PPTAC/2 Planta Tratamento de Água (filtração e troca iônica), Controlada por Computador (PC)

The Computer Controlled Water Treatment Plant 2, "PPTAC/2", allows to study the main principle of the basic operations in the water treatment.

These operations are: depth filtration and ion exchange.

The general objective of the exercises is to achieve the best treated water quality possible. The unit can be used to perform two variations of the specified processes:

• Filtration.
• Filtration and ion exchange.>

The unit is mounted on a floor standing metallic structure.

It consists of two main sections:

• One section is a supply unit with two tanks to store the raw water and the treated water. The raw water part includes a tank and a computer controlled submersible pump to impel the water from the tank to the filter. The treated water part includes a tank to collect the water outlet of each operation in the water treatment plant (depth filtration and ion exchange) and a pump to drive the treated water to wash the filter.
• The other section is the Water Treatment Unit, which is connected to the tanks of the supply unit and consists of a filter and two exchangers.

Raw water is pumped from the raw water part of the supply unit into a filter. The flow velocity in the filter bed can be adjusted. The solids are captured and retained by making the water flow through the filter bed.

Filtered water emerges from the bottom end of the filter and can flow into the second treatment stage or can flow into the treated water tank, depending on the position of the circuit solenoid valves.

In the second stage unwanted ions from the water are exchanged for hydrogen and hydroxide ions by two ion exchangers (cation and anion exchangers). First, water is softened by cation exchange, and then it is desalinated by anion exchange. Finally, treated water flows into the treated water tank.

The solids retained in the filter cause an increase in the pressure loss. The unit allows a backwash to clean the filter and reduce this pressure loss.

The unit includes an acid/caustic circuit to regenerate the ion exchangers. The circuit includes a solenoid valve per inlet of reactive and twelve solenoid valves to divert the flows and circulate the different solutions.

The filter allows to measure the differential pressure in the filter and includes several pressure measuring points along the filter. The values of the pressure (expressed as water column) are measured with a water multi-manometer panel. These values can be used to plot Micheau diagrams.

All the relevant parameters (flow rate, pressure, differential pressure, temperature, conductivity) are recorded by sensors.

This Computer Controlled Unit is supplied with the EDIBON Computer Control System (SCADA), and includes: The unit itself + a Control Interface Box + a Data Acquisition Board + Computer Control, Data Acquisition and Data Management Software Packages, for controlling the process and all parameters involved in the process.