Water purification plant control system

You are working as a design engineer at a company that specializes in water treatment plants. You have been given the task to develop the control system software for the 1st stage dosing system of a water purification plant for a manufacturing company. Dirty water, as result of the manufacturing processes, is pumped into a settling tank to allow impurities to settle. To promote the settling process a flocculant must be added to the water in the Mixing Tank before the water enters the Settling Tank. The amount of flocculant required is directly proportional to the amount of impurities in the water. The amount of solids in the water can be measured using a LDR sensor, the amount of impurities reducing the amount of light passing through the water. There are 4 solenoid valves that control the amount of flocculant that is added to the dirty water in the Mixing Tank. The amount of valves to be opened depends on how clear the water is. If the water is clear, all valves would be closed and as the amount of impurities in the water increases so more valves will be opened. The control system must use a PIC16F88 microcontroller and the development work must be done using the Matrix Multimedia development board.