









































Pa
ge

 
1



Pa
ge

 
7

American Journal of   
Environment and Climate (AJEC)

Suitability of  Grey-water Treated with Common Reed in Constructed Wetland for 
Irrigation Purposes in Akure, Nigeria

Femi Alao1, Adewoye Alade Olanipekun1*, Ajayi Johnson Oloruntade2, Oluwatosin Onaopemipo Olofintoye3, 
Afolabi Matthew Oke4, Daniel Uwumarogie Idusuyi1,Opeyemi Bayode1, Quadri Opeyemi Saka5, Damilare Akintunde Ojewole5

Volume 4 Issue 2, Year 2025
ISSN: 2832-403X (Online) 

DOI: https://doi.org/10.54536/ajec.v4i2.4503
https://journals.e-palli.com/home/index.php/ajec

Article Information ABSTRACT

Received: February 02, 2025
Accepted: March 08, 2025

Published: May 07, 2025

Effective grey-water management plays a crucial role in promoting environmentally sustain-
able practices. This research focuses on assessing the suitability of  grey-water treated with 
common reed for irrigation purposes in Akure, Nigeria. Grey-water samples were sourced 
from a university hostel and subjected to treatment through a Constructed Wetland (CW) 
system, which was planted with common reed (Phragmites australis). The study spanned 
a three-year period (2016-2018), during which both the physico-chemical and microbial 
parameters of  the raw and treated grey-water were evaluated before and after treatment. 
The findings revealed notable reductions in the treated grey-water’s physico-chemical and 
microbial characteristics, thereby indicating the effectiveness of  the treatment process. Ad-
ditionally, the levels of  heavy metals in the treated grey-water were significantly reduced, 
meeting the World Health Organization (WHO) standards for safe use in irrigation. The 
study highlights the potential of  common reed-based constructed wetlands to effectively 
remove contaminants from grey-water, underscoring their viability as a low-cost, eco-friend-
ly solution for grey-water treatment in Akure, Nigeria, and similar regions. The study also 
concludes that common reed-treated grey-water can be a viable alternative for irrigation in 
agricultural settings, contributing to sustainable water management practices in areas like 
Akure. Consequently, the treated grey-water from this system is deemed safe and suitable for 
agricultural use, aligning with guidelines for wastewater reuse in irrigation.

Keywords
BOD, COD, Common Reed, 
Constructed Wetland, Grey-Water, 
Water Treatment

1 Department of  Civil and Environmental Engineering, Bells University of  Technology Ota, Nigeria 
2 Department of  Agricultural and Bio-Resources Engineering, Federal University, Oye-Ekiti, Nigeria 
3  Department of  Water Resources and Environmental Engineering, University of  Ilorin, Ilorin, Nigeria 
4  Department of  Agricultural and Bio-Systems Engineering, Bells University of  Technology, Ota, Nigeria
5  Department of  Mechanical Engineering, Bells University of  Technology, Ota, Nigeria
* Corresponding author’s e-mail: aaolanipekun@bellsuniversity.edu.ng

INTRODUCTION
The composition of  grey-water directly mirrors household 
activities and is shaped by factors such as living standards, 
cultural and social practices, household size, and the choice 
of  cleaning products (Oladejo & Olanipekun, 2018). Grey-
water from sources like showers, bathtubs, and hand-
washing sinks usually contains fewer contaminants, while 
water from laundry and dishwashing often has elevated 
phosphorus levels due to detergents. Kitchen grey-water 
is typically the primary source of  nitrogen, whereas 
grey-water from bathrooms and laundry generally has 
lower nitrogen concentrations (Olanipekun et al., 2024). 
The rising global production of  grey-water is raising 
environmental concerns, highlighting the importance of  
treating it for reuse. Historically, wastewater treatment is 
primarily aimed to ensure safe disposal, thereby reducing 
risks to public health and preventing environmental harm 
(WHO, 2006).
However, the purpose of  wastewater treatment has 
evolved to also emphasize resource recovery, including 
the extraction of  energy, nutrients and water from waste. 
Still, the core objective remains the safe discharge of  
both domestic and industrial effluents, ensuring they do 
not pose health hazards or cause significant harm to the 
environment (Aiyelokun et al., 2024a). Utilizing wastewater 

for irrigation provides two significant advantages: it not 
only offers a method of  waste disposal but also promotes 
resource recovery by reusing water in productive ways. 
This practice is particularly beneficial when applied in 
slow-rate land treatment processes, where wastewater is 
gradually absorbed and utilized by plants and soil systems. 
Despite these advantages, raw municipal wastewater 
is typically unsuitable for direct use in agricultural 
irrigation, landscaping, or aquaculture without undergoing 
preliminary treatment (Aiyelokun et al., 2024b).
The degree and quality of  treatment are essential for 
determining how effectively wastewater can be integrated 
into soil-plant systems or aquatic environments, as they 
influence the health and sustainability of  these ecosystems 
.Inadequate treatment can compromise the performance 
of  these systems, underscoring the importance of  proper 
wastewater treatment before agricultural use (Metcalf  
& Eddy, 2003). With the growing strain on global water 
resources, the treatment and reuse of  wastewater offer a 
sustainable solution that helps preserve the environment, 
while also reclaiming valuable resources. The quality 
standards for treated wastewater intended for irrigation 
depend on several factors, such as the specific crops 
being cultivated, the characteristics of  the soil, and the 
method used to apply the treated effluent (Oladejo, 2014; 



