INSTALAÇÕES DE TRATAMENTO 1
WASTEWATER TREATMENT
LESSON 9
WASTEWATER TREATMENT
Basic Conceps and Treatment
Steps.Preliminary and primary
treatment
INSTALAÇÕES DE TRATAMENTO 2
WASTEWATER TREATMENT
Typical pollutants to remove at WWTP: BOD5, COD, TSS, N, P and
TC /FC (Total and Fecal coliforms), depending on the receiving
waters and legislation.
BOD5 – Biochemical Oxygen Demand over 5 days and 20ºC (CBO5
in portuguese)
Corresponds to the consumption of oxygen by biological activity in 5
days at 20 ºC. Indicates the amount of oxygen needed to stabilize
biodegradable organic matter
BOD5 (particulate + dissolved) usual range between 200 e 500 mg O2/l.
INSTALAÇÕES DE TRATAMENTO 3
WASTEWATER TREATMENT
COD- Chemical Oxigen Demand) (CQO, in portuguese)
Corresponds to consumption of oxygen via chemical oxidation using a
powerful oxidants (i.e potassium dichromate), during 2h.
The BOD5/CQO of raw urban wastewater varies usually between 0,3
and 0,8. In final treated effluent, the relation varies usually between 0,1
and 0,3.
INSTALAÇÕES DE TRATAMENTO 4
WASTEWATER TREATMENT
Aerobic oxidation (or anaerobic oxidation)
Dissolved Oxygem (blue) and BOD5 evolution (orange)
INSTALAÇÕES DE TRATAMENTO 5
WASTEWATER TREATMENT
TSS interferes with turbitity, light penetration, reaeration, oxygen bentic
demand,
TS (Total Solids) (100%) (example: distribution for domestic wastewater (100ºC) SS (Suspended Solids) (35%) Settleable Solids (60%) (20% in total) Non Settleable solids (40%) (15-20 %) NFS (Non filterable Solids) (65%) Colloidal matter (10%) Dissolved matter (90%) (60% in total ) Volatile (organic (at 600º C)) and fixed Solids
INSTALAÇÕES DE TRATAMENTO 6
WASTEWATER TREATMENT
Removal of TSS and particulate BOD5
in sedimentation tanks
Removal also of dissolved BOD5
in aeration tanks
WASTEWATER TREATMENT
Costa do Estoril System
Control of Bacteriological Contamination
(Total Coliforms ; Fecal Coliforms; E ccoli; Enterococci )
By desinfection (Ex.by ultra-violet radiation,….) or location of
final disposal (long sea outfall)
UV desinfection
Costa do Estoril WWTP
INSTALAÇÕES DE TRATAMENTO 11
WASTEWATER TREATMENT
PRELIMINARY
TREATMENT
PRIMARY
TREATMENT
TERTIARY
TREATMENT
SECONDARY
TREATMENT
Liquid phase and solid phase (sludge)
INSTALAÇÕES DE TRATAMENTO 12
WASTEWATER TREATMENT
Preliminary treatment
Primary sedimentation
Secondary treatment (biological treatment + secondary sedimentation)
Sludge thickening
Sludge digestion
Biogas
INSTALAÇÕES DE TRATAMENTO 13
Removal of coarse solids by interception - racks
and coarse screens (hand-cleaned or
mechanically cleaned);
Removal of grit, sand and gravel - grit chambers;
Equalization (equalization of flow and mass
loading of BOD and TSS) -equalization tanks;
Removal of oil and grease – oil and grease
tanks.
Pre-aeration (control of odors, improve treatability,
removal of grease and grit)
Flocculation
PRELIMINARY
TREATMENT
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 16
WASTEWATER TREATMENT
SCREENS (HAND-CLEANED AND MECHANICALLY CLEANED) (1+1)
INSTALAÇÕES DE TRATAMENTO 18
Removal of settleable solids and floating material
(removal of organic and inorganic suspended solids) –
primary sedimentation tanks (rectangular or circular);
Primary sludge (typically 3 to 5% solids concentration).
PRIMARY
TREATMENT
WASTEWATER TREATMENT
Efficiencies: TSS (»50%) ; BOD5 (»20%) (Decre-law nº 152/97)
Enhanced Primay Treatment (with added chemicals: alum, iron
salts; floculation)-Physico-chemical treatment
INSTALAÇÕES DE TRATAMENTO 19
WASTEWATER TREATMENT
CONVENTIONAL PRIMARY SEDIMENTATION TANK (Circular)
INSTALAÇÕES DE TRATAMENTO 20
WASTEWATER TREATMENT
Main Design Information for Conventional Sedimention Tanks
Detention time – 1,5 to 2,5 h (average flow)
Surface loading Rate (SLR) – 30 to 120 m/day (average to peak
hourly flow).
Depth - >3m
Typical efficiences: TSS (≥ 60%); BOD5 (≥ 30%)
Enhanced primay treatment (including settlers and chemicals:
alum, iron salts) – Much more higher SLR (» 10 m/h ) and lower
detention times.
Efficiencies of TSS and BOD5 removal of respectively over 80%, and
over 50%.
