Anaerobic Municipal Wastewater Treatment: Comparison and Assessment of Different Design Approaches for UASB-Reactors
©2011
Masterarbeit
118 Seiten
Zusammenfassung
Inhaltsangabe:Introduction:
It is well known that freshwater is finite and an indispensable resource for any living organism on Earth. Inappropriately, during the last decades, anthropogenic activities expansion, in parallel with population growth, has been the main cause of the deterioration of water quality.
According to UNESCO the worlds population is growing nearby 80 million people each year, which suggests an increasing of freshwater demand of about 64 billion m³ a year. Likewise, the demographic estimations indicate that 90% of the 3 billion people, who are expected to be added to the world population in 2050, will be living in developing countries, mainly in regions that are already by this time in water stress.
However, in order to relate the increasing demand for water, not only the demographic aspect should be taken into account but also economic and social aspects must be considered. The economic expansion affects water since there is an increase in the number of consumers as well as modifications in their consumption habits, in a way that services are offered, goods are produced and transported. The social aspect points out to individual rather than collective actions mainly considering poverty, education, culture, lifestyle and consumption patterns. Obviously the demand and the importance for satisfactory sanitation conditions become indispensable. The World Health Organization (WHO) and The United Nations Children's Fund (UNICEF) report that 2.5 billion people still have a lack of access to improved sanitation, including 1.2 billion people who have no facilities at all. While in developed areas the sanitation coverage achieves 99%, in developing regions this number is around 53%. Furthermore, in Latin America and the Caribbean the coverage sanitation is approximately 79%. In Brazil, target area of this study, only 55.2% of the municipalities are covered by a sewage collection system.
In this manner, coverage sanitation does not mean necessarily that the wastewater is treated. Hence, the wastewater must be followed by a treatment system (removal of physical, chemical and biological compounds) in order to achieve pollution mitigation targets for the environmental quality and human health and welfare. According to UNESCO more than 80% of the domestic wastewater in developing countries is discharged untreated, polluting rivers, lakes and coastal areas. Therefore, a large number of technologies have been developed with the intention […]
It is well known that freshwater is finite and an indispensable resource for any living organism on Earth. Inappropriately, during the last decades, anthropogenic activities expansion, in parallel with population growth, has been the main cause of the deterioration of water quality.
According to UNESCO the worlds population is growing nearby 80 million people each year, which suggests an increasing of freshwater demand of about 64 billion m³ a year. Likewise, the demographic estimations indicate that 90% of the 3 billion people, who are expected to be added to the world population in 2050, will be living in developing countries, mainly in regions that are already by this time in water stress.
However, in order to relate the increasing demand for water, not only the demographic aspect should be taken into account but also economic and social aspects must be considered. The economic expansion affects water since there is an increase in the number of consumers as well as modifications in their consumption habits, in a way that services are offered, goods are produced and transported. The social aspect points out to individual rather than collective actions mainly considering poverty, education, culture, lifestyle and consumption patterns. Obviously the demand and the importance for satisfactory sanitation conditions become indispensable. The World Health Organization (WHO) and The United Nations Children's Fund (UNICEF) report that 2.5 billion people still have a lack of access to improved sanitation, including 1.2 billion people who have no facilities at all. While in developed areas the sanitation coverage achieves 99%, in developing regions this number is around 53%. Furthermore, in Latin America and the Caribbean the coverage sanitation is approximately 79%. In Brazil, target area of this study, only 55.2% of the municipalities are covered by a sewage collection system.
In this manner, coverage sanitation does not mean necessarily that the wastewater is treated. Hence, the wastewater must be followed by a treatment system (removal of physical, chemical and biological compounds) in order to achieve pollution mitigation targets for the environmental quality and human health and welfare. According to UNESCO more than 80% of the domestic wastewater in developing countries is discharged untreated, polluting rivers, lakes and coastal areas. Therefore, a large number of technologies have been developed with the intention […]
Leseprobe
Inhaltsverzeichnis
Felipe Teixeira de Carvalho
Anaerobic Municipal Wastewater Treatment: Comparison and Assessment of Different
Design Approaches for UASB-Reactors
ISBN: 978-3-8428-2362-4
Herstellung: Diplomica® Verlag GmbH, Hamburg, 2012
Zugl. Leibniz Universität Hannover, Hannover, Deutschland, MA-Thesis / Master, 2011
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Supervisor:
Klaus Nelting, M.Sc.
Institut für Siedlungswasserwirtschaft und Abfalltechnik
Leibniz Universität Hannover
Examiners:
Prof. Dr.-Ing. K.-H. Rosenwinkel
Institut für Siedlungswasserwirtschaft und Abfalltechnik
Leibniz Universität Hannover
Dr.-Ing. Dirk Weichgrebe
Institut für Siedlungswasserwirtschaft und Abfalltechnik
Leibniz Universität Hannover
"If you think education is expensive, try ignorance."