Pa
ge

 
8

https://journals.e-palli.com/home/index.php/ajec

Am. J. Environ. Clim. 4(2) 7-14, 2025

Olanipekun & Idusuyi, 2023). Selecting crop types or 
irrigation techniques that lower health risks can potentially 
reduce the level of  treatment required before wastewater 
is applied.
This position was affirmed by Ghosh and Chakraborty 
(2025), in a reported study which utilized water hyacinth 
(Pontederia crassipes) as a carefully selected wetland 
plant for adapting agricultural practice in Bangladesh 
to the deleterious effects of  climate change. The study 
found that water hyacinth was instrumental coping with 
salinity, drought, water logging and flooding in selected 
farmlands across Bangladesh. However, this strategy is 
less feasible for aquaculture, where stricter wastewater 
treatment protocols are necessary to ensure safety for 
both aquatic organisms and human health. Aquaculture 
systems require higher water quality standards to 
prevent contamination and to maintain a healthy aquatic 
environment, making advanced treatment essential in 
these settings. This will not only guarantee success when 
the entire process is completed, but will also ensure that 
another environmental challenge is not inadvertently 
created in a bid to solve an already existing one.
According to Metcalf  & Eddy (2003), the ideal form of  
wastewater treatment for agricultural reuse should ensure 
the effluent meets recommended microbiological and 
chemical standards, while also being cost-effective and 
requiring minimal operational complexity and maintenance 
(Gholipour et al. 2020). Constructed wetlands (CWs) that 
incorporate common reed (Phragmites australis) offer an 
affordable and eco-friendly approach to treating grey-
water, largely due to their minimal design, construction, 
and maintenance costs. These engineered wetland 
systems capitalize on natural purification processes, 
making them an effective and sustainable method for 
improving water quality. CWs work by combining several 
mechanisms to remove contaminants from wastewater. 
Physical processes, such as filtration and sedimentation, 
help separate particles and impurities, while biological 
activities, including microbial breakdown and nutrient 
absorption by plants, aid in reducing pollutants (Li et al. 
2020; Sijimol & Joseph, 2021).
Additionally, various chemical reactions, such as 
precipitation and adsorption, further enhance the system’s 
capacity to purify grey-water. Collectively, these processes 
enable CWs to reduce harmful substances in wastewater, 
supporting a low-impact, resource-efficient treatment 
strategy (Kadlec & Knight, 1996). Typically, these systems 
are equipped with impermeable clay or synthetic liners 
and structures that help control flow direction, water 
retention time, and water levels. Furthermore, some 
setups may utilize inert porous materials such as rocks, 
gravel, or sand. Similarly, vegetation within constructed 
wetlands serves an essential function in the treatment 
process, contributing significantly to the system’s overall 
effectiveness. Plants not only provide oxygen to the 
rhizosphere, a zone of  intense biological activity around 
their roots but also create a supportive environment for 
the beneficial microorganisms residing there. This oxygen 

transfer helps maintain aerobic conditions in parts of  the 
wetland bed, promoting microbial processes that break 
down pollutants.
Also, the vegetation actively absorbs nutrients from the 
wastewater, which reduces nutrient loads that might 
otherwise lead to issues like eutrophication if  discharged 
untreated into natural water bodies. The plants’ roots, 
stems and leaves also expand the available surface area for 
microbial colonization, facilitating more sites for microbial 
communities to thrive and carry out pollutant-degrading 
processes (Oladejo & Olanipekun, 2018). In this way, 
plants are central to the wetland’s ability to function as 
a self-sustaining water treatment ecosystem, enhancing 
both nutrient cycling and contaminant removal (Brix, 
1993). In summary, these constructed wetlands aim to 
enhance the physical, chemical, and biological functions 
of  natural wetlands to decrease levels of  biochemical 
oxygen demand (BOD), total suspended solids (TSS), 
total nitrogen (TN), phosphorus, and pathogens as 
wastewater flows across the vegetated surface (Reed et al., 
1987; Reed, 1993).
It is therefore important to mention that when choosing 
plants for CWs, important factors to consider are their 
tolerance for waterlogged and low-oxygen conditions, 
their capacity to thrive in nutrient-rich settings, their 
ability to absorb pollutants, and their adaptability to 
harsh climatic conditions. While over 150 species of  
macrophytes have been utilized in CWs worldwide, 
only a few are frequently employed in practice 
(Vymazal, 2013). The most commonly used emergent 
plants include Phragmites spp. (Poaceae), Typha 
spp. (Typhaceae), Scirpus spp. (Cyperaceae), Iris spp. 
(Iridaceae), Juncus spp. (Juncaceae), and Eleocharis spp. 
(Spikerush). Common submerged plants include Hydrilla 
verticillata, Ceratophyllum demersum, Vallisneria natans, 
Myriophyllum verticillatum, and Potamogeton crispus. 
Floating-leaved species often used are Nymphaea 
tetragona, Nymphoides peltata, Trapa bispinosa, and 
Marsilea quadrifolia, while free-floating plants include 
Eichhornia crassipes, Salvinia natans, Hydrocharis dubia, 
and Lemna minor (Kumar et al., 2008; Akhtar, 2017).
Emergent macrophytes are more efficient in removing 
pollutants and are better adapted to handle various 
wastewater sources (Napaldet & Buot, 2019; Said et al., 
2021; Beauclair, 2021). A survey by Vymazal (2013) on 
emergent plants in free water surface (FWS) constructed 
wetlands found that Phragmites australis is the most 
commonly used species in Europe and Asia, while Typha 
latifolia dominates in North America, Cyperus papyrus 
in Africa, P. australis and Typha domingensis in Central 
and South America, and Scirpus validus in Oceania. 
Additionally, Vymazal (2011) reviewed plants in subsurface 
flow (SSF) wetlands and reported that P. australis is the 
most widely used species globally, especially in Europe, 
Canada, Australia, and large parts of  Asia and Africa. 
Wetland plants play a crucial role in enhancing water quality 
in constructed wetlands, serving as the primary biological 
component. These plants aid in purification processes by 



