What is pollution….?

• “Pollution is an undesirable change in the physical, chemical or biological characteristics of our air, land and water that may or will harmfully affect human life or that of desirable species, or industrial processes, living conditions, and cultural assets; or may or will waste or deteriorate our raw material resources”

………”Waste management and control”

Committee on Pollution, National Academy of Sciences, 1966

Pollution…

Increasing population and needs of present

civilization

…therefore generation of waste

• Air, Water & Solid

…therefore immediate need for systems approach

to manage the environment

Waste Generation…

Processes & Activities

Domestic or Industrial Wastewater

Sludge Solidwaste Air Pollutants

Biodegradable or Non-biodegradable

Hazardous orNon-hazardous

Ranking of waste management actions … Waste Management Hierarchy

The 3R conceptReduceReuseRecycle

Types of pollutants

Air Pollution Noise Pollution Water Pollution Thermal Pollution Marine Pollution Soil Pollution Nuclear Pollution

• Sources

– Point – single large sources

– Non-point - a diffuse source of pollution that cannot be attributed

to a clearly identifiable, specific physical location or a defined

discharge channel.

• general runoff of sediments

• pesticide spraying

• fertilisers from farms an urban areas

• Water pollution -:may be defined as the presence in water of such quantity and of such nature as to impair the use of water for stated purpose. Pollution and contamination

• Pollution is the general term which includes contamination. Contamination makes water total unfit for the best use e.g. drinking. Colored water, saline water, smelling water, water containing floating bodies are the e.g of water pollution. Water containing harmful pathogenic bacteria is an example of water contamination.

• Physical • Chemical• Biological

• Physical -: color, odor, taste, temperature, turbidity• Turbidity -: suspended matter such as clay, slit etc.• It is measure of the extent to which light is either absorbed or scattered by

suspended material in water.• 5-10 units of turbidity• Turbidity is measured by turbidimeters• Jackson turbidimeter 25-100 JTU• Baylis turbimeter or nephelomter 0-2 ppm• Color• Dissolved OM from decaying vegetation, colored soil etc.• Iron oxides cause reddish water and managnese oxides cause brown or

black• Colored water not aesthetically acceptable to the public. Highly colored

water is unsuitable for dyeing, papermaking, dairy and food industry.• Excessive growth of algae• Permisiible limit is 20 ppm • Tintometer and color matching • Taste and odor• Presence of dissolved gases such as H2S, CH4, CO2, O2; mineral

substances like iron compounds, sulphates, Nacl etc.• It is measured by threshold odor number represents the dilution ratio at

which the odour is hardly detectable.• It should be 1 and never exceed 3 for public supplies.

• Chemical Characteristics• Total solids and suspended solids• TS -: Evaporate the water sample and weigh the dry residue left• S/S -: Filter the water sample and weigh the residue left on the filter paper.• Aesthetically displeasing and provides adsorption sites for chemical and

biological agents• Total dissolved solids: The material remaining after filtration for the

suspended solids. Evaporate the sample and weigh the remaining residue.• pH-: log of the reciprocal of hydrogen ions• Indicator of acidity or alkalinity of water• pH >7 alkaline caused by bicarbonates of calcium and magnesium• Alkalinity is defined as the quantity of ions in water that will react to

neutralize hydrogen ions.• Difficulty in chlorination, sediment deposit• pH < 7 acidic caused by the presence of mineral acids, free carbon

dioxide, sulphates of iron or aluminium.• corrosion

• Nitrogen -: the presence of nitrogen indicates the presence of organic matter (OM)

• Free ammonia• Organic nitrogen• Nitrites• Nitrates• Free ammonia represents the first stage of decomposition of

OM. The value should not exceed 0.15 mg/L• Organic nitrogen should not exceed 0.3 mg/L.• Nitrites indicate partly oxidised OM. It should be nil in

potable water.• Nitrates represent fully oxidized OM. • It is limited to 45 mg/L. • Above it will cause blue baby disease.

• Synthetic Organic Compound• Non Biodegradable

• Persist for long time• Pesticides and detergents• Pesticides • Surface runoff from agriculture lands, waste discharge by

pesticides manufacturers• DDT

• Biomagnification -: accumulation of pollutant as it go higher in trophic level

• Fresh water (0.00001 ppm) Plankton (0.05 ppm) fish ( 2 ppm) predatory birds (10 ppm)

• Detergents• basic ingredient is the surfactant (10-30%). It lowers the

surface tension and allows the dirt particles to become linked to water.

• The remainder is polyphosphate salts and whiteners • Surfactant concentration as low as 1 ppm cause foaming in

rivers and in sewage treatment plant• Surfactant used earlier was ABS ( alkyl benzene

sulphonate). Resistant to biodegradation• LAS (linear alkyl sulphonate) which is biodegradable.• Detergent builders releases phosphates in water bodies

leading to eutrophic conditions.

• Hardness -: It is the characteristics which prevents the formation of sufficient lather or foam, when such hard water are mixed with soap.

