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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

  • What Is A Landfill?

    2

  • 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 contd

    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 - HCH

    Chlordane - 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

  • Chemical Structures of POPs

    12

  • Chemical Structures of POPs

    13

  • 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 gl-1

    Heptachlor 50 ngl-1

    Endosulfan 10 gl-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

    17

  • 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

    22

  • 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

  • Floatation

    27

  • 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

  • Membrane Filtration

    30

  • 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 sma

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