KENYA BUREAU OF STANDARDS (KEBS)

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1 KENYA STANDARD Chemicals used for treatment of water intended for human consumption Part 4: Calcium hypochlorite Public Review Draft February 2007 KENYA BUREAU OF STANDARDS (KEBS) KEBS 2007 Second Edition 2007

2 TECHNICAL COMMITTEE REPRESENTATION The following organizations were represented on the technical committee. University of Nairobi Government Chemist Ministry of Water & Irrigation Consumer Information Network Nairobi Water & Sewerage Company Ltd K I R D I Orbit Chemical Industries Ltd Twiga Chemical Industries Ltd Kel Chemicals Ltd Medipharm E.A Ltd. REVISION OF KENYA STANDARDS In order to keep abreast of progress in industry, Kenya Standards shall be regularly reviewed. Suggestions for improvements to published standards, addressed to the Managing Director, Kenya Bureau of Standards are welcome. Kenya Bureau of Standards, 2007 Copyright. Users are reminded that by virtue of section 6 of the Copyright Act, Cap. 130 of the laws of Kenya, copyright subsists in all Kenya Standards and except as provided under section 7 of this Act, no Kenya Standard produced by Kenya Bureau of Standards may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in writing from the Managing Director. KENYA BUREAU OF STANDARDS (KEBS) Head Office: P.O. Box 54974, Nairobi , Tel.: ( ) , , Fax: ( ) info@kebs.org, Web: Coast Region Lake Region North Rift Region P.O. Box 99376, Mombasa P.O. Box 2949, Kisumu P.O. Box 2138, Nakuru Tel.: ( ) , /40 Tel.: ( ) 23549, Tel.: ( ) , Fax: ( ) Fax: ( ) Fax: ( ) kebs_msa@swiftmombasa.com kebs_ksm@swiftkisumu.com ii KEBS 2007 All Rights Reserved

3 Foreword This Kenya Standard has been prepared by the Technical Committee on Water Quality under the guidance of the Chemical Industry Standards Committee. The functions of calcium hypochlorite in water treatment are the removal of ammonium compounds, the oxidation of sulphides, the oxidation of iron (II) to iron (III) and as a disinfectant. It is used in aqueous solution, usually 1% (m/m) to 4 % (m/m) concentration. This product is mainly imported into the country and its quality has been varying very much, depending on the country of origin, thus the need for the standard. Calcium hypochlorite covered by this standard contains between per cent available chlorine. This material is unstable and can lose 3-10 per cent available chlorine in one year. It has fewer impurities of calcium chloride and calcium hydroxide than bleaching powder. The current edition of this standard incorporates requirements for bulk density, total content of mixed oxides and the description of the product. In the preparation of this Kenya Standard, reference was m ade to the following standards. SLS 759:1986 Specification for chlorinated lime (bleaching powder) and calcium hypochlorite SABS 295:1998 Specification for calcium hypochlorite KS : 1999 Specification for sodium hypochlorite solutions BS EN 900:2000 Chemicals used for treatment of water intended for human consumption Calcium hypochlorite. Acknowledgement is hereby made for assistance derived from these sources. KEBS 2007 All rights reserved iii

4 KENYA STANDARD Chemicals used for treatment of water intended for human consumption Part 4 Calcium hypochlorite 1 Scope This Kenya Standard specifies requirements and methods of test for calcium hypochlorite for treatment of water intended for human consumption. 2 Normative references This Kenya Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this Kenya Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. KS : 1999 Specification for bleaching agents - Part 1: Sodium hypochlorite solutions KS : 1998 Specification for bleaching agents - Part 3: Chlorinated lime bleaching powder for water treatment 3 Terminology The description for available chlorine given in Part 1 of this standard shall be applicable. 4 Application This standard applies to calcium hypochlorite granular powder or granules or tablets, used for water treatment. 5 Description 5.1 Chemical name Calcium hypochlorite 5.2 Synonym or common name None 5.3 Relative molecular mass Empirical formula Ca(ClO) Chemical formula Ca(ClO)2 5.5 CAS registry number Commercial form Calcium hypochlorite shall be white or yellowish-white granular powder, granules or tablets. 2 Chemical Abstracts Service Registry Number 2 KEBS 2007 All Rights Reserved