• Lead to greater soap consumption, scaling of boilers, causing incrustation of pipes.

• carbonate hardness-: bicarbonates and carbonates of calcium and magnesium

• Removed by simple boiling and adding lime

• non carbonate hardness-: sulphate, chloride and nitrates of calcium and magnesium.

• 75 ppm- soft; 200 ppm and above hard• For domestic supplies 75-115 ppm

• Flouride : • Concentration of approximately 1.0 mg/L helps to provide

dental cavities in children• But if its concentration exceed 1.5 mg/L leads to

discoloration of teeth. Excessive intake leads to bone fluorosis and other skeletal abnormalities.

• Metals

• Source: domestic, industrial or agriculture wastewater• Iron concentration of 0.3 mg/L and manganese

concentration of 0.05 mg/L can cause color problems.• Toxic metals : arsenic, cd, chromium, lead

• Organics: • Source : wastewater discharge or agriculture source• Biodegradable and non biodegradable• Biodegradable material consists of organics that can be

utilized for food by naturally occuring MO’s• Oxygen demanding nature of biodegradable organics is of

utmost importance in natural water systems

• The amount of oxygen consumed during microbial utilization of organics is called Biochemical oxygen demand (BOD).

• Nonbiodegradable Organics: phenols, cellulose, detergents, pesticides etc.

• Chemical oxygen demand: it measures both matter

• Biochemical Oxygen Demand or Biological Oxygen Demand (BOD) is a procedure for determining how fast biological organisms use up oxygen in a body of water. It is used in water quality management and assessment, ecology and environmental science.

Typical BOD of Various Sample Types

• Unpolluted Rivers <5 mg/L

• Moderately Polluted Rivers 5-10 mg/L

• Untreated Domestic Wastewater 150-300 mg/L

• Treated Domestic Wastewater 2-30 mg/L

• Untreated Dairy Waste 20,000-100,000

• BOD measures the rate of oxygen uptake by micro-organisms in a sample of water at a temperature of 20°C and over an elapsed period of five days in the dark.

• To ensure that all other conditions are equal, a very small amount of micro-organism seed is added to each sample being tested.. The BOD test is carried out by diluting the sample with de-ionized water with added nutrients, saturated with oxygen, inoculating it with a fixed aliquot of seed, measuring the dissolved oxygen and sealing the sample (to prevent further oxygen dissolving in). The sample is kept at 20 °C in the dark to prevent photosynthesis (and thereby the addition of

• oxygen) for five days, and the dissolved oxygen is measured again. The difference between the final DO and initial DO is the BOD

• The loss of dissolved oxygen in the sample, once corrections have been made for the degree of dilution, is called the BOD5. For carbonaceous BOD (cBOD), a nitrification inhibitor is added after the dilution water has been added to the sample. The inhibitor hinders the oxidation of nitrogen. This inhibition allows for measurement of carbonaceous oxygen demand (cBOD).

• BOD can be calculated by:

• Undiluted: Initial DO - Final DO = BOD

• Diluted: ((Initial DO - Final DO) x Dilution Factor

• Chloride content-: • Normally present due to Nacl• Concentration above 250 mg/L produce a salty taste in drinking water.• Biological characteristics• Pathogenic or non pathogenic bacteria• Non Pathogenic-: these are harmless and• Under certain conditions beneficial to human beings, animals and crops• Pathogenic bacteria -: harmful bacteria or organisms which can cause

serious water borne diseases.• Aerobic bacteria-: those require oxygen for their survival• Anaerobic bacteria-: those which flourish and thrive in the absence of free

oxygen• Facultative bacteria-: those which can survive with or without free

oxygen

Water borne diseases/pathogens

• Bacteria– Vibrio cholera - cholera– Yersinia enterocolitica - gastroenteritis– Escherichia coli - gastroenteritis– Shigella sp.- gastroenteritis– Listeria monocytogenes - flu-like symptoms– Salmonella sp. - gastroenteritis, typhoid

• Viruses– Polio Virus - paralytic poliomyelitis– Rotaviruses - gastroenteritis– Norwalk Viruses - gastroenteritis– Hepatitis Type A and E - liver inflammation

• Protozoa– Entamoeba histolytica - amoebic dysentery– Giardia lamblia - intestinal disease– Cryptosporidium - intestinal disease

Difficulties With Routine Testing Of Pathogens in Water• present in low numbers

• limited survival time

• numerous pathogens to analyze

• time and cost prohibitive

• need an indicator of potential pathogen contamination of water which is easy, reliable, inexpensive, quick, etc.

• Requirements of Indicator Organisms• present when pathogens present in water

• absent in uncontaminated water

• present in higher numbers than pathogens in contaminated water

• better survival in water than pathogens

• easy to analyze

• The usual routine test are conducted to detect and count the presence of coliform which in themselves are harmless

• E coli resides in the intestine of human being. It leaves the human body along with pathogens through body waste. These Ecoli live longer in water than the pathogenic bacteria, it is generally presumed that water will be safe and free from pathogenic bacteria, if no coliforms are present in it.