Paraphrasing, revision and conclusion ( Constructed wetlands for treating industrial wastewater )

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timer Asked: May 9th, 2018
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Question description

i need you to paraphrase chapter 1 for me its about 6 pages no need to paraphrase the objectives , keep it the same

potential revision, you already worked with chapter 3 ( Methodology ) and chapter 4 ( Results and discussion )

i have sent the work to the supervisor and I'm waiting for feed back, you might fix some of the work and there is a possibility to add more case studies

add conclusion, it should be very good and conclude the work in a very good and professional way

please be careful of the plagarism

Tutor Answer

LesserGenius
School: University of Maryland

Attached.

Page 1

Name:
Paper title:
Institution:
Date:

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Table of Contents
Chapter 1 ......................................................................................................................................... 3
1. INTRODUCTION ...................................................................................................................... 3
1.1background ................................................................................................................................. 3
1.2 Limitations of Constructed Wetlands ....................................................................................... 6
1.3 Problem Statement .................................................................................................................... 7
1.4 Objectives ................................................................................................................................. 8
1. Review of constructed wetland designs for municipal wastewater: ....................................... 8
2. Review of constructed wetland designs in oil and gas industries: .......................................... 8
3. Review of constructed wetland designs for individual/single households:............................. 8

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Chapter 1

1. INTRODUCTION

1.1background
Water is one of the key elements we all need for survival. Healthy life not only receives
facilitation from other things but also this thing we call water. It is helps living and non- living
organism achieve good and proper healthy life. Water is part of all elements that help in
supporting life. It is beneficial to both living organisms and non-living organism in its
sustenance. Water is something no human being can do without; this is one of the core reasons
we humankind have a huge mandate of protecting all water resources. Despite these efforts of
securing our sources, water pollution is one of the big problems threatening the survival of water
bodies. In as much as it seems impossible in protection of these water bodies, it is still a mandate
we humans have to fulfill in order for us to live.
Pollution of water is being affected majorly by untreated industrial discharge inclusive of
municipal wastes. In summary, the environment is highly affected by these wastes (Postel, 2000)
and our household’s wastes that are set out to draw into our water sources. This menace can only
be curbed by educating the public on sensitization and the importance of looking after these

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resources generally. If the society continues with this bad habit of neglecting water resources and
not bothering to protect them, we will end up having future predicaments that nothing can be
done to protect it. Discharging of industrial wastewaters in our water bodies remains to be the
biggest problem we suffer from and we will suffer from all through.
A prediction has already been done, that this pollution of water bodies will really affect
us dearly in the near future, this demands us to start solving this future nightmare before worse
comes to worse. It is no longer something that we do not know but fully aware, this amounts to
negligence. What can be done is to educate the public at large on the importance of protecting
water bodies and be made enforceable (Postlel,2000) in that it not only remains us a talk but
something that is actualized. These public education tutorials should entail things such as the
importance of recycling, managing what one can have, in that people should not only rely on
having so much so as to survive but learn to manage. In as much as we can say that this might
fail just as other means have, it remains as our last hope. It is obvious and very right to conclude
that indeed the discharge of industrial waste interferes with not only our water bodies but also the
environment in general.
It is an establishment that, water recycling from the wetland treatment system actually
does saves as a huge chunk of money in areas with scarce water. Wastewater wetlands is
something tht has really helped people in the society in saving water. To solve this water
nightmare in such areas, farming ought to be practiced and development of proper and better
sewerage system to avoid the problem of water scarcity. In as much as it might not really cut this
problem, at least it will help in prevention of further problems developing in regards to water
scarcity. Public sensitization ought to be adopted for purposes of helping in curbing and
preventing this problem affecting us. Besides having to conduct public awareness, this is also

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one of the ways to help in setting out the message to the public the need of preserving our water
bodies inclusive of the water reservoirs.
It is evident various organizations are standing out trying to end the problem at hand.
However, I still advocate for the creation of public awareness in order to reach a bigger number.
This will help in better conservation of water simply because the initiative of reaching everyone
will be achieved. We humans ought to prioritize what we put our money into, one of this thing
remain to be conserving water. Integrating our money into these areas will highly help in saving
human lives. By saving water sources, it not only is beneficial to us humans but also the
environment at large. Failure of preserving our water bodies will sure amount to degradation of
the environment that is a habitat to many in the society. Water is a daily need that we all need to
survive this life. Not minding ones standard, race, tribe or even background we all need water in
our lives. It is the core reason we are advocating for saving water bodies is something many
organizations are fighting for. It is out of negligence that people decide to spoil the few water
resources we have and not making any effort on preserving them.
“Sustainability is a concept that can be integrated into human activities as well as the
entire human society” (Calheiros, Rangel, & Castro, 2007). sustaining is crucial area that major
focus has been put on. As it is clear, a wider group is slowly exhausting the amount of water they
have, this leaves them with no option, but recycling and conserving water already exists in their
society. This is the only way that will help them deal with this menace slowly creeping into their
lives. Lack of water simply means loss of lives. Interference of public water by addition of
known and unknown water constituents is something that is highly practiced.

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CW is set to exploit the physical among other treatments that occurs in wetlands and
provide for the reduction in organic material among other organisms. This system is cost
effective and very easy to maintain, in addition to the aforementioned the system is easy to
operate. It is highly applicable in households and industries due to its nature of easy operation
and maintenance.