Pa
ge

 
9

https://journals.e-palli.com/home/index.php/ajec

Am. J. Environ. Clim. 4(2) 7-14, 2025

facilitating the removal of  nutrients and directly absorbing 
nitrogen, phosphorus, and other nutrients (Liu et al., 2011; 
Zu et al; 2020; Ko, 2024).
Similarly, they have the capacity to accumulate harmful 
substances, including heavy metals and antibiotics (Liu et 
al., 2013). For instance, Wu et al. (2013) found that four 
emergent wetland plants absorbed between 6.50 - 26.57 g 
N/m² and 0.27–1.48 g P/m² when treating polluted river 
water. The ability of  plants to uptake nutrients differs 
depending on several factors, including system design, 
retention time, loading rate, type of  wastewater, and 
climate (Saeed & Sun, 2013). In general, plants can help 
remove between 15% to 80% of  nitrogen and 24% to 
80% of  phosphorus from the wastewater (Greenway & 
Woolley, 2001), though some studies show lower removal 
rates, such as 14.29 - 51.89% for nitrogen and 10.76 - 
34.17% for phosphorus (Wu et al., 2013). In the case of  
emerging contaminants, plants have been effective in 
removing substances like carbamazepine, sulfonamides, 
and trimethoprim from wastewater (Dordio et al., 2011; 
Dan et al., 2013). For heavy metal removal, Eleocharis 
acicularis demonstrated strong accumulation capabilities 
for metals like Ag, Pb, Cu, Cd, and Zn (Ha et al., 2011) 
and Yadav et al. (2012) found that metal accumulation 
was higher in below-ground biomass than above-
ground biomass. Despite significant research efforts, this 
approach is still relatively new in Nigeria, indicating a 
need to examine the suitability of  grey-water treated with 
common reed for irrigation purposes.

MATERIALS AND METHODS
The research was conducted behind Jadesola Akande 
female hostel on the Obanla campus of  the Federal 
University of  Technology (FUTA), Akure, Ondo 
State, Nigeria. Akure is located at Latitude 7°14’ N and 
Longitude 5°08’ E. The region experiences a tropical 
humid climate, marked by two distinct seasonal patterns 
(rainy and dry). Suffice it to say that all of  the experiments, 
from wetland planting to water treatment, were carried 
out in the dry seasons of  December to February of  2016, 
2017 and 2018. Influent grey-water was sourced from a 
hostel, where water from showers, bathtubs, kitchens, 
and bathroom sinks was directed into a system designed 
for initial filtration and pretreatment. This water traveled 
through pipes with a diameter of  128 mm to reach a 
filtration tank, where a preliminary filtration process 
removed larger suspended particles as shown in Figure 1. 
Items such as food debris, hair, and lint were screened out 
using a layered filtration medium composed of  various 
sizes of  gravel specifically layers with particles smaller 
than 32 mm, 24 mm, and 16 mm and capped with a fine 
sand layer of  0.2 mm in diameter for finer filtration.
After this pre-filtration stage, the partially treated grey-
water was conveyed through a narrower, 32 mm diameter 
pipe into the constructed wetland as illustrated in Figure 
2. This wetland was set up with a similar combination 
of  gravel and sand as the filtration tank, but included 
the addition of  common reed (Phragmites australis), a 

plant selected for its effectiveness in aiding the treatment 
process as shown in Figure 3. In the wetland system, the 
grey-water was retained for a period of  two days, allowing 
for further purification through the combined effects of  
microbial action, plant uptake, and sedimentation within 
the substrate. Following this retention time, the processed 
effluent, now treated grey-water, was collected and ready 
for potential reuse or safe discharge. Water samples were 
taken from two sources: raw grey-water and treated 
grey-water, both were collected in sterilized laboratory 
bottles from the study site for analysis. The parameters 
evaluated included physical factors (temperature and pH), 
chemical factors such as total suspended solids (TSS), 
biochemical oxygen demand (BOD), total nitrogen (TN), 
total phosphorus (TP), chemical oxygen demand (COD), 
electrical conductivity (EC), manganese, iron, and anions 
(sulfates, chlorides, and nitrates).
Additionally, microbial factors like fecal coliforms (FC) 
and Escherichia coli (E. coli) were also examined. On-site 
temperature readings were taken using a thermometer, 
while pH and electrical conductivity (EC) measurements 
were performed immediately after sample collection 
with a pH meter and EC meter, respectively, following 
the procedures outlined by Motsara and Roy (2008). 
The concentrations of  calcium and magnesium were 
determined using titrimetric analysis based on the standard 
EDTA method (American Public Health Association, 
2020). Analysis of  heavy metals, such as nickel (Ni), 
cadmium (Cd), zinc (Zn), copper (Cu), and lead (Pb), was 
conducted at the Sustainable Laboratory in Akure, Nigeria. 
Levels of  sodium (Na) and potassium (K) were assessed 
using a flame photometer, while chloride content was 
quantified through titration with silver nitrate (AgNO3).

