WO2015125063A1

WO2015125063A1 - A method of purification of water and an apparatus therefore

Info

Publication number: WO2015125063A1
Application number: PCT/IB2015/051149
Authority: WO
Inventors: Mohd Arshil MOIDEEN; Mohd Adlan ADNAN; Syamsul Ariff SUPAAT; Kok Ping VOON
Original assignee: Puncak Niaga Holdings Berhad; Ministry Of Defence Malaysia
Priority date: 2014-02-19
Filing date: 2015-02-17
Publication date: 2015-08-27

Abstract

A method and apparatus for purification of raw water is disclosed. The method comprises the steps of adding and mixing pre-treatment chemical such as alum into a first tank containing raw water, allowing flocculants in the pre-treated water in first tank to settle, pre-straining the settled water in the first tank and transferring the latter into a second tank containing bio-sand filter and introducing the filtered water from the second tank into a UV disinfectant unit. The invention further discloses an apparatus for purification of water comprising at least two tanks assemblable on a frame support, a pre-strainer unit to receive pre-treated water from the first tank, a bio-sand filter media arranged in the second tank, a disinfectant unit to kill living microorganisms and a mixing means to mix pre-treatment chemical and water in the first tank. The mixing means and the UV disinfectant unit are powered by a solar panel energy source.

Description

A METHOD OF PURIFICATION OF WATER AND AN APPARATUS

THEREFORE

FIELD OF INVENTION

The present invention relates to a method of purification of water and an apparatus therefore. More particularly, the invention relates to a method of purification of water utilizing a bio-sand filter and to an apparatus for the method, which apparatus is easily assembled, portable and is capable of being safely air-dropped.

BACKGROUND OF INVENTION

Availability of safe drinking water is essential for healthy living of human beings. Water purification is essential as un-purified water may contain bacteria, viruses, toxins, dissolved heavy metals and other forms of dissolved impurities which when consumed may be adverse to the health of the population and may also propagate water-borne diseases.

However, in remote or underdeveloped areas and in situations like humanitarian crises including armed conflicts, epidemics, famine, natural disasters and other major emergencies access to safe drinking water is limited. In such situations the population has to resort to raw water or stagnant sources of water such as groundwater, lake water, a stream, a river or the like. These sources are highly likely to contain impurities making it unsuitable for human consumption. Hence, there is felt a need for a potable water purification system which can be easily transported, assembled and used when there is limited or no access to safe drinking water or limited access to electrical power source to purify raw water.

There have been attempts in the prior art to provide portable water purification systems, such as United States Patent Application 201 10303589 which discloses a water treatment system which includes at least a flocculation system, a chlorination system, and a bio-sand filter system. The patent application enables water which is taken from a water source, such as a lake, river, or well to be treated for consumption in rural or undeveloped areas. However, post bio-sand filtration process this patent application uses a chlorination process to disinfect water. Chlorine is known to be toxic to the human body and for health reasons the dissolved chlorine has to be removed before the water can be consumed thus increasing the filtration process and time.

Therefore there is a need for an apparatus or system for water purification to produce potable water:

• Which apparatus can be easily transported and assembled at a remote site;

· which minimizes clogging of filter pores during the filtration process due to accumulation of solid impurities;

• which reduces raw water turbidity; and

• which improves sterilization rate of bacteria and viruses thus producing safe drinking water.

SUMMARY OF INVENTION

The present invention relates to a method for purification of water, where raw water in a first tank is purified by adding and mixing with a pre-treatment chemical. Flocculants in the pre-treated water are allowed to settle and introduced to a pre-strainer unit; the pre-strained water is transferred into a second tank containing a bio-sand filter media for filtration; the filtered water is subjected to a UV disinfectant unit and the water now is discharged for consumption. Typically, the pre-treated water is distributed evenly over a pre- strainer unit where the pre-strainer includes a filter media with a pore size between 25μ to 200μ, preferably with a pore size of 50μ. Additionally, the filter media used is of polyethylene cloth.

Furthermore, the pre-treatment chemical and raw water is mixed for at least 15 minutes. The pre-treatment chemical used is preferably of alum or aluminum sulphate. The pre-strained water is transferred into a second tank by gravitational drop from the pre-strainer unit, the pre-strained water is subjected to a bio-sand filter media. The filtered water from the second tank now is introduced into the UV disinfectant unit from a perforated PVC pipe assembly positioned at the bottom of the bio-sand filter. A second aspect of the present invention relates to an apparatus for the method of purification of water comprising of:

- a frame support;

- at least two tanks mountable on the frame support;

- a pre-strainer unit to receive pre-treated water from a first tank;

- a disinfectant unit to kill living microorganisms;

- a mixing means including a stirrer and a blower device to mix pre- treatment chemical and the raw water in the first tank; wherein the frame support is made of rigid members assemblable to provide a collapsible frame support and is capable of holding two water tanks. Furthermore, the first tank is positioned above a second tank. In addition, the tanks are formed by bags consisting of water impermeable flexible sheet which is of canvas sheet. A chemical dosage means is mountable on top of the first tank, and it is capable of discharging pre-treatment chemical into the first tank.

