The document outlines the design and implementation of an automated neutralization tank for treating wastewater from research labs at the University of Zambia. It discusses the system's objective to control the pH levels of effluent with minimal human intervention, detailing relevant components, methodology, and applications of pH control across various industries. A thorough literature review is included, alongside acknowledgments and the project's personal declaration.

1. THE UNIVERSITY OF ZAMBIA
SCHOOL OF ENGINEERING
DEPARTMENT OF ELECTRICALAND ELECTRONICS
ENGINEERING
NAME: MUKOSA MUSAMA MOFFAT KELLY
COMP#: 14054761
COURSE: EEE5014
SUPERVISOR: DR HIMUUNZOWA G.
TITLE:
DESIGN AND IMPLEMENTATION OF A NEUTRALISATION TANK FOR WATER
WASTE FROM RESEARCH LABS
[2019]

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DECLARATION
I hereby declare that this project report is as a result of my own work through
thorough research and consultations I made during the time of this project which
started in February in 2019.
MUKOSA MUSAMA KELLY MOFFAT (14054761)
Signature: .................................................................... Date: / 10 /2019
SUPERVISOR: Dr HIMUUNZOWA G.
Signature: .................................................................... Date: / 10 /2019

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ABSTRACT
The main purpose of this project is to design the automatic control system for the
neutralization tank which will by controlling the neutralization of the effluent from
the laboratories and industries with minimal human interaction. The control system
will be able to measure the pH level of the effluent which enters the tank and
neutralizes it then discharged and stored for reuse.

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ACKNOLEDGEMNENT
I would like to thank everyone who helped during this project and all those who
made it possible for me to complete my project. And also, not forgetting my
supervisor for guidance rendered to me during the course of this project.

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LIST OFABBREVIATIONS
S1/LS1 LIQUID LEVEL SENSOR NUMBER 1
S2/LS2 LIQUID LEVEL SENSOR NUMBER 2
PLC PROGRAMMABLE LOGIC CONTROLLER
DC DIRECT CURRENT
I/O INPUT / OUTPUT
CPU CENTRAL PROCESSING UNIT

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TABLE OF CONTENTS
Page
DECLARATION i
ABSTRACT ii
ACKNOWLEDGEMENT iii
LIST OF ABBREVIATIONS iv
TABLE OF CONTENTS v
LIST OF FIGURES vi
LIST OF TABLES viii
TABLE OF CONTENTS
1.1.0 INTRODUCTION 2
1.1.1 THE REACTION 3
1.1.2 NEUTRALISATION TANK 3
1.2.0 APPLICATION OF pH LEVELS 5
1.2.1 AGRICULTURE 5
1.2.2 BREWING 5
1.2.3 CORROSION 5
1.2.4 DAIRY INDUSTRY 6
1.2.5 DYEING 6
1.2.6 ELECTRICAL EQUIPMENTS 6
1.2.7 FERMENTATION 7
1.2.8 FLOUR MILLING 7
1.2.9 GELATIN AND GLUE MANUFACTURING 7
1.2.10 JAM AND JELLY MANUFACTURING 8
1.2.11 METAL FINISHING 8
1.2.12 NEUTRALISATION 9
1.2.13 SEWAGE 9
1.2.14 SWIMMING POOL 9

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1.2.15 WATER 10
1.4.0 OBJECTIVES 10
1.5.0 PROBLEM STATEMENT 11
2.1.0 LITERATURE REVIEW 12
2.2.1 AUTOMATION CONCEPT. 13
2.2.2 PROGRAMABLE LOGICAL CONTROLLER 14
2.2.3 pH SENSORS 15
2.2.4 PH MEASUREMENT 17
2.2.5 SOLENOID VALVE 18
2.2.6 DC MOTOR 19
2.2.7 LCD DISPLAY 19
3.1.0.0 METHODOLOGY 20
3.1.1. DESIGN 20
3.1.2 SYSTEM COMPONENT DESCRIPTION 22
3.1.2.1 SOLENOID VALVES. 22
3.1.2.2 PROGRAMMABLE LOGIC CONTROLLER 25
3.1.2.3 FILTER MEMBRANE 29
3.1.2.4 PH SENSORS 29
3.1.2.5 LEVEL SENSORS 29
3.1.2.6 DC MOTOR 29
3.1.3.0 Control System Implementation 30
3.1.3.1 Flow Chart 32
3.1.3.2 SENSOR IMPLEMENTATION 33
4.1.0.0 SIMULATION AND RESULTS 36
5.1.0.0 CONCLUSSION 51
5.2.0.0 RECOMMENDATIONS 52
APPENDICES 53
PROGRAM 53
ZABS BACTERIOLOGY 56
PH VALUE OF KNOWN SUBSTANCES 57
REFERENCE 58

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LIST OF FIGURES
Fig.2.1: Example of a ladder program 13
Fig.3.1 FLOW CHART 19
Fig.3.2. Solenoid schematic circuit 21
Fig.3.3. three-way two-position valve 22
Fig.3.4. picture of a solenoid valve 24
Fig.3.5. picture of a plc 24
Fig.3.6. three main modules of the PLC 25
Fig.3.7. plc cycles 27
Fig.3.8. Program flow chart 29
Fig.3.9. E-201C pH ELECTRODE 30
Fig.3.10. pH electrode part 31
Fig.3.11. pH sensor module kit pinout 32
Fig.3.12. comparison between the dc output voltage and the pH value 33
Fig.4.1 plc program code 36
Fig.4.2 Do-More simulator 37
Fig.4.3 PLC Simulator configured parameters 38
Fig.4.4 Simulation 1 39
Fig.4.5 SIMULATION 2 40
Fig.4.6 Simulation 2 41
Fig.4.7 Data received from the pH prob 42
Fig.4.8 Simulation 3 43
Fig.4.9 Stop button 44
Fig.4.10 Do-More software main window with a program file open 45
Fig.4.11 Do-More start window 47

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LIST OF TABLES
TABLE 1.1 UNIVERSITY OF ZAMBIA LABS 2
TABLE 3.1 Comparison between the dc output voltage and the pH value 33

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CHAPTER 1.
1.1.0 INTRODUCTION
Many industrial wastes contain acidic or alkaline materials that require special
treatment prior to discharge to receiving waters or prior to chemical or biological
treatment [6].
Neutralization is the process of adjusting the pH of water through the addition of an
acid or a base, depending on the target pH and process requirements. Most part of
the effluents can be neutralized at a pH of 6 to 9 prior to discharge [6].
In this reaction, the acidity of an acid is neutralized by an alkali. At the same time,
the alkalinity of the alkali is neutralized by the acid. Salt and water are the only
products of Neutralization. In chemical industrial treatment, neutralization of excess
alkalinity or acidity is often required. One of the critical items in neutralizing the
water is to determine the nature of the substances that cause acidity and alkalinity.
This is generally achieved in laboratory-scale experiments by preparing titration
curves showing the quantity of alkaline or acidic materials necessary to adjust the
pH of the target wastewater. There are three critical components of any pH control
system according to [6], that is: mixing intensity or turnover time in the reactor,
response time of the control system, and the ability of the chemical metering system
to match process requirements. If anyone of these components is not properly
designed, significant problems in system performance can be anticipated.
1.1.1 THE REACTION
An acid and a base react and give out salt and water. Hydrochloric acid contains
hydrogen ions and chloride ions in aqueous solution. Sodium hydroxide contains
sodium ions and hydroxide ions in aqueous solution. When these two solutions
combine, a neutralization reaction takes place. In this reaction hydrogen ions from

