4.9 Nitrogen Removal

Why is nitrogen removal important in wastewater treatment?

• To enhance the color of treated water

• To reduce the risk of explosive reactions

• To prevent eutrophication and water pollution

• To increase the water's acidity

What is eutrophication?

• Decrease in nutrient levels in water bodies

• Increase in oxygen levels in water bodies

• Excessive growth of aquatic plants and algae due to high nutrient levels

• Reduction in water temperature

Which form of nitrogen is typically found in wastewater and needs to be removed?

• Nitrogen gas (N2)

• Nitrate (NO3-) and Ammonium (NH4+)

• Nitrous oxide (N2O)

• Nitric oxide (NO)

What role do bacteria play in nitrogen removal processes?

• They produce nitrogen gas

• They convert ammonia to nitrate and nitrite, and then to nitrogen gas

• They break down nitrate into ammonia

• They have no role in nitrogen removal

What is the primary source of nitrogen in wastewater?

• Industrial chemicals

• Soil erosion

• Human and animal waste

• Volcanic activity

Which type of nitrogen removal system utilizes an aerobic zone followed by an anoxic zone and then an anaerobic zone in the same reactor?

• Conventional activated sludge

• Trickling filter system

• Moving bed biofilm reactor (MBBR)

• Integrated fixed-film activated sludge (IFAS)

What is the principle behind the Anammox (Anaerobic Ammonium Oxidation) process for nitrogen removal?

• Ammonia oxidation in the presence of oxygen

• Ammonia oxidation without oxygen

• Nitrate reduction to nitrogen gas

• Nitrite reduction to ammonia

Which nitrogen removal technology relies on the use of specific bacteria that can convert nitrate to nitrogen gas under anoxic conditions?

• Deammonification

• Carbon adsorption

• Electrodialysis

• Ion exchange

In which type of nitrogen removal system does water flow over a microbial-covered media, promoting biological nitrogen removal?

• Rotating biological contactor (RBC)

• Activated sludge process

• Membrane bioreactor (MBR)

• Trickling filter system

What is the primary purpose of nitrification in wastewater treatment?

• To convert ammonia (NH₃) to nitrate (NO₃⁻)

• To convert nitrate (NO₃⁻) to ammonia (NH₃)

• To remove suspended solids from wastewater

• To disinfect wastewater