Water Treatment Operator Level 1 Sample Questions (Water Operator Certification Study Guide) with Complete Solutions

What are the two important factors impacting the effectiveness of chlorination? - ANSWER-Concentration of chlorine and contact time The treatment process that controls corrosion or scaling is known as what? - ANSWER-Stabilization Permanganate reactions are highly dependent on what factor? - ANSWER-pH It is hardest to kill the organism that causes what illness? - ANSWER-Cryptosporidiosis Disinfection of water wells with free chlorine requires exposure for how long and at what concentration? - ANSWER-12 to 24 hours; 50mg/L Flocculation basins are usually designed to provide for detention times of how long? - ANSWER-15 to 45 minutes Alum works best in a pH range of what? - ANSWER-5.8 to 7.5 What has little effect on colloidal particles because of their small size? - ANSWER-Gravity What natural electrical force keeps colloidal particles apart in water treatment? - ANSWER-Zeta potential What does the zeta potential measure? - ANSWER-The number of excess electrons found on the surface of all particulate matter What device collects the settled water as it leaves the sedimentation basin? - ANSWER-The effluent launder In solid-contact basins with fairly constant water quality parameters, how often should the solids concentration be determined? - ANSWER-At least twice per day What is the definition of decant? - ANSWER-To draw off the liquid from a vessel of any size without stirring up bottom sedimentation How often should sedimentation basins with mechanical sludge removal equipment be drained and inspected? - ANSWER-Once a year What is the most important reason to reduce turbidity? - ANSWER-To remove pathogens What is the filtration flow rate through a manganese greensand pressure filter at 10 degrees C? - ANSWER-2 to 3 gpm/sq ft