Water Technology - Jan 2012

Answers 1 d 2 b 3 True The free mineral acidity FMA of water is the amount of total mineral acidity TMA that is converted to the acid form by hydrogen ion exchange for the cations associated with anions other than alkalinity or silicates FMA is less than the TMA only by the amount of sodium ion not exchanged for hydrogen or sodium leakage 4 Higher lower Alkalinity anions take up and promote hydrogen ions exchanging off the cation resin The higher percentage of alkalinity thereby enhances higher cation exchange capacity and lower sodium leakage 5 Lower higher Mineral acidity anions such as chlorides sulfates fluorides and nitrates maintain hydrogen in its ionic state in water A buildup of hydrogen ions in water tends to drive the ion exchange equilibrium toward lower cation exchange capacity for the resin and toward higher leakage of sodium 6 b a Although conductivity instruments are used in obtaining approximate measures of the TDS of waters they are most accurate for monitoring changes in TDS A complete water analysis is the best means of obtaining accurate values of TDS 7 c Waters with high amounts of carbon dioxide carbon dioxide in water forms carbonic acid can have pH values less than 7 8 a Free carbon dioxide is considered to react as the monovalent bicarbonate anion CO2 will convert to carbonic acid H2CO3 in water and will exchange on the ion exchange resin as bicarbonate removal with ion exchange _______ a increases b decreases c is not affected 10 With high water temperature silica reactions _______ a affects the speed of reaction or exchange b affects the backwash bed expansion c both a and b d none of the above 9 Water temperature in ion exchange d H2CO3 c CO3 2 b H3CO3 exchange reactions a HCO3 act as the following ion in ion 8 Free carbon dioxide in water will usually to contain high amounts of dissolved _______ a silica b alkalinity c carbon dioxide d hardness 7 Water with a pH less than 7 is likely By The Water Quality Association WQA 26 Water Technology January 2012 measuring a or b a values of total dissolved solids TDS b changes in TDS for measuring a or b than for 6 Conductivity devices are more accurate in the water analysis the lower or higher the capacity and the lower or higher the leakage of sodium will be for cation resins operating in the hydrogen form acidity TMA of total anions 5 The higher the percentage total mineral and the lower or higher the leakage of sodium will be from cation resins operating in the hydrogen form the lower or higher the capacity 4 The higher the percentage of alkalinity acidity FMA to be different from total mineral acidity TMA in cation exchange portion of deionization a True b False 3 Sodium leakage causes free mineral is contributed by anions of _______ a alkalinity b chlorides and sulfates c silica d b and c 2 Total mineral acidity TMA of water divided by the total anions in water and multiplied by 100 will yield the waters _______ a alkalinity b pH c percentage of carbon d percentage of alkalinity carbonate and hydroxide 1 Calculating the total amount of bicarbonate CERTIFICATION ACTION LINE HCO3 9 c The effect on the exchange rate of ion exchange resins particularly at temperatures approaching waters freezing point is significant Adjustments in flow rates contact time should be made in such cold water conditions to maintain capacity and quality Also the lower the water temperature the higher becomes the viscosity of water and the greater will be the bed expansion with flow rate remaining the same Conversely with higher water temperature the water flow acts thinner and if the flow rate remains unchanged the backwash bed expansion may be less than that required to remove dirt and fine particles or to obtain good resin or bed classification 10 b Conversely to most ion exchange reactions which increase in reaction rate as the temperature goes up silica removal and leakage are adversely affected by high water temperature The higher temperature tends to solubilize more silica not removed during normal regeneration Questions about mineral acidity Answers to these questions appear at the bottom of this page Certification Action Line features questions and answers typical of those appearing in Water Quality Association WQA certification examinations Some answers may not satisfy everyone or every condition