INSTALAÇÕES DE TRATAMENTO 21
WASTEWATER TREATMENT
LESSON 10
WASTEWATER TREATMENT
Secondary Biological – Trickling
filters, activated sludge and ponds.
INSTALAÇÕES DE TRATAMENTO 22
Attached-growth treatment processes (also known
as fixed-film processes): biological treatment
processes in which the microorganisms
responsible for the conversion of the organic
matter or other constituents in the wastewater to
gases and cell tissues are attached to some inert
medium, such rocks or specially designed ceramic
or plastic materials;
Suspended-growth treatment processes: biological
treatment processes in which the microorganisms
responsible for the conversion of the organic
matter or other constituents in the wastewater are
maintained in suspension within the liquid.
Pond processes: Biological treatment by natural
processes, involving the use of bacteria and/or
algae) (anaerobic, facultative, aerobic, maturation
ponds) .
WASTEWATER TREATMENT
MAIN SECONDARY
TREATMENT
(BIOLOGICAL)
INSTALAÇÕES DE TRATAMENTO 23
Trickling filters (low-rate- without recirculation,
high rate and super high rate flow-with
recirculation);
Rotating biological contactors;
Packed-bed reactors.
SECONDARY
TREATMENT
(BIOLOGICAL)
MAJOR ATTACHED
GROWTH
WASTEWATER TREATMENT
The Trickling filters was developed firstly in Salford, England, in
1893, by Joseph Corbett, passing the wastewater through a
rocky media.
INSTALAÇÕES DE TRATAMENTO 24
WASTEWATER TREATMENT
Biofilm
Sprinkler (Euler theoriem)
Trinkling filters
INSTALAÇÕES DE TRATAMENTO 27
WASTEWATER TREATMENT
Design Information for Trickling Filters
ITEM Low rate High rate Super high
rate
Filter Medium Rock, slag Rock, plastic Plastic
Hydraulic loading (m/dia) 1-4 9-37 14-84
BOD5 loading (kg/m3.d) 0,08-0,40 0,5-1,0 0,5-1,6
Depth (m) 1,5-2,4 0,9-1,5 3,0-12,0
Recirculation ratio (-) 0 1-2 1-2
Sloughing (-) Intermittent Continuous Continuos
BOD5 removal efficiency (%) 80-90 68-85 65-80
INSTALAÇÕES DE TRATAMENTO 28
Activated-sludge process:
Conventional (plug-flow);
Continuous-flow stirred-tank;
Pure oxygen;
Extended aeration.
Oxidation ditch
Aerated lagoons.
SECONDARY
TREATMENT
(BIOLOGICAL) MAJOR
SUSPENDED
GROWTH
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 29
WASTEWATER TREATMENT
Reactor
X, V, S
Q , S0 8 Settling tank
(Q – Qw ), S, Xe
Qr , Xr , S
Qw , Xr
The activated sludge was developed in England in 1914 by Arden and Lockett
and was so named because it involved the production of an activate mass of
microorganisms capable of aerobically stabilizing a waste. Many versions of the
original process are in use today, but fundamentally they are all similar. The
system shown in figure is a continuous-flow stirred-tank activated sludge
system.
Q-Flow ; S-Substrate; -Volume;
X-Biomass
Qw, Xr – Excess sludge
Qr, Xr – recirculating sludge
e - effluent
Q
INSTALAÇÕES DE TRATAMENTO 30
WASTEWATER TREATMENT
Operationally, in the activated sludge process organic waste is
introduced into a reactor where an aerobic bacterial culture is
maintained in suspension. The reactor contents are referred to as the
mixed liquor (ML). In the reactor, the bacterial culture carries out the
conversion of organic matter. MLSS is the suspended solids in the
mixed liquor.
The aerobic environment in the reactor is achieved by the use of
diffused air or mechanical aeration, which also serves to maintain the
mixed liquor in a completely mixed regime.
INSTALAÇÕES DE TRATAMENTO 31
WASTEWATER TREATMENT
After a specified period of time, the mixture of new cells and the old
cells (X) is passed into a settling tank where the cells are separated
from the treated wastewater. A portion of settled cells (sludge) (Xr) Is
recycled to maintain the desired concentration of organisms in the
reactor, and a portion is waste (excess sludge). The level at which the
biological mass in the reactor should be kept depends on the desired
treatment efficiency and considerations related to growth kinetics.
