Table Of ContentThesis No. 059/MSE/309
TRIBHUVAN UNIVERSITY
INSTITUTE OF ENGINEERING
PULCHOWK CAMPUS
DEPARTMENT OF CIVIL ENGINEERING
ARSENIC, IRON AND COLIFORMS REMOVAL
EFFICIENCY OF HOUSEHOLD LEVEL
BIOSAND FILTERS
BY
PREM KRISHNA SHRESTHA
IN PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE DEGREE OF
MASTER OF SCIENCE IN ENVIRONMENTAL ENGINEERING
December, 2004
Lalitpur, Nepal
Thesis No. 059/MSE/309
TRIBHUVAN UNIVERSITY
INSTITUTE OF ENGINEERING
PULCHOWK CAMPUS
DEPARTMENT OF CIVIL ENGINEERING
ARSENIC, IRON AND COLIFORMS REMOVAL
EFFICIENCY OF HOUSEHOLD LEVEL
BIOSAND FILTERS
BY
PREM KRISHNA SHRESTHA
IN PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE DEGREE OF
MASTER OF SCIENCE IN ENVIRONMENTAL ENGINEERING
December, 2004
Lalitpur, Nepal
i
Master of Science Thesis (Thesis No. 059/MSE/309)
ARSENIC, IRON AND COLIFORMS REMOVAL
EFFICIENCY OF HOUSEHOLD LEVEL BIOSAND FILTERS
By
Prem Krishna Shrestha
A thesis submitted in partial fulfillment of the requirements of the degree of
Master of Science in Environmental Engineering
Examination Committee:
_____________________________
(Prof. Dr. Bhagwan Ratna Kansakar) Chairperson
Mr. Mukunda Prasad Neupane Member
Mr. Padma Sunder Joshi Member
Mr. Ram Mani Sharma External Examiner
_____________________________
(Prof. Dr. Bhagwan Ratna Kansakar) Supervisor
Tribhuvan University
Institute of Engineering, Pulchowk Campus
Department of Civil Engineering
December, 2004
Lalitpur, Nepal
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CERTIFICATE
This is to certify that this thesis work entitled "Arsenic, iron and coliforms removal
efficiency of household level biosand filters" submitted by Mr. Prem Krishna Shrestha is a
bonafide thesis work carried out under my supervision and guidance and fulfilling the nature
and standard required for the partial fulfillment of the degree of Master of Science in
Environmental Engineering. The work embodied in this thesis has not been submitted
elsewhere for a degree.
_______________________
(Prof. Dr. Bhagwan Ratna Kansakar)
Supervisor
Institute of Engineering
Pulchowk Campus
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ACKNOWLEDGEMENTS
I am greatly indebted to my thesis supervisor Professor Dr. Bhagwan Ratna Kansakar for
providing me with definite direction, professional guidance, constant encouragement from
the beginning of the work and moral support in many ways during study period.
I am also greatly indebted to Mr. Tommy Kit Kat Ngai, of Massachusetts Institute of
Technology, for his valuable suggestion and direction to accomplish the study.
I would like to thank Mr. Padma Sunder Joshi, Program Coordinator of the M.Sc.
Environmental Engineering Faculty, for providing advice and support during whole study
period. The prompt and quality management of Mr. Joshi is highly appreciable.
I am grateful to Mr. Abadh Kishore Mishra, the chief of Water Quality Monitoring and
Improvement Section of Department of Water Supply and Sewerage, for his excellent
Guidance, Support and Suggestion received during study.
I would like to express my sincere thanks to Dr. Roshan Raj Shrestha, Mr. Bipin Dangol, and Dr.
Suman Shakya, of Environment and Public Health Organization, for their outstanding
suggestions and cooperation received during the study period.
I acknowledge the help, advice and guidance rendered by Head of the Civil Engineering
Department, Mr. Mukunda Neupane, and Lecturer Mr. Ishor Man Amatya. The support
provided by Environmental Laboratory staffs, Mr. Keshav Bhattarai, Ms Prabha Karmacharya
and Ms Goma Yakami is unforgettable.
I am also grateful to all the colleagues of the M.Sc, Environmental Engineering 059 batch.
The cooperation and support of Mr.Diwakar Dhakal, and Mr. Ram Krishna Sapkota is
incomparable and unforgettable!
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ABSTRACT
Experimental investigations were carried out to study the removal of Arsenic, Iron and
Coliforms in drinking water by Bio-sand Filters using Iron nails. Three cycles of experiment
were performed using two Household Filters. The experiments were carried out using
different quality of waters such as arsenic spiked ground water, tap water and natural arsenic
contained ground water. The filters under study consist of two parts combined in a single
unit. The top part of the filter consists of iron nails for the adsorption of Arsenic, while the
bottom part of the filters is basically a small size slow sand filter, which removes the
suspended materials present in water. At the same time it also removes the micro organisms
present in water by biological action.
