Water for people.pdf - WHO Thailand Digital Repository

P R O M O T I N G C L E A N E R I N D U S T R Y F O R E V E R Y O N E ’ S B E N E F I T / 2 4 1For these reasons, actions to use water efficiently and to eliminatecontaminating discharges must be based on precautionary actionspositively engaging industry in the sustainable development agenda.This requires the consideration of water governance issues, andimplies the development of consensus between community, industryand government actors, early on in planning and investmentprocesses. Within industry, a progressive package of environmentallysensitive improvements needs to be incorporated into productionmanagement and combined with the raising of technical capabilitiesat all levels.In high-income countries preventive methodologies have longbeen incorporated into the ‘toolkit’ of the production manager as allmanufacturing inputs and emissions have economic implications.This is less true of developing countries and countries withBox 9.4: Regional African leather and footwear industry schemeLeather-making is a significant source of income in mostAfrican countries but it is also a major cause of industrialpollution. Processes in tanneries are very water intensiveand tannery wastewater carries a large amount of spentchemicals as well as organic matter. Cleaner technologiesand better housekeeping and production practices canhelp reduce water use and chemical consumption as wellas wastewater contamination. Nonetheless, end-of-pipewater treatment is essential in containing the adverseenvironmental impact of the leather industry.UNIDO has been assisting Africa’s leather industriesover the last three decades and, since 1988, has providedassistance in pollution control to some thirty tanneries inEthiopia, Kenya, Malawi, Namibia, Sudan, Uganda, theUnited Republic of Tanzania, Zambia and Zimbabwe. Theseactivities confirm that a mix of waste management and ofcleaner technologies (such as high-exhaustion chrometanning, low sulphide dehairing, carbon dioxide deliming,wet-white processing) makes the tanning industry moreenvironmentally friendly; increases productivity; reducescosts; cuts water, energy and chemical consumption; andstrengthens the manufacturer’s image amongstconsumers. For example, using conventional technologies,up to one-third of the chrome used in tanning ends up inthe effluent; with high-exhaustion chrome tanningtechnology these effluent loads are reduced as 90 percentof the chrome is taken up in the leather. In consequence,less chrome is required.The overall benefits from these projects are expectedto be reduced water consumption and a significantreduction in the main components of the effluent load.Evidence from work to date indicates that chemical oxygendemand (COD) and BOD values can be reduced by up to60 percent while suspended solids, chromium and sulphidecan be reduced by more than 90 percent. The introductionof improved ‘house-keeping’ during production, includingbetter process controls, reduced overall water consumptionby more than 14 percent in an Ethiopian tannery.End-of-pipe water treatment represents a last butimportant mitigation strategy. Improving or installingtreatment facilities and capacity-building for monitoring ofthe effluent treatment process are important componentsof most projects.New ways of treating effluents and reducing solidwaste volumes have also been developed. At theZimbabwe Bata Shoe Company, a small-scale anaerobicdigester of tannery sludge has been successfully tested.The results confirmed the feasibility of installing a facilitycapable of handling 150 m 3 of sludge per day resulting inzero solid waste but generating biogas that could be usedas an energy source. The tannery wastewater is collectedin a small pond and from there gradually discharged into alarger pond where Spirulina algae thrive on what is leftof the effluent pollution load and make the pond anatural environment hospitable to fish, frogs and otheraquatic life.In Kenya, increasing human and industrial pollution toLake Nakuru over the past two decades resulted in asignificant deterioration in water quality and a sharpdecline in the flamingo population. Nakuru Tanners,situated in the immediate vicinity of Lake Nakuru NationalPark and a major exporter of wet-blue leather products,joined the pollution control efforts in the area and cleanerproduction and effluent treatments led to substantialreductions in polluter indicators. In 1998, flamingos beganto return to the lake in large numbers and most scientistsagree that some of the credit is due to the pollutioncontrol efforts made by the tannery.