Chapter 4 –Water Quality (Hwk#4- pp.112-113 2,4,6,10,14) Chemistry Review

1. LECTURE #5 • Chapter 4 –Water Quality • (Hwk#4- pp.112-113 2,4,6,10,14) • Chemistry Review • Compound – A combination of Elements • Molecule – Smallest part of a Chemical compound • organic vs. inorganic- complex molecules of carbon in combinations with other elements is organic(i.e. organic pertains to living organisms and • an exception would be CO2) • covalent vs. ionic bonding – shared electron atomic structure (covalent) vs. positive and negative charge attraction (ionic)[H20 .vs. NaCl]

2. Chapter 4 –Water Quality • (Hwk#4- pp.121-122 2,4,6,10,14) • Chemistry Review • Solutions – a uniform mixture of two substances (solid, liquid, or gas) • Solvent – the largest substance found in the solution • Solutes – the smaller amount of the substances in a solution • Solubility Properties – Liquids (the warmer the more soluble), Gas (the warmer the less soluble,the lower the pressure, the lower the solubility) • [i.e. sugar in water, oxygen in water (table 4.3), exception is alcohol in water]

3. Chemistry Review • ionization– The dissociation or breaking apart of molecules (to charged particles) when dissolved into solution.[ ] • radicals – The dissociation of molecules into groups of atoms. [ ] OH is the hydroxyl radical. • Suspension vs. Colloids – Colloids are particles less than coarse suspension but gt. than the true solution [<0.1цm] and don’t settle in the solution. • [i.e. clay in water and fog in air are both colloids] • Tyndall effect – the scattering of light in a solution by colloids

4. Chemistry Review • Flocculation– The clumping together of colloidal particles by neutralizing the colloidal charges. • dilute .vs. saturation – qualitative descriptions for the concentration of solutes in a solution. • Concentration Units – mg/L=1ppm,μg/L=1ppb, • 1gpg=17.1 mg/L (for air - μg/m3) [1L of water weighs 1kg therefore 1L is equivalent to 106mg], • i.e. 3.5%=35000mg/L, 1mg/L=8.34#/million gallons

5. Chemistry Review • Acid – A substance that causes an increase in hydrogen ions, H+ • Base- A substance that causes an increase in hydroxyl radicals, OH- • pH – a dimensionless scale that measures alkalinity or acidic substance from 0 to 14.(the negative logarithm of the hydrogen ion concentration) • [i.e. water numerical value of the hydrogen ion concentration is ten to the minus seven. A ph of • 5 is ten times more acidic than a ph of 6, because it is logarithmic to the base 10-pp.90]

6. Chemistry Review • Organic Substances– molecular structure {Carbon • plus some other elements} • Organic compounds .vs. Organic chemicals • Hydrocarbons – contains only carbon and hydrogen • (i.e. Methane CH4[found in the decay process of sewage and sludge], Benzene C6H6 [simplest ring • hydrocarbon]) pp.90-91 • Organic chemicals (i.e. Alcohols) - Methanol CH3OH,hydrogen is replaced by hydroxyl radicals. i.e. solvents &fuel additives/Ethanol is a result of the fermentation of sugar and is used for alcoholic beverages.

7. Chemistry Review • Biodegradable – term for substances that can be broken down by microbes into simpler molecules • Carbohydrates –(contains C,O, and H) the basic product of photosynthesis and are biodegadable organic compounds.[i.e. glucose,sucrose (table sugar),etc.] • Starch and cellulose are more complex carbohydrates • fats are not very soluble in water • Proteins – –(contains C,O, H,N and S) are formed from amino acids are much more complex than carbohydrates

8. Water Quality • Turbidity– suspended particles which scatter light and create a murky or cloudiness in the water • Turbidity Unit (TU)–It is correlated to the interference of light passage in 1 mg/L of suspended silica. The nephelometers measure TUs. (TU<5 is not noticeable)pp. 92 • Temperature– fish optimum temperatures ranges between 15-32 degrees (i.e trout-15°, perch-24°,carp –32°) note: increase in water temperature decrease oxygen solubility. • Color, taste, odor – important for drinkability. • i.e.hydrogen sulfide gas is produced from decaying • organic matter. • Threshold #- the amount of water required to dilute the sample to remove the smell over the original volume.

9. Chemical Parameters • Dissolved Oxygen (DO)- is important for aquatic life as well as land animals. ( 9ppm @20ºc in water) • Biochemical Oxygen Demand (BOD)- The need for oxygen when microbes consume the DO while breaking down organic substances • Note: the higher the organic material the higher the BOD.(expressed as mg/L of oxygen) • BODL-ultimate BOD or the maximum amount of oxygen needed to biodegrade a given volume of waste.(BOD>10mg/L has sewage pollution)

10. Chemical Parameters • Nitrification- when microorganism begin feeding on noncarbonaceous ammonia after 8 to 10 days • Chemical Oxygen Demand(COD)-it measures • all organics, including nonbiodegradable substances. • This test can not be correlated to the BOD test. • Total Dissolved Solids(TDS)- The solids that remain as a residue after evaporating the sample from a dish • Total Suspended Solids(TSS)- The solids that are retained on the filter

11. Chemical Parameters • volatile solids- burns off at 550ºc • Hardness-term to express the properties of highly mineralized water (i.e. the concentration of Calcium and Magnesium in water from soils and rocks) • all organics, including nonbiodegradable substances. • This test can not be correlated to the BOD test. • Gas Chromotography/Mass Spectrometry-tests for organics substances • Atomic Absorption Spectrophotometers- detect heavy metals

14. Chemical Parameters • coliforms- bacteria that is always present in the human intestinal tract (E.coli) • [no coliform –no sewage – no pathogens] • Two methods for tesing: • Membrane Filter Method • Mulitple –Tube Fermentation Method