INTERNATIONAL
CLEANER
PRODUCTION
INFORMATION
CLEARINGHOUSE
INTERNATIONAL
CLEANER
PRODUCTION
INFORMATION
CLEARINGHOUSE
CASE STUDY #23 1. Headline: DESIRE: Cleaner Production in small-scale industries: Reducing waste in paper manufacture 2. Background: In March 1993, the Energy and Environment Branch of the United Nations Industrial Development Organization (UNIDO), in close cooperation with the National Productivity Council (NPC) and several other industrial organizations in India, initiated a cleaner production demonstration project targeting small scale industries (SSIs) in India. The project DESIRE (Demonstration in Small Industries for Reducing wastE) began in March 1993. Its objectives included: - the demonstration of cleaner production opportunities and benefits to small-scale industries in India - the development of a systematic method for cleaner production - the identification of obstacles and incentives for cleaner production - the formulation of cleaner production policies. Three sectors: - agro-based pulp and paper production - textile dyeing and printing - pesticides formulation were targeted for demonstration projects, as they are sources of significant pollution and are primarily made up of SSIs. Four to six companies in each of the sectors have participated as demonstration units in the project. Although final results are awaited on DESIRE, preliminary data from the participating companies show economic and environmental improvements. M/s Ashoka Pulp and Paper Mills participated in the DESIRE project with the twin objectives of: - reducing production costs, and - bringing about cost-effective compliance with environmental regulations. Local pressure to improve environmental performance and conserve water were other reasons behind the decision to actively pursue waste minimization program was launched with assistance from the National Productivity Council. Agro-residue based pulp and paper mills generally use chemical pulping process based on sodium hydroxide. During digestion, steam dissolves the undesirable portion of raw material. Waste paper or purchased long fibre pulp is added to provide the required percentage of long fibre in the furnish. Hydropulping is employed for pulping the waste paper. After cooking, the digested pulp, the spent cooking (black) liquor, and the condensed steam are discharged directly into a washer. The pulp is washed to remove the black liquor, and is then passed through a centricleaner, where thickeners and refiners remove inerts and undigested material. The cleaned pulp is conditioned, diluted with recycled water and fed to the paper machine. The diluted pulp forms a web on the endless wire mesh and the excess water is drained out by gravity and vacuum. Further dewatering is carried out by pressing between two rolls and felts and by steam dryers. Finally, the dried paper is cut and dispatched. Excessive paper breakage often occurred during the final stage of the paper making process. The clauses included: - pressure fluctuations at the edge cutting nozzles due to variations in levels in the water storage tank - variations in pulp consistency - excessive fines in pulp due to inefficient dedusting of raw material - use of single felts, resulting in a high shear force. The first two items were due to improper process control, and the rest due to obsolete process technology. M/s Ashoka Pulp and Paper Mills is an agro-residue based pulp and paper mill producing unbleached semi Kraft paper. The average production of the mill is 36 tons per day. 3. Cleaner Production Principle: Process modification, new technology. 4. Description of Cleaner Production Application: The problems were solved by a combination of process modification, equipment modification, and new technology. A separate water storage tank and pump were installed to ensure a constant water level, and thus constant watr pressure at the edge cutting nozzles. An additional smaller water pipeline was installed at the dilution point, along with a consistency indicator for precise consistency control at the inlet of the paper machine. New technology, comprising mechanical dedusting of raw material, was adopted to reduce fines in the pulp. The existing ebonites press rolls were replaced by mild steel rolls, which have a smoother surface, and the single felt system was replaced by a double felt system. 5. Economics: Item Annual savings (US$) Paper making capacity 37 290 Effluent treatment plant (0.8 TPD COD reduction) 8 910 Kerosene consumption 35 640 Fibre loss 52 140 Total 133 980 US $ Capital investment 25 000 Operating costs/year 15 000 Net savings/year 118 000 Payback period <3 months 6. Advantages: Benefits gained from the implementation of cleaner production techniques included: - reduced paper breakage, reducing fibre loss by 0.4-0.5 t/day and reducing production capacity loss by 3.6-5 t/day - an increase in wire life - reduced maintenance - reduced stress on workers Reductions per day Pulp reprocessing 3-4 tons Fibre loss in wastewater 0.5 tons Pollution load COD 800 kg TSS 600 kg Kerosene consumption 540 liters 7. Constraints: N/A 8. Contacts:Mr S.P Chandak, Director Mr Rajeev Wadhwa, Deputy Director Mr Shisher Kumra, Assistant Director National Productivity Council 5-6 Institutional Area Lodi Road New Delhi 110 003 India Tel: +91 11 461 1243 Fax: +91 11 461 5002 Mr Shivkumar Ashoka Pulp and Paper Mills Jhawar Najar, Loni Road New Delhi India Tel: +91 11 22 83660 Fax: +91 11 22 96670 9. Keywords:India, pulp and paper, process modification, new technology, COD, fiber, DESIRE, agro-residue 10. Reviewer comments: This case study was originally published in the UNEP IE document "Cleaner Production Worldwide", Volume II. In the process of preparing the document the case study underwent a technical review.