Wastewater reuse in agriculture in Vietnam: Water management, environment and human health aspects. Proceedings of a workshop held in Hanoi, Vietnam, 14 March 2001

57 Pages·1.031 MB·English

by  Liqa Raschid-Sally, Wim van der Hoek and Mala Ranawaka, editors

Wastewater Reuse in
WORKING PAPER 30
Agriculture in Vietnam:
Water Management,
Environment and
Human Health Aspects
Proceedings of a Workshop held
in Hanoi, Vietnam
14 March 2001
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Pelawatta Liqa Raschid-Sally, Wim van der Hoek
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Working Paper 30
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Proceedings of a Workshop held in Hanoi, Vietnam
14 March 2001
Liqa Raschid-Sally, Wim van der Hoek and Mala Ranawaka, editors
International Water Management Institute
IWMI receives its principal funding from 58 governments, private foundations, and
international and regional organizations known as the Consultative Group on International
Agricultural Research (CGIAR). Support is also given by the Governments of Pakistan, South
Africa and Sri Lanka.
IWMI gratefully acknowledges the support of the Danish International Development Agency, which
is financing the research on wastewater reuse in Vietnam.
The editors gratefully acknowledge the invaluable support provided by the editing team comprising
Doan Tuan (VIWRR), Phung Dac Cam (NIHE), Anders Dalsgaard and Søren Hansen (KVL),
Flemming Konradsen (University of Copenhagen), and Yutaka Matsuno (Kinki University) and
the authors in preparing and editing the first drafts of the papers.
Liqa Raschid-Sally, Wim van der Hoek and Mala Ranawaka, eds. 2001. Wastewater reuse in
agriculture in Vietnam: Water management, environment and human health aspects. Proceedings
of a workshop held in Hanoi, Vietnam, 14 March 2001. IWMI working paper 30. Colombo, Sri
Lanka: International Water Management Institute.
/ water management / water reuse / waste waters / irrigated farming / agricultural development
/ water law / water resources / rural development / water supply / sanitation / models / software
/ water quality / groundwater extraction / domestic water / reservoirs / public health / disease
vectors / aquaculture / ponds / waterborne diseases / wells / coffee / rice / Vietnam /
ISBN 92-9090-460-7
Copyright © 2001, by IWMI. All rights reserved.
Please direct inquiries and comments to: [email protected]
Cover photograph by Wim van der Hoek: Wastewater irrigated rice fields in Thanh Tri, Hanoi.
Contents
Acronyms .................................................................................................................................. iv
Map of Vietnam ........................................................................................................................ v
Foreword ...................................................................................................................................vii
Wastewater Reuse in Agriculture in Vietnam: Water Management, Environment
and Human Health Aspects.......................................................................................... 1
Denmark–Vietnam Water Sector Program Support ................................................................. 2
Reuse of Wastewater, a Global Perspective............................................................................. 4
Wastewater and its Treatment System in the Southern Part of Vietnam ................................ 6
Impacts of Hoa Khanh Industrial Zone on Bau Tram Reservoir ............................................ 9
Treatment of Domestic Wastewater and its Reuse in Farm Irrigation in
the Red River Delta ..................................................................................................... 11
Wastewater Problems and its Potential to Contaminate Clean Water Sources
in Hanoi........................................................................................................................14
Urbanization and Wastewater Reuse in Peri-Urban Areas: Case Study in
Thanh Tri District, Hanoi City....................................................................................16
Impact of Wastewater on Water Quality in Irrigation System and Treatment Measures
to Reduce Pollution: A Case Study in Nhue Irrigation System..................................18
Wastewater Reuse through Aquaculture in Hanoi: Status and Prospects ...............................20
Sewage Water Aquaculture in Hanoi: Current Status and Further Development...................24
Health Aspects of the Reuse of Wastewater in Agriculture and Aquaculture in Vietnam .....26
Epidemiology of Clonorchiasis in Northern Vietnam .............................................................28
