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1-31
LANDFILL LEACHATE TREATMENT BY CONSTRUCTED WETLAND FOCUSING
ON ORGANIC MATTER AND NITROGEN REMOVAL
Vitor Cano
32-60
EXCELLENCE CENTER FOR DEVELOPMENT COOPERATION
Ngandjui Tchangoue, Yvan Anderson
INDEX
LANDFILL LEACHATE TREATMENT BY
CONSTRUCTED WETLAND FOCUSING ON ORGANIC
MATTER AND NITROGEN REMOVAL
Vitor Cano
PhD Graduate Program in Sustainability
Dr. Marcelo A. Nolasco
Advisor
UNIVERSITY OF SÃO PAULO
BRAZIL
Brazil: 2010
Introduction
No generation Reduction Reuse Recycling
National Policy on Solid Waste
• Closure of existing open dumps
• Implementation of sanitary landfills
• System integration (recycling and composting)
Environmental liabilities historically caused by landfilling: Leachate
Introduction
LC50 (48 h) between 2.2 to 5.7% (v/v) (Sisinno, 2002)
Source: own author
Leachate
Humic/fulvic acids Xenobiotics
Organochlorine Ammonia nitrogen
Toxic metals Others Source: Farquhar (1989)
Introduction
1Fonts: Ferreira et al. (2001), Silva (2002), Fleck (2003), Lange et al. (2006),
Morais et al. (2006), Bidone (2007), Contrera (2008), Costa et al. (2013); 2Fontes: adaptado de Lange e Amaral (2009) e Souto (2009).
OM and N / Variable composition / Toxicity
Landfill leachate characteristics
Parameter Range1 Most Frequent 2
pH 5.8 – 8.4 7.2 -8.6
COD (g.L-1) 1.2 – 14 0.19 – 22
BOD (mg.L-1) 150 – 9,660 <20 – 8,600
NH4-N (mg.L-1) 162 – 1,987 0.4 -1,800
NO3 (mg.L-1) 0.8 - 257 0 – 3.5
Figure – Leachate compounds concentration over time
Source: Farquhar (1989)
Introduction
Landfills in Sao Paulo
Leachate
Municipal Wastewater Treatment Plant: Co-treatment with domestic wastewater
Sludge produced during treatment
Introduction
There is no clearly defined solution to the treatment of
landfill leachate (Abbas et al., 2009)
Sustainable low-cost alternative:
Constructed Wetlands
Constructed Wetlands
Systems designed and constructed to utilize natural
processes to remove pollutants from contaminated water
within a more controlled environment (Wu et al., 2014).
Construction, operation and energy consumption: low cost
Vymazal (2009)
8 Constructed Wetlands
Operation strategies
Oxygen diffused into the system
Constructed wetland performance improvement (Lavrova, 2016).
(Aeration = energy consumption higher cost)
Materials and method
Lab. scale experiment at University of Sao Paulo
Landfill leachate
Guarulhos city Municipal Landfill
(Sao Paulo Metropolitan Region )
13 years of operation
Pre-treatment
Air stripping (HRT 3 days)
Dillution (tap water): 30%
Micro-nutrients addition (Germirli et al., 1991)
Materials and method
Table – Landfill leachate characteristics after pre-treatment
Parameter mg.L-1
(mean ± SD)
Chemical Oxygen Demand 691 ± 129
Total organic carbon 271 ± 73
Inorganic carbon 198 ± 28
Ammonium nitrogen 161 ± 58
Total nitrogen 228 ± 87
Nitrate 3 ± 3
True color* 1010 ± 425
Apparent color* 1480 ± 562
Turbidity** 41 ± 18
*unit: mg PtCo.L-1 **unit: NTU
11
Subsurface Horizontal Flow Constructed Wetland
Fonte: Próprio Autor
Unit
Surface (m²) 0.22
Total Volume (L) 30.5
Net Volume (L) 10.7
Materials and method
Materials and method
Heliconia psittacorum
Substrate
Diameter (mm) 5
Porosity (%) 48.6
Density: 14 seedlings/m²
Materials and method
Sequential Constructed wetland system:
Feeding tank;
Two sequential HF-CW units;
Effluent tank.
