Biological Remediation of Land and Water

Naz Mina MertZuhal Ozcan Inanc PastirmaciOya Tekbulut

Outline

1. Land pollution2. Bioremediation of land3. Water pollution4. Bioremediation of water

Bioremediation of Land

What is bioremediation?

• The process of cleaning up contaminated sites using microorganisms to remove or degrade toxic wastes and other pollutants from the environment.

• Bioremediation can occur naturally or can be encourage with addition of microbes and fertilizers.

• Ex Situ:the removal of the contaminated material to be treated elsewhere.

• In Situ: treating the contaminated material at the site.

• Dominantly used organisms:–Bacteria (anearobic and aerobic)–Fungi

Suitable conditions for bioremediation

• Sufficiently large bacteria population• Presence of electron acceptors• Presence of nutrients (nitrogen and

phosphorus)• Chemicals not toxic for bacteria • Sufficient source of carbon for bacterial

growth

Bioremediation techniques:

Land Farming• Ex Situ• Contaminated soil is spread over a prepared

bed along with some fertilizers and occasionally rotated.

• It stimulates the activity of bacteria and enhances the degradation of oil.

Composting

• Ex Situ• Piling of contaminated soil organic substances

such as agricultural wastes

• Development of a rich microbial population.

• Increase in temperature of the pile. Stimulation of microbial growth by added nutrients.

• Eventually biodegredation.

Bioventing

• In situ remediation technology.• Adding of oxygen in unsaturated zone by

pressing.

Biopiling

• Ex situ version of soil bioventing.• Soil is mixed with additives and placed onto

suitable site.• Ventilation device is installed during piling.

Phytoremediation

• Plants and trees are planted.• Their roots absorb contaminants from

groundwater over time, and are harvested and destroyed.

• For ex: cottonwood for Hg

Biostimulation• In situ• modification of the environment to stimulate

existing bacteria.• the process of adding nutrient, electron

acceptor and oxygen to stimulate. • Additives are usually added to the subsurface

through injection wells.

Bioaugmentation• In situ• The addition of a group of indigenous

microbes or genetically engineered microbes to treat the contaminated soil.

Bioremediation of Heavy Metals

• Works through the adsorption of metal molecules to bacterial cells.

• Transformation to nontoxic compounds (CO2 and H2O) is not possible.

• Transformation to less toxic compounds occur.

Question:What are the suitable conditions for bioremediation?

• Sufficiently large bacteria population• Presence of electron acceptors• Presence of nutrients (nitrogen and

phosphorus)• Chemicals not toxic for bacteria • Sufficient source of carbon for bacterial

growth

Water Pollution

What is water pollution?

• a global problem• Varies in magnitude and type of pollutant• Developing countries

– lack of disease-free drinking water

Eight categories of water pollution

• Sewage• Disease-causing agents• Sediment pollution• Inorganic plant and algal nutrients• Organic compounds• Inorganic chemicals• Radioactive substances• Thermal Pollution

Sewage

• The release of sewage into water results in several pollution problems. 1. Because of the disease-causing agents in it, sewage poses

a threat to public health. 2. Enrichment: the fertilization of water due to the presence

of high levels of plants and algal nutrients, i.e. nitrogen and phosphorus.

– Cellular respiration requires the presence of oxygen , fishes and other organisms also use oxygen. In aquatic ecosystems containing high levels of sewage, decomposition of microorganisms use up most of the dissolving oxygen, leaving little for aquatic animals. -> Fishes and other animals die or migrate if condition is harsh

Sewage (cont’d)3. Another serious environmental problem that sewage generates is oxygen demand. Organic wastes including sewage are measured in terms of their biological oxygen demand and it is expressed as milligrams of dissolved oxygen per liter of water. A large amount of sewage produces high BOD which decreases the water of dissolved oxygen and consequently compounds with unpleasant odor are generated, reducing water quality.

Figure 1: The dissolved oxygen in the figure above, directly influences the organisms living inside the river. The curve for BOD (biological oxygen demand) is also present in the above picture.

Disease-causing agents

• Infectious organisms causing diseases – i.e. cholera, infectious hepatitis, typhoid

• Generated from the waste of infected individuals

• Municipal wastewater usually contains many bacteria, viruses, and other agents that lead to diseases

• Rare in highly developed countries, major cause of death in less developed countries

Sediment Pollution

• Sediments are not necessarily pollutants, they are mostly important for providing essential nutrients to wetland areas and in regenerating soils in agricultural areas.

• Sediment pollution occurs when excessive amounts of suspended soil particles settle out and accumulate on the bottom of the water.

