Trees soak up lagoons full of hog manure

http://msnbc.msn.com/id/3719258/

Trees soak up lagoons full of hog manure
North Carolina hopes to turn research into practice

The Associated Press
Dec. 16, 2003
WHITAKERS, N.C. - After years of struggling with the dirty disposal problem of sludge from hog waste lagoons, researchers have come up with a possible green solution -- poplar trees that suck up the waste like soda straws.

If the procedure works well enough to be approved by state water quality officials, it could more than cut in half the cost of closing a waste lagoon, currently done with bulldozers and dump trunks.

"It is a simple method," said Frank Humenik, coordinator of the animal waste management program at North Carolina State University.
Humenik has been working with Oregon researchers who have been experimenting the past few years with technology that relies on groves of fast-growing hybrid poplars to suck up waste.

Studies have found the trees can absorb nearly 3,000 gallons of effluent per acre per day, ridding the ground ammonia and nitrogen by safely metabolizing the compounds in their woody tissue. Oregon State University water quality researcher Ron Minor said it could take 10 years before the trees clean the land well enough that it can be used again. "Over time, the trees take up the nutrients and it is natural purification," Humenik said. "With the trees, you have a harvestable product."<snip>

Nitrogen and bacteria laden liquid effluent is distributed through plastic tubes to drip ports buried shallowly in the soil. Grass grows on top and metabolizes the nitrogen compounds (ammonia). Aerobic bacteria consume the other "nutrients".

These systems are employed in unique circumstances.

hog farm lagoons are one of man's WMD's that needs to be dealt with.

The existence of intensive factory farms is the problem. Shit lagoons are the symptom.

if it could be used in large scale efforts to grow plants (such as these poplars) that could then be used to make ethanol or biodiesel (etc) - and with the looming "end of the petroleum" - such efforts might even be economically feasible fairly soon.

the bigger problem, of course, is the tremendous cruelty inherent in the factory farming of sentient creatures.

This is a concept that's been around for quite some time -- about 15 years in the U.S. and longer in the UK.

The idea of poplars acting as a soda straw is accurate in some ways, but the trees are acting more like a straw with a filter on the bottom because only water and dissolved substances will enter into the tree. The vast majority of the organic waste and the organically-bound nitrogen and phosphorus will remain in the lagoon. However, the trees are highly effective at dewatering and removing soluble components.

Although I very much support this system, some of the limitations of the approach need to mentioned:

• Being deciduous trees, they will only be active at removing water and solutes when there are leaves on the trees. In the winter, the lagoons will continue to function as if the trees weren't even there.
  
• A potential problem has to do with the liners beneath the lagoons. The roots are aggressive and strong and can easily penetrate clay liners. Plastic liners are similarly subject to stress and potential failure.
  
• The trees have the nasty habit of putting out some levels of gaseous nitrogen. Certain gaseous nitrogen compounds can act as a greenhouse gas and/or a component of acid rain.
  

I totally agree with one of the comments on this thread that the real problem is putting so many animals in a limited area. Farms with reasonable animal densities can handle the waste problem through land application and proper management.

Has anyone asked the trees about this? I bet they HATE that.......