Card Set Information
which settles better, primary or biological sludge?
T or F- an underloaded aeration tank can typically produce shink, dark brown foam?
the amount of active biological mass in the aeration tank may be estimated by?
you have small,dense,pinpoint floc particles suspended in the secondary clarifier. probable cause is?
f/m ratio to low or over aeration
in settlements tests, you have slow settling (more than 2 hours) whats this indicate? young or old sludge? low or high blanket?
young sludge accompanied by a high blanket.
upon microscopic observation you fid filamentousmicroorgansims in your young sludge, name 3 causes.
1.low D.O/2. insufficient nutrients/ 3. warm waste water temp.
aerobic digester ph dropping below normal range. cause?
nitrification is occuring
a plant has thick scummy dark foam. cause?
sludge age is to high
fine dispersed floc floating throuout the clarifier and over weir . settleability test should show?
a good settling, dense compaction pinpoints floc in clear supernatant.
very stable dark tan foam on the aeration tanks of an activated sludge system, which sprays cannot break up. probable cause?
sludge age to high
staffing of wastewater plants are based on what?
flow and type of plant
one ton chlorine cylinders have how many operating valves. what are they for
2. one for gas one for liquid
a very stable, dark tan foam on the surface of an aeration tank indicates?
the sludge retention time is too long
if the settled activated sludge floats to the surface of the secondary clarifier in large clumps which of the following is the probable cause?
increase in denitrification rate
how would you correct the situation of cloudy effluent if the probable cause were shear?
reduce aeration rate, maintain blanket at 1-3 feet in clarifier, and monitor mlss
what effect will the addition of chlorine acid, carbon dioxide or sulfuric acid have on the ph of waste water?
chlorine in a liquid or gas form is called what? when combined with water it forms what?
free chlorine/ hypochlorus and hydroclhoric acids.
what is the necessary check to confirm the cause of blackish sudsy foam?
check diffusers for proper mixing and check RAS rate
how tight should the packing on a centrifugal pump be? and why?
it should be tightened so that an occasional drop of water will leak out, one drop per second. water keeps the pump cool. note: never put new packing on top of old packing.
chlorination of returned activated sludge is used when?
filamentuos organisme are present causing bulking