Here are the answers to O&M Quiz No. 4.
1. T or F - A cycle counter does not really need to be read because the numbers can be very large and hard to calculate.
Answer: False. Hopefully this was an easy one. A cycle counter is most commonly installed to keep track of how many times during the maintenance interval a pump starts and delivers effluent to another part of the system. The pump should be calibrated so the provider knows how much effluent is delivered each time the pump runs. These days they are often used in conjunction with a timer as a check on proper pump performance. In what I like to call “the old days,” or for on-demand systems, this is the method for keeping track of the hydraulic loading and whether the pump is running when it should. Over time the provider will have a sense of what the numbers should be during the maintenance interval and the seasonal variation. When numbers deviate from the expected, take time to identify the cause before there are larger problems with the system.
2. T or F - Your eyes straying from the task at hand is the most common cause for impact or splashback accidents.
Answer: True. It is common sense that the maintenance provider needs to pay attention to what he is doing. If you are distracted or not paying attention, accidents will happen. It is important to always protect yourself, as well as give warnings to anyone else in the vicinity, like a homeowner who might stand directly over your pressure hose because they don’t know any better.
3. T or F - The top of the scum layer can be over the baffles in an acceptable operating condition.
Answer: False. Again, hopefully this answer is common sense. One of the purposes of baffles in a septic tank is to keep the scum layer in the tank and not allow scum to move to the next treatment component. If it is above the baffles, the provider should look for some type of blockage in the piping at the outlet of the tank or some type of pipe constriction that is backing up the liquid in the tank. It could also mean there is a backup from the drainfield.
4. T or F - A trash tank and a holding tank operate the same way, applying the same principles.
Answer: False. A trash tank in front of an ATU is meant to operate like a septic tank: holding the larger solids and scum along with any other materials that would impact the unit. A holding tank holds everything, liquid and solids, until it is pumped clean and the process starts all over.
5. T or F - A septic tank uses gravity to separate the lighter and heavier solids.
Answer: Somewhat true. Gravity is involved in the settling of solids to the bottom of the tank, but soap scum, grease, etc., will float on water and become part of the scum layer, along with any other materials that are buoyant in water. So there are a couple of mechanisms at work, gravity being one of them.