INSTALAÇÕES DE TRATAMENTO 32
WASTEWATER TREATMENT
CONTINUOUS-FLOW STIRRED-TANK REACTOR
(MECHANICAL AERATION)
CONTINUOUS-FLOW STIRRED-TANK REACTOR
(MECHANICAL AERATION)
INSTALAÇÕES DE TRATAMENTO 33
WASTEWATER TREATMENT
CONTINUOUS-FLOW STIRRED-TANK REACTOR
(DIFUSED AERATION)
INSTALAÇÕES DE TRATAMENTO 36
WASTEWATER TREATMENT
Typical design information for suspended growth treatment processes)
Process
modification
Qc, (d) F/M
Kg CBO/(kg
MLVSS.d)
Volumetric
loading kg
CBO/(m3.d)
MLVSS (mg/l)
Conventional
Complete-mix
Extended aeration
High purity oxygen
Oxidation ditch
5-15
5-15
20-30
3-10
10-30
0,2-0,4
0,2-0,6
0,05-0,15
0,25-1,0
0,05-0,30
0,3-0,6
0,8-1,9
0,16-0,4
1,6-3,2
0,08-0,5
1500-3000
2500-4000
3000-6000
2000-5000
3000-6000
4-8
3-5
18-36
1-3
8-36
0,25-0,75
0,25-1,00
0,50-1,50
0,25-0,50
0,75-1,50
INSTALAÇÕES DE TRATAMENTO 37
WASTEWATER TREATMENT
Secondary sedimentation tanks (circular)
Extended aeration
SIMARSUL, S.A. / LAGOINHA WWTP (PALMELA)
INSTALAÇÕES DE TRATAMENTO 40
WASTEWATER TREATMENT
POND SYSTEMS (4 different types)
Anaerobic ponds, which are designed to cater for high organic
loading, and are typically absent of DO and contain no significant algal
population. They typically involve long detention times and are deeper
than other types of ponds;
Facultative ponds, which incorporate two different operating modes,
aerobic at the surface and , with the settlement of sludge, anaerobic at
the base of the pond. These ponds are typically shallower than
anaerobic ponds.
INSTALAÇÕES DE TRATAMENTO 41
WASTEWATER TREATMENT
POND SYSTEMS
Aerobic ponds, which are shallow to allow algal development and
receive lower solids and BOD loadings.
Maturation / Oxidation ponds, which essentially are used for polishing
of effluent, and are shallow to allow for ultraviolet light penetration and
subsequent disinfection.
There are also mechanically aerated ponds, which can be deeper
than naturally aerobic ponds, since the aeration will reach the lower
layers. which helps in DO as well as mixing ability to prevent short
circuiting
.
INSTALAÇÕES DE TRATAMENTO 42
Pond systems typically comprise a treatment train, which may involve
a series of ponds:
Anaerobic;
Facultative, aerobic;
Maturation
To achieve BOD reduction (sometimes also nutrient reduction)
(anaerobic and facultative pond) and pathogen reduction (maturation
pond) prior to transfer to the environment (for irrigation reuse or
disposal to receiving waters).
The appropriate treatment train series is dependent on WWTP loading
and requirements of discharges, according to legislation.
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 43
Typical Design Information for Pond Systems
WASTEWATER TREATMENT
Parameter Aerobic
Low rate
Aerobic
Maturation
Aerobic-
anaerobic
facultative
Anaerobic
pond
Aerated
lagoon
Flow regime Intermittently mixed Intermittently mixed Mixed surface
layer
- Completely
mixed
Pond size (há) < 4
multiples
0,8-4,0
multiples
0,8-4,0
multiples
0,2-0,5
multiples
0,1-4,0
multiples
Operation Series or parallel Series or parallel Series or parallel Series Series or
parallel
Detention time (d) 10-40 5-20 5-30 20-50 3-10
Depth (m) 0,9-1,2 0,9-1,5 1,2-2,4 2,4-4,8 1,8-6,0
pH 6,5-10,5 6,5-10,5 6,5-8,5 6,5-7,2 6,5-8,0
Temperature range (ºC) 0-30 0-30 0-50 6-50 0-30
Optimum temperature (ºC) 20 20 20 30 20
BOD5 loading (kg/ha.d) 67-135 ≤ 17 56-202 224-560 20
BOD5 conversion (%) 80-95 60-80 80-95 50-85 80-95
Principal conversion Algae, CO2, bacterial
cell tissue
Algae, CO2, bacterial cell
tissue NO3
Algae, CO2, CH4,
bacterial cell
tissue
CO2, CH4,
bacterial cell
tissue
CO2,
bacterial cell
tissue
Algal concentration (mg/L) 40-100 5-10 5-20 0-5
Effluent suspended solids (mg/L) 80-140 10-30 40-60 80-160 80-250
INSTALAÇÕES DE TRATAMENTO 44
RA
W W
AS
TE
WA
TE
R
SCREENING
GRIT
OIL AND GREASE
REMOVAL
PRIMARY
SEDIMENTATION
BIOLOCICAL
REACTOR
SECONDARY
SEDIMENTATION
TR
EA
TE
D
WA
ST
WA
TE
R
Grit, sand
and gravel
oils and grease
Primary
sludge Coarse solids Recirculated
sludge
Excess
sludge
WASTEWATER TREATMENT
TYPICAL FLOWSHEET OF A WWTP LIQUID PHASE
INSTALAÇÕES DE TRATAMENTO 46
WASTEWATER TREATMENT
LESSON 11
WASTEWATER TREATMENT
Small wastewater treatment
systems.Preliminary design
examples
INSTALAÇÕES DE TRATAMENTO 47
WASTEWATER TREATMENT
Septic tank and final land disposal (ex: infiltration trenches,….)
Typically used for small
communities (< 250 p.e.)
p.e. – population equivalent
Typically used for small communities (< 250 p.e.)
