ArticlePDF Available

Abstract and Figures

Sewage generated in Ghana is commonly discharged into the environment without any form of treatment to reduce the degree of contamination and mitigate potential public health and environmental issues. Although some attempts have been made in some parts of Ghana to utilize the waste stabilization pond (WSP) system to treat domestic sewage, the ponds often fail to achieve their purpose due to lack of basic maintenance and supervision. To assess the utility of the WSP system for treating sewage, wastewater samples were collected from the raw sewage, anaerobic, facultative and maturation ponds of WSPs at Obuasi in Ghana, and analyzed for physicochemical and microbiological contaminants. The results show that the final pond effluent meets recommended microbiological and chemical quality guidelines. The waste stabilization pond system demonstrates high removal efficiencies of wastewater contaminants. The biochemical oxygen demand, total suspended solids, nitrate and faecal coliforms reduction efficiencies of 97.3%, 97.6%, 83.3% and 99.94% respectively are highly significant, and compare well with reported removal efficiencies in the literature. Additionally, the ponds have high reduction efficiencies for heavy metals and pathogenic microorganisms. The wastewater treatment system complies with standard wastewater management practices, and provides a useful method for treating and disposing wastewater in Ghana.
Content may be subject to copyright.
JENRM, Vol. 3, No. 1, 7-14, 2016
Research Article
Sewage Treatment by Waste Stabilization Pond
Systems
Kenneth J. Bansah *, Raymond S. Suglo **
Abstract
Sewage generated in Ghana is commonly discharged into the environment without any form of treatment to reduce the degree of
contamination and mitigate potential public health and environmental issues. Although some attempts have been made in some
parts of Ghana to utilize the waste stabilization pond (WSP) system to treat domestic sewage, the ponds often fail to achieve
their purpose due to lack of basic maintenance and supervision. To assess the utility of the WSP system for treating sewage,
wastewater samples were collected from the raw sewage, anaerobic, facultative and maturation ponds of WSPs at Obuasi in
Ghana, and analyzed for physicochemical and microbiological contaminants. The results show that the final pond effluent meets
recommended microbiological and chemical quality guidelines. The waste stabilization pond system demonstrates high removal
efficiencies of wastewater contaminants. The biochemical oxygen demand, total suspended solids, nitrate and faecal coliforms
reduction efficiencies of 97.3%, 97.6%, 83.3% and 99.94% respectively are highly significant, and compare well with reported
removal efficiencies in the literature. Additionally, the ponds have high reduction efficiencies for heavy metals and pathogenic
microorganisms. The wastewater treatment system complies with standard wastewater management practices, and provides a
useful method for treating and disposing wastewater in Ghana.
Keywords
Wastewater—Pathogens—Waste Stabilization Ponds—Faecal Coliform—Sewage
*Department of Mining and Nuclear Engineering, Missouri University of Science and Technology, Rolla-Missouri, USA, Email:
kjbt3c@mst.edu; kjbansah@yahoo.com
**Department of Mining and Geological Engineering, Botswana International University of Science and Technology, Botswana, Email:
rsuglo@yahoo.ca
Contents
1 Introduction 7
2 Location, Relief and Climate of Obuasi 8
3 Waste Stabilization System 8
4 Methods 105
5 Results and Discussion 10
6 Conclusions and Recommendation 12
References 12
1. Introduction
Waste stabilization ponds (WSPs) utilize shallow basins10
for wastewater treatment through natural disinfection
mechanisms by integrating the activity of phototrophic,
autotrophic and heterotrophic microorganisms [
1
]. Ef-
fectively treating wastewater effluents can efficiently con-
tribute to water conservation, expansion of irrigated agri-
15
culture, environmental and public health protection [2].
Although WSPs are most commonly used for treating
domestic wastewaters, they have been recommended by
the World Health Organization (WHO) for the treatment
of agro-industrial wastes for reuse in agriculture and
20
aquaculture due to their effective removal of excreted
pathogens and helminth eggs [
3
]. Stabilizing sewage by
utilizing WSP is considered an appropriate technique for
the treatment and removal of pathogenic microorganisms
from wastewater in tropical and subtropical regions of
25
the world.
The ponds require little energy (only sunlight) and
no disinfectants [
4
], while playing an important role in
the removal of contaminants such as crude oil and heavy
metals. These low energy consuming ecosystems that use
30
natural processes in contrast with complex high mainte-
nance treatment systems (such as trickling filters, acti-
vated sludge treatment, rotary biological contactors, etc.)
have become well established as methods for wastewater
treatment in tropical climates [
5
]. The treatment tech-
35
nique uses minimal operational and maintenance input
to produce an effluent that meets the recommended mi-
crobiological and physicochemical quality guidelines [6].
Additionally, it requires daily minimum supervision for
its operation, by simply cleaning the outlets and inlet
40
channels.
WSP system generally consists of a series of ponds
involving anaerobic, facultative and maturation ponds
[
5
,
7
,
8
]. Anaerobic and facultative ponds are respec-
tively used for primary treatment and secondary treat-
45
ment. They are both for the removal of biochemical
oxygen demand (BOD), Vibrio cholerae and helminth
eggs. The maturation ponds are used for tertiary treat-
Sewage Treatment by Waste Stabilization Pond Systems — 8/13
ment of wastewater effluents and responsible for the re-
moval of faecal viruses (e.g. rotavirus, astrovirus and
50
norovirus), faecal bacteria (e.g. Salmonella spp., Shigella
spp., pathogenic strains of Escherichia coli) and, nitrogen
and phosphorus nutrients [9].
The relative advantages of WSPs compared to other
conventional wastewater treatment systems (such as ro-
55
tary biological contactors, activated sludge treatment,
trickling filters, aerated lagoons, biological filters and
reed-bed systems) in relation to effluent standards with
respect to algae removal, input of external energy, nutri-
ent removal and relative costs include simplicity, low cost,
60
low maintenance, low energy consumption, robustness,
and environmental sustainability [10].