5 6 Requirements 6.1 Calcium hypochlorite granular powder or granules shall be free from lumps and shall not contain any dirt or other foreign material. Not more than 10 per cent of the powder shall pass a 100 µm sieve. 6.2 Calcium hypochlorite tablets shall be uniform in shape. The weight of the tablets shall not vary by more than 5 % average value stated in the label. Not more than 2 per cent of the tablets shall be broken. 6.3 After storage of the calcium hypochlorite in unopened container at a temperature not exceeding 25 o C and out of direct sunlight for a period of six months, it shall not have lost more than 10.0 per cent available chlorine on the basis of initial available chlorine when tested in accordance with Annex D of KS 1290 Part Calcium hypochlorite shall also comply with the requirements given in table 1. Table 1: Chemical requirements Sl. No. Characteristic Requirement Test method 1) Available chlorine,% (m/m), min. 65 KS 1290 Part 3 Annex A 2) Total content of aluminium 1.0 Annex A oxide ( Al 2 O 3 ), % (m/m), max. 3) Iron content, % (m/m), max Annex B 4) Moisture content, % (m/m), max. 5.5 KS 1290 Part 3 Annex B 5) Bulk density, g/cm 3,min. Granular material, 0.80 Annex C Tablets, Toxic substances Note For the purpose of this standard, toxic substances are those defined in the EU Directive 80/778/EEC of 15 July, 1980 (see [1]). The content of toxic substances shall conform to the requirements specified in Table 2. Table 2 Toxic substances Limit mg/kg of product Element Type 1 Type 2 Arsenic (As) max Cadmium (Cd) max 1 1 Chromium (Cr) max 6 10 Mercury (Hg) max Nickel (Ni) max 3 3 Lead (Pb) max 4 4 Antimony (Sb) max 5 5 Selenium (Se) max 1 1 Note Cyanide which does not exist in a strong oxidizing medium such as sodium dichloroisocyanurate, dihydrate is not a relevant toxic substance. Pesticides and polycyclic aromatic hydrocarbons are not by-products of the manufacturing process. KEBS 2007 All rights reserved 3

6 7 Sampling and compliance with the specification 2) 7.1 Sampling The following sampling procedures shall be applied in dete rmining whether a lot complies with the relevant requirements of the specification. The samples so drawn shall be deemed to represent the lot for the respective properties. From the lot take at random at least four containers and, after inspecting (see 8) each of them, use one container for testing for compliance with the requirement for shelf life (see 6.3). After thoroughly mixing the contents of each of the remaining containers, by taking an approximately equal quantity of material from each container and immediately placing it in one clean, dry, air-tight glass or plastics container, obtain enough material to provide a composite sample of total mass at least 1.5 kg. Clearly mark the name of the product, the manufacturer s name or trade mark, the batch identification and the date of sampling on the sample container. 7.2 Compliance with the specification The lot shall be deemed to comply with the requirements of the specification if, after inspection and testing of the samples taken in accordance with 7.1, no defective is found. 8 Inspection. Inspect the containers taken in accordance with 7.1 for com pliance with the requirements in clause 6. 9 Labelling Transportation Marking 9.1 Means of delivery Calcium hypochlorite shall be delivered in plastics -coated steel drums or polyethylene bottles which are not detrimental to the quality of the material during normal transportation and storage. In order that the purity of the product is not affected, the means of delivery shall not have been used previously for any different product or it shall have been specially cleaned and prepared before use. 9.2 Risk and safety labeling The following labelling requirements shall apply to calcium hypochlorite a) Symbols and indications of danger O: Oxidizing C: Corrosive b) Nature of special risks attributed to dangerous substances R 8: Contact with combustible material may cause fire; R 31: Contact with acids liberates toxic gas; R 34: Causes burns. c) Safety advice concerning dangerous substances S 2: Keep ou t of children S 26: Incase of contact with eyes, rinse immediately with plenty of water and seek medical advice; S43: Incase of fire, use air-independent respiratory equipment for fire fighting. 2) This section applies to the sampling for inspection and testing before acceptance or rejection of single lots (consignments) in case where no information about the implementation of quality control or testing during manufacture is available to help in assessing the quality of the lot. It is also used as the procedure for adjudicating in cases of dispute. 4 KEBS 2007 All Rights Reserved