Control without plants
Materials and method
Operational
Parameters
Phase 1
(n=16)
Phase 2
(n=26) Unit
Flow 2.6±0.2 2,5±0,8 L.d-1
HRT 8.1±0.7 9,9±3 d
Duration 36 59 d
Leachate 30 30 %
pH adjustment No Yes (7.5) -
Results and discussion
Organic Matter
Results and discussion
Global removal efficiencies Control: 6% HP: 14%
Global removal efficiencies Control: 18% HP: 20%
Units A (□) and B (■) contribution for global COD removal efficiency
Results and discussion
Organic matter: phase 1 x phase 2
Treatment methods that chemically modify leachate
may cause unexpected changes in its toxicity (Marttinen et al., 2002 ).
pH adjustment
• Ammonia Nitrogen
• Organic compounds
• Other compounds
Results and discussion
Organic matter
• Low removal efficiency • No response of nutrients and HRT
Recalcitrance of organic contaminants was reported
as an important limitation for COD removal
(Vymazal, 2009).
Humic acids, fulvic acids and xenobiotic organic
substances are not degraded (Gao et al., 2015).
Results and discussion
Ammonia Nitrogen
Phase 1 Phase 2
Results and discussion
Global removal efficiencies Control: 56% HP: 74%
Global removal efficiencies Control: 43% HP: 58%
Unit A (□) and unit B (■) contribution for global removal efficiency of NH4+-N
Results and discussion
NH4-N removal
NO3 increase
IC removal
Unit A
Results and discussion
NH4-N removal
NO3 increase
IC removal
Unit B
NITRIFICATION
Results and discussion
Superficial
O2 diffusion Nitrification NH4 NO3
Gradient [N-NH4] N-NH4 Upflow
flux
Results and discussion
Organic Matter x Nitrogen
↑ C ↓ Nitrification
Correlation between influent COD:TN and NH4+-N removal rate
Results and discussion
Organic matter x Nitrogen
Microorganism Competition regarding O2 use:
Heterotrophic x Autotrophic
For bioreactors operating in series, the nitrifiers
microorganisms are more abundant in the last
units (Zhu & Chen, 2001).
First units Last units
Oxidation of
biodegradable
organic matter
Oxygen fully
available for NH4+-N
oxidation
Results and discussion
Total Nitrogen
TN removal: •Unstable •Mainly in units B (when NO3
--N was present) Denitrification
Results and discussion
Denitrification
Hampered by lack of readily biodegradable organic matter
as carbon source for microorganisms
Nitrate accumulation
Other routes characterized by partial nitrification and
Anammox may have been partially responsible for
nitrogen removal (Shalini and Joseph, 2012).
•Completely Autotrophic Nitrogen Removal Over Nitrite (CANON)
•Single reactor system for High Activity Ammonia Removal Over Nitrite (SHARON)
Conclusions
• Organic matter removal efficiency as COD was under 20%
• Leachate recalcitrance
• Pre-treatment for biodegradability enhancement
• NH4+-N average global removal efficiencies up to 74%
• Nitrification as the main removal route
• Influent COD:TN
• HRT + Low depth = large area demand
• No significant difference between HP and control
Conclusions
Brazilian National Policy on Solid Waste
• Changes in solid waste management
• Open dumps Landfills = increased leachate collection
• Changes in leachate composition biodegradability
Treatment technology
SUMMER SCHOOL ON
SUSTAINABLE WASTE MANAGEMENT
IN DEVELOPING COUNTRIES AND
EMERGING ECONOMIES
Braunschweig, 31/10/2016
EFFECTS OF MORINGA OLEIFERA SEED EXTRACTS ON THE REMOVAL OF FAECAL BIOINDICATORS FROM
LEACHATE IN VERTICAL FLOW CONSTRUCTED WETLANDS
By
NGANDJUI TCHANGOUE Yvan Anderson
PhD student in Environmental and Organic Chemistry M.Sc. in Organic Chemistry option Biological Chemistry (Univ. Yaoundé I/Cameroon),
M.Sc. in Sanitary and Environmental Engineering (International Institute for Water and Environment Engineering / Burkina Faso)
Wastewater Research Unit / Laboratory of Natural Products and Microbiology, Univ. Yaoundé I Email: [email protected]
1- INTRODUCTION
2- MATERIAL AND METHODS
3- RESULTS AND DISCUSSION
4- CONCLUSION
ACKNOWLEDGEMENTS
TABLE OF CONTENT
• Sub-Saharan Africa countries are characterized by a rapid population growth which bring about severe challenges for accessing household food security and basic services amongst which sanitation (Wethe et al., 2003).
