UNIVERSITI PUTRA MALAYSIA

TREATMENT OF SYNTHETIC WASTEWATER USING HORIZONTAL SUBSURFACE FLOW CONSTRUCTED WETLAND

SANAZ SARAFRAZ

FK 2008 94

TREATMENT OF SYNTHETIC WASTEWATER USING HORIZONTAL

SUBSURFACE FLOW CONSTRUCTED WETLAND

By

SANAZ SARAFRAZ

GS16334

Thesis Submitted to the School of Graduate Studies, University Putra Malaysia, in Fulfilment of the Requirement for the Degree of Master of Science

September 2008

ii

Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfilment of the requirement for the degree of Master of Science

TREATMENT OF SYNTHETIC WASTEWATER USING HORIZONTAL

SUBSURFACE FLOW CONSTRUCTED WETLAND

By

SANAZ SARAFRAZ

September 2008

Chairman: Associate Professor Dr. Thamer Ahmed Mohamed, PhD

Faculty: Engineering

Constructed wetland is an effective wastewater treatment technology which is used

in worldwide. Nevertheless, the effectiveness of using this wastewater treatment is

depending on the selection of the type of design used and other factors. This research

was conduced to test the influence of media and vegetation subsurface flow

constructed wetlands, designed based on the first-order plug flow kinetics. In this

study, four horizontal subsurface flow wetlands (HSSF), each with dimensions of 1.3

m (L) × 0.5 m (W) ×0.4 m (D), were constructed at the Research Station of Tehran

University, located in Karaj, Iran. The study was carried out from April to

September, 2007. Gravel and zeoilte were used in this study as substrate. Gravel-

beds with and without plants, and gravel-beds mixed with 10% zeolite, with and

without plants were examined to investigate the feasibility of treating synthetic

wastewater which was specially produced and modified to imitate agricultural

wastewater. The average synthetic influent wastewater contained approximately 100

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mg l-1 Nitrate (NO3-N), 10 mg l-1 total Phosphorous, 10 mg l-1 Zn (II), 2 mg l-1 Pb (II)

and 1 mg l-1 Cd (II), while the macrophytes selected were Phragmites Australis and

Juncus Inflexus in combine with each other. Water discharge was 65 l / day for each

cell, and retention time (HRT) was 1.4 d. The influent and effluent Zn, Pb, Cd, P and

NO3-N concentrations were monitored and analyzed every 15 days to assess the

performance of the wetland units for removal efficiencies based on the statistical

analyses. Two intermediate samples were also collected from each cell to evaluate

the values of pollutant concentrations, the parameters along the units, and the effect

of the HRT. At the end of the study, plants were harvested and analyzed for the

same factors (NO3, P, Zn, Pb and Cd).

The results derived indicated that the system had acceptable and optimal pollutant

removal efficiency, and that both plants were found tolerant under the tested

conditions. The wetland system could achieve the NO3-N removal of 79.19% in

vegetated cell with gravel and 10% zeolite as substrate, and 86.58% in an

unvegetated cell with gravel and 10% zeolite as substrate, and 82.39% in vegetated

cell with gravel as substrate, and finally 87.94% in unvegetated cell with gravel as

substrate. As for the P removal, the efficiencies of 93.12%, 89.47%, 81.76% and

76.65% were respectively achieved for the vegetated cell with gravel and zeolite as

substrate, the vegetated cell with gravel as substrate, unvegetated cell with gravel and

zeolite as substrate, and unvegetated cell with gravel as substrate. The outflow

concentrations of Pb and Cd were found to be under the detection limit; however, as

for Zn, the removal efficiencies of 99.9%, 99.76%, 99.71% and 99.52% were

concluded for the vegetated cell with gravel and zeolite, unvegetated cell with gravel

and zeolite, vegetated cell with gravel, and unvegetated cell with gravel, respectively.

