Autonomic Water (Liquid) Purification System

Kazak State University, Kazakhstan
X-Master, Inc., New Hampshire, USA
Aliya Nurtaeva, Danko Priimak, Mikhail Nauryzbaev, Aytbala Tumanova, Valeri Svetov

Patent Application filed in Kazakhstan,
priority date 12/27/00, state registration # 2000/1374.1, patent approved on 09/24/01 by KazPatent

-self-sufficient, does not require special water pumping system, operable without any additional source of energy
-hermetic, prevents polluting during purification process
-possible to use not only for purification of water, but liquids in general as well: aggressive, volatile, poisonous
-based on standard filters, which are replaceable
-easy to manufacture

BACKGROUND OF THE INVENTION

This invention relates to apparatus in chemical engineering, particularly, to the methods of purifying water (liquids). It is designed to purify water from natural sources, e.g., to obtain drinking water in the absence of any energy sources for water pumping. The invention might be used also for purifying some volatile liquids.

Patents, pertinent to the present invention include Kentwood, US Patent No. 5,698,091, disclosing water purification system with radiation source used for automatic monitoring the process; Newman, US Patent No. 1,418,013, disclosing an improvement in water purification by treating same with an alkaline bleaching agent and a coagulant; Langelier, US Patent No. 1,465,173, disclosing a water purification method, involving treatment using a minimum dosage of coagulant in combination with an acid to yield ionic hydrogen and improved coagulation; Mallory, US Patent No. 2,138,349, disclosing a method and apparatus for aerating sewage using a series of internal rotating diffusing baffels; Riddick, US Patent No. 3,075,645, disclosing a water treatment system, whereby coagulant is added to the water, the mixture is aerated and then passed through a flocculation basin, then filtered; Horuguchi et al, US Patent No. 3,547,816, disclosing an aerating and filtering water purification system; Edwards, US Patent No. 3,772,188, disclosing a waste water treatment system using pressurized oxygen injection; Pradt, US Patent No.3,876,536, disclosing a high temperature and high pressure wet air oxidation process for treating waste water; and Reimann, US Patent No. 4,029,574, disclosing a process for aerating organically contaminated sewage with oxygen.

It is well known water purification system comprising open vessel with funnel and paper filter. The liquid to be purified is placed on the filter and passed through the filter under its own gravitation, being collected in another vessel.

The shortcomings of this system are the following:

-change in technical conditions of water purification while the decreasing of liquid volume (height of water column) in the funnel, namely, lowering of water pressure in the funnel in filtration process;
-multi-stage, intermittent process, requiring repeated procedure of filling out the funnel by liquid;
-low and uncontrolled rate of the process.

The above mentioned shortcomings are absent in the system of water purification using tap water supply as water pumping system, filter and open reservoir to collect water after purification, where the constant pressure on the filter is provided by the extent to which a faucet valve is opened. This system however cannot be used in the absence of tap water supply or any energy sources, necessary for water pumping. The other shortcoming arises from the fact that reservoir is open: possibility of interaction of purified water, collected in it, with surroundings (contamination, evaporation, chemical reactions with air components).

GOAL OF THE INVENTION

The goal of this invention is to provide self-sufficiency of water purification system, possibility of purification of aggressive, volatile, poisonous liquids, to maintain optimal purification conditions during the purification process, and to increase purification efficiency (side positive effect).SUMMARY OF THE INVENTION
The said goal is achieved by using hermetic reservoirs, the first one as water pumping apparatus and the second one as receiving reservoir, both filled by purifying liquid and compressed gas and connected with each other through pressure stabilizer. Hermetically sealed reservoirs allow to create in them an excess of gas pressure which provides feeding of purifying liquid onto the filter and facilitates collection of purified liquid. Pressure stabilizer maintains the constant difference in gas pressure in both reservoirs, the value being chosen on the basis of optimal conditions of purification process.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1



Fig.1 is a schematic representation of the preferred embodiment of water (liquid) purification system. The liquid to be purified (1) is being placed into hermetic reservoir (2) through branch pipe and open valve (4), the valve being closed thereafter. Using air pump (5), air is being compressed through back valve (6) in the reservoir (2) over purified liquid up to pressure P1, indicated my manometer (7) and then is pumped through pipe (8) onto differential pressure stabilizer DPS (9). DPS (9) allows air to pass from pipe (8) to pipe (10) if the difference between pressure P1 in pipe (8) and P2 in pipe (10) corresponds to the value P3, defined by technical parameters of pressure stabilizer. Further, the air is passing into hermetic reservoir (11), filling it and creating pressure P2 in it. Purifying liquid under constant pressure P3 is flowing from reservoir (2) to reservoir (11) through filter 12, having been purified. While liquid volume in reservoir (2) decreases, the volume of compressed air increases, which causes lowering of pressure P1. Simultaneously, increasing volume of purified liquid (13) in the reservoir (11) gives rise to decrease in air volume over liquid, that is to increase in pressure P2. Both these processes lead to lowering of pressure P3. If the pressure P3 drops lower than parametric value, DPS (9) allows air to pass from reservoir (11) through pipe (10), valve of DPS (9), branch pipe (14) into the atmosphere. Air pressure in reservoir (11) decreases, causing the difference in pressure in reservoirs (2) and (11) to increase, as the result of it, the given value of pressure P3 is reestablished

