Activated Sludge Process

Extended aeration is aerobic biological treatment process used in wastewater treatment. This process is principally modified version of most commonly used and proven technology i.e. activated sludge process. Extended aeration systems are simpler in construction and operation. The wastewater is brought directly to the aeration basin after screening and grit removal.

In aeration basin the aeration is carried out for extended period of time thus mineralizing the sludge solids sufficiently hence the sludge produced is completely digested. Extended aeration is a method of sewage treatment using acclimatized active biomass, the oxygen for bioprocess is provided from mechanical aeration system of blowers and fine bubble diffusers. The suitable ratio of food to microorganism (F : M) is maintained for effective process operation. The microorganisms maintained in reactor carries out digestion of oxygen demanding impurities present in wastewater and hence the treated water is with very low concentration of biological and chemical oxygen demand. The clarifier or tube settler downstream is used to carrying out solid- liquid separation, settled sludge at bottom of reactor is partly recycled back for process, excessive sludge is sent for sludge dewatering treatment.

The ability of absorbing flow and qualitative shock loads due to higher detention time makes it preferred and reliable treatment process. This type of treatment process is very commonly used worldwide and in major industrial applications of wastewater/ effluent treatment.

The Sequencing Batch Reactor (SBR) is a derivative of activated sludge process designed to operate under non-steady state conditions. Like extended aeration or other activated sludge process it involves the biological process, microorganisms and mechanical aeration system for aeration along with air distributors and diffusers. However the major difference in involved is in operation of treatment which is carried out in batches in cyclic manner. In SBR configuration all related processes of Aeration, Settling, Decanting are carried out in same basin and eventually this reduces construction cost which is very essential in larger systems. The most important component of SBR process is decanting system. The various type of decanters are used for process like Floating gravity type, rake arm type, floating funnel type and slotted pipe type decanters. The process is operated in batch manner and hence it is vary suitable for industrial wastewater and high flow domestic wastewater. The added advantages are it provides BNR ( biological nutrients removal) and completely digested sludge which makes sludge treatment process easier.

SBR is modern wastewater treatment system which involves use of automation in operation. The control of cyclic batch operation is programmed in PLC or SCADA. The instruments involved in process helps to transmit appropriate signal and control the system. The automation of system reduces the number of operator skill and attention requirement and hence improves output quality of treated effluent.

Sparkle offers unique design of sequential batch reactor decanting system which involves simple automation and gravity based decanting system. The power requirement for decanting operation is eliminated in this design.

Advantages: economical construction due to single tank design. The system can absorb higher shock loads. Provides 95-98% removal in BOD.