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Keywords:

Constructed Wetland, Nitrate-Nitrogen, Phosphorus, Wastewater, Zeolite, Zn

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Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai memenuhi keperluan untuk ijazah Master Sains

RAWATAN AIR KUMBAHAN SINTETIK MENGGUNAKAN ALIRAN

MENDATAR PERMUKAAN BAWAH TANAH LEMBAP

Oleh

SANAZ SARAFRAZ

September 2008

Pengerusi: Profesor Madya Dr. Thamer Ahmed Mohamed, PhD

Fakulti: Kejuruteraan

Pembinaan kawasan tanah lembab adalah teknik yang sangat berkesan untuk rawatan

air kumbahan dan telah digunakan dengan meluas diseluruh dunia.

Walaubagaimanapun keberkesanan penggunaan teknik ini bergantung kepada

pemilihan jenis rekabentuk dan beberapa factor lain. Penyelidikan ini telah

dijalankan untuk menguji kesan jenis media dan tumbuhan keatas 4 jenis aliran

mendatar bawah tanah bagi rekabentuk tanah lembab berdasarkan first order plug

flow kinetics. Dalam kajian ini, 4 jenis aliran rekabentuk aliran mendatar bawah

tanah untuk tanah lembab (HSSF), 1.3 m (L) x 0.5 m (W) x 0.4 m (D), telah dibina di

Pusat Penyelidikan, Tehran University yang terletak di Karaj, Iran. Kajian ini telah

dijalankan bermula dari bulan April hingga September 2007. Didalam kajian ini batu

kelikir dan zeoilte telah digunakan sebagai lapisan bawah. Lapisan batu kelikir

dengan tumbuhan dan tanpa tumbuhan, dan juga lapisan batu kelikir yang dicampur

dengan 10% zeolite dengan tumbuhan dan tanpa tumbuhan telah dikaji untuk

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mengkaji kemungkinan merawat air kumbahan sintetik yang dibuat dan diubahsuai

khusus supaya serupa dengan cirri-ciri air kumbahan pertanian. Purata sisa air

kumbahan mengandungi lebih kurang 100 mg 1-1 Nitrat (No3-N), 10 mg 1-1 jumlah

Phosphorous, 10 mg 1-1 Zn (II), 2 mg 1-1 Pb (II) dan 1 mg 1-1 Cd (II), sementara

macrophytes yang dipilih adalah Phyragmites Australis dan Juncus Inflexus

digabungkan bersama. Luahan air adalah 781 d-1 untuk setiap sel dan masa tahanan

hidraulik (HRT) adalah 1.2 d. Kepekatan luahan masuk dan keluar Zn, Pb, Cd, P dan

NO3-N diperhatikan dan dianalisa setiap 15d untuk mengakses pencapaian

kecekapan setiap unit tanah lembab berdasarkan analisa statistik. Dua sampel

perantaraan juga dikutip untuk setiap sel bagi dinilai kadar kepekatan bahan enap

cemar, parameter-parameter unit dan kesan masa tahanan hidraulik (HRT).

Dipenghujung kajian tumbuh-tumbuhan dituai dan analisa keatas NO3, P Zn, Pb dan

Cd dilakukan.

Keputusan yang diperolehi menunjukkan sistem mempunyai tahap penerimaan dan

tahap kecekapan penyingkiran bahan enap cemar yang optimum dan kedua-dua

tumbuh-tumbuhan didapati mampu bertahan dibawah keadaan dimana kajian

dijalankan. Sistem tanah lembab tersebut mampu mencapai tahap penyingkiran NO3-

N sehingga 79.9% dalam sel berbatu kelikir yang ditumbuhi tumbuh-tumbuhan, 10%

zeolite sebagai lapisan strata bawah dan 86.58% dalam sel berbatu kelikir tanpa

tumbuh-tumbuhan serta 10% zeolite sebagai lapisan strata bawah dan 87.94% dalam

keadaan tanpa tumbuh-tumbuhan dengan batu kelikir sebagai lapisan strata bawah.

