Fifth Lecture 1

7/31/2019 Fifth Lecture 1

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BOD Test15 ml of the waste sample was added directly into a 300ml BODincubation bottle. The initial DO of the diluted sample was8.8mg/L and the final DO after days was 1.9 mg/L. Thecorresponding initial and final DO of the seeded dilution water

was 9.1 and 7.9 respectively. what is the 5 days BOD of the wastewater sample.

BOD5 (mg/L) = (D1 D2) (B1 B2) f

P

= (8.8- 1.9) (9.1- 7.9) 0.950.05

= 115.5mg/L

D1=dissolve oxygen afterpreparationD2= dissolve oxygen after 5 daysincubationB1= organic matter before

incubtionB2= organic matter afterincubtionf= fraction of water volume insample to volume of dilutionP= fraction of waste watervolume to total combined

volume


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These characteristics of waste water are of fundamentalimportance in the control of diseases caused by the

pathogenic organisms of human origin, and because ofthe extensive and fundamental role played by bacteriaand other micro organisms in the decomposition andstabilization of organic matter both nature and in wastewater treatment plant.


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Purpose to study the biological characteristic

Micro organism found in waste water and surface water.

Pathogenic micro organisms associated with human diseases

Use of indicator organisms

Methods and techniques used for the enumeration of bacteria

Methods of enumerate virus


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Role of micro organisms:

The stabilization of organic matter is accomplished biologically

using a variety of micro organisms. The micro organisms convertthe colloidal and dissolved carbonaceous organic matter intovarious gases and protoplasm. Because protoplasm has a specificgravity slightly greater than that of water, it can be removed fromthe treated liquid by gravity settling.

If the protoplasm is not removed the only treatment that will beachieved is that associated with the bacterial conversion of theorganic matter originally present to various gaseous endproducts.


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Eucaryotes: Cells contain membrane bound nucleus andmembranous.

Animals

Plants

Fungi

Protozoa

Procaryotes: No distinct nucleus and no membranous

Bacteria


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Typical micro organism found in waste water and surface water1.Bacteria:Bacteria are single cell prokaryotic organisms. The interior of the cell contains a colloidal suspension ofproteins, carbohydrates and other complex organic compounds called cytoplasm.the cytoplasm containsribonucleic acid(RNA) whose major role is to synthesis of proteins. within cytoplasm deoxyribonucleic(DNA)DNA contains all the information necessary for their growth.

2.Archaea.Found an aerobic process under extreme condition of temperature and chemical composition.

3.Fungi:Fungi have the ability to grow under low moisture, Low nitrogen condition and can tolerate anenvironment with a relatively low pH. The ability of the fungi to survive under low pH nitrogen limitingcondition coupled with their ability to degrade cellulose makes them very important in the composting of

sludge.4.Protoza.Protoza are generally an order of magnitude large than bacteria and often consume bacteria as energysource. Protoza as polisher of the effluents from the biological waste treatment process by consumingbacteria and particulate organic matter.

5.Algae.

In waste water treatment lagoons the ability of algae to produce oxygen by photosynthesis is vital toecology of the water environment.


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BACTERIA PROTOZOA


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FUNGI ALGAE


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2. By energy and carbon source:Carbon is the basic building block for cell synthesis .A source ofenergy must be obtained from outside the cell to enable synthesisto proceed.Our goal in waste water treatment is to convert both the carbon

and the energy in the waste water in the in the cells of microorganisms which we can remove from the water by settling.Therefore we wish to encourage the growth of microorganismsthat use organic material for the both their carbon and energysource.

4. By their Temperature:Each species of bacteria reproduces best within a limited range oftemperature.


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Psychrophiles:Grow best at temperature below 20CMesophiles:

Grow best at temperature between 25 - 40CThermophiles:Grow best at temperature 45 - 60CStenthermophiles:

Grow best above 60C


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.

The anaerobic decomposition of OM generally is consideredto be two step process. In the first step complex organiccompounds are fermented to low molecular weight fatty

acids (volatile acids).In second step the organic acids areconverted to methane.Co2 served as the electron acceptor.

Direct an aerobic decomposition of waste water generally is

not feasible for dilute waste. the optimum growthtemperature for the anerobic bacteria is at the upper end ofthe mesophilic range.

BOD level grater than 1000mg/l an aerobic digestion is quite

appropriate.


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WHO recognizes that access to adequate water suppliesis a fundamental human right.

Water-related diseases are a human tragedy , killingmillions of people each year (account for 80% of alldeaths in developing countries).


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Water-borne diseases . Water-based diseases.

Water-related vector diseases.

Water-scarce ( also called water-washed)disease


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Water borne diseases are dirty-waterdiseasesthose caused water that has been contaminated

by human ,animal ,or chemical wastes


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Water-based diseases are caused by aquatic

organisms that spend part of their life cycle in thewater and another part as parasite of animals.


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Water-related vector diseases that are transmitted by

vectors-insects or other animals .


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Water-related vector diseases: that are transmitted byvectors-insects or other animals .

Dengue fever ( bone crusher disease)

Cause : virusSymptoms fever,chills,headache,painin jointsTransmission: mosquito bite

Water-scarce Diseases ( Water Water-washed Diseases.

Water-scarce diseases: thrive in conditions where freshwateris scarce and sanitation poor


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1. Cholera:

Cause : Bacteria Cause

Symptoms :diarrhoea, vomiting, dehydration lead to death.

2.Amoebic dysentery:

Cause : ProtozoaCause

Symptoms :diarrhoea, dehydration.

3.Diarrhealdisease (including :amoebic and bacillary dysentery)

Cause : Bacteria ,Viruses ,and Protozoa Cause



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4.HepatitisCause : Viruses

Symptoms :body weakness, loss of appetite, abdominal discomfort.

5.Typhoid

Cause : Bacteria Cause


6.Ascariasis

Cause :parasitic roundwormsSymptoms : enlargement of liver, toxicity,pneumonia ,nutritional deficiency.Transmission:Faecalsoil-oral


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Fifth Lecture 1

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