SBR (Sequencing Batch Reactor) Systems

A SBR is a fill-and-draw activated-sludge treatment system, involving a single complete-mix reactor. The unit processes involved in the SBR and conventional activated sludge system are identical. Aeration and sedimentation are carried out in both systems. However, SBR’s advantage lies in the fact that it accomplishes equalization, aeration and settling in a timed sequence, in a single reactor basin, whereas a conventional continuous flow process requires multiple structures and extensive pumping and piping systems.

SBR systems usually have five steps that are carried out in sequence:

• Step 1: Fill

• Step 2: React (aeration) 

• Step 3: Settle (sedimentation/clarification) 

• Step 4: Draw (decant) 

• Step 5: Idle 

SBR Systems

Sludge wasting is not included as one of the five basic process steps because there is no set time period within the cycle dedicated to wasting. The amount and frequency of sludge wasting is determined by performance requirements. Sludge wasting usually occurs during the idle phase. Another unique feature of the SBR is that there is no need for a return activated-sludge (RAS) system because settling and aeration occur in the same tank.  

Salient Features 

High Removal Efficiency 

All wastewaters commonly treated by conventional activated sludge plants can be treated with SBRs. The BOD removal efficiencies are as high as 90-95%.

Process Flexibility 

The fact that the process involved with SBR is very flexible enables it to achieve any combination of oxidation, nitrogen reduction, and phosphorus removal. Reduction of these constituents can be accomplished with or without chemical addition by changing the operation of the reactor. High removal efficiency makes SBR capable of reducing phosphorus to less than 0.5 mg/l and nitrogen to less than 1 mg/l. 

Siting Flexibility 

SBR systems are generally used for small communities where land area is limited. These plants have low-space requirements and have hardly any or no smell problems. This makes them very suitable for installation virtually anywhere – be it an apartment complex, hotels/motels and public parks etc. The designs can be further attenuated to free it of noise nuisance. 

Modular Expansion Capability 

Our systems based on SBR technology are designed in such a fashion so as to make it open to modular expansion while optimizing the use of original plant equipment. 

Reduced Capital Costs 

Capital Costs are greatly reduced because of the following:

• No settling tank and related mechanical equipment;

• No return sludge pump house and pumps; and

• Reduced interconnecting piping and no return sludge piping.  

Reduced Operation & Maintenance Costs 

• SBR systems customized by us involve low O&M costs;

• Simplistic design;

• Automated PLC controls

• Ground level servicing of all equipment

• Very low power consumption

• Low operator requirement (a periodic checking of the PLC panel is all what is required)

Design Criteria for SBR Systems :