-- Derek Bok
Abstract
iv
ABSTRACT
The World Health Organization (WHO) and The United Nations Children's Fund
(UNICEF) report that 2.5 billion people have a lack of access to improved
sanitation, including 1.2 billion people who have no facilities at all. While in
developed areas the sanitation coverage achieves 99%, in developing regions this
number is around 53%. Furthermore, in Latin America and the Caribbean the
coverage sanitation is approximately 79%. In Brazil, target area of this study, only
55.2% of the municipalities are covered by a sewage collection system and only
28.5% treat their wastewater.
In this manner, the anaerobic treatment technology emerges as a great alternative
due to its low cost of implementation and operation, minimal mechanisation and
sustainability of the system as a whole. In addition, as developing countries are
mainly situated between the tropics, where the climate is warm most of the time,
the implementation of anaerobic systems is favoured, especially the usage of the
upflow anaerobic sludge blanket (UASB) reactor. As consequence, the UASB
reactor has been spread to many countries in Latin America, for instance Brazil,
Mexico, Colombia, Cuba and Uruguay.
At the Institute of Sanitary Engineering and Waste Management (Institut für
Siedlungswasserwirtschaft und Abfalltechnik ISAH), Leibniz University of
Hannover (Germany), extensive experiments with domestic wastewater and the
usage of the UASB technology in lab and pilot scale were carried out.
Consequently, these experiments together with the collected data were the basis
for Urban (2009) to develop an empirical dimensioning approach of this type of
reactor.
Therefore, the aim of this study is to compare this developed design approach to
another existent approach. Thus, for that purpose the von Sperling and
Chernicharo (2005) design approach was chosen. The main difference between
both approaches lies on the input parameters. While in the von Sperling and
Chernicharo (2005) approach only the total (homogenized) COD is required, in
Urban (2009) a differentiation between homogenized and filtrated COD
(fractioning) is needed. Another important dissimilarity between both approaches
refers to the manner that the procedures are ruled. In Urban (2009) the whole
process is mainly governed by the organic load (sludge loading rate), while in von
Abstract
v
Sperling and Chernicharo (2005) the hydraulics are more significant. This fact is
clearly verified on the estimation of the COD removal, which in von Sperling and
Chernicharo (2005) the concentration of COD in the outflow of the reactor is only a
function of the HRT whereas in Urban (2009) the hydrolysis and biomass growth
are also considered.
Another additional objective of this study is to assess the applicability and
limitations of the Urban (2009) approach in Brazil. For that purpose data (no field
work) of nineteen publications related to the usage of UASB reactor in Brazil was
collected. In this manner, a serious limitation concerning the calculation of the
sludge loading rate (SLR) was found out. Moreover, the SLR precedes all the
steps except for the upflow velocity. For instance, if the SLR crashes all
subsequent process will be miscalculated as well.
It was also found out that the Brazilian pattern of COD removal and wastewater
temperature perform in a range which is not compatible with the Urban (2009)
approach. The total COD removal found in literature, mean of 68% and maximum
of 95%, is higher than the configuration presented by Urban (2009). Moreover,
Urban (2009) established some boundary conditions, which for temperature the
maximum is 35°C, leading to cleaning target of maximum 70% of COD removal.
The incompatibility between the Urban (2009) approach and the Brazilian rates of
total COD removal and temperature is in a such way unclear. One reason might
be the several compounds and parameters that might affect the anaerobic
process, such as microbiology, environmental facts, the reactor construction
aspects, or even the methodology adopted in this study (indirect data
acquirement).
Table of Cont ents
vi
TABLE OF CONTENTS
FIGURES ... VIII
TABLES... X
SYMBOLS AND ABBREVIATIONS ... XII
1.
Introduction...1
1.1.
Objectives...2
1.2.
Structure and methodology ...3
2.
General aspects of Brazil ...5
2.1.
Political division and population ...5
2.2.
Temperature ...6
2.3.
Sanitation situation...7
2.4.
Wastewater characteristics and treatment techniques ... 10
2.5.
Legal requirements ... 12
3.
Principle of biological process ... 15
3.1.
Biomass characterization... 17
3.2.
Bacterial activity ... 18
3.3.
Principles of anaerobic digestion ... 21
3.4.
Environmental requirements and affecting factors ... 26
4.
Anaerobic reactors ... 33
4.1.
UASB reactor: state-of-the-art ... 35
4.2.
UASB reactor usage in Brazil... 42
5.
UASB dimensioning procedures... 53
5.1.
von Sperling and Chernicharo (2005) approach ... 53
5.2.
