2. AN ALGAL BIOMASS PREDICTION MODEL
Introduction
Nutrient Cycling
The Nitrogen Cycle
Phosphorus Cycle
Silica Cycle
Summary of Nutrient Cycles
Simulation Method
Introduction
Numerical Accuracy
Traditional Approach
Backtracking Approach
Model Uncertainty
3. AN ALGAL BIOMASS PREDICTION MODEL
Introduction
Nutrient Cycling
The Nitrogen Cycle
Phosphorus Cycle
Silica Cycle
Summary of Nutrient Cycles
Simulation Method
Introduction
Numerical Accuracy
Traditional Approach
Backtracking Approach
Model Uncertainty
4. Simulation model: DELWAQ-BLOOM
This model is used to predict algae growth
and mortality, oxygen concentrations and
nutrient dynamics
This model process can be grouped into:
nutrient cycling, algae modeling, and oxygen-
related process.
5. The DELWAQ-BLOOM model
assumes that algae consumes
ammonia and nitrate in the
water column.
Optionally the model
includes algae species with
the ability to take up atomic
nitrogen and detritus.
6. Two important
The nitrogen cycle
reaction in the
consider the water-
nitrogen nutrient
column components
cycle
• e.g. ammonia, nitrite and • Nitrification and
nitrate, algae, suspended denitrification
detritus and suspended
(non-dertitus) organic • nitrification (production
nitrogen. of nitrate in system) and
denitrification (nitrate
is removed from the
system).
• These reaction affect the
flux of ammonia and
nitrate in the water
column.
7. A simplified The specified
version of the reaction of
nitrogen cycle this cycle is
the
absorption /
desorption of
particulate
inorganic
phosphorus
8. A simplified The specified
version of the reaction of
nitrogen cycle this cycle is
there is no
absorption of
silica to
inorganic
suspended
solids.
9. The nutrient cycle just described are
based on the assumption that nutrients
can be recycled an infinite number of
times without any loses other than due
to transport, chemical absorption,
denitrification and burial.
10. AN ALGAL BIOMASS PREDICTION MODEL
Introduction
Nutrient Cycling
The Nitrogen Cycle
Phosphorus Cycle
Silica Cycle
Summary of Nutrient Cycles
SIMULATION METHOD
Introduction
Numerical Accuracy
Traditional Approach
Backtracking Approach
Model Uncertainty
11. Numerical
Accuracy
Simulation
Backtracking
Method –
Approach water
quality Traditional
models Approach
12. Water quality simulation
models based on
physical, biological and
chemical processes typically
include time rate of change
terms as dC/dt.
13. Most water quality Time is divided into discrete
simulation models simulate intervals and the flows are
quality over a consecutive assumed constant within
series of discrete time each of those time period
periods. intervals.
At the end of each
Each water body is divided period, mixing occurs within
into segments or volume each segment or volume
elements, and these are element to obtain the
considered to be in steady concentrations in the
state conditions within each segment or volume element
simulation time period. at the beginning of the next
time step.
14. Backtracking approach eliminates the need to
consider the simulation time-step duration
restriction. The backtracking approach permits
any simulation time-step duration to be used
along with any segmenting scheme.
Unlike the traditional approach, water can
travel through any number of successive
segments or volume elements in each
simulation time step.
Instead of following the water in a segment or
volume element downstream, the system tracks
back upstream to find the source concentration
of the contaminants.