In order to collect purified water (13) from reservoir (11), the valve (15) is to be opened and water (liquid) under pressure P2 flows out from branch pipe (16). This is followed by decrease in pressure P2 and increase in pressure P3. Increasing of pressure P3 causes DPS (9) to operate. Air from reservoir (2) passes via valve of DPS (9), pipe (10) into reservoir (11), thus increasing pressure P2. Pressure P3 returns to the initial value.

In order to exclude failures in operation of system due to air leaking from reservoir (2) through filter (12) after purification of the total volume of unpurified liquid (1) or due to air leaking from reservoir (11) via valve (15), branch pipe (16) after the total volume of purified water has been collected, float valves (17) and (18) are used. When water (liquid) level reaches minimal acceptable value, float valves (17) and (18) get closed.

The function of differential pressure stabilizer and the influence of P1/P2 ration on pressure P3 may be illustrated on the following numerical example.

Let the pressure of air compressed in the first reservoir is equal P1=2 atm, and pressure stabilizer is set up at value P3=0.5 atm. Then, the pressure in the second reservoir will be P2=P1-P3=1.5 atm. Thus, the function of pressure stabilizer – to hold the constant difference in pressure P1 and P2. Therefore, P3=P1-P2=const=0.5 atm.

Let P1 is decreased by 0.01 atm, that is P1=2-0.01=1.99 and P2 is increased by 0.01 atm, that is P2=1.5+0.01=1.51,

Then P3=1.99-1.51=0.48 (instead of 0.5)

If the pressure P2 drops, P3 is increased, why?

Let P1=1.99; P2=1.51; P3=0.48. Let drop pressure P2 by 0.02 atm, then

P2=1.51-0.02=1.49 and P3=(1,99-1,49)=0,5 (instead of 0.48).

CLAIMS

1. An autonomic liquid purification system, comprising

-a water pumping device operated under the pressure;

-a filter;

-a reservoir for receiving and storing purified water, d i f f e r i n g in that the water pumping device operable under the pressure and the receiving reservoir are made as hermetic tanks, connected with each other by two channels: aerial, through the pressure stabilizer and hydraulic, through the filter.

2. The water purification system as in claim 1, d i f f e r i n g in that an input of hydraulic connection channel and input of a drain component are further provided with float valves.

Safety and controversies

Accidents have also been known to happen. In April, 2007, the water supply of Spencer, Massachusetts became contaminated with excess sodium hydroxide (lye) when its treatment equipment malfunctioned.^{[citation needed]}

Many municipalities have moved from free chlorine to chloramine as a disinfection agent. However, chloramine in some water systems, appears to be a corrosive agent. Chloramine can dissolve the "protective" film inside older service line, with the leaching of lead into residential spigots. This can result in harmful exposure to lead, with elevated blood levels of lead the outcome. Lead is a known neurotoxin.^[19]

[edit] Demineralized water

Distillation removes all minerals from water, and the membrane methods of reverse osmosis and nanofiltration remove most to all minerals. This results in demineralized water which is not considered ideal drinking water. The World Health Organization has investigated the health effects of demineralized water since 1980.^[20] Experiments in humans found that demineralized water increased diuresis and the elimination of electrolytes, with decreased blood serum potassium concentration. Magnesium, calcium, and other minerals in water can help to protect against nutritional deficiency. Demineralized water may also increase the risk from toxic metals because it more readily leaches materials from piping like lead and cadmium, which is prevented by dissolved minerals such as calcium and magnesium. Low-mineral water has been implicated in specific cases of lead poisoning in infants, when lead from pipes leached at especially high rates into the water. Recommendations for magnesium have been put at a minimum of 10 mg/L with 20–30 mg/L optimum; for calcium a 20 mg/L minimum and a 40–80 mg/L optimum, and a total water hardness (adding magnesium and calcium) of 2 to 4 mmol/L. At water hardness above 5 mmol/L, higher incidence of gallstones, kidney stones, urinary stones, arthrosis, and arthropathies have been observed.^[21] Additionally, desalination processes can increase the risk of bacterial contamination.^[21]

Manufacturers of home water distillers, of course, claim the opposite—that minerals in water are the cause of many diseases, and that most beneficial minerals come from food, not water.^[22][23][24] They quote the American Medical Association as saying "The body's need for minerals is largely met through foods, not drinking water."^[25] The WHO report agrees that "drinking water, with some rare exceptions, is not the major source of essential elements for humans" and is "not the major source of our calcium and magnesium intake", yet states that demineralized water is harmful anyway. "Additional evidence comes from animal experiments and clinical observations in several countries. Animals given zinc or magnesium dosed in their drinking water had a significantly higher concentration of these elements in the serum than animals given the same elements in much higher amounts with food and provided with low-mineral water to drink."