• With 90% of excreta managed by autonomous sanitation, it is a huge amount of faecal sludge that are produced daily and dumped in the environment due to lack of treatment plants. This practice constitutes a serious threat to public health and to the environment (Koné and Strauss, 2004).
• Faecal sludge (FS) or excreta are mixtures of human excrement, urine and wastewater produced from onsite sanitation technologies (e.g. pit latrines, public toilets, septic tanks) (Montangero and Strauss, 2002).
• Heinss (1998) subdivided faecal sludge into two types on the basis of their concentrations: type A and the type B.
INTRODUCTION (1/8)
- Type A faecal sludge are sludge coming from public toilets or public surfaces
(market, hostel, Institute,…) and that are stored for some few days or weeks only.
They are relatively highly concentrated and are biochemically unstable.
- Type B faecal sludge are sludge coming from on-site sanitation disposals (pit toilet,
septic tanks,..). They have been stored for many years and are less concentrated and
partially stable.
In order to protect the environment and mainly water resources, many technologies
are being used worldwide for wastewater treatment. They can be regrouped into two
types according to the amount of wastewater they can threat, thus the number of
equivalent inhabitants which is the main criteria for their dimensioning. We have:
- Intensive processes, we note bacterial filters, biodiscs, activated sludge,
biofiltration, rotating biological contactor (Liénard, 2004; Matamoros et al., 2016).
- Extensive processes, we have constructed wetlands and waste stabilisation pond
(Matamoros et al., 2016). Extensive treatment techniques are treatment processes in
which the culture media are fixed on thin substratum or are free. (Kadlec and Wallace, 2009).
INTRODUCTION (2/8)
• According to WHO, 2012, 10% of the world’s population is thought
to consume wastewater irrigated foods.
• 20 million hectares in 50 countries are irrigated with raw or partially
treated wastewater.
• The use of greywater is growing in both developed and less
developed countries – it is culturally more acceptable in some
societies
Wastewater can be an excellent resource…. if it is managed safely.
INTRODUCTION (3/8)
There have been many attempts to implement intensive wastewater
treatment technologies (e.g. rotating biological contactors, activated
sludge…), but they have proved not adapted to the African context for a
number of reasons including the high cost of installation, the
unavailability of a reliable energy supply, and insufficient local skills and
human resources.
INTRODUCTION (4/8)
Fig.1: Intensive wastewater treatment technologies previously used in Cameroon
• The development of research on this issue of treatment of wastewater and faecal sludge through simple and appropriate systems adapted to the socioeconomic context of African countries has been a concern for several years.
• “Natural” or passive systems also termed low-cost technologies (Strauss et al., 1997) such as planted drying beds for sludge and wastewater (i.e. vertical flow constructed wetlands (VFCWs)) provided a promising alternative.
• Among the techniques used, planted drying beds, which have been widely studied, have proved their efficiency in removing particulate and inorganic carbon pollution contained in wastewater and faecal sludge (Kengne et al., 2008 ; Fonkou et al., 2010 ; Soh et al., 2014).
INTRODUCTION (5/8)
• Their use for treatment of wastewaters from municipal, surface, storm,
industrial, and agricultural sources has been well established (Cofie et
al., 2006; Cooper, 2005; Kadlec and Wallace, 2009; Liénard et al.,
2004; Stefanakis and Tsihrintzis, 2012; Vymazal,2007).