Urban (2009) approach ... 59
5.3.
Comparison between the Urban (2009) and the von Sperling and
Chernicharo (2005) approaches ... 76
6.
Evaluation of the Urban (2009) approach using data from Brazil ... 79
6.1.
Boundary conditions ... 79
Table of Cont ents
vii
6.2.
Process ... 80
7.
Conclusion and recommendations ... 89
REFERENCES ... 91
APPENDIX ... 96
A.
Data according to Versiani (2005) ... 96
B.
Data according to Busato (2004) ... 98
C.
Data according to Ramos (2008) ... 99
D.
Data according to Francisqueto (2007)... 100
E.
COD removal according to Tessele et al. (2005) ... 101
F.
COD
hom
removal, temperature and HRT according to Busato (2004),
Ramos (2008), Versiani (2005) and Francisqueto (2007) ... 102
G.
COD
out,par
and upflow velocity according to Busato (2004), Versiani
(2005) and Francisqueto (2007) and estimated by the Urban (2009)
approach ... 103
Figures
viii
FIGURES
Figure 1:
Brazil: Regions, Federal States and Capital Cities...5
Figure 2:
Mean monthly temperature of Manaus, Natal, São Paulo, Cuiabá
and Porto Alegre ...7
Figure 3:
Sewage collection system coverage in Brazil ...8
Figure 4:
Number of people without access to sewage collection network in
Brazil and Brazilian Regions ...9
Figure 5:
Percentage of municipalities with sewage treatment, in descending
order, according to the Brazilian Federal States ... 10
Figure 6:
Biological conversion in aerobic and anaerobic processes ... 16
Figure 7:
Specific growth rate as a function of the limiting substrate ... 20
Figure 8:
Scheme of anaerobic process ... 22
Figure 9:
Influence of temperature on the biomass growth rate associated
with psychrophiles, mesophiles and thermophiles group of bacteria . 28
Figure 10: Relation between acetic acid concentration and pH value ... 29
Figure 11: Anaerobic reactors classification ... 33
Figure 12: UASB reactor scheme ... 36
Figure 13: Relation between upflow velocity and hydraulic retention time for
distinct reactor heights ... 41
Figure 14: UASB reactor construction aspects : rectangular and circular types ... 41
Figure 15: WWTP Onça (Minas Gerais Federal State)... 43
Figure 16: Burner at WWTP Franca (São Paulo Federal State) ... 51
Figure 17: UASB reactor with full coverage at WWTP Anhumas/Campinas
(São Paulo Federal State) ... 51
Figure 18: Flowchart adapted from von Sperling and Chernicharo (2005) ... 54
Figure 19: Efficiency of COD removal according to the von Sperling and
Chernicharo (2005) approach ... 57
Figure 20: COD balance according to the Urban (2009) approach ... 61
Figure 21: Urban (2009) design approach flowchart ... 62
Figures
ix
Figure 22: Effect of the upflow velocity in the solid outflow according to the
Urban (2009) approach ... 64
Figure 23: Sludge loading rate as a function of the temperature according to
the Urban (2009) approach ... 66
Figure 24: Effect of temperature on the hydrolysed daily COD load according
to the Urban (2009) approach ... 71
Figure 25: Effect of sludge loading rate and reactor temperature in daily
methane production according to the Urban (2009) approach ... 73
Figure 26: Relation between COD
hom
removal and temperature with SLR
boundary... 82
Figure 27: Relation between COD
hom
removal and temperature according to
Busato (2004), Ramos (2008), Versiani (2005) and Francisqueto
(2007) ... 83
Figure 28: COD
hom
removal distribution according to Busato (2004), Ramos
(2008), Versiani (2005) and Francisqueto (2007)... 84
Figure 29: Temperature distribution according to Busato (2004),
Ramos (2008), Versiani (2005) and Francisqueto (2007) ... 84
Figure 30: COD
out,par
and upflow velocity according to Busato (2004), Versiani
(2005), Francisqueto (2007) and estimated by the Urban (2009)
and the von Sperling and Chernicharo (2005) approaches ... 86
Figure 31: COD
hom
removal and HRT according to Busato (2004),
Ramos (2008), Versiani (2005), Francisqueto (2007) and estimated
by von Sperling and Chernicharo (2005) ... 87
Tables
x
TABLES
Table 1:
Characteristics of domestic wastewater in Brazil... 11
Table 2:
Amount and types of domestic wastewater treatment techniques
used by the municipalities in Brazil ... 11
Table 3:
Discharge standards according to the Resolution 430/2011
CONAMA ... 13
Table 4:
Advantages and disadvantages of anaerobic process ... 16
Table 5:
Optimum pH ranges for the degradation of different substrates ... 29