Tahap penyingkiran P pula ialah 93.12%, 89.47%, 81.76% dan 76.65% masing-

masing diperolehi dari sel dengn tumbuh-tumbuhan dengan batu kelikir dan zeolite

sebagai lapisan strata bawah, sel dengan tumbuh-tumbuhan dan batu kelikir sebagai

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lapisan strata bawah, sel tanpa tumbuh-tumbuhan dengan bati kelikir dan zeolite

sebagai lapisan strata bawah dan sel tanpa tumbuh-tumbuhan dengan batu kelikir

sebagai lapisan strata bawah. Kepekatan luahan Pb dan Cd pula didapati dibawah

tahap yang boleh dikesan, bagaimanapun bagi Zn, tahap kecekapan penyingkiran

sebanyak 99.9%, 99.7%, 99.71% dan 99.52% dapat disimpulkan untuk keadaan sel

masing-masing dengan tumbuh-tumbuhan dengan batu kelikir dan zeolite, sel tanpa

tubuh-tumbuhan dengn batu kelikir dan zeolite, sel dengan tumbuh-tumbuhan

dengan batu kelikir, dan sel tanah tumbuh-tumbuhan dengan batu kelikir.

Kata Kunci:

Tanah lembab yang dibina, Nitrat-Nitrogen, Phosfur, Air kumbahan, Zeolite, Zn

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DEDICATION

I wish to dedicate this thesis to my beloved country, Iran

And

To my parents, Manouchehr Sarafraz and Afsaneh Parhami

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ACKNOWLEDGEMENTS

I am ever grateful to God, the Creator and the Guardian, and to whom I owe my very

existence.

It is a pleasure to thank the people who made this thesis possible.

Firstly I would like to thank my Iranian supervisor Dr. Abdolmajid Liaghat, head of

Irrigation and Reclamation Department of Tehran University, for providing the

opportunity to go on my research in my country, Iran. He always found time to speak

with me offering guidance, support and encouragement in light of his busy schedule.

I would like to gratefully acknowledge the supervision of Dr. Thamer Ahmed

Mohammad during this work. I also thank Prof. Megat Johari as my co-supervisor. I

wanted to specially thank them for being agreed with continuing my research in Iran

and making all necessary supports.

I would like to say a big 'thank-you' to the people of Malaysia whom helped me not

feeling homesick and alone. With their kind and calm faces and many nice places they

gave me a reason to miss Malaysia.

I wish to thank my best friends, Sara, Nooshin and Samaneh, for helping me get

through the difficult times, and for all the emotional support and nice moments we

had in Malaysia together.

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I wish to thank my my brother, Yashar and my sister, Sepideh for providing a loving

environment for me.

Most importantly, I wish to thank my parents. They bore me, raised me, supported

me, taught me, and loved me. To them I dedicate this thesis.

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I certify that an Examination Committee has met on 25th September 2008 to conduct the final examination of Sanaz Sarafraz on her Master of Science thesis entitled “Treatment of synthetic wastewater using horizontal subsurface flow constructed wetland” in accordance with Universiti Pertanian Malaysia (higher degree) act 1980 and Universiti Pertanian Malaysia (higher degree) Regulations 1981. The Committee recommends that the student be awarded the Master of Science. Members of the Examination Committee were as follows: Bujang Kim Huat Professor Faculty of Engineering Universiti Putra Malaysia (Chairman) Azni Idris Professor Faculty of Engineering Universiti Putra Malaysia (Internal Examiner) Abdul Halim Ghazali Associate Professor Faculty of Engineering Universiti Putra Malaysia (Internal Examiner) Hamidi Abdul Aziz Professor Campus of engineering Universiti Sains Malaysia (External Examiner) HASANAH MOHD. GHAZALI, PhD

Professor and Deputy Dean School of Graduate Studies

Universiti Putra Malaysia

Date:

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This thesis was submitted to the Senate of Universiti Putra Malaysia and has been accepted as fulfilment of the requirement for the degree of Master of Science. The members of supervisory committee were as follows: Thamer Ahmed Mohamed, PhD Associate Professor Faculty of Engineering Universiti Putra Malaysia (Chairman)

Megat Johari Megat Mohd. Noor, PhD Associate Professor Faculty of Engineering Universiti Putra Malaysia (Member)

HASANA MOHD. GHAZALI, PhD Professor and Dean

School of Graduate Studies Universiti Putra Malaysia

Date: 18 December 2008

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DECLARATION

I declare that the thesis is based on my original work except for quotations and citations which have been duly acknowledged. I also declare that it has not been previously and is not concurrently submitted for any other degree at UPM or at any other institutions.