WSPs are particularly well suited for tropical and
subtropical countries such as Ghana. Stabilization ponds
are widely used for treatment of municipal wastewater in
65
many countries with ample sunshine such as Colombia, El
Salvador, Guatemala, Honduras, Israel, Jordan, Morocco,
Nicaragua, Tunisia and Uganda [
11
]. They are typically
used in smaller towns where land availability and cost is
less of a constraint. In some cities (e.g. Amman in Jordan
70
and Adelaide in Australia), larger stabilization ponds
have been replaced in the early 2000s by activated sludge
wastewater treatment plants. Due to the temperature and
lengthy duration of sunlight which are key factors that
enhance the performance process and effectiveness of the
75
treatment system, tropical and subtropical countries offer
excellent opportunity for high efficiency and satisfactory
performance [12].
According to [
13
], the commonest secondary treat-
ment technologies adopted for domestic sewage treatment
80
in Ghana are trickling filters, activated sludge and waste
stabilization ponds. WSPs installed in some towns and
communities such as Akuse, Akosombo and Kumasi are
reported to perform remarkably well [
13
,
14
]. However,
the management of domestic wastewater in Ghana still
85
remains a major problem to the local and national gov-
ernments.
To complement the efforts by government in solving
the challenges posed by sewage, six WSPs have been built
by AngloGold Ashanti (Obuasi) mine for the collection
90
and treatment of sewage to reduce the effect of certain
water contaminants on the environment and protect pub-
lic health. The wastewater in these ponds is treated to
ensure that the levels of certain contaminants are brought
below acceptable limits before discharging the effluents
95
into the natural environment. To avoid polluting soils,
receiving waters and endangering human health, flora,
fauna and aquatic lives downstream from the points of
discharge, it is necessary to monitor some water quality
parameters in the treated domestic wastewater before it is
100
discharged. This also provides a means for evaluating the
performance of the treatment mechanism and makes data
available for trend analysis and regulation evaluation.
2. Location, Relief and Climate of Obuasi
Obuasi is located in the Obuasi Municipal Assembly of
105
the Ashanti Region of Ghana. The town is located 64 km
south-east of Kumasi, the regional capital and 175 km
north-west of Accra, the capital of Ghana. It has easy
access to most parts of the country both by road and by
railway. By railway, it is 72 km south of Kumasi, 192
110
km north of Takoradi habour and 330 km north-west of
Accra.
Obuasi is situated in the tropical rainforest zone of
Ghana. It has a long rainy season, which spans from
March to December, followed by a brief dry season with
115
sporadic rainfall from December to February. The highest
rainfall occurs between May and July averaging 77.3 mm
while the least occurs in December with an annual average
rainfall of 39.1 mm. The annual average temperature is
28
o
C. The area has thick vegetation and, where the relief
120
is very high, there are usually shrubs [
15
]. Fig. 1 shows
the location of the study area.
3. Waste Stabilization System
Waste stabilization systems comprise a single series of
anaerobic, facultative and maturation ponds, or several
125
such series in parallel. Anaerobic and facultative ponds
are designed for removal of biochemical oxygen demand
(BOD) and maturation ponds for pathogen removal. How-
ever, some BOD removal also occurs in maturation ponds
and some pathogen removal in anaerobic and facultative
130
ponds [
7
]. Anaerobic and facultative ponds only are re-
quired when the treated wastewater is to be used for
restricted crop irrigation and fish pond fertilization, and
a relatively weak wastewater (up to 150 mg BOD/l) is to
be treated prior to surface water discharge. Maturation
135
ponds are required only when the treated wastewater is
to be used for unrestricted irrigation and when stronger
wastewaters (BOD > 150 mg/l) are to be treated prior
to surface water discharge [4, 12].
Usage of waste stabilization ponds for treatment of
140
sewage wastewaters can be found in over 50 countries
with very different climatic conditions. A great number
of these ponds can be found in Asia, Latin America and
Africa [
16
]. The common treatment technologies adopted
for domestic sewage treatments are trickling filters, acti-
145
vated sludge and waste stabilization ponds. [
17
] describes
the advantages of the WSP system over other treatment
systems including package plant, activated sludge, ex-
tended aeration activated sludge, biological ditch and
aerated lagoon. The WSP system outperforms the other
150
systems by its ability to remove BOD, faecal coliform,
helminth, and virus, the mode and cost of construction,
mode of operation, cost of maintenance, energy demand
and cost of sludge removal. The main limitations of WSPs
are that they require large areas of operation and are very
155
inefficient in the removal of suspended solids.
Sewage Treatment by Waste Stabilization Pond Systems — 9/13
Figure 1. Study Area
Under the tropical conditions in Ghana, the Waste
Stabilization Ponds (WSPs) have been found to be more
suitable and appropriate compared to conventional treat-
ment systems because of the ease of operation and mainte-
160
nance and the high level of treatment efficiencies they are
able to achieve [
14
]. Fig. 2 illustrates a typical scheme of
WSP.
Figure 2. Typical Scheme of a Waste Stabilization
System: Anaerobic, Facultative and Maturation Ponds
in Series (source: [18])
Fig. 3 is a schematic diagram of the WSP at Obuasi
[
19
]. These ponds consist of two anaerobic, four secondary
165
facultative, and two maturation ponds. The raw sewage
with high organic loading (compared to the other ponds)
is discharged into a small receptacle lined with sieves to
prevent large solids from entering the anaerobic ponds.
The anaerobic ponds are about 4 to 5 m deep. Their
170
primary function is BOD removal. In anaerobic ponds
sludge is deposited on the bottom and anaerobic bacteria
break down the organic matter by anaerobic digestion,
releasing methane and carbon dioxide. Viruses, bacteria,
helminth, Ascaris eggs and other pathogens can also be
175
inactivated by sedimentation when associated with solids.
Figure 3.