Table 6:
Nutrient relations in wastewater... 30
Table 7:
Toxic and inhibitory inorganic compounds of anaerobic process ... 31
Table 8:
Toxic and inhibitory organic compounds of anaerobic process ... 31
Table 9:
Advantages and disadvantages of UASB reactors usage ... 36
Table 10: Applicable hydraulic retention time for domestic wastewater in a
4 meter high UASB reactor... 38
Table 11: Recommended upflow velocities for UASB reactors fed with
domestic wastewater ... 40
Table 12:
UASB construction design ... 42
Table 13:
Parameters of UASB reactors in Brazil ... 45
Table 14:
Removal efficiency of UASB reactors in Brazil ... 47
Table 15: Mean concentrations and removal efficiencies for the different
wastewater treatment systems in Brazil ... 49
Table 16: Necessary input data according to the von Sperling and
Chernicharo (2005) approach ... 54
Table 17: Parameters for sludge production ... 56
Table 18: Wastewater characteristics of WWTP Herrenhausen ... 59
Table 19:
Boundary conditions according to the Urban (2009) approach ... 62
Table 20:
Necessary input data according to the Urban (2009) approach... 63
Table 21: Maximum upflow velocity as a function of solid output according to
the Urban (2009) approach ... 65
Tables
xi
Table 22:
Maximum SLR as a function of temperature and COD
hom
reduction
according to the Urban (2009) approach ... 65
Table 23: Minimum sludge bed height as a function of biomass content and
area according to the Urban (2009) approach ... 68
Table 24: Effect of temperature on the hydrolysis activity according to the
Urban (2009) approach ... 70
Table 25: Effect of sludge loading rate and reactor temperature on specific
methane formation according to the Urban (2009) approach ... 72
Table 26:
Outflow fractions load according to the Urban (2009) approach ... 75
Table 27:
Outflow concentrations according to the Urban (2009) approach... 75
Table 28: Reference values for methane losses according to the
Urban (2009) approach ... 76
Table 29: Comparison of input parameters between the von Sperling and
Chernicharo (2005) and the Urban (2009) approaches ... 77
Symbols and Abbreviations
xii
SYMBOLS AND ABBREVIATIONS
Symbol
Description
Units
BOD
5
Biological oxygen demand (consumption in five
days)
[mg/L]
Ca
Calcium
[-]
CETESB
Companhia de Tecnologia de Saneamento
Ambiental (Environmental Sanitation Technology
Company of São Paulo Federal State)
[-]
CH
4
Methane
[-]
Cl
Chlorine
[-]
Co
Cobalt
[-]
CO
2
Carbon dioxide
[-]
COD
Chemical oxygen demand
[mg/L]
COD
fil
Filtered COD
[mg/L]
COD
hom
Homogenized COD
[mg/L]
COD
in
COD inflow
[mg/L]
COD
out
COD outflow
[mg/L]
COD
par
Particulate COD
[mg/L]
CONAMA
Conselho Nacional do Meio Ambiente (Brazilian
National Environmental Council)
[-]
CSTR
Continuously stirred tank reactor
[-]
Cu
Copper
[-]
FC
Faecal coliform
MPN100 m/L
Fe
Iron
[-]
HRT
Hydraulic retention time
[h]
IBGE
Instituto Brasileiro de Geografia e Estatística
(Brazilian Institute of Geography and Statistics)
[-]
ISAH
Institut für Siedlungswasserwirtschaft und
Abfalltechnik (Institute of Sanitary Engineering
and Waste Management)
[-]
K
Potassium
[-]
LCFA
Long chain fatty acid
[-]
Mg
Magnesium
[-]
Mn
Manganese
[-]
Symbols and Abbreviations
xiii
Mo
Molybdenum
[-]
N
Nitrogen
[-]
Na
Sodium
[-]
Ni
Nickel
[-]
P
Phosphorous
[-]
PROSAB
Programa de Pesquisas em Saneamento Básico
(Research Program in Basic Sanitation)
[-]
Q
Inflow rate
[m³/d]
S
Sulphur
[-]
SANEPAR Companhia de Saneamento do Paraná
(Sanitation Company of Paraná)
[-]
Se
Selenium
[-]
SLR
Sludge loading rate
[kgCOD/kgVS·d]
SMA
Specific methane activity
[kgCOD/kgVS·d]
SRB
Sulphate-reducing bacteria
[-]
TN
Total nitrogen
[mg/L]
TP
Total phosphorous
[mg/L]
UASB
Upflow anaerobic sludge blanket
[-]
UNICEF
United Nations Children's Fund
[-]
V
Volume
[m³]
v
Upflow velocity
[m/h]
VHL
Volumetric hydraulic load
[m³/m³·d]
VS
Volatile solids
[mg/L]
VSS
Volatile suspended solids
[mg/L]
WHO
World Health Organization
[-]
WWTP
Waste water treatment plant
[-]
Y
obs
Solids production yield
[kgCOD/kgCOD]
Zn
Zinc
[-]
Introduction
1
1. Introduction
It is well known that freshwater is finite and an indispensable resource for any
living organism on Earth. Inappropriately, during the last decades, anthropogenic
activities expansion, in parallel with population growth, has been the main cause of
the deterioration of water quality.
