WINETECH Technical Yearbook 2019

CAROLYN HOWELL: ARC Infruitec-Nietvoorbij, Stellenbosch KEYWORDS: Treated winery wastewater, dairy and municipal wastewaters in New Zealand. JUNE 2019 MANAGEMENT AND RE-USE OF TREATED WINERY WASTEWATER (PART 2): DAIRY AND MUNICIPAL WASTEWATERS IN NEW ZEALAND

Carolyn went to New Zealand to participate in a technical tour focussing on the management and re-use of treated winery wastewater, with particular reference to wine grape irrigation. This article focuses on the visits to industries other than wineries to see how they manage their wastewater. She reports… The Western Cape is experiencing one of its worst droughts to date. Urban users are currently limited to 105 L of water per person per day, so water is a precious, scarce resource. Approximately three years of good rainfall is needed to recover from the drought. This implies that despite the winter rainfall of 2018, the region will still

feel the negative consequences for some time thereafter. Therefore, alternative sources of irrigation water for vineyards, e.g. using treated wastewaters, will become more important under the above-mentioned conditions or if climate change reduces long- term winter rainfall. THE GEOGRAPHY AND CLIMATE OF PALMERSTON NORTH Palmerston North is a city on the North Island of New Zealand. It is located on the eastern Manawatu Plains. Palmerston North is the country’s seventh largest city. The climate of Palmerston North is temperate with maximum daytime temperatures averaging 22°C in summer. Average daily temperature

PHOTO 1. The cow pad at Massey University dairy farm near Palmerston North.

is highest in February and lowest in July. Annual rainfall is approximately 918 mm, with rainfall occurring throughout the year. MASSEY UNIVERSITY DAIRY FARM NEAR PALMERSTON NORTH Cows come to the milking shed twice per day. Whilst they are waiting to be milked, they wait on the concrete pad (Photo 1). The concrete gets dirty from urine and

dung, and has to be washed regularly. The washing process generates approximately 70 L of effluent water per cow per day. It should be noted that the amount of dairy effluent water generated is highly variable and in New Zealand there are no government guidelines as to how much water can be used per cow per day. However, the wastewater produced from the milking cows is of a high quality. The wastewater is collected in deep,