IE86828B1

IE86828B1 - Rainwater purification system

Info

Publication number: IE86828B1
Application number: IE20140128A
Authority: IE
Inventors: Dawson Damien
Original assignee: Dawson Damien
Priority date: 2014-05-23
Filing date: 2014-05-23
Publication date: 2017-10-04
Also published as: IE20140128A1

Abstract

The invention provides for a multistage rainwater purification method to provide potable water comprising: a) collecting rainwater, b) a first flush filter, c) a first collection tank to regulate the flow of water, d) performing a first purification treatment running the water sequentially through a sequence of pre-filters and microbiological purification, e) collecting the water in a harvest tank, f) performing a second purification treatment including electropositive filtration, pH adjustment unit and microbiological purification involving UV disinfection or electropositive filtration, g) a supply tank prior to subsequent use wherein the water having been treated is recirculated through a UV disinfection unit or electropositive filtration unit at both the harvest tank and the supply tank to maintain water quality, and further by introducing an appropriate volume of chlorinated water from a public water supply to the treated water in the harvest tank. The invention also provides an apparatus to perform the method described.

Description

Field of invention The present invention relates to the purification of rainwater.

Background to the Invention Irish Patent No. IES85985 describes a three phase purification/sterilisation system. Following harvesting, rainwater is passed through a 5 micron pleated sediment filter and then feeds through an electro-positive filter which is the final phase of filtration. It then passes through an ultraviolet steriliser. The above invention describes the purification of rainwater to remove 99.9% of viruses and bacteria without the use of chemicals.

Rainwater always contains dissolved minerals, chemical pollutants and pathogenic organisms that it may have come in contact with when falling as rain and in the harvesting process. The purification system in IES85985 required to be extended to include additional purification processes and consequently this new invention uses an enhanced combination of technologies to provide potable water.

This invention effectively kills or removes bacteria/viruses and cysts from rainwater. It also removes suspended solids, natural organic matter, chemical pollutants, minerals and salts.

This invention provides harvested rainwater free from chemical and microbiological contaminants. Treated water in supply tanks will not become contaminated due to a unique and novel recirculation system. This invention also provides for the resolution of water quality problems which will occur where it is not practical or desirable to use UV disinfection in the recirculation system. In these instances where UV treatment may not be possible, electropositive filtration systems as described will provide water of the required quality.

The combination of coagulation, flocculation, sedimentation, multistep filtration including activated carbon filtration, sand filtration, pleated cartridge filtration, ozone treatment, UV disinfection, deionisation, reverse osmosis treatment, pH adjustment, deionisation and ultrafiltration provides both bacterial/viral free and contaminant free water suitable for 98% of all domestic, commercial and agricultural applications.

Summary of invention This invention of rainwater purification involves the removal of suspended particles, viruses/bacteria, parasites, cysts such as Giardia and Cryptosporidium, organic matter, dissolved metals and salts that may be present in rainwater.

According to the Invention there is provided a rainwater purification system, comprising the following: A A pre-treatment 1st flush system and fittings B A post-first flush collection tank, to govern the flow of water through the system C A coagulation, flocculation and sediment filtration treatment unit D A sand filter and 1-25 μ pleated cartridge filter E An activated carbon filtration unit F An ozonation treatment unit G A 1-25μ pleated cartridge filtration unit H A harvest tank, to collect rainwater from run-off area, typically the roof of the building in which the system is housed, after pretreatment by means of any or all of A-G Jl, J2, J3 Electropositive filtration units K A reverse osmosis treatment unit L A pH adjustment unit M A deionisation unit N An ultrafiltration unit P/Pl UV sterilizer units Q The supply tank in the building being supplied with treated potable water after pre-treatment by means of any or all of J-P R The main body of the building being supplied with treated potable water S, SI Recirculation loops, whereby treated water may be recirculated into the system to maintain its potability Brief Description of the Drawings The rainwater purification system according to this invention will be more clearly understood from the following detailed description of an embodiment thereof, given by way of example only, with reference to the accompanying Fig. 1 which illustrates a system of the invention.

Detailed Description of the Drawings Referring to Fig. 1, rainwater from a run-off area, typically the roof of the building to be supplied with potable water, enters the system at (A), a 1st flush system to remove leaves, debris and other large scale impurities before the filtration process. The water may then proceed to a first collection tank (B) which regulates the flow of water to be treated into the system.

