What is the recommended treatment process for effective management of wastewater in facultative lagoons?

The recommended treatment process for effective management of wastewater in facultative lagoons involves both aerobic and anaerobic processes. In these lagoons, the upper layer of water becomes aerobic due to the presence of sunlight, which promotes the growth of algae and other microorganisms that utilize the oxygen produced to break down organic matter. The lower, deeper layers of the lagoon typically become anaerobic as they do not receive sufficient oxygen. This layered system allows for a combination of biological processes that effectively treat wastewater.

Aerobic processes are essential for the breakdown of organic compounds, while anaerobic processes help in the stabilization of the sediment and the degradation of materials that cannot be easily decomposed in the presence of oxygen. The interplay between these two processes ensures that organic pollutants are effectively reduced while also facilitating nutrient cycling within the ecosystem of the lagoon.

The other options – filtration only, chemical treatment only, and mechanical agitation – do not adequately describe the multifunctional nature of facultative lagoons, which rely on natural biological processes in a stratified environment for the efficient treatment of wastewater.