Aeration Systems

Aeration Systems

Flexcap Aeration Systems are utilized in four primary processes:

• Aerobic Digesters
• Channel Aeration
• Equalization Basins
• Sludge Holding Tanks

A typical system starts with a flange at the top of the tank and includes a drop pipe with expansion joint, air main and laterals with Flexcap diffusers. We also provide adjustable pipe supports, gaskets and flange hardware.

Due to exposure to sunlight, the drop pipe is Sch 10 stainless steel. The remainder of the pipe is Sch 80 PVC. Pipe supports and hardware are 304 stainless steel. There is no field cutting or gluing required.

Without a comprehensive model of the aeration system, energy savings calculations comparing
coarse with fine bubble aeration systems are often skewed by not including increased back
pressure that occurs in fine bubble systems or taking credit for improved control of dissolved
oxygen levels as part of a diffuser upgrade. This can be addressed by separating the calculations
for each of these improvements.

Another important function of the aeration equipment is to provide adequate mixing in the tanks to prevent solids from settling. This is an important aspect that is often overlooked when aeration systems are reviewed for energy saving opportunities.

The basis of our system designs is “Mixing Requirements”. Water Environment Federation Manual of Practice No. 8 recommends 20 to 40 cfm/1,000 cu ft of air to ensure adequate mixing. We design our systems for 30 cfm/1,000 cu ft.

TYPICAL AERATION TANK MIXING REQUIREMENTS

Some facilities have successfully used a combination of high efficiency mixers (.23 hp/1000 ft3)
with aeration equipment to optimize their aeration process. The mixers can be used during
periods when mixing energy requirements control to maximize treatment efficiency while
minimizing energy demand.

Improvements on the degree of treatment and the consideration of nitrification have resulted in increased requirements for aeration systems. Oxygen transfer constitutes a Major Operating Cost for most biological wastewater treatment systems. Many researchers contend that the potential for efficiencies and economic design capabilities in activated sludge processing have not yet been reached. It has also been suggested that oxygen transfer limitations restrict the design of plants beyond their present acceptable loading limits.

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De-Gassing Process

WATER TREATMENT DE-GASSING PROCESS

Degassification is one of several steps that occur at a water treatment processing plant. Without the degassification process, dissolved oxygen and carbon dioxide can react with metal surfaces and promote corrosion. De-gassing releases these dissolved gases from the water, thereby helping to protect contact surfaces of the wastewater and water treatment processing equipment and storage tanks.

WASTEWATER TREATMENT DEGASSIFICATION

Wastewater treatment plants consist of ammonia and hydrogen sulfide dissolved in water, along with various trace contaminants, such as carbon dioxide, phenol and cyanides. Designed for ammonia concentrations between 0.3 and 6.0 Wt % and hydrogen sulfide concentrations between 0.3 and 10.4 Wt %, typical wastewater treatment facilities can also handle water with high ratios of ammonia to hydrogen sulfide or high carbon dioxide content.

One of the four processing steps in the wastewater treatment process is “Degasification”. The other three are acid-gas stripping, ammonia stripping and ammonia purification and recovery.

The wastewater degasification is generally the first process initiated. The goal of de-gassing the waste-water is to remove any dissolved hydrogen, methane and other light hydrocarbons. The release of acid gas and possible air pollutants are minimized. After the degassification occurs, the sour water is pumped to an off-site storage tank for dampening the flow rate and composition changes. During storage, the tanks further assist in removing entrained oil and solids.

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