index...

Page Title

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)


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



Heliconia psittacorum

Substrate

Diameter (mm) 5

Porosity (%) 48.6

Density: 14 seedlings/m²


Sequential Constructed wetland system:

Feeding tank;

Two sequential HF-CW units;

Effluent tank.

Control without plants


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


Global removal efficiencies Control: 6% HP: 14%


Units A (□) and B (■) contribution for global COD removal efficiency


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


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).


Ammonia Nitrogen

Phase 1 Phase 2




Unit A (□) and unit B (■) contribution for global removal efficiency of NH4+-N


NH4-N removal

NO3 increase

IC removal

Unit A


NH4-N removal

NO3 increase

IC removal

Unit B

NITRIFICATION


Superficial

O2 diffusion Nitrification NH4 NO3

Gradient [N-NH4] N-NH4 Upflow

flux


Organic Matter x Nitrogen

↑ C ↓ Nitrification

Correlation between influent COD:TN and NH4+-N removal rate


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


Total Nitrogen

TN removal: •Unstable •Mainly in units B (when NO3

--N was present) Denitrification


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

Thank you!

Vitor Cano

[email protected]

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


(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


(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.


(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).


(2/12)


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).


(3/12)


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.


(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).


(5/12)


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.


(6/12)


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.


(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.


(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.


(9/12)

Correlation matrix with post-leachate from cesspool


(10/12)

Correlation matrix with post-leachate from pit latrines


(11/12)

Correlation matrix with post-leachate from septic tanks


(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

index...

Documents