See Distilled_water#Criticism

Hydrogen production

For the small scale production of hydrogen, water purifiers are installed to prevent formation of minerals on the surface of the electrodes and to remove organics and chlorine from utility water. First, the water passes through a 20 micrometre interference (mesh or screen filter) filter to remove sand and dust particles, then a charcoal filter using activated carbon to remove organics and chlorine and finally a de-ionizing filter to remove metallic ions. Testing can be done before and after the filter to verify the proper removal of barium, calcium, potassium, magnesium, sodium and silica.

Another method that is used is reverse osmosis.

Other water purification techniques

Other popular methods for purifying water, especially for local private supplies are listed below. In some countries some of these methods are also used for large scale municipal supplies. Particularly important are distillation (de-salination of seawater) and reverse osmosis.

1. Boiling: Water is heated hot enough and long enough to inactivate or kill micro-organisms that normally live in water at room temperature. Near sea level, a vigorous rolling boil for at least one minute is sufficient. At high altitudes (greater than two kilometres or 5000 feet) three minutes is recommended.^[18] In areas where the water is "hard" (that is, containing significant dissolved calcium salts), boiling decomposes the bicarbonate ions, resulting in partial precipitation as calcium carbonate. This is the "fur" that builds up on kettle elements, etc., in hard water areas. With the exception of calcium, boiling does not remove solutes of higher boiling point than water and in fact increases their concentration (due to some water being lost as vapour). Boiling does not leave a residual disinfectant in the water. Therefore, water that has been boiled and then stored for any length of time may have acquired new pathogens.
2. Granular Activated Carbon filtering: a form of activated carbon with a high surface area, adsorbs many compounds including many toxic compounds. Water passing through activated carbon is commonly used in municipal regions with organic contamination, taste or odors. Many household water filters and fish tanks use activated carbon filters to further purify the water. Household filters for drinking water sometimes contain silver as metallic silver nanoparticle. if water is held in the carbon block for longer period, microorganisms can grow inside which results in fouling and contamination. Silver nanoparticles are excellent anti-bacterial material and they can decompose toxic halo-organic compounds such as pesticides into non-toxic organic products^{[citation needed]}.
3. Distillation involves boiling the water to produce water vapour. The vapour contacts a cool surface where it condenses as a liquid. Because the solutes are not normally vaporised, they remain in the boiling solution. Even distillation does not completely purify water, because of contaminants with similar boiling points and droplets of unvapourised liquid carried with the steam. However, 99.9% pure water can be obtained by distillation.
4. Reverse osmosis: Mechanical pressure is applied to an impure solution to force pure water through a semi-permeable membrane. Reverse osmosis is theoretically the most thorough method of large scale water purification available, although perfect semi-permeable membranes are difficult to create. Unless membranes are well-maintained, algae and other life forms can colonize the membranes.
5. The use of iron in removing arsenic from water. See Arsenic contamination of groundwater.
6. Direct contact membrane distillation (DCMD). Applicable to desalination. Heated seawater is passed along the surface of a hydrophobic polymer membrane. Evaporated water passes from the hot side through pores in the membrane into a stream of cold pure water on the other side. The difference in vapour pressure between the hot and cold side helps to push water molecules through.
7. Gas hydrate crystals centrifuge method. If carbon dioxide gas is mixed with contaminated water at high pressure and low temperature, gas hydrate crystals will contain only clean water. This is because the water molecules bind to the gas molecules at molecule level. The contaminated water is in liquid form. A centrifuge may be used to separate the crystals and the concentrated contaminated water.

Solar water disinfection

One low-cost method of disinfecting water that can often be implemented with locally available materials is solar disinfection (SODIS).^{[10][11][12][13]} Unlike methods that rely on firewood, it has low impact on the environment.

One recent study has found that the wild Salmonella which would reproduce quickly during subsequent dark storage of solar-disinfected water could be controlled by the addition of just 10 parts per million of hydrogen peroxide.^[14]

Various portable methods of disinfection

Available for disinfection in emergencies or in remote locations. Disinfection is the primary goal, since aesthetic considerations such as taste, odour, appearance, and trace chemical contamination do not affect the short-term safety of drinking water.

Hydrogen peroxide disinfection

Works in a similar way to ozone. Activators such as formic acid are often added to increase the efficacy of disinfection. It has the disadvantages that it is slow-working, phytotoxic in high dosage, and decreases the pH of the water it purifies.