Wastewater Treatment: Primary and Secondary Treatment

Chapter 3 1 Introduction Eutrophication is the result of the presence of nitrogen and phosphorus in rivers, as explained in the given case. These rivers are often called sensitive rivers. These nutrients promote the production of algae, provide food for its growth in an accurate environment, and bring eutrophication. Eutrophication harms ecosystems, resulting in unnecessary changes in aquatic life, extreme oxygen reduction, human and animal health problems, expensive water treatment costs, and destructive entertainment.

At the wastewater treatment facility in New York City, wastewater has undergone five major processes. Primary treatment, primary treatment, secondary treatment, disinfection, and finally sludge treatment. Primary treatment and secondary treatment will remove about 85% - 95% of the contaminants in the wastewater before the treated wastewater is sterilized and discharged to the local waterway. Sludge (a by-product of the process) is digested to stabilize and then dehydrated for disposal. The resulting material (called biosolids) is applied to the land to improve vegetation, or even as a treatment of compost and fertilizer. (See "Processing process chart" on page 16-17)

Secondary wastewater treatment is the third stage of wastewater treatment performed after the primary treatment process. This process involves removing or reducing residual contaminants or growth in the wastewater from the primary treatment process. Typically, biological treatment is the most effective type of treatment for the growth of bacteria or pollutants, so it is used to process wastewater in this process. Tertiary treatment is the next wastewater treatment process after secondary treatment. This step removes stubborn contaminants that can not be removed by secondary treatment. By using a more powerful and advanced treatment system, drainage will be cleaner during wastewater treatment.