1. SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION 1 www.ihtpk.com SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION Chemical Conservation Dr. Naeem-uz-Zaman eeengrs@yahoo.com

2. SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION 2 www.ihtpk.com Presentation Sequence Chemical Conservation in Processing Industries Chemical Conservation Technique – Material Auditing – Bench Marking – Process Control Case of Textile Processing Industries Case of Leather Processing Industries

3. SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION 3 www.ihtpk.com Chemical Process Industries Sugar Industry and Distillery Pesticides Fertilizers Drug and Pharmaceuticals Refinery Pulp and Paper Tannery Textile Industry Rubber and Plastics Dye and Dye Intermediates Paints and Synthetic Resins Food Processing and Allied Industries

4. SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION 4 www.ihtpk.com Chemical conservation is very subjective and specific to a industry. However there are some general rules which can help in reducing the chemical consumption.

5. SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION 5 www.ihtpk.com Chemical Conservation: How Material Auditing Bench Marking Process Control Use of Efficient Technology

6. SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION 6 www.ihtpk.com Reduction in Chemical Consumption Keeping a very close record of chemicals purchased and used. There are cases where only annual consumption is monitored. In this system, it is very difficult to know as to how much chemical was wasted or pilferage. By relating the chemical consumption with daily production, a close check can be maintained on actual consumption of the product. Any deviation from the standard will immediately reflect the inefficient usage of chemicals. It is economical to purchase chemicals in bulk. However while using small quantities from large containers spillages are evitable. Particularly when inexperienced persons are handling the chemicals. In certain cases, bulk chemicals packed into daily consumption packets at the warehouse. In this way a specific quantity in a packet is delivered to the production people and if they ask for additional chemical, the reason must be identified.

7. SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION 7 www.ihtpk.com Training of Production Personal Production people must be educated in the use of chemicals. They must know the exact quantities required per batch or per unit of production. They should also know the effect of using less or more than the specified quantities. In this way not only the consumption of chemicals is controlled but the quality of the end product is also controlled.

8. SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION 8 www.ihtpk.com Process Control Each production method requires specific steps to get a uniform quality product at most economical cost. If any deviation is made form standard, the use of raw material and chemicals may increase. In tanning industry, Chrome tanning is sensitive to pH which is sensitive to temperature. As the pH varies with temperature, it is very essential to maintain the temperature of tanning medium at optimum conditions. Variation in temperature will result in change in pH requiring more than desired quantity of chemicals to obtain the same desired results.

9. SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION 9 www.ihtpk.com ECO Friendly Chemicals Initially the production method were developed to get a product at the most economical price and no effort was made regarding it environmental effects. Solid waste generated was land filled, liquid waste was thrown into natural water steams or allowed to accumulate in ponds and gaseous waste was vented to the atmosphere. As the awareness regarding the environmental effects of waste generated became apparent, industry started making effort to develop eco friendly methods of production.

10. SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION 10 www.ihtpk.com ECO Friendly Chemicals Coatings such as paints and plastics were dissolved into organic solvents (VOC) some of which are known carcinogenic such as Benzene, Toluene etc. Considerable efforts have been made in this industry where water based solvents and solvent free coatings (powder Coating) have been developed.

11. SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION 11 www.ihtpk.com SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION Chemical Recovery Case of Textile Processing

12. SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION 12 www.ihtpk.com Size Recovery Size is applied on yarn to prepare it for weaving purposes. The basic purpose of size is to give stiffness to the yarn so that it can be weaved easily. Sized clothes is then sent to textile processing where first step is to remove the size and prepare the cloth for dying and printing purposes. Starch are natural or synthetic materials used for sizing purposes. Being water soluble organic compounds, the size adds to the BOD of the effluent. Methods have been developed to recover and reuse the sizing material. It has two advantages: – Recovered size is much cheaper than fresh size. – Its recovery BOD/COD load of the effluent

13. SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION 13 www.ihtpk.com Caustic Recovery Caustic soda is extensively used in textile processing for mercerizing purposes. After treating with caustic the cloth is washed to free it from even trace from caustic so that it can be prepared for dying and printing. Caustic being an expensive chemical, it is economically possible to recover it. It is essential that the waste caustic solution has high concentration of Caustic upto 4% which is achieved by counter current washing. Dilute caustic solution is filtered, de-colorized and concentrated by evaporation.

14. SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION 14 www.ihtpk.com Dye Recovery – Cloth generally absorbs a part of the dye present in dying medium and a certain fraction of dye remains in water. – Dye recovery is a new and complex method as very dilute solutions with specific chemical compounds are to be handled. – Besides evaporation, RO membranes have been developed to recover specific dyes.

15. SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION 15 www.ihtpk.com SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION Chemical Recovery Case of Leather Processing Industries

16. SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION 16 www.ihtpk.com Salt Recovery Raw Hides are preserved by salting For tanning purposes salt must be removed from the hides. Though salt is very cheap, if thrown into effluent it adds to sodium and Cl pollution. Dry salt is recovered by – Shaking of the hides – Tumbling of the hides – Brushing of the hides. This recovered salt can be reused after treatment. After dry removal of the salt, hides are soaked in water to dissolve the salts sticking with the hides. This salt solution can also be reused after filtration and disinfection. Thus practically all the salt present in hides can be recovered.

17. SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION 17 www.ihtpk.com Lime Recovery De-Salted hides are treated with milk of lime Ca(OH)2 to soften them. The lime slurry can be recovered and reused after filtration. Limed hides are treated with Sodium Sulfide to remove hair. This sodium sulfide lime solution can also be recycled after filtration and treatment. Hair removed in this process can be used for felt making.

18. SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION 18 www.ihtpk.com Chrome Recovery A 4 to 6 percent solution of basic chromium sulfate at pH 3 is used for chrome tanning. Generally hides absorb up to 70 percent of this chemical and 30 percent is left is solution. Some chemicals have been developed where more than 70 percent chrome is absorbed by hides. However a fraction of chemical still remains in solution.

19. Chrome Recovery: Options Fresh chromium chemical may be added to this waste solution and it may be recycled two to three times before it becomes so contaminated that it must be drained. Precipitation by magnesium hydro oxide: by adding Mg (OH)2 to the waste chrome solution its chrome contents are precipitated. On settling the chromium hydro oxide occupies nearly 25% of the original volume. After decanting the supernatant liquid, the chromium hydro oxide is re-dissolved in sulfuric acid and recycled. The most efficient method is to add sodium hydro oxide to waste chrome solution where chromium hydro oxide is precipitated in the form of gelatinous precipitate which does not settle easily. This precipitate is de-watered by using filter press. The precipitate can also be washed while it is in the filter press. The recovered filter cake contains 25-30% solids and is free form water soluble impurities. On dissolving the sulfuric acid, a very concentrated solution (500g/l) of basic chromium sulfate is obtained. This can be used by blending it with fresh chromium sulfate and the results obtained are similar to fresh chromium sulfate treatment.

20. SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION 20 www.ihtpk.com SCI-Pak Sustainable and Cleaner production in the manufacturing industries of Pakistan FUNDED BY THE EUROPEAN COMMISSION Thank You