Environmental Engineering I-61350 An-Najah National University College of Engineering Environmental Engineering I-61350 Chapter 6 Water Quality Assessment Dr. Sameer Shadeed Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Water Quality Assessment Chemical Commonly measured chemical parameters include pH, alkalinity, hardness, nitrates, nitrites and ammonia, ortho-and total phosphates, and dissolved oxygen and biochemical oxygen demand The presence of fecal coliform, a bacteria, is also determined using a chemical test In addition, some "chemical" measurements actually indicate the physical presence of pollutants in water These include measurements such as conductivity and density Dr. Sameer Shadeed

Chemical: pH Water dissociates slightly into hydrogen ions (protons, H+) and hydroxide ions (OH−) as the following reaction The equilibrium expression for this reaction is [H2O] is essentially a constant that can be included in the equilibrium constant Kw (the dissociation constant for water). The result is the following: Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Chemical: pH To express hydrogen ion concentrations, the pH scale is used, where or That is, a neutral solution has a pH of 7 (written pH 7) Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Chemical: pH pH is a logarithmic scale ranging from 0 to 14 The pH scale, showing example values of pH for several common solutions Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Chemical: pH Solution: Example (pH of Tomato Juice): Find the hydrogen ion concentration and the hydroxide ion concentration in tomato juice having a pH of 4.1. Solution: The hydrogen ion concentration is The hydroxide ion concentration is Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Chemical: pH The pH is measure using a pH meter Dr. Sameer Shadeed Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Chemical: pH If stream water has a pH less than 5.5, it may be too acidic for fish to survive in While stream water with a pH greater than 8.6 may be too basic A change in stream water pH can also affect aquatic life indirectly by altering other aspects of water chemistry For example, low pH levels can increase the solubility of certain heavy metals This allows the metals to be more easily absorbed by aquatic organisms Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Hard water can cause problems in a home Chemical: Hardness In most cases, hardness is a reflection of the amount of calcium and magnesium entering water through the weathering of rock such as limestone (CaCO3) Hard water can cause problems in a home Soft: 0-60 mg/L Moderately hard: 61-120 mg/L Hard: 121-180 mg/L Very hard: >181 mg/L Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Chemical: Alkalinity The quantity of base present in water defines what is known as total alkalinity. Carbonates and bicarbonates are the most common and most important components of alkalinity Total alkalinity is expressed as milligrams per liter or parts per million calciu m carbonate (mg/L or ppm CaCO3). A total alkalinity of 20 mg/L or more is necessary for good pond productivity. A desirable range of total alkalinity for fish culture is between 75 and 200 mg/L CaCO3. Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Chemical: Nitrates, Nitrites and Ammonia Nitrogen is an essential nutrient that is required by all plants and animals for the formation of amino acids In its molecular form, nitrogen cannot be used by most aquatic plants, therefore it must be converted to another form One such form is ammonia (NH3). Ammonia may be taken up by plants or oxidized by bacteria into nitrate (NO3-) or nitrite (NO2-) Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Chemical: Nitrates, Nitrites and Ammonia Excessive concentrations of nitrogen can lead to eutrophication and subsequent degradation of water quality Common sources of excessive nitrogen include sewage and agricultural runoff Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Chemical: Ortho- and Total Phosphate Phosphorus is a nutrient essential for the metabolic reactions of plants and animals Once it enters the groundwater or a stream, it quickly bonds to soil particles, making it temporarily unavailable to living organisms Since it naturally occurs in low levels, phosphorus is often the "growth-limiting" factor for plants Phosphorus occurs in several forms-both inorganic and organic Inorganic orthophosphate (PO43-) is the only form available to living organisms Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Chemical: Ortho- and Total Phosphate Since the phosphorus requirements of algae are minimal, rapid algal growth occurs when excess phosphorus is present in streams Common sources of excess phosphorus include agricultural runoff from feed lots and fertilized fields, and sewage that contains organic phosphorus as well as inorganic phosphorus in products such as detergents The resulting algal bloom can lead to eutrophication and the subsequent degradation of stream water quality Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Water Quality Assessment Physical The physical parameters of water quality can be broken down into many topics such as turbidity, color, temperature, taste and odor One of the best barometers of a water is its actual temperature in its natural ecosystem Temperature affects sediment and microbial growth among other source of water characteristics Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Physical: Temperature The water temperature of a water source is very important for water quality Many of the physical, biological, and chemical characteristics of a water source are directly affected by temperature For example, temperature influences: 1. The amount of oxygen that can be dissolved in water; 2. The rate of photosynthesis by algae and larger aquatic plants; 3. The metabolic rates of aquatic organisms; The sensitivity of organisms to toxic wastes, parasites, and diseases Remember, cool