The MBR Book: Principles and Applications of Membrane

Table 3.34 Aeration design
Parameter Value Unit
Tank depth 3 m
P a,2 131 kPa
OTE membrane 0.06 %
OTE biological 0.14 %
Q� A,m 1.61 Nm 3 /s
O 2 transferred by membrane aeration 24.87 kg/day
O 2 required to maintain biology 1409 kg/day
Q� A,b 1.38 Nm 3 /s
Table 3.35 Power requirements
Air blower Value Unit Liquid pump Value Unit
parameter parameter
� blower 0.50 � pump 0.45
Power 80.70 kW Power 3.44 kW
(biological) (permeate)
W b 0.40 kWh/m 3 W h 0.02 kWh/m 3
Power 94.27 kW Power 9.11 kW
(membrane) (recycle)
W b,V 0.46 kWh/m 3 W p 0.04 kWh/m 3
Table 3.36 Costs
Costs Value
Power cost/kWh $0.10
Total energy/unit permeate 0.922 kWh/m 3
Total energy cost/Unit permeate $0.09
Chemical cost/kg $0.50
Chemical Usage/Unit permeate 0.0065 kWh/m 3
Total chemical cost/unit permeate �$0.01
Total cost/unit permeate $0.10
Estimated annual OPEX $170,066
Design 157
the conditions given in Tables 3.25–3.27. According to this correlation (Fig. 3.5), the
specific cost per unit volume permeate generated decreases with flux, as would be
expected, and is around 33% lower for the HF than for the FS module.
However, a degree of caution is required in interpreting these data in that:
(a) The calculation does not account for the impact either of membrane life, which
may possibly relate to permeability (which is generally higher for the FS modules),
or sludge dry solids concentration on sludge disposal costs.
(b) There is considerable scatter in the data from which the J net:SAD m correlations
were obtained. Over the range of SAD m values applied in practice for the
same SAD m value the operating cost of the HF module is �19% lower than
that of the FS module (Fig. 3.6).