7 9.3 Transportation regulations and labelling Calcium hypochlorite is listed as;? UN number for granular, calcium hypochlorite mixture, dry;? UN number 1748 for tablets, calcium hypochlorite, dry; Note: The above products contain less than 5.5 % (m/m) water and more than 39% (m/m) available chlorine. RID 4 : class 5.1 ADR 5 class 5.1 IMDG 6 class 5.1 IATA 7 class Marking The containers shall be securely closed and marked with the following information: (i) (ii) (iii) (iv) (v) (vi) Name and address of the manufacturer /supplier, and/or registered trade mark if any. Name of the product calcium hypochlorite Minimum percent by mass of available chlorine. For calcium hypochlorite tablets, the label shall show the number of tablets per unit weight. Code or batch number. Date of manufacture and use by date. (vii) Storing conditions indicating that the container should not be exposed to sunlight or any other heat source. (viii) (ix) (x) Net weight of the material in the container. Country of origin. Handling instructions. 3 United Nations Number 4 Regulations concerning carriage of Dangerous goods by rail 5 European Agreement concerning the international carriage of Dangerous goods by Road 6 International Maritime transport of Dangerous Goods 7 International Air Transport Association KEBS 2007 All rights reserved 5

8 Annex A Determination of total content of aluminium oxide A.1 Reagents a) Hydrochloric acid, of density at 15 o C = 1.16 g/cm 3 b) Nitric acid, of density at 20 o C = 1.42 g/cm 3 c) Ammonium hydroxide solution, of density at 20 o C = 0.90 g/cm 3 d) Hydrogen peroxide solution, approximately 10%(v/v) e) Ammonium chloride solution, 2 %(m/v) to which has been added sufficient ammonium hydroxide to make it just alkaline to methyl red. f) Hydrogen sulphide. A.2 Procedure a) Weigh, to the nearest g, approximately 10 g of the sample into a porcelain casserole. Add 50 ml of water and stir the mixture. Using a cover glass, cautiously add, a little at a time, 60 ml of the 10% hydrogen peroxide. Allow the reaction to subside and slowly add hydrochloric acid until the mixture is distinctly acid (approximately 30 ml will be required). When the reaction subsides, rinse the cover glass, catching the rinsings in the dish. b) Evaporate the solution to near dryness on a steam-bath and bake in an oven at approximately 120 o C until dry (about 1 h). Rem ove the casserole from the oven and allow it to cool. Cover with a watch-glass, carefully drench the residue with 30 ml of the hydrochloric acid, dilute with hot water to 150 ml, and digest on the steam -bath for 10 min. Rinse the cover glass, filter through a medium filter paper into a glass beaker, wash the residue thoroughly with a hot solution of dilute hydrochloric acid (1:9), complete the washing with hot water, and then discard the residue. c) Add 10 ml of dilute nitric acid (1:4) to the filtrate in the beaker and, after boiling for 1-2 min, almost completely neutralize with the ammonium hydroxide. Using methyl red as indicator, complete the neutralization with ammonium hydroxide, and add one drop in excess. Boil for 1-2 min and filter through a medium filter paper. Wash the residue six times with the hot 2% ammonium chloride solution. Retain the filtrate. Place the filter paper and its contents in the original beaker and macerate in 10 ml of the hydrochloric acid. Dilute with hot water to 150 ml, add three drops of the methyl red indicator, neutralize with ammonium hydroxide and add one or two drops in excess. Boil for 1-2 min and filter through a medium filter paper. Wash ten times with the hot 2% ammonium chloride solution, catching the fil trate in the beaker containing the filtrate from the first ammonium hydroxide precipitation. Retain the precipitate. d) Adjust the volume of the combined filtrate to about 200 ml, and transfer to a 300 ml conical flask. Add 2 ml of ammonium hydroxide, heat to boiling, remove the flame and pass hydrogen sulphide through the solution for 15 min. Stopper the flask and allow to stand for 1 h. If a precipitate is formed, wash with the 2% ammonium chloride solution and combine this precipitate with the precipitate retained in terms of (c) above. Ignite the combined precipitates at o C, cool, and weight as iron oxide, aluminium oxide and the oxides of heavy metals. Retain for the determination of the iron content. (Annex B) A.3 Calculation Calculate the total content of heavy metals plus aluminium oxide as follows: A Total content of mixed oxides of heavy metals plus aluminium oxide (AI ), %( m /m) =? 100 B 6 KEBS 2007 All Rights Reserved

