2.2 Water quality parameter – ppt download

Presentation on theme: “2.2 Water quality parameter”— Presentation transcript:

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2.2 Water quality parameter
Can be divided into three types: Physical Chemical Biological Environmental Engineering

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Physical Parameters a. Turbidity – measured in NTU/FTU Source(s): – Inorganic compounds such as clay, sand – Organic compounds such as plant fibre, human waste Effect(s): – Aesthetic – Adsorption point/centre for chemicals and micro-organisms – Health aspect

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b. Odour and Taste Source(s): – Inorganic compounds such as minerals, metals, salts (all of them give taste to water but no odour) – Organic compounds from petroleum and/or degradation of organic matters. (odour and taste) Effect(s): – Aesthetic – Health problems [reaction from sources and other chemicals such as chlorine (Cl2)]

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c. Temperature – measured in oC or oF Source(s): – Effect from ambience – Industrial activities – cooling system Effect(s): – Disturb biological activities such as micro-organism and aquatic life – Chemical properties such as the degree of gas solubility, density and viscosity

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d. Suspended solid – measured in mg/L Source(s): – Inorganic compounds such as clay, sand – Organic compounds such as plant fibre, human waste Effect(s): – Aesthetic – Adsorption point/centre for chemicals and micro-organisms – Health aspect

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Measurement of Total Solids (TS)
Evaporate a known volume of sample to dryness and weigh the residue. The total solid is expressed as milligrams per litre (mg/L).

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Measurement of Suspended Solids (SS)
Weigh a filter paper on an analytical balance. Place the filter paper on the filter apparatus. Apply vacuum and filter 100 mL (or a larger volume if total suspended matter is low) well mixed sample.

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Dry the filter paper in an oven at 103oC to 105oC for at least 1 hour.
After 1 hour, cool the filter paper in a desiccator and weigh. Repeat the drying cycle until a constant weight is attained or until weight loss is less than 0.5 mg.

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Suspended Solid (mg/L) = [(A-B) x 1000] / volume of sample Where:
A = weight of filter paper + suspended matter B = weight of filter paper Total Solid (mg/L) = Suspended Solid (mg/L) + Total Dissolved Solid (mg/L)

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Example: A solid analysis is to be conducted on a sample taken from Sungai UTM as follows: A Gosh crucible and a filter pad are dried to a constant mass of g. Two hundred millilitres of a well-shaken sample of the wastewater is passed through the filter. The crucible, filter, pad and removed solids are dried to a constant mass of g. One hundred millilitres of the filtrate [water passing through the filter in (ii) above] is placed in an evaporation dish that had been pre-weighed at g. The sample in (iv) is evaporated to dryness and the dish and residue are weighed at g.

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Both the crucible from (iii) and the evaporation dish from (v) are placed in a muffle furnace at 550oC for an hour. After cooling, the mass of the crucible is g and the mass of the dish is g. Obtain the suspended solids (mg/L), dissolved solids (TDS) (mg/L) and total solids (mg/L) in the sample.

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SOLUTION

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Chemical Parameters a. Total dissolved solid (TDS) – Solid left in water after the water is filtered and dried. Source(s): – Inorganic compounds – minerals, metals & gases – Organic compounds – product from degradation of organic matters, organic gas Effect(s): – Cause taste, colour and odour problems – Health aspect

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b. Organic compounds Definition : All organic compounds contain carbon in combination with one or more elements. Source(s): – Nature: fibres, vegetable oils, animal oils and fats, cellulose, starch, sugar. – Synthesis: a wide variety of compounds and materials prepared by manufacturing processes. E.g. DDT, polyvinylchloride. – Fermentation: Alcohols, acetone, glycerol, antibiotics, acids.

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Effect(s): Depletion of the dissolved oxygen in the water Destroying aquatic life Damaging the ecosystem Some organics can caused cancer Trihalomethane (THM-carcinogenic compound) are produced in water and wastewater treatment plants when natural organic compounds combine with chlorine added for disinfection purposes.

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c. Inorganic compounds Definition When placed in water, inorganic compounds dissociate into electrically charged atoms referred to as ions. All atoms linked in ionic bond. Can be classified into two: metal and non-metal

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i. Metal – Non toxic and toxic Non-toxic – Ca2+, Mn2+, Na+, Fe2+, Mg2+, Al3+, Cu2+, Zn2+ – dangerous for health if the concentration is high Source(s): Mineral, readily available from nature Effect(s): – Colour, odour, taste and turbidity – Deteriorate health (at high concentration)

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Toxic – As2+, Ba2+, Cd2+, Cr2+, Pb2+, Hg2+ Source(s): – Human activities such as mining and industries Effect(s): – Dangerous diseases such as cancer, abortion and deformation in new born baby

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ii. Non-metal – e.g. Si4+, Cl-, NO3- Source(s): Mineral Effect(s):
Effect(s): – Diseases heavy metal, NO2-  “blue baby syndrome” – Aesthetic Si+4  turbidity – Fluoride (F-) – Not good for health if it is taken in high concentration – Concentration of 1 mg/L is good for the growth of children teeth – Excessive concentration – colour on teeth and problem in bone growth

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d. Alkalinity Definition : The quantity of ions in water to neutralise acid or a measure of water strength to neutralise acid. Main constituents : bicarbonate (HCO3-), carbonate (CO32-), and hydroxide (OH-) ions. Source(s): – Mineral dissolved in water and air. – Human activities such as detergent (in wastewater), fertilisers, pesticide etc. Effect(s): – Non pleasant taste – Reaction between alkaline constituent and cation (positive ion) produces precipitation in pipe.

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e. Hardness Definition : A measure of “multivalent” cations in water such as Ca2+, Mg2+, Fe2+, Mn3+. Ca2+ and Mg2+ are very important Source(s): – Natural mineral on earth Effect(s): – Excessive soap usage – Precipitate form on hardware – Precipitate in pipe – temperature and pH increased

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Two kinds of hardness: Carbonate hardness Non-carbonate hardness