Figure 1: Raw Grey-water from Jadesola Akande Hostel 
to the Sedimentation tank at the Experimental Field

Figure 2: Constructed Wetland planted with Common 
reed at the Experimental Field



Pa
ge

 
10

https://journals.e-palli.com/home/index.php/ajec

Am. J. Environ. Clim. 4(2) 7-14, 2025

Figure 3: Grey-water Treatment Setup

Both biochemical oxygen demand (BOD) and chemical 
oxygen demand (COD) were measured using the standard 
Open Method at the same laboratory to determine 
the levels of  organic pollution. Total suspended solids 
(TSS) were assessed through the gravimetric method, 
specifically for “total suspended non-filterable solids,” in 
accordance with APHA guidelines (2005).

RESULTS AND DISCUSSION
To evaluate the suitability of  treated grey-water for 
irrigation, the following characteristics of  irrigation water 
in the study area were analyzed:

pH of  Treated Grey-water 
The pH analysis revealed values of  7.08, 6.10, and 8.06 for 
treated grey-water during the dry seasons of  2016, 2017, 
and 2018, respectively (Table 2). According to Food and 
Agriculture Organization (2003) guidelines, an effluent 
pH range of  6.5 to 9.0 is desirable for irrigation, while the 
Environmental Protection Agency (EPA, 2004) and the 
World Health Organization (WHO, 1989) recommend a 
pH range of  6.5 to 8.5. The temperature and pH values 
observed in this study align with findings from previous 
research in similar areas (Kayombo et al., 2000; Kaseva, 
2004). These ranges support high microbial activity, as 
they fall within the optimal pH range of  6.0 to 9.0 and a 
temperature range of  25°C to 35°C (Metcalf  and Eddy, 
2003). Variations in pH and temperature can be attributed 
to different weather conditions on sampling days (such as 
sunny or cloudy weather) and the composition and volume 
of  sewage released. The design of  the wetland system, 
which incorporates both plants and gravel, influences 
these parameters by reducing direct sunlight exposure to 
the grey-water as it passes through the wetland. The lower 
pH levels observed in treated grey-water compared to 
raw grey-water inflows may be attributed to the inability 
of  the plants to exude or absorb carbon dioxide during 
daylight hours, as both plants and microorganisms engage 
in photosynthetic activity (Kaseva, 2004; Kyambadde et 
al., 2004).

Salinity Hazard of  Treated Grey-water
The analysis of  treated grey-water indicated that Total 
Dissolved Solids (TDS) were 1152 mg/L, 1226 mg/L, 
and 1300 mg/L during the dry seasons of  2016, 2017, 
and 2018, respectively. Furthermore, the Electrical 
Conductivity (EC) values measured were 2.43 dS/m, 2.26 
dS/m, and 2.60 dS/m respectively for the same years 
(Table 2). Consequently, the treated grey-water presents a 
slight to moderate salinity issue for crops, as FAO (2003) 
suggests an acceptable EC range of  0 to 2.0 dS/m. 
Additionally, Pescod (1992) recommends a TDS range of  
450 to 2000 mg/L for wastewater used in irrigation. Since 
the EC of  the treated grey-water exceeds this range, it 
may lead to slight to moderate degradation of  the soil’s 
physical structure, potentially reducing plant growth, 
root and shoot lengths, and overall yield (Omami, 2005; 
Agarwai and Pandey, 2004). To mitigate salinity issues, 
applying additional freshwater beyond the plants’ needs 
can help leach salts from the root zone (Plaut et al., 2013).

Sodium (Na) Hazard of  Treated Grey-water
The concentrations of  sodium (Na) in treated grey-water 
were documented over three consecutive dry seasons, 
showing values of  41.20 ppm in 2016, 42.40 ppm in 2017, 
and 43.60 ppm in 2018. For the same years, raw grey-
water samples had significantly higher Na concentrations, 
recorded at 57.50 ppm, 60.30 ppm, and 63.10 ppm, 
respectively, as detailed in Tables 1 and 2. According to 
Pescod (1992), sodium levels in all analyzed water samples 
fell within acceptable ranges for irrigation purposes, 
as they remain sufficiently low to prevent negative 
impacts on soil structure or plant health. The treatment 
process effectively reduced sodium levels, aligning with 
irrigation suitability standards. This reduction in sodium 
concentration contributes to maintaining soil permeability 
and preventing potential sodium-induced issues, which 
can be beneficial in long-term agricultural applications.

Chloride Contents of  Treated Grey-water
Chloride concentrations are a key factor in evaluating the 



Pa
ge

 
11

https://journals.e-palli.com/home/index.php/ajec

Am. J. Environ. Clim. 4(2) 7-14, 2025

quality of  irrigation water because high levels of  chloride 
can be harmful to plants and also act as a measure of  
water salinity. In the treated grey-water samples, chloride 
concentrations measured were 18.82 mg/L, 19.43 mg/L, 
and 20.04 mg/L for the dry seasons of  2016, 2017, and 
2018, respectively. These values suggest that the treated 
grey-water is appropriate for use with salt-tolerant crops, 
which can withstand mild salinity without adverse effects 
on growth or yield. The relatively modest chloride levels 
observed in the treated grey-water samples may reflect 
the efficiency of  the treatment process in reducing 
salinity-related constituents. This reduction is crucial for 
minimizing potential negative impacts on plant health 
and soil structure over extended irrigation periods, as 
displayed in Table 2. The capacity to manage chloride 
concentration through effective grey-water treatment 
ensures that the water remains viable for agricultural use, 
supporting both crop growth and soil sustainability.