water can hold more oxygen than warm water, because gases are more easily dissolved in cool water Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Physical: Temperature As water temperature rises, the rate of photosynthesis and plant growth also increases. More plants grow and die. As plants die, they are decomposed by bacteria that consume oxygen Therefore, when the rate of photosynthesis is increased, the need for oxygen in the water (BOD) is also increased The metabolic rate of organisms also rises with increasing water temperatures, resulting in even greater oxygen demand The life cycles of aquatic insects tend to speed up in warm water Animals that feed on these insects can be negatively affected, particularly birds that depend on insects emerging at key periods during their migratory flights Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Physical: Turbidity Turbidity is a measure of the relative clarity of water: the greater the turbidity, the murkier the water Turbidity increases as a result of suspended solids in the water that reduce the transmission of light Suspended solids are varied, ranging from clay, silt, and plankton, to industrial wastes and sewage High turbidity may be caused by soil erosion, waste discharge, urban runoff, abundant bottom feeders (such as carp) that stir up bottom sediments, or algal growth The presence of suspended solids may cause color changes in water, from nearly white to red-brown, or to green from algal blooms Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Physical: Turbidity A turbidimeter is an optical device that measures the scattering of light, and provides a relative measure of turbidity in Nephelometer Turbidity Units (NTUs) The smaller the value obtained from this method, the less turbid the water In general, a turbidity value of > 40 NTU for at least twenty-four hours indicates a problem Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Physical: Conductivity and Density Conductivity is the ability of water to carry an electrical current It indicates the physical presence of dissolved chemicals in the water For example, when sodium chloride (NaCl, table salt) dissolves in water, it dissociates into Na+ and Cl- ions The movement of these ions conducts electricity through the water The dissociation of naturally-occurring, inorganic compounds is the main source of ions in water Conductivity can also increase as a result of heavy metal ions released from pollutants such as acid mine drainage Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Physical: Conductivity and Density Like conductivity, water density is an indicator of the physical presence of chemicals in water The density of water is related to salt content and water temperature This is a very useful parameter to measure because the salinity of a body of water is one of the main factors determining what organisms will be found there Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Water Quality Assessment Biological Biological attributes of a waterway can be important indicators of water quality Biological attributes refer to the number and types of organisms that inhabit a waterway The poorer the quality of water, the fewer the number and types of organisms that can live in it When assessing water quality, it is also important to look at the quality of organisms that live in a waterway Some species are more sensitive to chemical and physical changes in their habitat than other species If species that tend to be sensitive to pollution are present in a waterway, then that waterway most likely has good water quality Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Biological: Coliform Bacteria Coliform bacteria are organisms that are present in the environment and in the feces 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 feces of humans or animals Testing drinking water for all possible pathogens is complex, time-consuming, and expensive Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Biological: Coliform Bacteria It is relatively easy and inexpensive to test for coliform bacteria If coliform bacteria are found in a water sample, water system operators work to find the source of contamination and restore safe drinking water Generally, if environmental contamination can enter the system, there may also be a way for pathogens to enter the system Therefore, it is important to find the source and resolve the problem Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Biological: Coliform Bacteria Total, Fecal, and E. coli There are three different groups of coliform bacteria; each has a different level of risk Total coliform, fecal coliform, and E. coli are all indicators of drinking water quality Total coliform bacteria are a collection of relatively harmless microorganisms that live in large numbers in soils, plants and in intestines of warm-blooded (humans) and cold-blooded animals. Coliform aid in the digestion of food There are 16 species of total coliform found in soils, plants and in animal and human waste A subgroup of coliform, called fecal coliform bacteria, is different from the total coliform group because they can grow at higher temperatures and are found only in the fecal waste of warm-blooded animals Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Biological: Coliform Bacteria Total, Fecal, and E. coli There are 6 species of fecal coliform bacteria found in animal and human waste. E. coli is one type of the 6 species of fecal coliform bacteria A rare strain of E. coli that you may have seen in the news can cause potentially dangerous outbreaks and illness. This strain is called E. coli 0157 If only total coliform bacteria are detected in drinking water, the source is probably environmental If total coliform is present, the sample will also be tested for either fecal coliform or E. coli, depending on the lab testing method Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Biological: Fecal Coliform Fecal coliforms are