Schematic Diagram of the Waste Stabilization
Ponds at Obuasi
Nitrogen, phosphorus and potassium can also be reduced
by sludge formation and the release of ammonia into
the air [
20
]. Anaerobic ponds help to settle undigested
material and non-degradable solids as bottom sludge,
180
dissolve organic material and break down biodegradable
organic material.
The facultative ponds, which are 1 to 2 m deep, receive
settled wastewater from the anaerobic ponds. They are
also designed for BOD removal on the basis of a relatively
185
low surface loading (100 to 400 kg BOD/ha day) to per-
mit the development of a healthy algal population as the
oxygen for BOD removal by the pond bacteria is mostly
generated by algal photosynthesis [
5
]. The algae grow
using sunlight and produce oxygen in excess to their own
190
requirements. The excess oxygen is used by bacteria to
further break down organic matter via aerobic digestion
transforming the organic pollutants into carbon dioxide.
In addition to the aerobic and anaerobic digestion of BOD
in the facultative ponds "sewage BOD" is converted into
195
"algal BOD" [
5
]. As a complete process, the facultative
pond serves to further treat wastewater through sedimen-
tation and aerobic oxidation of organic material, reduce
odor, reduce some disease-causing microorganisms if pH
rises and store residues as bottom sludge [20]. 200
The maturation ponds (which are 1 to 1.5 m deep)
receive the effluent from the facultative ponds. The size
and the number of maturation ponds depend mainly on
the required bacteriological quality of the final effluent.
The primary function of maturation ponds is the removal
205
of excreted pathogens. Pathogens die off due to the high
temperature, high pH or radiation of the sun leading
Sewage Treatment by Waste Stabilization Pond Systems — 10/13
to solar disinfection. Virus removal occurs by adsorp-
tion onto settleable solids and consequent sedimentation
[
20
]. Maturation ponds achieve only a small removal of
210
BOD, but their contribution to nutrient (nitrogen and
phosphorus) removal can also be significant [5].
4. Methods
Samples were taken from the raw sewage and from the
effluents of Ponds 1 to 6. The American Public Health As-
215
sociation standard methods for the examination of water
and wastewater [
21
] were followed. The physicochemical
and microbiological parameters of WSP samples were
analyzed. Wastewater quality parameters analyzed in-
cluded total suspended solids (TSS), total dissolved solids
220
(TDS), pH, biological oxygen demand (BOD), nitrate,
total coliforms, faecal coliforms, Escherichia coli (E. coli),
oil and grease, dissolved oxygen, conductivity, colour,
lead (Pb), iron (Fe), copper (Cu), arsenic (As), zinc (Zn)
and chloride (Cl
). The quality of the final pond ef-
225
fluent was compared with recommended microbiological
and physicochemical quality guidelines (typically adapted
from the World Health Organization, U. S. Environmen-
tal Protection Agency, and the World Bank Group) by
the Environmental Protection Agency of Ghana (EPA)
230
to determine conformance. Additionally, the reduction
efficiencies of the various parameters were calculated by
using equation 1.
η=CrCf
Cr
×100 (1)
Where:
η
is removal or reduction efficiency in %,
Cr
is the concentration in the raw sewage,
Cf
is the
235
concentration in the final pond effluent.
5. Results and Discussion
The discharge of effluents with high TSS concentrations
can cause sludge depositions and anaerobic conditions in
the receiving water body. The TSS concentration of the
240
raw sewage is 1260 mg/l and that of the final effluent is 30
mg/l, giving a reduction efficiency of 97.6%. Fig. 4 shows
the TSS content of the effluents from the pond system.
The final effluent of the WSP system compares well with
recommended guidelines. The high TSS concentrations of
245
the effluents from the anaerobic and facultative ponds can
be attributed to the high TSS levels of the raw sewage.
The TSS removals in Ponds 1 to 5 support the findings of
Arthur [
17
], that the ability of WSP systems to remove
TSS is poor. However, it must be noted that the TSS
250
concentrations of the pond effluents decrease along the
treatment series as expected, and that the overall high
reduction efficiency achieved is in contrast with Arthur
[
17
]. The high TSS reduction efficiency demonstrates that
the WSP systems at Obuasi are efficient in reducing TSS.
255
Effluents with high concentrations of nitrates can
cause unwanted phytoplankton growth in the receiving
water bodies. According to Metcalf and Eddy [
22
], ni-
trate is typically absent in domestic sewage. The nitrate
concentration of the raw sewage is 2.39 mg/l while that
260
of the final effluent is 0.4 mg/l. The nitrate concentration
of the final effluent is acceptable as it is far less than
the guideline value of 50 mg/l. The nitrate removal ef-
ficiency of 83.3% achieved by the treatment ponds can
be described as appreciable. Fig. 5 shows the nitrate
265
concentrations of the effluents. The results show that
the nitrate levels in all the ponds are far lower than the
recommended guideline value.
When effluents with high concentrations of BOD are
discharged into the natural drains, they can cause deple-
270
tion of natural oxygen resources which may lead to septic
conditions. The BOD of the raw sewage is 280 mg/l and
that of the final pond effluent is 7.6 mg/l. The average
BOD removal efficiency of the ponds is calculated to be
97.3%. Fig. 6 shows the BOD levels in the effluents. A
275
study by Gloyna [
23
] indicates that it is uncommon to
obtain better than 90% BOD removal in waste stabiliza-
tion. The findings in this research suggest that the WSP
systems at Obuasi are very effective in the removal of
BOD. 280
The faecal coliforms level of the raw sewage is 65000
counts/100 ml while that of the final pond effluent is
40 counts/100 ml. The average faecal coliforms removal
efficiency is determined to be 99.94% which is signifi-
cant. Waste stabilization ponds usually give such high
285
micro-organism removal efficiency. Effluents with high
concentrations of faecal coliforms have high potential of
endangering public health. The concentration of the fae-
cal coliforms of the final effluent is very low compared to
the recommended guideline value of 1000 counts/100 ml
290
(see Fig. 7). This indicates that the final pond effluent
can be discharged into the natural environment without
posing threat to humans and the ecosystem in general.