Microbial Parameters of  Treated Grey-water
The evaluation of  treated grey-water showed levels of  
Fecal Coliform (FC) bacteria measuring 390, 530, and 
460 CFU/100 ml for the dry seasons of  2016, 2017, 
and 2018, respectively. These results suggest a lower risk 
of  pathogen presence in the treated water, as detailed 
in Table 2. The observed decrease in FC levels can be 
attributed to the initial sedimentation phase, during which 
the grey-water was retained for several days. This retention 
period allows for natural purification processes to take 
place. Various mechanisms contribute to the reduction of  
bacterial populations, including sedimentation, chemical 
reactions, natural die-off, and the predation of  bacteria 

by organisms such as zooplankton, nematodes, lytic 
bacteria, and bacteriophages, as discussed by Kadlec and 
Knight (1996). Additionally, plants play a vital role in the 
wastewater treatment process, primarily through their 
physical contributions. Macrophytes help stabilize the 
surfaces of  treatment beds, enhance physical filtration 
capabilities, and create a substantial surface area that 
promotes microbial growth, thereby facilitating further 
purification (Brix, 2020). This multifaceted approach 
ensures the effective treatment of  greywater, reducing 
pathogens and improving overall water quality.

Chemical Parameters (COD, BOD and TSS) of  
Treated Grey-water
The results indicated that the treated grey-water is 
suitable for irrigation based on the BOD values of  23.00 
mg/L, 26.00 mg/L, and 24.50 mg/L, and COD values 
of  33.22 mg/L, 35.51 mg/L, and 37.80 mg/L for the dry 
seasons of  2016, 2017, and 2018, respectively (Table 2). 
These values fall within the FAO’s acceptable limits of  60 
mg/L for BOD and 200 mg/L for COD (Pescod, 1992). 
However, the TSS of  the treated grey-water were 89.00 
mg/L, 92.00 mg/L, and 95.00 mg/L for the same years, 
which exceed the FAO’s acceptable limit of  50 mg/L. 
This could potentially lead to soil plugging in irrigation 
systems. The relatively low BOD and COD levels in 
the treated grey-water were likely due to purification 
processes occurring in the sedimentation tank, and these 
findings are consistent with earlier studies by Bilha (2006) 
and Seswoya and Zainal (2010). The lower values in this 
study compared with other reports may be attributed to 
the reduced levels of  degradable organic matter entering 
the constructed wetland system, since most of  it may 

Table 1: Properties of  the Raw Greywater at the Experimental Site

Ye
ar

Te
m

p 
(°

C
)

pH C
O

D
 (m

g
/L

)

B
O

D
 

(m
g/

L)

T
SS

 
(m

g/
L)

E
C

 
(d

S/
m

)

N
O

3 
(m

g/
L)

SO
42 ˉ 

(m
g/

L)

T
D

S 
(m

g/
L)

FC
 

(C
FU

/1
00

 
m

l)

C
l ˉ

 
(m

g/
L)

2016 27.20 7.46 415.77 274.35 109.00 3.72 24.60 2542.50 1995.00 2570 17.02

2017 28.10 6.26 415.77 286.40 107.00 4.02 23.40 2551.30 2001.00 2440 15.53

2018 29.00 8.66 406.44 298.45 111.00 4.32 25.80 2560.10 1998.00     2700 18.51
Standard 
(Pesco, 
1992)

Nill 6 - 
9

200 60 50 0.7 – 3 50 2000 450 – 2000 1000 500

Table 2: Properties of  the Treated Greywater at the Experimental Site

Ye
ar

Te
m

p 
(°

C
)

pH C
O

D
 (m

g
/L

)

B
O

D
 (m

g
/L

)

T
SS

 (m
g

/L
)

E
C

 (d
S

/m
)

N
O

3 (
m

g
/L

)

SO
42 ˉ 

(m
g

/L
)

T
D

S 
(m

g/
L)

FC
 

(C
FU

/1
0

0 
m

l)

C
l ˉ

 
(m

g/
L)

2016 27.80 7.08 33.22 23.00 89.00 2.43 11.40 1546.50 1152.00 390 18.82

2017 28.10 6.10 35.51 26.00 92.00 2.26 12.40 1563.70 1226.00 530 19.43

2018 29.40 8.06 37.80 24.50 95.00 2.60 13.40 1580.90 1300.00 460 20.04
Standard 
(Pesco, 
1992)

Nill 6 - 9 200 60 50 0.7 – 3 50 2000 450 – 
2000

1000 500



Pa
ge

 
12

https://journals.e-palli.com/home/index.php/ajec

Am. J. Environ. Clim. 4(2) 7-14, 2025

have been removed during the sedimentation process.
Heavy Metals of  Irrigation Water
The heavy metals analyzed included cadmium, copper, 
lead, zinc, nickel, and manganese (FAO, 1992). The results 
showed that the concentrations of  heavy metals in the 
treated grey-water were within the acceptable limits set by 
WHO, indicating they are unlikely to pose risks to soil or 
crops (Table 4). The removal efficiencies for manganese 
(Mn) were 88%, 88.71%, and 72.72% for the dry seasons 
of  2016, 2017 and 2018, respectively. For iron (Fe), the 
removal efficiency was 85.71% across all three seasons. 
Lead (Pb) showed a removal efficiency of  98% for the 
three seasons, while nickel (Ni) achieved 100% removal 
efficiency throughout. The removal rates for zinc (Zn) 
were 3.90%, 14.45%, and 14.58% for 2016, 2017, and 2018, 

respectively, and for copper (Cu), the efficiencies were 
58.33%, 79.17%, and 80.56% during the same periods. 
The removal efficiencies observed align with earlier 
studies conducted by Nakwanit et al. (2011), Akinbile et 
al. (2012), Tuheteru et al. (2016), Pongthornpruek (2017), 
Thathong et al. (2019), Prasetya et al. (2020), Ismail et 
al. (2024), and Zubairet al. (2021). Exceptional removal 
of  heavy metals has been noted by Nguyen et al. (2021) 
and Ismail et al. (2024), which they attributed to the use 
of  added rhizobacteria and adsorbents in constructed 
wetland systems. Overall, heavy metals were primarily 
eliminated through rhizofiltration, where the roots of  the 
plants in the water absorb metals. Once absorbed through 
the root membranes, these metals can either be retained 
in the roots or transported to other parts of  the plant for 

