b 
PERFORMANCE OF THE EXISTING TRICKLING FILTER 
AT SOYSAPURA HOUSING SCHEME 
By 
S . G. G. Raj kumar 
Department of Civil Engineering 
University of Moratuwa 
Mo ra tuwa,Sri Lanka 
March,1997 
PERFORMANCE OF THE EXISTING TRICKLING FILTER 
AT SOYSAPURA HOUSING SCHEME 
SOMASUNDARAM 6NANAPIRA6ASAM 6ANAN RAJKUMAR 
Thesis Submitted in Partial 
Fulfillment of 
The Requirement for the Degree of 
Master of Engineering in 
Environmental Engineering & Management 
Department of Civil Engineering 
University of Moratuwa 
March, 1997 
67575 
623. ^  
THIS THESIS HAS NOT BEEN PREVIOUSLY 
PRESENTED IN WHOLE OR PART TO 
ANY UNIVERSITY OR 
INSTITUTION FOR A HIGHER DEGREE 
S.GTG. RAJKUMAR 
MARCH, 1997 
ABSTRACT 
Communities living in flats produce both liquid and solid 
waste in large quantities. The liquid waste is called the 
wastewater. This wastewater will be a potential threat to the 
environment. 
Soysapura Housing Scheme treatment plant was taken up for this 
research study. This plant consists of Imhoff tank, trickling 
filter, humus tank and sludge drying beds. In this treatment 
plant performance of trickling filter was selected for 
detailed study. 
Grab samples were taken from inlet of the imhoff tank, 
trickling filter, humus tank and from the outlet of the humus 
tank. Grab samples were taken from 05 30 hrs. to 19 3 0 hrs. 
in two hourly intervals. Sampling was done by having a small 
gap between the first set of sampling and second set of 
sampling with the idea to see any variation in wastewater 
inflow patterns over a period. From the samples collected 
bio-chemical oxygen demand (BOD), chemical oxygen demand 
(COD), suspended solids (SS) and pH were determined. 
The performance of the trickling filter was under detail 
study. A relationship for organic loading and trickling 
filter efficiency was obtained. It was found that the removal 
efficiency improved with increase of organic loading. Also a 
relationship of COD & BOD for the influent of trickling filter 
was obtained. With the loading pattern, the plant could be 
classified as a low rate trickling filter. Also this plant 
could treat further additional load after carrying out the 
suggested improvements. 
The cause of trickling filter performance are discussed and 
areas which require further study and development are 
identified and recommendations are made for future 
investigations. 
ACKNOWLEDGEMENTS 
The author wishes to express his deep gratitude to 
Mr. S. Pathinather, Senior Lecturer of the University of 
Moratuwa and the supervisor of this research for his guidance, 
encouragement and useful suggestions during this research 
study. 
The author acknowledges the assistance and encouragement given 
by Mr. L.S.P.J. De Silva, D.G.M. (Western), National Water 
Supply & Drainage Board (NWS&DB). 
The Cooperation extended by Mr. Melawathanthirige, Manager, 
Colombo Sewerage Operations, NWS&DB, is gratefully 
acknowledged. 
The author is thankful to Mr. Ranatunga, OIC, of the 
Soysapura, wastewater treatment plant for making necessary 
arrangement to collect sample and providing other need full 
assistance. 
The wastewater sample collectors, Mr. Dharmasiri & 
Mr. Piyasiri are gratefully appreciated. 
Sincere thanks are extended to Mrs. Shanthi Hewawasam for 
processing this script. 
The author is thankful to National Water Supply & Drainage 
Board for the facilities provided to carryout this research 
study. 
The facilities provided by the University of Moratuwa are 
gratefully appreciated. 
The author is grateful to Mr. M. Wickramage, Former G.M., 
NWSDB, Dr. S. Buvendralingam, Dr. M. Jayaweera and course 
coordinator Prof.(Mrs).N.Ratnayake for their contributions at 
the presentation prior to writing the thesis. 
The author gratefully appreciates the National Resources and 
Environmental Policy Project (NAREPP) for the financial 
assistance given to carryout this research study. 
