Techniques in post
treatment of ABR
effluents in treating
municipal wastewater
A literature review of appropriate technologies for Nepal
Sanita Dhaubanjar’13
Smith-Princeton Exchange Student 2011
PEI Health Grand Challenge
 Project Title : Study on the water systems and delivery of
water in Kathmandu Nepal
 Organization: Oxford University Clinical Research Unit,
Kathmandu, Nepal
 Project Summary: The project would involve work with the
epidemiology team of OUCRU-NP and the Engineering
Department of Kathmandu City to GIS map all the water
spouts, investigate the water delivery systems, and link this
with the on-going molecular epidemiology of enteric fever in
the city.
Developing a New Project
 Project: Research on Wastewater treatment technologies
 Organisation: Bio-Based and Green Energy Lab (BGEL) at
Kathmandu University (KU)
 Project Advisors:
 Dr Bivek Baral, Coordinator, BGEL
Department of Mechanical Engineering, KU
Email: bivek@ku.edu.np
 Sunil Lohani
Assistant Professor
Department of Mechanical Engineering, KU
Email: splohani@ku.edu.np
Proposed Goals of Study
 Literature review of Anaerobic Baffle Reactor (ABR)
technology to Identify suitable pre and post treatment
technology to supplement ABR as they effluent quality from
ABR does not acceptable standards. Focus on less land
intensive technologies.
 Review different wastewater efmeet fluent standards around
the world, especially in south-Asian countries like Nepal and
suggest acceptable and reasonable effluent standards for
Nepal.
Current status of wastewater
treatment in Kathmandu, Nepal
Dhobighat Wastewater Treatment Plant
Kodku Wastewater Treatment Plant
Status of wastewater treatment
 The 5 centralized WWTP that are not working. All plants
were based primarily on aerobic degradation.
 About 12 communities tried to implement decentralized
Reed Bed Treatment. ENPHO and handful of private
groups invested in constructed wetland based treatment.
 Roughly 370 MLD of wastewater produced in the country
of which the installed WWTP account for only 37 MLD
(10% of total demand)
Identified Problems in Nepal
 Technical inefficiencies
 Blocked sewers due to inadequate flushing and self cleaning
 Lack of filtration or sedimentation as pre-treatment
 Lack of institutional capacity to run WWTP
 Failure to design for combined sewer overflows (CSOs)
 Traditionally preferred system of waste stabilization ponds not favored
because of increased land cost, and advanced systems are not being
constructed because of high capital and operational costs plus lack of
technical expertise.
 Administrative inefficiencies
 Overlapping responsibility between various government sectors in
maintenance of sewer systems.
 Lack of strict monitoring of wastewater discharge.
Anaerobic Baffle Reactor:
Overview
Schematic cross-section of an up-flow ABR. Source: Morel & Diener (2006)
Highlights from review
 Optimal reactor conditions and supplements available in literature to enhance
performance
 Suitable technologies found in literature
 Coagulation-Floccultaion using Zeolite/polymer columns
 Membrane Separation Technologies, espcecially Ultrafiltration
 Aerobic CSTRs
 Submergerd aerated bio-filter
 Dissolved air flotation
 Trickling filter
 Anaerobic filters
 Wetlands and aerated lagoons
 Soil Aquifier treatment (SAT)
 Anaerobic filters
 Down flowhanging sludge filters
 Activated Sludge processes
 UV/H2O2
 Periodic Anaerobic Baffle Reactor for time varying loadings
Other Suggestions
 Wastewater characterization
 Identify and raise awareness about potential reuse of
treated wastewater
 Cost analysis of various combination of wastewater
treatment
 Surveys to understand the interests and knowledge of
communities in managing their own wastes
My Learning experience
 Valuable insight on starting and conducting researches
and literature review
 Increased efficiency in conducting searches using Journal
Search Engines
 Knowledge about wastewater treatment technologies and
their appropriateness
 Status of wastewater treatment in Nepal
 Understand the importance of networking
Acknowledgements
 Dr. Baral and Prof. Lohani at Kathmandu University
 Dr Jeremy Farrar and Nepal’s team at OUCRU
 PEI Health Grand Challenges