The water then goes through coagulation, flocculation and sedimentation treatment (C). Coagulation is effected with the use of coagulating agents such as alum and/or polymers. Flocculation follows coagulation and involves a mixing technique which facilitates the aggregation of particles which become heavy and sink in a sedimentation process. This removes natural organic matter, colloids and some of the viruses and bacteria which may be present. A maximum flow pleated sediment filter removes the sediment before the water goes to the next treatment stage. The sediment filter cartridge and casing is washable and reusable. It is typically 1-25μ in grading, though other grades may be used in particular cases to suit the circumstances. It removes coarse particles and washed-in plant matter.

The water then proceeds through a number of filtration/treatment steps as follows: a sand filter and 1-25μ pleated cartridge filter step to remove algae and suspended material (D), activated carbon filtration (E) to remove contaminants, especially organic compounds, by chemical absorption, ozone treatment (F) to kill parasites, bacteria, fungi, viruses, algae while leaving no residual disinfectant in the treated water, and a second 1-25μ pleated cartridge filtration to remove particles of iron and manganese which may be introduced at the ozone treatment step.

This pre-treated water is then fed into a harvest tank (H), which stores the water before the second treatment regime. The harvest tank includes a recirculation loop (S), to maintain microbiological purity of the treated water by means of a UV sterilizer unit (P). The microbiological purity of the treated water can also be maintained by filtration through an electropositive filter (Jl) without the use of UV treatment.

Chlorinated water (generally from the public supply) is then added to the treated water in the harvesttank in the appropriate amount to help maintain quality and to insure against any prolonged period without rain.

The water in the harvest tank is suitable for supplying toilets or irrigation systems, but is not yet in a potable state. Thus, this water may be subjected to a second treatment to render it potable.

Water from the harvest tank is fed first to an electropositive filtration unit (J2) which removes 99.9% of all viruses and bacteria. Electropositive filters are known in the art to retain submicron particles effectively. The filters have high particulate capacity and resist clogging by small particles and are robust and fault tolerable. The filter cartridge used is rated ίμ absolute, and meets or exceeds the 99.9% efficiency requirement established by the Water Quality Association to reduce Cryptosporidium and Giardia cysts from drinking water.

The water then proceeds to a reverse osmosis system (K) to remove dissolved minerals and metals, metal salts, bacteria, viruses and parasites, a pH adjustment unit (L) to prevent corrosion in metal pipes in the building's plumbing and to improve potability. Rainwater, depending on harvesting location, can have a natural pH as low as 4.

An ion exchange treatment (M) then ameliorates water hardness following neutralisation and removes any toxic ions remaining in solution after the reverse osmosis treatment, after which an ultrafiltration membrane filter ( N ) removes any remaining viruses, bacteria and colloidal particles.

This treated water is then stored in the building's header tank, where a second recirculation loop (S') facilitates UV disinfection (P'), to maintain the microbiological purity of the treated water prior to use. The second recirculation loop also provides for electropositive filtration ( J3 ) in place of UV disinfection to maintain the microbial purity of the treated water prior to use.

Water supply to the header tank is delivered in such a manner as to wash down the exposed upper inner surface of the tank above the water level. This effectively avoids stagnant water droplets on the upper inner surface of the tank. Any water droplets not part of the recirculation system would be subject to microbial growth and lead to significant water contamination.

Variations in the above described embodiment may be envisaged, depending on the 5 circumstances, such as the initial state of the rainwater to be treated, the amount of recirculation prior to use, the volume of water required and the final use to which the treated water is put.

For instance, it may not always be necessary to employ ozone treatment, in which 10 case, the second pleated cartridge filter step (G) would also not be necessary.

Equally, if water is not required to be potable, the reverse osmosis step or others in the second phase of treatment may not be necessary.