• In Cameroon, the use of this technique for the treatment of faecal
sludge is recent. Echinochloa pyramidalis has been selected by Kengne
et al. (2008) as auxiliary macrophyte because of its good treatment
capacity (good liquid / solid separation), rapid reproduction, its easy
management, its biomass recycling options and its reduction of
pollutants. Despite the good performance of solid / liquid separation of
planted sludge drying beds with Echinochloa pyramidalis, leachates
released by their high physical, chemical and bacteriological
characteristics showed the need for additional refining treatment before
discharge in nature (Kengne et al., 2008, Kengne et al., 2011).
INTRODUCTION (6/8)
• The use of an additional planted sludge drying beds with
Echinochloa pyramidalis to meet this demand has produced very
good results on the physicochemical level, though the
bacteriological aspect remains problematic (Soh et al., 2014).
• Recent studies have shown a strong disinfectant action of the
coagulant from the seeds of Moringa oleifera with performances
averaging 82-94%, 81-100% and 94-100% for faecal coliforms,
Escherichia coli and faecal streptococci, respectively, when
treating water intended for consumption (Kabore et al., 2013) and
performances around 96.1% and 82.8% for total coliforms and
Escherichia coli, respectively, during the treatment of domestic
wastewater (Marcelo et al., 2013).
INTRODUCTION (7/8)
• The aim of the present study was to evaluate to what
extent natural extract from Moringa oleifera seeds can be
effective in polishing effluent from VFCW in 3rd stage
treatment and how the concentration of extract and the
duration of decantation affect treatment performances.
INTRODUCTION (8/8)
• Site investigation
This study was conducted in-situ using pilot-scale Vertical Flow Constructed Wetlands
(VFCW) installed on the campus of the University of Yaoundé I for the field part and in
the Laboratory of Biotechnology and Environment at the University of Yaoundé I for
the lab part.
• Experimental set up
MATERIAL AND METHODS
(1/4)
Fig.2: Different steps of construction of the VFCW
• Collecting of faecal sludge and post leachate
Fig.3: From faecal sludge to post leachate for analyses
MATERIAL AND METHODS
(2/4)
• Parameters considered
Some physico-chemical parameters like pH, temperature and redox potential (E)
were assessed in situ. Conductivity, salinity and Total Dissolved Solid (TDS) were
analysed in the laboratory according to the standard methodology (APHA, 2005).
The faecal indicators of water pollution: Escherichia coli, faecal coliforms and
faecal streptococci were also determined and quantified with the membrane
filtration method and counted according to the standard protocol described by
Rodier et al. (2009).
Fig.4: Different steps of analysis of the parameters considered
MATERIAL AND METHODS
(3/4)
• Extraction of coagulant from Moringa oleifera seeds
The seeds were dried, peeled and crushed according to the technique described by Folkard
and Sutherland (2002).
Coagulation efficiency of M. oleifera seed extracts was assessed using the jar test in
laboratory experiments (Muyibi and Alfugara, 2003; Ndabigengesere et al., 1995).
According to literature (Amagloh et al., 2009; Sengupta et al., 2012; Kabore et al., 2013;
Marcelo et al., 2013), different concentrations of coagulant (30 mg, 40mg and 50mg) were
added to each triplet of glass and stirred. After stirring, each triplet was allowed to settle for
three varying times (1h, 2h and 3h). Agitation of samples after the introduction of M.
oleifera extract was in two phases: rapid stirring at 200 rpm for five minutes and slow stirring at 50 rpm for twenty minutes. • Data analysis Data from the laboratory experiments were
expressed as means and standard deviations (SD)
and performed with statistical software GraphPad
Prism 5.03 using ANOVA following Newman
Keuls’ multiple comparison tests.
