New Zealand has cultivated an image as a country of pristine lakes, rivers, and fjords, but the image has suffered in recent years as the country’s dairy industry has experienced explosive growth. Dairy has long been a part of New Zealand’s heritage, according to the Dairy Companies Association of New Zealand. The country has in short order become one of the world’s top suppliers of dairy products, with exports of $9 billion to Asia, the Mideast, and the United States. Global success, however, may have come at an environmental cost.
According to an article in The Economist, government data from as far back as 2013 has suggested that 60% of New Zealand’s lakes were unsafe for swimming. A government study also found that the tap water of 900,000 New Zealanders, approximately 20% of the population, is unsafe for drinking.
One sobering confirmation of the figures was a major 2016 outbreak of waterborne Campylobacter that struck more than 5,000 inhabitants of the Hawkes Bay suburb of Havelock North, hospitalizing dozens and putting some in intensive care. Three lost their lives.
In the aftermath, some major projects are running into resistance from a concerned public. One casualty is the proposed $240 million Ruataniwha Dam project in Hawkes Bay, which would have been New Zealand’s largest irrigation project yet to create new cattle grazing land. In an environment of increasing public concern over grazing land runoff, New Zealand’s Supreme Court invalidated an essential land swap, allowing the Hawke’s Bay Regional Council to shelve the project. The massive project is now considered “dead.”
High-Tech and Low-Tech Remediation
Researchers are confident that new water quality restrictions under consideration would help New Zealand’s surface water in the long term, and at some cost to industry. One approach embraced by some in the dairy industry is the use of waste-to-energy solutions.
Anaerobic digestion can be used to process manure and simultaneously produce biogas to power farm operations, cutting energy costs, leaving farmers with usable fertilizer as a byproduct, and shrinking the operation’s carbon footprint. Other dairy byproducts can also be processed. In Italy, for instance, Fluence technology allowed a dairy processing facility to generate biogas from excess whey.
Waste-to-energy solutions are most feasible with a concentrated source of material for fuel, such as at slaughterhouses or feedlots. In open fields, runoff can be diverted through relatively low-tech trench bioreactors to protect waterways. The reactors convert nitrates into nitrogen gas, the main component of the air we breathe.
Other simple solutions can be seen in the American Midwest, where grass filter strips have been used at the edge of agricultural fields to remove nitrates, and in a University of California Davis Rangelands experiment, which has demonstrated how effectively such strips can filter cattle land pathogens before they enter waterways. One drawback is that these vegetative filter strips, which typically range from 20 to 120 feet wide, do require a significant amount of land.
Where land is at a premium, another possible solution is using decentralized wastewater treatment. New technology can deliver small-footprint, containerized plants to wherever they’re needed to treat agricultural runoff or byproducts of food and beverage production.
In one example, Fluence upgraded the wastewater treatment plant at a small agricultural community in Israel with its energy-saving membrane aerated biofilm reactor (MABR) modules. Because of the wastewater’s high nutrient load, the community was struggling to meet effluent quality regulations. With MABR, the plant has been treating 125 m3/d to a quality high enough for reuse in irrigation.
As New Zealand begins to balance economic growth and water quality, its time-honored tradition of dairy farms may discover a reservoir of new technology waiting to turn hard choices into opportunities.