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the acid and the hydroxide ions from the base combine to form water molecules. The
sodium and chloride ions are unaffected and remain to form a neutral sodium
chloride solution. Neutralization can be sum up by simple ionic equation:
H+
(aq) + OH-
(aq) = H2O. During the neutralization, the actual reaction that occurred
is between one hydrogen ion H+ from the acid and one hydroxide ion, OH- from the
alkali to form one molecule of water, H2O. ACID + BASE = SALT + WATER
1.1.2 NEUTRALISATION TANK
Neutralization tank is used to neutralize chemicals effluent before discharging into
the environment. There are so many different neutralization tanks on the market with
different designs but all work based on the same principle of neutralization.
An acid neutralizing tank is designed to normalize the pH level of wastewater
containing high levels of acid before being discharged into the sewer. An acid
neutralizing tank is fitted with three internal baffles and is filled with acid-
neutralizing marble chips to 60% of the water capacity. The three baffles force the
liquid and acidic waste flowing through the tank to filter past the marble chips. This
has the effect of neutralizing the acid thus allowing pH balanced water to be safely
discharged to the sewer.
The neutralization tank to be called a smart tank it must be automated, meaning less
human interaction with the tank. It must be able to do everything automatically in
the background

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NEUTRALIZATION TANKS AT THE UNIVERSITY OF ZAMBIA
Table.1: University of Zambia
The above table shows the departments at the University of Zambia with
neutralization.
1.2.0 APPLICATION OF pH LEVELS
It is important to determine the pH levels, there are so many reasons to why and
some of them are listed below.
1.2.1 AGRICULTURE
In [9] “pH measurement can be applied in agriculture. The pH of soils is important
since plants grow best within a rather narrow pH range. The optimum pH varies with
each type of plant. In hydroponics, pH control is even more important than in the
soil since too high or too low pH can cause precipitation of some of the chemicals.
Helpful soil bacteria grow best in slightly acid soil. Plant nutrients from insoluble
compounds if soil pH is too high. Toxic amounts of some metals become available
if pH is too low.
DEPARTMENT FINDINGS
Chemistry department They don’t have the neutralization tank
Biology department They don’t have the neutralization
School of veterinary They have the neutralization tank but It
stopped working in 1996.

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1.2.2 BREWING
In Brewing, pH is important for proper aging and for all stages of the brewing
process. A decrease in pH decreases the solubility of the bitter parts of hops and
permits the use of stronger hops without an increase in harshness. The beer should
be at a pH of 3.9 to 4.1 when bottled, to ensure stability while on the shelf.
1.2.3 CORROSION
In Corrosion Prevention, the corrosion of iron occurs below pH 4.3 but a semi-
protective layer is formed above 4.3. Acid soils may be below this level. A more
resistant coating is formed above pH 10.5. The thickness of oxide coatings can be
estimated by emf measurements. If the emf is near that of the oxide the coating is
complete and non-porous but if the emf is near that of the base metal, then the coating
has little protective value.
1.2.4 DAIRY INDUSTRY
In the dairy industry, since milk curdles at a pH of 4.7 it must not be allowed to drop
to this value. The aging of cheese can be followed by both emf and pH
measurements. For example, a pH of 4.9 is about right for cheddar cheese. Ice cream
can be spoiled by the addition of fruits or juices with too low a Ph, the pH of cooling
brines must be controlled to prevent corrosion of the pipes.
Example: Cheese Production pH measurements are required for soft, fresh cheese
and hard, mature cheese. Cheese contains a large amount of protein and fat so the
choice of the electrode is important. Often puncture electrodes are used.
1.2.5 DYEING
In Dyeing Processes such as bleaching and dyeing with different types of dye must
be made with a definite pH in order to obtain good results and still not damage the
fabrics. Wool, for example, 16must be neutralized to a definite pH for effective

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dyeing, and in addition, the pH will vary depending upon the nature of the dye itself.
The acid content of the dye also has to be determined which is normally done by
means of titration using a pH meter to determine the
endpoint.
1.2.6 ELECTRICAL EQUIPMENTS
Electrical Equipment, for example, a boiler, the pH of feed waters should be
controlled in order to prevent pipe and boiler corrosion. In most cases, minimum
corrosion occurs between a pH of 7.4 and 8.0. Feedwater can be monitored in order
to detect certain types of contamination. The soda-lime softening process requires a
pH of 9.4 for the removal of calcium and 10.6 for the removal of magnesium.
1.2.7 FERMENTATION
Fermentation reactions, each fermentation process requires a specific pH for the best
results. A change in pH with some bacteria even changes the product. The pH during
a fermentation process changes by itself and must be adjusted periodically. This
maintains optimum conditions and prevents the manufacture of unwanted or even
harmful by-products.
Fertilizer production, the pH of acid type fertilizers is controlled in order to prevent
waste of acid and to ensure a more uniform product.
1.2.8 FLOUR MILLING
Flour Milling, the quality of flour can be determined by making pH measurements,
with the better flours having a lower pH. The overall range is from 5.9 to 6.5. The
buffering qualities of flours are determined by noting the decrease in pH with the
addition of a measured amount of acid.

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1.2.9 GELATIN AND GLUE MANUFACTURING
Gelatin and Glue Manufacturing, the properties of gelatin and glue vary considerably
with the pH during manufacture. pH needs to be controlled accurately to ensure a
consistent product. Colorimetric methods require special sample treatment and are
less accurate.
Iron and Steel pH measurements determine the effectiveness of pickling baths and
neutralization of waste pickle baths. Sand used in sand casting can be improved by
pH control. Proper pH makes the sand hold its shape better.
1.2.10 JAM AND JELLY MANUFACTURING
Jam and Jelly Manufacturing, Jams and jellies have narrow ranges for proper gelling.
A pH of 3.3 is best for jelly. At 3.1 it becomes stiff and at 3.5 quite tender. No gelling
occurs at all above 3.5. Control is effected by using tartaric or citric acid.
Laundries, the efficiency of soaps and detergents can be improved by proper pH
control. Undyed cotton can stand a maximum pH of 11, wool about a pH of 10,
colored cloths 9.6 and silks 9.2. In general, the higher the pH the more efficient the
washing process, but the pH should not exceed the maximum value for the material
being cleaned. Proper pH of starch solutions helps prevent sticking during pressing.
Leather, Close pH control of leather processing is required to obtain maximum
efficiency without damaging the leather. The pH of tanning and dyeing baths actually
determine the texture and color of the finished product. The dehairing process is
normally done at a pH of 12.3, but this must be completely neutralized to assure
good keeping qualities of the leather. Minimum swelling of the collagen is obtained
at pH 4.7.