MATERIAL AND METHODS
(4/4)
Characteristics of different effluents from Vertical Flow Constructed Wetlands
RESULTS AND DISCUSSIONS
(1/12)
Parameters
Units
Cesspool Pit latrines Septic tanks Guidelines for
discharge of effluent
Mean SD* Mean SD* Mean SD* MINEP** WHO***
Eh (mV) 21.03 25.44 29.43 30.73 8.67 57.27 NA NA
TDS (mg/L) 248.67 16.44 869.67 69.57 670.00 339.69 NA 450-2000
pH 6.38 0.59 6.14 0.52 6.49 0.96 6.0-9.0 6.5-8.0
Temperature °C 26.93 0.29 26.37 1.62 28.50 0.79 NA NA
Salinity (‰) 0.25 0.02 0.87 0.08 0.85 0.23 NA 0.7-3.0
Conductivity (µs/cm) 516.67 35.57 1734.00 133.37 1341.00 661.05 NA NA
Escherichia
Coli
(Log CFU
/100 mL)
4.59 3.81 4.85 4.30 6.44 6.24 <3.3 <3.0
Faecal
streptococci
(Log CFU
/100 mL)
4.63 4.07 5.45 4.88 6.40 5.90 <3.0 NA
Faecal
coliform
(Log CFU
/100 mL)
4.98 4.32 5.75 4.96 6.76 6.45 <3.30 <3.0
This table shows differences on the characteristics of the three post-leachate of the faecal sludge used.
Looking at the distribution of physicochemical parameters, it was observed that pit latrines exhibited higher
TDS, salinity and conductivity than septic tanks and cesspool. Concerning bacteriological parameters, E. coli,
faecal coliform and faecal streptococci are higher in effluent from faecal sludge of septic tanks than others.
We also observed that effluent from faecal sludge of cesspool have smaller characteristics.
Effects of concentrations of Moringa oleifera extracts at fixed
settling time on bacteriological characteristics in cesspool
In the post-leachate from cesspool, the effect was really appreciated for concentration of
50 mg during 180 min decantation time for faecal bio indicators. During these 3 hours,
a total of 0.56 ulog, 0.62 ulog and 0.76 ulog, respectively, of E. coli, faecal streptococci
and faecal coliforms were removed. Decantation time was significant (p= 0.0119 –
0.0345) for E. coli (Fig. 2B), significantly higher (p= 0.0065 – 0.0213) for faecal
streptococci (Fig. 2C) and highly significant (p= 0.0004 – 0.0017) for faecal coliforms
(Fig. 2A).
RESULTS AND DISCUSSIONS
(2/12)
Effects of concentrations of Moringa oleifera extracts at fixed
settling time on bacteriological characteristics in pit latrines
The effect was also appreciated in the post-leachate from pit latrines during three times
of decantation (60 min, 120 min and 180 min) for concentrations of 40 mg and 50 mg.
During 3 hours, a total of 0.88 ulog and 0.93 ulog of faecal coliforms and E. coli were
removed with a concentration of 40 mg, and 0.63 ulog of faecal streptococci were
removed with a concentration of 50 mg. The Effect was significant (p= 0.0201 –
0.0398) for faecal streptococci (Fig. 2E) and of higher significant (p= 0.0004 – 0.0128)
for E. coli (Fig. 2D), (p <0.0001 – 0.0003) for faecal coliforms (Fig. 2F).
RESULTS AND DISCUSSIONS
(3/12)
Effects of concentrations of Moringa oleifera extracts at fixed
settling time on bacteriological characteristics in septic tanks
With the post-leachate from septic tank, no significant reduction in E. coli
(Fig.2G) and faecal coliform (Fig. 2I) was recorded but a slightly significant
reduction (p= 0.0252 – 0.0373) was noted with faecal streptococci (Fig. 2H).
During the 3 hours, a total of 0.67 ulog of faecal coliforms were removed with
a concentration of 40 mg, 0.73 ulog and 0.88 ulog, respectively, of faecal
streptococci and E. coli were removed with a concentration of 50 mg.
RESULTS AND DISCUSSIONS
(4/12)
Effects of different settling times of decantation at fixed concentrations of
Moringa oleifera extracts on bacteriological characteristics in cesspool
In the post-leachate from cesspool, the effect of adding
concentration of M. oleifera extract was significantly high (p=
0.0019 – 0.0317) for faecal coliform (Fig. 3C) and highly
significant (p= 0.0006 – 0.0042) for E. coli (Fig. 3A), (p=
0.0006 – 0.0031) for faecal streptococci (Fig. 3B).
