Approximately 80 percent of mined phosphate rock used in food production does not even lead to consumed food. The element is leached from farm fields and lost in food manufacturing. So although U.B.C. has already commercialized one small corner of the market, it has its eyes on a larger prize: agricultural waste.
The scientists have a pilot effort using the same basic reactor to process nutrients from dairy and pig waste while removing methane. They’re not alone. Researchers are scaling up a variety of projects to minimize livestock’s carbon and water footprint: the nutrient load of one cow is equal to about 25 people. “The domestic wastewater industry has enormous potential,” Mavinic says, “but boy, oh, boy, it’s nothing compared with the agricultural industry.”
Note: This article was originally printed with the title, "Sewage's Cash Crop."
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4 Comments
Add CommentIt is understood that an in-depth analysis of sidebar issues is not practial in a short article like this; but, one major issue should at least be mentioned:
Reply | Report Abuse | Link to thisWith massive concern and proof that synthetic hormones and pharmaceuticals are not being filtered out by current wastewater treatment plants, is this fantastic solution for phosphorus recovery making this problem worse?
Are we spreading MORE of these problem "contaminants" onto our food-growing fields in addition to dumping them in our streams and waterways? Will this strategy be dumping anitbiotics onto our soil and worsening the super bug problems?
A brief follow-up woul dbe helpful.
RZ0001 : The solution is as simple was the treatment of the hole in the ozone layer : BAN hormones in agriculture! All they do anyway is to increase the ammount of water in meat, which is why they are illegal in Europe. Also ban the systematic use of antibiotics in farms. The Swiss banned the use of phosphorous in detergents years ago to preserve Lake Geneva which was becoming badly polluted.
Reply | Report Abuse | Link to thisPhosphorus (P) is an important nutrient for the productivity of grass, crops and farm animals. It is brought onto the farm either through chemical fertiliser or feedstuffs.
Reply | Report Abuse | Link to thisOn a typical 100-dairy cow farm the amount brought on to the farm would equate to approximately 2 tonnes of P per year. However, only 40 percent of this P leaves the farm in produce such as milk, calves and cull cows. This difference between the output and input can be treated as a surplus. The highest surpluses are found on intensive and highly stocked farms with high P fertiliser usage and high levels of concentrates fed. So what happens to this surplus P?
Accumulation in soil
P is accumulating in soils. The build up of P in soils is evident from soil analysis results over the last 50 years. Soils have changed from being predominantly deficient to predominantly excessive in P.
Leached to drainage water
P is held tightly by the soil. However, as soil P levels increase an increasing amount of P is lost in drainage water. The level of leaching is small at approximately 1 KG P/ha/yr, but nevertheless highly significant in terms of nutrient enrichment of water.
Direct run-off
A significant amount of P can also be lost directly to watercourses from farms with poor waste management practices. The most common sources of problems are leaking and overflowing tanks, dairy and parlour washings, and run-off from dirty yards. Run-off from fields following applications of slurry can also lead to significant loss of nutrients including P. Research shows that the risk of contamination of drainage water occurs not just in the days immediately after slurry is applied but continues for a number of weeks afterwards, if water is flowing in the drains.
Addressing the imbalance
In Northern Ireland there is a surplus of approximately 10,000 tonnes of P brought on to farms every year. This surplus will be reduced by the voluntary step taken by the feed industry to reduce the level of P in ruminant concentrates, and the recently introduced Phosphorus Regulations. These Regulations require that farmers must not apply any chemical fertiliser containing P unless there is a requirement. This can only be established through a soil test. Applying fertilisers at the correct amount and at a time when conditions allow uptake of nutrients will lead to greater nutrient efficiency and greater financial benefit. If you find low P levels in some fields you need to ask yourself where has this P gone?
Agricultural use does not lessen the problem of eutrophication, as most of the excess Phosphorus (P) and Nitrogen (N) is from excessive agricultural application of fertilizers. Mostly for the production of animal feeds for factory farms, e.g. beef and pork feedlots, and chicken farms.
Reply | Report Abuse | Link to thisAt least the city sewage is being treated, unlike the agricultural runoff from badly managed farms and feedlots.
"On a typical 100-dairy cow farm the amount of P brought on to the farm would equate to approximately 2 tons of P per year. However, only 40 percent of this P leaves the farm in produce such as milk, calves and cull cows. This difference between the output and input can be treated as a surplus. The highest surpluses are found on intensive and highly stocked farms with high P fertilizer usage and high levels of concentrates fed. So what happens to this surplus P?
1.Accumulation in soil:
The build up of P in soils is evident from soil analysis results over the last 50 years. Soils have changed from being predominantly deficient to predominantly excessive in P.
2.Leached to drainage water:
P is held tightly by the soil. However, as soil P levels increase an increasing amount of P is lost in drainage water. The level of leaching is small at approximately 1 KG P/ha/yr, but nevertheless highly significant in terms of nutrient enrichment of water.
3.Direct run-off:
A significant amount of P can also be lost directly to watercourses from farms with poor waste management practices. The most common sources of problems are leaking and overflowing tanks, dairy and parlour washings, and run-off from dirty yards. "