According to UNESCO (2009) the world's population is growing nearby 80 million
people each year, which suggests an increasing of freshwater demand of about
64 billion m³ a year. Likewise, the demographic estimations indicate that 90% of
the 3 billion people, who are expected to be added to the world population in 2050,
will be living in developing countries, mainly in regions that are already by this time
in water stress.
However, in order to relate the increasing demand for water, not only the
demographic aspect should be taken into account but also economic and social
aspects must be considered. The economic expansion affects water since there is
an increase in the number of consumers as well as modifications in their
consumption habits, in a way that services are offered, goods are produced and
transported. The social aspect points out to individual rather than collective actions
mainly considering poverty, education, culture, lifestyle and consumption patterns.
Obviously the demand and the importance for satisfactory sanitation conditions
become indispensable. The World Health Organization (WHO) and The United
Nations Children's Fund (UNICEF) report that 2.5 billion people still have a lack of
access to improved sanitation, including 1.2 billion people who have no facilities at
all. While in developed areas the sanitation coverage achieves 99%, in developing
regions this number is around 53%. Furthermore, in Latin America and the
Caribbean the coverage sanitation is approximately 79% (WHO/UNICEF, 2008). In
Brazil, target area of this study, only 55.2% of the municipalities are covered by a
sewage collection system (IBGE, 2010).
In this manner, coverage sanitation does not mean necessarily that the
wastewater is treated. Hence, the wastewater must be followed by a treatment
system (removal of physical, chemical and biological compounds) in order to
achieve pollution mitigation targets for the environmental quality and human health
and welfare. According to UNESCO (2009) more than 80% of the domestic
Introduction
2
wastewater in developing countries is discharged untreated, polluting rivers, lakes
and coastal areas. Therefore, a large number of technologies have been
developed with the intention of achieving those standards.
In this scenario, UNESCO (2009) specifies that the high investment costs for
wastewater treatment have been used as a justification for the developing
countries. In this way, many literature publications as von Sperling and
Chernicharo (2005) and Grau (1996) show a variety of available processes for
wastewater treatment, allowing the selection of the most adequate solution,
considering the technical and economic aspect.
Hence, the anaerobic treatment technology emerges as a great alternative due to
its low cost of implementation and operation, minimal mechanisation and
sustainability of the system as a whole (Chernicharo, 2007). In addition, as
developing countries are mainly situated between the tropics, where the climate is
warm most of the time, the implementation of anaerobic systems is favoured
(Foresti, 2002), especially the usage of the upflow anaerobic sludge blanket
(UASB) reactor (Lettinga et al., 1980). Consequently, the UASB reactor has been
spread to many countries in Latin America as: Brazil, Mexico, Colombia, Cuba,
Uruguay (Foresti, 2002).
In recent years, with the increasing demands on wastewater treatment, some
dimensioning procedures have become an important tool. The application of those
approaches in wastewater issues tries to explain how the involved processes, as
microbiology and biochemistry, work out with the intention of designing a tool for
process understanding and optimisation. Furthermore, those procedures stand for
reducing extensive and complex experimental data, observing the correlations
between the performance of the plant and its main design and operating variables
(McCarty & Mosey, 1991).
1.1. Objectives
At the Institute of Sanitary Engineering and Waste Management (Institut für
Siedlungswasserwirtschaft und Abfalltechnik ISAH), Leibniz University of
Hannover (Germany), extensive experiments with domestic wastewater and the
usage of the UASB technology in lab and pilot scale were carried out.
Consequently, those experiments together with the collected data were the basis
Introduction
3
for a developed (empirical) dimensioning approach of this type of reactor (Urban,
2009).
Therefore, the aim of this study is to compare this developed design approach to
another existent approach and to assess the applicability and limitations of this
approach in Brazil, since if compared to Germany, warm countries normally result
in higher temperature inside the reactor, thus higher activity of biomass.
Additionally, the following subtasks are to be considered:
a. Determination of the state-of-the-art of science and technology regarding
anaerobic municipal wastewater treatment with UASB reactors in Brazil.
b. Compilation of data about operation characteristics of existing municipal
UASB reactors in Brazil.
c. Application of the design approach provided by ISAH and the presented
design approaches in subtask a using the collected data in subtask b.
d. Discussion of the computed results in subtask c and assessment of the
applicability and limitations of the used design approach.
