From Wasteland to Oasis
College of Ag researchers help solve food processing waste problem at Oroville plant
Learning what doesn’t work has been a central part of one of the longest-running research collaborations with private industry and the University. Lal Singh, College of Agriculture, has been involved since 1987 in a research project with Pacific Coast Producers (PCP) to learn how to dispose of the 3 million gallons of wastewater produced daily by processing fruit.
When Singh and former colleague Herb Paul first visited the 800-acre PCP waste disposal tract in Palermo, they were greeted by an overwhelming stench, millions of flies, and a deep layer of black sludge.
Since that time they have created what Singh calls an “oasis” out of the land. Half of the land (400 acres) is devoted to a wildlife refuge and private pheasant club, and the other half is in forage or food crop experimentation.
Through conservation efforts, the volume of wastewater has been reduced to 1 million gallons. Grants from PCP have supported much agricultural research in the 18 intervening years. The efforts have saved the company a large amount of money.
“It is very difficult to quantify the cost savings without access to corporate figures, but it is in the millions,” said Singh. “One could not be in the food processing business without regulatory-approved, cost-effective methods of disposing of the waste.”
Food processing businesses in California are under the microscope of the EPA, water boards, and other regulatory agencies. The alternative to what the College of Agriculture researchers have done with PCP is millions of dollars worth of state-of-the-art water purifying systems.
In addition to dealing with wastewater, Singh and fellow researchers have also explored possible commercial uses of 75 tons of daily fruit waste and have tested forage and food crops that can best adapt to heavy watering and a difficult chemical environment.
Their initial soil profile research indicated that there was a hardpan buildup from unrestricted application of waste for more than a decade. The waste attracted flies during decomposition, and the caked buildup of peach fuzz was perfect for egg laying.
The primary focus of their multidisciplinary research was to learn how to handle land application of food processing waste. In the 1980s, no one else was focusing on the problem.
Professor Buel Mouser, agronomist, planted 10 different types of grasses and clover and applied wastewater as irrigation. From those, he selected a few varieties that were tolerant of processed water and planted them in large, 60-acre fields. He now has an inventory of crops that can tolerate food processing wastewater including cotton, beans, milo, safflower, and elephant grass.
At the same time, engineers worked on application methods that would reduce the collection of water into ponds and on filtration systems to take out solids to reduce the attraction to flies.
Professor Herb Paul, an irrigation engineer, worked on a sprinkler system that would be cost–effective and practical in a situation where the water contained large amounts of solids.
Some of the plans that didn’t work:
They finally settled on land application at the PCP ranch. It required a lot of research, Singh said, to learn how to manage land application and monitor organic and salt contents of soils and groundwater so that it would support plant growth. The challenge was to take care of the waste before the rainy season and to manage the many salts and high pH of the waste.
Professor Mitch Johns, soil scientist, has been responsible for soil research for the last several years. He has focused on the changes in soil chemistry and the fates of organic carbon, sodium, nitrogen, and other elements carried by the cannery water and solids. The research results allow recommendations to be made on the proper rates for sustainable land application activities without compromise to soil, water quality, and plant health.
Professor Henricus Jansen, agroecologist, joined the group in 1999 to help restore native plant species and advise in the management of wildlife refuse.
Much good came from the cooperative project. “We acquired a great deal of practical knowledge regarding the food processing industry using the PCP ranch as an environmentally sustainable model lab,” said Singh. “We helped PCP and the California League of Food Processors address the environmental challenges and work through regulatory requirements. We found answers that were more cost–effective, yet friendly to the environment as well as wildlife at the PCP ranch.”