WATER POLLUTION PROCEDURES

WATER POLLUTION PROCEDURES (SIMPLIFIED

WATER POLLUTION PARAMETERS AND PROCEDURE

BIOCHEMICAL OXYGEN DEMAND (BOD)

It is generally known that BOD, Biochemical Oxygen Demand or Biological Oxygen Demand is a measurement of the amount of dissolved oxygen (DO) that is used by aerobic microorganism when decomposing organic matter in water. It is commonly expressed in milligrams of oxygen consumed per liter of sample during 5 days (BOD5) of incubation at 20°C and it is often used as a surrogate of the degree of organic pollution of water.

Biochemical Oxygen Demand is an important water quality parameter because it provides an index to asses the effects  discharged wastewater will have on the receiving environment. The greater the BOD, the more oxygen needed by the organic matter. If the amount of DO consumed by bacteria is exceeded the supply DO from aquatic plants, algae photosynthesis or diffusing of air will gradually formed, making the environment is unsuitable for aquatic ecosystem. As a result, dramatic depletion can lead to hypoxia and anoxic environment.

Sources of BOD include topsoil, leaves and woody debris, animal manure, effluents from pulp and paper mills, wastewater treatment plants, feedlots and food processing plants, falling septic system and urban stormwater runoff.

PROCEDURE

1.Pour the polluted water sample into 100 ml of beaker .
2.Check and record the pH of the water sample and its temperature.
3.The pH of the water must be within the range of 6.5 to 7.5. If the pH of the water to be below than 6.5, it is necessary to dilute with alkali solution. This may be true to dilute with acidic solution if the pH is above to 7.5.
4.Prepare 5 samples which include of the DO sample, blank solution, 25 ml, 50 ml and 100 ml of diluted water samples each.
5.Pour the water samples and blank solution (deionized water) into the BOD bottle and check the DO reading for both samples using dissolved oxygen meter.
6.Record the DO reading for both the samples.
7.Measure about 25 ml of water sample using 100 ml of calibrated measuring cylinder and pour into the BOD bottle.
8.Pour the BOD bottle with deionized water until full. 
9.Check the DO reading after perform 25 ml of dilution water samples.
10.Put a one shot of nitrification inhibator into the BOD bottle.
11.Close the BOD bottle with a cap and make sure no formation of air bubbles is produced within the water sample and fill it with deionized water until it split out. 
12.Seal the entire cap of the BOD bottle with parafilm.
13.Repeat step 7 until 12 for the dilution of 50 ml and 100 ml of the water samples.
14.Stored all the 5 samples in the thermostat for 5 consecutive days.
15.After 5 days, record the DO reading for all the samples and compare the initial reading of DO for the water samples. 


TOTAL KJEHLDAHL NITROGEN (TKN)

Total Kjehldahl Nitrogen can be specifically known as the combination of organically bound nitrogen and ammonia in wastewater. The organically bound nitrogen must be released from the organic matter by a process of digestion prior the analysis. This form of nitrogen is usually much bigger on influent (untreated waste) samples then effluent samples. Total nitrogen is the combination of organic nitrogen and inorganic nitrogen  such as NH3 and NO3.

An abundance of nutrients in water leads to excess plant growth and eventually to eutrophication. This result in prolific algal growth that have a deleterious impacts on other aquatic life, drinking water supplies and recreation. Ammonia at high concentration is toxic to aquatic life. Organic nitrogen is not immediately available for biological activity. Therefore, it does not contribute to furthering plant proliferation until decomposition to the inorganic forms of nitrogen occurs.

PROCEDURE

1.Pour 100 ml of water sample into large test tube.
2.Prepare 2 samples of 100 ml of blank solution into the large test tube.
3.Pour 10 ml of sulphuric acid into each the test tube.
4.Insert 2 tablets of kjedall into each the test tube.
5.Assemble the equipment and set for 2 hours and 10 minutes in inte fume chamber.
6.After 2 hours and 10 minutes, use holder to transfer the test tube into the distillation unit for 3 minutes.
7.Drop an indicator (phenolpthalein) into each the test tube containing the water samples.
8.If the sample turns pink indicates that the nitrogen is absent.
9.Otherwise, if there is a changes in the sample to green means the sample has a presence of nitrogen. TKN is achieved.

TOTAL SUSPENDED SOLIDS (TSS)

Total Suspended Solids can be defined as solids in water that can be trapped by a filter. TSS can include a wide variety of material such as silt, decaying plant and animal matter, industrial wastes and sewage. High concentrations of suspended solids can cause many problems for stream health and aquatic life .

High concentration of suspended solids can lower water quality by absorbing light. Waters then become warmer and lessen the ability of the water to hold oxygen necessary for aquatic life. Because aquatic plant also receive less light, photosynthesis decreases and less oxygen is produced. The combination of warmer water, less light and less oxygen makes it impossible for aquatic living things form of life exist.

Suspended solids affect life in other 15 ways. They can clog fish gills, reduce growth rates, decrease resistance to disease and prevent egg and larval development. Particles that settle out can smother fish eggs and those of aquatic insects as well as suffocate newly-hatched larvae. The material that settles also fills the spaces between rocks and makes these microhabitats unsuitable for various aquatic insects such as caddisfly larva.

