Stages Of Wastewater Treatment

Wastewater treatment is closely related to the expectations set for the effluent quality. The wastewater treatment processes are designed to achieve improvements in the quality of the wastewater. This treatment process may reduce suspended solids, which are physical items that are a clogging hazard. Biodegradable organics can also be reduced in this treatment, these fuel microorganisms who then consume oxygen that is needed by the fish and can cause “dead zones” in local rivers. Pathogenic bacteria and other disease causing organisms are reduced or eliminated, this is used for water that comes in close contact with humans and/or drinking water. Lastly this treatment process may reduce certain nutrients, like nitrates and phosphates and that’s …show more content…
The first level is referred to as the Primary Treatment, or Mechanical. This level is made to remove the suspending or floating solids from raw sewage. The mechanical part of this level would refer to the screening or sedimentation of the process. Many advanced wastewater treatment plants in industrialized countries have started with this primary stage and then adds more treatment stages beyond this one as needed to maintain their load. This stage will be discussed more later in this paper. The next Stage of treatment is the Secondary Treatment, or Biological. This stage takes care of the dissolved organic matter that escapes the primary stage. This is done by microbes consuming organic matter which is then converted to carbon dioxide, water, and energy for their own growth and reproduction. The biological process is then followed by other settling tanks to remove any leftover suspended solids. The last stage of this treatment process is the Tertiary Treatment stage. The tertiary treatment stage can remove more than 99% of the remaining impurities, making the water that come after this stage almost drinkable. This stage is extremely complex, involves a number of experienced operators, and involves specific equipment and technology. This stage is the one that removes the addition phosphorus and nitrogen (Introduction to …show more content…
Grit is sand and any other heavy particle matter, for example seeds or coffee grounds. Grit settles to the bottom of the wastewater when its velocity is reduced and can get stuck to walls of piping or equipment, possible causing clogs. If the grit isn’t removed in this stage and gets in the primary settling tanks, then it can cause abnormal abrasive wear on the mechanic equipment and sludge pumps. Grit processing through dewatering is critical to actual grit removal and protection of equipment. The quality of grit depends on local sewer conditions, age, and soil carried with infiltration. Just like screening, grit quantities are not monitored by plant operators (Hammer, Hammer Jr.