Claims

1. A rainwater purification method to provide potable water comprising: a) collecting rainwater from a suitable run-off area, b) using a first flush filter to remove large scale impurities, c) collecting the water in a first collection tank to regulate the flow of water through the system, d) performing a first purification treatment running the water sequentially through a coagulation, flocculation and sediment filtration unit, a sand filter and pleated cartridge unit, an activated carbon filter unit, an ozone treatment unit, a second pleated cartridge filter unit and a first UV sterilizer unit, e) collecting the water in a harvest tank prior to further treatment, f) performing a second purification treatment running the harvested water sequentially through an electropositive filtration unit and a reverse osmosis unit, pH adjusting the water, deionising the pH adjusted water, and performing a second UV disinfection on the treated water, g) collecting the fully treated water in a supply tank prior to subsequent use, wherein the water having been treated is recirculated through a UV sterilizer unit at both the harvest tank and the supply tank to maintain water quality, and further by introducing an appropriate volume of chlorinated water from a public water supply to the treated water in the harvest tank

2. A rainwater purification method to provide potable water comprising: a) collecting rainwater from a suitable run-off area, b) using a first flush filter to remove large scale impurities, c) collecting the water in a first collection tank to regulate the flow of water through the system, d) performing a first purification treatment running the water sequentially through a coagulation, flocculation and sediment filtration unit, a sand filter and pleated cartridge unit, an activated carbon filter unit, an ozone treatment unit, a second pleated cartridge filter unit and a first electropositive filtration unit, e) collecting the water in a harvest tank prior to further treatment, f) performing a second purification treatment running the harvested water sequentially through a second electropositive filtration unit and a reverse osmosis unit, pH adjusting the water, deionising the pH adjusted water, and performing a third electropositive filtration on the treated water, g) collecting the fully treated water in a supply tank prior to subsequent use, wherein the water having been treated is recirculated through electropositive filtration units at both the harvest tank and the supply tank to maintain water quality, and further by introducing an appropriate volume of chlorinated water from a public water supply to the treated water in the harvest tank The method as in Claim 1 and Claim 2 wherein the coagulation, flocculation, sediment filtration and sand filtration steps are omitted. The method as in Claims 1 and Claim 3 wherein the second purification treatment and reverse osmosis treatment is omitted and an ultrafiltration step is added before the second UV treatment step. The method as claimed in claim 2 and Claim 3, wherein in the second purification treatment, the reverse osmosis treatment is omitted and an ultrafiltration step is added before the third electropositive filtration step. A rainwater purification method as described in Claims l,to 5 omitting the de-ionisation step. The rainwater purification method of any preceding claim wherein in the first purification treatment the ozone treatment and second pleated cartridge filtration treatments are omitted. The method of any preceding claim wherein 99.9% of coliforms, bacteria, cysts and Cryptosporidium are killed off/removed from the water to be treated. The method of any preceding claim wherein sediment and particulate matter down to 1μ in diameter is removed from the water to be treated. A method for purifying rainwater comprising: a) collecting rainwater from a suitable run-off area, b) using a first flush filter to remove large scale impurities, c) collecting the water in a first collection tank to regulate the flow of water through the system, d) running the water sequentially through a coagulation, flocculation and sediment filtration unit, a sand filter and pleated cartridge filtration unit, an activated carbon filter unit, an ozone treatment unit, a second pleated cartridge filter unit and a UV sterilizer unit, e) collecting the water in a harvest tank prior to further treatment, wherein the water having been treated is recirculated through a UV sterilizer unit at the harvest tank to maintain water quality, and further by introducing an appropriate amount of chlorinated water from a public water supply to the treated water in the harvest tank. 11 A method for purifying rainwater comprising: f) collecting rainwater from a suitable run-off area, g) using a first flush filter to remove large scale impurities, h) collecting the water in a first collection tank to regulate the flow of water through the system, i) running the water sequentially through a coagulation, flocculation and sediment filtration unit, a sand filter and pleated cartridge filtration unit, an activated carbon filter unit, an ozone treatment unit, a second pleated cartridge filter unit and an electropositive filtration unit, j) collecting the water in a harvest tank prior to further treatment, wherein the water having being treated is recirculated through an electropositive filtration unit at the harvest tank to maintain water quality by removing bacteria and further by introducing an appropriate amount of chlorinated water from a public water supply to the treated water in the harvest tank. 12 The rainwater purification method of claim 10 and 11 wherein the ozone treatment unit and second pleated cartridge filtration treatments are omitted. 