PROCEDURE

1.Place the microfiber filter paper into the porcelain.
2.Heat up the porcelain containing filter paper in an oven for 20 minutes.
3.Cool the porcelain in a dessicator for 15 minutes.
4.Weight the mass of filter paper after the cooling.
5.Assemble the filtration pump and place the cooled filter paper at its center.
6.Pour the water sample at the top and let the sample to flow through the paper into flask at the bottom.
7.Switch on the pump simultaneously.
8.Let the water dripped down to the bottom and until the last drop of the water flow.
9.Stop the pump afterwards.
10.Weight the filter paper and record its weight.
11.TSS can be directly obtained from the subtraction of final and initial weight of the filter paper.

TOTAL DISSOLVED SOLID (TDS)

A Total Dissolved Solid (TDS)  is a measure of the combined total of organic and inorganic substances contained in a liquid. This included anything present in water other than the pure water molecules. These solids are primarily minerals, salts and organic matter that can be general indicator of water quality. TDS is directly related to the purity of water and the quality of water purification systems and affects everything that consumes, lives in, or uses water, whether organic or inorganic, whether for better or for worse.

High TDS indicated hard water, which can cause scale build up in pipes and appliances. Scale build up reduces performance and adds system maintenance cost. Dissolved solid also come from inorganic materials such as rocks and air that may contain calcium bicarbonate, nitrogen, iron phosphorus, sulfur and other minerals. Many of these materials from salts which are compounds that contain both a metal and nonmetal. Salts usually dissolve in water forming ions. Ions are particles that have a positive or negative chrage.

PROCEDURE

1.Heat up the porcelain in an oven for 20 minutes.
2.Cool the porcelain in the dessicator for 15 minutes.
3.Weight the porcelain and record.
4.Place the filter sample from TSS into the porcelain.
5.Heat the porcelain and water in 180C in the oven until all water is evaporated.
6.Cool in the dessicator for 15 minutes.
7.Weight and record again the porcelain
8.TDS can be obtained by subtracting the final weight and initial weight of porcelain 

TURBIDITY

The definition of turbidity is the cloudiness or haziness of a fluid caused by suspended solids that are usually invisible to the naked eye. The measurement of turbidity is an important test when trying to determine the quality of water. It is an aggregate optical property of the water and does not identify individual substances. Organism like phytoplankton can contribute to turbidity in open water. Erosion and effluent from highly urbanized zones contribute to the turbidity of waters in those areas. Construction for instance can lead to raise levels of sediment which run off into waterways during storms.

High turbidity can cause the suspended particles absorb heat from the sunlight, making turbid waters become warmer, and so reducing the concentration of oxygen in the water. Some organisms also can’t survive in warmer water. The suspended particles scatter the light, thus decreasing the photosynthetic activity of plants and algae, which contributes to lowering the oxygen concentration even more. As a consequence of the particles settling to the bottom, shallow lakes fill in faster, fish eggs and insect larvae are covered and suffocated, gill structures get clogged or damaged.

PROCEDURE

1.Switch on the power supply of the turbidimeter.
2.Press the 1 N.T.U button and concide the scale with zero using focussing template.
3.Repeat step 2 of the experiment.
4.Place the water sample taken in HACH turbidimeter
5.Use a cell rise if the turbidity meter is more than 100 N.T.U and get the turbidity dilution factor.

CONDUCTIVITY

Conductivity in the context is the measurement of the ability of water to conduct an electric current. The greater the the content of ions in the water, the more current the water can carry. Ions are dissolved metals and other dissolved materials. Specific conductivity may be used to estimate the total ion concentration of the water and is often used as an alternative measure of dissolved solid. It is often possible to establish a correlation between conductivity and dissolved solids for a specific body of water. Distilled or deionized water can act as an insulator due to its very low conductivity value. Sea water on the other hand has a very high conductivity value.

Ions conduct electricity due to their positive and negative charges. When electrolytes dissolve in water, they split into positively charged (cation) and negatively charged (anion) particles. As the dissolved substances split in water, the concentrations of each positive and negative charge remain equal. This means that even though the conductivity of water increases with added ions, it remains electrically neutral.

PROCEDURE

1.Pour the water samples into the 100 ml of beaker.
2.Dip the sensor of the conductivity meter into the water sample.
3.Read the conductivity once the reading displayed becomes stable.
4.Record the conductivity of the water sample.

COLOUR

This is a measure of the dissolved colouring compounds in water. The colour of water is attributed to the presence of organic and inorganic materials, different materials absorb different light frequencies. Colour is expressed as Pt-Co units according to the platinum-cobalt scale. Water colour can naturally range from 0-300 Pt-Co. Higher values are associated with swamps and bog. Colour is regarded as a pollution problem in terms aesthetics but is not generally considered a detriment to aquatic life. Increased colour may interfere with the passage of light, thereby impending photosynthesis.

PROCEDURE

1.Place the cell containing the blank solution(deionized water) in the sample compartment of spectrophotometer with the transparent sides facing light sources.
2.Close the sample compartment lid.
3.Press the autozero key to set the zero absorbance.
4.Repeat step 2 to 3 with water sample.
5.Place the cell containing the water sample in the measuring position.
6.Close the sample compartment lid.
7.Press the start key to measure the colour.
8.Record the reading as colour units for the sample.