking and evaluating prefermenter configurations
to augment or optimize existing BNR plants. By estimating mass of VFAs
produced under local operating conditions and wastewater composition, DSP
facilitates an independent assessment of the cost benefits of adding a
prefermenter to a plant or optimizing conditions for an existing
The mathematical model incorporated in the DSP software has been
validated comprehensively on a number of full-scale plants with commonly used
prefermenter configurations. These include static prefermenters, activated
primary tank (APT), complete-mix and two-stage prefermenters. The model was
tested under temperate and sub-tropical conditions, thus covering a
potentially large range of wastewater types and climatic conditions.
DSP focuses specifically on prefermenter simulation, rather than
modeling the prefermenter as part of a BNR plant simulator. This has the
advantage that prefermentation systems can be analysed in detail without the
need for BNR plant simulation software. DSP steady-state, dynamic and batch
simulations can also be applied to existing BNR plant simulators by using
predicted outputs from DSP (or suitable data conversions) as inputs into the
Using DSP steady-state simulation
mode, model outputs can be plotted versus any operating variable to
visualise the effect of that variable on model outputs. For example, the
effluent VFA concentration can be plotted versus HRT, SRT or influent
components to determine optimal values. Standard steady-state plots vs time
are also available in this mode.
The DSP dynamic simulation mode
provides the flexibility to simulate effects of both sudden and gradual
changes in operating conditions, by single or multiple parameters. Input
profiles are user programmable, and can be used to simulate changes in HRT,
SRT and influent characteristics. The dynamic mode shows the dynamics of the
system and how long it may take to reach new steady state conditions. Another
useful application of this mode is the simulation of prefermenter start-up
For research applications, the DSP batch
simulation mode can be used to simulate the performance of a batch
prefermenter. The user simply specifies the initial reactor wastewater
composition since these systems operate under zero flow conditions.
DSP optionally provides facilities to predict prefermenter pH as
a surrogate parameter for VFA monitoring and control - catering for cases
where VFA measurement data is not readily available. The built-in pH
Calibration Wizard can supply defaults based on wastewater composition,
or compute an optimal fit using non-linear optimization for users who wish to
add their own calibration data (VFA concentrations and pH values).
The built-in DSP setup wizards enable users to quickly set up
model parameters for a particular prefermenter simulation. Using the
QuickStart Wizard, the user simply types in the influent
characteristics and required operational parameters for the prefermenter.
Where analytical data is available from an operating prefermenter, the
Tuning Wizard can be used to tune model parameters to the
characteristics of that prefermenter.
The DSP design emphasis is on ease of use, productivity and
simplicity for routine PC users - without need for the extensive training or
mathematical knowledge often required by users of modeling software. Included
also, are automatic unit conversions, instant hint bar, glossary, context
sensitive help facilities and a user logbook for simulation
The DSP package includes a
comprehensive Prefermenter Technology Book reviewing latest
developments and methodologies for wastewater prefermentation systems, as well
as detailing prefermenter modeling and DSP
Depending on capacity requirements and wastewater composition, there can be major capital costs associated with the design and installation of prefermenter systems. The availability of low-cost simulation software now provides an invaluable tool to assess prefermenter designs and the possible benefits of adding a prefermenter to a BNR plant.
For consultants, plant operators, researchers and academic institutes, DSP also provides a means to gain useful and up-to-date industry knowledge on prefermenter technology.
For day-to-day plant operations, wastewater plants are coming
under increasing legislative and environmental requirements to control
phosphorus and nitrogen levels in plant effluent - prefermentation can play a
key role in reducing these levels.