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Meat and Fish Processing, the pH measurement of meat and fish gives a good
indication of the keeping qualities and freshness of the product. This is a typical
application for a puncture electrode.
1.2.11 METAL FINISHING
Metal Finishing, the effectiveness of the pickling and cleansing baths are determined
by pH measurements. The pH of plating baths determines the quality and speed of
the plating process. Some alloys can be plated if very strict pH control is maintained.
The plating thickness can be found during destructive testing by noting the change
in millivolt readings when the penetration of a coating has been accomplished.
1.2.12 NEUTRALISATION
Neutralizing acids or bases are best controlled electrometrically with a pH meter
which indicates the neutral point more precisely than any other method. The pH
meter is especially useful in colored solutions where a color indicator is of no use.
Printing, the pH of paper and inks must be controlled to assure proper penetration
and drying of the ink. Too high a pH causes gumminess and too low a pH slows up
the drying process.
Pharmaceuticals, Antibiotics produced from molds are grown at a precise pH.
Incorrect pH can possibly produce a poison rather than a medicine. Many
pharmaceuticals must be prepared using very close pH control.
1.2.13 SEWAGE
The pH of sewage is controlled to assure efficient coagulation of sludge. A pH of
either 3.4 or 7.4 may be used for good results. Also, the pH of the effluent water
must be controlled to prevent contamination. The best digestion range is from 6.8 to
7.6. The pH of filtration depends upon the chemicals used; for example, pH 3.4 for
ferric chloride and 4.4 for alum.

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1.2.14 SWIMMING POOL
Swimming Pools, pH levels in swimming pools should be maintained near the
neutral range or slightly alkaline to prevent skin irritations. High pH accelerates the
deposition of solid salts in heater lines and filters. Low pH causes corrosion of iron
pipes etc.
Tropical Fish Breeding, expensive tropical fish thrive within definite pH ranges.
Each species has its own best pH environment, which is even more critical during
breeding. The Neon Tetra Fish, for example, prefers water as close to pH 7.0 as
possible, while an Angel Fish requires pH 6.8. The general range for freshwater fish
is pH 6.0 to 8.0. Saltwater aquariums should be kept at 8.3. If the pH of the saltwater
gets as low as 7.0 the fish become sickly.
1.2.15 WATER
Water, the pH of water sources such as rivers, lakes, and oceans is measured to study
the natural conditions of wildlife. These tests are made by oceanographic institutes,
fish and wildlife services, and water authorities. pH measurements also assist in
determining the extent of pollution in domestic and industrial supplies. In measuring
the pH in water, there are two extreme situations. One is the pH measurement in pure
water (boiler feed water), and the other is the pH measurement in wastewater
(sewage purification plants). In the first case, the medium is very low ions, which
leads to poor conductivity. In the second case, the medium is heavily polluted, which
leads to clogging of the junction. Example: Boiler feed water Power stations use
boiler feed water to create steam. The goal is to have as pure water as possible, which
fully evaporates without leaving any residue. Lime deposits must especially be
avoided. In order to keep the use of boiler feed water within reasonable costs, the
condensed steam is pumped back in. Thus, boiler feed water is very pure distilled
water with a conductivity of sometimes less than 1 µS/cm.”

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1.4.0 OBJECTIVES
To design and implement the neutralization tank for water waste from research labs.
To carry out the simulation of the neutralization tank and implement the design.
To design the control system for the neutralization tank using PLC (programmable
logical control).

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1.5.0 PROBLEM STATEMENT
Currently, Zambia is facing a lot of challenges when it comes to pollution, that is,
land pollution due to chemicals from chemical labs, manufacturing industries, and
mines. This is due to the lack of treatment of the effluent from the aforementioned
chemical producing entities. Some have the chemical treatment plants but don’t have
the capacity, due to the cost of procuring the system. I believe the design I have come
up with will reduce the cost and will be easy to maintain. For example, what had
happened recently where “The Ministry of Mines and Mineral Development
threatened to penalize Mopani Copper Mines over alleged failure to control the
discharge of waste with traces of acid and uranium being emitted in undesignated
areas” [4].

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CHAPTER 2
2.1.0 LITERATURE REVIEW
The goal of this literature review is to compare the already existing neutralization
tanks, there design and how they were implemented and factors considered when
coming up with each design.
Neutralization tanks made by the Viking plastics are one of the companies that makes
neutralization tanks, it has a simple design mainly mechanical where the water from
the lab enters the tank filled with marble chips which neutralize the waste, then
discharged from the outlet [1]. Copying from this design solenoid valves will be
added to control the flow of waste from the neutralization tank into the reservoir
tank, where it will be allowed to stay for some time to complete the neutralization
so that it doesn't go to the environment untreated properly. The pH sensors will be
installed inside the tank.
A review was done on Orion polypropylene and polyethylene neutralization tanks
which are designed to receive, dilute and neutralize corrosive and harmful chemical
wastes before allowing such materials to be discharged into the public sewers or the
environment. The Orion tank makes different sizes of the tanks and tries to achieve
lightweight, Minimum Maintenance, Maximum Versatility [2]. Orion, also, provides
custom made which Is another important aspect in neutralization tanks
manufacturing to meet the customer’s demand. The cost varies according to
customer specifications.
2.2.1 AUTOMATION CONCEPT.
The control system of the tank comprises of the following components required are
as follows: Water Pump, Filter membrane, pH meter, Level Sensors, Control Valves,
PLC.

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Water pumps boosts the water flow from the neutralization tank to the reservoir tank.
Filter membrane filters out the oils or fats and other some large particles which will
slip through into the reservoir tank. PH meter is an indicator, which will be
monitoring the PH levels of the effluent before its discharged to the environment.
Level sensors will be monitoring the levels of the affluent in the reservoir tanks and
the neutralization tank. Control valves will be controlling the flow of the effluent
from one point to another, i.e. from the laboratory to the neutralization tank to the
reservoir and finally to the environment.
LMI pumps use an automation system to control the neutralization tank [3]. It has
the pH sensors which is housed the pH correction system which treats the acidic
effluent for 24hr period. This system has the water level sensors which monitor the
levels of the effluent the correction system. The flow of effluent is controlled by the
solenoid valves which are energized and de0-energenized for them to close and open.
PLC programming language is one of the best visual programming languages and
simple to learn. It’s usually called ladder logic or ladder diagram (LD) and it’s very
easy to learn.
The beauty about ladder logic is that it looks very similar to electrical relay circuits.
Which makes it very easy to learn. And there are so many sources or websites which
offers free plc programming tutorials for free. Bello is an example of a ladder
program [5].