1.2 Limitations of Constructed Wetlands
Constructed Wetlands core goal remains to be a system for municipal, industrial, and
single household wastewaters approach. However, they have limitations that undermine the
system effectiveness in the landscape. Constructed wetlands water waste system is set in a way
that use larger pieces of land as opposed to other wastewater systems in as much as they are used
for the same purpose. This nature makes it very convenient for areas with available land space at
affordable rates (Díaz, Anthony, & Dahlgre, 2012).
This system becomes very costly for persons who have no lands and are left with no
option but purchasing. One of the reasons why some areas have not adapted this wastewater
system as it is rendered expensive.(Jhansi,& Mishra 2013) This system of wetlands is not
advisable in dry areas as they are less effective in such conditions. Building and installing the
system becomes so much a task. This system is also highly affected by heavy rains upon
occurrence more so during spring seasons. In conclusion, we can say that in as much as it serves
its purpose of protecting the water resources, it is highly affected by weather changes easily
(Imfeld, Braeckevelt, Kuschk, & Richnow, 2009). This gradually undermines its effectiveness to
fulfill the main purpose.

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The only technology that can improve the preceding statement is still underdeveloped.
For attainment and sustainment of the effectiveness of this system, more should be done in
relation to improving the system and other surrounding bodies.

1.3 Problem Statement
Industrial, municipal, and single household wastewater management is problem in so
many developing countries worldwide. This is due to the hardship in finding a low cost
wastewater management technology for application of producing effective effluents to meet all
this needed function. By having this wastewater, management helps in prevention of disease
spread and infections. Wastewater management is something that has to be at the forefront of
every person thoughts globally (Vymazal, 2010).
The main goal for developing the wastewater treatment systems is to help in water
conservation inclusive of other environmental resources. All the harmful that come because of
this discharges ought to be handled well to avoid any harm. This is to enable us handle and
prevent the spread of diseases and any infections to the members of the public at large. Pollution
of water is a dangerous thing as it brings up so many risks not only to the human but also to the
environment. We all are aware mosquitoes best environment is water, more so stagnant polluted
water. Existence of mosquitoes clearly tells us a larger number of people contacting malaria
(Healy, Rodgers, & Mulqueen, 2007).
Construction of wetlands has highly helped in conservation of huge pieces of land that is
costly at certain given times.

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1.4 Objectives
This paper study mainly discusses the performance, percentage removal, and water
balance of assorted designs of the constructed wetlands treatment system for the use of treating
wastewater. It is evident this project is meant to help in water bodies preservation in the society.
In as much as it might be hard to adopt this means in areas with scarce land, it is something the
government should really enforce as one of the mechanisms.
1. Review of constructed wetland designs for municipal wastewater:
Influent/effluent quality, different designs, reuse criteria, examples – case studies

2. Review of constructed wetland designs in oil and gas industries:
Influent/effluent quality, designs, reuse criteria, examples - case studies

3. Review of constructed wetland designs for individual/single households:
Onsite wastewater treatment, influent/effluent quality, different designs, reuse criteria, examples
- case studies

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References
Calheiros, C., Rangel, A., & Castro, P. (2007). Constructed wetland systems vegetated with
different plants applied to the treatment of tannery wastewater. Water research, 41(8),
1790-1798.
Díaz, F., Anthony, T., & Dahlgre, R. (2012). Agricultural pollutant removal by constructed
wetlands: Implications for water management and design. Agricultural Water
Management, 104, 171-183.
Healy, M., Rodgers, M., & Mulqueen, J. (2007). Treatment of dairy wastewater using
constructed wetlands and intermittent sand filters. Bioresource technology, 98(12), 22682281.
Imfeld, G., Braeckevelt, M., Kuschk, P., & Richnow, H. (2009). Monitoring and assessing
processes of organic chemicals removal in constructed wetlands. Chemosphere, 74(3),
349-362.
Vymazal, J. (2010). Constructed wetlands for wastewater treatment: five decades of experience.
Environmental science & technology, 45(1), 61-69.

Attached.

Running Head: CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT 1

ENG 4 133 Bachelor Thesis
German University of Technology in Oman (GUtech)
Department of Engineering

Constructed Wetland for Wastewater Treatment

Course Coordinator:
Dr.-Ing. Najah Al Mhanna
Project Supervisor:
Team Members:

CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

Approval of the Dean of the Faculty of Engineering and Computer Science

Dr.-Ing. Najah Al Mhanna

I certify that this Thesis satisfies the requirements of a Bachelors Thesis for the Degree of
Bachelor of Engineering in XXX Engineering.

Dr.-Ing. Najah Al Mhanna
Head, Department of Engineering
I certify that I have read this Thesis and that it is my opinion that the Thesis is fully adequate in scope and quality as a Bachelors Thesis for the Degree of Bachelor of XXX Engineering

Name
Supervisor
Examining Committee
1. Name
________________________________

2

CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

2. Name
________________________________

3

CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

ABSTRACT
Sustainable treatment of water using constructed wetlands translates to a more efficient
waste management system that is cheaper in terms of the cost of capital and the mechanical technology required especially in domestic cases. Either way, constructed wetlands
provide an effective alternative to industrial and municipal wastewater treatment as well.
The concept of constructed wetlands was first practically applied in Australia and has
now received worldwide attention as more and more scientists show interest in the treatment method. Constructed wetlands allow for wastewater to be purified in the most natural way while avoiding the use of harsh chemicals used in conventional wastewater
treatment methods and hence sustaining and improving the environment while eliminating the effects of water pollution. There are different CW designs and structures that can
be applied for domestic, municipal, and industrial wastewater management that are discussed and compared from a range of case studies to determine their advantages, disadvantages, and which is the best option to apply for various treatment needs in the world
today.
Keywords:
Wastewater
Constructed wetlands
Wastewater treatment
Plant species
Industrial wastewater
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CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

ACKNOWLEDGMENTS

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CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