1.2. Structure
and
methodology
This study is divided in seven main chapters. The introduction and objectives were
already previously presented. Following, a description of the structure of this study
and the methodology used will be described.
In Chapter 2 some general aspects about Brazil, which is the target area of this
study, will be introduced. It includes particular information about the population,
mean temperature, sanitation situation, characteristics of the domestic
wastewater, main types of wastewater treatment and some legal requirements
involving the release of domestic wastewater as well as standards and specific
conditions for that.
Then, in Chapter 3 the principle of biological process will be presented. Moreover,
a comparison between anaerobic and aerobic treatment systems with their
advantages and disadvantages will be referred. Since the main focus of this study
is anaerobic treatment system, its principle and steps as well as environmental
requirements and some elements that may affect the system well-functioning will
be described.
Introduction
4
Subsequently, in Chapter 4, the main types of anaerobic reactors will be reported.
Since the UASB reactor is the main part of this study, its state-of-the-art, operation
and general required parameters, will be presented. The UASB reactor usage in
Brazil will be also reported, showing its typical configurations, removal efficiencies,
parameters and some operational problems. Additionally, these parameters were
acquired in an indirect way (no field work) through literature research.
In Chapter 5, two UASB dimensioning procedures will be assessed. Firstly, all the
steps involving the approach from von Sperling and Chernicharo (2005), which
was based on studies in Brazil, will be introduced. Then, the main focus of this
study, the Urban (2009) approach, will be described. To conclude, at the end of
this chapter a brief comparison between the two procedures will be additionally
made.
After that, in Chapter 6, all the data and parameters presented in Chapter 4.2 will
be applied with the intention of evaluating and assessing the Urban (2009) UASB
design approach.
As a final point, in Chapter 7, conclusions and recommendations concerning the
UASB approaches, focusing mainly on the Urban (2009) approach, will be related.
General aspects of Brazil
5
2. General
aspects
of
Brazil
The aim of this chapter is an introduction of some general characteristics about
Brazil, which is the target area of this study. Firstly, the political division and some
population aspects will be presented. Then, a general overview of the temperature
will be introduced and lastly, the sanitation situation, wastewater characteristics
and the legal requirements concerning wastewater.
2.1. Political
division
and
population
The Federative Republic of Brazil is divided in 26 Federal States and one Federal
District, as shown in Figure 1, distributed in a total area of 8,547,403.5 km².
Additionally, the Federal States are also sub-divided into Municipalities.
Figure 1: Brazil: Regions, Federal States and Capital Cities
Source: IBGE (n d).
General aspects of Brazil
6
The Brazilian Regions, presented in Figure 1, are groups of Federal States, which
only have the purpose of assisting and guiding public functions without any legal
rights and political autonomy.
According to the results of Census 2010 conducted by the Brazilian Institute of
Geography and Statistics (Instituto Brasileiro de Geografia e Estatística IBGE)
(IBGE, 2011), Brazil's population reached the milestone of 190,755,799
inhabitants.
Compared to the last Census realized in 2000, the population of Brazil grew
12.3%, resulting in an annual average growth of 1.17%. Although this is the lowest
growth rate observed since the beginning of the survey in 1872, the period of
eleven years, from 2000 until 2010, resulted in an absolute increase of 21.0 million
people (IBGE, 2011). Thus, even more people require for public services as
sanitation conveniences, for instance.
2.2. Temperature
The importance of presenting the Brazilian temperature characteristics is due to
the influence of the air temperature on the wastewater temperature, which
consequently affects the treatment process as a whole (see Chapter 3.4.1).
Due to its large territorial area, some Capital Cities of the Brazilian Federal States,
one of each Region, were selected in order to have an overview of the
temperature variation along the year. In Figure 2 the mean monthly temperature of
Manaus (Northern Region), Natal (North-eastern Region), São Paulo (South-
eastern Region), Cuiabá (Midwestern Region) and Porto Alegre (Southern Region)
is shown. Moreover, the exact location of each Capital is presented in the previous
Figure 1.
General aspects of Brazil
7
Figure 2: Mean monthly temperature of Manaus, Natal, São Paulo, Cuiabá and
Porto Alegre
Source: EMBRAPA (n d).
As illustrated in Figure 2, the Capital Cities located in the northern part of Brazil
have a weak variation of temperature along the year, within mean annual
temperature of 30.3 °C in Natal and 26.7 °C in Manaus. In Cuiabá, the mean
annual temperature stands around 25.6 °C, with a minimum of 22.0 °C in July. São
Paulo and Porto Alegre have the mean annual temperature of 20.0 °C and 19.5 °C
respectively, with June and July being the coldest months, reaching the minimum
of 14.3 °C in Porto Alegre.
