Computer Control of Sludge Fermentation : Process Monitoring and Data Treatment

Summary

The process monitoring and data treatment systems of a pilot fermentor unit are described. The main purposes of the data system are : acquisition of experimental data, their reduction in a easily and quickly understandable form, development of computerized control systems for waste treatment.

The fermentor unit consists of three separate vessels with individual sensors and control elements. The following elements compose the system : a multiplexer, a desktop computer and a printer plotter. The multiplexer is interfacing the system to the fermentor both for data input and control output. The desktop computer acts as a system controller. Hardcopy output is from the printer plotter.

Following features are highlighted:

• Scanning of up to 36 data channels either sequentially or selectively;

• Software smoothing of noisy signals;

• Foreground-background operation due to a local microprocessor at multiplexer level;

• Live keyboard allowing operator intervention during fermentation run

Programms referenced are:

• “Input” : data acquisition and continuous display on CRT

• “Output” : data deduction and logging

• “Opern” : a programfragment that derives control parameters from the response of the system to small induced changes

• “System” : supervision program fragment checking system status and some error conditions

• “Plottn” : providing graph output, with autoscaling and labelling.

Current research is directed to software development for the optimisation of fermentation processes on a heuristic basis.