9 Where A=mass of ignited precipitate, g B=mass of sample taken, g KEBS 2007 All rights reserved 7

10 Annex B Determination of iron content B.1 Reagents a) Stannous chloride solution. Dissolve 5 g of the crystallized salt in 10 ml of hot hydrochloric acid (density at 15 o C = 1.16 g/cm 3 ) and dilute to 100 ml with water. Keep the solution in a closed dropping bottle containing metallic tin. b) Phosphoric acid mixture. Add slowly, while stirring, 150 ml of orthophosphoric acid (density at 20 o C = 1.71 g/cm 3 ) and 150 ml of sulphuric acid (density at 20 o C = 1.84 g/cm 3 ) to 500 ml of water and dilute to 1l with water and mix. c) Diphenylamine indicator. Prepare a 0.3% aqueous solution of either the barium or the sodium salt of diphenylamine sulphonate. d) Standard potassium dichromate solution (c(k 2 Cr 2 O 7 ) = mol). Finely powder about 5 g of potassium dichromate and heat for min in an air oven at o C. Allow to cool in a desiccator. Accurately weigh out g of the dry potassium dichromate into a weighing bottle and quantitatively transfer to a 1l volumetric flask. Dissolve the salt in the flask in water and make up to the mark with water. Shake well. e) Hydrochloric acid of density at 15 o C = 1.16 g/cm 3 f) Potassium bisulphate g) Mercuric chloride solution. A saturated solution of mercuric chloride in distilled water. B.2 Procedure Add 2 g of potassium bisulphate to the crucible containing the ignited oxides (see A.2(d)). Slowly heat over a low flame and gradually increase the heat until the melt is cherry red and the oxides have dissolved. Allow the melt to cool and transfer it to a 250 ml beaker. Wash the crucible with hot water, receiving the water in the same beaker. Dilute to 50 ml, of the hydrochloric acid and heat to boiling. Next add the solution of stannous chloride, drop by drop, while stirring constantly, until the solution is decolourized, and then add one drop more. Cool in an ice-and-water bath, wash down the inside of the beaker with water and add (all at once) 10 ml of the mercuric chloride solution, previously cooled. Stir the mixture vigorously for 1 min, add 15 ml of the phosphoric acid mixture and three drops of the diphenylamine indicator. Dilute to about 150 ml with cold water, and titrate with the standard potassium dichromate solution. Take as the end point the stage at which a drop causes an intense deep blue colour that remains unchanged on the further addition of dichromate. B.3 Calculation Calculate the iron content as follows: Iron content, %( m /m) = VM? 33, 51 C Where V = volume of potassium dichromate solution required fo r titration, ml M = concentration of standard potassium dichromate solution, mol/l C = mass of sample taken, g (A.2) 8 KEBS 2007 All Rights Reserved

11 Annex C Determination of bulk density Weigh, to the nearest 0.1 g, approximately 40 g of sample (previously passed through a sieve with a stopper. Stopper the cylinder and pass a closely-fitting glass sleeve, of length about 75 mm, over it. Clamp the sleeve to a ringstand. Place a large rubber stopper under the cylinder, and so adjust the height of the sleeve that the measuring cylinder will be 100 mm above the rubber stopper when the base of the measuring cylinder touches the lower edge of the sleeve. Raise the measuring cylinder until it touches the sleeve, then release. Continue raising and dropping the measuring cylinder until 100 cycles have been completed. Read the volume of the test sample and calculate the bulk density in grams per milliliter. KEBS 2007 All rights reserved 9