Featured Research

from universities, journals, and other organizations

Recycling and depolluting the phosphorus in livestock waste

Date:
December 6, 2010
Source:
Cemagref
Summary:
Phosphorus is an ingredient in agricultural and household products such as fertilizer, detergents, etc. When released in excessive quantities to the environment, this mineral contributes to the development of algae and micro-organisms that pollute water, thus impacting on fishing, fish farms, swimming areas and drinking water. Scientists are now developing a means to recycle the phosphorus present in animal effluents and limit water pollution.

Phosphorus is an ingredient in agricultural and household products such as fertiliser, detergents, etc. When released in excessive quantities to the environment, this mineral contributes to the development of algae and micro-organisms that pollute water, thus impacting on fishing, fish farms, swimming areas and drinking water. At Cemagref, scientists are developing a means to recycle the phosphorus present in animal effluents and limit water pollution. The new process may represent a solution for the future, given the depletion of natural phosphorus and the resulting increase in farm operating costs.

Related Articles


A product of mined phosphate rock phosphorus is an indispensable element for life. In agriculture, it is used in mineral form to boost the growth of crops and animals. However, if it is incorrectly assimilated or used in excess, large quantities are subsequently released to the environment through erosion and run-off. In areas with intensive crop farming and/or animal production, over 50% of the phosphorus in rivers is the result of such diffuse pollution. A further source is the phosphorus used in detergents that is released in household wastewater. The excessive quantities of this mineral cause eutrophication in rivers and the development of certain bacteria that impact on water quality, thus affecting fishing, fish farms, swimming areas and drinking water.

Recycling in addition to good agricultural practices

To limit these risks, the regulations on spreading of phosphorus-based products now encourage farmers to reduce quantities of fertiliser. But in intensive animal-production zones such as Brittany, the quantities of phosphorus (and nitrogen) produced via animal effluents and available as fertiliser exceed the amounts needed for crops. How can the manure be treated to recover the phosphorus so as to be transportable to other regions, thus limiting pollution levels?

At Cemagref, scientists are developing processes to recycle phosphorus, whether from wastewater-treatment plants or agricultural effluents, so that it can then be used as a direct substitute for phosphate-based mineral fertilisers. A team is paying particular attention to the various types of phosphorus contained in livestock effluents and how they are modified during treatment. Between 60 and 80% of the phosphorus is in the form of mineral particles that settle with the organic matter.

A four-step process

The team has designed a process to separate the phosphorus from the organic matter in the effluents. It comprises four steps, i.e.

1) dissolve the phosphorus using formic acid, thus making it recoverable in the liquid phase,

2) separate the solids from the solution containing the phosphorus,

3) precipitate the solution chemically by adding magnesia to crystallise the phosphorus, and

4) filter the solution to recover the phosphorus in mineral form for use as a fertiliser. The goal is to obtain large crystals which are easier to filter and dry. Process optimisation depends on improving the separation step, prior to precipitation. If the solids are simply decanted, only 50% of the phosphorus can be recycled, but the crystals are large enough to be filtered. Another technique involves adding a polymer and then straining the solution before precipitation, which results in 80% recovery of the phosphorus, but the crystals are small and difficult to filter. The researchers are continuing their efforts to optimise this essential crystallisation step in order to devise the best conditions to produce large crystals and improve recycling efficiency).

Take action prior to the depletion of natural phosphate supplies

On the basis of current knowledge, phosphorus recycling necessarily includes the acid-dissolution step, whose high cost constitutes the main economic obstacle to wider use of this recycling process. The work carried out at Cemagref on these economic aspects, in conjunction with the European university of Brittany, has revealed that recycled fertiliser is not competitive with imported, chemical fertilisers. However, that should change over the coming decades due to the increase in fertiliser prices caused by the progressive depletion of phosphate reserves and the resulting increase in extraction costs. Though estimations diverge on when phosphorus supplies will be depleted, currently exploitable reserves may be gone within the next century.


Story Source:

The above story is based on materials provided by Cemagref. Note: Materials may be edited for content and length.


Cite This Page:

Cemagref. "Recycling and depolluting the phosphorus in livestock waste." ScienceDaily. ScienceDaily, 6 December 2010. <www.sciencedaily.com/releases/2010/12/101206093508.htm>.
Cemagref. (2010, December 6). Recycling and depolluting the phosphorus in livestock waste. ScienceDaily. Retrieved January 27, 2015 from www.sciencedaily.com/releases/2010/12/101206093508.htm
Cemagref. "Recycling and depolluting the phosphorus in livestock waste." ScienceDaily. www.sciencedaily.com/releases/2010/12/101206093508.htm (accessed January 27, 2015).

Share This


More From ScienceDaily



More Plants & Animals News

Tuesday, January 27, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How To: Mixed Green Salad Topped With Camembert Cheese

How To: Mixed Green Salad Topped With Camembert Cheese

Rumble (Jan. 26, 2015) Learn how to make a mixed green salad topped with a pan-seared camembert cheese in only a minute! Music: Courtesy of Audio Network. Video provided by Rumble
Powered by NewsLook.com
Water Fleas Prepare for Space Voyage

Water Fleas Prepare for Space Voyage

Reuters - Innovations Video Online (Jan. 26, 2015) Scientists are preparing a group of water fleas for a unique voyage into space. The aquatic crustaceans, known as Daphnia, can be used as a miniature model for biomedical research, and their reproductive and swimming behaviour will be tested for signs of stress while on board the International Space Station. Jim Drury went to meet the team. Video provided by Reuters
Powered by NewsLook.com
Husky Puppy Plays With Ferret

Husky Puppy Plays With Ferret

Rumble (Jan. 26, 2015) It looks like this 2-month-old Husky puppy and the family ferret are going to be the best of friends. Look at how much fun they&apos;re having together! Credit to &apos;Vira&apos;. Video provided by Rumble
Powered by NewsLook.com
Scientists Model Flying, Walking Drone After Vampire Bats

Scientists Model Flying, Walking Drone After Vampire Bats

Buzz60 (Jan. 26, 2015) Swiss scientists build a new drone that can both fly and walk, modeling it after the movements of common vampire bats. Jen Markham (@jenmarkham) has the story. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

    Health News

    Environment News

    Technology News



    Save/Print:
    Share:

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins