Microorganisms In The Environment And Waste Water Treatment Plant

Environmental Microorganisms

Environmental Engineering Lab 레 넉 투안

Contents

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General classification

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Applications of Microorganisms to environmental treatment

Microorganisms in the surface waters and wastewaters

Overview: Classification

Classification by molecular and cellular relationships: Bacteria Archaea

Prokaryote

Eukarya

Eukaryote

Phylogenetic tree of life

Cell structure

Internal structure of microbial cells. (a) Diagram of a prokaryote. (b) Diagram of a eukaryote.

Nucleic acids

Base-pairing in DNA

Double helix structure of DNA

Microorganisms in their natural environment

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They don’t live in pure cultures. They live in communities.

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Their activities can greatly affect (change) the chemical and physical properties of their habitats, e.g. the removal of nutrients and the excretion of waste products.

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Populations in microbial communities can interact in various ways -harmful and/or beneficial.

Role of microorganisms in geochemical nutrient cycles

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Microorganisms play a role as: •PRIMARY PRODUCERS •BIODEGRADERS AND CONSUMERS Critical role in cycles of many elements; • Carbon and and Oxygen cycle • Nitrogen cycle • Sulfur cycle • Phosphorus cycle

How do they grow: requirements?

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Nutrients Carbon, Nitrogen, Phosphorus, Sulfur Many chemicals supply these Micronutrients/ trace metals/ vitamins Electron acceptors - usually O2 Converts / burns carbon substrate to CO2 Energy and biomass * GROWTH

Wastewater treatment: Wastewater treatment: principles

O2 consumption

GROWTH - CELL DIVISION INCREASE IN BIOMASS

2.0µm

ORGANIC POLLUTANT AND NUTRIENTS (C,P,N,O,Fe,S……) SINGLE BACTERIUM

Controlled release of energy Slow Burning!

CO2 evolved

Somes microorganisms found in natural waters, wastewaters, and wastewater treatment processes

Bacteria

Algae

Archaea

Fungi

Protozoa

Virus

Pathogens and parasites found in domestic wastewater The three categories of pathogens encountered in the environment are (Leclerc et al., 2002):

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Bacterial pathogens: Some of these pathogens (e.g., Salmonella, Shigella) are enteric bacteria. Others (e.g., Legionella, Mycobacterium avium, Aeromonas) are indigenous aquatic bacteria.

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Viral pathogens: These are also released into aquatic environments but are unable to multiply outside their host cells. Their infective dose is generally lower than for bacterial pathogens.

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Protozoan parasites: These are released into aquatic environments as cysts or oocysts, which are quite resistant to environmental stress and to disinfection, and do not multiply outside their hosts. Eg: Giardia lamblia Balantidium coli…

Indicator microorganisms The total coliform: group belongs to the family enterobacteriaceae and includes the aerobic and facultative anaerobic, gram-negative, nonsporeforming, rod-shaped bacteria that ferment lactose with gas production within 48 hours at 35C. This group includes Escherichia coli, Enterobacter, Klebsiella, and Citrobacter. These coliforms are discharged in high numbers in human and animal feces, but not all of them are of fecal origin. Fecal Coliforms: Fecal coliforms or thermotolerant coliforms include all coliforms that can ferment lactose at 44.5oC. The fecal coliform group comprises bacteria such as Escherichia coli or Klebsiella pneumonae. The presence of fecal coliforms indicates the presence of fecal material from warmblooded animals. Escherichia Coli: Several strains of E. coli, many of which are harmless, are found in the gastrointestinal tract of humans and warm-blooded animals. There are several categories of E. coli strains, however, that bear virulence factors and cause diarrhea.

Rivers: problems for surface water resource

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Water quality can be impaired by natural elements normally found in soil and rock. These natural elements can be considered contaminates that can harm humans: - Metals: arsenic, mercury and lead - Turbidity: suspended particles of clay soil - Microorganisms: parasites, bacteria, protozoa and toxic blue-green algae.

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Faecal matter from confined animal facilities and feedlots, as well as from animals walking or defecting in streams, can contaminate water with bacteria such as E. coli or microbial pathogens (Cryptosporidium)

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Factory farming of hogs or cattle, where liquid waste is deliberately forced into the ground through boreholes can lead to water contamination.

Municipal wastewater effluents.

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Municipal wastewater effluents or sewage treatment plants are designed to treat waste that is discharged by residents, businesses and industries.

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The quality of water that leaves a treatment plant depends on a variety of factors, such as the type and efficiency of the treatment and disinfection processes used, as well as the quantity and types of wastes received.

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Since treatment processes differ so greatly, municipal wastewater effluents can consist of residues of human waste, solids and debris, nutrients, pathogens, toxics, endocrine disrupting substances, unmetabolized pharmaceuticals, ingredients from household and personal care products, and potentially toxic chemicals and contaminants.