INSTALAÇÕES DE TRATAMENTO 48
WASTEWATER TREATMENT
IMHOFF Tank : Typically used for small communities (< 2000 p.e.)
INSTALAÇÕES DE TRATAMENTO 49
WASTEWATER TREATMENT
Typical Information for Design of Septic tanks
Single , two or three compartment tanks
Detention time – 1 to 2 days
Depht -1 to 1,5 m
Lenght to with ratio - 2:1 to 5:1
Sludge should be removed at least once per two years.
.
INSTALAÇÕES DE TRATAMENTO 50
WASTEWATER TREATMENT
Natural treatment systems (typically for small agglomerations,and at least after primary treatment)
Slow rate (Irrigation) (i.e irrigation of crops)
Rapid Infiltration (sandy soil with high hydraulic condutivity)
Overland flow (over impermeable soils)
Wetlands
(watewater treatment system common in parts of Portugal for
rural small agglomerations: subsurface horizontal flow constructed
wetlands after septic tanks)
INSTALAÇÕES DE TRATAMENTO 51
WASTEWATER TREATMENT
Information for design of subsurface flow constructed wetlands
.
Hydraulic detention time (tr) ≤ 2 days
Height (media) (h) – 0,6 to 0,9 m
Porosity of the media (n) – 0,32
Material characteristics (k) - 0,98 (for sand)
Design expression:
A ≥ Q tr ln (BODinf/BODefl)/(k.h.n.)
A (area); BODinf (influent BOD); BODefl (efluent BODe)
INSTALAÇÕES DE TRATAMENTO 52
WASTEWATER TREATMENT
1st Example: Preliminary Design of a Primary settling tank
Population (P ) – 2000 pe, C = 150 l/(e.p.day) and Inf.Coef. = 0,8
Fav (average flow) = (2000 x150 x 0,8)/86,400 = 2,77 l/s = 240 m3/day
fp (Peak factor) = 1,5 + 60/ 𝑃 =3,4
Finf. (infiltration flow) = 0
Fp (Peak flow)= fp x Fav + Finf = 2,77 x 3,4 x 0 = 9,4 l/s = 813 m3/day
CRITERIA
SLR (surface loading rate) > 30 m/day (for Fav) and < 120 m/day (for Fp) (criteria)
1,5 h < Tr (Detention time) < 2,5 h
𝐴1 ≥240
30 ≥ 8 𝑚2 → 𝐷 ≥
4𝐴
𝜋 ≥ 3,19 𝑚 → 3,2 𝑚
A = 𝜋 x 3,22/4 = 8,04 → SLR (Fp) = 813/8,04 = 101 < 120 m/day
→ ∀ = 8,04 x 2,8 = 22,51 m3
H = 2,8 m; Detention time (tr) = 22,51
240 x24 = 2,25 h
INSTALAÇÕES DE TRATAMENTO 53
WASTEWATER TREATMENT
2nd Example: Preliminary design of a low rate trickling filter
BOD5 load = 2000 x 60 g BOD5/day = 120 kg BOD5/day
CRITERIA
BOD5 loading rate (BL) = 0,08 to 0,40 kg BOD /(m3.day) (criteria)
Hyd. Loading (HL) = 1 to 4 m/day (criteria)
Fav = 240 m3/day 𝐻𝐿 = 1 𝑚/𝑑𝑎𝑦 → 𝐴 = 240 𝑚2
D = 17,5 m
Depth = 2 m → ∀= 240 x 2 = 480 m3
Considering BOD5 Efficiency of settling tank = 30%
BL = 120 x (1-0,3)/480 = 0,35 BOD5/(m3.day) < 0,40
INSTALAÇÕES DE TRATAMENTO 54
WASTEWATER TREATMENT
3rd Example: Preliminary design of a constructed wetland after septic tank
Population – 500 ep; C = 100 l/(ep.day); Inf.Coef. = 0,8
Fav = (500 x 100 x 0,8)/1000 = 40 m3/day = 0,46 l/s
Fp (peak flow) = 2 l/s
BOD5 load = 500 x 60 g BOD5/day = 30 kg BOD5/day; BOD5 BOD5 inf.= 30/40 = 0,750 g/l
Considering BOD5 Efficiency of septic tank – 50%
BOD5 inf = (30 x 0,5)/40 = 0,375 g/l
Data: 𝜂 porosity = 0,32 and Tr = 3 days Tr = detention time; ∀ = volume of the wetland
∀ = 40 x 3
0,32= 375 𝑚3
INSTALAÇÕES DE TRATAMENTO 55
WASTEWATER TREATMENT
3rd Example: Preliminary design of a constructed wetland after
septic tanks (Cont.)