The Microbial Water Quality of the West Lake, Hanoi – Bacterial Indicators......................31
Water Quality in Drilled Wells in Hanoi..................................................................................33
Status of Heavy Metal Pollution of Agricultural Soils and River-Sediments
in Central Hanoi...........................................................................................................35
Annex A: Agenda for Workshop on Wastewater Reuse in Agriculture in Vietnam:
Water Management, Environment and Health Aspects, Hanoi, Vietnam,
14th March 2001...........................................................................................................41
Annex B: List of Participants...................................................................................................43
iii
Acronyms
BOD Biochemical oxygen demand
COD Chemical oxygen demand
DHI Danish Hydraulic Institute
DO Dissolved oxygen
E. Coli Escherichia coli
ha Hectares
HClO Perchloric acid
4
HF Hydro Fluoric acid
HNO Nitric acid
3
IWMI International Water Management Institute
K O Potassium oxide
2
KVL Royal Veterinary and Agricultural University
MPN Most Probable Number
N:P:K Ratio of Nitrogen:Phosphorus:Potassium
NH + Ammonium ion
4
NIHE National Institute of Hygiene and Epidemiology
P O Phosphorus pentoxide
2 5 -
pH Hydrogen ion concentration
SS Suspended solids
TK Total potassium
TN Total nitrogen
TP Total phosphorus
VIWRR Vietnam Institute for Water Resources Research
WAterSPS Water Sector Program Support
WHO World Health Organization
iv
Map of Vietnam
v
vi
Foreword
Wastewater reuse both for agriculture and aquaculture is a centuries old practice in Vietnam and
needs no explanation. However, it was clear from preliminary discussions with our Vietnamese
partners, that no attempt had so far been made to analyze the issues of wastewater reuse for these
purposes in a systematic manner and to document these. In particular, though the potential health
and environmental risks related to reuse are well known in general terms, and the economic costs
and benefits acknowledged, no effort had been made to integrate these key aspects into an analytical
framework which would provide useful information to policy makers in countries like Vietnam,
faced with tough trade-off decisions. What level of treatment do we really need before using
wastewater? What are the likely risks and how can these be offset?
To respond to these questions and as a first step, an inception workshop was organized on 14
March 2001 in Hanoi, gathering experts from the various disciplines such as health, environment,
water resources management, irrigation, agriculture, soil sciences, water quality, etc. to discuss
the findings of 16 papers on different aspects of wastewater reuse. The proceedings of this
workshop are presented here in summary form, which we hope will provide a bird’s-eye view of
the current knowledge in Vietnam on this subject to a wide spectrum of interested persons.
Concrete results from this first situational analysis are a recommendation to carry out a
nationwide survey on the current status of wastewater reuse for peri-urban agriculture and
aquaculture in key cities in Vietnam, and three reviews on foodborne trematode infections,
cysticercosis, and intestinal helminths in Vietnam. These reviews are now underway.
The editors wish to acknowledge the contributions of the various authors and the editorial
board comprising persons from the different partner institutions who helped to edit the papers
into their final format.
These proceedings are the first output of the DANIDA funded project on Wastewater Reuse
for Agriculture in Vietnam. The partner organizations thank DANIDA for their support in funding
the activities under this project.
vii
Wastewater Reuse in Agriculture in Vietnam: Water Management,
Environment and Human Health Aspects
Nguyen Tuan Anh, Director, Vietnam Institute for Water Resources Research
I am very happy for this opportunity to welcome you all at this workshop on Wastewater reuse in
agriculture in Vietnam: Water management, environment, and human health aspects.
Rapid population growth, urbanization and the looming fresh water crisis have increased the
need for wastewater reuse in agriculture in many countries.
In Vietnam, wastewater has been used for centuries by farmers as a cheap and reliable source
of water and nutrients, for agriculture and aquaculture. Nowadays domestic and industrial
wastewater is widely used, especially in the suburban areas. Products from this type of wastewater
reuse are at low cost and contribute significantly to food production in Vietnam.