Other wastewater parameters (pH, conductivity, TDS,
oil and grease, As, Fe, Cu, Pb, Zn, Cl
, total coliforms,
295
E. coli, colour and DO) of the final pond effluent compare
well with their respective recommended levels. The raw
sewage contains small concentrations of metals which can
be attributed to the relatively “normal” pH level. While
the metal concentrations of the final pond effluent remain
300
low and meet regulatory requirements, the pH of the
maturation ponds are higher than that of the anaerobic
and facultative ponds. It is common to find variations
in pH in WSP systems. Maturation ponds usually have
high pH which aid in the pathogen die-off mechanism.
305
Kayombo et al [
24
] also report diurnal pH changes in WSP,
and indicate that increase in pH up to 11 is common in
WSPs, with highest pH levels usually reached during the
late afternoon.
It is also demonstrated that the ponds can be effective
310
Sewage Treatment by Waste Stabilization Pond Systems — 11/13
in reducing oil and grease, which otherwise can affect
aquatic activities, and contaminate soils and plants. The
high oil and grease reduction efficiency is corroborated by
the findings of Shpiner et al [
25
]. They concluded that
waste stabilization ponds can treat synthetic produced
315
water (PW) and achieve high oil and grease removal levels
(
>
90%). Although the chloride concentration of the final
pond effluent meets regulatory requirements, there are
observed variations in the chloride concentration along
the pond series. These changes in the chloride concen-
320
trations as the sewage passes through the ponds are also
reported by [
26
]. The ponds also achieved high total
coliform and E. coli reduction efficiencies. The progres-
sive removal of pathogens along the series of ponds is
consistent with the findings of Mara et al [
12
]. Stabiliza-
325
tion ponds are generally reported to demonstrate high
pathogen removal efficiencies [
27
,
28
,
29
]. Table1 shows
results of the wastewater parameters analyzed for the
pond series.
Figure 4. TSS Concentration of Pond Effluents
Table 1. Physicochemical and Microbiological Parameters of WSP Samples
Parameter Raw Sewage Pond Pond Pond Pond Pond Pond EPA
1 2 3 4 5 6
pH 7.6 7.6 7.4 7.8 8 9.5 8.9 9-Jun
Conductivity 11860 11480 10800 6360 4620 3119 1410 1500
TDS 6103 5800 5500 3200 2400 1560 854 1000
TSS 1260 1002 720 380 250 150 30 50
Oil & Grease 12.98 12.33 7.24 3.18 1.02 0.11 0.01 100
As 0.89 0.81 0.79 1.48 1.21 1.04 1.3 1.5
Fe 0.71 0.69 2.05 0.99 0.24 0.05 0.14 2
Cu 0.02 0.01 0.05 0.01 <0.01 <0.01 <0.01 2.5
Pb 0.09 0.06 0.02 0.02 0.01 <0.01 <0.01 0.1
Zn 0.08 0.08 0.35 0.012 0.05 0.01 0.02 5
Cl- 261 248 274 212 323 263 177 250
NO3- 2.39 2.08 2.01 0.02 5.19 1.66 0.4 50
Total Coliforms 183744 161600 144000 55200 33200 1256 380 1000
Faecal Coliforms 65000 61000 5200 4000 3100 280 40 1000
E. Coli 298 255 94 53 30 13 3 10
Colour 1198 1120 560 270 140 40 20 200
BOD5 280 103 73 51.4 45.7 15.1 7.6 50
DO 6 6.3 6.4 6 6 6.7 6.8 -
(All concentrations in mg/lexcept pH, Conductivity (µS/cm), Colour (PCU) and the Coliforms(counts/100ml)
Sewage Treatment by Waste Stabilization Pond Systems — 12/13
Figure 5. Nitrate Concentration of Pond Effluents
6. Conclusions and Recommendation
330
The waste stabilization pond system at Obuasi is assessed
to achieve high removal efficiencies of wastewater contam-
inants. The ponds demonstrate high reduction efficiencies
in the physicochemical, microbiological and heavy metal
contaminants levels of the wastewater. Given that the
335
temperature in Obuasi ranges from 22
oC
to 34
oC
, with
rainfall throughout the year, the contaminant removal
efficiencies are not expected to vary significantly during
the year. The waste stabilization pond system is appro-
priate for treating wastewater and produces effluents that
340
meet the recommended microbiological and chemical qual-
ity guidelines at low cost and minimal operational and
maintenance requirements. The wastewater treatment
system is effective and complies with standard wastewa-
ter management practices. The quality of the final pond
345
effluent is not anticipated to have adverse effects on the
environment when discharged into nearby surface water
sources. The waste stabilization pond system provides a
useful method of wastewater treatment and disposal for
growing communities, and therefore should be regarded
350
as a method of choice for treating wastewater in Ghana.
Figure 6. BOD Levels of Pond Effluents
Figure 7. Faecal Coliform Levels of Pond Effluents
References
[1]
B. E. Rittmann, & P. L. McCarty. 2001. Envi-
ronmental Biotechnology: Principles and Applications
(McGraw-Hill, Boston). 355
[2]
I. Papadopoulos, & S. Savvides. 2003. Optimiza-
tion of the use of nitrogen in the treated wastewater
reuse for irrigation, Wat. Sci. Technol., 3, 217-221.
[3]
WHO. 2006. WHO Guidelines for the safe use of
wastewater, excreta and greywater - Wastewater use
360
in agriculture, (World Health Organizations, 2, 222).
[4]
D. D. Mara. 2004. Domestic wastewater treatment
in developing countries, (Earthscan, UK, 293)
[5]
S. Kayombo, T. S. A. Mbwette, J. H. Y. Ka-
tima, N. Ladegaard, & S. E. Jørgensen. 2005.
365
Sewage Treatment by Waste Stabilization Pond Systems — 13/13
Waste stabilization ponds and constructed wetlands
design manual, UNEP-IETC with the Danish Inter-
national Development Agency (Danida), 1 – 59.
