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ECOTOXICOLOGICAL IMPACTS OF LANDFILL
LEACHATE AND ITS TREATMENT USING GREEN
COAGULANTSAGAMUTHU PARIATAMBY, KEE YANG LING, NURUL ASYIKIN BT AHAZAR
CENTER FOR RESE ARC H IN WAS TE MAN AGEMEN T
I N S T I T U TE O F B I O L O GI C AL S C I E N C E S , U N I V E R S I T Y O F M AL AYA, 5 0 6 0 3 , K U AL A L U M P U R , M ALAY S I A
1
Landfill ImpactsA large number of impacts may occur from landfill operations. These impacts can include:
Injuries to wildlife
Infrastructure damage
Pollution of the local environment
Harbouring of disease vectors (such as rats/flies)
Methane is generated (by decaying organic wastes)
Fatal accidents (such as scavengers buried under waste piles)
3
Landfill Leachate During landfill site operation, a liquid known as leachate is produced. 3-4 million L/d in Malaysia.
It is a mixture of organic degradation products, liquid waste and rain water.
It has high organic carbon content and high concentrations of nitrogen
This liquid is highly toxic and can pollute the land, ground water and water ways
4
Landfill Toxins Many materials that end up as waste contain toxic substances.
Over time, these toxins leach into our soil and groundwater, and become environmental hazards for years.
Electronic waste is a good example.
Waste such as televisions, computers and other electronic appliances contain a long list of hazardous substances, including mercury, arsenic, cadmium, PVC, solvents, acids and lead.
5
Landfill Leachate Leachate contain compounds such as alkenes, ketones, esters, alcohols, polycyclic aromatic hydrocarbons (PAHs), phthalates, phenols, nitrogen compounds, carboxylic acids, amines, amides, aldehydes and carbohydrates (Dorian et al., 2013).
Persistent Organic Pollutants (POPs) are major concern in leachate due to their toxicity, persistence, long distance travel and bioaccumulation in animals.
More than 1000 chemicals were identified in contaminated groundwater at landfill site.
6
POPs Definition
POPs are organic compounds that resist chemical, biological and photolytic degradation due to their inherent characteristics.
7
Categories of POPs The intentionally produced POPs include: - pesticides and industrial chemicals that may be traded between countries.
The unintentionally produced POPs which are by-products of industrial or other processes involving combustion which are not products in commerce.
8
POPs Characteristics
Highly persistent
Long range transportability
Bio-accumulation
Highly toxic
(Source: Tang, 2013)
9
POPS cont’d
POPs are organic compounds with long half-lives that can persist for a very longtime in the environment (Revathi and Jennifer, 2006).
More than 800 compounds appear likely to meet the criteria for the classification asPOPs (Brown and Wania, 2008).
At least 120 of these chemicals are produced in high volumes (1000 tonnes per year)(Brown and Wania, 2008).
Stockholm Convention on POPs came into force in 2004 and aim to protect humansand environment from POPs (Xu et al., 2013).
10
POPs listed in Stockholm Convention amendment (Xu et al., 2013)
2001 amendment 2009 amendment 2011 amendment
Aldrin Chlordecone (Kepone) Endosulfan
Dieldrin Lindane
Endrin α- HCH
Chlordane Β- HCH
Heptachlor Hexabromobiphenyl
HCB Tetra-BDE and penta-BDE
Mirex Hexa-BDE and hepta-BDE
Toxaphene PFOs and its salts
PFOSF
DDT Pentachlorobenzene
PCBs
PCDDs and PCDFs
11
Pesticide
Industrial
By-product
POPs Status
Aldrin Registration expired in 1994
Chlordane Registration expired in 1997
Dieldrin Registration expired in 1994
DDT Registration expired in 1999
Endrin Never registered
Hexachlorobenzene Never registered
Mirex Never registered
Toxaphene Never registered
14
Status of POPs in Malaysia
(Source: Consumers’ Association of Penang, 2005; Revathi and Jennifer, 2006)
Maximum concentration limit in Class IIA standard for pesticide levels in Malaysian river water suitable as water supply
Pesticides
Maximum pesticide
concentration limit
Lindane 2 µgl-1
Heptachlor 50 ngl-1
Endosulfan 10 µgl-1
Total DDTs 100 ngl-1
Dieldrin 20 ngl-1
15
(Source: Leong et al., 2007)
Overview of POPs dispersion in the environment of air, water and biosphere
16
(Source: Langenbach, 2013)
Mechanism of POPs Degradation
Example:
Chemical stability: DDT degrades to DDE
DDE is less toxic than DDT but more resilient in the environment
18
Sources of POPsSources of POPs
Agricultural area
Rice Paddy
Vegetable farm
Landfill
Consumer products
Process
Industrial
Chemical
Thermal
19
Effects of POPs on wildlife/ humans
Cancers
Birth defect
Dysfunctional immune, development and reproductive systems
Fertility problems
Disease susceptibility
Diminished intelligence
20
Challenges in POPs ManagementOver the last decades, organochlorine pesticides were found extensively in used
(Sani, 2007).