h = 0,7 m → A = 535 m2 (16,37 x 32,73)
A ≥ Q tr ln (BOD5 in /BOD5 efl)/(k h n)
Efficiency of BOD5 removal
BOD5 efl = BOD5 inf exp- (A K h n/(Q tr)
= 0,375 exp - 535 x 0,98 x 0,7 x 0,32)/(40 x2
= 0,088 g/l
BOD5 efficiency of the total system = 0,750−0,088
0,750= 88%
INSTALAÇÕES DE TRATAMENTO 56
WASTEWATER TREATMENT
LESSON 12
WASTEWATER TREATMENT
Technical visit
(Rio da Mula WTP and Valdeão WWTP)
INSTALAÇÕES DE TRATAMENTO 57
Valdeão WWTP, Almada
(Technical visit of 3012-11-26)
Pop – 6 000 e.p. BOD5 inf = 375 mg/l
Fav – 1271 m3/day SST inf = 563 mg/l
Fp – 47,7 l/s CQO inf = 844 mg/l
Effluent requirements (future) (The municipality is considering the up-grading
of the WWTP with disinfection in order to fulfill those requirements)
BOD5 efl = 25 mg/l
CQ efl = 125 mg/l
SST efl = 35 mg/l
FC (MPN/100ml= 2 000 (for discharge in the Tagus estuary)
FC (MPN/100ml= 100 (for irrigation and cleaning)
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 59
Fase Líquida
EE Lamas
Desidratação
Mecânica
(filtro banda)
Espessamento
Gravítico
( V= 6.7 m3)
Meio de disposição final
(aterro sanitário)
Descarga
de Lamas
Desarenador
Gradagem
Águas Residuais
Afluentes
Tanque
Arejamento
Meio receptor
Fase Sólida
EE
Decantador
Secundário
Tanque
Arejamento
Decantador
Secundário
Circuito Principal
Obra de Entrada
Circuito de lamas
Legenda
GradadosMeio de
disposição
final
Areias
Câmara de
distribuição
Parshall
Tanque de
Lamas
(V= 1 m3)
Valdeão WWTP – Treatment scheme
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 61
Valdeão WWTP – Screening Valdeão WWTP – Grit removal and flow
measurement
Valdeão WWTP – Headworks
Valdeão WWTP – Parshal Fume
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 62
Valdeão WWTP – Pumping installation
Valdeão WWTP – Pumping installation
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 63
Valdeão WWTP – Aeration tanks
Valdeão WWTP – Aeration tanks
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 64
Valdeão WWTP – Settling tank
Valdeão WWTP – Settling tank
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 65
Valdeão WWTP – sludge thickening tank
Valdeão WWTP – sludge thickening tank
Valdeão WWTP – sludge filter press equipment Valdeão WWTP – sludge storage tank
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 66
WASTEWATER TREATMENT
LESSON 13
WASTEWATER TREATMENT
Terciary Treatment. Solids Processing
Methods.Legislation.
INSTALAÇÕES DE TRATAMENTO 67
Removal Treatment method
Total suspended solids (TSS) Filtration and microscreening
Microorganisms
Sand filtration
UV disinfection
Maturation ponds
Disinfection with chlorine or ozone
Membrane technologies (microfiltration)
Nitrogen Nitrification /denitrification
Phosphorus Chemical precipitation
Biological processes
MAIN TERTIARY TREATMENT PROCESSES
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 68
WASTEWATER TREATMENT
TERTIARY TREATMENT / SAND FILTRATION
BEIROLAS (LISBON) WWTP
INSTALAÇÕES DE TRATAMENTO 69
TERTIARY TREATMENT / SAND FILTRATION
BEIROLAS (LISBON) WWTP
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 70
TERTIARY TREATMENT / UV Disinfection (MPN FC«2000; TSS«40 mg/l)
GUIA (CASCAIS) WWTP
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 71
TERTIARY TREATMENT / UV DISINFECTION
BEIROLAS (LISBON) WWTP
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 72
WASTEWATER TREATMENT
.
Sludge Wastewater Treatment
The main purpose of sludge stabilization is control of patogenic
microorganisms and odor.
The main purpose of dewatering is to reduce the water content in
the sludge.