[6]
A. Arar.1988. Management aspects of the use of
treated sewage effluent for irrigation, in Treatment
370
and Reuse of Wastewater, Biswas, A.K., and Arar,
A., Eds., Butterworths, London, p. 46.
[7]
D. D. Mara. 1987. Waste stabilization ponds; Prob-
lems and controversies, Wat. Qual. Int., 1, 20-22.
[8]
A., Toumi, A. Nejmeddine, & B. Hamouri. 2000.
375
Heavy metal removal in waste stabilization ponds and
high rate ponds, Wat Sci Tech, 42 10(11), 17 - 21.
[9]
D. D. Mara, & H. W. Pearson. 1998. Design
manual for waste stabilization ponds in Mediterranean
countries, (Lagoon Technology International, Leeds,
380
England, ).
[10]
D. D. Mara, S. W. Mills, H. W. Pearson, &
G. P. Alabaster. 1992. Waste stabilization ponds:
a viable alternative for small community treatment
systems, Water and Environment Journal, 6(3), 72 -
385
78.
[11]
S. M. Oakley, A. Pocasangre, C. Flores, J.
Monge, & M. Estrada. 2000. Waste stabilization
pond use in Central America, the experiences of El Sal-
vador, Guatemala, Honduras and Nicaragua, Water
390
Science and Technology 2000, 42(10-11), 51 – 58.
[12]
D. D. Mara, G. P. Alabaster, H. W. Pearson,
& S. W. Mills.1992. Waste stabilization ponds: A
design manual for Eastern Africa, Lagoon Technology
International, Leeds, England, 591 – 594.395
[13]
D. Ayisah.2011. Assessing the efficiency of the Ako-
sombo wastewater stabilization pond, doctoral diss.,
Kwame Nkrumah University of Science and Technol-
ogy, Kumasi.
[14]
I. O. A. Hodgson. 2000. Treatment of domestic
400
sewage at Akuse (Ghana), Water SA. 26(3), 413 - 415.
[15]
G. Adongo. 2005. AngloGold Ashanti merger - the
new phase of underground mining development in
Ghana, project report, University of Mines and Tech-
nology, Tarkwa.405
[16]
S. J. Arceivala. 1981. Wastewater treatment and
disposal, Pollution Engineering and Technology, Mar-
cel Dekker, Inc. NY, 35 - 56.
[17]
J. P. Arthur. 1983. Notes on the design and opera-
tion of waste stabilization ponds in warm climates of
410
developing countries, (Urban Development Technical
Paper No. 6. World Bank, Washington DC., 106).
[18]
E. Tilley, C. Luethy, A. Morel, C. Zur-
bruegg, & R. Schertenleib. 2008. Compendium of
sanitation systems and technologies, (Duebendorf and
415
Geneva: Swiss Federal Institute of Aquatic Science
and Technology (EAWAG), 180).
[19]
K. J. Bansah, & R. S. Suglo. 2012. Physico-
chemical and microbiological analysis of wastewater in
stabilisation pond, Proceedings of 2nd UMaT Biennial
420
International Mining and Mineral Conference, 36 - 44.
[20]
D. Spuhler. 2012. Wastewater stabilization ponds,
sustainable sanitation and water management,
www.sswm.info. Accessed on 28th March, 2016.
[21]
APHA. 1998. Standard methods for the examination
425
of water and wastewater, (20th edition, American
Public Health Association, Washington DC, 1325).
[22]
Metcalf & Eddy Inc. 1991. Wastewater en-
gineering, treatment, disposal, and reuse, third
ed. (McGraw-Hill Inc., New York, (revised by
430
Tchobanoglous, G. and Burton, F.L.), 1333).
[23]
E. F. Gloyna. 1971. Waste stabilization ponds,
(Geneva: World Health Organization, 175).
[24]
S. Kayombo, T. S. A. Mbwette, A. W. Mayo, J.
H. Y. Katima, & S. E. Jørgensen. 2002. Diurnal
435
cycles of variation of physical–chemical parameters
in waste stabilization ponds, Ecological Engineering,
18(3), 287 - 291.
[25]
R. Shpiner, G. Liu, & D. C. Stuckey. 2009.
Treatment of oilfield produced water by waste stabi-
440
lization ponds: Biodegradation of petroleum-derived
materials, Bioresource Technology, 100(24), 6229 -
6235.
[26]
G. P. Fitzgerald, & G. A. Rohlich. 1958. An
evaluation of stabilization pond literature, Sewage
445
and Industrial Wastes, 30(10), 1213 - 1224.
[27]
A. M. Grimason, H. V. Smith, W. N. Thitai, P.
G. Smith, M. H Jackson, & R. W. A. Girdwood.
1993. Occurrence and removal of Cryptosporidium
spp. oocysts and Giardia spp. cysts in Kenyan waste
450
stabilisation ponds, Water Science and Technology,
27(3-4), 97 - 104.
[28]
H. Arridge, J. I. Oragui, H. W. Pearson, D.
D. Mara, & S. A. Silva. 1995. Vibrio Cholerae 01
and Sallmonellae removal compared with the die-off
455
of faecal indicator organisms in waste stabilization
ponds in northeast Brazil, Water Science Technology,
31 (12), 249 - 256.
[29]
A. E. Knörr, & Torrella, F. 1995. Microbio-
logical performance and Salmonella dynamics in a
460
wastewater depuration pond system of southeastern
Spain, Water Science Technology, 31 (12), 239 – 248.
... Furthermore, in developing countries, conventional methods are rarely geared to produce effluent suitable for disposal into natural watercourses or for reuse in activities such as irrigation (Nhapi and Hoko 2004). In warm climates, Waste Stabilization Ponds (WSPs) which are low energy consuming with minimal operation input are the most well-established method of municipal wastewater treatment (Bansah and Suglo 2016). WSP are highly effective if the algae population can be reduced prior to discharge of the effluent into the environment (Polprasert 2007). ...
