“HOW TO MAKE SLOW SAND FILTERS LESS LABOUR INTENSIVE AND ALLOW THEM TO BE COVERED”

“HOW TO MAKE SLOW SAND FILTERS LESS LABOUR INTENSIVE AND ALLOW THEM TO BE COVERED”

Abstract

The primary processes in the study play an essential and important role in pointing out the factors associated with a low economy at Kempton waterworks. The main purpose of filtration is mainly to separate inseparable or coarser materials from water. Filtration is mainly undertaken at the final stage of water treatment plant after it passes through another preliminary process. Sand filters are classified on the basics of slow and rapid. Slow sand filter mainly consists of finely separated by fine sand or gravel. Cleaning and maintenance techniques at slow sand filter are a relatively bigger issue faced by owners. Construction of permanent structure effectively plays an essential part in breaking the contact between direct rays of the Sun and raw water. Findings and analysis from the study illustrate the cost specification for each covering material and methods of treatment applicable at Kempton waterworks. It will help the users in understanding the factors which mainly influences the cost of slow sand filters. Overall findings and analysis from the study indicate the importance of covering filters for preventing the growth of algae. The major process in the study plays an active role in determining the amount of cost necessary and to be encountered in water quality treatment. The main factor which largely influences the quality of water includes the frequency of cleaning and improvement operation. The rate of cleaning and development operation depends on the process of cleaning at Kempton waterworks. Different types of cleaning mechanisms are discussed in the study. A permanent structure is one of the most essential and valuable methods to be used and preferred over other measures. Scrapping and chemical treatment process are not suitable in comparison with others. Scrapping process involves a certain amount of unnecessary costs due to wastage and removal of filter media. Apart from that, the manual requirements for cleaning action are demanding and higher as a result permanent structure is preferred.

Acknowledgement

I (Name of the student) would like to express sincere gratitude to my teacher (Name of the teacher) for giving me this excellent opportunity to perform this fantastic project on the topic

“HOW TO MAKE SLOW SAND FILTERS LESS LABOUR INTENSIVE AND ALLOW THEM TO BE COVERED”

I would like to thank my teacher for offering me help and sufficient amount of guidance on different matters related to it. This project has helped me in knowing and understanding different latest things. I am thankful for the real contribution.

I would thank my parents for offering me all sorts of guidance and necessary help for presenting this project in a well-defined manner and in time. I would also like to thank my friends for encouraging and sharing all sorts of ideas which added more value to the project.

Table of contents

Chapter 1.0: Introduction 11

1.1 Introduction 11

1.2 Background 11

1.3 Problem statement 11

1.4 Research rationale 12

1.5 Working principle of slow sand filter 12

1.6 Factors contributing to its labour intensiveness 14

1.7 Research aim 15

1.8 Research objectives 15

1.9 Research question 15

1.10 Research Hypothesis 15

1.11 Significance of the research 15

1.12 Structure of the dissertation 16

1.13 Summary 16

Chapter 2.0: Literature review 16

2.1 Introduction 16

2.2 Conceptual framework 17

2.3 Factors influencing the quality of water 18

2.3.1 Justification of cost 18

2.4 Theories and models 21

2.5 Covering materials 21

2.5.1 Partial or complete coverage 21

2.5.2 Retractable structure 22

2.5.3 Suspended coverage 24

2.5.4 Floating covering material 25

2.6 Factors mainly influencing the cost of slow sand filter 26

2.7 Cleaning mechanisms of the filters and justifications for its usages 26

2.7.1 Robotic cleaning mechanisms of algae and schmutzdecke 26

2.7.2 Scrapping and backwashing 27

2.7.2.1 Scrapping process 27

2.7.2.2 Backwashing process 27

2.7.3 Chemical treatment process 28

2.7.3.1 Copper sulphate 28

2.7.3.2 Ozonation 29

2.7.3.3 Aeration treatment 29

2.8 Treatment methods 30

2.9 Literature gap 31

2.10 Summary 32

Chapter 3.0: Research Methodology 32

3.1 Introduction 32

3.2 Cost of the cover 32

3.3 Robotic method of cleaning of schutzdecke and algae cost 33

3.4 Cost of chemical treatment 34

3.5 Cost of algae aeration 35

3.5.1 Cost of algae aeration 36

3.6 Cost of sonication 36

3.7 Water quality 42

3.8 Chemical tests 42

3.9 Physical test 43

3.10 Bacteriological tests 43

3.11 Timeline 43

3.12Summary 43

Chapter 4: Data findings and analysis 43

4.1 Introduction 43

4.2 Secondary analysis 43

4.2.1 Importance of permanent solution 44

4.2.2 Analysis of cost of all probable solutions 45

4.2.2.1 Cost Analysis – 1 45

4.2.2.2 Cost Analysis – 2 46

4.2.2.3 Cost Analysis – 3 47

4.2.2.4 Cost Analysis – 4 48

4.2.2.5 Cost Analysis – 5 48

4.2.2.6 Cost Analysis – 6 49

4.2.3 Efficiency analysis regarding potential solutions 49

4.2.4 Application of decision matrix to identify the best solution 51

4.2.5 Design of the structure 52

Figure 4.2.5: Sections in filter 52

4.2.6 Cost of the structure 52

4.2.7 Influence of water quality 54

4.3 Summary 54

Chapter 5: Conclusion and recommendation 55

5.1 Conclusion 55

5.2 Linking with objectives 55

5.3 Recommendation 56

5.4 Limitation 57

5.5 Future scope of the study 57

Reference list 59

Appendices 63

Appendix-1 63

List of figures

Figure 1.1: Cross sections of slow sand filter 11

Figure 1.2: Isometric elevation view of slow sand filter 12

Figure 1.3: Slow sand filter 12

Figure 2.5.2: Photo of retractable structure 22

Figure 2.5.3: Image of suspended coverage 23

Figure 2.4: Image of floating coverage 24

Figure 2.7: Backwashing process 27

Figure 2.7: Ozone Treatment 28

Figure 2.7.1: Aeration basin 29

Figure 2.8: Water treatment process 30

Figure 3.5: Algae concentration and types 34

Figure 4.2: Illustration of different filers at water works 43

Figure 4.2.1: Illustration and dimensions of single filter 44

Figure 4.2.3: Cost of covering material per square meter 45

Figure 4.2.4: Annual costs of chemicals in pounds 46

Figure 4.2.5: Cost of particulars for aeration 47

Figure 4.2.6: Cost of particulars materials for sonification 47

Figure 4.2.7: Cost of scrapping 48

Figure 4.2.5: Sections in filter 51

List of tables

Table 2.3: Cost priority 18

Table 2: Table containing survey results on partial or complete coverage 22

Table 3.2 Costs for cover 33

Table 3.3: Robotic cleaning mechanisms 34

Table 3.40: Cost table of different chemicals 34

Table 3.5: Cost of basic requirements of aeration 36

Table 3.6: Apparatus requirements for sonification 37

Table 3.6: Table of cost specifications 38

Figure 3.6: Permanent structure in slow sand filter 38

Table 3.6: Cost specifications of permanent structure 39

Table 3.6: Cost specifications of permanent structure 39

Table 3.6: Cost specifications for backwashing 41

Table 3.6: Cost specifications of scrapping 42

Table 4.2.3: Cost specifications for each task 50

Table 4.2: Decision matrix and efficiency 51

Table 4.2.6: Cost specifications for respective items 53

Chapter 1.0: Introduction

1.1 Introduction

Filtration plays an important role in overall treatment process. The main purpose of filtration is mainly to separate solids from liquids and greases using a filter media. The main purpose of filtration is mainly to separate inseparable or coarser materials from water. Filtration is mainly undertaken at the final stage of water treatment plant after it passes through another preliminary process. Filter may be classified on the basics of slow and rapid sand filter. Slow sand filter mainly consists of finely separated by fine sand or gravel. Huge requirements of labour for cleaning operation increase the cost of maintenance. This study mainly focuses on determining and analysing possible ways for lowering the cost of maintenance. Apart from that, it also focuses on determining suitable covering material.