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Fig.2.1: Example of a ladder program
2.2.2 PROGRAMABLE LOGICAL CONTROLLER
In [7] a “Programmable Logic Controller (PLC), also referred to as programmable
controller, is the name given to a type of computer commonly used in commercial
and industrial control applications”. PLCs monitor inputs and other variable values
and make decisions based on a stored program, and control outputs to automate a
process or machine. For plcs proper functionality it is made of different elements
such as input modules or points, a Central Processing Unit (CPU), output modules
or points, and a programming device, and the type of input modules or points used
by a PLC depends on the types of input devices used, some input modules respond
to digital inputs, also called discrete inputs, which are either on or off. Other modules
respond to analog signals. The advantages of PLCs are that its capable of performing
the same tasks as hard-wired control, as well as the more complex applications, they
are also smaller than hard-wire solutions, easier and faster to make changes, they
have integrated diagnostics and override functions, diagnostics are centrally
available, applications can be immediately documented and applications can be
duplicated faster and less expensively. In [8] PLC (The programmable logic

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controller) is defined as a digital electronic device that uses a programmable memory
to store instructions and to implement functions such as logic, sequencing, timing,
counting and arithmetic words to control machines and processes. It controls the
input parameters like pH sensor and Level sensor and output parameters like the
pump, solenoid valves, dc motor, and display. For example, The MicroLogix 1500
(Allen Bradley) Programmable Controller contains a power supply, input circuits,
output circuits, and a processor. This type of controller is available in 24 I/O and 28
I/O configurations. For an efficient and automatic control system, the control system
is implemented using the plc. it controls the input and out parameters like pH
sensors, solenoid valves, motor, booster pumps, etc.
2.2.3 pH SENSORS
In [8] pH sensor, senses the PH level of the wastewater and is controlled by PLC.
there are various types of pH sensors. The selection of a pH sensor is based on the
application and cost. A glass electrode is a type of ion-selective electrode made of a
doped glass membrane that is sensitive to a specific ion. It is an important part of the
instrumentation for chemical analysis and physio-chemical studies. In modern
practice, widely used membranous ion-selective electrodes (ISE, including glasses)
are part of a galvanic cell. The electric potential of the electrode system in solution
is sensitive to changes in the content of the certain types of ions, which is reflected
in the dependence of the electromotive force (EMF) of galvanic element
concentrations of these ions.
A typical modern pH probe is a combination electrode, which combines both the
glass and reference electrodes into one body. The combination electrode consists of
the following parts.
A sensing part of the electrode, a bulb made from a specific glass. An Internal
electrode, usually silver chloride electrode or calomel electrode. An Internal

24. P a g e 15 |
solution, usually a pH=7 buffered solution of 0.1 mol/L KCl for pH electrodes or 0.1
mol/L MeCl for pMe electrodes and when using the silver chloride electrode, a small
amount of AgCl can precipitate inside the glass electrode. The reference electrode,
usually the same type as an internal electrode. The reference internal solution,
usually 0.1 mol/L KCl and the junction with studied solution, usually made from
ceramics or capillary with asbestos or quartz fiber, Body of the electrode, made from
non-conductive glass or plastics. The bottom of a pH electrode balloons out into a
round thin glass bulb. The pH electrode is best thought of as a tube within a tube.
The innermost tube (the inner tube) contains an unchanging 1×10−7mol/L HCl
solution. Also inside the inner tube is the cathode terminus of the reference probe.
The anodic terminus wraps itself around the outside of the inner tube and ends with
the same sort of reference probe as was on the inside of the inner tube. It is filled
with a reference solution of 0.1 mol/L KCl and has contact with the solution on the
outside of the pH probe by way of a porous plug that serves as a salt bridge. [8]
2.2.4 PH MEASUREMENT
In [10] pH measurement is the A measure of acidity or alkalinity of water-soluble
substances (pH stands for 'potential of Hydrogen') with the use of pH sensors
discussed above. ApH value is a number from 0 to 14, with 7 as the middle or neutral
point. All the values below 7 indicate acidity which increases as the number
decreases, 1 being the most acidic. Values above 7 indicate alkalinity which
increases as the number increases, 14 being the most alkaline. This scale, however,
is not a linear scale like a centimeter or inch scale. It is a logarithmic scale in which
two adjacent values increase or decrease by a factor of 10. For example, a pH of 3 is
ten times more acidic than a pH of 4, and 100 times more acidic than a pH of 5.
Similarly, a pH of 9 is 10 times more alkaline than a pH of 8, and 100 more alkaline

25. P a g e 16 |
than a pH of 7. This method was invented in 1909 by the Danish biochemist S. P.
Sørensen (1869-1939).
In [11]. In chemistry, pH is defined as the negative logarithm of the hydrogen-ion
activity. More simply, it is a measure of the relative amount of free hydrogen (H+)
and hydroxyl ions (OH-). That is, it tells the degree to which something, such as soil,
water, or any solution, is basic or acidic. pH is reported in logarithmic units, like the
Richter scale, which represents the strength of earthquakes. Each number represents
a tenfold change in the acidity or alkalinity of a substance. The range goes from 0 to
14, and around 7 is considered neutral. For example, water with a pH of 5 is ten
times more acidic than water with a pH of 6. Additionally, a pH of less than 7
indicates acidity, whereas a pH of greater than 7 indicates alkalinity or a base.
In [9] The qualitative determination of the pH value of foodstuffs is probably the
oldest analysis method in the world. All foodstuffs are tested with the taste organs.
Thereby some are noticed to be acidic and some to be alkaline. With modern pH
electrodes, these taste sensations can be measured in exact figures. Whether
something is perceived as acidic or alkaline depends on the hydrogen ion (H+
concentration in the solution. The pH value is defined, by the Sorenson Equation, as
the negative logarithm of the H+ concentration in a given solution. In other words,
at a high concentration, e.g. 1 mol/L = 100, pH = 0 (ACIDIC) at a low concentration,
e.g. 10-14 mol/L, pH = 14 (ALKALINE)
Hence, different substances are objectively compared with each other, where pH 0
is extremely acidic, pH 14 extremely alkaline, and pH 7 neutral. In the last few years,
the measuring of pH has gained in importance. In the control and regulation of
chemical and biological processes, it has become indispensable to monitor the pH
values. Successful pH measurement can only be achieved by choosing the correct
system to meet the demands of the sample under examination. As well as the correct
apparatus, a supply of suitable reagents is vital