……………………..

SANAZ SARAFRAZ

Date: 12 March 2009

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TABLE OF CONTENTS

ABSTRACT II

ABSTRAK V

DEDICATION VIII

ACKNOWLEDGEMENTS IX

DECLARATION XIII

TABLE OF CONTENTS XIV

LIST OF TABLES XVII

LIST OF FIGURES XVIII

LIST OF ABBREVIATIONS XX

CHAPTER I 1

INTRODUCTION 1

1.1 General 1

1.2 Statement of the problem 2

1.3 Objectives of the Study 4

CHAPTER II 5

LITERATURE REVIEW 5

2.1 Natural Wetlands 5

2.2 Constructed Wetlands (CW) 6

2.3 The Functions of Wetland 8

2.4 Advantages of Constructed Wetlands 9

2.5 Limitations of Constructed Wetlands 10

2.6 The Types of Constructed Wetlands 11 2.6.1 Free Water Surface Wetlands (FWS) 11

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2.6.2 Subsurface Flow Wetlands (SSF) 11 2.6.3 The Differences of the FWS and SSF 13

2.7 Wetland Vegetation 14 2.7.1 General 14 2.7.2 Free Floating Macrophytes 15 2.7.3 Submerged Macrophytes 16 2.7.4 Emergent Macrophytes 17

2.8 Wetland Substrate 21 2.8.1 General 21 2.8.2 Soil 21 2.8.3 Sand and Gravel 22 2.8.4 Zeolite 23

2.9 Wetland Micro-organisms 24

2.10 Wastewater 25

2.11 Removal Mechanisms in CWs 28 2.11.1 Nitrogen Removal 28 2.11.2 Phosphorus Removal 35 2.11.3 Heavy Metal Removal 37 2.11.4 BOD Removal 40

2.12 Constructed Wetlands Design 41 2.12.1 General Design 41 2.12.2 The Design Model for the BOD Removal in Subsurface Flow CWs 44 2.12.3 The Design Model for the TSS Removal in Subsurface Flow CWs 44 2.12.4 The Design Model for the Nitrate Removal in Subsurface Flow CWs 45

CHAPTER III 47

MATERIALS AND METHODS 47

3.1 Description of the Site 47

3.2 Design 48 3.2.1 Type of Wetland 48 3.2.2 Wetland Size 48 3.2.3 Aspect Ratio and Slope 49 3.2.4 Inlet and Outlet 49 (c) 54 Figure 3.9 The perspective view of the wetland cell 55 3.2.5 Liners 55 3.2.6 Substrate 55 3.2.7 Vegetation 56 3.2.8 Construction Procedure 57 3.2.9 Wastewater 61

3.3 Methods 63

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3.3.1 Constructed Wetland and Its Variations 63 3.3.2 Wastewater Inflow 65 3.3.3 Wastewater Sampling 67 3.4 Statistical Analysis 68

CHAPTER IV 69

RESULTS AND DISCUSSION 69

4.1 The Overall Performance of the SSF 69

4.2 The NO3-N Concentrations in Inflow and Outflow Wastewater 75

4.3 P Concentrations in Inflow and Outflow Wastewater 80

4.4 Heavy Metals Concentrations in Inflow and Outflow Wastewater 83

4.5 Variations along the SSF CW Length 87 4.5.1 The Variation of NO3-N 88 4.5.2 The Variation of P 90 4.5.3 The Variation of Heavy Metals 92