Friends & colleagues are gratefully appreciated for their 
encouragement & assistance. 
iv 
TABLE OF CONTENTS 
Page No. 
v 
(I) Abstract i 
(II) Acknowledgement iii 
(III) Table of Contents v 
(IV) List of Figures x 
(V) List of Tables xi 
(VI) Notations xii 
Chapter 1 
1.0 Introduction 1 
1.1 General 1 
1.2 Objective of Sewage Treatment 4 
1.3 History and Types of Attached Growth 
Biological Treatment 6 
1.4 Scope of this Research 9 
1.5 Arrangement of this Thesis 10 
Chapter 2 
2.0 Literature Review and Theoretical 
Consideration 11 
2.1 Fixed Medium 12 
2.2 Reaction & Interaction in Trickling Filter 13 
2.3 Process Design 51 
C h a p t e r 3 
3.0 Methods and Materials 
3.1 Experimental Work 
3.2 Treatment Plant Description 
3.3 Sampling 
3.4 Sundry Information About Soysapura 
Trickling Filter 
C h a p t e r 4 
4.0 Results 
4.1 Relationship Between BOD and COD in the 
Influent to the Trickling Filter 
4.2 Treatment Efficiency 
4.3 Relationship between Organic Loading and 
Removal Efficiency 
4.4 Pattern of Organic Loading 
C h a p t e r 5 
5.0 Discussion, Conclusions and Recommendations 
5.1 Discussion 
vi 
Page No, 
vii 
F 
5.2 Organic Loading and Removal Efficiency 69 
5.3 Present Performance 76 
5.4 Conclusions 78 
5.5 Recommendations 80 
5.6 Recommendation for Further Work 81 
List of References 82 
Appendix A Tabulation of Results 86 
Appendix B Photographs 100 
A. 
LIST OF FIGURES 
Chapter 2 
Figure 2.1 
/ 
Figure 2.2 
Microbial Slime Layer 
Biological Filter 
Page No. 
12 
15 
Figure 2.3 Diagram of Aerobic and Anaerobic 
Sublayer for a Trickling Filter 24 
Figure 2.4 Under Drain Blocks in 
Trickling Filter 33 
Figure 2.5 Typical Cross-Section of a 
Trickling Filter 35 
Figure 2.6 Reaction Type Jet Nozzle 37 
Figure 2.7 
Chapter 3 
Recirculation Patterns 48 
Figure 3.1 Layout Plan of De Soysapura 
Sewage Treatment Plant 55 
Figure 3.2 
Chapter 4 
Figure 4.1 
Figure 4.2 
Figure 4.3 
Figure 4.4 
Details of Trickling Filter 
Relationship between BOD and COD 
for Trickling Filter 
Relationship between Organic Loading 
& Removal Efficiency of 
Trickling Filter 
Diurnal Organic Loading in 
Trickling Filter 
Diurnal Efficiency Variation 
in Trickling Filter 
56 
62 
64 
66 
67 
v i a I 
Chapter 2 
Table 2.1 
Tables 
Typical Information for 
Trickling Filter 
Page No, 
45 
Table 2.2 
Appendix A 
Information on Physical 
Properties of Trickling 
Filter Media 46 
Table 1 
1.1 
1 . 2 
1.3 
1.4 
Results Sample 1 
Sample 2 
Sample 3 
Sample 4 
Sample 5 
86 
87 
88 
89 
90 
Table 2 Average Results 91 
Table 3 BOD and COD Loading in Trickling Filter 92 
Table 4 Ratio of COD/BOD 5 on Average Results 93 
Table 5 Treatment Efficiency on Average Results 94 
Table 6 Efficiency on Individual Results 95 
Table 7 Variation of BOD removal efficiency with 
loading rate in trickling filter 97 
Table 8 Hourly variation of organic loading 
in trickling filter 98 
Table 9 Efficiency variation in trickling 
filter removal 99 
IX 
r 
Notations 
BOD Bio Chemical Oxygen Demand (mg/1) 
cm Centimetre 
COD Chemical Oxygen Demand (mg/1) 
Cu.m Cubic Metre (m3) 
d Day 
hrs. Hours 
Kg Kilogramme 
1 Litre 
min minute 
m Metre 
Q Volumetric Flow Rate (m3/d) 
rev Revolution 
rpm Revolution Per Minute 
Sa Specific Surface Area per unit (m2/m3) 
volume 
Sec Second 
SS Suspended Solid (mg/1) 
T Temperature (°/C) 
V Volume (m3) 
W 7 Surface Area of Filter Medium (m2) 
x