26. P a g e 17 |
2.2.5 SOLENOID VALVE
In [8] a Solenoid Valve is basically an electrical valve that controls the flow of media
either open/closed or diverting by means of an electromagnet or solenoid. The
principles are based around a thin copper wire wound around a bobbin or core (The
solenoid) in such a way that when electrical energy is applied a sufficient magnetic
field is generated to provide a lifting force to a ferromagnetic stainless steel armature
within the solenoid valve armature assembly which in turn will directly or indirectly
change the position of the valve. It is acting as an output parameter for PLC. A
solenoid valve is an electromechanically operated valve. The valve is controlled by
an electric current through a solenoid: in the case of a two-port valve the flow is
switched on or off; in the case of a three-port valve, the outflow is switched between
the two outlet ports. Multiple solenoid valves can be placed together on a manifold.
Solenoid valves are the most frequently used control elements in fluidics. Their tasks
are to shut off, release, dose, distribute or mix fluids. They are found in many
application areas. Solenoids offer fast and safe switching, high reliability, long
service life, good medium compatibility of the materials used, low control power
and compact design. Besides the plunger-type actuator which is used most
frequently, pivoted-armature actuators and rocker actuators are also used
2.2.6 DC MOTOR
In [8] a DC Motor: A dc motor is controlled by PLC. It operates the stirrer. A DC
motor is any of a class of electrical machines that converts direct current electrical
power into mechanical power. The most common types rely on the forces produced
by magnetic fields. Nearly all types of DC motors have some internal mechanism,
either electromechanical or electronic; to periodically change the direction of current
flow in part of the motor. Most types produce rotary motion; a linear motor directly
produces force and motion in a straight line. DC motors were the first type widely

27. P a g e 18 |
used, since they could be powered from existing direct-current lighting power
distribution systems. A DC motor's speed can be controlled over a wide range, using
either a variable supply voltage or by changing the strength of current in its field
windings. Small DC motors are used in tools, toys, and appliances. The universal
motor can operate on direct current but is a lightweight motor used for portable
power tools and appliances. Larger DC motors are used in propulsion of electric
vehicles, elevator and hoists, or in drives for steel rolling mills. The advent of power
electronics has made replacement of DC motors with AC motors possible in many
applications.
2.2.7 LCD DISPLAY
IN [8] LCD Display: It used to display parameters like pH value, level of liquid and
project name. LCD stands for Liquid Crystal Display. LCD is finding wide spread
use replacing LEDs (seven segment LEDs or other multi segment LEDs) because of
the declining prices of LCDs, the ability to display numbers, characters and graphics.
This is in contrast to LEDs, which are limited to numbers and a few characters.
Incorporation of a refreshing controller into the LCD, thereby relieving the CPU of
the task of refreshing the LCD. In contrast, the LED must be refreshed by the CPU
to keep displaying the data. Ease of programming for characters and graphics. It
displays all the alphabets, Greek letters, punctuation marks, mathematical symbols
etc. In addition, it is possible to display symbols that user makes up on its own.

28. P a g e 19 |
CHAPTER 3
3.1.0.0 METHODOLOGY
3.1.1. DESIGN
To achieve the objective of this project simulation has to be done on LabVIEW, do-
more software and other supporting software like ESS (electromechanical system
simulator.). Ladder programming for plc and plc simulators like Lsis XG5000 and
do-more simulator.
Below is the overview of the neutralization tank and how the input and output of the
PLC will be connected to the tank.
FIG.3.1: FLOW CHART

29. P a g e 20 |
The level sensor in the receiving tank will be activated once the maximum level is
reached, the signal will be sent to the plc and this will switch on the pump, and valve
S1 and the effluent will be pumped into the other chamber, the neutralization tank,
where the neutralization will take place, the level sensor in the neutralization is
activated once the effluent reaches the maximum and it sends the signal to the PLC
to stop the pump and closes the valve by reseting level sensor S1 and it also activates
the stirrer. In the neutralization tank, the pH sensor 1 will measure the pH level of
the affluent and send the signal to the PLC. The PLC will determine which tank of
neutralizer to open and neutralize the effluent by following the calibration on the pH
sensor. After the effluent has been neutralized to the allowable pH value the valve
S2 will be opened to release the neutralized effluent to a reserve tank where it will
be stored and later used to either water flowers or in the toilet. Between the
neutralization tank and the storage the affluent will pass through a filter to filter out
the fats and other large particles that maybe present.
3.1.2 SYSTEM COMPONENT DESCRIPTION
For a neutralization tank system design, the main components used are as follows:
Solenoid valve, pump, PLC, filter membrane, pH sensor, level sensors, and DC
motor.

30. P a g e 21 |
3.1.2.1 SOLENOID VALVES.
Solenoid valves are electrically activated valves or electromechanically operated
valves, which are used to control the flow and the direction of air or liquid in fluid
power systems. Used in both pneumatic and hydraulic fluid power functions. [13]
Fig.3.2. Solenoid schematic circuit
Solenoid valves differ in the characteristics of the electric current they use, the
strength of the magnetic field they generate, the mechanism they use to regulate
the fluid and the type and characteristics of fluid they control. The spool of the
valve connects to a ferrous metal plunger which has the spring. The plunger slides
within a core tube of non-ferrous metal, which is surrounded by a coil of electrical
windings. The coil exists with any range of voltage from 12-48 Vdc to 110-220
Vac, and the selection of the component depends on the aplication. When power is
passed through the coil, a magnetic field is induced, which pushes or pulls the
plunger hence shifting the valve. The most basic solenoid valves are two-way, two-
position poppet valves, which simply open and close, modifying their flow path
when their coil is energized. They are available as “normally-open” and “normally-
closed” solenoids, which means normally-flowing and normally-blocked,
respectively. Normally-open in fluid power contradicts normally-open in

31. P a g e 22 |
electronics, which stands for the switch or contact open and not flowing electrons.
Three-way, two-position poppet valves are also common, diverting flow from one
channel to another. Two 3/2 valves in parallel can be used to control a cylinder
bidirectionally. Although construction varies depending on the use, this type of
valve can be used for either pneumatics or hydraulics but is more common to
pneumatic systems. Below is the picture of a three-way two-position solenoid
valve.[13][14]
Fig.3.3. three-way two-position valve
Spool solenoid valves consist of a machined spool which slides within a machined
valve body. One or both ends of the spool are acted upon by a plunger, and when
activated by either coil, pushes the spool one way or the other, allowing three
positional envelopes. The 4/3 hydraulic solenoid valve is one of the most popular,
allowing for bidirectional control of a cylinder or motor from a single valve body.
The “ways” of a solenoid valve refer to how many ports it contains, and the
“positions” of a solenoid valve refer to how many discrete states in which it
operates. A three-position valve employs a spring-centered neutral state along with
two actuated positions.[13]

32. P a g e 23 |
For bidirectional motor or cylinder control, pneumatic valves are machined with
five ports and are referred to as 5/3 valves. The “ways” of a pneumatic valve also
include its exhaust ports, to which there are usually two. Sometimes these same
valves are described as 4-way, 3-position valves, even though close inspection
reveals two exhaust ports bisecting the pressure port.[13][14]
Solenoid valves for either hydraulic or pneumatic applications are available as
manifold-mounted modular units, such as the pneumatic or hydraulic ISO valves.
These valves contain standard mounting and porting patterns, permitting valves
from any manufacturer to be installed upon the same manifold. Most often, these
valves are also quite economical, and readily available. The electrical coils of a
solenoid valve are optioned with either DIN connectors, lead wires, Deutsch
connectors, central connection or any other popular form of electrical connection
used in fluid power and automation. Most solenoid valve coils are field
replaceable, making repair and maintenance easy for technicians. Coils also have a
wide range of applications and purposes. Some are intended for the industrial
environment, where atmospheric conditions are consistent. Mobile environments
are much more demanding and command coils to handle both extreme temperature
ranges and exposure to road film and salt, for example.[13][14]
Fig.3.4. picture of a solenoid valve (with valve open and closed).

