Scientists in China have developed a way of making fertilizer from wastewater discharged by potato processing plants, solving a pollution problem that has held back the country’s potato ambitions.
China sees potatoes as a promising staple food to ensure food security, but protein-rich water discharged by starch processors—a major buyer of potatoes—has been blamed for polluting rivers and lakes.
“For years, there has been no technical solution to this problem, forcing environmental authorities to close more than 10,000 small plants, which has hurt the potato market and farmers,” said Liu Gang, researcher with the Chinese Academy of Sciences and Lanzhou Institute of Chemical Physics.
Liu’s team has developed technology that can halve the chemical oxygen demand (COD) of the effluent by removing starch, fiber and protein. The processed water does not need to be dumped either, because its high nitrogen, potassium and phosphorus content make it a perfect irrigation water.
A four-year test has shown the water harmless to crops, and three starch companies are now using the technology to purify their discharge.
China is the world’s largest potato producer, with nearly 14 million acres in potato production. Given its resistance to cold and drought, the crop is more suitable for cultivation in China’s arid west and northwest than wheat and rice are.
The Ministry of Agriculture has plans to expand potato acreage to 25 million acres to produce 50 million metric tons by 2020.
Chinese companies have developed buns, noodles and other products made from potato starch, products that are more familiar to the Chinese as staple foods.
Source: Shanghai Daily