The document discusses using an Upflow Anaerobic Sludge Blanket (UASB) reactor to treat leachate from the Okhla landfill in New Delhi. A UASB reactor uses anaerobic microorganisms to break down waste as it flows upwards through a blanket of granular sludge. A laboratory-scale UASB reactor treated leachate over 8 months at an organic loading rate of 3 kg COD/m3-day. The reactor was more effective at treating fresh leachate (91-67% COD removal) than older, more toxic leachate (90-35% removal). UASB reactors offer advantages over conventional treatment by consolidating settlement, digestion and

1. UASB REACTOR
FOR LEACHATE
TREATMENT
IN OKHLA LAND FILL
BY: GANESH KUMAR
10/FET/C(S)/2049

2. Toxicity and
treatability of
leachate: application
of UASB reactor for
leachate treatment
from Okhla landfill,
New Delhi.

3. WHAT IS UASB ?
# upflow anaerobic sludge blanket
 # Upflow anaerobic sludge blanket (UASB)
technology, normally referred to as UASB
reactor, is a form of anaerobic digester that is
used in the treatment of wastewater.
 The UASB reactor is a methanogenic
(methane-producing) digester that evolved from
the anaerobic clarigester. A similar but variant
technology to UASB is the
expanded granular sludge bed (EGSB)
digester.

5.  UASB uses an anaerobic process whilst
forming a blanket of granular sludge
which suspends in the tank. Wastewater
flows upwards through the blanket and is
processed (degraded) by the anaerobic
microorganisms. The upward flow
combined with the settling action of
gravity suspends the blanket with the aid
of flocculants.

7.  Upflow Anaerobic Sludge Blanket
(UASB)
 upflow anaerobic sludge blanket (UASB)
process to treat the leachate from a
municipal landfill located in Delhi.
 A laboratory scale reactor was operated
at an organic loading rate of 3.00 kg
chemical oxygen demand (COD)/m(3) d
corresponding to a hydraulic retention
time (HRT) of 12 h for over 8 months.

8.  The effect of toxicity of leachate, and
feed composition on the treatability of
leachate was evaluated. Average COD
of the leachate, during the study period
varied between 8,880 and 66,420 mg/l.
 Toxicity of the leachate used during a
period of 8 months varied from LC50
1.22 to 12.35 for 96 h. The removal
efficiency of soluble COD ranged
between 91 and 67% for fresh leachate
and decreased drastically from 90 to
35% for old leachate having high toxicity.

9.  The efficiency varied from 81 to 65%.
The reactor performed more efficiently
for the treatment of fresh leachate (less
toxic, LC50 11.64, 12.35, and 12.15 for
96 h) as compared with old leachate
(more toxic, LC50 1.22 for 96 h). Toxicity
of the leachate affected its treatment
potential by the UASB.

11.  Advantages over conventional
treatment ::
 With UASB the aeration the whole
process of settlement and digestion
occurs in one or more large tank(s). Only
the post UASB liquids, with a much
reduced BOD needs to be aerated.
 This leads to a halving of the aeration
energy and a doubling of the power
generated from digestion, leading over
all to a tripling of power generated.

12. CONTACT DETAILS
Vijaya Singh, Indian Institute of Technology Delhi, Hauz Khas,
New Delhi, 110 016, India
vijaya.singhin@gmail.com.
Atul K. Mittal, Indian Institute of Technology Delhi, Huaz Khas,
New Delhi, 110 016, India
akmittal@civil.iitd.ac.in