UASBR: An Effective Wastewater Treatment Option to Curb Greenhouse Gas Emissions - Management of Natural Resources in a Changing Environment - page 127

(a) Methane generation and power production

3

CODreductioninthe reactor = 3 500 , mg L mday

kg d

/ × 240 / / , 1 000

/ay
Approx methanegeneration CH kgCODreduced

= 840

3

. @ . 030

03084

/

4

3

=×0 . = 252 m ay /

3

mh
PowerproductionVol of methane

= 10 5 . /

( )

= . . ue engine eff

mh kcal m
kW

× cal val × ./ 860

3 3

= 10 5 . / × 9 500 , / × 035 860 . /

= 40 6 . h = 974 kWh day /

(b) Power consumption of 1,494 kWh/day can be achieved due to installation of
UASBR in place of aerobic reactor as provided in Table 3 . This reduction is due
to elimination of aeration tank blowers which are major power consumer in
efluenttreatmentplant.Considering330daysofmanufacturingfacilityopera-
tion, the annual saving in power consumption results to 4,93,020 kWh.

( ) = ( )

(c) Totalsavings in power consumptionab

+ 321 420 493 020

8

,, , + ,

= ,14 440 , kWhannum /

(d) Considering, 1 tonne CO 2 is released with generation of 800 kWh electricity
( www.carbonfootprint.com ), reduction in GHG emissions for 8,14,440 kWh
consumptionis1,020tonnesperannumCO 2 emissions.
(e) To offset 1,020 tonnes of CO 2 emissions, 6,50,000-10,00,000 INR should be
invested in clean energy and reforestation (Fig. 5 ).

Table 3 Power consumption comparison for aerobic reactor versus UASBR

Equipments for
aerobic reactor

Power consumption
(kWh/day)

Equipments
for UASBR

Power consumption
(kWh/day) Sr. No.

1 AT blower 1,536 UASBR feed

pump

85

2 Sec clarifier

mechanism

35 Sludge pump 20

3 Sludge

recirculation pump

28

Total 1,599 105