... Anaerobic and facultative ponds are designed for biological oxygen demand (BOD) removal while maturation ponds are for pathogen removal, although some BOD removal occurs in maturation ponds and some pathogens in the anaerobic and facultative ponds (Mkude and Saria 2014). Again, as highlighted by Bansah and Suglo (2016), maturation ponds are responsible for removal of pathogens and nutrients. However, the conventional design of maturation ponds does not favor nutrient removal especially phosphorus (Mbwele 2006). ...
... Disposal of effluent of high BOD into surface waters poses a negative impact to the environment; high BOD levels deplete the dissolved oxygen in receiving waters. The depletion of dissolved oxygen results in septic conditions (Bansah and Suglo 2016). The WHP produced an effluent which poses a relatively lower impact to the environment compared with that from the CP and EMP. ...
Article
Full-text available
Donnybrook Waste Stabilization Ponds (WSP) are overloaded and water hyacinth plants have infested the ponds. The study assessed the feasibility of integrating the problematic water hyacinth plants into the current treatment process. Grab samples of influent and effluent for each pond were collected between 28 March and 23 April 2019 and the analysis was done following standard APHA methods. Parameters considered include pH, turbidity, TDS, TSS, TN, TP, BOD, and COD. The raw sewage mean pH, turbidity, TDS, TSS, TN, TP, BOD, and COD were 8.08, 580 NTU, 1639 mg/L, 1294 mg/L, 78 mg/L, 8.16 mg/L, 287 mg/L, and 887 mg/L. The mean pH, turbidity, TDS, TSS, TN, TP, BOD, and COD in the effluent from the existing maturation pond, control pilot pond, and water hyacinth pilot pond were 7.7, 7.7, and 7.3; 75, 67, and 47 NTU; 861, 758, and 668 mg/L; 276, 172, and 82 mg/L; 27, 28, and 17 mg/L; 4, 5.28, and 4 mg/L; 114, 52, and 30 mg/L; and 243, 122, and 81 mg/L. It was concluded that the water hyacinth may be integrated into the WSP system to enhance contaminant removal. The water hyacinth in the ponds should be harvested periodically to avoid secondary organic and nutrient loading from dead plants.
... Intense insolation has destruction effects on coliforms (Bansah and Suglo, 2016). Solar radiation of a wavelength between 425-700 nm affects faecal coliform when absorbed by humic substances in wastewater. ...
... The present study reached cumulative reduction efficiencies between 2 to 4 log units for E. coli and 2 to 3 log units for TC in the two maturation ponds. Similar studies in the tropical environment that achieved related results includes studies by Tyagi et al. (2008) and Bansah and Suglo (2016). ...
Article
Full-text available
Egerton University (EU) uses Wastewater Stabilization Ponds (WSPs) for wastewater treatment. An adjoining wetland with gravel bed substrate and freesurface flow meant to polish discharge before releasing into River Njoro is currently non-operational. The current study aimed at establishing the performance of WSPs in terms of concentration and reduction efficiencies of Faecal Indicator Bacteria (FIB); Total Coliforms (TC) and Escherichia coli (E. coli). Wastewater samples were collected weekly for one month from mid- November to mid-December 2017. Total Coliforms and E. coli were isolated using selective and differential media following Membrane Filtration (MF) method. Colonies were cultured on Chromocult Coliform Agar (CCA) and enumerated using standard procedures for examination of water and wastewater. The results were expressed as Colony Forming Units (CFUs) per 100 ml of the original sample. The inlet showed highest concentration of FIB which reduced along the treatment pathway. Total Coliforms and E. coli ranged between 2.5 × 108 - 2.9 × 1011 and 5.9 × 105 - 1.8 × 1010 CFUs/100 ml respectively with cumulative reduction efficiencies between 2 to 4 log units for E. coli and 2 to 3 log units for TC in the two maturation ponds. Although concentration of FIB in EU WSPs reduces along the treatment pathway, the effluent quality is above recommended international standards for discharge into surface waters. The trend is attributed to lack of frequent monitoring, insufficient maintenance, together with short- circuiting effect due to by-passing of wastewater in the design of the new pond system.
... The results of the physio-chemical and microbial parameters for the wastewater generated from kwata slaughterhouse, treated using waste stabilization pond are presented in table 4. Table 4. Concentration of physio-chemical and microbial parameters of abattoir effluents in WSP Solids in abattoir wastewater are mainly of animal matters and can cause many problems for stream health and aquatic life if in high concentration. The discharge of effluents with high solids concentrations can cause sludge depositions and anaerobic conditions in the receiving water body (Suglo and Bansah, 2016). The concentration of solids in abattoir wastewater generated at kwata slaughterhouse as presented in Table 3, shows that chemical oxygen demand, total solids, total suspended solids and total dissolved solids are 1038.47 ...
Article
Full-text available
The discharge of untreated abattoir wastewater into water bodies results into water quality deterioration of the receiving water bodies. Treatment of abattoir waste using waste stabilization pond is one of such potential cheap and simplest methods of wastewater treatment. A field scale prototype pond which comprises of one anaerobic, facultative and maturation ponds were designed for wastewater treatment. The field scale prototype of waste stabilization pond was reduced to a laboratory-scale model using dimensional analysis. The abattoir wastewater was generated from kwata slaughterhouse and was fed from the equalization tank to the WSP. The results of physio-chemical and microbial parameter conducted show that a laboratory scale model of WSP reduced chemical oxygen demand, nitrate, total solids. total dissolved solids, total suspended solids, phosphate, total and fecal coliform to 10mg/l, 4.93mg/l, 250mg/l, 180mg/l, 70mg/l, 3.95mg/l, 4.04 cfu and 3.98cfu. respectively, the effluents are within the world health organization standard for effluent discharge. This research work is aim at modelling and fabricating a laboratory scale waste stabilization pond model which comprises of anaerobic, facultative and maturation pond, all in series for treatment of abattoir wastewater
... These occurs naturally in surface water as a result of erosion, transport of material from the bottom of the river and tributory inflows, they are also added by industrial effluent example slaughterhouse wastewater discharged directly to the surface water without treatment. TSS are solids in water that can be trapped by a filter, the discharge of effluents with high TSS concentrations can cause sludge depositions and anaerobic conditions in the receiving water body [17]. The percentage removal efficiency of total suspended solids in waste stabilization pond at different hydraulic retention times are shown in Fig. 3 and Table 1. ...
