Techniques in post treatment of ABR

effluents in treating municipal wastewater

A literature review of appropriate technologies for Nepal

Sanita Dhaubanjar’13Smith-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, BGELDepartment of Mechanical Engineering, KUEmail: bivek@ku.edu.np

Sunil LohaniAssistant ProfessorDepartment of Mechanical Engineering, KUEmail: 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