Class D Water Operator Questions And Answers Rated A+.

Class D Water Operator Questions And Answers Rated A+. What are some physical characteristics of water? - correct answer. Temperature, turbidity, color, taste, odor What are some chemical characteristics of water? - correct answer. Hardness, pH, solids, and gases What is turbidity? - correct answer. the amount of suspended matter, such as clay, silt, organic matter, and microorganisms in water T/F Water is never found pure in nature. - correct answer. True Is turbidity more of a problem in groundwater or surface water? - correct answer. Surface water A system's filtered water must be _______ Nephelometric Turbidity Units (NTU) or less in at least 95% of the measurements taken each month, and no sample can exceed _____ NTU. - correct answer. 0.3 1 T/F True color is dissolved in water (in solution) and cannot be removed by filtering. - correct answer. True. Tea in water is an example of true color. Suspended color is called _______ color. - correct answer. apparent Color above ______ units is objectionable in a public water supply. - correct answer. 15 units A scale called the ________ measures odor. - correct answer. Threshold Odor Number (TON) Odor greater than a scale of _______ is undesirable. - correct answer. 3 Taste and odors in water result from _______, bacteria, decaying organic matter, gases, and chemicals such as manganese, zinc, copper, iron, magnesium, sodium, and potassium. - correct answer. algae Chemical characteristics of water generally cannot be detected by sight, smell, or taste and must be determined by __________. - correct answer. laboratory analysis Chemical laboratory analysis must be sampled _______ per year for surface water and normally _______ for groundwater. - correct answer. once/year for surface water once every three years for groundwater Water weighs ______ lbs/gal. - correct answer. 8.34 lbs/gal T/F For water, 1 mg/L is equal to 1 part per million (ppm) by weight. - correct answer. True Which two minerals mainly cause hardness in water? - correct answer. Calcium and magnesium Is hardness more of a problem in groundwater or surface water? - correct answer. Groundwater Water is considered hard when it exceeds _______. - correct answer. 100 mg/L of calcium carbonate The pH scale ranges from _____ to _____. - correct answer. 0 to 14 On the pH scale: 0 to <7 is ______. 7 is _______. >7 to 14 is ______. - correct answer. Acidic Neutral Basic or alkaline Sulfuric, hydrochloric, and nitric acids can be used to ______ pH. Caustic, lime, or soda ash can be used to ______ pH. - correct answer. Lower Raise Suspended solids can be removed by ________. - correct answer. Filtration Can dissolved solids be removed by filtration? - correct answer. No Total dissolved solids should not exceed________. - correct answer. 1000 mg/L What are three common gasses found in water? - correct answer. Hydrogen sulfide, carbon dioxide, and methane Excess ________ can cause blue baby syndrome. - correct answer. Nitrogen or Nitrates What is the major source of nitrogen into drinking water? - correct answer. Fertilizer and animal waste carried by rainwater runoff What is the EPA primary MCL (maximum contaminant level) for fluoride? - correct answer. 4.0 mg/L At what level will fluoride cause mottling of teeth, a condition known as fluorosis? - correct answer. 4.0 mg/L What is the state of Texas secondary standard for fluoride? - correct answer. 2.0 mg/L Trihalomethanes (THM) and Haloacetic Acids (HAA) are byproducts of drinking water ________. - correct answer. chlorination THM's and HAA's are byproducts formed when chlorine reacts with dissolved _________. - correct answer. natural organic matter, mostly plant life Combining chlorine with _______ greatly reduces THM and HAA formation. - correct answer. ammonia Is surface water or groundwater more likely to contain natural organic matter? - correct answer. surface water What is chloramine? - correct answer. Chlorine combined with ammonia What is free chlorine? - correct answer. Chlorine not combined with ammonia. Most groundwater systems do not have organic matter (which could cause THM and HAA byproducts) and therefore are allowed to use uncombined chlorine, called free chlorine. Why are most surface water treatment plants required to combine chlorine with ammonia (chloramine) before disinfecting the treated water? - correct answer. Surface water usually contains natural organics, and combining chlorine with ammonia greatly reduces THM and HAA formation. What is the MCL (maximum contaminant level) for THMs? - correct answer. 0.08 mg/L What is the MCL (maximum contaminant level) for HAAs? - correct answer. 0.06 mg/L The MCLG (maximum contaminant level goal) for lead is zero. What is the action level for lead? (in 10% or more of the samples) - correct answer. 0.015 mg/L