Compositions – Water-softening or purifying or scale-inhibiting agents – Plant or organic material containing
Reexamination Certificate
2002-12-20
2004-12-07
Metzmaier, Daniel S. (Department: 1712)
Compositions
Water-softening or purifying or scale-inhibiting agents
Plant or organic material containing
C252S179000, C210S721000, C210S728000, C424S407000
Reexamination Certificate
active
06827874
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to compositions, methods and kits for use in the purification of contaminated drinking water for purposes of rendering it potable. The compositions and kits are especially designed for personal or domestic use in the batchwise purification and clarification of relatively small predetermined volumes of contaminated drinking water. The compositions and kits are also designed for personal or domestic use in the purification and nutrification of contaminated drinking water.
BACKGROUND TO THE INVENTION
There is a need for potable water in all areas of the world. In developed countries, water is purified and potable water is supplied on a large scale, typically by large national or multinational water management companies. This water is typically supplied directly to the consumers homes in a potable form. However, in some parts of the world, for example in some rural areas of developing countries, many people either do not have a direct water supply to their homes and only have access to a non-potable communal water supply such as a village well, or cannot be guaranteed that the water they do receive is potable. As a result, considerable numbers of people die each year as the direct result of drinking contaminated drinking water. Thus, there is a need for water purification kits and compositions that allow the consumer to purify their own water, which produces potable water in a fast and efficient manner.
Current water purification compositions available on the market to date, consist mainly of disinfectants, e.g. sources of chlorine and/or iodine, and do not adequately purify water. Water which is obtained after treatment by these water purification kits, may still comprise amounts of water impurities, e.g. heavy metal ions such as arsenic, which, when continually consumed for a prolonged period of time, may lead to health problems. Thus, there is a need to provide a water purification composition which removes water-impurities like heavy metal ions including arsenic and lead, more efficiently and effectively than current water purification kits.
It has now been found that water purification compositions based on certain combinations of inorganic coagulants and water-soluble or water-dispersible polymers remove greater amounts of water impurities, such as heavy metals, from water compared to current water purification compositions.
Also, current water purification compositions do not adequately remove, kill or inactive micro-organisms such as bacteria, viruses and cysts, which are present in the water. Thus, there remains a need to provide a water purification composition which does adequately remove, kill or inactive these micro-organisms.
It has now been found that when the composition of the present invention comprises a disinfecting agent, the composition removes, kills or inactivates a surprisingly larger amount of micro-organisms such as bacteria, viruses and cysts compared to water purification compositions known in the art.
In addition, the water which is to be purified by a water purification composition typically comprises a large amount of water-soluble organic content such as humic acid. With current water purification compositions, bleach, especially chlorine based bleach, can react with the water-soluble organic content and produce by-products in the water, including chlorine derivatives such as chloroacetic acid or chloroform, which are harmful to human and animal health. Thus, there is a need to provide water purification compositions, methods and kits which produce purified water comprising a low amount of disinfection by-products.
Another problem associated with the use of certain chlorine-based disinfectants such as calcium hypochlorite is that of product stability. In particular, it has been found that known compositions based on calcium hypochlorite can lose substantial disinfection efficacy under regular conditions of storage and use. Thus, there is a need for purification and disinfection compositions having improved storage stability.
After purification and disinfection of contaminated drinking water, there raises the further problem of maintaining the purity of the water until such time as it is required for drinking, whilst at the same time providing drinking water of satisfactory taste. Thus there is a need for compositions, methods and kits for purifying contaminated drinking water and which provides purified water having both longer life and improved taste attributes.
In addition to the need for purifying and clarifying contaminated drinking water, there is also a huge need in many parts of the world to improve standards of nutrition and health. The effective provision of both clean water and essential minerals and vitamins would clearly be of universal benefit but especially so in those parts of the world where potable water is in short supply. Thus there is a need for compositions, methods and kits for purifying and at the same time nutrifying contaminated drinking water.
SUMMARY OF THE INVENTION
The present invention relates to compositions, methods and kits for purifying and/or clarifying contaminated drinking water, as well as to compositions, methods and kits for purifying and nutrifying contaminated drinking water. In general terms, the compositions herein comprise at least a primary coagulant material and a so-called bridging flocculent material, the levels and ratios of coagulant to flocculent preferably falling within certain ranges. Highly preferred compositions also contain one or more of a coagulant aid, a microbiocidal disinfectant, a water-soluble alkali, a water-insoluble silicate (for example a clay, zeolite or mixture thereof), and a food additive or nutrient source.
According to a first aspect of the invention, there is provided a composition for purifying and clarifying contaminated drinking water and which comprises a primary coagulant, a bridging flocculent and a coagulant aid.
In preferred embodiments, the primary coagulant is selected from the group consisting of water-soluble, multivalent inorganic salts and mixtures thereof, for example, iron sulphate, iron chloride, aluminium chloride, aluminium sulphate, manganese sulphate, manganese chloride, copper sulphate, copper chloride, poly- variations thereof, and mixtures thereof. Generally, the compositions herein comprise from about 10% to about 99%, preferably from about 15% to about 50%, more preferably from about 25% to about 40% by weight of the primary coagulant.
The bridging flocculent on the other hand is preferably a high molecular weight water-soluble or water-dispersible polymer or mixture of polymers having a weight average molecular weight of at least about 2,000,000, more preferably at least about 5,000,000 and especially at least about 15,000,000. Bridging flocculents preferred for use herein are selected from the group consisting of water-soluble and water-dispersible anionic and nonionic polymers and mixtures thereof. Generally, the compositions herein comprise from about 0.1% to about 10%, preferably from about 0.2% to about 5%, more preferably from about 0.5% to about 3% by weight of the bridging flocculent
The term ‘coagulant aid’ herein refers to a water-soluble or water-dispersible polymer of lower molecular weight than that of the bridging flocculent and which aids the overall aggregation and flocculation process. The coagulant aid preferred for use herein is a low molecular weight, water-soluble or water-dispersible polymer which generally has a weight average molecular weight of less than about 1,500,000, preferably less than about 750,000 and especially less than about 300,000 and mixtures thereof. Generally the compositions herein comprise from about 0.1% to about 10%, preferably from about 0.5% to about 5%, more preferably from about 1% to about 4% by weight of the coagulant aid.
Although suitable coagulant aids include anionic polymeric hydrophilic colloids such as the carboxymethylcelluloses, highly preferred from the viewpoint of delivering excellent heavy metal, total soluble organic and cyst redu
Souter Philip Frank
Ure Colin
Alexander Richard
Chvey S. Robert
Metzmaier Daniel S.
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