Saturday, January 12, 2013

Water Pollution Reduction in the Textile Industry

Why was the project undertaken? 
During the 1970’s Hammarsdale was being developed as an industrial Hub to provide employment in KwaZulu. The textile industry in particular was being attracted to the area. The Department of Water Affairs and Forestry constructed the Hammarsdale Waste Water Treatment Works (HWWTW) to service the new industrial hub. There was poor environmental planning for the expanding Hammarsdale Hub. Because of this the quality of water in the Sterkpruit River was declining and the organic capacity of the HWWTW was at its limit. The effluent discharged by companies to the HWWTW was in certain circumstances highly corrosive and in one instance led to sewerage pipes being damaged and requiring replacement. Inlet screens designed to remove excessive materials were producing 25 cubic meters of waste per week that had to be disposed of at a low hazard waste disposal site. 

The high strength organic coloured effluents from the textile industries together with that arising from a chicken abattoir overloaded the works thus resulting in the colouration of the Sterkspruit River. This pollution was exacerbated since the treatment works was not designed to remove salts from the textile industries, which passed directly through the works into the River. Unfortunately the salt issue remains a problem but two companies, Gelvenor and Dano Textiles are investigating recycling their effluent and implementing cleaner production technologies to reduce the load. 

In 1982 Umgeni Water took over the HWWTW who assisted the University of Natal to deal with the issue of capacity by involving the Hammarsdale Industrial Conservancy in a campaign to persuade industry to reduce industrial waste loads. These efforts to minimise waste and encourage cleaner production resulted in energy, water and effluent treatment savings, but still there was little improvement in the quality of effluent delivered to HWWTW. At this stage Umgeni Water was applying an effluent tariff at a flat rate, which did not account for effluent strength. As a result there was no legal or financial incentive to reduce effluent loads. 

What Processes were undertaken? 

The incorporation of Hammarsdale and the nearby township of Mpumalanga into eThekwini Municipality and the Water Services Act of 1997 were significant factors leading to the reduction of effluent load. The Water Services Act stipulated that Municipalities were to become Water Services Authorities. Etekwini Municipality chose to own and operate Hammarsdale WWTW and having by-laws to support the collection of sewerage rates and to levy an additional charge for high strength effluent. 

The by-laws required that companies discharging to the Hammarsdale WWTW were permitted. A cooperative agreement between the Norwegian Pollution Control Authority and eThekwini Municipality led to the development of a five year integrated pollution control permit. The permit set targets for effluent colour. The permit also placed stress on waste minimisation / source control techniques which would reduce the salinity and therefore the electrical conductivity (a unit used for the measurement of the salt content of water) of discharged effluent. 

This approach to tariffs and pollution control permits was the innovative spark which led to the accelerated development of waste minimisation / source control techniques which could ensure that the effluent from the textile industry was at an acceptable standard. 

The development of the waste minimisation / source control technology, which was installed at Gelvenor, was funded by the European Union and the Water Research Commission. Gelvenor was identified since it was an ISO 14001 compliant company and, together with the potential trade effluent incentives was the most likely to succeed. This was an important decision, as the area needed a successful example to market the idea of cleaner production and better environmental controls. 

Project Description This project has two main components. The first is the five-year integrated pollution control permit, which sets targets for effluent colour, electrical conductivity and places stress on waste minimisation / source control techniques. 

The second component was the development of the waste minimisation / source control technology, which could benefit companies through reduced tariffs. In Gelvenor’s case this led to a reduction of chemicals, water and electricity in the production processes, and the discolouration of water was addressed through coagulation and settlement of the dyestuff in its effluent. 

What Positives have resulted from this project? 
Positives Hammarsdale Industrial township is now on the road to becoming more economically and environmentally sustainable. This has happened for various reasons. 

Firstly, the cost of utilities has been reduced to companies. Once cleaner production technology has been installed in the textile industry this can lead to reduced water use because consumption can be reduced if the treated effluent is recycled. For example, recycled water can be used in cooling towers and in air conditioning plants and this could lead to a savings of 40% on water. Further uses for the recycled water will be for dying, in toilets and for cooking. 

Because the quality of the effluent has improved, Gelvenor is being charged at a lower tariff, which can lead to a savings of R100, 000 per month. Using the same incentive scheme Rainbow Chickens also reduced its wasted load by 50%. This means that there is 25% less waste to treat at the works and therefore eThekwini, does not have to extend HWWTW with massive savings. The use of the cleaner production technology has released capacity at HWWTW, which can now be used to extend sanitation to approximately 8500 households in nearby Mpumalanga. 

The financial and environmental sustainability of certain companies has improved due to reduced water bills and effluent disposal costs yet improving environmental controls. These savings would more than finance the cleaner production technology at a rate of R4.5 million per annum. Gelvenor’s profit margin would increase after paying off the equipment cost over five years but Rainbow would recoup its costs in less than two. 

Because water effluent is cleaner the ecosystems of the Sterkspruit River and the Shongweni Dam will automatically improve. This will also improve the sustainability of farming in the immediate area and nature reserve surrounding Shongweni Dam will also have cleaner water input. 

The only negative is that it is difficult to address the salt issue since technology for salt removal from water is extremely expensive. Two companies however are investigating the salt removal and re-use of the water. 

What were the most important lessons learnt in this project? 

Co-operative governance really works. Because of the shortage of skills national and local government teamed up with international experts, local academics and parastatal organizations in order to address a common goal. No action by an individual organization would have succeeded on its own. Stakeholder collaboration need not be on a formal basis provided that the goal is clear, but does require a champion. 

Stakeholder collaboration can extend the use of the technology. 

-The University of KwaZulu-Natal is researching with Water Research Commission funding the re-use of saline effluents from textile mills. 

-Dano Textiles is investigating cutting-edge technology using nitrogen blankets in its dye-baths to reduce the quantity of sodium hydrosulphite and thus the salt content of its effluent. 

-Dye-bath effluent treatment trials have been launched using excess anaerobic sludge digestion capacity at Mpumulanga wastewater works. 

The cost of technology can be prohibitive. De-salination technology, despite major strides still remains a prohibitively expensive means of treating textile mill effluent. Farming still remains a problem because of salinity issues but the aesthetics and the organic contamination from Hammarsdale would improve.


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