Contents
ABSTRACT ................................................................................................................ 4
ACKNOWLEDGMENTS ........................................................................................... 5
LIST OF TABLES ...................................................................................................... 8
LIST OF ABBREVIATIONS OR SYMBOLS ........................................................... 9
1.
1.1

INTRODUCTION ............................................................................................ 11

Background ............................................................................................................................ 11

1.2

Limitations of Constructed Wetlands..................................................................................... 14

1.3

Problem Statement ................................................................................................................. 15

1.4

Objectives............................................................................................................................... 16

2.1

Domestic, Municipal and Industrial Wastewater ................................................................... 17

2.2

Conventional Wastewater Treatment ..................................................................................... 19

2.2.1

Conventional Wastewater Treatment Process ........................................................................ 19

2.3

Constructed Wetlands ............................................................................................................ 22

2.4

Advantages of Constructed Wetlands .................................................................................... 23

2.5

The Main Benefits and Outcomes of the Constructed Wetlands ........................................... 24

2.6

Types of Constructed Wetlands ............................................................................................. 24

2.7

Components of Constructed Wetlands ................................................................................... 25

2.7.1

Water ...................................................................................................................................... 25

2.7.2

Substrates, Sediments, and Litter ........................................................................................... 26

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CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT
2.7.3

Vegetation .............................................................................................................................. 27

2.7.4

Microorganisms ..................................................................................................................... 28

2.7.5

Animals .................................................................................................................................. 28

2.8

Literature Summary ............................................................................................................... 29

3.

METHODOLOGY .......................................................................................... 30

3.1

Overview ................................................................................................................................ 30

3.2

Treatment Of Effluents With Significant Amounts Toxic Heavy Metals ............................. 31

3.3

Treatment Of Wastewater With Insignificant Or No Amounts Of Toxic Heavy Metals ..... 38

4.

RESULTS AND DISCUSSION ..................................................................... 43

4.1

Treatment of Effluents With Significant Amounts Of Heavy Toxic Metals ................... 43

4.2

Treatment of Effluents with Insignificant Or No Amounts Of Heavy Toxic Metals ..... 51

4.3

Comparison and Summary ................................................................................................. 59

4.4

Recommendations ................................................................................................................ 61

5.

CONCLUSION ............................................................................................... 62

References .................................................................................................................. 64

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CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

LIST OF TABLES
1. Table 1…………………………………………………………………………………...43
2. Table 2…………………………………..……………………………………………….45
3. Table 3……………………………...……………………………………………………46
4. Table 4…………………...………………………………………………………………52
5. Table 5…………………………………………………………………………………...56

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CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

LIST OF ABBREVIATIONS OR SYMBOLS
CW

Constructed wetlands

BOD

Biochemical oxygen demand

COD

Chemical oxygen demand

TDS

Total dissolved solids

pH

Potential of hydrogen

DO

Dissolved oxygen

TC

Total coliform

FC

Fecal coliform

TSS

Total suspended solids

SS

Suspended solids

MRP

Molybdate Reactive Phosphate

HSF

Horizontal surface flow

HSSF

Horizontal subsurface flow

FWS

Free water surface

EP

Emergent plants

SP

Sub-emergent plants

FFP

Free floating plants

FLP

Floating leaved plants

SSF

Subsurface flow

VF

Vertical flow

VSF

Vertical surface flow

VSSF

Vertical subsurface flow

HF

Horizontal flow

HCW

Hybrid constructed wetland
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CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

FMR

Filtralite MR 3–8

HUSB

Hydrolytic up-flow sludge bed

BCF

Bio-concentration factor

STP

Sewage Treatment Plant

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CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

Chapter 1
1. INTRODUCTION

1.1 Background

Among the most vital elements that contribute to the creation and sustenance of a good, proper
and healthy life not only in living organisms but non-living organisms as well, is water. Water is
a crucial element on planet Earth because it supports life. For this reason, it is wise for mankind
to protect all water resources since water in all countries across the globe, is considered as an invaluable element which man cannot do without. Water pollution is a major environmental hazard
that is continuously imposing threats not only to the environment but to the water bodies as well.
Exhaust fumes and industrial wastes are to a large extent contributing to pollution of water. Discharging untreated industrial, single household and municipal wastes into water resources and on
land have facilitated the degradation of the environment and the members of the public are on the
threat of contracting health-related complication as a result of water pollution. Generally, untreated industrial, municipal and single household wastes interfere with the public health and the
environment at large (Postel, 2000).

Public sensitization on the need of preserving water resources should be enhanced in order to try
and curb water pollution as a result of municipal, industrial and single household wastewaters.
Once the people are educated on the importance of protecting water reservoirs then avoiding wa11

CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

ter pollution and environmental degradation will be avoided. It is predicted that in the near future, the adversities associated with water pollution and environmental degradation will be so
dire to the extent that, competition for the limited water resources among the members of the
public would be inevitable. In order to prevent future predicaments, therefore, education is vital
and is something that the relevant authorities should enforce among the population of a given
geographical location (Postel, 2000). The people who are worst hit by the predicament of water
scarcity can be educated on how to use the little they have, and water recycling should be enforced so as the people can embrace that. Water recycling from the constructed wetland treatment system for industrial, municipal and single household wastewaters saves money among the
population struggling with the scarcity of water. Improving farming practices and the sewerage
system should be encouraged in order to avoid the issue of water scarcity from escalating any
further. There are organizations globally that encourage clean water initiatives in regions facing
water scarcity. Advance water conservation technologies are initiatives designed to help in the
water conservation strategies globally. Despite the existence of organizations and support groups
that encourage the conservation of water, more world population should be reached in order to
enable them to conserve water better. Human lives can be saved if money and effort are integrated into the water conservation process. The strategy of conserving water not only benefits the
society but also benefits water utilities and the environment as well.

