Evaluation of the performance of the
wastewater treatment plant in a community in
the province of Cotopaxi
Evaluación del desempeño de la Planta de Tratamiento de
Aguas Residuales en una comunidad de la provincia de
Cotopaxi
David Sebastián Carrasco Lozada
1
Liliana Lizbeth López López
2
Ambar Carolina Yépez Intriago
3
Galo Wilfrido Núñez Aldas
4
Abstract: The objective of this experimental study was to analyze the
performance of the wastewater treatment plant located on the bank of
a river in the province of Cotopaxi, Ecuador. To begin the evaluation,
essential information was collected such as the socioeconomic
activity of the community, the location and size of the plant, the
population served, and the available treatment units, among other
data. Field work was then carried out, which included measuring the
treatment units and the inflow and outflow using the volumetric
method to identify the time of highest demand. Samples were taken,
whose laboratory analysis revealed that some physicochemical
parameters did not comply with the standards established by
TULSMA (Unified Text of Secondary Environmental Legislation) for
discharges into freshwater bodies, especially in the levels of
surfactants and actual color. With all the information gathered and the
theoretical calculations for sizing the treatment units performed, it
was concluded that the FAFA (Ascending Flow Anaerobic Filter)
system was not working properly and that there were cracks in the
septic tank.
Keywords: Physical parameters, chemical parameters, surfactants,
septic tank
Resumen El objetivo de este estudio experimental fue analizar el
desempeño de la planta de tratamiento de aguas residuales situada a
la orilla de un rÃo en la provincia de Cotopaxi, Ecuador. Para
comenzar la evaluación, se recopiló información esencial como la
actividad socioeconómica de la comunidad, la ubicación y tamaño de
la planta, la población atendida, y las unidades de tratamiento
disponibles, entre otros datos. Después, se llevó a cabo un trabajo de
campo que incluyó la medición de las unidades de tratamiento y el
caudal de entrada y salida utilizando el método volumétrico para
identificar el momento de mayor demanda. Se tomaron muestras,
cuyos análisis de laboratorio revelaron que algunos parámetros fÃsico-
quÃmicos no cumplÃan con las normas establecidas por TULSMA
(Texto Unificado de Legislación Segundaria de Medio Ambiente)
Civil Engineer, Independent
davidsebastiancarrasco@gmail.com
https://orcid.org/0000-0003-3913-0331
Master's Degree in Civil Engineering with a
specialization in Metallic Structures
Technical University of Ambato
ll.lopez@uta.edu.ec
https://orcid.org/0009-0004-7730-3162
Master's Degree in Mechanics, Mention in
Manufacturing
Technical University of Ambato
Faculty of Civil and Mechanical Engineering
ac.yepez@uta.edu.ec
https://orcid.org/0009-0006-8443-3269
Master in Teaching and Curriculum for Higher
Education
Technical University of Ambato
Faculty of Civil and Mechanical Engineering
gw.nunez@uta.edu.ec
https://orcid.org/0000-0001-7087-1213
Published
Instituto Tecnológico Superior Edwards Deming.
Quito – Ecuador
Periodicity
July - September
Vol. 1, Num. 22, 2024
pp. 92-100
http://centrosuragraria.com/index.php/revista
Dates of receipt
Received: January 09, 2024
Approved: February 18, 2024
Correspondence author
davidsebastiancarrasco@gmail.com
Creative Commons License
Creative Commons License, Attribution-
NonCommercial-ShareAlike 4.0
International.https://creativecommons.org/licenses
/by-nc-sa/4.0/deed.es
July - September vol. 2. Num. 3 - 2024
93
para descargas en cuerpos de agua dulce, especialmente en los niveles
de tensoactivos y color real. Con toda la información recopilada y los
cálculos teóricos de dimensionamiento de las unidades de tratamiento
realizados, se concluyó que el sistema FAFA (Filtro Anaerobio de
Flujo Ascendente) no funcionaba correctamente y que habÃa grietas
en el tanque séptico.