33. P a g e 24 |
3.1.2.2 PROGRAMMABLE LOGIC CONTROLLER
Programmable Logic Controller (PLC) is a microprocessor-based system that uses
programmable memory to store instructions and implement functions such as logic,
sequencing, timing, counting, and arithmetic in order to control machines and
processes. PLCs varies in a wide range of sizes, nonetheless, all contain six basic
components, which are: processor or the central processing unit (CPU), rack, input
assembly, output assembly, power supply, a programming unit, PC software for
programming and loading the program into the PLC [12].
Fig.3.5. picture of a plc
It can be also defined as a specialized computer used to control machine processes
by using programmable memory to store instructions and specific function that
includes on and off control, the timer, the counter, the sequencer, arithematic and
also handling data.
PLC are used for continuously monitoring the input values from sensors and
produces the outputs for the operation of actuators based on the program. Every PLC

34. P a g e 25 |
system comprises these three modules: the CPU module, the Power supply module
and one or more I/O modules.[15]
Fig.3.6. three main modules of the plc
CPU Module: A CPU module consists of the central processor and its memory. The
processor is responsible for performing all the necessary computations and
processing of data by accepting the inputs and producing the appropriate
outputs.[15]
Power Supply Module: This module supplies the required power to the whole
system by converting the available AC power to DC power required for the CPU and
I/O modules. The 5V DC output drives the computer circuitry.[15]
I/O Modules: The input and out modules of the programmable logic controller are
used to connect the sensors and actuators to the system to sense the various
parameters such as temperature, pressure, and flow, etc. These I/O modules are of
two types: digital or analog.[15]
Communication Interface Modules: These are intelligent I/O modules which
transfer the information between a CPU and a communication network. These

35. P a g e 26 |
communication modules are used for communicating with other PLCs and
computers, which are placed at a remote place or far-off locate.[15]
The program in the CPU of the programmable logic controller consists of operating
system and user programs. The purpose of the operating system with CPU is to deal
with the tasks and operations of the PLC such as starting and stopping operations,
storage area and communication management, etc. A user program is used by the
user for finishing and controlling the tasks in automation. The programmable logic
controller (plc) has some advantages over the control computer which can also
perform the tasks performed by the plc, because the plc is flexible, has a faster
response rate, it is simple in design, has no moving parts and its easy to repair. it
handles more complicated systems and its also less expensive.[15]
When the plc is initialized, it scans the ladder program rung by rung and executing
the instruction found in each rung. It typically goes in cycles until the necessary
condition is met before the process is stopped.
A typical PLC scans cycle includes the following steps:
• The operating system starts cycling and monitoring of time.
• The CPU starts reading the data from the input module and checks the status
of all the inputs.
• The CPU starts executing the user or application program written in relay-
ladder logic or any other PLC-programming language.
• Next, the CPU performs all the internal diagnosis and communication tasks.
• According to the program results, it writes the data into the output module so
that all outputs are updated.
• This process continues as long as the PLC is in run mode

36. P a g e 27 |
Fig.3.7. PLC cycles
INDUSTRIALAPPLICATION OF PLCS
The PLC can be used in many manufacturing industries like glass manufacturing,
cement industry, washing machines, traffic lights and many more.
3.1.2.3 FILTER MEMBRANE
This is a filter that sieves out large particles that pass through the tank, for
example, the fats.

37. P a g e 28 |
3.1.2.4 PH SENSORS
A pH meter/sensor is an instrument used to measure acidity or alkalinity of a
solution, also known as pH. There different types of ph sensors made by different
manufacturers. Some of the most common ph sensors or rods. In this project GF
Signet 8750 was used to implement ph monitoring.
3.1.2.5 LEVEL SENSORS
level sensors are used to identify the point at which a liquid falls below a minimum
or rises above a maximum level. Some types use a magnetic float, which rises and
falls with the liquid in the container. Once the liquid reaches a certain level, a reed
magnetic switch is activated.
3.1.2.6 DC MOTOR
A DC motor is an electrical machine that converts electrical energy into
mechanical energy. The basic working principle of a DC motor is, whenever a
current-carrying conductor is placed in a magnetic field, it experiences a
mechanical force.
3.1.3.0 Control System Implementation
The implementation was divided in parts and these are:
1. First is the schematic diagram and the flow chart
2. Secondly the pH sensor implementation stage
3. And then valve operation
4. finally the ladder programming, simulation and the results.

38. P a g e 29 |
Fig.3.8. Program flow chart

39. P a g e 30 |
3.1.3.1 Flow Chart
The above flow chart shows how the ladder program flows from the time
initialization or execution to the last.
Firstly the level sensor LS1 in the receiceing chamber goes high when its full, inturn,
this activates the the solenoid valve 1 and the pump, pump1. After all the affluent
has been pumped out of the receivining tank, level sensor, LS1, will be turned off
when the second level sensor in the neutralization chambers goes high or is
energized, hence switching off the pump and closing the valve.
The moment level sensor LS2 is energized the stirrer starts rotating by turning on
the motor of the stirrer at the same time the pH sensor starts reading the acidity of
the affluent. The signal based on the acidity of the affluent, will be sent to the pH
wich will determine how much reagent is needed to neutralize and for how long it
should last. The pH sensor number two will also be monitoring the acidity, the sole
purpose of the second ph sensor is stop the addition of the reagent when the safe
acidity level is reached hence closing all the valves found the at the outlets of the
reagent containers. When the pH is within the accepted range the second level sensor
will open the solenoid valve two (2) and the nuetralised affluent wll be stored in the
storage chamber where it will be used for whatever the user intended purpose.