Sustainability is a concept that can be integrated into human activities as well as the entire human society (Praewa, 2017). Once human activities are less sustainable then there would be adverse effects on the ecosystem which is crucial for sustenance and support of human life. Modern
approaches have been designed to integrate sustainability, environmental ethics and the partici12

CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

pation of public efforts in coming up with developmental projects in the society. Some world
communities are exhausting the little water resources that they have and as a result, water recycling and conservation would be an ideal approach to help deal with such an adversity.
In most cases, known and unknown water constituents are added in the public water which is
used for commercial, domestic and even industrial use and as a result of the constituents addition, the public water ends up to be municipal, single household and industrial wastewaters.
Construction of a sustainable wetland for wasteland treatment is an approach for municipal, single household and industrial wastewaters, which would best act as a basis for water reclamation
and reuse in most sustainable water resources management programs across the globe (Praewa,
2017).

Constructed wetlands (CW) are engineered and managed wetland systems that are increasingly
receiving worldwide attention for wastewater treatment and reclamation. They are systems that
naturally occur, pollutant removing process mediated by complex interactions between water,
soil/gravel media, vegetation and their associated microbial assemblages and the environment to
improve water quality in a sustainable way. CW are designed to exploit the physical, chemical,
and biological treatment processes that occur in wetlands and provide for the reduction in organic material, total suspended solids, nutrients, biological oxygen demand, metals and pathogenic
organisms. Constructed wetlands are cost-effective and easily operated and maintained, and they
have a strong potential for application in households, municipal and industries.

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CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

1.2 Limitations of Constructed Wetlands

Just like any other new municipal, industrial and municipal wastewater approach, the Constructed Wetlands systems for municipal, industrial and single household wastewaters have limitations
of their own that undermine their effectiveness in the landscape. They make use of larger pieces
of land unlike other conventional wastewater systems used for the same purpose. Therefore the
approach would only be suitable in places where land is available in large quantities and at very
affordable rates. In this case because of the economic deficits it has, it is not a cost-friendly approach to those people who have no large tracts of land or have no money to buy more land for
the construction of the wetlands; and hence in some case the Constructed Wetland system is too
much a task because of its expensive nature (Jhansi, & Mishra, 2013). . Since biological components are in most cases sensitive in nature to chemical, then any water surges would definitely
undermine the effectiveness of water treatment. As much as the wetlands are designed in a way
that can survive in very minimal amounts of water, they cannot survive completely in a dry area
or rather they are not engineered to survive in trying circumstances. Very cold weather conditions do undermine the effectiveness of the wetland system and high temperatures that may come
as a result of dry spells and drought, affect the effectiveness of the system too. Conversely,
heavy rains also affect the effectiveness of the constructed wetland systems most especially during the spring season. The system is susceptible to the many changing weather patterns and
therefore their effectiveness in the treatment process for municipal, industrial and single household wastewaters is gradually undermined (Crawford, & Sandino, 2010).
The use of constructed wetland systems for municipal, industrial and single household
wastewaters is a relatively new concept and for this reason, the technology which supposedly can
be used to enhance its effectiveness is underdeveloped. Some ecological and environmental cri14

CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

tiques argue that more should be done in order to attain fully effectiveness of the industrial, municipal and single household constructed design system.

1.3 Problem Statement

Many developing countries are faced with the challenge of industrial, municipal and single
household wastewater management because they have problems finding low-cost wastewater
management technologies that can be used in the application of producing the most effective effluents in order to meet single household, municipal and industrial functions. Wastewater management holds the sole purpose of preventing the spread of diseases and infections. Nutrients recovery, water reclamation, and reuse as well as conserving water resources are other wastewater
management goals that most world organizations are trying to achieve. A shift from conventional
wastewater management to more sustainable wastewater management should be embraced globally (Praewa, 2017).

This is because once the shift has been achieved then there would be conservation of water and
environmental resources and this is the overall goal of many wastewater treatment systems. In
this sense, this report is intents to make a full analysis and assessment of the constructed wetlands systems in enhancing the quality and effectiveness of wastewaters and the associated environmental risks and threats that may come to light as a result of wetlands. The effluents and discharges that come as a result of water pollution should be handled well so as not to spread diseases and infections to the members of the public. There are so many hazardous effects of the
water pollution to the environment and to the general health of individuals. Mosquitoes breed
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CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

well in stagnant polluted water bodies, and as a result, the people might be at a higher risk of
contracting malaria, which is a deadly disease if not treated most especially in infants and children under the age of five years. Some wastewater systems have the tendency of clogging and
overflowing on surfaces (Praewa, 2017). Constructed wetlands, unlike other conventional
wastewater systems, utilize huge pieces of land which can be costly sometimes.
1.4 Objectives

Design of Constructed Wetland for municipal and industrial applications:
This study discusses the design, performance, percentage removal and water balance of assorted
designs of the constructed wetlands treatment system for the use of treating wastewater.
1. Review of Constructed Wetland designs for single households – onsite wastewater treatment,
influent/effluent quality, different designs, reuse criteria, examples - case studies
2. Review of Constructed Wetland designs for municipal wastewater – influent/effluent quality,
different designs, reuse criteria, examples – case studies
3. Review of Constructed Wetland designs for the oil and gas industry – influent/effluent quality,
designs, reuse criteria, examples - case studies

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Chapter 2
2. LITERATURE REVIEW

2.1 Domestic, Municipal and Industrial Wastewater

In this time and age, the issue of municipal, industrial and single household wastewater is of
great concern because it causes severe environmental problems to the environment and it also
affects people in terms of their health. Municipal, industrial and household wastewaters are environmental related issues whose negative impacts affect, all living organisms, whether it’s animals, human beings or the environment. Studies have approximated that wastewater is exactly
99% water while the remaining 1% is a mixture and combination of suspended, dissolved organic solids, detergents and also a mixture of chemicals (Secretariat, 2014). A single household,
municipal and industrial wastes are types of wastewaters.