13 A method according to any preceding claim wherein any activated carbon filter is rated at 1μ absolute. 14 An apparatus for purifying rainwater, the apparatus comprising: a) a first flush filter to remove large scale impurities, b) a first collection tank to regulate the flow of water through the system, c) a coagulation, flocculation and sediment filtration unit, d) a sand filter and pleated cartridge filtration unit e) an activated carbon filter unit, f) an ozone treatment unit, g) a 1-25μ pleated cartridge filtration unit h) a first UV sterilizer unit, i) a harvest tank for holding treated water prior to further treatment, j) an electropositive filtration unit k) a reverse osmosis unit, l) a pH adjustment unit m) a deioniser n) a second UV sterilizer unit, o) a supply tank to receive and store the treated water, p) a first recirculation loop in the harvest tank, to run any stored water through the first UV sterilizer unit to maintain water quality, q) a second recirculation loop to run the fully treated water through the second UV sterilizer unit to maintain water potability, and r) means for introducing chlorinated water from a public water supply to the treated water in the harvest tank. s) Means of recirculating water so that the exposed inner upper surface of the supply tank above the water level is washed with the recirculated water An apparatus for purifying rainwater, the apparatus comprising the following: a) a first flush filter to remove large scale impurities, b) a first collection tank to regulate the flow of water through the system, c) a coagulation, flocculation and sediment filtration unit, d) a sand and pleated cartridge filtration unit e) an activated carbon filter unit, f) an ozone treatment unit, g) a 1-25μ pleated cartridge filtration unit h) a first electropositive filtration unit, i) a harvest tank for holding treated water prior to further treatment, j) a second electropositive filtration unit k) a reverse osmosis unit, l) a pH adjustment unit m) a deioniser n) a third electropositive filtration unit, o) a header tank to receive and store the treated water, p) a first recirculation loop in the harvest tank, to run any stored water through the first electropositive filtration unit to maintain water quality, q) a second recirculation loop to run the fully treated water through the third electropositive filtration unit to maintain water potability, and r) means for introducing chlorinated water from a standard water supply to the treated water in the harvest tank. s) a means of recirculating water so that the exposed inner upper surface of the supply tank above the water level in the tank is washed with the recirculated water. The apparatus as claimed in claim 14 wherein the reverse osmosis treatment is omitted and an ultrafiltration treatment unit is added before the second UV treatment unit The apparatus as in claim 15 wherein the reverse osmosis treatment is omitted and an ultrafiltration unit is added before the third electropositive filtration unit. The apparatus as claimed in Claims 14 to 17 omitting the deioniser. The apparatus of any of claims 14 to 18 wherein the ozone treatment and second pleated cartridge filtration units are omitted. The apparatus of any of claims 14 to 19 which are capable of killing off of or removing 99.9% of coliforms, bacteria, cysts and Cryptosporidium from the water to be treated. The apparatus of any of claims 14 to 20 which are capable of removing sediment and particulate matter down to 1μ in diameter from the water to be treated. An apparatus for purifying rainwater comprising: a) a first flush filter to remove large scale impurities, b) a first collection tank to regulate the flow of water through the system, c) a coagulation, flocculation and sediment filtration unit, d) a sand filter and pleated cartridge filtration unit, e) an activated carbon filter unit, f) an ozone treatment unit, g) a pleated cartridge filtration unit h) a UV sterilizer unit, i) a harvest tank for holding treated water prior to use, j) a recirculation loop in the harvest tank, to run any stored water through the UV sterilizer unit to maintain water quality, k) means for introducing chlorinated water from a public water supply to the treated water in the harvest tank. An apparatus for purifying rainwater comprising: a) a first flush filter to remove large scale impurities, b) a first collection tank to regulate the flow of water through the system, c) a coagulation, flocculation and sediment filtration unit, d) a sand filter and pleated cartridge filtration unit, e) an activated carbon filter unit, f) an ozone treatment unit, g) a pleated cartridge filtration unit h) an electropositive filtration unit, i) a harvest tank for holding treated water prior to use, j) a recirculation loop in the harvest tank to run any stored water

3. 5 through the electropositive unit to maintain water quality. k) means for introducing chlorinated water from a standard water supply to the treated water in the harvest tank. 24 The apparatus of claims 22 and 23 wherein coagulation, flocculation,

4. 10 sediment filtration and sand filtration are omitted. 25 The apparatus of claims 22 to 24 wherein the ozone treatment and second pleated cartridge carbon filtration units are omitted.

5. 15 26 An apparatus according to any of claims 14 to 25 wherein any activated carbon filter is rated at 1μ absolute.