Wastewater Treatment

The Activated Sludge Process (ASP) is an inherent biological wastewater treatment method, mainly for secondary treatment under aerobic condition (with dissolved oxygen). It involves introducing activated sludge into wastewater to rapidly break down impurities. This process includes aeration and agitation in an aeration tank, followed by settling in a clarifier, The Activated Sludge Process (ASP) is an inherent biological wastewater treatment method, mainly for secondary treatment, under aerobic condition (with dissolved oxygen). It involves introducing activated sludge into wastewater to rapidly break down impurities. This process includes aeration and agitation in an aeration tank, followed by settling in a clarifier. The settled sludge can be returned as Return Activated Sludge (RAS) to the aeration tank to maintain the right microorganism balance or disposed of as Waste Activated Sludge (WAS). 

Sludge age, representing the duration microorganism or sludge or particles are retained in the aeration tank affects microorganism behaviour and the treatment quality. 

Influent wastewater is monitored for parameters like COD, BOD, pH, alkalinity, flow rates, and contaminants, which collectively impact plant efficiency. 

The extended aeration process stands out among activated sludge variations as it combines sludge disposal with wastewater purification. It efficiently treats small-volume domestic and industrial waste without the need for primary sedimentation tanks. An extended aeration period facilitates aerobic digestion of most biological sludge. 

In the process, organic waste is partially oxidized and synthesized into new bacteria cells in the first stage. The subsequent phase involves self-oxidation of biological cells, producing energy. With low organic loads, high biological solid concentrations, and prolonged aeration, this method removes approximately 98% or more of organic material, converting it into carbon dioxide, water, or new biological solids. 

This approach ensures a stable operational environment, high efficiency, cost-effective construction, and simplicity. It also employs a longer sludge age compared to other aerobic systems. 

Carbon, nitrogen, and phosphorus are significant nutrients for aquatic life. However, excessive levels of these nutrients pose serious problems. Wastewater treatment facilities must adhere to strict nutrient effluent limits, covering phosphorus, nitrogen, carbon, and various micronutrients commonly found in wastewater. Nutrient-rich wastewater can lead to eutrophication, ammonia toxicity, and nitrate contamination of groundwater. Nutrient removal in wastewater is crucial to reduce oxygen demand in receiving water bodies, protect aquatic ecosystems, prevent eutrophication, and ensure public health. 

Both nitrogen and phosphorus can be biologically removed. Nitrogen can be eliminated through processes like nitrification-denitrification or deammonification. Biological phosphorus removal is possible because microorganisms require and use phosphorus for energy transfer and cellular components. In wastewater, most phosphorus exists as orthophosphate, polyphosphate, and organic phosphate. During biological treatment, microorganisms typically convert polyphosphate and organic phosphate into readily assimilable orthophosphate. 

The 5-stage Bardenpho treatment plant, known as the Bardenpho System, represents a specific design within the realm of activated sludge wastewater treatment. It is a prominent and accepted choice for Biological Nutrient Removal (BNR).

The Bardenpho treatment process is a highly efficient and widely adopted approach for the removal of organic matter, nitrogen, and phosphorus from wastewater. This method incorporates anaerobic, anoxic, and aerobic zones, making it particularly effective for treating diverse wastewater streams, including those with elevated nutrient concentrations. 

A Nitritation-Deammonification (ND) system is an advanced wastewater treatment method that combines two distinct biological processes: nitritation and deammonification, to remove nitrogen compounds efficiently. This energy-efficient approach eliminates the need for traditional nitrification, which converts ammonia to nitrate, a less desirable form of nitrogen that can contribute to eutrophication in natural water bodies.

The ND process is particularly suitable for wastewater treatment plants with a high-strength ammonia load, such as industrial or anaerobic digester dewatering stream of municipal wastewater facilities. It provides benefits like reduced energy consumption, lower sludge production, and a smaller footprint compared to conventional nitrogen removal methods.

Implementing a Nitritation-Deammonification plant requires careful design, optimization, and monitoring to ensure optimal performance. Process control parameters, such as dissolved oxygen, pH, nitrite-nitrate levels and temperature, must be managed to promote the growth of specific bacteria involved in nitritation and deammonification.