4.6 NO3, P, Zn, Pb and Cd Concentrations in Substrate 94

4.7 The Concentrations of NO3, P, Zn, Pb and Cd in Plants 96

CHAPTER VI 100

CONCLUSIONS 100

5.1 Conclusions 100

5.2 Recommendations 103

REFRENCES 105

APPENDICES 116

BIODATA OF THE AUTHOR 135

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LIST OF TABLES

Table Page 2.1 Wastewater Characteristics (Metcalf and Eddy, 2005) 27

2.2 Nitrogen transformations in constructed wetlands (Vymazal, 2007) 30

3.1 Karaj fields wastewater characteristics 61

3.2 influent concentrations of artificial wastewater 62

4.1 Meteorological data during the operation period 69

4.2 The Total Concentrations of the Inflow and Outflow, 72

Together with Standard Deviation (S.D.), Range and Removal Efficiency

4.3 T-test Confidence Interval for the Comparison of 75

Mean Values of Inflow and Outflow

4.4 Mean, S.D., Range and Removal (%) of Treatment Values 87

along the Length of the Cells

4.5 Pollutants in the Substrate of Cells 94

4.6 The Amount of Biomass Accumulated in each Cell 96

4.7 The Concentrations and Percentages of Nutrients 97

and Heavy Metals in Plants

4.8 Studied Elements Accumulated in the Plants of each Cell 99

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LIST OF FIGURES

Figure Page 2.1 The Schematic of Constructed Wetland 12

3.1 Wetland Cell 49

3.2 Control Structure (left) and the float (right) 50

3.3 Inlet Zone 51

3.4 Wastewater Container 51

3.5 Outlet Zone 52

3.6 Riser 52

3.7 Pizometers 53

3.8 Plan and Section View of the Wetland Cell 54

3.9 Perspective View of the Wetland Cell 55

3.10 Phragmites Australis (left) and Juncus Inflexus (right) 56

3.11 Akhtarabad Reed-bed 57

3.12 The allocation of the cell 57

3.13 The arrangement of the cell 58

3.14 Substrate Design Stage 59

3.15 Plant Transplanting 59

3.16 The side layout of the wetland 60

3.17 The layout and compartments of CWs 63

3.18 Schematic Plan of the System 64

3.19 Sampling Points in the Cells 67

4.1 Cell’s Contents 70

4.2 A Wetland Cell in the Beginning and at the End of the Operation Period 71

4.3 An opposite View of the CWs at the End of the Operation 71

4.4 Removal Efficiency of NO3-N, P and Zn in A, B, C and D Cells 73

4.5 NO3-N Removal Efficiency 76

4.6 Inflow and Outflow Concentration of NO3-N during the Operation Period 77

4.7 NO3-N Outflow Concentrations in each Cell during the Study Period 78

4.8 P Removal Efficiency 80

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4.9 Inflow and Outflow Concentration of P during the Operation Period 81

