Introduction to Environmental Engineering Dr. Kagan ERYURUK

2 Microbial Groups

3 Importance of Microbiology in Environmental Engineering Microbiology; a branch of biology devoted to the study of microorganisms (microbes). Microbiology; a branch of biology devoted to the study of microorganisms (microbes). The objects of this science; the engineering systems of water, wastewater, solid wastes, soil and gas biotreatment. The objects of this science; the engineering systems of water, wastewater, solid wastes, soil and gas biotreatment.

4 1. Bacteria As decomposers – indispensable ecological role by decaying organic matter As decomposers – indispensable ecological role by decaying organic matter Natural processes are enhanced and accelerated in stabilizing organic wastes in treatment plants Natural processes are enhanced and accelerated in stabilizing organic wastes in treatment plants

5 Reproduction and Spores Bacterial reproduction; by binary fission – From one cell 2 new cells. Bacterial reproduction; by binary fission – From one cell 2 new cells. Each then divide again. Approx. every 15 – 30 mins. (doubling time) Each then divide again. Approx. every 15 – 30 mins. (doubling time) Survival mechanism -Some species form spores with tough coatings that are resistant to heat, lack of moisture, and loss of food supply. Survival mechanism -Some species form spores with tough coatings that are resistant to heat, lack of moisture, and loss of food supply. genbio/mitosisnot.html

6 Coliform Bacteria A commonly used bacterial indicator of sanitary quality of foods and water. Total coliform bacteria - commonly found in the environment (e.g., soil or vegetation). Generally harmless. They indicate the presence of organic material. Total coliform bacteria - commonly found in the environment (e.g., soil or vegetation). Generally harmless. They indicate the presence of organic material. Fecal coliform bacteria- a sub-group of the total coliform group. Present in large quantities in the intestines and feces of humans and other and animals. Fecal coliform bacteria- a sub-group of the total coliform group. Present in large quantities in the intestines and feces of humans and other and animals. Escherichia coli - a sub-group of the fecal coliform group. Most E. coli are harmless and are found in large quantities in the intestines of humans and warm-blooded animals. Some strains, however, may cause illness. (E.g. E. coli O157:H7) Escherichia coli - a sub-group of the fecal coliform group. Most E. coli are harmless and are found in large quantities in the intestines of humans and warm-blooded animals. Some strains, however, may cause illness. (E.g. E. coli O157:H7) All are used as a common indicator of the bacteriological quality of water. All are used as a common indicator of the bacteriological quality of water. whatisec.htm wqm.igsb.uiowa.edu/.../ faqsbeachenvironprof.htm E. coli

7 Heterotrophic and Autotrophic Bacteria Bacteria can be classified into 2 main groups depending on their source of nutrients: Heterotrophs use organic matter as both an energy and a carbon source for synthesis. They are further sub-divided into 3 groups depending on their action toward free oxygen Heterotrophs use organic matter as both an energy and a carbon source for synthesis. They are further sub-divided into 3 groups depending on their action toward free oxygen –Aerobes –Anaerobes –Facultative Autotrophs oxidize inorganic compounds for energy and use carbon dioxide as a carbon source Autotrophs oxidize inorganic compounds for energy and use carbon dioxide as a carbon source

8Heterotrophs Aerobes require free dissolved oxygen in decomposing organic matter to gain energy for growth and multiplication. Found in activated sludge and trickling filters in wastewater treatment. Aerobes require free dissolved oxygen in decomposing organic matter to gain energy for growth and multiplication. Found in activated sludge and trickling filters in wastewater treatment. Anaerobes oxidize organics in the complete absence of dissolved oxygen by using oxygen bound in other compounds (such as nitrate and sulfate). They predominate in sludge digestion. Anaerobes oxidize organics in the complete absence of dissolved oxygen by using oxygen bound in other compounds (such as nitrate and sulfate). They predominate in sludge digestion. Facultative bacteria compose a group that uses free dissolved oxygen when available but can also live in its absence by gaining energy from anaerobic reaction. They are active in both aerobic and anaerobic treatment units. Facultative bacteria compose a group that uses free dissolved oxygen when available but can also live in its absence by gaining energy from anaerobic reaction. They are active in both aerobic and anaerobic treatment units.