RESULTS AND DISCUSSIONS
(5/12)
Effects of different settling times of decantation at fixed concentrations of
Moringa oleifera extracts on bacteriological characteristics in pit latrines
This effect was highly significant (P= 0.0003 – 0.0028) for E.
coli (Fig. 3E), (p= 0.0001 – 0.0004) for faecal streptococci
(Fig. 3D) and (p < 0.0001) for faecal coliform (Fig. 3F) in the
post-leachate from pit latrines.
RESULTS AND DISCUSSIONS
(6/12)
Effects of different settling times of decantation at fixed concentrations of
Moringa oleifera extracts on bacteriological characteristics in septic tanks
The effect of adding the concentration of M. oleifera was
significant (p= 0.0161 – 0.0605) for E. coli (Fig. 3G), of higher
significant (p= 0.0034 – 0.0232) for faecal streptococci (Fig. 3I)
and highly significant (p= 0.0005 – 0.0022) for faecal coliform
(Fig. 3H) in the post-leachate from septic tank.
RESULTS AND DISCUSSIONS
(7/12)
Best concentration and settling time of Moringa oleifera extract
The ideal concentration of M. oleifera extract was highly
dependent on the types of faecal sludge and their
characteristics (Fig. 2&3). The optimum dosage for the
treatment of faecal sludge from cesspool was 50 mg for E.
coli, faecal coliforms and faecal streptococci for180 min. For
pit latrines, the optimum dosage was 40 mg for E. coli and
faecal coliforms for 180 min and 50 mg for faecal streptococci
for 180 min. For septic tanks, 50 mg of extract for 180 min
was selected as optimum dosage for E. coli and faecal
streptococci, and 40 mg for 180 min too for faecal coliforms.
RESULTS AND DISCUSSIONS
(8/12)
Effect of treatment with Moringa oleifera on pH
Cesspool Pit latrines
Septic tank
Before After treatment Before After treatment Before After treatment
treatment Conditions Mean treatment Conditions Mean treatment Conditions Mean
pH 6.38±0.59 50mg - 2h 6.37±0.73
6.14±0.52 50mg - 1h 6.48±0.59
6.49±0.96 30mg - 1h 6.64±1.03
50mg - 3h 6.24±0.65 50mg - 2h 6.43±0.61 30mg - 3h 6.24±0.69
It is noted that treatment with M. oleifera has little influence
on the pH. There is a slight increase in pH with post-leachate
from pit latrines, a slight decrease in pH with post-leachate
from cesspool and a slight reduction and increase in pH with
post-leachate from septic tank. No significant change of pH is
observed.
RESULTS AND DISCUSSIONS
(9/12)
Correlation matrix with post-leachate from cesspool
RESULTS AND DISCUSSIONS
(10/12)
Correlation matrix with post-leachate from pit latrines
RESULTS AND DISCUSSIONS
(11/12)
Correlation matrix with post-leachate from septic tanks
RESULTS AND DISCUSSIONS
(12/12)
The results showed that Moringa oleifera seeds extract was able to reduce the
percentage of Escherichia coli by 72.87 – 88.1%, faecal streptococci by 75.60
– 81.33% and faecal coliforms by 78.49 – 86.39% in different effluents of
faecal sludge used. The best removal efficiency for Escherichia coli and faecal
coliforms were obtained in the faecal post-leachates from pit latrines with
values of 88.1% and 86.39% removal efficiencies respectively and for faecal
streptococci it was in the post-leachates of septic tanks with values of 81.33%
removal efficiency. Considering the fact that Moringa oleifera can be locally
obtained due to its availability in many tropical countries, its use in faecal
sludge leachate post treatment should be encouraged in order to reduce both
the contamination risk and the high cost of the current wastewater treatment
systems. However, additional improvements of leachate are suggested to meet
the WHO and MINEP guideline thresholds for discharge or reuse in non-
restricted agriculture.
CONCLUSION
ACKNOWLEDGEMENTS
THANK YOU
FOR YOUR KIND
ATTENTION