Palabras clave: Parámetros fÃsicos, parámetros quÃmicos,
tensoactivos, tanque séptico
INTRODUCTION
Water, one of the essential resources for human life, has been under
threat in recent years due to the various uses to which it is put, whether
domestic, industrial, agricultural or livestock. After use, it often does
not receive adequate treatment and, when discharged back into bodies
of fresh or salt water, causes environmental pollution due to its high
load of different physicochemical parameters, such as phosphorus,
nitrogen and fecal coliforms, among others. This situation is aggravated
because treatment plants do not receive adequate maintenance, largely
due to the high cost of these operations. In rural areas, the entities often
have economic limitations and sometimes do not even have treatment
systems (MartÃnez, 1967). (Martinez, 1967)..
Inefficient management of domestic water can cause serious health
problems in the population. Among the most prominent diseases are
digestive disorders, cholera and parasitic infections. These problems are
aggravated by other deficiencies, such as the lack of a potable water
system, sewerage and inadequate waste management. Therefore, it is
essential to conduct talks and training on health and environmental
conservation, especially in the communities where these diseases are
most common. (Pallares & Guaicha, 2014)..
In Latin America and the Caribbean, access to safe drinking water and
basic sanitation is a clear problem. According to a publication by the
Pan American Health Organization (PAHO, 2011), access to safe
drinking water and basic sanitation is a clear problem in Latin America
and the Caribbean. (PAHO, 2011)for 109 years, PAHO has
collaborated with the countries of the Americas in promoting the
prevention and control of waterborne diseases. The organization has
highlighted the precarious conditions of access to water and basic
sanitation, underscoring the need for a serious commitment on the part
of governments and communities. This is because no public health
intervention has a greater impact on the development of a nation and on
individual and collective health than the provision of safe drinking
water and adequate excreta disposal.
Evaluation of the performance of the wastewater treatment plant in a community in the province of
Cotopaxi
94
The lack of safe drinking water and basic sanitation has serious
consequences for development. These factors are the second leading
cause of morbidity and mortality in children under five years of age in
the region and constitute the main component of the burden of
environment-related diseases. However, combined water, sanitation
and hygiene interventions can reduce the prevalence of waterborne
diseases and associated deaths by up to 80% and diarrhea by 50%.
In Ecuador, access to potable water and sanitation has improved
considerably in recent years due to population growth. According to
INEC data (INEC, 2010)in 2006, 82.6% of households nationwide had
an adequate excreta disposal system. By 2014, coverage increased to
91.4%, representing an increase of 8.8 percentage points. The largest
increase was observed in rural areas, where sanitation service coverage
improved by 18.3 percentage points between 2006 and 2014.
According to INEC, in the province of Cotopaxi, the public sewerage
network increased from 24.38% in 2001 to 36.52% in 2010. (INEC,
2010)..
In the Moraspungo parish, wastewater management has been deficient
due to lack of attention from previous administrations. This has caused
a significant environmental impact on the two bodies of freshwater that
flow through the parish: the Piñanato River and the Angamarca River.
Currently, the Moraspungo parish has three wastewater treatment plants
in the urban area and an additional one in the Las Juntas precinct, which
covers 98% of the population in these areas. However, in the rural area,
there is no wastewater treatment system, which means that only
approximately 10% of the parish's population is served.
MATERIALS AND METHODS
To carry out this experimental work, it was divided into four phases to
evaluate the performance of the wastewater treatment plant in the
Moraspungo parish, Pangua canton, Cotopaxi province.
Phase 1: Information gathering
This initial stage is crucial and focuses on collecting detailed
information about the wastewater treatment plant (WWTP) under
study. This includes data such as year of construction, dimensions, and
available treatment units. In addition, a topographical survey of the
July - September vol. 2. Num. 3 - 2024
95
WWTP is carried out and socioeconomic information is collected from
the population.
Phase 2: Analysis of flow behavior in situ
In this phase, the inlet and outlet flow rates of the WWTP are measured
using the volumetric method. It is carried out during six consecutive
days, measuring every hour from 7:00 am to 7:00 pm. The day and hour
with the highest and lowest amount of wastewater is identified, and
samples are taken for physical-chemical analysis in the laboratory.
Phase 3: Laboratory analysis of samples
Wastewater samples taken at peak load times are analyzed in a certified
laboratory. Physicochemical analyses are performed, including
parameters such as oils and grease, BOD5 and COD, phosphorus,
ammonia nitrogen, total nitrogen, pH, suspended solids, among others.