INSTALAÇÕES DE TRATAMENTO 73
Unit operation / unit process
or treatment method Function
Preliminary operations:
Grinding
Screening
Degritting
Blending
Storage
Particle size reduction
Removal of fibrous materials
Grit removal
Homogenization of solids streams
Flow equalization
Thickening:
Gravity thickening
Flotation thickening
Centrifugation
Gravity-belt thickening
Rotary-drum thickening
Volume reduction
Volume reduction
Volume reduction
Volume reduction
Volume reduction
Stabilization:
Chemical stabilization
Anaerobic digestion
Aerobic digestion
Composting
Sludge wetlands
Stabilization
Stabilization, mass reduction
Stabilization, mass reduction
Stabilization, product recovery
Stabilization, value indution
Conditioning:
Chemical conditioning
Other conditioning methods
Improve dewaterability
Improve dewaterability
WASTEWATER TREATMENT
SOLIDS PROCESSING METHODS
CHARACTERISTICS OF SOLIDS AND SLUDGE PRODUCED
INSTALAÇÕES DE TRATAMENTO 74
Unit operation / unit process
or treatment method Function
Dewatering:
Centrifuge
Belt-filter press
Filter press
Sludge drying beds
Reed beds (constructed wetland)
Lagoons
Volume reduction
Volume reduction
Volume reduction
Volume reduction
Storage and volume reduction
Storage and volume reduction
Heat drying:
Direct dryers
Indirect dryers
Weight and volume reduction
Weight and volume reduction
Incineration:
Multiple-hearth incineration
Fluidized-bed incineration
Co-incineration with solid waste
Volume reduction, resource recovery
Volume reduction
Volume reduction
Application of biosolids to land:
Land application
Dedicated land disposal
Landfilling
Beneficial use, disposal
Disposal, land reclamation
Disposal
Conveyance and storage Solids transport and storage
SOLIDS PROCESSING METHODS
CHARACTERISTICS OF SOLIDS AND SLUDGE PRODUCED
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 75
SOLIDS PROCESSING METHODS / SLUDGE PUMPING
GUIA (CASCAIS) WWTP
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 76
Sludge
Sand
Gravel
Drains
SOLIDS PROCESSING METHODS
SLUDGE DRYING BEDS (Small WWTP)
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 77
Sludge thickening
Sludge digesters
Biogas storage Heat exchangers
SOLIDS PROCESSING METHODS
LAYOUT EXAMPLE
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 78
Conventional standard-rate single stage process
High-rate, continuous-flow stirred tank, single stage process
SOLIDS PROCESSING METHODS
ANAEROBIC DIGESTION
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 79
Two-stage process
SOLIDS PROCESSING METHODS
ANAEROBIC DIGESTION
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 80
SOLIDS PROCESSING METHODS/ANAEROBIC DIGESTION
BEIROLAS (LISBON) WWTP
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 81
SOLIDS PROCESSING METHODS/ANAEROBIC DIGESTION
Costa do Estoril (CASCAIS/Outeiro da Lota) WWTP-4 km far from
WWTP Liquid phase.
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 82
WASTEWATER TREATMENT
SOLIDS PROCESSING METHODS/ANAEROBIC DIGESTION
BIOGAS STORAGE
INSTALAÇÕES DE TRATAMENTO 83
SOLIDS PROCESSING METHODS/CENTRIFUGE SLUDGE
DEWATERING
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 84
WASTEWATER TREATMENT
SOLIDS PROCESSING METHODS/CENTRIFUGE SLUDGE
DEWATERING
INSTALAÇÕES DE TRATAMENTO 85
SOLIDS PROCESSING METHODS
SLUDGE TRANSPORT BY TRUCK
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 87
SOLIDS PROCESSING METHODS / ODOR CONTROL (Scrubbers)
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 88
PR
IMA
RY
SL
UD
GE
SE
CO
ND
AR
Y S
LU
DG
E
SLUDGE
THICKENING
DIGESTION
(ANAEROBIC)
DEWATERING
(CENTRIFUGATION)
DE
WA
TE
RE
D
SL
UD
GE
WASTEWATER TREATMENT
TYPICAL FLOWSHEET OF A WWTP
SLUDGE TREATMENT
INSTALAÇÕES DE TRATAMENTO 89
WASTEWATER TREATMENT
MAIN LEGISLATION (WASTEWATER)
Decree-law nº 152/97 ,of 19 June (Diretive nº91/271 CEE, of 21 May) (“urban wastewater treatment Diretive”);
Decree-law nº 345/98, of 9 November (1st modification of the DL nº
152/97, concerning requirements for discharging to sensitive zones”)
Decree-law nº 194/2004, of 22 June (2 nd modification of the DL nº 152/97, identification of “ 25 sensitive zones and 9 no sensitive zones) ;
Decree-law nº 188/2008 of 8 October June (3 rd modification of the DL nº 152/97, identification of “18 sensitive and no 3 sensitive zones) ; MAIN LEGISLATION (WASTEWATER TREATMENT SLUDGE)
Decree-law nº 275/2009 of 25 June (use of wastewater treatment sludge for farming pruposes );
INSTALAÇÕES DE TRATAMENTO 90
Decree-law nº 152/97 (Article 2…)
.e. (population equivalent) means the organic biodegradable load having a
five-day biochemical oxygen demand (BOD5) of 60 g of oxygen per day;
primary treatment means treatment of urban waste water by a physical
and/or chemical process involving settlement of suspended solids, or other
processes in which the BOD5 of the incoming waste water is reduced by at least
20 % before discharge and the total suspended solids of the incoming waste
water are reduced by at least 50 %;
secondary treatment” means treatment of urban waste water by a process
generally involving biological treatment with a secondary settlement or other
process in which the requirements established in Table I are respected;
appropriate treatment means treatment of urban waste water by any
process and/or disposal system which after discharge allows the receiving
waters to meet the relevant quality objectives ....
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 91
Decree-law nº 152/97, of 19 June
Pop ≤2000 in fresh waters sensitive zones (or Pop ≤ 10000 in coastal zones):
Appropriate treatment is applicable.