1.2 Background

The process associated with slow sand filtration mainly consists of semi-centralized or centralized water purification systems to be used before its final water distribution. Seeger et al. ( 2016) mentioned that properly well-designed filtration plays an important role in the effective removal of turbidity. Slow sand filter is quite effective in treatment process. It requires greater surface area than other rapid sand filters. Pfannes et al. (2015) commented that greater surface areas require more cost. It is labour intensive mainly due to its cleaning mechanisms. It requires sufficient amount of attention on a regular basis, basically for identifying the presence of any clog in its cleaning mechanisms and its removal. It requires sufficient amount of labours depending on the perimeter for cleaning. Usually, on suitable conditions, it requires cleaning within 1-2 months intervals. Cleaning mechanisms by manual labours make it labour intensive and increase its maintenance cost.

1.3 Problem statement

The problem statement of the study is mainly to analyse the main factors on increase in the cost of slow sand filters. Frequency of cleaning and increase in the cost of maintenance of slow sand filter makes it labour intensive.

1.4 Research rationale

The cost is one of the most important and fundamental aspects of development and maintenance of slow sand filter. The main issue is mainly concerned with the increase in cost due to maintenance. Increase in cost due to labour involvement and frequent cleaning mechanisms are affecting the main operations.

Constant involvement in the filter concerning its cleaning mechanisms is affecting sufficiently affecting the amount of overall efficiency. Increase in more labour involvement is taking more resources for maintenance operation

Amount of disposition of alga and Schmutzdecke are offering sufficient amount of difficulty periodic cleaning operation and the reaction of chemicals from algae is placing considerable impacts on the water, making it unfit for human consumption (Pizzolatti et al. 2015).

This research plays an essential and important role in pointing out the main factors responsible for algae growth and important factors to be considered for lowering its cost.

1.5 Working principle of slow sand filter

The use of the slow sand filter is of traditional origin and is used mainly in the areas of Europe and UK. As a result of its expensiveness as compared with rapid sand filters, it is mainly preferred. Pfannes et al. (2015) commented that slow sand filter is regarded as direct or straightforward waste water treatments.

Figure 1.1: Cross sections of a slow sand filter

(Source: gov.uk, 2018)

Filters mainly comprise of two main storage functions. Raw water is allowed to enter and is mainly kept at a constant head. Below, filter media is present through which water is coming in is allowed to enter and pass slowly.

Figure 1.2: Isometric elevation view of a slow sand filter

(Source: gov.uk, 2018)

Filter media effectively consists of pores made up sand grains. Presence of larger particles is captured and eliminated. As the water, upon passage through filter media separates presence of other smaller particles. Grace et al. (2016) mentioned that the whole process repeats with the downward movement of water. More and more small particles are removed effectively with every downward movement of water.

Figure 1.3: Slow sand filter

(Source: gov.uk, 2018)

Small sized particles are effectively trapped in between grains of tightly packed. This process is known as screening. Continuing the process of screening, due to the presence of particles in the raw water, a layer of particles gets deposited on the surface bed known as Schmutzdecke, which is collected and separated, later on, allowing the clean water to pass.

1.6 Factors contributing to its labour intensiveness

The basic procedures followed by sand filters are relatively easier and straightforward. However, the main cost involved in the process is due to its frequent maintenance. It requires cleaning procedure due to the growth of algae and development of Schmutzdecke on a regular basis due to clogging. This factor makes the whole process complicated and costly. The factors are mentioned as follows:

The growth of algae: Growth of excessive amounts of cyanobacteria and growth of algae in the filter and basins ensure hazardous effects on the drinking water. As a result of too much deposition and lack of timely removal, the water attains green colour. The green colour is mainly due to the deposition of algae. The main effect associated with this regard is unpleasant to taste of final water (Schijven et al. 2014). Apart from that, the presence of algae may also emit certain chemicals whose consumption may negatively effect the health of the consumers. The growth of algae is directly responsible for sunlight. This growth is mostly greater in the summer season. Thus, the amount of cost necessary for cleaning is sufficiently more in summer than in other seasons.

Presence of Schmutzdecke: The term schutzdecke is mainly defined as sedimentation of suspended particulate matter on the filter. As per figure 1.3, the layer of sedimentation is illustrated. This layer is mainly formed due to constant deposition of sediments with the passage of time. Apart from that lack of periodic cleaning increases its concentration. This layer is highly and heavily biologically active as it mainly consists of the presence of microorganisms such as plankton, bacteria. Pompei et al. (2017) mentioned that continuous disposition of Schmutzdecke blocks the filter beds and its necessary to be scrapped off at regular intervals. Regular removal and scraping of this layer increase its labour intensiveness. During its process of scrapping, the certain portion of the filter is removed as well which requires re-sanding. However, re-sanding makes it more labour intensive. In Comparison with algae growth, cleaning due to re-sanding may be performed within an interval of four to five years depending on the amount of concentration.

1.7 Research aim

The aim of this study is to identify the process of making sand filters that are less intensive by allowing them to cover the main costs of construction. In addition to it, the best possible material necessary for covering is to be determined.

1.8 Research objectives

The main objectives of the research are stated as follows:

To understand the concept and operations of slow sand filters

To understand and analyse several factors responsible for increase in cost for maintenance of slow sand filters

To determine the process or techniques to be undertaken to lower the costs of slow sand filters and increase its efficiency

To determine the best possible covering material for slow sand filter to prevent algae growth

1.9 Research question

The main research question in concern as per the research work is:

“What are the best possible techniques which may be utilized to lower the maintenance cost of slow sand filters and possible covering material to be used”

1.10 Research Hypothesis

H0: There is sufficiently no specification of the necessity of procedure

H1: There is the significance of making slow sand filters in construction procedure

1.11 Significance of the research

As per the viewpoint and opinion of Schijven et al. (2014), structure is necessary and essential to be made in such a way such that long-term costs are relatively minimized. Permanent structure is important and is essential to be constructed for long-term efficiency. Graham and Collins (2014) mentioned that the costs associated with maintenance are the only cost to be invested in periodic intervals after permanent structure. The study is significant in order to point out and analyse the major factors affecting the costs of slow sand filters. It is also significant in determining the best possible covering material to prevent the growth of algae and ensuring maximum efficiency.

1.12 Structure of the dissertation

1.13 Summary

This section plays an efficient and important role in analysing and pointing out the main factors responsible for deposition of algae and schutzdecke. The major factors actively responsible for the increase in maintenance cost are investigated as well. The contributions derived by a slow sand filter and its advantages regarding value being delivered are discussed as well.

Chapter 2.0: the Literature review

2.1 Introduction

This section will mainly look forward towards analysing and pointing out the aspects of a sand filter. It will identify and point out the relation between the amount of cost necessary to be invested and the value delivered. This section will also cover all significant possible solutions directly related to labour intensity and main parameters for cost reduction.