• Results from erosion of agricultural lands, strip mines or construction• Reduces light penetration, covers aquatic organisms, brings insoluble

toxic pollutants into the water, and fills in waterways – Reduction in light penetration lessens the ability of producers to

photosynthesize, which might cause a decrease in the number of the organisms

Inorganic Plants and Algal Nutrients

• Inorganic plants and algal nutrients are chemicals such as nitrogen and phosphorus that stimulate the growth of plants and algae

• They are essential for the normal functioning of healthy ecosystems but are harmful in larger concentrations

• Source: animal and human wastes, plant residues, atmospheric deposition

• Encourages excessive growth of plants and algae -> disrupts the balance between producers and consumers

• Bad odor• Encourages enrichment

Organic Compounds

• Organic compounds: contain C atom– i.e. sugars, amino acids, oils

• Found in: water, human-produced chemicals• Some organic compounds seep from landfills

into surface water and groundwater• Some pesticides leach downward though the

soil into the water• Sometimes industries dump organic compounds

directly into waterways

Radioactive Substances

• Contain atoms of unstable isotopes that spontaneously emit radiation

• Reach water through mining and processing of radioactive substances, such as uranium and thorium

• Various industries use radioactive substances and radiation can escape from these facilities and pollute water

Thermal Pollution• Thermal water occurs when heated water produced during

certain industrial processes is released to waterways• Industries use water to remove excess heat from their operations

and then the water is allowed to cool a little and returned to waterways when it is still warm

• Due to the high temperature, the waterway is warmed – Reproductive cycles, digestion rates, and respiration rates of organisms

might change due to the temperature change– Chemical reactions, such as decomposition of wastes, occurs faster,

depleting the water of oxygen– Less oxygen dissolves in warm waterBoth have serious consequences in aquatic life:

- Fishes require more food to maintain body weight, -Shorter life spans, smaller populations

Question

• What can individuals do for prevention of water pollution? Do you believe it would change anything?

Answer

• Although individuals produce little water pollution, the collective effect of municipal water pollution, even in a small neighborhood, can be quite large. Some of the things that individuals can do to protect surface waters and groundwater from pollution:– Drive less. Air pollution emissions from cars eventually get

into water. Also, toxic metals and oil by-products deposited on the road by cars are washed into surface waters by precipitation

– Pick up pet waste and dispose it in the garbage or toilet– Do not throw unwanted medicines down the toilet

Bioremediation of Water

Figure retrieved from http://www.algaeindustrymagazine.com/algal-bioremediation-with-hydroentia

Wastewater Treatment• Removal of human sewage

– Agents stimulating bioremediation of household wastes• Bacteria rich in degrading enzymes

• Wastewater treatment plants– a mudlike material: sludge– flowing water: effluent– Oxidation of organic materilas in the effluent

• Candidatus ‘Brocadia anammoxidans’ degradation of ammonium

Septic-tank disposal systems

Wastewater Treatment

• Wastewater treatment plants– Primary Treatment

• Removes around 30 – 40 % of BOD (v)– Secondary Treatment

• activated sludge recycled– Advanced Wastewater Treatment

• eg. phosphates and nitrates, heavy metals, organic chemicals

• Sand filters, corabon filters• Good water quality

Figure retrieved from Botkin & Keller (2011).

Wastewater Treatment Septic-tank disposal systems

When any central sewage system or wastewater treatment facility is not available

Common problems:

Failure to pump out the septic tank whilst full of

solids

Poor soil drainage

Figure retrieved from Botkin & Keller (2011).

Groundwater Cleanup• Combination of in situ and ex situ techniques

Figure retrieved from Thieman & Palladino (2009).

Figure retrieved from Fingerman, et al. (2005).

Figure retrieved from Fingerman, et al. (2005).

http://www.youtube.com/watch?v=vENEpRUhbms

Figure retrieved from Malik. (2004).

Figure retrieved from Malik. (2004).

Figure retrieved from Malik. (2004).

Figure retrieved from Davis, et al. (2003).

Question: In their research, Romera, et al. (2007) shows that Chondrus crispus, a type of red alga exhibits uptake of various metals from aqueous solutions in different pH values (see the figure below). A scientist would like to propose a strategy for the identification of Chondrus crispus which may play role in degrading an efficient metal within this pH range. What would be the best choice and what can be her strategy ? (Initial conditions are assumed to be kept constant and ideal).

Figure retrieved from Romera, et al. (2007).

Answer: The values suggest that within the range of 4 – 5 (pH), Cu is observed to show the optimum sorption activity. This may be the sign that the cells of the species are capable of the degradation of Cu. Further experiments should be done to check with the biomass capacity of the species and see if it is possible to yield sustainable biosorption activity.

ReferencesBoktin, D. B. & Edward, A. K. (2011). Water pollution and treatment. In Environmental Science, pp. 414-417.

Wiley.

Davis, T. A., et al. (2003). A review of the biochemistry of heavy metal biosorption by brown algae. Journal of

Water Research, 37, 4311-4330.

Fingerman, et al. (2005). Bioremediation of Heavy Metals Using Microorganisms. In Bioremediation of

Aquatic and Terrestrial Ecosystems, pp. 97-100. Science Publishers: Enfeld.

Malik, A. (2004). Metal bioremediation through growing cells. Environment International, 30, 261-278.

Peter H. Raven ,Linda R. Berg, David M. Hassenzahl (2001) Environment

Richard T. Wright, Dorothy F. (2008) Boorse Environmental Science

Romera, E., et al. (2007). Comparative study of biosorption of heavy metals using different types of algae.

Journal of Bioresource Technology, 98, 3344-3353.

Thieman, W.J. & Palladino, M.A. (2009). Bioremediation. In Introduction to Biotechnology, pp. 218-221.

Pearson.

William J. Thieman Micheall, A. Palladino Third Edition Inroduction to Biotechnology

http://www.theinnovationdiaries.com/wp-content/uploads/2011/12/how-does-water-pollution-affect-humans.jpg

http://waterdesalinationplants.com/sewage-treatment/

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