Table 3: Concentrations of  Heavy Metals in Raw Grey-water used in the Experiment

Year Mn (ppm) Fe (ppm) Pb (ppm) Ni (ppm) Cd (ppm) Zn (ppm) Cu (ppm)
2016 0.100 0.014 0.050 0.002 Nill 0.154 0.060

2017 0.105 0.014 0.050 0.002 Nill 0.173 0.120

2018 0.110 0.014 0.050 0.002 Nill 0.192 0.180

WHO Standard 
(1985)

0.400 0.300 0.010 0.020 0.003 3.000 2.000

Table 4: Concentrations of  Heavy Metals in Treated Grey-water used in the Experiment

Year Mn (ppm) Fe (ppm) Pb (ppm) Ni (ppm) Cd (ppm) Zn (ppm) Cu (ppm)
2016 0.012 0.002 0.001 Nill Nill 0.148 0.025

2017 0.021 0.002 0.001 Nill Nill 0.156 0.030

2018 0.030 0.002 0.001 Nill Nill 0.164 0.035

WHO Standard 
(1985)

0.400 0.300 0.010 0.020 0.003 3.000 2.000

tissue localization (Prasetya et al., 2020).
CONCLUSION
This study set out to examine the suitability of  grey-
water treated with common reed in constructed wetlands 
for irrigation purposes in Akure, Nigeria. Through 
detailed analyses, the findings revealed that the treatment 
process significantly improved the quality of  the grey-
water. Specifically, the treatment led to reductions in key 
physico-chemical and microbial parameters, reflecting a 
notable improvement in water quality. Additionally, the 
constructed wetland system, which utilized common 
reed, was effective in reducing concentrations of  heavy 
metals, highlighting its role in enhancing the overall 
safety and usability of  the treated water. The removal 
efficiencies for various heavy metals, such as manganese, 
iron, and lead, were particularly impressive, further 
supporting the treatment’s effectiveness. Based on the 
results, it can be concluded that the treated grey-water 
met the required standards for irrigation water reuse, with 
all analyzed parameters falling within acceptable limits set 
by regulatory bodies. This suggests that common reed-
treated grey-water can be a viable alternative for irrigation 
in agricultural settings, contributing to sustainable water 
management practices in areas like Akure. The findings 

underscore the potential of  using constructed wetlands 
with macrophytes like common reed not only for 
improving grey-water quality but also for promoting 
environmentally sound irrigation practices. Consequently, 
the treated grey-water from this system is deemed safe 
and suitable for agricultural use, aligning with guidelines 
for wastewater reuse in irrigation.

REFERENCES
Agarwal, S., & Pandey, V. (2004). Antioxidant enzyme 

response to NaCl stress in Cassia angustifolia. Biologia 
Plantarum, 48(4), 555-560.

Aiyelokun, O. O., Olanipekun, A. A., Idusuyi, D. U., 
Bayode, O., & Saka, Q. O. (2024a). Design and 
optimization of  cascade aerator using AI-Integrated 
software for Bells university of  technology’s water 
treatment Plant. European Journal of  Applied Science and 
Engineering Technology, 2(5), 118-129.

Aiyelokun, O. O., Olanipekun, A. A., & Agbede, O. A. 
(2024b). Design and optimization of  parshall flume 
and flash mixer using iNODE software for water 
treatment plant. Adeleke University Journal of  Engineering 
and Technology, 7(2), 25–37.

Akhtar, A. B. T., Yasar, A., Ali, R., & Irfan, R. (2017). 



Pa
ge

 
13

https://journals.e-palli.com/home/index.php/ajec

Am. J. Environ. Clim. 4(2) 7-14, 2025

Phytoremediation using aquatic macrophytes. 
Phytoremediation, +Springer, Cham: 259–276.

Akinbile, C. O., Yusoff, M. S., & Zuki, A. A. (2012). 
Landfill leachate treatment using sub-surface flow 
constructed wetland by Cyperus haspan. Waste 
management, 32(7), 1387-1393.

APHA. (2020). Standard methods for the examination of  water 
and waste water (20th ed., pp. 23–31). Washington, D.C., 
American Public and Health Association.

Beauclair, N. (2021). Passive treatment of  acid mine drainage 
using an integration of   neutralization and a constructed 
aerobic wetland. Doctoral dissertation, College of  
Sciences Engineering and Technology, University of  
South Africa.

Bilha, E., (2006). Biochemical oxygen demand reaction kinetics 
and mass transfer in horizontal subsurface flow constructed 
wetland. MSc Dissertation, University of  Dar  es 
Salaam, Tanzania.

Brix, H. (1993). Wastewater treatment in constructed 
wetland system: design, removal processes and 
treatment performance. In; Moshiri, G. A. (Ed). 
Constructed Wetland for Water Quality Improvement. CRC 
press Inc.

Brix, H. (2020). Wastewater treatment in constructed 
wetlands: system design, removal processes, and 
treatment performance. In Constructed wetlands for water 
quality improvement. CRC Press.

