Surface World April 2019 Surface World April 2019 - Page 54

WATER & EFFLUENT TREATMENT pH Correction Pumps and Suction Lances to the dosing pumps enabling them to automatically adjust the speed or frequency that the dosing pumps operate at, meaning that the pH can be very precisely controlled to the desired set-points. The PID control allows our customer to accommodate wide fluctuations in the measured pH value, as well as ensuring that only as much chemical as is required to neutralise the pH between the set-points is dosed into the wastewater treatment tank. Discharge pH Controller The discharge pH controller is another P7687 pH controller taking a signal from a PS90s located in the waste-water or effluent outfall sump. The discharge pH controller constantly monitors the treated wastewater to ensure that it is compliant with the customers consent to discharge agreement. In this particular installation, it’s imperative that the final pH level is logged so the P7687 is continually providing the discharged pH value to the data logger. AODD Transfer Pumps Data Logger The control panel also includes a digital data logger in the form of our new AWE-99 colour touchscreen data logger. control panel which in turn takes it’s signal from the level electrodes. In addition to the level control circuits for the air operated diaphragm transfer pumps, the control panel also houses:- Neutralising pH controller In a pH neutralisation system, having an accurate pH controller designed for industrial usage is crucial. The P7687 combines accurate pH measurement with precision control functionality. The P7687 is part of our new generation of process control instruments with this specific model featuring PID control of pH. As the P7687 is a PID (Proportional, Integral and Derivative) pH controller it provides a signal The AWE-99 along with the larger AWE-141 digital data loggers are capable of data logging inputs from 4-20mA signal, High Speed Counter or a Modbus value amongst many, many, other input signals. In this instance the value from the discharge pH controller is being logged to create a trend graph showing the change in pH over time. All this data is being logged directly to the onboard memory of the AWE-99, the customer also has the option of backing this log up to an external USB drive which can be connected to the front of the AWE-99. In addition - with a built in web-server the AWE-99 can be connected to the customers local intranet, allowing them to view the discharge pH from any device connected to the local network. The AWE-99 digital data-logger allows the customer to log the pH of their final effluent discharge which can then be examined by an external regulatory body so that they remain compliant with their consent to discharge agreement. The AWE-99 data logger fitted to the customer’s pH neutralisation system was supplied complete with 2 additional inputs, meaning that the customer can also log the final effluent discharge flow from a V-Notch tank and the final temperature if required. As a fully expandable instrument, the AWE-99 can be fitted with many further inputs even if the data-logger is already installed and in-situ. Tank Mounting pH Electrode Assembly The tank mounted pH electrode assembly is our PS90s dip mounting pH electrode assembly. Designed to provide continual measurement of the pH in unpressurised vessels, sumps or pits - the PS90s is ideal for this purpose. Utilising a rigid mounting tube with an adjustable mounting flange the PS90s provides precision pH measurements from the PS183-20B pH electrode located at the tip of the PS90s. Given that the customer is using a powerful and accurate pH controller in the P7687 it’s important to pair the pH controller with a precision pH probe designed specifically for industrial usage. This is where the PS183- 20B pH electrode comes in, offering accurate pH measurements in process environments. In addition using the BSP threaded connections the PS183-20B can be easily removed making calibration of the pH electrode simple and straight forward. As with all sealed pH electrodes containing a liquid or gel reference junction, they eventually need replacing as the reference material is consumed. With the PS90s only the pH electrode insert, model number PS183-20B, is replaced, providing our customer with a low cost of ownership as only the pH sensor is replaced, the riser tube and precision electronics can be used over and over again. The rigid mounting tube of the PS90s ensures that the pH electrode can continually provide accurate pH measurements to the pH controller, even when the tank mounted high speed mixer is operational. High Speed Industrial Mixer By incorporating a high speed industrial mixer into the wastewater treatment tank, we can improve both the chemical efficiency CONTINUED ON PAGE 56 52 APRIL 2019 twitter: @surfaceworldmag