Ways to Improve and Modify Activated Sludge Treatment System

There are several ways incorporating different designs and technology in order to improve the activated sludge system so that wastewater treatment can be more effective. Listed here are the number of modifications which can be made to existing plant treatment design. Let’s consider and weigh several options available.

Contact StabilizationFew of the main reasons whereby there are problems related to sustaining healthy activated sludge growth is due to temperature shock, sudden pH changes and also change of COD load for the incoming wastewater feed. Thus in order to prevent this condition, all these can be overcome using contact stabilization method in order to modify the system whereby there are two separate tanks or one single tank with different compartments which are constructed specifically for this. The resulting stabilized activated sludge is mixed with the wastewater coming from the contact tank and the resulting mixed liquor is left to settle in a settling basin in another tank.

Conventional plug-flowFeed to the aeration tank are properly mixed by diffused aeration or by using mechanical aeration which will allow better mixing and good distribution of oxygen throughout every corners of the tank. With better aeration this will help towards absorption and oxidation of organic matter by the microorganism present in the activated sludge system. The solid will then be separated in another settling tank.

Taped AerationTaped aeration is a different design based on the conventional plug flow system. In this application, varying aeration rates are applied by adjusting the aerator motor speed or air feed going to the wastewater and these will depend on the biological oxygen demand required by the process. Usually taped aeration will be applied using air diffusers spread evenly throughout the tank length whereby higher amount are available at the head end of the aeration system and lowers as the mixed liquor reaches the effluent end discharge.

Step-Feed Activated sludge aerationIncoming wastewater going to the aeration pond can be introduced at several points and this is the basis of the step-feed aeration system. The purpose of doing this is to equalize the F/M ratio and thus allows a better and more efficient distribution system and prevents high oxygen demand only at one single location (usually at the feed point). For this system to be implemented, several built-in channels can be constructed to divert the incoming wastewater running parallel going to different feed points around the aeration pond.

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