2.3. Sanitation
situation
In Brazil the sanitation situation has been going through a calamity. However in
the last decades it must be recognized that efforts were made in this field with
improvements in the water supply and wastewater systems.
Considering the municipalities provided with water supply network, the survey
conducted between 1989 and 2008 by IBGE (2010), showed an increase of 3.5%,
reaching 99.4% of the municipalities in the country. The major difference in these
19 years occurred in the north of the country, where it increased from 86.9% of the
municipalities with that service to 98.4%, representing an increase of almost 12%.
10
15
20
25
30
35
Jan
Fev
Mar
Abr
May
Jun
Jul
Ago
Sep
Oct
Nov
Dez
T
e
m
p
er
at
u
re [
°C]
Months of the year
Manaus
Natal
São Paulo
Cuiabá
Porto Alegre
General aspects of Brazil
8
However, when the issue is sewage collection system, Brazil presents a very
catastrophic situation, with only 55.2% of the municipalities covered by it, as
presented in Figure 3. The worst scenario stands in the Northern and North-
eastern Regions, as the Capital City Piauí with coverage of 4.5%. Contrariwise,
Federal States like São Paulo and Rio de Janeiro (South-eastern Region) are
nearly entirely provided with sewage collection systems (IBGE, 2010).
Figure 3: Sewage collection system coverage in Brazil
Source: IBGE (2010).
In Figure 3, the overall population without coverage of sewage collection system,
considering only those municipalities without it, was approximately 34.8 million
people. In 2008, about 18% of the population was exposed to the risk of diseases
due to the lack of sanitary sewer. The Northeast was the Region where the lack of
sewage collection network was more severe, reaching 15.3 million people. The
General aspects of Brazil
9
Northern Region stated with 8.8 million people without sewage collection network,
with 60% concentrated in the south of Pará Federal State. The best scenario can
be observed in the South-eastern Region with 1.2 million people in need of this
service, as shown in Figure 4 (IBGE, 2010).
Figure 4: Number of people without access to sewage collection network in Brazil
and Brazilian Regions
Source: IBGE (2010).
In addition, the main alternative solution adopted to overcome the lack of sewage
collection network was the construction of septic tanks, which has increased
during the last years. This type of solution, which is distant from the desirable,
resulted in a reduction of the release of waste into open ditches, trenches and
water bodies (IBGE, 2010).
However, in order to obtain an adequate sanitation, it is not enough that the
domestic wastewater is just properly collected through a general network. It is also
necessary to have a treatment system for that, which in Brazil the scenario is even
worse. In Figure 5 is shown that only 28.5% of the municipalities treat their
domestic wastewater. Additionally, just three Federal States, have more than half
of the municipalities with a domestic wastewater treatment system: São Paulo
(78.4%), Espírito Santo (69.2%) and Rio de Janeiro (58.7%). The situation is even
worse in the Northern and North-eastern Regions: Pará (4.2%), Rondônia (3.8%),
Piauí (2.2%) and Maranhão (1.4%) (IBGE, 2010).
34.8
8.8
15.3
1.2
6.3
3.2
0
5
10
15
20
25
30
35
40
Brazil
North
Northeast
Southeast
South
Midwest
M
illio
n
s
o
f
p
e
o
p
le
General aspects of Brazil
10
Figure 5: Percentage of municipalities with sewage treatment, in descending
order, according to the Brazilian Federal States
Source: IBGE (2010).
Although less than one third of the municipalities perform a domestic wastewater
treatment, the treated volume (8,460,590 m³/d) represents 68.8% of the entire
collected sewage. This result suggests that municipalities with a treatment system
concentrate a significant portion of the wastewater volume. Moreover, there was
an improvement in this indicator, in 1989 only 19.9% of the domestic wastewater
was treated, representing in the last two decades an increasing of nearly 50%
(IBGE, 2010).
2.4. Wastewater characteristics and treatment techniques
An overview of the characteristics of the domestic wastewater in Brazil is given by
Oliveira and von Sperling (2005), which 166 domestic wastewater treatment plants
in the Federal States of São Paulo and Minas Gerais were evaluated. In Table 1
the respective parameters and their concentration is presented.
78.
4
69.
2
58.
7
48.
9
43.
6
41.
1
28.
5
27.
6
24.
4
22.
8
22.
7
20.
4
20.
2
18.
2
16.
7
16.
3
16.
0
15.
1
13.
3
12.
5
10.
8
9.
3
4.
8
4.
2
3.
8
2.