Dan, A., Yang, Y., Dai, Y. N., Chen, C. X., Wang, S. Y., 
& Tao, R. (2013). Removal and factors influencing 
removal of  sulfonamides and trimethoprim from 
domestic sewage in  constructed wetlands. Bioresource 
technology, 146, 363-370.

Dordio, A., Ferro, R., Teixeira, D., Palace, A. J., Pinto, A. P., 
& Dias, C. M. (2011). Study on  the use of  Typha 
spp. for the phytotreatment of  water contaminated 
with  ibuprofen. International Journal of  Environmental 
and Analytical Chemistry, 91(7-8), 654-667.

EPA. (2004). Manual Guidelines for Water Reuse, 
EPA/625/R-92/004, USA.

FAO. 2003. Hazard analysis and critical control point 
(haccp) system and guidelines for its application. 
In Recommended International Code of  Practice: General 
Principles of  Food Hygiene (CAC/RCP 1-1969, rev. 
4-2003), 21−31. 

Gholipour, A., Zahabi, H., & Stefanakis, A.I., (2020). A 
novel pilot and full scale constructed wetland study 
for glass industry wastewater treatment. Chemosphere, 
247, 125966.

Ghosh, A., & Chakraborty, T. R. (2025). Use of  water 
hyacinth for adaptation to climate change in 
Bangladesh. American Journal of  Environment and 
Climate, 4(1), 113-118.

Greenaway, M., & Woolley, A. (2001). Changes in plant 
biomass and nutrient removal over 3 years in a 
constructed wetland in Cairns, Australia. Water Science 
and Technology, 44(11-12), 303-310.

Ha, N. T. H., Sakakibara, M., & Sano, S. (2011). 
Accumulation of  indium and other heavy  metals by 

Eleocharis acicularis: an option for phytoremediation 
and  phytomining. Bioresource technology, 102(3), 2228-
2234.

Ismail, U. M., Vohra, M. S., & Onaizi, S. A. (2024). 
Adsorptive removal of  heavy metals from aqueous 
solutions: Progress of  adsorbents development and 
their  effectiveness. Environmental Research, 1185-1192.

Kadlec, R. H., & Knight, R. L. (1996). Treatment wetlands. 
Lewis Publishers, Boca Raton, FL.

Kaseva, M. (2004). Performance of  subsurface flow 
constructed wetland in polishing pre-treated water: A 
tropical case study. J. Water Research. 38, 681-687.

Kayombo, S., Mbwette, T. S. A., Mayo, A. W., Katima, J. 
H. Y., & Jorgensen, S. E. (2000).  Modelling diurnal 
variation of  dissolved oxygen in waste stabilization 
ponds. Ecological Modelling, 127(1), 21-31.

Ko, Y. G. (2024). Hybrid method integrating adsorption 
and chemical precipitation of  heavy metal ions on 
polymeric fiber surfaces for highly efficient water 
purification. Chemosphere, 142909.

Kumar, J. I. N., H. Soni, Kumar, R. N., & Bhatt, I. 
(2008). Macrophytes in phytoremediation of  heavy 
metal contaminated water and sediments in Pariyej 
community reserve, Gujarat, India.Turkish Journal of  
Fisheries and Aquatic Sciences, 8,193–200.

Kyambadde, J., Kansiime, F., Gumaelius, L., & Dalhammar, 
G. (2004). A comparative study of  Cyperus papyrus 
and Miscanthidium violaceum-based constructed 
wetlands for  wastewater treatment in a tropical 
climate. Water Research, 38(2), 475-485.

Li, Y., Lian, J., Wu, B., Zou, H. & Tan, S. K. (2020). 
Phytoremediation of  pharmaceutical contaminated 
wastewater: Insights into rhizobacterial dynamics 
related to pollutant degradation mechanisms during 
plant life cycle. Chemosphere, 253, 126681.

Liu, Y., Naidu, R., & Ming, H. (2011). Red mud as an 
amendment for pollutants in solid and liquid phases. 
Geoderma, 163(1-2), 1-12.

Liu, D., Wang, P., Wei, G., Dong, W., & Hui, F. (2013). 
Removal of  algal blooms from freshwater by 
the coagulation–magnetic separation method. 
Environmental Science and  Pollution Research, 20, 60-65.

Metcalf, & Eddy. (2003). Wastewater engineering: treatment 
and reuse (4th ed.).  McGraw-Hill, New York.

Nakwanit, S., Visoottiviseth, P., Khokiattiwong, S., & 
Sangchoom, W. (2011). Management of  arsenic-
accumulated waste from constructed wetland 
treatment of  mountain tap-water. Journal of  Hazardous 
Materials, 185(2-3), 1081-1085.

Napaldet, J. T., & Buot Jr, I. E. (2019). Treatment of  
Balili River in Benguet, Philippines with constructed 
wetland planted with dominant local macrophytes. 
International Journal of  Phytoremediation, 21(14), 1463-
1473.

Nguyen, T. H., Won, S., Ha, M. G., Nguyen, D. D., & 
Kang, H. Y. (2021). Bioleaching for environmental 
remediation of  toxic metals and metalloids: A review 
on soils, sediments, and mine tailings. Chemosphere, 



Pa
ge

 
14

https://journals.e-palli.com/home/index.php/ajec

Am. J. Environ. Clim. 4(2) 7-14, 2025

282, 131108.
Oladejo, O.S. (2014). Fundamentals of  environmental 

engineering. Handbook of  Environmental Engineering (1st 
ed.). Olanrewaju Publishers, Ogbomoso, Nigeria.

Oladejo, O. S., & Olanipekun, A. A. (2018). Phyto-
remediation of  municipal run-off  using typha 
orientalis and sorghum arundinaceum in sub-surface 
constructed wetland  system. International Research 
Journal of  Advanced Engineering and Science, 3(1), 211–
215.