Additionally, the disinfectant unit is a UV disinfectant unit to disinfect living microorganisms in the pre-treated water.

The disinfectant unit and the mixing means are powered by solar energy panel and a chargeable battery means. Alternatively, the disinfectant unit and the mixing means are powered using a permanent / fixed power supply.

Typically, the second tank includes bio-sand filter media comprising layers of sand, charcoal, fine and course gravel, and activated carbon each layer being separated by a permeable layer, wherein the permeable layer is at least one of a polyethylene sheet and a textile sheet.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The drawings constitute part of this specification and include an exemplary or preferred embodiment of the invention, which may be embodied in various forms. It should be understood, however, the disclosed preferred embodiments are merely exemplary of the invention. Therefore, the figures disclosed herein are not to be interpreted as limiting, but merely as the basis for the claim and for teaching one skilled in the art of the invention.

In the appended drawings:

FIGURE 1 is a perspective view of the framework to hold a first tank and a second tank in accordance with this invention;

FIGURE 2 is a front view of an assembled tank utilizing the framework illustrated in Figure 1 in accordance with this invention;

FIGURE 3 is a back view of an assembled tank shown in Figure 2 in accordance with this invention; FIGURE 4 is a perspective view of a first assembly of perforated PVC pipe to be placed in the first tank in accordance with this invention;

FIGURE 5 is a perspective view of second assembly of perforated PVC pipe to be placed in the second tank in accordance with this invention;

FIGURE 6 is a flow diagram of the method of purification of water in accordance with this invention;

FIGURE 7 is a diagrammatic see through perspective view of the purification apparatus minus the canvas sheet forming a tank in accordance with this invention; and FIGURE 8a and FIGURE 8b show a layout of a canvas sheet which is shaped to form a container for the raw water tank and the filtration tank before being fixed to the framework in accordance with this invention. DETAILED DESCRIPTION OF THE INVENTION

Detailed description of preferred embodiments of the present invention is disclosed herein. It should be understood, however, that the embodiments are merely exemplary of the present invention, which may be embodied in various forms. Therefore, the details disclosed herein are not to be interpreted as limiting, but merely as the basis for the claim and for teaching one skilled in the art of the invention. The numerical data or ranges used in the specification are not to be construed as limiting.

The present invention includes a multistep filtration process to generate water which is safe for human consumption. Referring to the accompanying drawings, FIGURE 1 discloses a perspective view, FIGURE 2 a front view and FIGURE 3 a rear view of a framework (13) to hold a first tank (10) and a second tank (12) in accordance with this invention.

In the first step of the method of purification of water as seen in FIGURE 6, raw water collected from a water source such as lake or pond water, rain water, ground water, and river water is filled in a first tank (10) referred to as raw water tank. Next, a pre-treatment chemical such as alum is added to a dripper system (1 1 ) to dispense the pre-treatment chemical into the first tank (10). The pre- treatment chemical is used to flocculate the raw water and can include aluminium sulphate (alum), polyaluminium chloride (PAC), ferrous sulphate, sodium aluminate, silicon derivates, lime or any chemical compound to facilitate flocculation of fresh water. To accelerate flocculation, the water is agitated using a mixer apparatus such as a stirrer and /or a blower commonly used to agitate or stir liquids contained in a receptacle. The mixer process is carried out for at least 15 minutes after which the treated water is allowed to settle for at least 30 to 90 minutes depending on the turbidity of water. Flocculated matter will settle at the bottom part of the first tank (10). Referring to FIGURE 7 which discloses a perspective view of the purification apparatus, the flocculated matter settled at the base of the tank is flushed out periodically by opening a discharge valve (15) attached to the basal region or base of the first tank (10). Pre-treated water from the first tank (10) is introduced into a second tank (12) referred to as the filtration tank via a first perforated pipe assembly (14) (see FIGURE 4). The pre-treated water in the upper part of the first tank (10) is introduced into the first perforated pipe assembly (14) via at least one valve controlled release pipe conduit (24) which is secured to the side wall of the raw water tank (10). The pre-treated water in the first perforated pipe assembly (14) flows down by gravitational force into a pre-strainer unit (16) placed in between the first tank (10) and the second tank (12). The first perforated pipe assembly (14) facilitates even distribution of water into the pre-strainer unit (16). The pre- strainer unit (16) includes a media to filter large solid particles. The filter media in the pre-strainer (16) is at least one sheet of polyethylene cloth with pores between 25μ to 200μ, preferably at best 50μ. The now strained water drops into the filtration tank (12) by gravitational force where it is filtered by a bio-sand filtration media (to be described later).

