Report on Project of Crossflow Microfiltration Unit

Report on Project of Crossflow Microfiltration Unit

Kareemah Abdullah and Samantha Park

For our term project we went into RPI info NCSA Mosaic to find a project "EMILY" at the University of Natal in Durban. We read and analyzed this research project in order to see how we could relate it to RPI's courses, labs, and/or research programs. We also wanted to find out how and if this project could enhance the existing RPI curriculum.

We read about the development of a cross-flow microfiltration unit. The researchers are V.L. Pillay and C.A. Buckley. The purpose of the project is to develop and demonstrate a cross flow microfiltration unit for the improvement of anaerobic digestors at waste water treatment works. Some courses that this research project might directly deal with is Separation Processes, Chemical Process Control or may be implemented as a Chemical Engineering Senior Lab for Environmental Engineers. This would be an excellent opportunity for environmental engineer majors to get hands on experience in real environmental situations since it is a current problem that they currently do not have enough labs for them.

The experimental studies conducted at the Durban Corporation's Northern Waste Water Treatment Works (NWWTW) shows that anaerobic digestor's performs much better by coupling a "cross-flow microfiltration (CFMF)" unit to the digestor. By coupling a CFMF unit to the digestor the liquid resistance time (LRT) is decoupled from the solids resistance time (SRT). This enables the volumetric throughput of the digestor to be increased while still maintaining the necessary solids residence time.

The coupled process has the "direct advantage" of existing digestors which may be operated at throughputs in excess of their current maximum values. In addition there would be significant "indirect advantages to upstream and downstream unit process.

The "economic feasibility" of the coupled CFMF/digestor process was assessed, by comparing the cost of the coupled CFMF/digestor system to the cost of conventional treatment equipment that would yield a similar volatile solids destruction and final effluent solids concentration.

The next stage in the development of the coupled CFMF/digestor process is to investigate various other aspects concerned with the long term viability, reliability and operability. The major aspects are as follows:

It would be necessary to construct a full-scale CFMF unit in order to address the aspects referred to above. The full-scale unit would thereafter be operated on a continuous basis, to demonstrate the reliability of the process.

The way that this project may be applicable to Rensselaer's curriculum is to employ it as a senior lab. This would be an excellent program for the environmental engineers. One good experiment is for senior engineering students to consider the performance of anaerobic digestors before the unit, then reasearch and analyze the performance of the unit after the installation of a cross flow microfiltration unit. The students could observe the importance of cross flow in the unit. They would also come to fully understand microfiltration as it applies to industry. This might also be very educational as a computer program: "The study of microfiltration and cross flow on a digestor" or "The study of fluid dynamics in flow distribution". Maybe one computer exercise can show that if the biomass concentration in the digestor is increased, there would also be an increase in the viscosity of the digestor contents. As stated before this is a very important aspect when considering the flow distribution in the digestor.

This would also be a good topic on our class Biochemical Engineering for graduates since this is a topic on microfiltration. This is not ideal for an undergradates because this deals with topics that we, as undergraduates did not learn yet. Also this would be an interesting research project for a biochemical professor or an environmental professor.


Tue DEC 5 15:22:13 EDT 1994