Developing an appropriate disinfection strategy for post-anaerobic membrane bioreactor effluent
Internship Description
Workshop Description
The current approach to
treat our wastewater relies heavily on aerobic-based treatment technologies and
chlorination, both of which are energy intensive, costly and unintentionally
introduce chemical contaminants to the final treated wastewater. Instead, we
aim to implement anaerobic membrane bioreactor (AnMBR) to clean the municipal
wastewater due to the various advantages associated with anaerobic processes
(e.g. low energy demand, low sludge production and generates methane as an
energy source). However, ammonia are not removed by anaerobic microorganisms
and are typically retained after AnMBR treatment in the range of 20 to 50 mg/L.
The presence of ammonia in the post-AnMBR effluent can be a double-edged sword.
On one hand, it makes the effluent advantageous for direct use in agricultural
irrigation since ammonia can be taken up by plants for growth. On the other
hand, the water cannot be disinfected with chlorine to prevent microbial
regrowth as the direct use of chlorine on such ammonia-rich waters will produce
nitrogenous disinfection byproducts (e.g. N-nitroso NDMA), which have been
shown to be carcinogenic and mutagenic.
Considering the problems associated with chlorine, we therefore propose that
post-AnMBR effluent be treated with UV/H2O2 (a form of advanced disinfection
process) as a final disinfection. This study aims to optimize a UV/H2O2 plug
flow reactor to disinfect post-AnMBR effluent. To achieve this, parameters such
as reactor configuration, UV intensity, concentrations of hydrogen peroxide and
contact time will be optimized. Turbidity of the post-AnMBR effluent will be
monitored as increase in turbidity will result in poor UV efficacy due to light
scattering and limited light penetration. pH will also be monitored as it
affects the formation of nitrate and reactive oxygen species from H2O2. All
parameters will be correlated with the log removal values of an appropriate
tracer compound. This will allow one to determine the range of acceptable
operating conditions and water quality permissible in a continuous UV/H2O2
system. Energy costs associated with the disinfection will be collated for
techno-economic analysis of the system
Deliverables/Expectations
Deliverables
An optimized disinfection
process for post-anaerobic membrane bioreactor effluent
Faculty Name
Peiying Hong
Student Monthly Allowance
$1,000.00
Field of Study
Field Of Study
Disinfection processes