About 253,989 kg of DDT had been applied as insecticide residual spray between
1991 to 1998 in Malaysia (Sani, 2007).
The total volume of leachate generated from landfills in Malaysia is estimated at
approximately 3.0 million liters per day (Agamuthu,2001).
In Malaysia, non-pesticide source of POPs are not well monitored (Roland et al.,
2011).
Methods such as coagulation, precipitation, and reverse osmosis have been
found to be limited for POPs removal (Rashed, 2013).
21
Challenges in POPs ManagementVery slow progress with the destruction of POPs pesticides and polychlorinated biphenyl (PCB) stockpiles
Exports of POPs in waste and products from industrial countries
Most ‘remediation’ undertaken to date involves containment rather than the ‘destruction or irreversible transformation’
Leaves pollutants for future generations to manage and is not consistent with sustainable development
Continued use of POPs such as DDT can therefore be of lowest financial cost to the original consumer
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Characteristics of Leachate Samples from Selected Landfills in Malaysia
23
JSL- Jeram Sanitary
Landfill
PBSL- Pulau Burung
Sanitary Landfill
BTSL- Bukit Tagar
Sanitary Landfill
Leachate Treatment Methods
• Aerobic Treatment
• Anaerobic Treatment
Biological Treatment
• Floatation
• Coagulation
• Adsorption
• Membrane Filtration
Physical/Chemical Treatment
24
Aerobic Treatment Suspended Growth Systems
Lagoons
Activated Sludge Processes
Sequencing Batch Reactors
Attached Growth Systems
Trickling Filters
Moving Bed Biofilm Reactors
25
Anaerobic TreatmentSuspended Growth Systems Attached Growth Systems
Digesters (UASB, EGSB,DSF) Anaerobic Filter
Hybrid Bed Filter
26
CoagulationAdvantages
Aluminum sulfate, Ferrous sulfate, Ferric chloride and Ferric chloro-sulfate are commonly used coagulants.
Effective for organic compounds and heavy metals.
Disadvantages
Consistent sludge volume is produces
Increase in concentration of Aluminum or Iron, in the liquid phase, ,may be observed
High pH has to be maintained
28
AdsorptionAdvantages
Design and operating adsorption columns are easy
Availability materials which can be used as adsorbents(coconut shells, charcoal, zeolite, incinerator ash)
High removal efficiency of > 90% COD
Disadvantages
Constant regeneration of activated carbon
Disposal of used carbon
Cost of GAC & PAC
29
Disadvantages in using Alum
Aluminium sulphate (alum) is a commonly used inorganic salt for treating wastewater.
Alum is chosen for treating POPs due to
- Low cost
- Easily available (Renault et al., 2009)
However, alum is not environmental friendly as it produces large amount of sludge and possible to be toxic.
The effectiveness of alum is highly dependent on pH and the flocs are not very mechanically resistant when formed in cold water (Renault et al., 2009).
31
What is Green Coagulant? Green coagulant is natural coagulant that is commonly used in water treatment due to its relatively cost-effective compared to chemical coagulants, can be easily processed in usable form and biodegradable.
32
Example of Green Coagulants Source
Guar gum Seed of the guar plant (Cyamopsis
tetragonoloba).
Xanthan gum Strain of bacteria used during the
fermentation process, Xanthomonas
campestris
Locust bean gum Seed of the carob tree
Role of Green Technology
Natural coagulants are better options as compared to chemical coagulants in treating POPs due to
- Minimal coagulant dosage requirement
- Efficiency at low temperature
- Produce small volume of sludge
Chemical coagulants are generally more expensive, toxic and with low biodegradability (Verma et al, 2012).
33
35
Results and DiscussionPercentage of POPs removal in leachate using Guar Gum and Alum, at pH12 at
various dosage.
To remove more than 80% of
POPs in leachate, 4.0 mg/L of
Guar gum or 0.5g/L of alum is
used.
This indicated that 125 times
much higher concentration of
alum is needed as compared
to Guar gum to effectively
remove POPs in leachate.