Sewage” is one kind of waste water. Household wastes from toilets, kitchen sinks, and showers
are constituents of sewage and are disposed of via sewers. Municipal wastewaters commercial
inputs range from photofinishing shops, restaurants, and car washes as well as bars recreational
facilities (Secretariat, 2014). Frequently, pretreated industrial wastewaters constitute the municipal wastewaters flow. A wide variety of process and facilities that consists of Plastic manufacturing wastes, pulp, petroleum refineries and food processing, results in the formation of industrial
wastewaters.
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CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

According to Secretariat (2014), different types of wastewaters (single household, municipal and
industrial) have varying chemical compositions, for instance, pathogens, bacteria, and nutrients.
Wastewaters untreated components can be organized in three categories which include physical,
biological and chemical components. Solid and inorganic constituents in the wastewaters are
what comprise the physical components. Biological components in wastewaters are made up of
bacteria, viruses, protozoa and other pathogens in the wastewaters. Lastly, chemical components
are made up of dissolved and organic matters as well as nutrients and metals which in most cases
are heavy metals.

In rare cases, industrial, municipal and single household wastewaters might contain reusable resources, for example, carbon, water, and other nutrients which could be recovered or reused in
other cases. For effective effluent regulatory standards to be met and be satisfactory then, the
wastewater will need to be treated in order to get rid of all water pollutants which might be found
in the municipal, industrial and single household wastewaters and should undergo appropriate
treatment (Crawford, & Sandino, 2010). According to Crawford & Sandino (2010), the
wastewater treatment process should be focused on the recovery of resources so as to be selfsustaining.

Water engineers and scientists have been on the edge trying to figure out the most appropriate
technologies which would be embraced to ensure the effectiveness and efficiency of treatment
systems are achieved and all this has been attributed to the critical issues which are exhibited in
the wastewaters. The most known and basic systems of single household, municipal and indus18

CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

trial wastewaters treatment are integrated into the reduction of organic water compounds and the
suspension of solids so as to attain the needed effluent regulatory standards. With noticeable
progression in the advancement of new technologies by water engineers and environmental scientists, a wastewater treatment approach has been developed in order to help in the absorption
and removal of dissolved toxic substances and organic matter from the wastewaters.

Advancement in the scientific knowledge and consciousness about the environment and water
bodies have given rise to new and improved technologies and treatment systems as well which
are quite helpful in curbing pollution in wastewaters and also reduce the energy used in the recycling of the industrial, single household and municipal wastewaters. Therefore, while selecting
the appropriate technology to help in solving the wastewater problem, great care and caution
should be considered. Generally, there are two types of wastewater treatment systems and they
are the conventional wastewater treatment and the sustainably constructed wetlands treatment
system.

2.2 Conventional Wastewater Treatment
2.2.1 Conventional Wastewater Treatment Process
Conventional wastewater treatment process is made up of physical, chemical and biological processes. This treatment process encompasses three stages which are referred to as the primary,
secondary and tertiary treatment.

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2.2.2 Primary Treatment

This treatment is used in the removal and the separation of inorganic materials as well as solids
which would otherwise clog and destroy water pipes. This type of treatment entails screening,
grit removal, and sedimentation. Screens in this treatment are used to get rid of large debris
which includes plastic and cans. Grit chamber system is used to remove and settle sand and
gravel. According to Nelson et al (2007), the wastewater is moved into the quiescent basin, with
a temporary retention, and then eventually heavy solids settle at the bottom of the basin while
lighter solids, grease as well as oil move to the upper surface of the quiescent basin. Finally,
skimming and sedimentation processes are used to both the settled and floating pollutants in the
wastewaters then the liquid which remains is transferred and discharged so as to pass through the
secondary treatment. 50% of the total suspended solids, 30%- 40% of BOD are gotten rid of in
this stage (Nelson et al, 2007).

2.2.3 Secondary Treatment

Dissolved and biological matters are removed by use of secondary treatment. According to Nelson et al (2007), 90% of organic matter in the wastewater is removed through biological treatment process at this stage. Attached growth processes and suspended growth process are the best
two suitable conventional methods used in the secondary treatment.

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Normally in the attached growth processes, the algae, bacteria and other microorganisms grow
on the surface and as a result, biomass is formed. Trickling filters, bio towers, and rotating biological contactors are all inclusive in the attached growth process unit. There is a suspension in
microbial growth in an aerated water mixture in the suspended water processes. However, activated sludge is the most common type of suspended water processes. The activated sludge process typically grows a biomass of aerobic bacteria and other microorganisms that are essential in
the organic waste breakdown.
2.2.4 Tertiary Treatment

Tertiary treatment is a more advanced form of the treatment. Compared to primary and secondary treatment, tertiary treatment is used in the production of high and quality effluent and discharge in a bid to discharge in the too fragile ecosystem like estuaries and low-flow rivers. Tertiary treatment is purposefully used in the provision of the last and final treatment stage so as to
achieve the targeted and desired levels of the raised effluent quality. Coagulation sedimentation,
filtration, reverse osmosis, and extending secondary biological treatment are some of the methods that can be achieved through the advanced tertiary treatment. These methods are further used
to remove nutrients and stabilize oxygen in more oxygen-demanding substances. Treated effluent
can then be safely reused and recycled because of the higher and advanced degrees purification
of wastewaters (Praewa, 2017).