Article
Full-text available
Waste generation at Nigerian slaughterhouses poses a serious threat to the environment because of poor handling practices which results into adverse impact on land, air and water. The aim of this research is studying the dynamics of solid removal in waste stabilization pond at different hydraulics retention times (HRT). The characteristics of wastewater in Kwata slaughterhouse were 991 mg/l, 3427 mg/l and 4419 mg/l. For total suspended solids (TSS), total dissolved solids (TDS) and total solids (TS) respectively. The slaughterhouse wastewater was treated using waste stabilization pond which comprises one anaerobic pond, one facultative pond and one maturation pond. The physio-chemical analysis conducted at the end of the treatment, shows that the total suspended solids (TSS), total dissolved solids (TDS) and total solids (TS) in an effluent leaving the maturation achieved 97%, 92% and 93% removal efficiencies. The physio-chemical analysis results were also subjected to statistical analysis using one-way analysis of variance and two-way analysis of variance without replication. The results show the statistically significant difference exists in the quality of raw wastewater, effluent from anaerobic, facultative and maturation pond.
Article
Developing countries are facing high generation of fecal sludge without adequate systems for proper treatment, leading to detrimental effects on the environment from its disposal. An emerging and innovative option in curbing this problem is the use of epigeic earthworm species to stabilize the waste into vermicompost, a value‐added resource. Substrate enrichment techniques can be applied to promote the sustainability and effectiveness of the vermicomposting process. This study was therefore carried out to determine the potential of two epigeic earthworm species (Eisenia foetida and Eudrilus eugeniae) to transform and stabilize fecal sludge into vermicompost using organic enriched substrates. Enriched substrates were prepared with 160 g of coconut coir, 120 g of fecal matter (65–70% dry matter) and 80 g of organic black soil. Three treatments of the vermibed substrates were prepared which were labelled T1, T2 and T3, with T1 containing Eisenia foetida, T2 containing Eudrilus eugeniae and T3, the control treatment, containing no earthworm. Treatments were triplicated and about 3‐week‐old 20 clitellated, E. fetida (live weight ∼255–275 mg) were introduced into the vermibeds for vermicomposting over a duration of 12 weeks. Physicochemical parameters such as pH, organic carbon (Corg), total nitrogen (Ntot), available phosphorus (Pavail), exchangeable calcium (Caexch), iron (Fe), lead (Pb), and aluminium (Al) changes in the setups at the beginning and end of the vermicomposting period were evaluated. Eisenia foetida demonstrated a higher Corg mineralization (67.59%) compared to Eudrilus eugeniae, which attained 67.22%. Eisenia foetida also showed 5% more mortality than Eudrilus eugeniae. The study revealed that the two epigeic earthworm species for the vermicomposting of fecal waste in the enriched substrates played significant role in stabilizing the waste into vermicompost that was rich in nutrients, with lower levels of metals, higher levels of microbial biomass and higher levels of enzyme concentration.
Article
The scarcity of fresh water for agricultural purposes requires the reuse of wastewater, if the effluent is of acceptable quality and is regularly monitored. The quality of the wastewater in the individual treatment units of waste stabilisation ponds was monitored after desludging and upgrading with a trickling filter unit. The overall hydraulic retention time had increased to 80% of the design value compared to 30% before desludging and upgrading. The biochemical oxygen demand, the chemical oxygen demand, the turbidity, and total suspended solids effluent concentrations were 41 ± 8 mgL⁻¹, 83 ± 9.3 mgL⁻¹, 43 ± 37 NTU, and 45 ± 38 mgL⁻¹ respectively, compared to 40 mgL⁻¹, 190 mgL⁻¹, 145 ± 66 NTU, and 150 ± 127 mgL⁻¹ before desludging and upgrading.The corresponding national thresholds for biochemical oxygen demand, turbidity and total suspended solids are 30, mgL⁻¹, 30 NTU, and 25 mgL⁻¹ respectively. Effluent log counts after upgrading were 2.4 ± 2.32 2.96 ± 2.3, 2.82 ± 2.42, and 2.44 ± 2.37 respectively, for E. coli, and the total coliforms and faecal coliforms compared to 5.4 ± 4.1, 5.1 ± 4.1, and 4.1 ± 23 log counts before upgrading. Helminth eggs were greater than 1 egg L⁻¹ in the final effluent. The pHosphate effluent concentration was greater than the national threshold value (1.5 mgL⁻¹) for discharge into the environment. Desludging and the addition of the trickling filter improved the removal efficiency of some of the contaminants. Operation and maintenance of the system needs to be improved and monitored to find out insights into poor performance even after desludging and addition of a trickling filter unit.
