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These are the basic components of the process however sometimes other components <br /> are required depending upon the type of development being served, and the <br /> requirements of the State or local regulatory authorities. <br /> 4. Additional Treatment Available <br /> A. Sludge Storage- Usually sludge storage facilities are required by regulatory <br /> agencies. These facilities consist of valves added to the sludge return piping <br /> to allow a portion of the activated sludge to be diverted to the sludge storage <br /> tank. The sludge storage tank should be used when the amount of sludge in <br /> the plant becomes so great that it cannot efficiently be settled out and <br /> returned to the aeration tank. <br /> B. Disinfection- Usually the treated effluent, which is discharged from the <br /> clarifier, is required to pass through a disinfection chamber for killing of the <br /> pathogenic bacteria in the effluent. This can be accomplished by either <br /> pumping s chlorine solution into the tank or installing tablet style chlorine <br /> feeders in this tank that allow the effluent to dissolve the tablets in the <br /> effluent. Both of these types of chlorination usually require a contact time of <br /> 30 minutes to allow adequate retention for the chlorine to kill the pathogens <br /> depending on the flow characteristics of the plant. Another type of disinfection <br /> is by using Ultraviolet light modules installed inline with the effluent so that <br /> the flow passes by the light and the UV rays kill the pathogenic bacteria, <br /> which is almost instantaneous. <br /> C. Flow Equalization- Frequently due to larger fluctuations in hydraulic flows <br /> which can be encountered at Schools, for instance, it is necessary to utilize a <br /> tank to equalize out any hydraulic surges. This will allow the proper retention <br /> time in the aeration tank and avoid the wash out the solids in the clarifiers. By <br /> balancing out the anticipated load using pumps and a flow control box this will <br /> allow the treatment plant to achieve the results as it is designed for. <br /> D. Tertiary Filters- Frequently due to more stringent effluent requirements, a <br /> multi-media filter can be used to further reduce the BOD and SS from the <br /> secondary treatment system. The filter consists of dual cells that allow flow to <br /> the system even during backwash cycles. The backwashed water flows into <br /> an integral tank commonly know as a mudwell or surge tank where the <br /> backwash is pumped back to the aeration tank in the secondary system. The <br /> filtered wastewater flows by gravity into the clearwell the system, unless this <br /> unit is followed by a disinfection tank as described above. <br /> pCil"UNI-intio-1-3 <br />