Eutrophication of Surface Waters.c Natural process in which surface waters receive inputs of nitrates and phosphates resulting in overnourishment of aquatic ecosystems (Algae bloom, anaerobic surface water)

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Phosphorus is a key of nutrient responsible for eutrophication

The bright green colour results from bluegreen algae (Cyanobacteria), which are growing on phosphorus added to the near side of the curtain

Microorganisms and Nitrogen •

Nitrogen fixation

Microorganisms and Nitrogen… •

Nitrogen assimilation

Cells convert NO3 or NH4 to proteins and grow until nitrogen becomes limiting. For each 100 units of carbon assimilated, cells need approximately 10 units of nitrogen (C/N ratio = 10). •

Nitrogen Mineralization

Nitrogen removal

Nitrosomonas, nitrobacter

Phosphorus (P) •

Organic phosphorus: foodstuff, toilet wastes, animal wastes…;

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Orthophosphate (PO4-P): fertilizer, products of phosphorus mineralization;

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Polyphosphate: detergents.

Phosphorus removal

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Chemical precipitation, which is controlled by pH and cations such as Ca, Fe and Al… Problems: saturation, clogging.

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Biological phosphorus removal •

Phosphorus assimilation by wastewater microorganisms;

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Enhanced biological phosphorus removal (EBPR);

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Microorganism-mediated enhanced chemical precipitation.

Enhanced biological phosphorus removal (EBPR)

Several microorganisms, called poly P bacteria or polyphosphate accumulating organisms (PAOs), have the ability to accumulate phosphorus in excess of the normal cell requirement, which is around 1–3 percent of the cell dry weight. (eg., Acinetobacter, Pseudomonas,

Aeromonas, Moraxella, Klebsiella, Enterobacter, Tetrasphaera spp.) Pi release and uptake by a laboratory anaerobic–aerobic activated sludge. From Hiraishi et al. (1989).

Enhanced biological phosphorus removal (EBPR)… Polyhydroxyalkanotes (PHAs) are biodegradable polymers synthesized by a number of microorganisms when the essential growth nutrients is limited. -

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Under the anaerobic condition, PAO uptake Volatile fatty acids (VFAs) mainly acetate and stored in side the cells as PHA. The energy for this process is obtained form degradation of polyphosphate (polyP) and glysosis of glycogen. The degradation of poly P results in the release orthophosphate in the liquid. Under the aerobic zone, in the absence of any organic compounds, PHA is metabolized producing energy and carbon sources. The energy is used by PAOs to uptake orthophosphate in order to recover and increase the polyP pool in the cell and to form glycogen

Volatide Fatty Acid (acetate…) PHA Anaerobic condition

Glycogen P + AT Poly P TCA cycle

o-PO4 Aerobic condition

Poly P

Glycogen P AT

PHA CO2 + H2O O2 Biochemical model (Mino et al., 1987)

Cell growth

Enhanced biological phosphorus removal (EBPR)…

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Glycogen accumulating organisms (GAOs), are also part of the EBPR microbial assemblages. (e.g., Candidatus, Competibacter, phosphatis). Although GAOs carry out carbon transformations similar to those of PAOs, they do not take up or release phosphorus (Blackall et al., 2002).

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For the successful operation of the EBPR process one must create conditions for the predominance of PAOs over GAOs. One such condition is the operation of the EBPR process at pH higher than 7 (Filipe et al., 2001) since GAOs predominate at lower pHs. Low temperature is another factor controlling the predominance of PAOs over GAOs. The psychrophilic PAOs are generally favored at low temperatures, leading to an increase in EBPR efficiency (Erdal et al., 2003).

Biological waste-water treatment: The activated sludge process.

Sludge Microbiology

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Bacteria: Zooglea, Pseudomonas, Flavobacterium, Alcaligenes, Achromobacter, Corynebacterium, Comomonas, Brevibacterium, Acinetobacter, Bacillus…

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Fungi: Geotrichum, Penicillium, Cephalosporium, Cladosporium, and Alternaria… Protozoa: Aequorea victoria, Aspidisca costata, Cryptosporium…

Products from Microorganisms: Overview of range of examples. •

Various foods and drinks

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Enzymes for varied uses (GM enzymes); biocatalysts

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Engineered proteins ( antibodies )

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Vaccines and antibiotics (secondary metabolites)

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Primary metabolites and bulk chemicals (amino acids (glutamic acid) and organic acids (acetic acid)

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Pharmaceuticals and novel chiral chemicals

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Recovery of metals in bioleaching

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Biosensors (use of enzymes to specifically detect chemicals in medical)

Thank you for your attention!