Under most familiar circumstances, disinfection process is needed before treated wastewater is
discharged. Once disinfectants are added to the water systems, then the pathogens and microor21

CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

ganisms found in the water are killed. The treatment of wastewaters makes use of disinfection in
order to minimize the number of microorganisms and pathogens in the water before the water
can be discharged back into the environment and regardless of the water treatment used, this is
normally the final treatment process. Chlorine and ultraviolet lights are amongst the most known
and common methods used in the disinfection of water. The treated water can then either be discharged into different water bodies or be used in agricultural irrigation (Praewa, 2017). The
treated water can be used for agricultural use or underground water recharge should the water
meet the required set standards.
2.3 Constructed Wetlands

Constructed wetlands (CWs) design systems for single household, municipal and oil and gas are
a type of wastewater treatment system which is designed and structured in ways that imitate the
natural process of wetlands. Unlike another treatment process that occurs in nature in wetlands,
this system has advantageous aspects. Constructed wetlands for a single household, municipal
and oil and gas incorporate chemical, biological and physical processes that are used in the enhancement and improvement of the quality of water and the removal of pollutants in the water
(Vymazal, & Kröpfelová, 2008). These design systems which have macrophyte aquatic microbial communities and plant roots and supporting mineral matter are of great benefit and effective in
the pollutants from wastewaters and these pollutants include, nitrogen, metals, pathogenic organisms among many others.

In 1904, the first ever constructed wetland was built in Australia. The technology advancement
within the field of constructed wetlands is still under-developed in spite of the fact that the con22

CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

structed wetlands have been in existence for over a century (Vymazal, & Kröpfelová, 2008). As
the increase of constructed wetlands continues across the world, it is continuing to find favor
among many ecologists, scientists and even water and environmental engineers because of its
many benefits as compared to the traditional treatment processes. Many people prefer constructed wetlands over the other conventional treatment systems because of the benefits and effectiveness of the system and due to these reasons; it is getting popularized even among developing
countries globally.

2.4 Advantages of Constructed Wetlands

Constructed Wetlands design systems for industrial, municipal and single household wastes, are
not only a cost-friendly but they are also effective in the treatment of wastewater and runoffs.
Constructed wetlands for municipal, industrial and single household wastewaters are helpful in
the facilitation of water reuse and reclamation in many regions globally (Postel, 2000). They also
act as habitat for the many wetlands’ organisms. In addition, Constructed Wetlands is an environmental-sensitive approach that has been admired and accepted by the members of the public
since they are designed in a way that fits perfectly in the environmental landscape.

Structured and managed water systems like the constructed wetlands (CW), is a system that is
receiving major global attention because of its effectiveness in industrial, household and municipal wastewater reclamation and reuse. By embracing Constructed Wetland systems, the quality
of water, microbiological assemblages, and the environment is gradually improved. Through this
23

CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

system, storm water runoffs, domestic wastewater, and industrial wastewater is used to best help
in the treatment of petroleum refinery wastes, pretreated industrial wastewater, and fish pond
wastewater; and once the wastewaters are treated then their adversity on the public water system
and the environment is reduced (Vymazal, & Kröpfelová, 2008). Constructed Wetlands in most
cases are structured in a way that determines the physical, biological and chemical water treatment processes that naturally occur in the wetlands, are responsible for organic materials reduction and are also responsible for the provision of the high biological oxygen demands.

2.5 The Main Benefits and Outcomes of the Constructed Wetlands

The constructed wetland is a beneficial wastewater system for the municipal, industrial and single household because, upon treatment, the water that is discharged can either be used for domestic activities or can be directly discharged to the environment. It is also beneficial to the endusers as the construction cost is minimal, the cost of operation and the maintenance cost is affordable. The maintenance and the operation of the constructed wetlands are periodic, unlike
other conventional water treatment system which in most cases require continuous, on-site labor
(Crawford &.Sandino, 2010) The constructed wetland design system for municipal, industrial as
well as single household, facilitates the recycling and reuses of water and saves the cost. The
constructed system not only provides a habitat for the wetland organisms but it is engineered in a
way that it finds favor in the eyes of mankind because of its many benefits.

2.6 Types of Constructed Wetlands

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CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

They are various types of constructed wetland design systems for municipal, industrial and single
household wastewaters depending on the landscape. The types include; surface flow (SF) and
subsurface flow (SSF). SF constructed wetlands have shallow flow and have a lower velocity
above with substrates. The SSF wetlands flow either vertically or horizontally in the substrates.
Therefore SSF constructed wetlands can be further categorized into horizontal and vertical flows.
Hybrid constructed wetlands is a combination of both the vertical and horizontal flows
(Vymazal, & Kröpfelová, 2008). Each type of the constructed wetland design system for an industrial, municipal and single household has its own benefits and downsides as well. These types
of constructed wetlands differ in the treatment process. The SF-CWs makes use of plant stems as
well as leaves and rhizomes in order to effectively treat the water effluents. In dense vegetation,
however, the process can be limited because there would be no enough circulation of oxygen
which is vital for organic animals and organisms. In the SSF-CWs, the roots are used in the
treatment of effluents as water passes through a series of gravel beds. This process is considered
superior and effective to SF-CWs.
2.7 Components of Constructed Wetlands
2.7.1 Water

Places where landforms in most cases direct surface water straight into shallow basins, as well as
other places where impermeable subsurface layers hinder the ground from absorbing surface water, are the most likely places where wetlands can form. Such conditions in a place can be designed to engineer the creation of wetlands (Jhansi, & Mishra, 2013). A land can be structured in
the way that collects surface water and seals all the basins in order to retain the surface water col-

25

CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

lected and once all these modifications have been done to a landscape then a wetland can be
properly structured of constructed.