The filtered water flows into a second perforated pipe assembly (18) (see FIGURE 5) at the bottom of the filter media from where it flows into a valve controlled discharge pipe (36) to a UV disinfection unit (20) and is discharged into a collection receptacle (not illustrated). The discharged water is now purified and is in a potable state.

The preferred apparatus used in the method and other aspects of the method of purification of raw water will now be described in detail. The apparatus comprises a rigid rectangular framework (13) to receive and hold at least two water tanks. Preferably the rigid rectangular framework (13) comprises of a metal framework, more preferably aluminum framework with dimensions such as 1 .2 m (L) x 0.6 m (W) x 1 .5 m (H). Canvas sheet (28) preferably of food grade such as Detex tarpaulin (see FIGURE 8a) shaped into an open six sided bag is secured to the rigid rectangular framework (13) to form a container like a box-shape structure (see FIGURE 8b). The edges of the non-shaped canvas sheet (see FIGURE 8a) are secured together to form a water proof canvas bag to form a rectangular tank shaped container (30) (see FIGURE 8b) which is introduced into the upper portion as the first tank (10) and lower portion of the rigid rectangular framework (13) as the second tank (12). The upper edges of the canvas rectangular shaped container (30) are removably secured to the upper peripheral beams of the rigid rectangular framework (13). The base of the container rests on a first base plate (32) in the rigid framework. The base plate could be a wire-mesh tray or a plate with perforated holes or a solid plate. When assembled, at least one valve controlled release pipe (24) is secured to the side of the container. The release pipe (24) is in fluid connection with the first perforated pipe frame assembly (14).

A pre-strainer unit (16) is positionable below the first tank (10). The pre-strainer unit (16) places at least one sheet of filter material such as the polyethylene cloth with 25μ to 200μ micropores, preferably with 50μ micropores. The peripheral edges of the sheet are removably secured to the peripheral frame of the pre-strainer unit (16). A second tank (12) made of canvas sheet is secured to the second tank framework in the rigid framework. A second perforated PVC pipe assembly (18) is introduced onto the first base plate (32) of the second tank (12). Thereafter, a sand filter media is constructed. The sand filter media comprises of separate layers of sand, charcoal, fine and coarse gravel and activated carbon which are introduced onto the base of the second tank (12), above the second perforated PVC pipe assembly (18). Each media layer of sand, charcoal, gravel, activated carbon are separated by separate sheets of permeable material such as polyethylene cloth, textile cloth and material such as woven or non-woven plastics essentially to keep the different media separate and for ease of maintenance of the filter media. Water which has passed through the filter media enter the second perforated pipe assembly (10) and flow upward into a release pipe (36) whose end is secured to disinfector apparatus (20). A disinfector apparatus (20), preferably a UV light disinfector apparatus (20) is secured to the external side of the bottom region of the rigid framework (13). Water from the release pipe (36) is introduced into the UV light disinfector apparatus (20) at rate of at least 1 -20 liters/minute. The disinfected water where living microorganisms present in the water are killed by UV radiation is now discharged into a receptacle. The discharged water is purified and is potable. The present apparatus of the size described herein can yield up to 3,000 liter of potable water per day. The Table 1 below shows the parameters of the raw water being introduced into the first tank (10) and the parameters of the treated water as discharged from the UV disinfectant unit (20).

Date 29/7 31/7 6/8 16/8 24/8

Batch No. 1 2 1 2 1 1 1 2

PH R 5.5-9.0 6.4 6.4 6.3 6.2 6.2 6.2 6.2 6.2

W

T 6.5-9.0 6.6 6.7 6.8 6.7 6.8 6.7 6.9 7.0 w

Turbidity R <1000 31 20 60 45 50 30 280 250 (NTU) W

S Before 4.3 8.0 9.8 10.0 14.0 22.0 18.0 30.0 W p re- strainer

After 0.45 3.0 1 .6 2.0 1 .8 5.5 2.5 3.8 p re- strainer

T 5 0.71 0.58 0.61 0.65 0.48 1 .00 0.84 0.62 w

Color (TCU) R <100 12 10 12 13 15 12 22 20

W

T 15 <15 <15 <15 <15 <15 <15 <15 <15 w

Aluminium R 0.01 0.014 0.02 0.03 0.03 0.02 0.02 0.03 (mg/L) W 0 0 0 4 0 1 0

T 0.2 0.01 0.015 0.01 0.01 0.02 0.01 0.02 0.02 w 5 4 6 4 2 4 0

Ferum R 1 .0 1.10 1 .20 1 .10 1 .1 1 1 .42 0.12 1 .9 1 .87 (mg/L) W T 0.3 0.05 0.05 0.06 0.08 0.03 0.04 0.03 0.03 w

