The potent synthetic fertilisers used in modern industrial farming are a double-edged sword. Sure, they help grow more robust, higher-yielding crops, but the nutrient-rich runoff from these farms can also help incite deadly algae blooms downstream. This new nanoscale filter from GE, however, prevents effluent fertiliser from ever reaching our delicate waterways.
Algae blooms, aka Red Tides, occur when nutrient-rich runoff enters a waterway, fueling a sudden population explosion of harmful algae. These plant-like phytoplankton are capable of decimating ecosystems by producing deadly toxins or consuming the water's dissolved oxygen and suffocating marine life in the area.
While they occur naturally—often timed to the seasonal upwelling of deep ocean nutrients into coastal shallows—algae blooms driven by hyper-fertilised agricultural effluent are becoming more common, threatening downstream tourism and fishery industries. The ZeeWeed Membrane Bioreactor from GE, however, traps these nutrients before they ever leave the farm.
The flexible ZeeWeed membrane is perforated with countless 40 nm (.04 micron) holes—wide enough for water molecules to pass through but too small for protozoa, bacteria, and dissolved phosphorus and nitrogen molecules to do the same. These membranes are made of polyvinylidene difluoride (PVDF) a non-reactive, non-ionic, and hydrophilic thermoplastic coated with a synthetic resin, which allows the membranes to flex and sway in a current, thereby increasing their effectiveness. These bioreactors can be integrated into a number of water treatments—from industrial agriculture to civil-scale wastewater processing.
The bioreactor was recently installed in a wastewater treatment plant near New Zealand's Lake Rotorua, a massive volcanic lake and popular tourist attraction which had been inundated with algae blooms in recent years. "The water being released by the previous treatment plant was still very high in nitrogen and phosphorus, and this was increasing the nutrient loads in the surrounding water courses," said Chris Harpham, sales leader at GE Power & Water for the Asia Pacific region, in a press release.
"We were able to retrofit the ZeeWeed membranes into the existing tanks on the treatment plant site," he continued. "Now that it's operating, it has led to a significant reduction in the nutrient load in the lake." Similarly, the towns of Cairnes and Townsville in northern Australia have implemented the technology, filtering some 189 million litres of wastewater every day before it flows out into the Great Barrier reef and Coral Sea.
Just imagine how much this could improve the health of America's Great Lakes, Mississippi and Colorado tributaries. Even the Gulf of Mexico, which is still recovering from the Deep Horizon oil spill, could benefit. [GE 1, 2 - Wiki]