Ponds and lagoons are some of the world’s oldest tools for wastewater treatment and continue to be used today in developing and developed countries. They’re constructed by impervious material to prevent the infection of surrounding groundwater by toxic waste. The wastewater sent into the pond or lagoon uses bacteria and oxygen to break down organic materials into carbon dioxide or methane gas. It’s a low-maintenance wastewater solution that relies on natural processes for effective results. There are two commonly used domestic water waste solutions. They are stabilization ponds and facultative lagoons.
Stabilization ponds are aerobic. They require oxygen throughout the body of water. Water is held within treatment areas. The detention time of the wastewater averages thirty days. In the United States, laws dictate how long the water must be detained for treatment. During that time, aerobic bacteria and air are circulated through the treatment area. The bacteria uses the oxygen to break down waste and create carbon dioxide. Solid wastes that cannot be treated with the bacteria become sludge and are typically pumped into a second system.
Facultative lagoons are different in that they’re aerobic on top but anaerobic on the bottom. This is often a more effective treatment for industrial areas where water output contains large amounts of solid matter. Due to the increased amount of solid matter in facultative lagoons, they’re deeper. The bottom of the lagoon stores the water undergoing anaerobic treatment. Anaerobic refers to the process of treating the water without oxygen. Instead of bacteria that requires oxygen, anaerobic bacteria transforms waste into carbon dioxide and methane gas. Once again, waste that is not broken down is called sludge. However, facultative lagoons have less waste output than ponds.
These two wastewater treatment options can and are used in conjunction. Anaerobic lagoons are used for the pretreatment process and they then release the water into the stabilization pond.
While these wastewater solutions do require less oversight, some maintenance does ensure they’re operating correctly and efficiently. Wastewater treatment companies can clean out ponds and lagoons and remove built up silt. As long as the water remains contains contained, users of natural wastewater methods like ponds and lagoons can mostly leave natural processes to comb through the waste and leave behind reusable irrigation water or rejoin with surface water.