9Autotrophs Oxidize inorganic compounds for energy and use carbon dioxide as a carbon source. Oxidize inorganic compounds for energy and use carbon dioxide as a carbon source. Nitrifying, sulfur, and iron bacteria are of greatest significance. Nitrifying, sulfur, and iron bacteria are of greatest significance. Nitrifying bacteria oxidize ammonium nitrogen to nitrate. Nitrification can occur in biological secondary treatment under the conditions of low organic loading and warm temperatures (often avoided to reduce oxygen consumption in treatment and to prevent floating sludge on the final clarifier). Nitrifying bacteria oxidize ammonium nitrogen to nitrate. Nitrification can occur in biological secondary treatment under the conditions of low organic loading and warm temperatures (often avoided to reduce oxygen consumption in treatment and to prevent floating sludge on the final clarifier). Iron bacteria can flourish in some pipes (more of a problem for water delivery pipes). Iron bacteria can flourish in some pipes (more of a problem for water delivery pipes).

10 2. FUNGI Microscopic non photosynthetic plants including yeasts and molds Microscopic non photosynthetic plants including yeasts and molds Molds are aerobic and grow best in acid solutions high in sugar content Molds are aerobic and grow best in acid solutions high in sugar content Fungi are found in wastewater in small numbers but if there is large increase in fungi concentration it is an indication of a change in pH of the activated sludge. Fungi are found in wastewater in small numbers but if there is large increase in fungi concentration it is an indication of a change in pH of the activated sludge.

11 Protozoa and Multicellular Animals Protozoa- single-celled aquatic animals that multiply by binary fission. They have complex digestive systems and use solid organic matter as food. Protozoa- single-celled aquatic animals that multiply by binary fission. They have complex digestive systems and use solid organic matter as food. Protozoa are aerobic organisms found in activated sludge, trickling filters, and oxidation ponds treating wastewater. Protozoa are aerobic organisms found in activated sludge, trickling filters, and oxidation ponds treating wastewater.

12 Viruses Viruses are obligate, intracellular parasites that replicate in living hosts’ cells (i.e. not involved in the digestion of wastewater) Viruses are obligate, intracellular parasites that replicate in living hosts’ cells (i.e. not involved in the digestion of wastewater) They may be involved in infecting bacterium, but their real relevance to wastewater treatment is in terms of infection of humans They may be involved in infecting bacterium, but their real relevance to wastewater treatment is in terms of infection of humans

13 Algae Algae are microscopic photosynthetic plants of the simplest form. Algae are microscopic photosynthetic plants of the simplest form. Their relevance to most wastewater processes is in terms of their control in the processes and at the end of the pipe. Their relevance to most wastewater processes is in terms of their control in the processes and at the end of the pipe. Wastewater stabilization ponds support luxurious blooms of algae to the point where the suspension becomes self-shading. Wastewater stabilization ponds support luxurious blooms of algae to the point where the suspension becomes self-shading.

14 Bacterial Growth Requirements 1. Terminal electron acceptor 2. Macronutrients a. carbon b. nitrogen c. phosphorus 3. Micronutrients a. trace metals b. vitamins 4. Environment a. moisture b. temperature c. pH

15 Growth in Pure Cultures

During lag phase, bacteria adapt themselves to growth conditions. It is the period where the individual bacteria are maturing and not yet able to divide. During lag phase, bacteria adapt themselves to growth conditions. It is the period where the individual bacteria are maturing and not yet able to divide. The log phase is a period characterized by cell doubling. The number of new bacteria appearing per unit time is proportional to the present population. The log phase is a period characterized by cell doubling. The number of new bacteria appearing per unit time is proportional to the present population. The stationary phase is often due to a growth-limiting factor such as the depletion of an essential nutrient, and/or the formation of an inhibitory product such as an organic acid. The stationary phase is often due to a growth-limiting factor such as the depletion of an essential nutrient, and/or the formation of an inhibitory product such as an organic acid. At death phase (decline phase), bacteria die. This could be due to lack of nutrients, a temperature which is too high or low, or the wrong living conditions. At death phase (decline phase), bacteria die. This could be due to lack of nutrients, a temperature which is too high or low, or the wrong living conditions. 16

17 Mathematics of Growth log growth phase log growth phase

18 Example Bread yeast cells divide and form 2 cells every 5 minutes. If you place 10 5 cells in a suitable environment, how many cells will you have in 30 minutes? Bread yeast cells divide and form 2 cells every 5 minutes. If you place 10 5 cells in a suitable environment, how many cells will you have in 30 minutes?

19 Mixed Cultures Pure cultures do not exist in nature Pure cultures do not exist in nature Log growth may occur when one organism or group has few external limits Log growth may occur when one organism or group has few external limits Most organisms interact with other organisms: Most organisms interact with other organisms: –competition for food and other resources –inhibitor