Clean production approach in leather industry: Water and wastewater management

"Cleaner Production" is defined by the United Nations Environment Program (UNEP) as the continuous application of an integrated and preventive environmental strategy to processes, products and services in order to increase total efficiency and reduce risks on human and environment. One of the most important components of the European Union's environmental legislation in terms of industry is the "Integrated Pollution Prevention Control Directive (IPPC)", with its new name "Industrial Emissions Directive (IED)", published in 1996. The Directive brings a different approach to the prevention of industrial pollution and aims to concretize the principle of preventing pollutants at their source, which is based on the recipient environment characteristics and natural regeneration process as well as discharge standards. For this purpose, the Best Available Techniques (BAT) Reference Document were published for 33 sectors and the BAT Result Documents were published same sector and the required BATs were defined for reduction/prevention of emissions. The conductivity parameter which is detected in very high value in leather industry wastewaters and cannot be eliminated by conventional treatment processes, is one of the most important problems in the management of these wastewater. Salinity increases in the sources fed from the environments where treated wastewater is discharged and where irrigation water is used and the quality of the receiving environment is seriously deteriorated. In the management of these wastewater, it is important to prevent salinity at the source rather than removing salinity with advanced treatment methods. In the BAT Result Document published by the European Union in 2013 for leather processing sector, the use of mechanical shaking equipment for salinity removal in the management of wastewater or the appropriate one of the unsalted leather processing techniques are presented as mandatory BAT for the plant. In this study, water and wastewater management of leather industry discussed, MET practices and MET applicability rates were determined for leather processing plants operating in Turkey. In addition, two BAT alternatives selected in order to reduce the "Conductivity" parameter, which is one of the most important problems in the management of leather processing plant wastewater, to the acceptable values in order to improve the quality of the receiving environment, which is in the leather processing sector BAT lists and is one of the most important problems. As the first option, it was chosen to shake off the loose salt with mechanical shaking equipment before processing the salted leathers. However, since the conductivity values targeted in wastewater emission could not be achieved with this method alone, the installation of a Ultrafiltration (UF), Reverse Osmosis (RO) and Evaporation at the end of the wastewater treatment plant was also included in order to achieve the targeted criteria in the receiving environment. As the second option, curing of the leathers with cold preservation, which is a physical protection method, was chosen for the preservation of unsalted leathers. By comparing both BAT alternatives with Cross Media Effect and Cost Analysis, sectoral adaptability and contribution of BATs to environmental protection were also evaluated and the best BAT option was determined. As a result of both environmental factors and cost comparisons, cold preservation of leather without salting (2nd Method) has been determined as the BAT alternative to be preferred. In the study, the initial investment and operating costs were also calculated according to different scenarios in the case of applying the 2 BAT alternatives, which aim to solve the conductivity problem and make comparisons, taking into account the existing structure of the wastewater infrastructure managements and the facilities operating at varying capacities in our country and storing and preserving the skins for different periods of time. One of the most important criteria in deciding which of the benchmarked BAT options is the best BAT option is the evaluation of sectoral applicability. The 1st method is considered more applicable by the sector as the leather is preserved by curing with salt due to the long storage conditions that can extend from 6 months to 1 year in all leather processing facilities in our country. In solving this important problem, the long-term environmental and economic benefits of BAT applications should be highlighted by ensuring that the industry takes part in cleaner production activities. In addition, providing national incentive mechanisms will contribute positively to increasing the sectoral adaptability.