40. P a g e 31 |
3.1.3.2 SENSOR IMPLEMENTATION
Fig.3.9. E-201C pH ELECTRODE
After thorough reseach and recommendations about pH electrode, a glass electrode
E-201C was selected to be used in this project. The figure 3.9 below shows the pH
electrode. pH electrode E-201C is an electrode type combination sensor where an
internal silver chloride is used by Programmable logic Controller using CCW for pH
maintenance as electrode to detect the amount of hydronium ions and generate
potential or voltage according to the pH reading. Here the tubular structure of glass
is the sensing part, the ph sensitive part. It uses of salt bridge principle for getting
the potential difference, this potential is compared with reference potential by a
solution of KCl of pH=7.[16]

41. P a g e 32 |
Fig.3.10 pH PROBE
The pH sensor module comes with ph sensor or probe and the signal conditioning
board which gives an output which is propotional to the pH value and can be
interfaced directly into the microcontroller.[16]
Internal architecture.
Fig.3.11 pH electrode part

42. P a g e 33 |
Figure 3.10 shows the internal or the architecture of the pH electrode and the parts
that makes up the electrode.
Fig.3.12. pH sensor module kit pin out
The figure above is the pictorial view the set up circuit of the temperature sensor
module included is the port the ph prob is connected and the temperature sensor data
pin which contains the vcc, data, and the ground. Other components are the offset,
the power indicator, the temperature output and other pins.[16]
Table.3.1. Comparison between the dc output voltage and the pH value

43. P a g e 34 |
CHAPTER 4
4.1.0.0 SIMULATION AND RESULTS
Below, in figure 4.1, is the program for the plc which was loaded in the simulator
and the results of performance were noted and analysed.

44. P a g e 35 |

45. P a g e 36 |
Fig.4.1 PLC program code

46. P a g e 37 |
In figure 4.2 is the PLC simulator. It has both digital and analog inputs and outputs.
On the digital side the iputs range from “X0” to “X15” and the output ranges from
“Y0” to “Y15”. The analog inputs ranges from “WX0” TO “WX7” and the outputs
ranges from “WY0” to “WY7”.
Fig.4.2 Do-More simulator

47. P a g e 38 |
Fig.4.3 PLC simulator configured parameters.
In Figure 4.3 above shows the plc configurations such as time and date on the system
clock settings, the operating system version, the PLC type, the serial number, the
scan times, the node and ip configurations etc.

48. P a g e 39 |
After loading the ladder program in the simulator, it was put in run mode by
putting the slider on the left on ‘RUN’ as shown in figure 4.4 below.
Fig.4.4 simulation 1

49. P a g e 40 |
In simulation number 2, figure 4.5, the level sensor number one (LS1) represented
by input “X4” was toggled. The output Y2 and Y4 went high representing the
solenoid valve and the pump respectively.
Fig.4.5 simulation 2

50. P a g e 41 |
After all the affluent has been pumped out the receiving chamber level sensor
number two (LS2) goes high hence resetting level sensor number one (LS1). This
stage is shown in figure 4.6. When level sensor number 2 (LS2) represented by
“X0”, was high the stirrer started rotating, represented by output ‘Y1’ and stayed
high.
Fig.4.6 simulation 3
The next stage is when the pH probe reads the pH levels of the affluent and sends
the data to the plc which determines the reagent to add into the neutralization tank.
This process is shown the figure below.

51. P a g e 42 |
Fig.4.7 data received from the pH prob
In figure 4.7 shows how the signal received from the pH probe is analysed, and the
descission the plc makes is based on the data which is processed here. There are
three conditions, the acidity level, with the highest voltage, the neutral level and
the alkalinity level.

52. P a g e 43 |
Fig.4.8 SIMULATION 3

53. P a g e 44 |
In figure 4.9 when the stop button, represented by ‘X6’, is high all the processes
must stop. In the figure below all the outputs went low because the stop button was
or went high pressed.
Fig.4.9 stop button
The vlaves controls the flow of the affluent from one chamber to another by
receiving or following the commands from the PLC. They do so by opening and
closing due to the magnetization process in the coil.

54. P a g e 45 |
Do-more Designer is the full-featured PLC programming software for the Do-more
series of programmable logic controllers (PLCs). Flexible program management
supports a mix of stage and ladder logic for a best-of-both-worlds approach that
simplifies programming and makes trouble-shooting easier. Do-more Designer
Software is offered as a free download from the Automationdirect.com Web site. It
is a free software for programming and it has an inbult simulator that comes in
handy when the actual PLC isn’t avalaible. It has user friendly interface for ladder
programming and it is easy to learn. The DO MORE software is provided by the
automation direct. The do-more software has a lot of advantages compared to
others, PLC software provides the tools to program and configure the hardware for
your specific needs.[17]
Fig.4.10 Do-More software many window with a program file open

55. P a g e 46 |
The Do-more Designer Programming Software comes with a lot of cool features,
some of them are metioned below [17];
• It's Free and it’s the Same software for all Do-morePLCs and BRX Product
Lines.
• Easy Navigation Software Dashboard With quick links to important tools
and screens.
• Built-in Software Videos Getting started videos, instructional videos,
download utility.
• Built-in Simulator Creates a virtual PLC to test program logic without a PLC
present.
• Local I/O is Automatically Configured The I/O config window shows auto-
discovery of modules in the local base.
• Optimized instruction set Based on customer requests and developed with
flexibility and ease of use.
• Powerful, Intuitive Math Allows mixing of data types and accepts formulas
and variables.
• High-speed I/O and Motion Control: Simplified Dedicated instructions allow
you to choose complexity.
• Communications Are Easy To define, troubleshoot and share data over
serial/Ethernet.
• Data Logging & File Management 1MB internal RAM storage with
microSD support and email capabilities.
• Do-more Designer software is also available on CD for.
• Do-more Designer Software Features.
In figure 4.11 is the window or the start windows showing some features
mentioned above.

56. P a g e 47 |
Fig.4.11 Do-More start window
Do-more PLC Programming Software Instruction Set are optimized for flexibility
and ease-of-use. The Instruction toolbox and Element Picker allow quick selection
and insertion of instructions and elements into the Do-more program. The powerful
spreadsheet style MATH instruction allows mixing of data types and accepts
formulas and variables. It has dedicated High Speed I/O & Motion Control
instructions greatly simplify and improve functionality and communications are easy
to set up, define and troubleshoot. It comes with powerful monitoring and trouble-
shooting tools allow precise tuning of PID loops; monitoring of program elements
and status bits.[17]

57. P a g e 48 |
Do-more Designer program management tools support a mix of stage and ladder
for a best-of-both-worlds approach that simplifies code and makes troubleshooting
easier.
Project Management - all project files are stored on-board the CPU, no more
searching for the most recent copy of the program.
Do-more Designer offers versatile password protection for multiple users and
assigning combinations of privileges from available options.
Do-more! Designer Compatibility and Hardware Requirements. the Do-More
software is compatible with any of these PC operating system which are, all
Microsoft windows versions both 32-bit and 64-bit operating sytem. The hardware
Requirements for do-more software to function properly are HD Space of 305Mb
and Video quality of 1024x768 and the color of 256.
With these requirements makes do-more software more preferable for this project
because it has little or non-campatility issues.

