Bio componets proposalc14123361t

Project proposal presentation

ByMunashe C mazodze

c14123361t

Analysis of the biological components of the ground water at selected industrial and residential areas in Chinhoyi

introduction

groundwater Significance and Contamination

Water is essential for all forms of life and certain human activities.

In the course of survival, certain living organisms may contaminate water required for use by others.

Human activities may also lead to contamination of water

sources with toxic substances.

*Water Quality StandardsRegulations on the purity of water used for various

purposes.

Mandatory limits concerning constituents and contaminants of water known to be hazardous and/or cause inconveniencies.

Sets of procedures and practices required to meet the mandatory limits.

*WHO, The guideline for drinking water quality recommendations; World Health Organization; Geneva, (2002)

Why control water standards?

Health and survival of man and other organisms depends on the purity of the water they use.

Different measures are used to access and control water quality with varying degrees of relevance and acceptability.

Hence the need to adopt generalized methods of

assessment and arbitrary standards for water quality.

Water Quality Parameters

Physical properties

Chemical / Inorganic Substances

Organic Constituents

Disinfectants and their by-products

Radionuclides

Microbiological Parameters.

microbiological

Coliform bacteria coliform bacteria are organisms that are present in the environment and in the faeces of

all warm-blooded animals and humans*

Coliform bacteria will not likely cause illness. However, their presence in drinking water indicates that disease-causing organisms (pathogens) could be in the water system

Most pathogens that can contaminate water supplies come from the faeces of humans or animals

It is relatively easy and inexpensive to test for coliform bacteria. If coliform bacteria are found in a water sample, there is need to work to find the source of contamination and restore safe drinking water

*Wallace, R. (2000). Maxcy-Rosenau-Last Public Health and Preventive Medicine. Stamford, CT

Microbiological Analysis

Offers the most sensitive test for the detection of recent and potentially dangerous faecal pollution

Provides a hygienic assessment of water quality with high sensitivity and specificity

It is important to examine water sources frequently by simple tests rather than infrequently by more complicated test or

series of tests

Indicator OrganismsInvestigation for individual specific pathogens is rarely

practical since they are fewer in numbers than the non-pathogenic organisms and their detection methods are too demanding.*

Therefore, indicators of human/animal pollution e.g. coliforms are used to access water quality.*


IndicatorsE. coli

Faecal Coliforms

Total Coliforms

Faecal Streptococci

chemical parameters

CHEMICAL OXYGEN DEMAND

COD is the total amount of oxygen required to

chemically oxidize the bio degradable and non-

biodegradable organic matter.*

*Appleton & Lange. Bhandari N. S. and Kapil Nayal, E-Journal of Chemistry, 5(2), 342 (2008)

The organic matter present in water can be measured in number of ways.

Organic matter is often assessed in terms of oxygen required to completely oxidise the organic matter to CO2 , H20 and other oxidized species.

The oxygen required to oxidise the organic matter present in a given

waste water can be theoretically calculated .If the organic compounds

and their concentration are known the oxygen demand of the sample

can be accurately computed but it is impossible to

-know the details of organic compounds Present in raw water or

waste water. The COD is therefore determined by performing a

laboratory test On given water sample using a strong oxidant like

dichromate solution.

It is expressed in milligrams per litre (mg/L) also referred to as ppm (parts per million), which indicates the mass of oxygen consumed per litre of solution.

Biological Oxygen Demand

BOD is the amount of dissolved oxygen needed by aerobic biological organism in a body of water to breakdown organic material present in a given water sample at certain temperature over a specific time period*

*Manivaskam N., Physico-chemical examination, sewage and industrial, Pragati Prakashan, Meerut, (1986)

Biological oxygen demand The test measures molecular oxygen utilised during a specified

incubation period for the biochemical degradation of organic material and the oxygen used to oxidise inorganic material such as sulphides and ferrous iron.*

It may measure the amount of oxygen used to oxidise reduce forms of nitrogen.

Pure water have a BOD of 1mg/L* Hypoxia: When dissolve oxygen content below 3.0 mg/L. Many Species

move elsewhere and immobile species may die* anoxia: When dissolve oxygen content below 0.5 mg/L. All aerobic

species will die* *Trivedi P. K. and Goel P. K, Chemical and biological methods for water pollution studies, Env. Publication , Karad, (1986)

High BOD and Low BOD:

In a body of water with large amount of decaying organic material , the dissolved oxygen level may drop by 90 %, this would represent High BOD*

In a body of water with small amount of decaying organic material , the dissolved oxygen level may drop by 10 %, this would represent Low BOD*

*Manivaskam N., Physico-chemical examination, sewage and industrial, Pragati Prakashan, Meerut, (1986)

Phosphate present in Soap and detergent that enhances the growth of algal blooms. As a result depletion of oxygen occur.

