The Importance in Nutrient Removal in Wastewater
The requirements for nutrient removal are becoming increasingly strict. Municipalities and industrial bodies are now implementing technologies to comply with nitrogen and phosphorus discharge requirements to further implement nutrient removal in wastewater.
The Importance of Nutrient Removal
Environmental: When untreated wastewater returns to the environment, it can cause severe damage without nutrient removal by introducing excess nutrients. Because it can encourage algal blooms, which can lead to a deoxygenation of aquatic environments and block sunlight vitality, excess phosphorous is particularly dangerous. Without nutrient removal, it can kill fish and cause massive damage to the environment. There is also the possibility of having a negative effect on aquatic life (i.e. ammonia levels).
Human Health: Experts believe that excess nutrients in the environment can also pose a health risk to humans, especially when it comes to clean drinking water, which is yet another reason that nutrient removal is so important.
Sources of Nutrients Removal in Wastewater Streams
Industrial production of residual nutrients (product/supplement ingredients)
Phosphate is used in cleaning chemicals and/or detergents
All organics have nutrients and require some form of nutrient removal
Run-off from agriculture
There Are a Variety of Technologies for Nutrient Removal from Wastewater Streams
Biologically For nutrient removal, there are many biological wastewater treatment methods. Specific strains of bacteria and micro-organisms can target specific nutrient compounds and then safely neutralize them.
Physically - Chemically Combining chemical additives with filtration technology can effectively accomplish nutrient removal before discharge. These compounds can then be settled, floated, or filtered from the wastewater stream. There are also technologies that can convert nutrients into a byproduct, like struvite.
Ion Exchange Media and resins are able to recover and precipitate nutrients.
What Technologies for Nutrient Removal can Eliminate Phosphate from Wastewater?
Method for Treating Biological Wastewater
It is possible to use biological processes for wastewaters with high levels of phosphorus. It is important to cultivate a biomass capable of holding between 30-40% and 60% of its phosphorus content.
The biomass can then be removed downstream in clarification or filtration. This biological process reduces the need for physical-chemical processes and saves on chemical costs and extra equipment for optimal nutrient removal.
Based on the effluent requirements, one of several physical or chemical technologies may be required for nutrient removal, specifically to remove orthophosphates. This is to comply with discharge permit limits.
It is possible to remove both phosphorus (and total suspended solids) simultaneously by using iron or aluminum-based salts in the polishing stage. High-rate clarifiers (HAFs), dissolved air flotation unit (DAFs) and disc/drum filter are three common polishing technologies.
For more information on nutrient removal and all things related, check out the rest of our articles on the topic here.