In the construction of wetlands systems for industrial, municipal and single household
wastewaters, hydrology is among the most important factors that should be put into consideration. This is because it not only links all wetland functions but it also is a key factor in the failure
or the success of a given constructed wetland on a landscape. The hydrology of constructed wetlands is important when compared to the hydrology of other surface water. Small hydrological
changes naturally, exhibit significant effects on a wetland and the effectiveness of the whole
treatment as well. Through rainfall and evapotranspiration, there is a great interaction between
the wetland system and the atmosphere and all these happen because of the waters' shallow depth
and large surface area. Hydrology in most cases is also affected by the wetland vegetation density and this is because of the obstruction of water flow paths and exposure to sun and wind blockage.

2.7.2 Substrates, Sediments, and Litter

Soil, sand, gravel, rock as well as other organic materials for instance compost, are what constitute up substrates. Due to the high wetland productivity and low water velocities, accumulation
of sediments and litter into the wetland is made possible. In a wetland, substrates, sediments, and
litter are of great and vital importance and this is because, they support all the living organisms
that dwell in the wetlands (Secretariat, 2014). For many contaminants in the wetland, substrates
act as a storage source for them. Another importance of the substrate is that its permeability af26

CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

fects the movement of the water passing through the constructed wetland. As a result of the accumulation of litter in the wetland, the amount of organic matter is gradually increased.

2.7.3 Vegetation

In any constructed wetland for municipal, industrial and single household wastewaters, the presence of both vascular plants and non-vascular plants are of vital importance (Praewa, 2017). The
vascular plants are the higher plants whereas the non-vascular plants are the algae. Once the algae undergo through photosynthesis, then there is an increase in the rate of dissolved oxygen
content found in the water. Therefore the increase of the dissolved oxygen contents in the water
effects to a larger extent the metals and all nutrients in the wetland. Plants are very important and
this is because they facilitated the transportation of oxygen to the roots of the plants. The presence of plants in a constructed wetland system, therefore, is very important since it penetrates the
soil structure and transfers oxygen even further deeper into the soil, a process which would not
be possible and achievable even by use of diffusion.
The presence of the submerged leaves, stalks and litter in their submerged portions are important
to FWS wetlands because of attached microbial growth, then the leaves, stalks, and litter have to
serve as substrates. The wastewater wetlands in most cases are frequented by the absence of
emergent plants in the systems and among the emergent plants that are mostly found in the wetland systems include; reeds rushes, bulrushes and cattails. Cattails, however, have the capability
of thriving and surviving in the most diverse environmental conditions. Production of large annual biomass is also a capability that has been achieved by the cattails.

27

CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

When it comes to bulrushes, all rush these rushes are considered to be perennial and grass-like
herbs that are capable of growing and thriving in clumps. They tend to grow better in water that
ranges from 5cm to 3metres deep (Wetzel, 1993). Most bulrushes grow well in a PH of 4-9.
Reeds are tall annual grasses with a perennial rhizome. Amongst the most widespread emergent
aquatic plants are reeds. Wetlands that decide to use reeds are at an advantage because the reeds
have the capability of transferring oxygen and hence the effectiveness of the system is improved.
2.7.4 Microorganisms

The functions of wetlands are in some way regulated and controlled by the presence of the microorganisms and their metabolism. Algae, protozoa, fungi, and yeast are examples of microorganisms found in the wetlands. Microbial activities in the system are important because they are
used in the recycling of the nutrients. The microbial activities also affect the processing capacity
of the wetland because they interfere with the reduction of substrate conditions. In a constructed
wetland, the microbial community is affected by toxic chemicals like pesticides (Wetzel, 1993).
2.7.5 Animals

Some vertebrates and invertebrates have found a habitat in the constructed wetlands system. Insects and worms are examples of the invertebrate animals whose contribution towards the treatment process is of significant importance (Wetzel, 1993). They are considered as beneficial animals which make the treatment process not only to be safe but also effective.

28

CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

2.8 Literature Summary

Constructed wetlands designs for municipal, industrial and single household wastewaters system
can be designed in the most appropriate and specific way possible so as to meet the intended
purpose. Municipal, industrial and single household wetland systems can be engineered in order
to take advantage of the different site features to avoid any disturbances while at the site. Industrial, municipal and single household wastewaters can be constructed on a private piece of land
so as to avoid any uncertainties associated with the developing technologies of constructed wetlands. Public land is mostly not suitable for the construction of wetlands designs for municipal,
industrial and single household wastewaters. However before any construction is done, the interest groups should be incorporated in generation of inputs for the wastewaters system. Single
household wastewaters system is of economic importance to householders and this is because
less energy is used in the system operation. Constructed wetlands for treatment of municipal and
industrial effluent are an effective wastewater approach that should be embraced globally in order to help in the reuse and reclamation of water.

29

CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

Chapter 3

3. METHODOLOGY

3.1 Overview
The methodology section of this paper offers an insight into the various methods used to design appropriate and suitable CWs for optimal performance. Various parameters such as size,
30

CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

area, flow design, capacity, vegetation type, wastewater type, cell structure and components
are crucial to the success of a CW and hence these case studies provide accurate information
about the above mentioned parameters. The section also shows different methodologies for
CWs for different types of wastewater including domestic wastewater, agro-industrial
wastewater, and mine wastewater. The structures for each type of wastewater are different in
size and design based on the components contained. As such, the methodologies are unique
for each case study.