Pop >2000 (or >10000 in coastal zones): Secondary treatment, at least
TABLE 1 Parameter BOD5 CQO TSS*
Concentration (mg/l) and/or
% of reduction
25
70-90
125
75
35
90
*facultativ parameter
For Sensitive zones (risks of eutrophication or bacteriological comtamination)
(Pop >10000 p.e) further treatment ( reduction of NCOD , P ou CF/CT) –
TABLE 2
Parameter P N
Concentration (mg/l)
% reduction
2 (<100 000)
1 (≥100 000) 80
15 (<100 000)
10 (≥100 000)
70-80
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 92
Decree-law nº 152/97 (Cont.) (Artº 4)
Member States shall ensure that urban waste water entering collecting
systems shall before discharge be subject to secondary treatment or
an equivalent treatment as follows:
- at the latest by 31 December 2000 for all discharges from
agglomerations of more than 15 000 p.e.,
- at the latest by 31 December 2005 for all discharges from
agglomerations of between 10 000 and 15 000 p.e.,
-at the latest by 31 December 2005 for discharges to fresh-water and
estuaries from agglomerations of between 2 000 and 10 000 p.e.
-For urban waste water discharging into receiving waters which are
considered sensitive areas..... the Member States shall ensure that
collection systems are provided at the latest by 31 December 1998 for
agglomerations of more than 10 000 p.e.
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 93
Decree-law nº 152/97 (Cont.) (Artº 5)
. Urban waste water discharges from agglomerations of between 10 000 and 150 000 p.e.
to coastal waters ....and between 2 000 and 10 000 p.e. to estuaries situated in “less
senstive” areas may be subjected to treatment less stringent than seconday providing that:
- such discharges receive at least primary treatment; comprehensive studies indicate that
such discharges will not adversely affect the environment.
-..............
Member States shall ensure that urban waste water entering collecting systems shall
before discharge be subject to appropriate treatment in the following cases:
- for discharges to fresh-water and estuaries from agglomerations of less than 2 000 p.e.,
-for discharges to coastal waters from agglomerations of less than 10 000 p.e.
-.............
-In exceptional circumstances, when it can be demonstrated that more advanced treatment
will not produce any environmental benefits, discharges into less sensitive areas of more
than 150 000 p.e. may not be subject to secondary treatment
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 94
Decree-law nº 152/97 (Cont.) (Artº 5)
Member States shall ensure that urban waste water shall before discharge into sensitive
areas be subject to more stringent treatment than secondary treatment, ... from
agglomerations of more than 10 000 p.e.
Discharges from those urban waste water treatment plants shall satisfy the relevant
requirements (tertiary treatment) (Table 2).
Less sensitive areas
A marine water body or area can be identified as a less sensitive area if the discharge of
waste water does not adversely affect the environment as a result of morphology,
hydrology or specific hydraulic conditions which exist in that area
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 95
Decree-law nº 152/97 (Cont.) (Artº 5)
A water body must be identified as a sensitive area if it falls into one of the following
groups:
(a) natural freshwater bodies, estuaries and coastal waters which are found to be eutrophic
or which in the near future may become eutrophic if protective action is not taken.
(b) surface freshwaters intended for the abstraction of drinking water which could contain
more than the concentration of nitrate laid down under ...
(c) areas where further treatment is necessary to fulfil Council Directives (i.e
microorganisms removal...).
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 96
Decree-law nº 149/2004, 22 de June (up dated in 2008)
WASTEWATER TREATMENT
25 sensitive zones (see map)
3 no sensitive zones
(Cabo da Roca, Madeira, Porto Santo)
INSTALAÇÕES DE TRATAMENTO 97
WASTEWATER TREATMENT
LESSON 14 and 15
WASTEWATER TREATMENT
WWTP Photos. Planning of WWTP.
Aspects of detailed projects. Tender
procedures. Hydraulic and
environmental aspects.
Construction and operation.
INSTALAÇÕES DE TRATAMENTO 98
SIMTEJO - Saneamento Integrado dos Municípios do Tejo e Trancão, S.A. is
AdP Group company responsible for the collection, treatment and disposal of
wastewater from the municipalities of Amadora, Lisbon, Loures, Mafra, Odivelas
and Vila Franca de Xira (Tagus and Trancão watersheds) serving a total
population of about 1.5 million inhabitants. The wastewater is conducted to
several pumping stations and WWTP, where it is treated and returned to the
receiving environment or in some cases reused.
The investment plan, to be completed by 2013, includes 32 WWTP, 93 pumping
stations and 339 km of pipes and interceptors.
WASTEWATER TREATMENT
SIMTEJO - SANEAMENTO INTEGRADO DOS MUNICÍPIOS DO TEJO
E TRANCÃO, S.A. / THE COMPANY
INSTALAÇÕES DE TRATAMENTO 99
Municipalities served: Lisbon - Amadora – Oeiras;
Population: 756 000 inhabitants-equivalent;
Dry weather design flow: 3.3 m3/s;
Wet weather design flow: 6.6 m3/s;
Type of treatment: tertiary, comprising:
Pretreatment;
dry weather primary treatment Multiflo;
wet weather primary treatment Actiflo;
secondary treatment Biostyr biofiltration;
UV disinfection;
liming of sludge;
chemical odor control.
Investment: 72 M € (10 M € financed by EU).
