Solutions for Ammonia Removal in Wastewater

Published: 22nd April 2010
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The problem with ammonia in wastewater has become a major concern throughout the world, particularly in United States. About half of the states in U.S, including the District of Columbia, have followed the rules in pursuant to EPA's 1999 water quality criteria for ammonia removal.

From plastics to explosives, ammonia makes up most of the products used in different industries. Ammonia discharged from factories or industrial plants may run through the sewage systems known as wastewater. High concentrations of ammonia are toxic to humans and animals that is why sanitation engineers and government are working closely in removing ammonia from wastewater. Untreated volumes of ammonia in wastewater can disperse on the air, and affect those who have inhaled the chemical. This can also bring serious illnesses and skin disorders due to physical contact or consummation of ammonia.

There are various wastewater treatment technologies used nowadays in removing ammonia from wastewater. Here are some of the common treatments for ammonia wastewater removal:

Biological Nitrification

Biological infiltration is a water treatment process utilized to convert ammonia into nitrate using aerobic autotrophic bacteria. The biological infiltration uses two types of bacteria: the bacteria that oxidise ammonia to nitrite (nitrosomonas) and the bacteria that oxidise nitrite to nitrate (nitrobacter). Both types of autotrophic bacteria need proper biomass, right environment, and sufficient air to treat biochemical oxygen demand. Nitrification requires ample amount of oxygen to carry out the process.

Conventional Activated Sludge

There are various systems used in conventional sludge treatments such as complete-mix, plug flow, and step feed treatment. All of these types have the same frame for aeration and clarifier. Ammonia is converted through the aeration basins.

This treatment is proven effective in treating different types of wastewater, and easier to operate than other types of treatment. However, this type of treatment requires higher capital because the aeration basins and clarifiers are constructed from expensive concrete materials.

Extended Aeration

The extended treatment process is almost the same as the conventional activated sludge treatment because it uses the latter's exact mechanical equipment such aeration basins, clarifiers, return activated sludge, and waste activated sludge process. The only dissimilarity is that extended aeration requires longer hydraulic and solid residence during the process.

Longer hydraulic and solid residences enhance the quality of wastewater produced from this treatment. With sufficient oxygen, extended aeration treatment can provide high levels of biological nitrification. One disadvantage of extended aeration is the cumbersome equipment needed to achieve longer hydraulic and solid residence. People on tight budget will not consider buying this equipment because it is pricey.

Membrane Bioreactor (MBR)

The membrane bioreactor has three main components: anoxic basins, pre-aeration basins, and the MBR basins. The treatment begins by filtering the raw wastewater through the fine screen, and the refined fluid is then sent to the anoxic basin, and lastly to the MBR basins. The membranes located in the MBR basins push the effluent for disinfection prior to discharge.

The membrane bioreactor treatment is considered to be one of the effective solutions because it produces high effluent quality without extensive clarification or filtration and promotes total nitrogen removal. Moreover, if the two previous treatments are expensive, MBR is much more costly to own and maintain. The maintenance and replacement for the equipments require attention, and the cost to meet the operation is a bit pricey.

There are other water treatment products available, but it is highly recommended to consult an engineer before opting for a treatment.

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