Despite the widespread reuse of wastewater, its significance has not received adequate
attention. Being a low-income country, Vietnam is unlikely to be able to provide adequate
wastewater treatment infrastructure. Little is known about the use of untreated wastewater in
agriculture, its advantages and limitations, except that it is widespread and unregulated.
Encouraging wastewater reuse in agriculture has important economic and environmental
benefits, such as conserving water and utilizing nutrients. However, using untreated wastewater
also poses certain environmental and health risks, including environmental health risks to users
and consumers of products utilizing wastewater.
To address this situation, with support from the Ministry of Agriculture and Rural
Development, the International Water Management Institute (IWMI), the Royal Veterinary and
Agricultural University (KVL), the Danish Hydraulic Institute (DHI), the National Institute of
Hygiene and Epidemiology (NIHE), the Vietnam Institute for Water Resources Research (VIWRR)
organized a Workshop on Wastewater reuse in agriculture in Vietnam: Water management,
environment, and human health aspects.
Today’s gathering of highly experienced and qualified experts, and researchers is mainly to
share knowledge, information and experience on various issues of wastewater reuse in agriculture
in Vietnam. Such an exchange and sharing of acquired knowledge and skill will help promote
our understanding of issues related to infrastructure of wastewater disposal and treatment systems,
wastewater reuse customs, water and soil quality as well as human health related to wastewater
reuse. For the Vietnam Institute for Water Resources Research this is a unique chance to enhance
its experiences and update its information and knowledge on this important aspect.
I am confident that the participants will make every effort to exchange their respective
expertise. I do hope that the workshop will explore ideas and suggestions for developing research
for wastewater reuse in agriculture in Vietnam effectively.
At this opening ceremony, I, on behalf of the Vietnam Institute for Water Resources Research,
would like to extend a warm welcome to all the distinguished local and foreign delegates, guests,
and participants in this workshop.
May I take the honor to declare open the conference on Wastewater reuse in agriculture in
Vietnam: Water management, environment, and human health aspects.
I wish you all success at this workshop. Thank you.
1
Denmark-Vietnam Water Sector Program Support
Lars Skov Andersen, Sector Program Coordinator, Danida
Introduction
The Water Sector Program Support (WAterSPS) is the umbrella for Danish-Vietnamese
Development Cooperation in the water sector and as such an important interface for the study on
Reuse of Wastewater in Irrigated Agriculture.
Danish Development Assistance to Vietnam
The WAterSPS provides and administers grant assistance to capacity building and implementation
of national sector programs that are given high priority by the Government of Vietnam, and which
concur with the overall policies for Danish development assistance.
WAterSPS
The WAterSPS has four thematic components with a total of 15 Sub-Components defined at the
beginning of program implementation (figure 1). The main objective of the WAterSPS is to support
the implementation of the Law on Water Resources that came into force in 1999, and the National
Rural Water Supply and Sanitation Strategy that was approved by the Government in 2000. These
documents introduce far reaching reforms for the future management of Vietnam’s water resources
and for assistance to improved water and sanitation in rural areas. Components 1, 2 and 3 of
WAterSPS have been designed to support these reforms and implement new procedures at national,
river basin and provincial levels.
Interfaces
The WAterSPS supports the Institute for Water Resources Research, which is the main Vietnamese
counterpart for the Wastewater Reuse Project, and Danida has, since 1993, supported a wide range
of water projects in Dak Lak, which is one of the focus areas of the Wastewater Reuse project.
The WAterSPS support to VIWRR includes the introduction of the MIKE-suite of modeling
software for water resources and environmental management. The modeling tools will enable
VIWRR to assess the impact of wastewater discharges on water quality of receiving waters, and
the potential for reuse in irrigation.
In Dak Lak, the main issue in water resources management is the competition for water
between domestic uses and irrigation of coffee and rice, especially in the plateau surrounding
Buôn Ma Thuôt City. A rapid increase of coffee cultivation since 1992 and extensive abstraction
of groundwater for its irrigation has had a negative impact on domestic water supply for both
rural and urban areas, as well as irrigation of rice, downstream of the coffee areas. In 1994 and
2