3.2 Treatment Of Effluents With Significant Amounts Toxic Heavy Metals
Industrial Wastewater Treatment using Reed bed Constructed Wetland
The first step carried out in this study involves the testing of wastewater samples from a battery industry for toxic metals. Two pilot VSF experimental wetlands measuring 1200mm by
600mm are then constructed, the first to measure retention period of the reed plants Phragmites karka and the second to observe the removal efficiency rate. The first bed is planted
with wetland vegetation and substrates while the second bed, a control bed, is only filled with
wastewater and substrates only without a reed plant. The reed cuttings are planted 150mm
apart and then irrigated in 40 liters potable water for ten days so as to make sure they grow
quickly and properly before introducing the wastewater. The supply of wastewater adopts
vertical subsurface flow. The retention periods of the two beds are then recorded between 319 days. Effluents are then analyzed for toxic metals in comparison to the analysis results of
untreated wastewater. After the pilot experiment, two reed beds are constructed in 1000 liter
plastic tanks measuring 1200mm by 1000mm by 600mm. 450mm of granite makes the bot31

CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

tom layer while 150mm of washed sand makes the top layer. Similar to the pilot experiment,
the first bed is planted with reeds while the second is not planted with any vegetation. Industrial wastewater is harvested from Elewi-Odo stream and the influent is drained in 3, 7, 11,
15, and 19 days for both beds (Sangola, Aribisala, & Awopetu, 2015).
Wetlands for Industrial Wastewater Treatment at the Savannah River Site
The CW under study is located in South Carolina and its objective is to treat copper, lead,
mercury, zinc, BOD, pH, trichloroethylyne, tetrachloroethylyne, oil, grease, total residual
chlorine, total suspended solids and chronic toxicity. The system consists of two 90 foot by
484 foot cells divided into four separate treatment trains and a solar powered flow monitoring
station. The wastewater which includes storm water moves through the cells by gravity. The
materials used to construct the cells are inert in order to avoid leaching of metals and any
other contaminants into the influent and effluent. Prior to the building of the actual CW,
bench-scale and on site pilot scale models are constructed to test the efficacy of the method
of wastewater treatment and the suitability of the design of the CW. The vegetation chosen
for the CW is bulrushes, which are required to transplanted into the CW early enough to mitigate the effects of climate stress and transplant shock for successful growth in the CW
(Lehman, et al.). The design’s performance is highly dependent on constant monitoring of the
flow management basin to manage optimal performance capacity during both high flows and
low flows. The flow management basin should be maintained at near empty during high
flows when rainfall is heavy. During low flows, a minimum base flow of approximately 0.3
million gallons of wastewater per day should be run through from the process stream. Water
depth in the CW cells is monitored to determine redox potential. In addition, hydrosoil samples are collected and analyzed regularly to determine their suitability for bulrush growth.
32

CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

The Use of Constructed Wetlands for the Treatment Of Industrial Wastewater
The case study explores the various types of CW based on the flow type. There are two main
types of CWs that are then further broken down into more specific types. FWS CWs are constructed in such a way that the wastewater flows above a substrate medium which forms a
free water surface and a water column depth of about a few centimeters (Skrzypiec & Gajewska, 2017). FWS CWs are either vegetated with EP, SP, FFP, or FLP. The second type of
CW is SSF CWs which entails wastewater flowing through a porous substrate. SSF CWs are
then classified depending on whether the flow is vertical or horizontal. Finally, the different
CW designs can be combined to form a hybrid system (HCW).


The petrochemical industry produces wastewater that consists of ammonia, oil and

grease, SS, phenolics, hydrocarbons, heavy metals, organics and H2S. An example of a CW
that treats petrochemical wastewater for hydrocarbon contamination is one in Amoco’s Mandan, North Dakota (Skrzypiec & Gajewska, 2017). The wastewater flows from an oil separator and a lagoon measuring 6ha in area into the CW. The CW itself is made of 11 ponds totaling an area of 16.6ha.


The pulp and paper industry wastewater contains organic matter, and SS although the

components vary with type of process, technology, amount of water used in the process, type
of wood material, and internal recirculation of the effluent for the purposes of recovery
(Skrzypiec & Gajewska, 2017). Western Kenya hosts a pilot scale CW used to remove phenols from wastewater. The HSSF CW was operated for 15 months under various HRTs with
batch loading.

33

CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT



A lab scale CW was used to treat steel wastewater from a metallurgical industry. Two

VSSF beds were constructed, one filled with manganese ore and the other filled with gravel.
The monitored parameters were iron, manganese, turbidity, TP, and COD (Skrzypiec &
Gajewska, 2017). In Taiwan, In Taiwan, a HSSF mesocosm for treatment of steel mill
wastewaters was filled with gravel, planted with common reed and bulrush and operated at a
HLR of 2.6 cm∙d–1 and HRT of 7 days (Skrzypiec & Gajewska, 2017).


Textile industries produce wastewater containing dyeing chemicals, dyes, and textile aux-

iliaries. Since only 47% of the dyes are biodegradable the removal of color from wastewater
is a major challenge (Skrzypiec & Gajewska, 2017). CWs with the common reed species are
used to treat the wastewater.


Cases of an alcohol fermentation industry (winery) use the HSSF CWs and hybrid (HF-

VF) CWs. Direct feeding of winery wastewater with high concentration organic compounds
into CWs often shows limits in the tolerance of wetlands and have a serious negative effect,
such as clogging which reduces oxygen infiltration into the growth media and typically causes rapid failure of the wetland system (Skrzypiec & Gajewska, 2017). Therefore, HSSF and
hybrid CWs are used because of their passive nature. Sometimes the wastewater is treated
first before being pumped into the CW.


A slaughter house wastewater HSSF CW (food processing industry) in New Mexico...

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