Surface World November 2019 Surface World November 2019 | Page 56

WATER & EFFLUENT TREATMENT
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.
pH Correction Pumps and Suction Lances
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
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NOVEMBER 2019
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