Both the filters showed moderate results regarding the removal of As, Iron, and Coliforms
during the first cycle of study. First cycle of study was carried out for 32 days using arsenic
spiked ground water of Pulchowk Campus complex, containing very high concentration of
phosphate (31 mg/l).
The performances of filters were found satisfactory in second cycle of study, in which
arsenic spiked tap water was used. Average removal of Arsenic in Filters A and B was 85%
and 76% respectively. Both filters produced water with acceptable concentration of Arsenic
(50 ppb), when the As concentration of raw water was up to 400 ppb and 200ppb in Filters A
and B respectively. When raw water concentration of Arsenic exceeded 400 ppb, the treated
water exceeded the interim standard of Arsenic for Nepal.
The average removal of Arsenic is found about 91%, when tested at Sunawal VDC of
Nawalparasi district.
The efficiency of filters to remove Iron and Turbidity is satisfactory. Iron removal is about
50% in both the filters. But, maximum concentration of 1.75 mg/l of Iron was reduced to 0.2
mg/l. Average turbidity of 12 NTU was reduced to value of less than 1NTU.
Efficiency of filters to remove coliforms is found moderate. Although the coliform removal
percentage is about 94% in both the filters, the quality of water is still doubtful by public
health point of view.
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TABLE OF CONTENTS
Chapter Title Page
Cover page i
Title page ii
Certificate iii
Acknowledgement iv
Abstract v
Table of contents vi
List of figures viii
List of table ix
Abbreviations x
1 Introduction
1.1 General 1
1.2 Microbiologically Contaminated Water 2
1.3 Arsenic Contamination 2
1.4 Remedy for Arsenic Contamination 3
1.5 Objective of Study 4
1.6 Limitation of Study 4
1.7 Organization of the Report 4
2 Literature Review
2.1 Introduction 5
2.2 Environmental Chemistry of Arsenic 5
2.3 Properties of Arsenic 6
2.4 Arsenic in Water 7
2.5 Sources of Arsenic 7
2.6 Human Exposure to Arsenic 8
2.7 Effects of Arsenic on Health 9
2.8 Measurement of Arsenic Concentration 10
2.9 WHO's Activities on Arsenic 10
2.10 Global Situation of Arsenic Contamination 11
2.11 Nepal;s Situation Regarding Arsenic Problem 12
2.12 Drinking Water Criteria for Arsenic 13
2.13 Prevention and Control of Arsenic Contamination 15
2.14 Arsenic Remediation Technologies 15
3 Materials and Methodology
3.1 Study Area 17
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3.2 Experimental Model 18
3.3 Materials Used for Preparation of Filters 19
3.4 Filter Installation 22
3.5 Water for Test 23
3.6 Experimental Methods 24
4 Results and Discussions
4.1 Water Quality Parameters 29
4.2 Arsenic 29
4.3 Iron 38
4.4 Coliforms Removal 41
4.5 Flow Rate 43
4.6 Turbidity 45
4.7 pH 46
4.8 Temperature 46
5 Conclusions and Recommendations
5.1 Conclusions 47
5.2 Recommendations 48
5.3 Area for Further Study 48
References 49
Appendices
vii
LIST OF FIGURES
Figure No Title Page
3.1 Schematic Diagram of Filter A 18
3.2 Schematic Diagram of Filter B 19
3.3 Sieve Analysis of Fine Sand 21
4.1 Arsenic Removal in Filter A (Second Cycle) 32
4.2 Arsenic Removal in Filter B (Second Cycle) 36
4.3 Arsenic Removal in Filters A and B 38
4.4 Flow Rate Profile in Filters A and B 44
4.5 Flow Pattern of Filters A and B 45
4.6 Filter's Flow Rate in Second Cycle 45
4.7 Average Turbidity in Filters A and B 46
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LIST OF TABLES
Table No. Title Page
2.1 Inorganic arsenic speciation in water 6
2.2 Properties of arsenic 6
2.3 Approximate environment concentration level of arsenic 8
2.4 Drinking water quality standard of Nepal 14
3.1 Sieve analysis of fine sand 20
3.2 Characteristics of fine sand 21
3.3 Water quality of raw water 24
4.1 Removal of arsenic in filter A (First cycle) 31
4.2 Removal of arsenic in filter A (Second cycle) 32
4.3 Arsenic removal in filter A (Field test) 33
4.4 Removal of arsenic in filter B (First cycle) 34
4.5 Arsenic removal in filter B (Second cycle) 35
4.6 Influent and effluent of concentration
of arsenic in filter B (Field test) 37
4.7 Profile of iron concentration in filter A (first cycle) 39
4.8 Profile of iron concentration
in Filters A and B (second cycle) 40
4.9 Profile of iron concentration
in filters A and B (Field test) 41
4.10 Coliforms and E-coli in filter A 42
4.11 Coliforms and E-coli in Filter B 42
4.12 Total Coliform removal in Filters A and B 43
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Description:and standard required for the partial fulfillment of the degree of Master of Science in. Environmental Engineering. The work embodied in this thesis has not been