Water quality

The economy of slow sand filters

FACTORS

Physical characteristics

Chemical properties

Bacterial properties

FACTORS

Cleaning frequency

Materials used in the structure

Covering materials

THEORY AND MODEL

Physical properties of water and bacterial properties

THEORY AND MODEL

Structural and maintains properties

Impacts

Improvement in water quality

CHALLENGES

Ensuring overall economy for water quality

2.2 Conceptual framework

2.3 Factors influencing the quality of water

The quality of water largely depends on various factors such as the number of chemicals used in the process. The process associated with slow sand filtration mainly consists of semi-centralised or centralised water purification systems to be used before its final water distribution. Seeger et al. (2016) mentioned that properly well-designed filtration plays an essential role in the effective removal of turbidity. The slow sand filter is quite effective in the treatment process. It requires greater surface area than other rapid sand filters

The quality of water largely depends on the amount of protective material and the influence of direct sunlight. As mentioned by Bai et al. (2015), direct sunlight will promote and favours growth and development of algae, which releases a certain amount of chemicals and odours which strongly impacts on overall water quality. However, on the other hand, Pivokonsky et al. (2016) mentioned that the quality of water is mainly influenced by the frequency of cleaning and the influences of covering materials.

2.3.1 Justification of cost

Parameters

Priority

Permanent structure

Medium

Materials used in construction

Low

Structural design

Medium

Wages of the labour

Medium

Cleaning and maintenance mechanisms

High

Table 2.3: Cost priority

(Source: learner)

As mentioned by Hoyland et al. (2014), the cost associated with water treatment plant depends mostly on different inputs and costs in its treatment process. The overall cost of the structure at Kempton water works depends mainly on various and essential parameters. The most critical and crucial parameter associated to waste water treatment is its maintenance cost. The initial cost in the process may not sufficiently higher depend on its proximity to its area of collection and distribution. Location of Kempton water works within reach of Thames River will reduce the cost of pipes for transporting and electric power for motor operation. However, costs associated with maintenance will strongly impact on its cost in the long run. The choice for selection of materials depends upon different factors regarding economy and its effectiveness. Altenburger et al. (2015) mentioned that the structure is essential and necessary to be formulated for ensuring overall efficiency. In the waterworks of Kempton waterworks, twelve different filters are provided. The mode of structural considerations and the positioning of filters are important as well. The positioning of the structure such as individual or twelve different structures available for each filter is important.

There may be a presence of individual structure for all filters. There may also be a single structure for accommodating all filters. However, on the other hand, Shaw et al. (2014) mentioned that the positioning of the filter and structure impacts a lot on overall cost. The cleaning machinery and its relevant costs also influence its costs.

Figure 2.3: Factors influencing marine and aquatic life

(Source: gov.uk, 2018)

The main factors and disposition responsible for the deterioration of water quality are the presence of algae and deposition of materials such as schmutzdecke in the filter beds. The maximum amount of efficiency in cleaning is essential for assuring maximum amount of water quality. On the other hand, Stein et al. 2017 commented that that presence of microorganisms in the layer of schmutzdecke is also known as flora. Sand filtration highly relies on the flora of about 90% to 99% in effective removal of microorganisms such as bacteria and viruses. The cleaning functions are mainly controlled by a sensor. It determines and measures the head of output of water.

Rise or fall in the pressure head of output of water is captured by a sensor, which alarms for cleaning function (Stein et al. 2017). The amount of water input and corresponding water output which when gets lower than the amount of water input are indications of clogging of the surface of the filter. The different types of cleaning procedures which are essential to be followed are illustrated later.

Figure 2.3: Diagram of filter

(Source: gov.uk, 2018)

2.4 Theories and models

As per the theory of filtration, the water after its passage through different sections may not be total or overall pure prior to sedimentation. It may contain a certain amount of particles which are important and essential to be separated for encouraging the whole process of purification. As stated by Sophia et al. (2016), sedimentation and bar screening can be largely improved and strengthened for better results. However, on the other hand, Altenburger et al. (2015), mentioned that filtration is essential and mostly necessary for efficiently separating and removing particles from the water. The fundamental of slow sand filters is mainly due to constituents of fine sand filters.

2.5 Covering materials

Covering materials are relatively important to prevent the algae from getting direct sunlight. As mentioned by van der Kooij et al. (2017), it plays an essential and vital role in preventing direct contact of algae with direct sunlight. Excessive growth and development of algae are directly responsible for direct sunlight and insufficient covering materials. Lack of sufficient amount of covering materials may impact directly on the deterioration of water quality. However, on the other hand, Corral et al. (2014) mentioned that any covering material might not be provided for attaining overall efficiency. Selection and application of a particular type of covering material are essential as well. Lack of selecting appropriate covering material may not offer the necessary results. The specification of different types of covering materials is mentioned below:

2.5.1 Partial or complete coverage

In this process, filter beds may or may not be adequately covered. Complete or partial coverage may vary depending on the situation and consideration. The strategies associated with partial coverage mainly includes building canopies and concrete decking

Complete coverage of sedimentation basins

Complete coverage of filter cells

Partial concrete deck cover

Very effective

11 (52.3%)

9 (37.5%)

4 (21%)

Somewhat effective

3 (14.2%)

11 (45.8%)

9 (47.3%)

Not applicable

5 (23.8%)

3 (12.5%)

5 (26.3%)

Not effective

2 (9.5%)

1 (4.1%)

1 (5.2%)

Total number of plants

21

24

19

Table 2: Table containing survey results on partial or complete coverage

(Source: gov.uk, 2018)

As per table number 2, the final results on complete or partial coverage are mentioned.

2.5.2 Retractable structure

This covering material offers the best possible advantage in comparison with others. The main advantage is that it may be covered and opened at any instance amount of time depending upon its requirements. An opening is mainly undertaken during its cleaning. The selection of materials for the process mainly consists of materials such that, it does not cause any reaction with the treated water and passage of sunlight is restricted. Schijven et al. (2014) mentioned that it is commonly made up of high strength fabric mainly covered over aluminium arches. These features provide easy access in case of the maintenance operation.

Figure 2.5.2: Photo of retractable structure

(Source: gov.uk, 2018)

The main advantages and disadvantages of the structure are mentioned below:

Advantages

It is successful in controlling and maintaining the growth of algae in the water. It plays an effective role in odour controlling and trapping

Effective while protecting against all possibilities of debris and accidental animal droppings

Offers sufficient amount of protection from Ultraviolet rays of the Sun, It also helps in preventing contact with water

Sufficiently durable and long-lasting as well

Causes least amount of damage and destruction to the environment

Ensures minimum and lowest possible amount of interruption and disturbance to the function of the plant during its installation

Lowers the amount of water lost during evaporation

This covering material, in spite of its advantages, suffers from numerous disadvantages stated below:

Exhibits sufficient amount of weakness in resisting strong winds and snow. As the weather condition in England is unpredictable, it may offer difficulty under this process

In case of heavy rains, there is a huge possibility of seepage or infiltrating of rains through the covers.

It may not be possible to cover up the filter for most of the time due to the emission of methane gases which may deteriorate water quality

2.5.3 Suspended coverage

This method of coverage in comparison with others offers effective coverage in proper suspensions.

Figure 2.5.3: Image of suspended coverage

(Source: gov.uk, 2018)

The main advantages and disadvantages of this process are mentioned below:

The number of losses due to evaporation from sunlight is prevented. As a result, the amount of solar radiation and the temperature of the water is lowered

Captures and traps presence of any odorous gases

Offers sufficient amount of restriction in promotion and growth of algae

Offers minimum amount of disturbance to the plant function during its installation and operation

Offers sufficient amount of low cost in the maintenance operation

Offers sufficient amount of restrictions for entering the debris

Prevents any further growth and development of algae

The disadvantages of the process are mentioned below:

Effects and not allow to escape harmful gases such as methane which deteriorates the quality of water

Offers significant amount of difficulty in accessing water for inspection and cleaning

2.5.4 Floating covering material

This covers plays an important and essential role in offering protection from sunlight. It uses comparatively floating matter to be used for covering. The covering material may consist of flat or rounded sheets which float on water surface. It does not allow complete coverage as it allows passage of harmful gases.

