Unit 5-ENV 243

Unit Overview

  • Focus: Management and removal of emerging contaminants.

Instructor Information

  • Deep Raj, Ph.D.

    • Assistant Professor, Environmental Science and Engineering

    • Email: deepraj.p@srmap.edu.in

Topics Covered

  • Management and removal of emerging contaminants: Overview

  • Physical methods for soil and water

  • Chemical methods for soil and water

  • Bioremediation and phytoremediation approaches

  • Hybrid treatment methods

  • Bio-accumulation effects on ecosystems

  • Trophic transfer in aquatic and terrestrial ecosystems

Overview of Emerging Contaminants

  • Emerging contaminants pose health risks due to:

    • Pharmaceuticals, cosmetics, surfactants, pesticides, fertilizers.

    • Difficulty quantifying trace amounts.

    • Lack of recognition in legislation.

    • Traditional wastewater treatment plants inadequate for removal.

Physical Methods for Soil Contaminants

Adsorption

  • Defined as adhesion of substances to surfaces.

  • Efficient for separating contaminants and enabling recycling of adsorbents (e.g. zeolites, activated carbon, biochar).

Containment Methods

  • Sealing or encapsulation to prevent pollution spread.

Sorption and Stabilization

  • Techniques to immobilize contaminants in soil, preventing leaching.

  • Different sorbents (activated carbon, resins) used.

Thermal Treatment

  • Chemical destruction using heat (500-600 ºC) to vaporize contaminants.

Ball Milling

  • Milling soil with steel balls to reduce particle size and enhance reactions.

Soil Washing

  • Excavation and treatment using water to remove contaminants.

Physical Methods for Water Contaminants

  • Growing concern over water pollution and need for sustainable methods.

  • Techniques: adsorption, advanced oxidation, biodegradation, membrane filtration.

  • Hybrid systems show promise for effectiveness.

Adsorption Techniques

  • Inclusion of various adsorbents optimized for efficiency (biochar, carbon nanomaterials, graphene).

Chemical Methods for Soil Contaminants

Chemical Oxidation

  • Utilizes reactive chemicals to convert contaminants into less harmful substances.

Electron Beam Technology

  • Advanced oxidation through high-energy electron exposure.

Chemical Methods for Water Contaminants

Coagulation and Flocculation

  • Coagulants destabilize particles for removal.

  • Commonly used in textile industries for dye removal.

Bioremediation Approaches

  • Uses natural processes and biological agents for pollutant degradation (microbial, phytoremediation).

  • Effective methods to transform contaminants into non-toxic compounds.

Key Mechanisms

Phytoremediation

  • Utilizes plants to remove or transform contaminants.

  • Efficiency influenced by plant species selection.

Hybrid Treatment Methods

  • Combines multiple techniques for enhanced efficiency in contaminants removal.

Bioaccumulation and Trophic Transfer

  • Understanding contaminant buildup in organisms via bioaccumulation is crucial.

  • Relevant for assessing ecological health and human health risks.

  • Accumulation in crops and livestock can impact food chains and human exposure.

Conclusion

  • Importance of monitoring and appropriate mitigation measures to minimize the impact of emerging contaminants.