Olanipekun, A. A., & Idusuyi, D. U. (2023). Design 
and construction of  bio-sand filtration system for 
treatment of  influent obtained from a well and 
stream. International Journal of  Scientific and Engineering 
Research, 1(1), 1–15.

Olanipekun, A. A., Idusuyi, D. U., Aiyelokun, O. O., 
Alao, F., Bayode, O., Saka, Q. O., & Adeyi, A. S. 
(2024). Effects of  anthropogenic activities on the 
water quality parameters of  Iju stream, Ota, Ogun 
State, Nigeria. European Journal of  Science, Innovation and 
Technology, 4(5), 316-325.

Omami, E. N. (2005). Response of  Amaranth to Salinity Stress. 
PhD Thesis, University of  Pretoria, South Africa.

Pescod, M. B. (1992). Wastewater treatment and use in 
agriculture. FAO Irrig. Drain. Paper. 4, Rome, Italy.

Pongthornpruek, S. (2017). Swine farm wastewater 
treatment by constructed wetland planted with vetiver 
grass. Environment & Natural Resources Journal, 15(2), 
13-20.

Plaut, Z., Edelstein, M., & Ben-Hur, M. (2013). 
Overcoming salinity barriers to crop production 
using traditional methods. Critical Reviews in Plant 
Sciences, 32(4), 250-291.

Prasetya, A., Prihutami, P., Warisaura, A. D., Fahrurrozi, 
M., & Petrus, H. T. B. M. (2020).  Characteristic of  Hg 
removal using zeolite adsorption and Echinodorus 
palaefolius phytoremediation in subsurface flow 
constructed wetland (SSF-CW) model. Journal of  
Environmental Chemical Engineering, 8(3), 103781.

Reed, S. C. (1993). Subsurface flow constructed wetlands for 
wastewater treatment. A Technology Assessment, United 
States Environmental Protection Authority Agency, 
832-R-P3-008.

Reed, S. C., Middlebrook, E. J., & Crities, R. W. (1987). 
Natural system for waste management and treatment. 
McGraw - Hill, New York.

Saeed, T., & Sun, G. (2013). A lab-scale study of  
constructed wetlands with sugarcane bagasse and 
sand media for the treatment of  textile wastewater. 
Bioresource technology, 128, 438-447.

Said, N. S. M., Abdullah, S. R. S., Hasan, H. A., Othman, 
A. R., & Ismail, N. I. (2021). Endurance of  Phragmites 
karka in removing colour and suspended solids from 

industrial coffee processing effluents in a continuous 
reed bed system. Journal of  Water Process Engineering, 
40, 101832.

Seswoya, R., & Zainal, M. Y. (2010). Subsurface-flow 
constructed wetland: proposed design area for high 
strength effluent domestic wastewater. International 
Conference on Science and Technology Application in Industry 
& Education, 1-6.

Sijimol, M. R., & Joseph, S. (2021). Constructed wetland 
systems for greywater treatment and reuse: A review. 
International Journal of  Energy and Water Resources, 5(3), 
357–369.

Thathong, V., Tantamsapya, N., Yossapol, C., Liao, C. H., 
Wirojanagud, W., & Padungthon, S. (2019). Role of  
Colocasia esculenta L. schott in arsenic removal by a 
pilot-scale constructed wetland filled with laterite soil. 
Heliyon, 5(2), e01233.

Tuheteru, F. D., Kusmana, C., Mansur, I., Iskandar, I., 
& Tuheteru, E. J. (2016). Potential of  lonkida (Nauclea 
orientalis L.) for phytoremediation of  acid mined drainage at 
PT. Bukit Asam Tbk. (Persero), Indonesia.

Vymazal, J. (2011). Constructed wetlands for wastewater 
treatment: Five decades of  experience. Environ. Sci. 
Technol. 45, 61-69.

Vymazal, J. (2013). Emergent plants used in free water 
surface constructed wetlands: A review. Ecological 
Engineering, 61, 582-592.

World Health Organization. (1989). Health guidelines for the 
use of  wastewater in agriculture and aquaculture: report of  a 
WHO scientific group [meeting held in Geneva from 18 
to 23 November 1987. World Health Organization.

WHO. (2006). Guideline for the safe use of  wastewater, excreta 
and greywater, Geneva.

Wu, W., Yang, Y., Zhou, H., Ye, T., Huang, Z., Liu, R., 
& Kuang, Y. (2013). Highly efficient removal of  Cu 
(II) from aqueous solution by using graphene oxide. 
Water, Air, & Soil Pollution, 224, 1-8.

Xu, D., Lee, L. Y., Lim, F. Y., Lyu, Z., Zhu, H., Ong, S. L., 
& Hu, J. (2020). Water treatment residual: A critical 
review of  its applications on pollutant removal from 
stormwater  runoff  and future perspectives. Journal 
of  environmental management, 259, 109649.

Yadav, A. K., Abbassi, R., Kumar, N., Satya, S., 
Sreekrishnan, T. R., & Mishra, B. K. (2012). The 
removal of  heavy metals in wetland microcosms: 
Effects of  bed depth, plant species, and metal 
mobility. Chemical Engineering Journal, 211, 501-507.

Zubair, M., Ihsanullah, I., Aziz, H. A., Ahmad, M. A., 
& Al-Harthi, M. A. (2021). Sustainable wastewater 
treatment by biochar/layered double hydroxide 
composites: Progress,  challenges, and outlook. 
Bioresource technology, 319, 124128.