Figure 2.4: Image of floating coverage

(Source: gov.uk, 2018)

The advantage of the process is mainly as follows:

High adaptability and preferable in a wide range of site situations

Ensures minimum amount of possible evaporation

Does not require any special skills and requirements for operation function

Plays an important role in preventing any algal growth

Long-term life expectancy which can exceed twenty years

Protection against debris

Can be installed in plants which already exist

The main disadvantages are;

Access to water for cleaning and another inspection purpose

Imprisoning harmful gases such as methane degrades water quality

2.6 Factors mainly influencing the cost of the slow sand filter

The slow sand filter is mainly influenced by some different factors based on the following matters:

Cost of the structure: The cost of the structure to be encountered in the overall process is of sufficient importance. As commented by Peng et al. (2016), cost of structure mainly involving individual filter beds and single structure comprising of different filters are different. The costs associated with structures consisting of permanent nature are a one-time investment and beneficial in the long run. On the other hand, Pizzolatti et al. (2015) mentioned that cleaning mechanisms for the structure are essential as well.

Cost of labours: The price or the cost of labours plays the essential role in selecting the type of structure. As mentioned by Magic-Knezev et al. (2014), the covering materials and the mode of covering directly influences on the overall cost of the structure. Covering of the filter prevents contact of sunlight with algae which prevents its overall growth and further development. This tern lowers the amount of labour cost.

Impacts of cleaning: As mentioned by Pompei et al. (2017), cleaning and maintenance costs primarily affect the cost of the structure in the long run. Different cleaning methods have its advantages and disadvantages. Proper selection and application of low cost and valuable cleaning methods are essential for long-term benefit and assurance.

2.7 Cleaning mechanisms of the filters and justifications for its usages

The cleaning procedure of filters plays an essential and important way for pointing and analysing possible cleaning mechanisms at Kempton water works. The main purpose is mainly to analyse the importance of cleaning mechanisms and to point out the best one.

2.7.1 Robotic cleaning mechanisms of algae and schmutzdecke

Robotic cleaning mechanisms ensure the highest possible quality of treatment and removal of schmutzdecke and algae. The frequency of the amount of cleaning and maintenance of water depends upon water quality. The main advantages of robotic and mechanical cleaning are highly user-friendly and reliable to work. Being operated by computerised sensor operation, any manual inspection is eliminated. The inspector or observer is allowed to take a close watch and monitor any obstacles in the path. It does not require any drainage function for operation or the notification and awareness level is sufficiently higher. Auto cleaning mechanisms reduce cost due to labour. Whereas certain limitations are there like largely dependent upon electric power, the main operations may shut down in case of power failures. Amount of power consumption is sufficiently higher and loss of water due to sludging and sucking water particularly at the same time onwards or blockage of the hose is a big problem.

2.7.2 Scrapping and backwashing

During the filtration process, the water is flowed and passed down from the filter bed. During its passage, deposition of precipitates such as schutzdecke is deposited on the top of the filter bed. Zaman et al. (2017) mentioned that oxygen promotes the formation of schutzdecke. Presence of oxygen in water promotes its formation. It is necessary to be removed to ensure the best quality of water.

2.7.2.1 Scrapping process

The scrapping action of cleaning is one of the most simple and effective methods of cleaning processes. However, Altenburger et al. (2015) mentioned that scraping action is labour intensive and it sufficiently costs a lot due to its frequent maintenance operations. The area and size of filters especially at Kempton water work plant of sufficiently large. As a result, it may not be feasible to offer scrapping process. Whereas Zaman et al. (2017) claimed that scrapping process apart from that takes a lot of materials from the filter which is to be filled at regular intervals which takes away additional cost. It mainly implies that larger size of the filter may not promote scrapping.

2.7.2.2 Backwashing process

The process associated with backwashing is relatively easier and effective methods. It is the alternate solution for cleaning. In this process, water is blown in a backward direction to remove the presence of any major clog in the filter. The cleansing liquid is released in reverse direction and the period of backwashing is mainly kept between 24 to 72 hours depending on the situations and considerations.

Figure 2.7: Backwashing process

(Source: gov.uk, 2018)

Studies and consideration of past researches illustrate the importance of backwashing rather than scraping. Among which three filters are backwashed while remaining three are scrapped, efficiency is mainly achieved in backwashing rather than scrapping.

2.7.3 Chemical treatment process

Apart from above factors, several chemicals may also be used in the water for undergoing treatment process. Zaman et al. (2017) mentioned that different variety of chemicals such as lanthanum and alum solution is added to the water for treatment and also the removal of particles such as schutzdecke and algae. Herbicides are mixed in the waste water to control the growth and development of algae up to certain limit. Other important chemicals are copper sulfates. The most common chemicals which may be used are stated below:

2.7.3.1 Copper sulfate

It is mainly inorganic compound consisting mainly of copper and sulfur in a proper promotion. It is quite successful in reducing the effects of algae. The advantages and disadvantages are it is available widely with relatively economical and cheap prices and is relatively easier and has a simple application, effective in removal of algae from the raw water also. On the other hand, certain disadvantages are there like it is sufficiently toxic and impose undesirable properties in raw water and are costly as the cost of chemicals are sufficiently higher.

2.7.3.2 Ozonation

It is modern water treatment as it involves the interaction of ozone with raw water. The advantages and disadvantages of the process are it can react quickly to virus and bacteria, effective in removal of disturbing taste and colour and eliminates the necessity of adding chemicals to the water.

Figure 2.7: Ozone Treatment

(Source: gov.uk, 2018)

However, it has some disadvantages like the cost of equipment is sufficiently higher and requires a high amount of energy for its operation. Ozone may react with the presence of sufficient amount of chemicals in the water

2.7.3.3 Aeration treatment

The process of aeration treatment mainly includes the interaction of oxygen with water. It actively involves increasing the levels of amount of dissolved oxygen in the water. Aeration is mainly performed in aeration basins and tanks. The advantages and demerits of the process are it is relatively environmentally friendly and does not impact much on water quality and removes the necessity of chemicals for algae treatment. Larger surface area requirement is sufficiently larger with expensive in operation and maintenance or uncertainty in efficiency.

Figure 2.7.1: Aeration basin

(Source: gov.uk, 2018)

However, chemical treatment may not be applicable for usages at Kempton water parks. The main reason is to its adverse effects on the quality of water. The quality of water undergoes sufficient amount of deterioration due to the influence of chemicals making it unsuitable for human consumption. Water from Kempton water treatment is mainly responsible for sustainable needs of the population at Surrey. As a result, presence of excessive chemicals in treatment may render unfit for human consumption. In addition to it using certain volumes of chemicals on a regular basis involves a large amount of cost, which adds the overall cost of the maintenance operation. Owing to its severe disadvantage and its cost, it may not be possible for adopting in Kempton water works.

2.8 Treatment methods

Methods in treatment process involve the following procedure. The following flow diagram indicates the procedure to be followed for water treatment.

