UASBR: An Effective Wastewater Treatment Option to Curb Greenhouse Gas Emissions - Management of Natural Resources in a Changing Environment - page 124

Table 1 Wastewater characteristics
Sr. No. Parameters Unit Inlet

1 pH - 7.0-9.0

2 Total dissolved solids mg/L 15,000-25,000

3 Total suspended solids mg/L 100-200

4 Volatile suspended solids mg/L 50-150

5 COD mg/L 7,000-8,000

6 BOD mg/L 2,500-3,500

7 Oil and grease mg/L <30

MLSS (mg/L) MLVSS (mg/L)

100000

80000

60000

40000

20000

0

1 11 21 31 41 51 61 71

Days

Fig. 3 MLSS and MLVSS trend

UASBR Performance

Acclimatization of micro organisms for the wastewater was judged from the analy-
sis of MLSS and MLVSS in the reactor. MLVSS represents the micro organisms in
the reactor, responsible for biodegradation of organics. The organic loading rate
(OLR) was increased or decreased based on the MLVSS in the reactor. During start
up phase, ups and downs were observed in the MLVSS value. If sharp reduction of
25 % in MLVSS value was observed during acclimatization period, part of waste-
water feed was replaced with jaggery solution in order to maintain 0.5 food/micro-
organism (f/m) ratio. The process stabilized in 60 days and after that continuous
increase in MLVSS was observed (Fig. 2 ).
OLRwasalwaysmaintainedabove1kgCOD/m 3 /day by combination of organ-
ics supplied from process effluent and jaggery. Initial OLR from effluent was kept
as low as 0.5 kg/m 3 /day and increased in a stepped manner to 4.5 kg/m 3 /day over a
period of 75 days (Fig. 3 ). The process was found stabilized at this point and the
systemwasoperatedforalmost1monthwiththisOLR.Consistencyinthetreated
effluent was observed during this period.