58. P a g e 49 |
CHAPTER 5
5.1.0.0 CONCLUSSION
Manualization of some parts of waste water nuetralization process has some
shortcomings. All manually operated systems needs frequent human interaction with
the system, hence, tend to put burden on persons working with it and such systems
are prone to errors caused by the operator. For example the company has a manually
operated neutralization tank, Everytime the operator has to check the level of affluent
in the receiving tank before the open the valves and pump the affluent into the
neutralization tank, even when its pumped into the neutralization tank the operator
has to mearsure the pH and calculate how much reagent is neede based on the the
measured pH. The effective and efficiency of running manual system is heavily
dependent on individuals experience and therefore management bear the
responsibility to train the personels who handles the equipment continuously. But
still even by doing so the problems don’t end there, for instance if the operator goes
on leave or is sick the work comes to a stand still not until the operator is back and
the production is affected indirectly. Hence automating the equipment the most
utmost option in order to improve on service delivery and production.
The advantages of automating the neutralization are that it reduces the errors
encountered in manually operated systems, for example, spillages due to
overflowing, discharging the affluent that is not fully neutralized due to poor
workmanship or negligence. It also reduces on the cost in the long run, instead of
spending money on training the operator that can be channeled to automating the
neutralization plant hance cutting off cost spent on human labor. This system is
applicable to almost all the system that works with chemicals.

59. P a g e 50 |
5.2.0.0 RECOMMENDATIONS
From this project it can be recommended that:
1. The simulated automatic water waste neutralization tank should be prototyped
and do the test run on the actual PLC and all the components needed.
2. The number of pumps should be increased to at least two, for a large system,
to reduce filling time of the affluent from the receiving chamber to the
neutralization chamber.
3. The PLC programme should be upgraded to include measurements of quantity
of affluent in the tank and to also predetermine the amount of reagent that
should be added upon the measurement of the affluent.
4. The overflow sensor should also be improved
5. And lastly for small plants I would suggest using Arduino interface to be used
for control system and compare the performance between the plc and the
Arduino

60. P a g e 51 |
APPENDICES
PROGRAM
Below is the program code for the PLC.
// Beginning of Code Block $Main
$PRGRM $Main
// Rung $Main#1
// Offset 0
STR X4
ANDN X6
ANDN X0
OUT Y2
SET Y2
// Rung $Main#2
// Offset 5
STR X4
ANDN X6
ANDN X0
OUT Y4
SET Y4
// Rung $Main#3
// Offset 10
STR X0
ANDN X6
OUT Y1

61. P a g e 52 |
SET Y1
RST X4
// Rung $Main#4
// Offset 15
STR X1
CLAMP D0 5 2.71 D1
CLAMP D0 2.535 2.22 D2
CLAMP D0 2.06 0 D3
// Rung $Main#5
// Offset 32
STRN X10
COPY 0x1 "4 0x0 D1 X7 3"
// Rung $Main#6
// Offset 40
STR X7
OUT Y3
// Rung $Main#7
// Offset 42
STR X8
OUT Y5
// Rung $Main#8
// Offset 44

62. P a g e 53 |
STR X9
OUT Y6
// Rung $Main#9
// Offset 46
END
// End of Code Block $Main
$PGMEND $Main
#BEGIN ELEMENT_DOC
"X0","LS2","",""
"X1","pH1","",""
"X4","LS1","",""
"X6","STOP","",""
"Y0","s1","",""
"Y1","STIRRER","",""
"Y2","VALVE1","",""
"Y3","VALVE2","",""
"Y4","PUMP","",""
"Y6","VALVE4","",""
"WX0","VALVE3","",""
"C0","sph1","",""
"C1","sph2","",""
"C2","l2","",""
#END

63. P a g e 54 |
ZABS BACTERIOLOGY

64. P a g e 55 |
PH VALUE OF KNOWN SUBSTANCES

65. P a g e 56 |
REFERENCE
[1] Viking plastics. (2015). “acid neutralization tank”. (online)
https://vikingplastics.com.au/wp-content/uploads/2015/11/Acid-Neutralising-Tank-Cut-away-
view-Valve-not-included.jpg?x44179
[2] Orion fittings. (2019). “TM TANKS”. (online article).
http://www.orionfittings.com/tm_tanks.asp
[3] LMI PUMPS. (2019). “case study: fully automatic pH correction system”. (online article).
http://www.lmipumps.co.uk/case-studies/fully-automatic-ph-correction-system
[4] ZAMBIA REPORTS. (2019). “GOVERNMENT THREATENS SUNCTIONS MOPANI
WASTE DISCHARGE”. (online article). https://zambiareports.com/2019/03/04/govt-threatens-
sanctions-mopani-waste-discharge/
[5] LADDER LOGIC TUTORIAL FOR BEGINNERS. (2017). “plc programming”. (online
article). https://www.plcacademy.com/ladder-logic-tutorial/
[6] Pablo Ures Rodríguez, Alfredo Jácome Burgos, Joaquín Suárez López. (2014). “pH
NEUTRALIZATION (FS-PRE-004)”. FS-PRE-004.(online article). [accessed: 16 may 2019]
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&ved=2ahUKEwjVj5
GC8aDiAhXKAWMBHVSRCUcQFjACegQIBBAC&url=https%3A%2F%2Fwww.wateraction
plan.com%2Fdocuments%2F177327%2F558166%2FpH%2BNeutralization.pdf%2F590e7971-
a8fb-0e4e-97b1-733a781df09f&usg=AOvVaw04zkWJDrNKYolcHzSWf-yM
[7] electrical engineering portal (2017).“BASICS OF PLC s”. EEP. (online article). [accessed: 29
April 2019].
https://electrical-engineering-portal.com/download-center/books-and-guides/siemens-basics-of-
energy/basics-of-plcs

66. P a g e 57 |
[8] Er. Ravinder Kumar, Sahil Jungral, Tavleen Singh, Ankit Gupta, Tanveer Hussain Khan.
(2016). “EFFLUENT TREATMENT PLANT USING PLC”. International Journal of
Engineering Research and General Science Volume 4, Issue 2. (online article). [accessed on 10
June 2019]. www.oaji.org/articles/2016/786-1461987305.pdf
[9] “A GUIDE TO pH MEASUREMENT - the theory and practice of laboratory pH
applications”. Journal. (online article). [accessed on 10 june 2019]
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=18&ved=2ahUKEwj9rb
v8zeHiAhVCnuAKHZFbB_QQFjARegQIBxAC&url=https%3A%2F%2Fwww.mt.com%2Fmt_
ext_files%2FEditorial%2FGeneric%2F1%2FGuides_to_Electrochemical_Analysis_0x000248ff0
0025c9a00093c4a_files%2Fguideph.pdf&usg=AOvVaw2bJW2njYCqnrD8miTQUEb4
[10] “ PH SCALE”. Business dictionary. (online article). [accessed on 11june 2019].
http://www.businessdictionary.com/definition/pH-scale.html
[11] M. J. SINGER, UC Davis; H. A. GEORGE, C. D. CHILDERS, M. L. MERRILL-DAVIES.
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