Manganese R 0.2 0.1 1 0.120 0.10 0.10 0.12 0.02 0.18 0.17 (mg/L) W 0 2 3 1 0 7 6

T 0.1 0.02 0.023 0.01 0.01 0.03 0.01 0.03 0.02 w 4 6 4 0 9 0 7

Ammonia R 1 .5 0.07 0.07 0.07 0.07 0.20 0.09 0.15 0.12 (mg/L) W

T 1 .5 0.04 0.02 0.02 0.02 0.03 0.02 0.03 0.03 w

Total T Absent ND ND ND ND ND ND ND ND coliform w

(cfu/100ml)

E.Coli T Absent ND ND ND ND ND ND ND ND (cfu/100ml) w

UV OK OK OK OK OK OK OK OK

Table 1 : Test results showing comparison between parameters of raw water and water treated by the present invention.

In addition, an exposed surface of the raw water tank (10) is covered by a solar panel (38). The solar panel (38) is connected to a modular power unit (40) and battery charging means to power the mixer apparatus and the disinfectant unit (20).

Claims

1 . A method for purification of water where raw water is subjected to flocculation and bio-sand filtration characterized in that the method comprises the steps of:

i. adding and mixing pre-treatment chemical into a first tank containing raw water to be purified;

ii. allowing flocculants in the pre-treated water in step (i) to settle; iii. pre-straining the settled water in step (ii);

iv. transferring the pre-strained water in step (iii) into a second tank containing at least one bio-sand filter media to be filter the water; v. introducing the filtered water in step (iv) to a UV disinfectant unit; and

vi. discharging the UV treated water in step (v).

2. A method as claimed in claim 1 , wherein the pre-treated water in step (i) is introduced over a filter media sheet where pore size is between 25μ to 200μ.

3. A method as claimed in claim 1 , wherein the pre-treatment chemical in step (i) and raw water is mixed for at least 15 minutes.

4. A method as claimed in claim 1 , wherein the pre-treatment chemical in step (i) is selected from a group consisting of aluminum sulphate (alum), poly aluminum chloride (PAC), ferrous sulphate, sodium aluminate, lime, and combinations thereof.

5. A method as claimed in claim 1 , wherein the pre-treatment chemical is aluminium suplhate (alum).

6. A method as claimed in claim 1 , wherein the pre-strained water in step (iv) is transferred into the second tank (12) by gravitational drop from a pre- strainer tray unit (16).

7. A method as claimed in claim 1 , wherein the filtered water in step (v) is introduced into the UV disinfectant unit (20) from a perforated PVC pipe assembly (18) positioned at the bottom of the bio-sand filter media.

8. An apparatus for a method of purification of water as claimed in claim 1 comprising of:

- a frame support (13);

- at least two tanks (10, 12) mountable on the frame support (13); - a pre-strainer unit (16) to receive pre-treated water from a first tank (10);

- at least a disinfectant unit (20) to kill living microorganisms; and

- a mixing means to mix pre-treatment chemical and the raw water in a first tank (10).

9. An apparatus as claimed in claim 8, wherein the frame support (13) is made of rigid members assemblage to provide a collapsible frame support and is capable of holding two water tanks (10, 12).

10. An apparatus as claimed in claim 8, wherein the first tank (10) is positionable above a second tank (12).

1 1 . An apparatus as claimed in claim 8, wherein the tanks (10, 12) are formed by bags consisting of water impermeable flexible sheets and supported by the frame support.

12. An apparatus as claimed in claim 1 1 , wherein the impermeable flexible sheet is of canvas sheet.

13. An apparatus as claimed in any of the claims 8 to 12, wherein a chemical dosage means (1 1 ) is mountable on top of the first tank, said chemical dosage means (1 1 ) is capable of discharging pre-treatment chemical into the first tank (10).

14. An apparatus as claimed in claim 8, wherein the disinfectant unit (20) is a UV disinfectant unit to disinfect living microorganism in the pre-treated water.

15. An apparatus as claimed in claim 8, wherein the disinfectant unit (20), and the mixing means are powered by solar energy panel (38) and a chargeable battery means (40).

16. An apparatus as claimed in claim 8, wherein the disinfectant unit (20) receives filtered water from the second tank (12) via a release pipe with flow rate of at least 1 -20 liters/minute.

17. An apparatus as claimed in claim 8, wherein a second tank (12) includes bio-sand filter media comprising layers of sand, charcoal, fine and course gravel, and activated carbon each layer being separated by a filter media separator sheet.

18. A method as claimed in claim 8, wherein the filter media separator sheet has a pore size of 50μ.

19. A method as claimed in claim 8, wherein the filter media separator sheet is a polyethylene cloth

20. Purified water produced by a method as claimed in claims 1 to 7.

21 . Purified water produced by an apparatus as claimed in claims 8 to 19.