Phase 4: Analysis and verification of the operation of the WWTP
Based on the results of the laboratory analyses, they are compared with
the standards established by Ecuador's TULSMA regulations for
discharges into freshwater bodies. The condition and operation of the
existing structures at the wastewater treatment plant are also evaluated.
This phase concludes with recommendations to improve the operation
of the WWTP.
RESULTS
The wastewater treatment plant is composed of several treatment units,
including a flow regulating tank, a settling tank, a septic tank, a sludge
drying bed and an upflow anaerobic filter. These structures are detailed
in the corresponding diagram (Figure 1).
Evaluation of the performance of the wastewater treatment plant in a community in the province of
Cotopaxi
96
Figure 1. Treatment train units
The most relevant characteristics observed in each of the
aforementioned structures are detailed below:
Sedimenter:
Defects have been observed in the maintenance of this unit, as can be
seen in Figure 2. The accumulation of debris due to these defects is
affecting the functional efficiency of the structure.
Figure 2. Visual diagnosis of the settler
Septic Tank:
Figure 3 shows leaks in the wall adjacent to the sludge drying bed,
caused by the water pressure accumulated in this unit. In addition,
Figure 4 shows suspended solids that have passed through the settler,
July - September vol. 2. Num. 3 - 2024
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as well as the water level that is about to reach the edge of the slab of
this structure, which, according to plant operators, often causes the
water to overflow.
Figure 3. Seepage in the septic tank
Figure 4. Diagnosis of the septic tank
Anaerobic Upflow Filter:
Evaluation of the performance of the wastewater treatment plant in a community in the province of
Cotopaxi
98
This structure is the cause of the failures in the previous units, since it
is located at a higher level than the septic tank, as shown in Figure 5.
This arrangement prevents the water from rising and completing its
process before being discharged into the nearby freshwater body, the
Piñanato River.
Figure 5. FAFA diagnosis
Sludge drying bed:
This structure is as deteriorated as the others in the WWTP, as shown
in Figure 6, which prevents it from performing its function effectively.
The water coming from the septic tank causes the sludge to stagnate,
keeping it always saturated and preventing this infrastructure from
adequately performing the task for which it was designed.
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99
Figure 6. Diagnosis of the sludge drying bed
CONCLUSIONS
The Moraspungo parish wastewater treatment plant is located at UTM
coordinates 697857 East and 9870036 North, near the Piñanato River,
where treated water is discharged. There is no exact information on the
year operations began due to the lack of documentation provided by the
GAD Provincial de Cotopaxi, which was responsible for its
construction and has not provided it to the GAD Municipal de Pangua.
Due to its remote location, maintenance of the treatment plant has been
irregular, especially the septic tank structure, which is in poor condition.
After determining the critical time as Saturday from 11:00 am to 12:00
pm, samples were taken for laboratory analysis. The results revealed
that certain physicochemical parameters, such as surfactants (4.59 mg/l)
and actual color (10.78 color units), exceed the maximum limits
allowed by TULSMA regulations for discharge into freshwater bodies
(0.5 mg/l and 1/20 color units, respectively).
Evaluation of the performance of the wastewater treatment plant in a community in the province of
Cotopaxi
100
A complete structural repair of the WWTP is recommended, focusing
especially on the waterproofing of the septic tank and the removal of
the FAFA stone bed to avoid blockages in the pipes. In addition, it is
proposed to implement a periodic maintenance plan to ensure the proper
functioning of all plant units.
References
INEC. (2010). Population Census 2010. Quito: National Institute of Statistics
and Census.
MartÃnez, P. (1967). Some aspects of sewerage and drainage in Mexico.
Bulletin of the Pan American Sanitary Bureau, 330-336.
PAHO. (2011). Water and Sanitation. Washington: Pan American Sauld
Organization.
Pallares, D., & Guaicha, L. (2014). Environmental Impact Study and
Environmental Management Plan: Samanga sewerage collector and
San Fco. Culapachán treatment. Ambato: Empresa Municipal de
Agua Potable y Alcantarillado de Ambato.