types of total coliform that mostly exist in feces. Fecal contamination is not likely Fecal coliform is a bacteria that occurs in the digestive tracks of warm-blooded animals Fecal coliform can enter a stream by direct discharge from mammals and birds, from agricultural runoff, or from open or broken sewers Fecal coliform is itself non-pathogenic. However, it is evidence of the presence of fecal wastes that may contain pathogenic microbes High levels of fecal coliform (greater than 200 colonies per 100 mL of water) are a good indicator that pathogenic microorganisms may be present Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Biological: Fecal Coliform Disease-causing microorganisms can enter the body though cuts in one's skin, or through one's mouth, eyes, ears, or nose They can result in health problems ranging from common diarrhea and ear infections to deadly diseases such as hepatitis, cholera, or even typhoid fever Therefore, it is suggested that one does not have total body contact with water containing levels of fecal coliform greater than 200 colonies per 100 mL of water Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Biological: Fecal Coliform Water sample with T.C contamination Water sample with F.C contamination Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Biological Contamination Water samples with and without Biological contamination Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Biological: E. coli E. coli is a sub-group of the fecal coliform group and is the predominant bacteria in the gut of warm blooded animals Most E. coli bacteria are harmless and are found in great quantities in the intestines of people and warm-blooded animals. Some strains, however, can cause illness The presence of E. coli in a drinking water sample almost always indicates recent fecal contamination– meaning there is a greater risk that pathogens are present A water test will give you results for both E. coli and total coliform Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Which Diseases Can be Found in Water When E. Coli is Present? Disease-causing microorganisms are known as “pathogens” and include: Bacteria that cause cholera and typhoid-fever Protozoa that cause dysentery Viruses that cause polio and hepatitis Helminths such as roundworm and tapeworm Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Can Coliform Harm Your Health? Finding coliform or other bacteria in water does not necessarily always mean you will become ill However, if these organisms are present, other disease-causing organisms may also be present The presence of fecal contamination is a sign that a possible health risk exists for individuals exposed to this water Health symptoms related to drinking or swallowing water contaminated with fecal coliform bacteria generally range from no ill effects to cramps and diarrhea Sanitarians and those who test water look for total and fecal coliform bacteria to alert people to the possible dangers and suggest proper treatments to remove potentially harmful bacteria from the water The presence of any fecal coliform in drinking water is of immediate concern as many diseases can be spread through fecal transmission Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

What Happens if Coliform Bacteria are Found in my Water? When coliform bacteria are found, water systems investigate to find out how the contamination got into the water They collect additional, or "repeat," water samples for testing, and often inspect the entire system Taking repeat samples helps determine whether an actual problem exists in the system If any of the repeat samples detect coliform bacteria, the initial findings are considered confirmed Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Solids The usual definition of solids is the residue on evaporation at 103 oC. These solids are known as Total Solids (TS) The test is conducted by placing a known volume of sample in a large evaporating dish and allowing the water to evaporate The TS are then calculated as where TS = total solids, mg/L Wds = weight of dish plus the dry solids after avaporation, g Wd = weight of clean dish, g V = volume of sample, mL Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Solids TS can be divided into two fractions: dissolved solids (DS) and suspended solids (SS) In water, the salt is an example of DS while the sand would be measure as a SS A Gooch crucible is used to seperate SS from DS. The crucible has holes on the bottom on which a glass fiber filter is placed The sample is drawn through the crucible. The SS is retained on the filter while the DS passes through Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Solids The SS are then calculated as where SS = suspended solids, mg/L Wdf = weight of dish plus the dry filtered solids, g Wd = weight of clean crucible, g V = volume of sample, mL Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Solids TS can be classified in another way: those that are volatilized at high temperature (volatile solids, VS) and those that are note (fixed solids, FS) VS are mostly organic, at 600 oC, the temperature at which the combustion takes place The FS can be expressed as where FS = fixed solids, mg/L Wdu = weight of dish plus unberned solids, g Wd = weight of clean crucible, g V = volume of sample, mL Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Solids The VS can then be calculated as where VS = volatile solids, mg/L Example: Given the following data: The weight of a dish = 48.6212 g. A 100 mL sample is placed in the dish and the water is evaporated. The weight of the dish and dry solids = 48.6432 g. The dish is placed in a 600oC furnace for 24 hours and then cooled in a desiccator. The weight of the cooled dish and residue (unburned solids = 48.6300 g. Find the total, volatile, and fixed solids. Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed

Solids Solution Dr. Sameer Shadeed Environmental Engineering I −Summer 2010 Dr. Sameer Shadeed