WINETECH Technical Yearbook 2019

does not undergo any further treatment. There are legal requirements with regard to discharge of wastewater to land, such as monitoring volumes automatically. Therefore, a resource consent has to be obtained from the regional council. In the resource consent there are general conditions, design standards and regulations concerning the management of environmental effects and monitoring. At Martinborough Vineyard, winery wastewater is used to irrigate windbreaks (Photo 1) rather than paddocks, because of the scarcity of land in the area. During vintage, the wastewater is almost irrigated directly to the windbreaks. In terms of water quality, the wastewater sodium adsorption ratio (SAR) and potassium adsorption ratio (PAR) are important. It should be noted that only one water quality sample is required during vintage. In the resource consent, the loading of nitrogen (N) and biological oxygen demand (BOD) is given in kg per hectare per year. Drip irrigation is used to irrigate the windbreaks and there have been no problems with clogging of drippers. Irrigation with wastewater may not continue if ponding occurs. Pa l l i ser Estate i s a sma l l wi ner y i n Martinborough where approximately 400 tonnes of grapes are crushed per year. Cultivars include Pinot noir, Riesling , Chardonnay, Sauvignon blanc and Pinot gris. Harvest is over by March or April. Most of the wastewater in the winery is generated by cleaning tanks. Storm water

is kept separate from the wastewater. The winery has stopped using NaOH as a cleaning agent. Instead, sodium bicarbonate, metasilicate and citric acid are used. In the case of pH adjustment, citric acid would probably be used to neutralise it. The winery also tries to reduce water used for cleaning by using blasts of hot water to clean the tanks. The wastewater system works on a float system. The wastewater is kept in the first chamber and the water in the second chamber is clear. Solids are removed once per year from the tank. Wastewater is irrigated almost immediately to an area of land near a windbreak. According to their resource consent, the outflow of wastewater is monitored automatically. Soil analyses indicate that there is no accumulation of salts associated with the wastewater irrigation. This is probably due to the relatively high rainfall in the area. Grape skins are also composted (Photo 2) at Palliser Estate in Martinborough. The grape skins are mixed with straw, cow manure and rock phosphate. The addition of the rock phosphate lifts the pH of the material and encourages earthworms to inhabit it. The mixture is composted for eight months. Thereafter it is used as a nutritional supplement in vineyards where growth vigour is poor or where young grapevines are growing. The compost pile in Photo 2 is covered and the material itself lies on a pad, which allows for the collection of the leachate.

PHOTO 2. The compost pad at Palliser Estate in Martinborough.

PHOTO 3. The wastewater collection tank at Pernod-Ricard Winemakers in Blenheim.