Pilot Plant

Sedimentation Tank

Overview

Two parallel sedimentation tanks are connected in series with the flocculator at the The pilot plant. The sedimentation tank will be a verticle flow style tank and will only use a sludge blanket as its removal mechanism. This tank will be the first time that an AguaClara team has used a sludge blanket instead of plate settlers. As with other AguaClara designs, the tank will be run by the elevation head in the flocculator tank and will not require electricity. There are several design restraints due to the current set up at the pilot plant. There are 37'' of available water head  at the end of the floculator which are available for our use. The piping connection between the flocculator tank and sedimentation tank also cannot have a shear value that excedes the max shear in the last baffle section ( GMax= 48.826 /s), or else the flocs made in the last section will be broken up.The flow through the sedimentation tank has been limited to half of the flocculator tank flow so that it will be possible to construct a second tank sometime in the future to handle the other half of the flow. ideally this second tank would only use plate settlers so that we could make a comparison between a sludge blanket and plate settlers.  tanks allow us to further examine the efficiency of the process in the AguaClara design. Sedimentation tank design needs to be optimized to acheive our overriding goal of consistent production of water, under 1 NTU. Testing will include not only the traditional lamella design of sedimentation tanks but also the alternative floc blanket based sedimentation tank designs. These two processes are being tested side by side in parallel sedimentation tanks. One tank combines of lamella and sludge blanket technology and is compared to the other which only uses a sludge blanket to treat water.

There are several concerns with the implementation of floc blankets into the AguaClara treatment plants. Some of these include: the length of time it takes to develop a fully functional floc blanket, the reliability of the floc blanket, and when and how excess sludge in the floc blanket is drained. To read more about these concerns, click here. However, one of the huge benefits to the pilot plant as opposed to a regular research lab is that water source is natural! The incoming water is taken from Fall Creek and therefore contains natural organic particles. This enables influent conditions to be more representative to those in Honduras.

Sedimentation Sludge Blanket Tank goals and meeting minutes

Design

Current dimensions of the sedimentation tank, and the calculations used to determine them can be found here.

Methods and Research

Some of the methods that are being used at the pilot plant are compiled here.

Results

Sludge Blankets at Different Upflow Velocities

The results of trying to form a sludge blanket at various upflow velocities in an otherwise empty sedimentation tank are shown here.

The Formation of a Sludge Blanket

Observation of how a sludge blanket is formed and how well the control sedimentation tank operates are shown here.

Construction History

The construction history of the sedimentation tank is available on this page.

Maintenance and Tips

For help on keeping the sed tanks and related components working well, or for some tips on experimenting, look at maintenance and tips.