Over the past three decades, society has witnessed the birth, growth and maturation of regulation driven environmental (and occupational health and safety) protection programmes, and the related evolution of strategies, tactics and compliance programmes within the regulated community.
Modern consumer trends and legislation demands environmentally friendly and socially responsible practices, in turn leading globally to stricter legislation on environmental protection. The South African legal system emphasises the need for a structured process or strategy to prevent or minimise the environmental impact of a production process, or to treat any resulting effluent to acceptable levels as required by the appropriate legislation. Monitoring, inspection, auditing and policing structures have been introduced, to ensure long term compliance.
The wine industry is no exception in this regard, and any winery should be aware of the amount of water consumed, effluent generated and the pollution load of the wastewater. This information is not only required from a legal perspective, but is essential for the design of any treatment facility or waste minimisation program.
Cellars have a year round output of effluent, mostly as result of the various washing and cleaning operations associated with vinification. The bulk of the wastewater, generally more than 50%, is created during the harvest period. Due to the nature of vinification (essentially batch processing) the pollution load of the wastewater may exhibit significant variations, both on “short term” daily and seasonal “time frame”.
The Centre for Process Engineering at the University of Stellenbosch, in collaboration with the Agricultural Research Centre (Nietvoorbij) and the Institute for Agricultural Engineering, are currently involved in a project, sponsored by Winetech, to enable the development of a proposed Environmental Management Programme for the South African wine industry. Certain aspects of this programme involve the development of so-called “cause and effect” models by measuring the effect and impact that wine and spirit production has on the environment, as well as the development of consequent reaction models.
During the 2000 vintage season, sampling runs were conducted on 14 participating wine cellars, whilst 23 cellars were audited during 2001. On all the cellars, at least two sampling runs were conducted to establish a differentiation between the pre-, mid- and post-vintage data. Each sampling run consisted of two or more days of intensive 24 hour per day sampling. In cases where the discharge was in the form of a free flowing stream, samples were taken at 10 to 15 minute intervals and mixed to provide hourly composites. Where the effluent was temporarily stored in a tank or sump, the sampling frequency was extended according to the residence time in the vessel. Samples were also taken of the (periodic) outflow from these vessels prior to disposal or treatment. The samples were stored and analysed according to SABS standards. Where possible, flow rates were also monitored to take the effect of flow differentiation into consideration.
Besides characterising and measuring a process/system, there are several other benefits associated with an environmental audit:
- The identification of methods for the conservation or re-use of water.
- It provides the basis for the selection of appropriate treatment methods.
- The determination of resource degradation (pollution of water and soil on farm) and investment applications, e.g. land cultivation and other agriculture implementations.
- It provides valuable information concerning changes in reservoirs and other water sources.
- It provides public authorities with relevant information and assists them in establishing well-founded and attainable environmental regulations or directives.
Current environmental legislation requires the monitoring of several wastewater parameters. Since irrigation is the preferred method of disposal in the wine industry at present, the wastewater will be benchmarked (for the purpose of this article) against the legislative requirements for irrigation. These requirements are outlined in table 1.
Current Industry Position
During the audits, several parameters including Chemical Oxygen Demand (COD), Total Dissolved Solids (TDS), Suspended Solids (SS), pH and Electrical Conductivity (EC) were measured for the wastewater of the participating cellars. For illustrative purposes the COD will be used as a comparative parameter of the SA wine industry and the legislative requirements. COD is a parameter that gives an indication of the amount of oxygen needed to convert/degrade the organic content of a wastewater and is therefore indicative of pollution by organic substances.
The average results obtained from the environmental audits of 2000 and 2001, for the different participating cellars, are depicted in Tables 2 and 3. Table 2 displays some of the average results of the cellars that have taken part during 2000 and 2001, while Table 3 displays some of the results of the additional participants that joined the programme during 2001. To ensure anonymity of the participants the cellar names in the tables have been replaced with coding.
When the average COD values for 2000 and 2001, obtained from Table 2, are plotted on the same axis, some interesting comparisons are obtained as depicted in Figure 1.
As mentioned, one of the most obvious observations from Figure 1 is the large variation in contamination loading of wastewater from one cellar to the next. There is also a large variation in the water usage per ton of grapes processed and can vary from 2,5 – 10 litres of water used per litre of wine produced. This indicates a large variance in the production processes/practices utilised in the wine industry in general, as well as the absence of benchmarking and best practice guidelines in the industry. This is encouraging in a way that it predicts “room for improvement” by implementation of relatively simple process adaptations and principles. The Winetech programme addresses this problem by developing best practice guidelines for the industry, as well as benchmarking the environmental performance of the industry, by means of the environmental audits. Even though a large variation in the data exists from one cellar to the next, there is a good correlation of the data for 2000 and 2001 for the same cellar, which is indicative of well-planned and accurate sampling procedures.
It can be observed that few of the cellars comply with current legislation, which requires that wastewater production of less than 50m3 per day, that is utilised for irrigation, should contain COD loadings of less than 5 000 mg/l. Cellars producing less than 500m3 per day, and utilising it for irrigation, should decrease the COD loadings of the wastewater below the 400 mg/l level. It should also be mentioned that all of the cellars in Figure 1, with the exception of cellars D, produce more than 50m3 of wastewater per day, which places them into the “less than 400 mg/l COD” category. Besides the fact that most cellars do not comply with current legislation, what is more alarming is the fact that the average COD value for participants during 2001 was in the region of 9 000 mg/l. This indicates that a great deal still needs to be done to close the gap between current industry standards and legislative, international marketing and consumer requirements.
Even though this might indicate a relatively discouraging picture, some of the cellars such as B, F and I have shown significant improvements regarding the contamination loading of their wastewater, by implementing simple cleaner production practices, increasing general environmental awareness in their business, and by training and educating their employees in the importance of correct environmental strategies. It is perceived that the bulk of the SA wine industry’s environmental problems can be minimised by implementation of well-crafted cleaner production strategies, improved process control, better education and training, and implementation/integration of environmental management systems into general business practices.
Besides the observations superficially discussed in the previous paragraphs, the more prominent question as to “What needs to be done” has to be asked and addressed, if the South African wine industry wishes to ensure a sustainable and competitive future.
The first and most prominent aspect of increasing environmental performance in any company or industry is that it should be a priority, and that it should be managed like any other aspect of business. Environmental strategies should be integrated into all aspects of the business/production process.
When investigating companies both nationally and internationally, experience shows that appropriately crafted and executed environmental strategies can provide substantial and tangible financial benefits to a business. These benefits take the form of bottom line benefits, top line benefits, increased shareholder wealth and reduced investment risk.
The best approach to begin to implement these strategies:
- Integrate them completely in the business strategies and hold the line accountable,
- Set visible targets and report progress,
- Take continuous feedback from all constituencies. Look for non-traditional partnerships, for new ideas and learning,
- Build diversity of thought into your workforce and teams, and
- Confront your largest environmental or social challenge as a company or industry head on in an open and direct way; you might be surprised by who will come to your aid.
About the Authors:
S. Bezuidenhout (picture), N. Hayward, L. Lorenzen, N. Barnardt, M. Trerise
Centre for Process Engineering, University of Stellenbosch, P.O. Box 3501, Matieland, 7602 Tel. (021) 808-4485 . Fax. (021) 808-2059