Figure 2.8: Water treatment process

(Source: gov.uk, 2018)

The above figure indicates the procedures and process to be followed for water treatment. The first steps involve taking the water from the source of water. As claimed by Magic-Knezev et al. (2014), raw water does not only pass through filtration to ensure complete treatment. It relatively undergoes different stages of treatment to arrive at most appropriate treatment. However, on the other hand, Grace et al. (2016), commented that filtration is one of the essential processes which promotes overall efficiency. Filtration is one of the most important and fundamental aspects necessary for water treatment before it undergoes disinfection. Figure 2.8, indicates the sequence of stages passed by raw water to arrive at final treatment.

2.9 Literature gap

While performing the research work, the presence of certain amount of gaps is identified. During the stage of water purification, the primary chemical reactions which are subjected are not attended. Presences of other treatment means which may be used alternatively to lower or reduce the liberation of harmful gases are not completely analysed. In addition to it, importance and impacts of covering material are properly not attended due to lack of proper information. Gap and lack of access to knowledge have offered restrictions for quality research.

2.10 Summary

This section effectively plays an essential and important role in pointing out the different scope of treatment procedures at Kempton water works. The impacts of different treatment methods are discussed in the process. The different stages on which water passes are to ensure maximum efficiency in water purification. Apart from that, the essentials of covering and maintenance work are obtained from this section. Summary of overall findings indicates the efficiency and impacts of different factors in the achievement of overall results.

Chapter 3.0: Research methodology

3.1 Introduction

The main process in the study plays an essential and important role in pointing out the research methods to be performed in research work. It consists of different tools that need to be analyzed for bringing the best possible solution. It consists of different procedures and cost of chemical treatment necessary to be developed for obtaining overall efficiency in treatment.

3.2 Cost of the cover

Covering is one of the most essential and important mediums for preventing the algae to establish direct cost with the rays of the sun. Zaman et al. (2017) mentioned that sunlight largely favours the growth of algae which are difficult and costly to remove upon cleaning. Studies from the above section illustrate the types of covering material and its application in different situations. Three different types of covers are mainly discussed in the study. The different types of covering materials and systems in the process necessary. Floating and suspended covering mechanisms are difficult, and it may not be possible to be adopted particularly when it is to be used for regular cleaning operations. The potential economic solution may be of retractable cover. The reason is due to its easy opening and closing operation. Easy opening operation facilitates regular cleaning and maintenance operation. Rolph et al. (2014) suggested that modern retractable covering mechanisms are mainly formulated with fabric medium. Fabric retractable covers are widely preferred as it favours easy opening and closing. This type and kind of cover may be performed due to the presence of GTI Company able to offer good quality and affordable fabric.

In Kempton waterworks, there are 12 different filters. The dimensions of the filter are generally of a size of 42*60 square feet dimensions. The covers are brought from GTI business enterprises and are bought at a rate of 26, 000 pounds/Square feet

Cost of labour = 600 pounds per square feet

As a result, the overall cost is 260000/(12*42*60)= 8.59Pounds/square feet

Total square feet of the structure = 2810.88-meter square or 30256 feet square

Total cost for the structure = 259899 pounds

Name of cover

Type

Cost per m2 (Pounds)

AquaCap™)

Floating

22

E-VapCap

Floating

6

NetPro

Suspended

8

SuperSpan

Suspended)

30

Table 3.2 Costs for cover

(Source: learner)

3.3 Robotic method of cleaning of schutzdecke and algae cost

The cleaning methods and process associated with robotic mechanisms are of sufficiently higher than another cleaning mechanism due to its feasibility in the cleaning process. The cost particulars and specifications are mentioned below:

Particulars

Price Range

Average price

Mechanical dredging costs for sludge (algae and schmutzdecke)

Pounds 220 and $337

278.5

Collecting and dumping costs

$60 per ton

Total cost per ton is $388.5

Duration of the procedure = 2 weeks

Per year requirement

Pounds 9324 per ton

Table 3.3: Robotic cleaning mechanisms

(Source: learner)

The amount of cost necessary per annum amounts to up to 9324 pounds per ton in the case of robotic treatment.

3.4 Cost of chemical treatment

The general requirements of different chemicals for treatment process are mentioned in the below table:

Algaecide

Annual Cost (Pounds)

chlorine

389,000

copper sulfide

42,000

Potassium permanganate

862,000

active CU++ ion

38,000

Table 3.40: Cost table of different chemicals

(Source: learner)

Table number 3.40 mainly indicates the types of chemicals to be used, and the price of respective chemicals to be used in the overall treatment process are mentioned. Among which it is noted that the price of chlorine is of sufficiently higher in comparison with other products. The process in Kempton waterworks may not permit the use of chemicals for treatment. The main reason is mainly due to the high amount of investment in chemicals and adverse effects on the quality of water as well.

3.5 Cost of algae aeration

The cost mainly associated with algae aeration is of sufficiently significant to determine the factors which may increase overall efficiency. The principal operations of sand filters mainly depend upon the operation and concentration of microfibers.

Figure 3.5: Algae concentration and types

(Source: gov.uk, 2018)

The costs associated with algae aeration depends on many factors such as:

The utility of mechanical aerator devices

The cost utilised in development and maintenance operation

Complicacy of the unit

Availability of power source

Energy consumptions and savings

On the availability of the relevant factors and scope of development, the concentration of algae may be widely performed and utilised for ensuring overall efficiency.

3.5.1 Cost of algae aeration

The process associated with algae plays an essential and important role in aeration process. The cost necessary in this process is sufficiently higher in comparison with other methods. The cost distribution for aeration mechanisms are stated as below:

Equipment necessary

Per unit cost

Overall cost required

Aeration basins construction

200 pounds for each filter

200 * 12 = 2400

Piping mechanisms

50 pounds of piping

50 * 6 = 300

Diffusers

60 pounds of 12 diffusers in each tank

60 *12 = 720

Blowers

Six blowers each for 160 pounds

6 * 160 =960

Maintenance Cost

300 pounds for yearly maintenance cost

300 per year

Total Cost

4680 Pounds per year

Table 3.5: Cost of basic requirements of aeration

(Source: Learner)

The process from the above table indicates the per unit cost of overall units necessary in aeration process and the overall cost necessary

3.6 Cost of sonication

Sonification is one of the most advanced and modern technology to be adopted in the treatment process. As stated by Altenburger et al. (2015), it plays an essential and fundamental role in offering treatment based on ultrasound technology. The different apparatus necessary for the process are mentioned below:

Requirements of ultrasound apparatus

Standard dimensions

Size required

250*130*90 cubic centimetres

Frequencies necessary

130 KHz and 35 KHz

Transducer requirements

2 Nos piezo metric transducers

Power input for each mechanism

500 watt each

Table 3.6: Apparatus requirements for sonification

(Source: Abokifa et al. 2016, p.120)

The efficiency and effectiveness of sonification mainly depend upon the amount of power available and may be effectively generated on the field. As mentioned Douterelo et al. (2016). , the price of operation depends mainly upon the size and volume of filter areas. On the other hand, stand Peckham et al. (2015) expressed that location determines a key factor. As Kempton waterworks is mainly located far away from industrialization, the cost associated with

The cost breakdown structure is mentioned below:

Major specifications

Associated costs

Overall costs

(Pounds)

Cost of all technical hardware

6000 pounds

6000

Cost of installation

5400 pounds

5400

Maintenance cost

956 pounds (monthly cost)

11472

Electrical cost

352 pounds (Monthly cost)

4224

Overall Cost

27096

Table 3.6: Table of cost specifications

(Source: Learner)

Apart from heavy consumption of electricity, sonification also depends upon different water qualities and parameters which are mentioned below:

Influence of pH

The value of pH of the water which when greater than 0.05, no considerable effects are obtained

Influence of temperature

As per research, it is noted that temperature of the water undergoes increment with sonification.

3.6.1 Cost of the permanent structure

The emphasis on constructing permanent structure over the filter is one of the most important and permanent solutions to be provided (Abokifa et al. 2016). The emphasis on providing permanent structure essentially provides two different benefits, which is low cost and one-time investment or hassle-free. The major works at Kempton waterworks are important to be offered permanent structure devoid of any covering material.

Figure 3.6: Permanent structure in a slow sand filter

(Source: gov.uk, 2018)

It consists of a simple structure made either of concrete or brick masonry depending upon its availability. As commented by Bond et al. (2015), permanent structure in addition to others helps to prevent falling of foreign materials in raw water. Influence of foreign particles puts pressure on cleaning mechanisms including jamming filter. However, on the other hand, Castiglioni et al.(2015) mentioned that it suffers from a certain amount of disadvantages such as it does not allow harmful gases such as methane to escape causing negative effects on the quality of water.

To solve the problem, construction of flumes is necessary to be made, which is an additional expense. The cost of the filters is represented below:

Requirements

Quantity

Per unit cost

Overall cost

Size of filters (42*60 square feet) each

12 filters

Cost of bricks

173 pounds

Cost of cement

100 pounds per bags

Labour charges

Table 3.6: Cost specifications of the permanent structure

(Source: learner)

Requirements

Rate of unit

Overall cost

281 cubic meters

Brick requirements’ = 112400 numbers

173.02 pounds per 1000

19467.68 pounds (One time investment)

Cement requirements = 3000 Cubic meter

Table 3.6: Cost specifications of permanent structure

(Source: learner)

Considering the size of bricks in the UK = 215*102.50*65mm

42 feet in mm = 12801.60 or 12.80 meters

60 feet in mm = 18288 or 18.30 meters

Area of the structure = 30240 square feet (12*42*60)

Area for one filter = 12.80*18.30= 234.24square meters

Area of the structure = 12* 234.24 square meters = 2810.88 meter square

The volume of the permanent structure essential = Depth of the structure to be provided as 0.1m consisting of the thickness of covering material such as cement mortar.

The volume of works = 2810.88 * 0.10 = 281 cubic meters of works to be done in the overall structure.

Requirements of number of bricks

Volume of one bricks =0.2*0.1* 0.06 cubic meter

Assuming 17.5 mm mortar and lining materials on both sides

Volume with mortar = 0.1+0.035 = 0.135 & 0.06+0.035 = 0.095, which is 0.2*0.135*0.095= 0.0025 cubic meters

Number of bricks necessary for completing the work of 1 cubic meter= 1/0.0025= 400 Nos

Total number of bricks = 400 * 281=112400 numbers

Cost of backwashing

The process associated with backwashing plays an important and essential part of ensuring overall cleansing mechanisms. The costs associated with backwashing process are sufficiently lower than other measures. Backwashing costs mainly involve the force of water to be allowed in reverse direction, which makes use of higher electrical power. The breakings down of all costs are mentioned as below:

Parameters for operation

Costs necessary in the process

Yearly costs

(Pounds)

The motor power necessary for reverse circulation

750 pounds per watts

(4 months interval)

2250

Additional cost for water requirements in cleaning

721 pounds

(4 months interval)

2163

Electric power consumption

3200 pounds

3200

Labour action for manual removal of all flocs

3600 pounds per square meter (Yearly costs)

36000

Total costs

43613

Table 3.6: Cost specifications for backwashing

(Source: learner)

The techniques and process associated with backwashing mainly involve motor power and energy for recirculation the water reversely. The water upon its reverse direction brings out the disposition of floc particles which are removed by manual means. In Kempton waterworks, the area is sufficiently larger, and there are 12 numbers of filters each. As a result, it may not be feasible enough to implement backwashing process for all filters.

Cost of scrapping

The costs mainly associated with scrapping are intense. Breaking down of the amount of labour and cost in the process, investment on the removal of schmutzdecke and algae from the filter is labour intensive and costly. Summing up the costs, it is observed as follows:

Cleaning parameters

Costs (4 months interval )

Overall costs (per year)

Preparation for drying Schmutzdecke

12600 Pounds/ square meter

37800

Manual labourers in scarping operation

5600 pounds/ cubic meters

16800

Disposition of materials in the truck

(including transportation costs)

1890 pounds/ cubic meters

5670

Refilling of scrapped sand + cost of sand

5230 pounds/ cubic meters

15690

Total costs

75960

Table 3.6: Cost specifications of scrapping

(Source: learner)

The steps of operation in the above process indicate the steps and stages of cleaning operation. The scrapping operation removes sufficient amount of filter media from the filters. It arises an additional cost of filling cost and scrapping as well. The impacts of both costs involve deviation of additional costs for Kempton, which adds problem for bearing.

3.7 Water quality

The water and its quality are one of the essential requirements in return of its investments. The water quality parameters are maintained based on qualitative and quantitative consideration. As mentioned by Jiang et al. (2015), parameters on the quality of water in the water works are essential for ensuring the maximum amount of efficiency regarding its safety. The quality of water at Kempton is mainly affected by influence and reaction of algae which deteriorates the quality of water. Lack of allowance and passage of gases such as methane influences water quality. The efficiency and effectiveness of sonification mainly depend upon the amount of power available and may be effectively generated on the field. As mentioned Xue et al. (2014), the price of operation depends mainly on the size and volume of filter areas. On the other hand, Jiang et al. (2015), expressed that location determines a key factor.

3.8 Chemical tests

Chemical parameters of water quality involve the following considerations:

pH value: It is necessary for the water output to have the value of pH ranging from 6.5 to 8.50. However, pH value of 7 is largely acceptable.

Amount of BOD: The value of BOD indicates the amount of organic activity. Yang et al. (2015) mentioned that higher the amount of BOD, the higher the amount organic particles in the water. The amount of organic content is ensured as well. As commented by Jiang et al. (2015), higher values of the amount of consumption of dissolved oxygen than the amount of water supplied, algae formation is encouraged. The amount of dissolved oxygen in water controls BOD and consequently on algae formation.

3.9 Physical test

Physical tests are mainly conducted for determination of essential physical properties. Physical properties such as colour, odour, taste, and turbidity of the water indicate the physical properties and characteristics of water.

3.10 Bacteriological tests

Tests for bacteria play an essential an important role in removing the number of bacteria and

other harmful particles. Observation for the presence of any harmful bacteria is essential for ensuring the sustainability and purity of water. Yang et al. (2015) mentioned that proper tests are essential and important to be performed for removal of any harmful bacteria present.

3.11 Timeline

(Refer to Appendix 1)

3.12Summary

The process from this section plays an efficient and essential role in highlighting the different amount of costs associated with each process. Findings from the portion indicate influences of different costs on treatment and the overall economy as well.

Chapter 4: Data findings and analysis

4.1 Introduction

The main strategies and policies in this section will mainly focus on the representation of analysis of data collected from the previous sections and apply in the present context to determine the efficiency regarding cost-effectiveness and its value. The analysis in this section will actively focus on determination of best possible design mechanisms to be used in Kempton waterworks.

4.2 Secondary analysis

This study will mainly focus on secondary analysis to derive the best possible solutions for analysis. It consists of research studies from authentic and reliable sources of data such as journals, research publications to derive highly reliable and authentic sources of data.

4.2.1 Importance of permanent solution

As mentioned by Zyara et al. (2016), the cost of construction of the permanent structure is relatively cheap in comparison with other costs that are enquired for manual cleaning and maintenance. It does not allow the sun to come in direct contact with the raw water which prevents the growth of algae and results in low maintenance cost. Sunlight is the direct source of growth and development of algae. Santana et al. (2014) mentioned that permanent covering eliminates all possibilities of interaction with external rays of the sun.

In Kempton waterworks, the permanent structure is mostly suited as it is one of the most reliable means of operation. Unlike retractable covering, it does not take a lot of time during opening and closing. Chemical treatment also offers a better solution. Whereas, Luby et al. (2015) commented that influence of excessive maintenance cost and the probability of hazardous effects on the drinking water makes it largely unpreferable.

Figure 4.2: Illustration of different filers at water works

(Source: Learner)

AutoCAD drawing as per Figure 4.2 and 4.2.1 plays an essential and important role in showing the arrangement of possible filters at Kempton waterworks. The total number of filters at Kempton is of 12 in numbers and is larger. Use of retractable cover is not preferable, owing to the time wasted in opening and closing. Hence, provision of the permanent structure is mainly preferable in this case. The covering material for each structure or filter may not be cost-effective, and there lies possibility of seepage of rainwater through the structure. To solve the problem, two long stretch of masonry structure is sufficient and cost-effective.

Figure 4.2.1: Illustration and dimensions of the single filter

(Source: Learner)

The above figure shows and indicates the dimensions and thickness of a single filter.

4.2.2 Analysis of cost of all probable solutions

In this process, the influence of all major cost considerations to be encountered in the overall process is illustrated. The cost analysis for likely solutions is explained below:

4.2.2.1 Cost Analysis – 1

Covering material

The costing necessary for covering material is illustrated in previous sections. It is noted that cost associated with retractable and suspended covering material are represented from the graph below:

Figure 4.2.3: Cost of covering material per square meter

(Source: Learner)

Based on above chart, the cost for suspended covering material is represented. It is noted that suspended covering materials cost highest from the business enterprise named as SuperSpan. However retractable covers obtained from GTI ventures costs nearly of about 8.59 pounds per square feet. However, these types of covers are not overall suitable to be provided.

4.2.2.2 Cost Analysis – 2

Chemical requirements

Figure 4.2.4: Annual costs of chemicals in pounds

(Source: Learner)

The above figure indicates the number of chemical requirements annually. It indicates that potassium permanganate costs the highest.

4.2.2.3 Cost Analysis – 3

Aquatic aeration methods

Figure 4.2.5: Cost of particulars for aeration

(Source: Learner)

The overall cost for each of specified details for aeration is mentioned above. The maximum amount of cost is mainly enquired in the construction of aeration basins. Apart from that, it requires maintenance cost of 300 pounds per year.

4.2.2.4 Cost Analysis – 4

Sonification

Figure 4.2.6: Cost of particulars materials for sonification

(Source: Learner)

The above analysis mainly indicates the cost of respective items necessary for sonification. Report from estimates illustrates that yearly cost to be 216 pounds for maintenance purposes. The total amount of cost is of 1711 pounds.

4.2.2.5 Cost Analysis – 5

Cost of the permanent structure

The main requirements of the permanent structure are the number of costs inquired on bricks. Results implied that the cost of bricks amounts to about 19467.68 pounds for the total number of bricks. The cost is a one-time investment and devoid of any additional cost in the lifetime.

4.2.2.6 Cost Analysis – 6

Cost of scrapping

Figure 4.2.7: Cost for scrapping

(Source: Learner)

The above figure plays an essential and important role in showcasing the individual costs necessary for scrapping. It is noted that the highest possible cost is directly subjected to manual labours and refilling of sand due to loss upon removal of sand. The total amount of cost mainly adds to 75960 pounds. The amount of cost in the process is not feasible for working at Kempton water works.

4.2.3 Efficiency analysis regarding potential solutions

The potential solutions for each cost necessary for cleaning and maintenance mechanisms are indicated and presented below:

Essential cost parameters

Price (in pounds)

Grade

Costs for backwashing (Yearly)

43613

B

Cost necessary for performing sonification (Yearly)

27096

C

Cost requirement for constructing the permanent structure

24650.63

A

Cost requirements for performing algae aeration (Yearly)

4680

D

Costs associated with robotic cleaning mechanisms (Yearly)

9324

E

Costs to be undertaken for chemical treatment (Yearly)

665500

F

Table 4.2.3: Cost specifications for each task

(Source: Learner)

Figure 4.2.3 Graphical representation on costs

(Source: Learner)

Studies from the above table mainly indicate the different cost specifications necessary for respective items. The above figure mainly indicates the cost required for respective items. Among all the costs, the amount of money to be encountered in the permanent structure is of one-time cost, whereas other costs are based on yearly. Construction of permanent structure does not require any yearly maintenance cost; as a result, it is cost effective above all. Yearly investment in maintenance such as scraping and only backwashing process may not be overall suitable for Kempton waterworks to bear.

In addition to it, chemical treatment costs are sufficiently higher, and it affects a lot of the health conditions of the consumers. The most senior possible grade is mainly towards the permanent structure for overall effectiveness as the amount of money to be spent in the long run is comparatively higher than the value added.

4.2.4 Application of decision matrix to identify the best solution

Decision matrix plays an effective and important role in pointing out and highlighting the main decisions for each respective idea. The following decision matrix is illustrated below:

Parameters

Cost

Value delivered

Efficiency

Overall outcome

Permanent structure

A

A

A

99%

Manual treatment

B

C

C

80%

Chemical treatment

D

B

B

75%

Algae aeration treatment

C

C

D

70%

Sonification

D

C

D

60%

Table 4.2: Decision matrix and efficiency

(Source: Learner)

The main indications from the table illustrate the importance of permanent structure in ensuring overall efficiency and effectiveness. The concept of permanent structure is most appropriate in comparison with other means. The results from the above table indicate that permanent structure is safe and better from all perspectives. Yangn et al .(2015) mentioned that permanent structure apart from that is one of the most effective structures regarding its overall benefits.

4.2.5 Design of the structure

Figure 4.2.5: Sections in the filter

(Source: learner)

The above figure mainly indicates the sequence of stages of different layers of filtering media through which water passes to encounter final treatment. The top layer is its covering which includes covering structure made up of masonry or concrete structure. The above structure is provided for covering. The next layer consists of fine sand attaining a particular area. The next layer includes gravel. Beyond this layer, fresh water is allowed to pass through under drains.

4.2.6 Cost of the structure

The overall costing of the structure is mainly dependent on different specifications and different work process in work. Different items and specifications have an individual cost on the overall structure. The different activities involved in the construction of slow sand filter are mentioned below:

Activities

Cost (pounds)

% of the overall cost

Earthworks

Earthwork in excavation

In filling

34723.11

9.04

Concreting for 12 filters

Concreting work inclusive of

Reinforcement

Formwork

Concrete

182668.76

47.60

Manual mechanical instruments

Materials

Installation systems and tools

Testing materials

38170.24

9.93

Electrical costs

Costs for electric machine operation

Costs of backwashing

30000

7.81

Covering using plaster

Interior plaster consisting of water and chemical resistant properties

(Inclusive of corrosion protection painting material)

13500

3.514

Exterior plastering

(Normal plaster with a ratio of 4:1)

9643.30

2.51

Filtering media for 12 filters placed individually

Coarser filtering media (layers of gravel)

Layer- 1 (Gravel of 2120 square meter)

Layer -2 (Cross-sectional area of

Layer -3

25080.65

6.53

Fine filtering

Fine Sand

16256.23

4.23

Cleaning mechanisms

Cleaning using backwashing

31320

8.15

Cost of placement of filter media

2726.03

0.71

Overall cost

384088.32

Table 4.2.6: Cost specifications for respective items

(Source: learner)

The above table plays an essential and important part in analysing costs associated with all components. The cost mainly associated with concreting encounters highest possible cost. The cost associated with concreting of 12 filters encounters the highest amount of cost in comparison with others.