Causes of High Bod

Fertilizer contains Nitrate contributes to high BOD Adapted from [APHA Standard methods for examination of water and waste water; American Public health Association, Washington, DC, (1998)]

1

2

1.:Eutrophication

Excess of nitrates/ artificial

fertilisers/ phosphates

Excessive growth of

plants/ algae

Dissolved O2 not sufficient to cope with anaerobic

decomposition

NH3, H2S, PH3 poison water

Aquatic species dies

MORE anaerobic

decay

Water bodies = Devoid of life

2.Thermal Water Pollution

Thermal pollution is the ‘degradation of water quality by any process that changes ambient water temperature’

Effects

1. • Increase Water Temperature

2. • Solubility of Water decreases

3.• Metabolic rate of aquatic organisms

increases

4. • Demand for O2 increases

Literature review

*Sampling, sample handling and preservations

Sampling order

Equipment decontamination

Sample handling and preservations

Sampling pointsMayur C. Shah, Prateek Shilpkar and Sangita Sharma, Asian J. Chem., 19(5), 3449 (2007)

Chemical oxygen demand (COD)

The DICHROMATE PRINCIPLE method of analysis for COD test

Water sample is refluxed in strong acidic solution with a known excess amount of potassium dichromate.*

After digestion, the remaining unreduced K2Cr2O7 is titrated with Ferrous Ammonium Sulfate (FAS)to determine K2Cr2O7 consumed.*

This gives us the oxidizable organic matter in terms of oxygen equivalent.*


CALCULATIONS

*The COD in mg/l is determined by the formula,

COD mg/l = (A-B)xNx8000 ml sample taken

A = ml of FAS required for blank. B = ml of FAS requires for sample.


ADVANTAGES OF COD TEST COD result are available much sooner than BOD test

results.

The COD test requires fewer manipulations of the sample.

The COD test oxidizes a wide range of chemical

compounds.

It can be standardize more easily.

Microbiological(total coliform)

Methods for Microbial Analysis

Microbial Analysis

Membrane filtration method

Multiple-tube method

Membrane Filtration Method

Aseptically introduce sample into sterile membrane filter assembly ( 0.2 or 0.45 μm)

Filter retains indicator organisms,transfer to a suitable culture medium and incubate

Count colonies and report results in CFU /100 ml

*Health risks of coliform bacteria The health effects of exposure to disease-causing bacteria, viruses, and parasites

in drinking water area varies.

The most common symptoms of waterborne illness include nausea, vomiting, and

diarrhoea. Infants, the elderly, and those with compromised immune systems may suffer more severe effects.

In extreme cases some pathogens may infect the lungs, skin, eyes, nervous system, kidneys, or liver and the effects may be more severe, chronic, or even fatal.


Biological Oxygen Demand

*Principle method for 5 day BOD test

the DO level (ppm) of ground water sample is recorded immediately.

And after recording initial DO, the groundwater sample is placed in an incubator in complete darkness at 20 C for 5 days and all light is excluded

If no incubator, wrap the water sample bottle in aluminum foil or black electrical tape and store in a dark place at room temperature (20o C ).

*Harilal C. C., Hashim A, Arun P. R. and Baji S., Journal of Ecology, Environment and Conservation, 10(2), 187 (2004)

DILUTION OF SAMPLE• Most relatively unpolluted streams have a BOD5 that

ranges from 1 to 8 mg/L • Dilution is necessary when the amount of DO

consumed by microorganisms is greater than the amount of DO available in the air-saturated.

• If the BOD5 value of a sample is less than 7 mg/L, sample dilution is not needed.

• The DO concentration after 5 days must be at least 1 mg/L and at least 2 mg/L lower in concentration than the initial DO

(American Public Health Association 1995).

BOD RANGE Millilitre of Sample Millilitre of Water

0-7 mg/L 300 0

6-21 mg/L 100 200

12-42 mg/L 50 250

30-105 mg/L 20 280

60-210 mg/L 10 290

[Adapted from Sawyer and McCarty, 1978. BOD5, 5-day biochemical oxygen demand]

Recommended sample volumes

*CALCULATION:The general equation for the determination of a BOD5 value is:BOD = D1-D2/PWhere D1 = initial DO of the sample,D2 = final DO of the sample after 5 days, andP = decimal volumetric fraction of sample used.

If 100 mL of sample are diluted to 300 mL, then P = 0.33. Notice that if no dilution was necessary, P = 1.0 and the BOD5 is determined by D1 - D2.*APHA Standard methods for the examination of water and waste water, Public Health Association, 19 th ed., Washington, DC, (1996)

Bio componets proposalc14123361t

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