Florida Wastewater Operator Class B Exam Study Guide - Current Edition Solutions

Florida Wastewater Operator Class B Exam Study Guide - Current Edition Solutions A common remedy for activated sludge system problems is to increase the waste activated sludge flow rate, when would an increase of WAS rate not be correct? - answer - When straggler Floc is present in clarifier and settleometer The chlorine residual is falling An inspection of the 150lb cylinder and chlorine feed equipment shows ice forming on the chlorine regulator and feed lines. The best method to fix the falling chlorine residual is? - answer - Put another chlorine cylinder online Caution must be used when adding caustic chemical to a digester. Lime can combine with carbon dioxide in the digester to form what problem? - answer - A dangerous vacuum How many gallons will the single piston, reciprocating sludge pump discharge per minute If the piston bore (diameter) is 6 inches and the stroke length is 11 inches? The pump runs at 99 revolutions per minute. - answer - 134gpm solve MCRT: Flow: 3.6mgd Basin volume: 5.0mg MLSS:2350mg/l WAS ss:4800mg/l WAS flow: 150000gpd Eff tss: 15mg/l - answer - 15 days There are high suspended solids in the water applied to the filters due to bulking sludge in the secondary clarifiers. Polymer is used as a filter aid chemical, but the effluent ability is worsening. What is the best method to correct the filter problem? - answer - Run jar tests to determine best Polymer dosage An advantage of a continuous backwash, up flow, deep bed sand filters is? - answer - Filters do not need to be taken out of service for backwashing The aeration tank dissolved oxygen has been running normal, 1.5 to 2.0 mg/L the whole month. Today's D.O. reading has spiked to nearly 6.0 mg/L in the aeration tank and the clarifier and plant effluent or cloudy. What is the most likely cause of the rise in D.O.? - answer - A toxic shock load of cyanide has entered the plant Plant fecal coliform counts do not meet state standards. The chlorine supply is not the problem and there is adequate vacuum and chlorine feed the chlorine contacting has no solids build up and the effluent flow is below design. What is the most likely cause of the poor fecal coliform kill? - answer - High chlorine demand from excessive nitrite in effluent The point, location or structure where wastewater discharges from a sewer, drain or other conduit is called what? - answer - Outfall The volatile acid to alkalinity ratio of a properly operating anaerobic digester is - answer - 0.1 parts acid to one part alkalinity (0.1 : 1.0) What is a disadvantage of running a digester in the thermophilic temperature range? - answer - The higher costs of heating the digester with natural gas What condition of a surface water, river or stream will allow more DO saturation? - answer - Cold water temperature Solids are washing out of the secondary clarifier of the activated sludge plant. Plant personnel increase the RAS flow rate, which slows the problem temporarily but then it worsens after 30 minutes. What is the cause of the plant problem? - answer - Increase of RAS flow decreased the detention time in the clarifier When operating upflow, continuous backwash sand filter that is discharging poor filtrate. What should you check? - answer - reject/washwater valves When using lime to precipitate phosphorus from treated effluent, it is important to maintain the pH at or above - answer - 11.0 Upward force of groundwater on sedimentation tank? groundwater depth: 6ft above tank bottom Tank width: 80ft wide Tank length: 157ft long - answer - 4,700,000lbs Luxury uptake phosphorus removal method is failing to remove permitted levels: Influent phosphorus is 8 mg/L. Fermentation basin phosphorus level is 10 mg/L. Aeration basin phosphorus is 8 mg/L. Effluent exceeds 1.0mg/l - answer - Poor release of phosphorus in fermentation basin Calculate the SVI for the activated sludge treatment plant: 30min sett:675 60min sett:420 MLSSmg/l:3650 MLVSSmg/l:74% - answer - 185ml/g According to ch