Which of the following puts the secondary treatment of wastewater in the correct order?
bacteria settle in clarifier; aeration tank is churned and bacteria eat- water is flowed into the tank and air is pumped into it.
bacteria multiply and eat waste in settler- water is circulated and air is added to the system; bacteria then are added to the aeration tanks.
bacteria seeded in aeration tank as air is circulated throughout the water- bacteria multiply and eat waste; bacteria settle in clarifier.
clarifier is added to the aeration tanks; bacteria thrive and eat waste- air is added to the end to mix the sludge.

Bacteria seeded in aeration tank as air is circulated throughout the water- bacteria multiply and eat waste; bacteria settle in clarifier.

Secondary treatment of waste water is the process for utilizing the wastewater that are obtain from sewage or other sources to make it suitable for further use. It utilizes physical phase separation to remove settled solids and uses biological process to remove dissolved and suspended organic components. It utilizes specific bacterial strain which are aerobic in nature. These bacteria are seeded into the waste water and they take up energy from oxygen provided to water by inducing oxygenated air to feed upon the organic components present in water. These bacteria multiply and colonize at the bottom of the clarifier.

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds