Cosmo ball is made from plastic and the actual model is depicted as in Fig.
1. It has a proprietary design developed by UPM Waste Technology Centre
The Cosmo ball mainly has its application as a filter media in an effluent treatment
system. A very large surface area could be obtained for microbial attachment
as the Cosmo ball has a design such that a surface for fluid interaction with
the microbial is greatest.
This will greatly improve the degradation of organic matter in wastewater
trough the microbial activities.
To be specific, the application of the Cosmo ball is in regards to the trickling
process in wastewater treatment. The ball acting as the packing media will be
located inside the tank where the wastewater flows across it. This will induce
the microbial film growth and cling on the surface of the media (Lee
and Shun, 1999). The microbial will oxidize the organic matter in the wastewater.
By having a large population of microbial in the wastewater will directly translating
to a better efficiency of the treatment plant (Ahmed et
al., 2007). The specification of the Cosmo ball is shown as in Table
According to experimental analysis, the bacterial developed on the Cosmo ball
surfaces will be in excess of 5,000 to 10,000 mg L-1 (http://www.pakar.com.my/).
This high value of bacteria growth on each of the Cosmo ball will yield a good
efficiency in wastewater treatment and it is suitable in the anaerobic and aerobic
conditions. The simulation of flow across the Cosmo ball will give full insights
on the flow pattern around the ball.
|| Model of a Cosmo ball
MATERIALS AND METHODS
In modeling, the Cosmo ball was created with Design Modeler (DM) by ANSYS. The Cosmo ball model was developed as shown in the Fig. 2.
The fins around the ball serve to induce mixing in the bulk Cosmo balls wastewater system. The fluid flow is expected to divert outwards to the neighboring Cosmo ball. The flow strategy was implemented in 2 angles of attack. The direction of attack of the fluid on the ball was illustrated as Fig. 3. The 2 angles of fluid attack of 0° and 90° were analyzed. The dash line in the figure illustrates the symmetry axis of the ball.
The model of the Cosmo ball is then being brought into ANSYS Meshing
to convert it to finite element model in order for it to be solved numerically.
The physics and boundary condition is then applies. The wastewater inlet flow
velocity of 2 cm sec-1 and its direction is defined. The surrounding
is defined as an opening for the water to flow freely sideways. It is to be
noted that this simulation will not cover all the possible direction of wastewater
flow across the Cosmo ball. Instead, two extremes flow direction will only be
considered which is depicted in Fig. 3. With the two flow
direction extremes, the flow pattern could be forecasted for any possible angle
as the ball is symmetry vertically and horizontally.
|| Angle of fluid attack
|| Fluid flow velocity component scale
RESULTS AND DISCUSSION
Fluid flow system from a higher velocity to a lower velocity is shown in the scale as in Fig. 4 where it is represented by red color contour to blue color contour.
An overall exterior and interior fluid flow across the Cosmo ball was depicted
in Fig. 5a and b, respectively. It is seen
that the velocity distributed uniform namely intermediate flow region across
the Cosmo ball whereas the velocity is higher at the edge namely turbulence
flow region of the fluid flow direction. Figure 5b shows the
interior observation where the fluid flows slowly in the hollow region causing
a lag of flow for the internal zone of the ball. The fins across the Cosmo ball
caused dispersion to the fluids streamline. The overall contour plot of uniform
vector streamlines at 0° flow angle was depicted in Fig. 5c.
The angle of flow at 90° was shown in Fig. 6a and b.
It is observed that the water is still able to enter the hollow region. There
is an extremely chaotic region observed inside the Cosmo ball. The blue regions
indicate that the flow was retarded due to collision of the fluid to the wall.
||Fluid flow across at 0° (a) exterior, (b) interior and
(c) vector direction at fixed Cosmo ball position (side view) 0°
In order to show the fluid direction across the Cosmo ball, vector plot was
shown in Fig. 6c. It was observed that most of the wastewater
traps in the hollow region of the Cosmo ball.
||Fluid flow across at 90° (a) exterior (iso-view), (b)
interior (iso-view) and (c) vector direction (top view) at fixed Cosmo ball
This phenomena retards the wastewater flow, thus prolong the interaction time
between the bacteria and the wastewater.
The objective of this simulation is to analyze the flow pattern of wastewater across the Cosmo ball in the wastewater tank. It is found that the lag of flow in the individual Cosmo ball indicates that the hollow region in the ball can induce higher retention time for wastewater treatment. This will greatly improve the efficiency of the wastewater treatment plant as well as to reduce the area needed for the treatment due to sufficient time for the microbial in the wastewater to obtain oxygen for oxidation process.
First and foremost, I would like to express my deepest gratitude, appreciation and support to the staffs of Pakar Management Technology their valuable information, advice and comments trough the achievement of this project.