36
Results and DiscussionResponse surface plot for pyridine,3-(1-methyl-2-pyrrolidinyl) and
bis(2-ethylhexyl) phthalate removal by Guar Gum addition
Design-Expert® Software
Pyridine,3-(1-methyl-2-pyrrolidinyl) removal99
47
X1 = A: pHX2 = B: Guar Gum Dose
Actual FactorC: Mixing speed = 200.00
4
6
8
10
12
3.00
3.50
4.00
4.50
5.00
47
59
71
83
95
P
yri
din
e,3
-(1
-me
thyl-
2-p
yrr
olid
inyl)
re
mo
va
l
A: pH B: Guar Gum Dose
Design-Expert® Software
Bis(2-ethylhexyl) phthalate removal99
31
X1 = A: pHX2 = B: Guar Gum Dose
Actual FactorC: Mixing speed = 200.00
4
6
8
10
12
3.00
3.50
4.00
4.50
5.00
31
44.25
57.5
70.75
84
B
is(2
-eth
ylh
exyl)
ph
tha
late
re
mo
va
l
A: pH B: Guar Gum Dose
When the Guar gum is added in low concentration, it attached to the colloidal particles by
forming bridge which enable the removal of POPS in leachate
When Guar gum was added in excess, there is insufficient particles surface for the biopolymer
attachment (Tripathy & De, 2006)
37
Results and DiscussionSEM and FTIR Analysis
Guar gum flocs had porous,
cross linkage and amorphous
surface structure as compared
to alum
The free reactive hydroxyl
groups in the Guar gum
backbone was substituted by
different functional groups
which enable the removal of
POPs
POPs Removal Using Xanthan Gum
38
2.5 mg/l of Xanthan Gum3.0 mg/l of Xanthan Gum4.0 mg/l of Xanthan Gum5.0 mg/l of Xanthan Gum
Role of Green Technology
Recent studies found that 85.91% and 94.08% of bis(2-ethylhexyl) phthalate were effectively removed from leachate using Guar gum and Xanthan gum, respectively at pH12.
Polymer bridging by green coagulant was responsible for POPs removal
Removal of POPs by alum was less efficient as compared to green coagulant.
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ConclusionThere is a growing concern on ecotoxicological impacts of landfill leachate and its treatment .
POPs which are commonly found in landfill leachate are potentially hazardous to living organism because of their higher degree of halogenations, inclination to bioaccumulate in the lipid component and their resistance to natural degradation.
To address the threat posed by widespread POPs contamination, remediation technologies continue to be developed to treat these pollutants.
Natural coagulant such as Guar gum and Xanthan gum were very effective in treating POPs and are highly recommended as an option for treating POPs because it is a biodegradable biopolymer, non-toxic, involved low treatment cost, easily available and is produced in abundance.
40
Acknowledgement• Ministry of Higher Education (MOHE) for providing the Fundamental Research Grant
Scheme (FRGS) (Project No: FP052-2013B)
• University of Malaya, Kuala Lumpur for Postgraduate Research Fund (PPP) (Project No: PO008-2014A)
41
References-1
Agamuthu, P. (2001). Solid waste: principles and management with Malaysian case studies. KualaLumpur, Malaysia: University of Malaya Press.
Brown, T. N., & Wania, F. (2008). Screening chemicals for the potential to be persistent organicpollutants: a case study of Arctic contaminants. Environ Sci Technol, 42(14), 5202-5209.
Kee, Y. L., Mukherjee, S., & Pariatamby, A. (2015). Effective remediation of phenol,2,4-bis(1,1-dimethylethyl) and bis(2-ethylhexyl) phthalate in farm effluent using Guar gum – A plant basedbiopolymer. Chemosphere, 136, 111-117.
Megharaj, M., Ramakrishnan, B., Venkateswarlu, K., Sethunathan, N., & Naidu, R. (2011).Bioremediation approaches for organic pollutants: A critical perspective. Environment International,37(8), 1362-1375.
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References-2Rashed, M. N. (Ed.). (2013). Adsorption technique for the removal of organic pollutants from water andwastewater. doi: 10.5772/54048
Revathi, R. & Jennifer, M. (2006). Overview of the POPs pesticide situation in Malaysia. International POPsElimination Project, Penang, Malaysia.
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Verma, A. K., Dash, R. R., & Bhunia, P. (2012). A review on chemical coagulation/flocculation technologies forremoval of colour from textile wastewaters. Journal of Environmental Management, 93(1), 154-168.
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