Research article Demonstration of acid and water recovery systems: Applicability and operational challenges in Indian metal finishing SMEs M. Balakrishnan a, * , R. Batra b , V.S. Batra a , G. Chandramouli a , D. Choudhury b, 1 , T. H € albig c , P. Ivashechkin c , J. Jain b, 2 , K. Mandava a , N. Mense a, 3 , V. Nehra b, 4 , F. R € ogener c, 5 , M. Sartor c , V. Singh b , M.R. Srinivasan d , P.K. Tewari a a The Energy and Resources Institute (TERI), Darbari Seth Block, IHC Complex, Lodhi Road, New Delhi, 110 003 India b STENUM Asia Sustainable Development Society, SFF 101, Palam Triangle, Palam Vihar, Gurgaon,122 017, India c Betriebsforschungsinstitut VDEh-Institut für angewandte Forschung GmbH (BFI), Sohnstraße 65, 40237 Düsseldorf, Germany d Asia Society for Social Improvement and Sustainable Transformation (ASSIST), No. 9, Desika Road, Mylapore, Chennai, Tamil Nadu, 600 004, India article info Article history: Received 17 April 2017 Received in revised form 17 March 2018 Accepted 21 March 2018 Available online 5 April 2018 Keywords: Resource recovery Diffusion dialysis Acid retardation Nanofiltration Metal finishing SMEs Technology demonstration abstract Diffusion dialysis, acid retardation and nanofiltration plants were acquired from Europe and demon- strated in several Indian metal finishing companies over a three year period. These companies are pri- marily small and medium enterprises (SMEs). Free acid recovery rate from spent pickling baths using diffusion dialysis and retardation was in the range of 78e86% and 30e70% respectively. With nano- filtration, 80% recovery rate of rinse water was obtained. The demonstrations created awareness among the metal finishing companies to reuse resources (acid/water) from the effluent streams. However, lack of efficient oil separators, reliable chemical analysis and trained personnel as well as high investment cost limit the application of these technologies. Local manufacturing, plant customization and centralized treatment are likely to encourage the uptake of such technologies in the Indian metal finishing sector. © 2018 Elsevier Ltd. All rights reserved. 1. Introduction Metal finishing is a surface treatment process that improves wear and tear resistance, imparts corrosion resistance and im- proves the aesthetics of metal parts. Various metal finishing tech- niques like electroplating, painting etc. are used to ensure quality and desired service life of metal components in consumer goods, engineering and construction industries. The electroplating in- dustry in India is composed primarily of small and medium en- terprises (SMEs) which are part of the supply chain for automobiles (cars, trucks), 2-wheelers (bicycles, scooters), engineering equip- ment and consumer goods. There are an estimated 12,000 organized units and around 300,000 small scale units in clusters across India (IITM, n.d). Due to the highly acidic waste streams and the hazardous sludge generated, electroplating is classified by Central Pollution Control Board (CPCB) as one of the major polluting industries (CPCB, n.d). Another key SME sector that em- ploys acid pickling is steel rolling. There are around 1800 small and medium sized steel rolling enterprises across India contributing to nearly 70% of long steel output (bars, sections, industrial products etc.) (Srinivas et al., 2013). As a first step in the metal finishing process, the component is cleaned to remove oil, scales and other surface impurities. Cleaning involves a series of operations including chemicals degreasing and * Corresponding author. E-mail address: malinib@teri.res.in (M. Balakrishnan). 1 Current address: National Productivity Council, E e 5, GIDC, Electronic Estate, Sector 26, Gandhinagar, Gujarat e 382 028, India. 2 Current address: Shree Cement Limited, Bangur Nagar, Andheri Deori, Beawar, Ajmer, Rajasthan e 305 901, India. 3 Current address: Frost and Sullivan India Pvt. Ltd., 2nd Floor, Focus Building, Near Kapil Complex, Baner Road, Pune e 411045, India. 4 Current address: National Productivity Council, Utpadakta Bhavan, 5e6 Institutional Area, Lodhi Road, New Delhi e 110 003, India. 5 Current address: Cologne University of Applied Sciences, Institute of Chemical Process Engineering and Plant Design; Betzdorfer Str. 2, 50679 Cologne, Germany. Contents lists available at ScienceDirect Journal of Environmental Management journal homepage: www.elsevier.com/locate/jenvman https://doi.org/10.1016/j.jenvman.2018.03.092 0301-4797/© 2018 Elsevier Ltd. All rights reserved. Journal of Environmental Management 217 (2018) 207e213