4.2.7 Influence of water quality

The water quality plays an essential and important role in pointing out the factors affecting water quality on overall cleaning mechanisms. As result of the formulation of Schmutzdecke, the quality of water is sufficiently affected. As a result of the formation of the material, the passage of raw water gets blocked and is not allowed to pass for further filtration which mainly results in blockage and results in deposition of water. Xue et al. (2014) mentioned that the water as a result of blockage fails to pass through the filter. Sensor helps to determine the head of water. Presence of any major changes in water levels aware the system to make necessary operations. Backwashing any other cleaning mechanisms are performed when the head of water rises above standard limits. The quality of water is sufficiently affected by the amount of material deposited.

Filtration is mainly undertaken at the final stage of water treatment plant after it passes through another preliminary process. The filter may be classified on the basics slow and rapid sand filter. Slow sand filter mainly consists of finely separated by fine sand or gravel. Huge requirements of labour for cleaning operation increase the cost of maintenance.

4.3 Summary

This section mostly plays an essential role in pointing out the factors affecting different materials necessary for covering. In addition to that, it effectively analyses the importance of cleaning mechanisms in the process. Findings from the section indicate that permanent structure provides excellent and effective possible solution requiring only one-time investment.

Chapter 5: Conclusion and recommendation

5.1 Conclusion

The primary process in this study plays an essential and vital role in discussing and analysing the best possible solution for covering at Kempton waterworks. It has been conducted an exhaustive analysis on pointing out the fundamental solutions necessary to be developed for overall cost savings. Covering material and differences in covering techniques plays an essential role in offering quality services at low price. Cleaning and maintenance techniques at slow sand filter are the relatively more significant issue faced by owners. Construction of permanent structure effectively plays an essential part in breaking the contact between direct rays of the Sun and raw water. Findings and analysis from the study illustrate the cost specification for each covering material and methods of treatment applicable at Kempton waterworks. It will help the users in understanding the factors which mainly influences the cost of slow sand filters. Overall findings and analysis from the study indicate the importance of covering filters for preventing the growth of algae.

5.2 Linking with objectives

Objective 1

To link this objective, in 1.5 working procedure of slow sand filter has illustrated that mode of functioning and operation of the slow sand filter. It indicates that slow filter is a direct method of water treatment. The considerations from literature review also show different perceptions of different researchers to attain the working procedure and functions of the filter. Slow sand filter mainly includes two main storage sections. Raw water is allowed to enter through one section with filter beds on other section through which water is passed. Filterbeds consist of filter media comprising of fine and coarse-grained particles.

Objective 2

To link with this objective, in 3.2, 3.3, 3.4 and 3.5 different factors which mainly promotes in an increase of cost of the slow sand filter are discussed. Overall cost depends upon the covering material selected. It is indicated from this section that suspended covering material costs the highest.

The influence of cleaning mechanisms such as mechanical and robotic methods and successive costs for each is illustrated in 3.3. Likewise, 3.5 states the costs to be encountered for modern techniques such as aeration and sonification.

Objective 3

To link with this objective, in 2.6 the factors which are mainly responsible for the cost of the filter are discussed. Improvement in cleaning and maintenance techniques helps to lower significant amount of cost in cleaning. The importance regarding rates of labour in maintenance operation is highlighted in the section. In addition to that in 3.2, 3.3, 3.4 and 3.5, the different parameters responsible for cost are illustrated. Controlling and monitoring these costs impacts on overall savings.

Objective 4

To link with this objective, in 2.5 the different types of covering materials are discussed. The costs and effectiveness of complete or partial coverage are important. The importance of retractable structure, suspended and floating matter is analysed in the section. The cost distribution for each structure illustrates the cost distribution of covering material regarding its working principles and mode of its operation.

5.3 Recommendation

The major work functions at Kempton waterworks may be improved to a certain extent by following best economic principles and techniques. The following recommendations may be used for overall improvement:

Adopting permanent structure: Construction of permanent structure is the one-stop solution for working at Kempton. It eliminates all possible causes of hassles in cleaning and maintenance. Unlike retractable covering, it does not take sufficient amount of time in opening and closing. As a result, it is necessary and must be provided as a one-time investment on permanent structure, and yearly investment on cleaning and maintenance on different temporary structures are different from each other regarding cost.

Periodic cleaning mechanisms: Removal of schutzdecke and algae from the filter are important and must be performed periodically. Backwashing must be effectively performed twice in a year to avoid long-term cost and difficulty in removal. Backwashing involves the reverse operation of water which is eliminated from the filter from outlet pipes. The cost and maintenance for backwashing are low and hence must be followed

Maintaining water quality: The water quality must be maintained in all stages of purification. All major characteristics of water such as chemical and physical characteristics of water must be verified and maintained to ensure least possible damage and pressure to filter. The quality of water entering the filter must be devoid of physical characteristics and particles.

Minimising cost of electricity: The costs associated with electricity and electrical power must be minimised by promoting and encouraging gravity flow. Flow under the influences of gravity encourages overall costs in savings. Flow under the influences of gravity ensures the minimum amount of usage of electric power. The arrangements of treatment process must be developed in such a way such that the water can flow from one section to another under the influence of gravity.

5.4 Limitation

The research conducts an efficient and important role in identifying the main cost requirements at Kempton waterworks. However, certain limitations related to lack of necessary data in the form of the effluent parameters and the amount of water to treated are encountered. Apart from that, it is also observed that few journals are not investigated due to lack of financial resources. Moreover, it is noted that necessary information is available in few journals, which are not sufficient for complete analysis. Shortage of data is a major constraint which has affected the quality of this work. Another major limitation is the research does not have sufficient amount of time to analyse all considerations.

5.5 Future scope of the study

This study effectively plays an essential and important role in highlighting the importance of different properties associated with covering materials. Identification of different types of covering materials is necessary and important to be determined for improving its efficiency in future. This study helps actively to identify and assess the required steps to be undertaken to strengthen cost related effective solutions. Cleaning and maintenance operation on a regular basis increases overall maintenance cost. This study offers specific techniques for estimating the costs and minimising its effects. In addition to that, future specifications and scope of the study illustrate the importance of gravity flow mechanisms in order to reduce sufficient amount of costs due to pumping. This study lays forward effective stages and steps to be followed and conducted for ensuring overall effectiveness for future improvements. The present process in the study efficiently plays an essential role in making sufficient amount of awareness to the users regarding the essentials of water quality in offering maximum efficiency. The arrangements of treatment process are necessary to be improved in such a way such that the water can flow properly.

Reference list

Abokifa, A.A., Yang, Y.J., Lo, C.S. and Biswas, P., 2016. Water quality modeling in the dead end sections of drinking water distribution networks. Water research, 89, pp.107-117.

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Appendices

Appendix-1

Activities

Week 1 to 3

Week 4 to 8

Week 9 to 10

Week 11 to 17

Week 18-21

Week 22 to 23

Week 23

Week 24 to 28

Selection of the site

Costing

Rentals

Construction

Recruitment of workers

Equipment purchasing costs

Raw materials purchasing costs

Testing the concrete