Engineered Nanomaterials for Landfill Leachate

37 Engineered Nanomaterials for Landfill Leachate Treatment in the Humid Tropics: The Sri Lankan Perspective Meththika Vithanage,1 S.S.R.M.D.H.R. Wijesekara,1 I.P.L. Jayarathna,1 Anuradha Prakash, 2 Seema Sharma, 2 and Ashok Kumar Ghosh2 Chemical and Environmental Systems Modeling Research Group, Institute of Fundamental Studies, Kandy, Sri Lanka 2 Department of Environmental and Water Management, Anugrah Narayan College, Patna, India 1

CONTENTS 37.1 Introduction......................................................................................................................... 760 37.1.1 Municipal Solid Waste Dumping......................................................................... 760 37.1.2 Characteristics of Landfill Leachate..................................................................... 760 37.1.3 Common Treatment Practices for Landfill Leachate......................................... 761 37.1.4 Nanomaterials in Leachate Treatment................................................................. 762 37.2 Materials and Methods...................................................................................................... 763 37.2.1 Synthesis of Nanoparticles.................................................................................... 763 37.2.1.1 Synthesizing NZVI.................................................................................. 763 37.2.1.2 Synthesis of Iron Oxide Nanoparticles................................................. 764 37.2.1.3 Synthesis of Gibbsite Nanoparticles...................................................... 764 37.2.1.4 Synthesis of Ag Nanoparticles from Bacteria...................................... 764 37.2.2 Chemical Characteristics of Landfill Leachate................................................... 765 37.2.2.1 Treatment of Landfill Leachate.............................................................. 766 37.2.2.2 Synthetic Leachate for Metal Treatment............................................... 766 37.3 Results and Discussion...................................................................................................... 766 37.3.1 Physiochemical Characteristics of Leachate....................................................... 766 37.3.2 Characterization of Nanoparticles....................................................................... 767 37.3.2.1 Starch-Coated NZVI................................................................................ 767 37.3.2.2 Iron Oxide Nanoparticles....................................................................... 767 37.3.2.3 Nanogibbsite............................................................................................. 768 37.3.2.4 Silver Nanoparticles................................................................................ 769 37.3.3 Nutrient Treatment Using Different Nanoparticles.......................................... 770 37.3.4 Phosphate PO 3− Removal by Nanomaterials................................................... 771 4 37.3.5 BOD Removal by Nanomaterials......................................................................... 771 37.3.6 Metal Ion Removal in Synthetic Leachate........................................................... 772 37.3.7 Adsorption Isotherm Studies................................................................................ 773 37.4 Conclusions.......................................................................................................................... 774 References...................................................................................................................................... 774

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Aquananotechnology: Global Prospects

37.1 Introduction 37.1.1 Municipal Solid Waste Dumping Municipal solid waste (MSW) management is a major environmental problem in many countries worldwide [1]. Globally, hundreds of megatons of waste is generated each year (i.e., MT/ year >108) and MSW is a dominant stream that contributes a significant fraction to the total content of waste [2]. Most countries worldwide practice different waste management methods; several are with successful stories, and some are poorly designed or poorly managed with demerits [3]. Developed countries use advanced MSW management methods such as waste incineration and bioelectricity for generation of electricity instead of conventional waste management methods [4,5]. The management of waste has become a critical concern for most of the developing countries because of the absence of appropriate waste management methods [6]. However, only a few local bodies and some institutes in developing countries are practicing composting, anaerobic digestion, and valuable materials recovery using MSW as solutions instead of open dumping and burning of waste [7,8]. On the other hand, population increments with rapid urbanization, industrialization, and modernization as way of life are generating more waste content that is complex in nature. Mainly, MSW is the major fraction for the total waste content that comprises biodegradable material, plastics, metals, construction and demolition waste, electronic and hazardous waste, etc. However, it is difficult to categorize the different types of waste because of their complex characteristics and disposal procedures. Most of the Asian countries practice open dumping and nonengineered disposal of waste since it is easy and cheap [1]. Sri Lanka’s commercial city, Colombo, in the western province itself has about 60 locations as open dumps that are currently being maintained by the local authorities, well an example of this situation [9]. Furthermore, recent studies have revealed that MSW of about 3700 tons is being generated each day in Sri Lanka [10]. One of the most critical aspects associated with open dump sites is the formation of leachate, which is well understood as a typical contaminant containing a large amount of pollutants [11]. The higher biodegradable fraction or organic content that is typically disposed in large content in Sri Lankan dump sites may raise many issues due to the formation and direct discharge of highly polluted leachate into the environment [12]. Frequently, this complex leachate is released to the nearest water body without any treatment mechanisms. This can lead to much adverse impact on the local soil and water sources [13]. Unfortunately, most of the open dump sites are located close to the water bodies, which even magnify the adverse impacts with an accelerated rate. In addition, the landfill leachate is shown to be highly toxic to higher plants, algae, invertebrates, and fish [14]. Therefore, economically viable, environmentally friendly, and socially acceptable solutions are needed and commissioned for the responsible authorities immediately to overcome landfill leachate–related issues to ensure environmental sustainability. 37.1.2 Characteristics of Landfill Leachate Many countries have identified landfill leachate as a typical contaminant for surface water, groundwater, and soil fertility due to its toxicity [15]. High concentrations of Cd(II), Hg(II), Ni(II), Mn(II), Cu(II), Zn(II), and Pb(II) have been reported associated with leachate, and these metals have been identified as enhancing their transportation with dissolved organic carbon derivatives by anaerobic degradation of organic compounds present in the leachate such as humic, fulvic, and hydrophilic compounds [11,16,17]. Furthermore, inorganic ions

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Nanomaterials for Landfill Leachate Treatment in Sri Lanka

TABLE 37.1 Composition of Acetogenic and Methanogenic Landfill Leachates Values from Literature Acetogenic Leachate

Methanogenic Leachate

a

Parameter

Al-Wabel [1]

Robinson [16]

Hunce [18]

Robinson [16]

pH Conductivity BOD COD Alkalinity Ammonium–nitrogen Nitrate–nitrogen Phosphate Chloride Zinc Cadmium Nickel Chromium Copper Lead

5.9–6.3 6.3–42.5 – 13,900–22,350 – – – –

5.5–7.0 7–30 4000–30,000 10,000–50,000 2000–10,000 750–2000