2
1.
4
0
10
20
30
40
50
60
70
80
90
100
Sã
o
Pa
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lo
Es
p
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ito
Sa
n
to
R
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J
a
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ir
o
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ear
á
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o
Su
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ra
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á
Br
a
si
l
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rn
a
m
b
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c
o
Go
iá
s
R
io G
rand
e do
N
o
rt
e
Min
a
s
G
e
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is
Ba
h
ia
Pa
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A
lag
oa
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a
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o
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nt
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a
ta
ri
na
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io G
rand
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S
u
l
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á
To
c
a
n
tin
s
Se
rg
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az
on
as
Pa
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ia
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s
General aspects of Brazil
11
Table 1: Characteristics of domestic wastewater in Brazil
Parameter
Concentration
a
BOD
463 mg/L
COD
947 mg/L
TSS
366 mg/L
TN
63 mg/L
TP
7 mg/L
FC
1.0×10
8
MPN100 m/L
Source: Adapted from Oliveira & von Sperling, 2005.
a
The concentration values were calculated throughout the arithmetic
mean of the influent.
Due to the large territorial area of Brazil and consequently the expressive variation
of the air temperature between north and south, for instance, it is difficult to
estimate a mean wastewater temperature. Additionally, in Chapter 2.2 is
presented an overview of the air temperature in Brazil, which directly influences
the wastewater temperature. Nevertheless, according to de Brito (2006), the mean
temperature of the domestic wastewater in Brazil along the year does not distance
too much from 20 °C.
The following Table 2 shows which techniques are mostly used in Brazil by the
municipalities in order to treat domestic wastewater.
Table 2: Amount and types of domestic wastewater treatment techniques used by
the municipalities in Brazil
Type of treatment
Number of
municipalities
Facultative lagoon
672
Anaerobic lagoon
431
Biological filter
317
Maturation lagoon
238
Anaerobic reactor
188
Aerobic lagoon
131
Wetland
109
Aerated lagoon
93
Mix lagoon
65
Activated sludge
27
Septic tank
20
Others
694
Source: IBGE (2010).
In Table 2 a predominance of anaerobic systems, as anaerobic lagoon and
facultative lagoon is shown. This is mainly due to the implementation and
contribution of the Research Program in Basic Sanitation (Programa de Pesquisas
General aspects of Brazil
12
em Saneamento Básico PROSAB
1
), which finances researches in the field of
anaerobic treatment, post-treatment of domestic wastewater using anaerobic
reactors (Chernicharo, 2007; Jordão et al., 2009).
2.5. Legal
requirements
Concerning the legal requirements, the Brazilian National Environmental Council
(Conselho Nacional do Meio Ambiente CONAMA) is the responsible organ for
the National Environmental Policy. Additionally, CONAMA, through the Resolution
430/2011, states a guideline providing conditions and standards for wastewater
discharge into water bodies.
A priori, according to the Resolution 430/2011, it is not allowed to release
wastewater in a way that the water quality of the receiving water body becomes
worse. Therefore, in order to directly release wastewater from sewage treatment
systems, the following conditions and specific standards must be fulfilled:
pH between 5 and 9;
Temperature below 40 ° C. In addition, the temperature variation of the
receiving water body should not exceed 3 °C at the edge of the mixing
zone;
Sedimentable materials: maximum of 1 ml/L in 1 hour Inmhoff cone test.
For the release in lakes and ponds, whose velocity is almost zero,
sedimentable materials should be virtually absent;
BOD
5
, 20°C: maximum of 120 mg/L (this limit may be exceeded only in
the case that the wastewater treatment system has an efficiency of at
least 60% of BOD removal); or through study of self-purification of the
water body to prove compliance with the goals of the framework of the
receiving body;
Hexane-soluble substances (oils and fats) until 100 mg/L;
Absence of floating materials.
1
PROSAB is a public action program with the goal of implementing improvements in the sanitation field. It is
financed by Financier of Studies and Projects (Financiadora de Estudos e Projetos FINEP); National Council
for Scientific and Technological Development (Conselho Nacional de Desenvolvimento Científico e
Tecnológico CNPq); and Federal Savings Bank (Caixa Econômica Federal CEF).
Details
- Seiten
- Erscheinungsform
- Originalausgabe
- Jahr
- 2011
- ISBN (eBook)
- 9783842823624
- Dateigröße
- 3.3 MB
- Sprache
- Englisch
- Institution / Hochschule
- Gottfried Wilhelm Leibniz Universität Hannover – Fakultät für Bauingenieurwesen und Geodäsie, Studiengang Water Resources and Environmental Management
- Erscheinungsdatum
- 2014 (April)
- Note
- 1,0
- Schlagworte
- uasb