WASTEWATER TREATMENT
ALCÂNTARA (LISBON) WWTP
SIMTEJO, S.A.
INSTALAÇÕES DE TRATAMENTO 100
1 WWTP head works 6 Pumping station
2 Pumping station 7 Secondary treatment Biostyr biofiltration
3 Grit / oil and grease removal 8 UV disinfection
4 Dry weather primary treatment Multiflo 9 Sludge treatment
5 Wet weather primary treatment Actiflo 10 Odor control
ALCÂNTARA (LISBON) WWTP
SIMTEJO, S.A.
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 104
Primary sedimentation
Preliminary treatment
Biogas
Sludge digestion
Secondary treatment Tertiary treatment
ALCÂNTARA (LISBON) WWTP
SIMTEJO, S.A.
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 105
WWTP Portinho da Costa, Almada
(preliminary treatment, enhanced primary treatment (DENSADEG) and
biofiltration)
Discharge in the estuary by a long sea outfall
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 106
WWTP Quinta da Bomba, Almada
(preliminary treatment-screening and sand removal; primary treatment, trickling filters.
Thickening and mechanical dewatering of sludge)
(currently up-grading the treatment (filtration and UV desinfection) and anaerobic
digestion of sludge)
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 107
WWTP Machico, Madeira
(preliminary treatment, enhanced primary
treatment, biofiltration and UV disinfection)
Saneamento [A25.5]
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 108
WWTP Meia Serra, Leachate from landfills, Madeira
(Aerated pond, physical-chemical treatment and reverse osmosis)
(treated wastewater reuse for industrial uses)
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 109
WWTP S. João da Talha
(preliminary treatment, equalization tank, physical-chemical treatment
(enhanced primary), activated sludge; sludge anaerobic digestion,
mechanical dewatering).
Discharge in the Tagus Estuary
entrada da ETAR jusante do tratamento primário tanque de arejamento efluente final
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 110
WWTP, Fataca, Odemira
(septic tank and constructed wetland)
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 111
WWTP Sado, Beja
(Stabilization ponds, 32 constructed wetlands (2 ha), and chlorine disinfection.
Treated wastewater reuse for urban park irrigation.
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 112
Ponte de Vagos WWTP, SIMRIA
Example of a WWTP Project, based
on low rate activated sludge
(extended aeration)
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 113
Pop (2030) – 5000 ep
Fav – 5000 m3/day
Fp – 15 l/s
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 121
Casal Novo WWTP, Águas da
Figueira, SA
(Example of a WWTP Project,
based on a constructed wetland)
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 122
Pop (2025) – 100 ep
Cap (2025) – 100 l/hab.day)
Fav – 10 m3/day
Fp – 55 m3day
Wastewaters Septic tank wetland Septic tank
Casal Novo WWTP
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 124
Septic tank Wetland
3 compartments (17,5 x 10) x 0,7
(4,80 x 2,40) x 1,60
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 129
TENDER PROCEDURES (announcement, tender programme, technical and
juridical and legal clauses, technical specifications, project and other technical
documents.)
WITH DETAILED PROJECT (including description and justification, and
drawings)
WITH PRELIMINARY PROGRAM (including established requirements)
WASTEWATER TREATMENT
INSTALAÇÕES DE TRATAMENTO 130
HYDRAULIC AND ENVIRONMENTAL ASPECTS
WASTEWATER TREATMENT
• Gravitic or pumping inflows (continuous or intermittent flows to the WWTP).
• Overflows and “by-pass”.
• Flow measurement: different approaches and flowmeters (critical section;
parshall plume) for WWTP management and invoicing.
• Hydraulic profile (taken into account continuous and local head losses).
• Level of the receiving waters (hydraulic calculations from downstream to up-
stream), effects of climate change-adaptation.
INSTALAÇÕES DE TRATAMENTO 131
HYDRAULIC AND ENVIRONMENTAL ASPECTS
(cont.)
WASTEWATER TREATMENT
• Efficient use of water (reuse) and energy (variable special drivers in
pumps, aeration). Production of energy (turbines; co-generation).
• Use and fate of biosolids/sludge (land application farming; landfilling).
• Equipment and electrical installations.
• Instrumentation and control.
INSTALAÇÕES DE TRATAMENTO 132
WASTEWATER TREATMENT
• Topography for “available heads” – construction of platforms.
• Ensuring access to water and energy. Access to vehicles (circulation)
• Soil foundations – sand? clay? mud? Strategy of construction and groundwater
control (lowering water table by “well point” or other systems).
• Construction aspects and materials – protective coatings; impervious surfaces;
thermic isolation (anaerobic digestion). Structural calculations – Concrete (walls,
pillars, beans in buildings).
LAYOUT CONCERNS
INSTALAÇÕES DE TRATAMENTO 133
WASTEWATER TREATMENT
• Final discharges works.
• Hydraulic circuits: water supply; effluent reuse pipes; irrigation pipes; overflows
and “by-pass” sewers; sludge pipes; storm water and drainage sewers;
recirculation pipes.
• Aesthetic concerns. Green structures.
• Odor and noise control.
• Sampling sections for monitoring.
LAYOUT CONCERNS