WINETECH Technical Yearbook 2019

the third tank if necessary. The wastewater moves into the irrigation tank and is used for irrigation of pine trees that are located 3.8 km from the treatment plant. The application of these irrigations did not seem to result in salt accumulation in the soil. Two soil samples are required per year at this specific winery, one in the pre- and one in the post-vintage period. Solids are passed onto a belt filter press. The thickened sludge (Photo 5) can be used as a soil conditioner. At Cloudy Bay Winery, 5 000 tonnes of grapes are crushed per year. Sauvignon blanc, Pinot noir and Chardonnay are the cultivars focussed on. Their Sauvignon blanc is well known all around the world. The solids are removed from the wastewater and pass through three settling tanks (Photo 6). From the third settling tank, it is pumped into the main tank. Air is pumped into the main tank. The tank also has bacteria in it. The tank has a pH indicator so at any time one can ascertain what the wastewater pH is inside the main tank. Once per day, the water is pumped out and used for irrigation of woodlots planted with gum trees, indigenous vegetation and pastures. The local council visits the winery a couple of times per year. Water samples are taken regularly. Soil sampling is also done once per year and levels of elements in the soil have remained fairly constant. The winery also takes pro- active steps to minimise the amount of water used for the production of wine.

WINERIES VISITED IN THE MARLBOROUGH REGION The winery at Pernod-Ricard Winemakers has sluices for wastewater to run into, whereafter it is collected in a very big tank (Photo 3). The wastewater is disposed of by the local council. Wastewater quality is monitored by an on-site laboratory that measures total soluble solids (TSS) and BOD. The company is very pro- active in terms of sustainability and a natural wetland planted with New Zealand indigenous vegetation was visited. When Matua Wi ner y near B l enhe im planned to expand the capacity of their winery, they were required to reduce their environmental impact. This required an improved wastewater treatment system, which was built by Factor UTB. The system was completed in April 2016 and cost approximately R46 million. The winery wastewater is first treated at a balance tank with magnesium hydroxide [Mg(OH) 2 ]. Liquid Mg(OH) 2 buffers the pH quickly and the liquid is not as messy as powders. The water travels from the balance tank to the three wastewater tanks each having a capacity to contain 400 000 L of wastewater (Photo 4). Two of the tanks are used for wastewater treatment. The wastewater passes from the first tank to the second tank. The third tank is used for emergencies when too much wastewater is being produced to be contained in the first two tanks. The wastewater can also be further refined in

PHOTO 4. One of the 6 m high and 400 000 L capacity wastewater tanks at Matua Winery near Blenheim.

PHOTO 5. The thickened sludge from the wastewater treatment. The sludge has a spongy texture.