Chapter
Wastewater treatment facilities have high operational costs and are sig- 26 nificant users of energy, due to which <38% percent of municipal as well as 27 industrial wastewater generated by developing countries undergoes treatment of 28 any kind. Waste stabilization ponds (WSPs) are man-made earthen basins used for 29 the treatment of wastewater using individual and/or combination of physicochemical 30 and biological agents with the aim of reducing various contents like nutrients, micro- 31 and macro-pollutants and also removing pathogens from wastewater. Though used 32 worldwide, WSPs are especially suitable for developing countries that have warm 33 climates as they are cost-effective, highly efficient, entirely natural, and highly 34 sustainable. Depending on the required final effluent quality, the ponds can be 35 used individually or connected in a series of anaerobic, facultative, and maturation 36 ponds. This, in turn, is based on what is to be done with the effluent. Whether it is to 37 be used for restricted or unrestricted irrigation or aquaculture or discharged into 38 surface water or groundwater. This chapter gives an overview of various types of 39 WSPs, their design, function, and disinfection processes along with strategies and 40 methods that can be adopted to improve their performance in developing countries
Article
Full-text available
Affordable and effective domestic wastewater treatment is a critical issue in public health and disease prevention around the world, particularly so in developing countries which often lack the financial and technical resources necessary for proper treatment facilities. This practical guide provides state-of-the-art coverage of methods for domestic wastewater treatment and provides a foundation to the practical design of wastewater treatment and re-use systems. The emphasis is on low-cost, low-energy, low-maintenance, high-performance 'natural' systems that contribute to environmental sustainability by producing effluents that can be safely and profitably used in agriculture for crop irrigation and/or in aquaculture, for fish and aquatic vegetable pond fertilization. Modern design methodologies, with worked design examples, are described for waste stabilization ponds, wastewater storage and treatment reservoirs; constructed wetlands, upflow anaerobic sludge blanket reactors, biofilters, aerated lagoons and oxidation ditches. This book is essential reading for engineers, academics and upper-level and graduate students in engineering, wastewater management and public health, and others interested in sustainable and cost-effective technologies for reducing wastewater-related diseases and environmental damage.
Article
Full-text available
Stabilization ponds are now a well established method of biological wastewater treatment. Wherever suitable land is available at reasonable cost, they are usually significantly cheaper than other processes, and they can produce very high quality effluents. Maintenance requirements are very simple, and little or no energy (other than solar energy) is needed. The simplicity and low cost of waste stabilization ponds have made them an attractive proposition in both developed and developing countries. But effective performance depends on correct design.
Conference Paper
Full-text available
Wastewater produced from many industrial operations has to be treated before being allowed to join the natural water body. Wastewater stabilization pond technology (WSPT) is an important natural and cost-effective wastewater treatment method for the removal of pathogenic micro-organisms in tropical countries like Ghana, because of the intensity of the sunlight and temperature. In Ghana, almost all the domestic sewages are discharged into the environment without treatment. To avoid polluting nearby streams and surface water body, sewage generated in the residential areas of Obuasi is managed by applying Waste Stabilisation Ponds Technology. This paper studied the WSPT at Obuasi. Physico-chemical and microbiological analyses were done to the samples collected from wastewater ponds. The results showed that the wastewater quality parameters of the effluent from the last pond meet the threshold values set by the Environmental Protection Agency (EPA), Ghana and can safely be discharged without any adverse effect to the environment. The Biochemical Oxygen Demand, Total Suspended Solids, Nitrate and Faecal Coliforms removal efficiencies of the pond were 97.3%, 99.5%, 83.3% and 99.94% respectively. The wastewater management system was found to be effective and it is recommended to be introduced in all other parts of the country.
Article
Vibrio cholerae O1 was reduced from 40 per litre to zero after 5-10 days, and salmonellae from 130-470 per 100 ml to 1-2 per 100 ml after 13-16 days. Faecal coliforms were better indicators of these bacterial pathogens than were faecal streptococci or Clostridium perfringens, and FC numbers of 1000 per 100 ml were associated with an absence of V. cholerae and 1-2 salmonellae per 100 ml. In-pond survival studies indicated that significant removal of V. cholerae occurs when the sulphide concentration is ≥ 3 mgl-1, thus indicating the need to include anaerobic ponds.
Article
The Salmonella presence and the microbiological quality indicators, total and fecal coliforms and coliphages of E. coli C, have been studied in a overloaded wastewater lagoon system treating urban wastewatrers of the village of Guardamar del Segura (Alicante, Spain). Classical microbiological technology to detect salmonellae was used, including pre-enrichment, enrichment, selective media plating and biochemical and serological confirmation. Water was physicochemically characterized according to COD, SS, temperature, pH and dissolved oxygen. The selective migration step through Rappaport-Vassiliadis semisolid agar medium was essential for the consistent detection of Salmonella in the different lagoon effluents. Total and fecal coliform levels of up to 105-106 MPN/100 ml were detected in the final effluent. High coliphage concentrations of 103-104 pfu/ml were also found in the effluent waters. Salmonella was always detected in 100 ml samples and eventually reached an order of value of 103 MPN/100 ml. Total coliform reduction was higher in the anaerobic ponds whereas fecal coliforms were more efficiently eliminated in the facultative (mostly “anoxic”) lagoons. Coliphage reduction was higher in the facultative lagoons when compared to the anaerobic ponds. On many occasions, no reduction or eventual increment of the concentration of salmonellae was detected in the effluents from the anaerobic ponds compared to concentrations of the patohogen in the influent raw wasterwaters. The possibility exists for a capacity of Salmonella to multiply in the anoxic phase of the wastewater treatment, but the presence of microorganisms in raw sewage waters which could maskSalmonella detection with the enrichment methodology employed cannot be ruled out.
Article
Waste stabilisation ponds are used to treat sewage from the Akuse township. Akuse is located in the Eastern Region of Ghana with a population of about 3 000 people. The whole township has been sewered and the domestic sewage is treated in a series of four waste stabilisation ponds consisting of facultative and maturation processes. The flow rates of both raw and final sewage effluents are about 570 m(3)/d. The weak raw sewage has a BOD and faecal coliform count per 100 ml of less than 100 mg/l and 5 900 000 counts per 100 mt respectively. The final effluent is discharged into the Lower Volta River. The ponds achieve ROD reduction of about 65% and the faecal coliform removal efficiency is about 99.99%. The reduction in suspended solids by the ponds is about 46%. The ammonia and phosphate concentrations of the raw effluent are reduced by about 92% and 94% respectively by the ponds. Under Ghanaian tropical conditions the waste stabilisation ponds have been found to be more suitable and appropriate compared to conventional treatment systems, i.e. trickling filters and activated sludge, because of the ease of operation and maintenance and the high level of treatment efficiencies they are able to achieve. The trend now is to adopt waste stabilisation ponds to replace conventional treatment facilities especially in localities where the cost of maintenance and operation of the conventional facilities seem to be excessive.