4.10 P Outflow Concentrations in each Cell during the Study Period 82

4.11 Zn Removal Efficiency 84

4.12 Inflow and Outflow Concentration of Zn during the Operation Period 85

4.13 Zn Outflow Concentrations in each Cell during the Study Period 86

4.14 Changes in NO3-N Mean Concentration along the Length of the Cells 88

4.15 Changes in NO3-N Concentration along the Length of the Cells. 89

4.16 Changes in P Mean Concentration along the Length of the Cells 91

4.17 Changes in P Concentration along the Length of the Cells in each 91

Sampling Time at 3 Points

4.18 Changes in Zn Mean Concentration along the Length of the Cells 92

4.19 Changes in Zn Concentration along the Length of the Cells in each 93

Sampling Time at 3 Points

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LIST OF ABBREVIATIONS

Abbreviations

BOD

Cd

CW

d

D

EPA

ET

FWS

HLR

HRT

Kt

Kg/g

L

mg

N

NO3-N

°C

P

Pb

pH

ppm

Meaning

5day Biochemical Oxygen Demand

Cadmium

Constructed Wetland

Day

Depth

Environmental Protection Agency

Evapotraspiration

Free Water Surface

Hydraulic Loading Rate

Hydraulic Retention Time

1st Order Rate Constant

Kilogram/gram

Length/Liter

Milligram

Nitrogen

Nitrate- Nitrogen

Degrees Celsius

Phosphorus

Lead

Acidity

Parts Per Million

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PVC

RZE

SSF

TSS

TP

TKN

W

WW

Zn

Polyvinyl Chloride

Root Zone Effect

Subsurface Flow

Total Suspended Solids

Total Phosphorus

Total Kjeldahl Nitrogen

Wide

Wastewater

Zinc

CHAPTER I

INTRODUCTION

1.1 General

There are 80 countries and regions which are experiencing water stress all around the

world; out of which 30 countries are suffering water scarcity during a large part of the

year, and exploiting reserves which are being not sufficiently replaced (Gleick, 1993).

Iran is also going to experience water scarcity by 2025, based on the availability of

less than 1000 m3 of renewable water per person per year (Kivaisi, 2001). The

depletion of reserves and competition for water usage between the nations, as well as

among various sectors such as agriculture, industry and municipalities, has imposed

the major reasons leading to water scarcity.

Iran is a country with an area of 648,000 km², in which arid and semi-arid climate

has covered a great area of the lands. The average of its annual precipitation is about

240 mm, which is less than one third of the average precipitation of the world.

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1.2 Statement of the problem

Due to the occurrence of draught in 2001, population growth, urbanization and

industrial development, the need for water use has been increased in Iran

(Hassanoghli, 2003).

On the contrary to the rising needs, the amount of renewable water resources has

been reduced in the last few years. Statistics shows that this amount was decreased

from 5500 m3 in 1960 to 2100 m3 in 1997, to 1750 m3 in 2005, and this is expected

to be only 1300 m3 in 2020 (Iran Statistical Centre, 2006).

The minimum acceptable renewable water resources demand for a standard life is

2000 m3 per year per capita (Bouwer, 1994). According to water usage amount and

the population increase, the water demand in Iran is expected to be 126×10 9 m3 in

the year 2010, and this will be 150×10 9 m3 in 2020 (Hassanoghli, 2003).

In addition to the natural scarcity of freshwater, the quality of the available freshwater

is also getting worse; this is due to pollution which is a result of water shortage.

Today, it is reported that more than 5 million people die each year throughout the

world from various illnesses because of drinking poor quality water (Kivaisi, 2001).

In Iran, pollution resulting from agricultural wastewater is increased, a scenario which

is harmful for both human being and environment. The main sources of agricultural

wastewater include silage leachate, manure runoff, pesticide runoff and farmyard

runoff. The recognitions of the impacts of these pollutants on the environment have

led to the improvement of wastewater treatment systems.

3

Agricultural and residential wastewaters contain high levels of nutrients and if not

treated, they can contaminate surface water and groundwater systems.

During the last two decades, various experiments have been taken to reduce the

nutrient transport from agricultural activities. The best identified management

practices are increasingly used to reduce the input of nutrients to the agricultural

fields and the leakage from the fields. At the same time, different water treatment

approaches such as wetlands are also used to decrease the transport of nutrients from

land to the sea (Johansson et al., 2004). The management for water usage and water

demand, using recycled water and wastewater, as well as using water and wastewater

treatment programs are some of these solutions.

The treatment of wastewater using constructed wetland is one of the treatment

systems which is used in many parts of the world. This system seems to have the

potential to be one of the solutions in discharging the huge amount of wastes and

getting access to safer drinking water.

Although CWs have not been widely adopted in Iran, they can be preferred system

for wastewater treatment due to the existence of many natural wetlands and

capability of many areas for constructing artificial wetlands to treat different kinds of

wastewaters. They are effective in treating pollutants by combining biological,

chemical and physical treatment processes (Crites, 1994).