# Using sewage sludge to fertilize crops

Discussion in 'Earth Science' started by Plazma Inferno!, Aug 16, 2016.

1. ### Plazma Inferno!Ding Ding Ding DingAdministrator

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A new study suggests sewage sludge could serve as a sustainable and effective plant fertilizer.
Phosphorous is essential to the diets of both plants and animals. In commercial agriculture, fertilizer ensures crops get enough of the vital nutrient.
The production of commercial fertilizers requires a lot of energy. Thermally treated sewage could serve as a sustainable substitute, researchers say.
When scientists fertilized ryegrass plots with thermally treated sewage and commercial triple superphosphate fertilizer, they measured comparable soil and plant benefits. Thermally treated sewage encouraged improved shoot growth and suggested the potential for greater root development.
Though commercial fertilizer allowed for more uptake of phosphorous, the diversity of nutrients in the sewage sludge encouraged microbial activity that immobilized phosphorous. Thus, phosphorous that wasn't immediately absorbed by plant roots remained in the soil for later use.

http://www.upi.com/Science_News/201...izing-crops-with-sewage-sludge/6821471288449/

Study: http://journal.frontiersin.org/article/10.3389/fnut.2016.00019/full

3. ### billvonValued Senior Member

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We've been doing something like that for a few million years, so it's nothing new.

One thing that IS new, though, is that sewage now contains a large number of pretty potent drugs. (Most drugs are excreted like anything else from your body, and people are taking more drugs than ever.) That has to be taken into account.

5. ### iceauraValued Senior Member

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Also, humans feed high on the food chain - which means (in modern economies, with industrial meat supplies) that not only drugs but heavy metals and other industrial pollutants (flame retardants, pesticides and herbicides, disinfectants, various plastics and their solvents/components etc) become concentrated in human shit.

As far as I know, there has been no solid and reliably informative research into prion transmission via human waste. There are suggestive studies and findings of varying quality: http://www.alzheimers-prions.com

In that line, note that uptake by plants is not the only issue - wind and rain and surface deposition also factor in.

And, not to beat a drum in the wings, but nitrogen and phosphorus runoff from inorganically fertilized fields - industrial as opposed to "organic" agriculture - being as significantly damaging a factor as it is, this is worth underlining:
That has implications far beyond the immediate concern. "Organic" farming - could use some serious, modern, well-funded research.

7. ### timojinValued Senior Member

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Chicago as any large city processes its waste drys ( removes water ) by evaporation from sludge ponds for many many years . Sells the product to Saudi Arabia and other country .
I use my septic field sludge to fertilize my grass, That is nothing new in this area . I have been told Sarasota Florida uses the processed effluent for irrigation.

Our sanitary system in chicago have a long going research by using dewatered sludge in farming in Fulton county , It have been known that using our sludge for lattice farming contains less Cadmium per pound then California San Joaquin valley [product.
So why more dump money , let the do paper research then give more tax payers money

8. ### JeevesValued Senior Member

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I've heard that sludge has been used as fertilizer for a couple of decades in America (though not publicized), and is, or has been, classified as "organic". The catch is, some or all of that was industrial sludge, and contained all kinds of chemicals you don't want in your salad. http://whyfiles.org/063recycle/toxic.html

9. ### timojinValued Senior Member

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3,252
What do you think should be done with the sludge in a city over one million population ? How do you get rid of it ?
Of you are in small city you should be concerned from where the water have been pumped and how deep is the well, for Radon and Radium,

10. ### JeevesValued Senior Member

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Of course you should be concerned, wherever you live.
Of course, both local food and water should be tested regularly for contaminants.
Most residential waste doesn't require a whole lot of treatment before it can be used for fertilizer, and it's a good idea to reclaim grey water, as well. It's a good idea - will soon become imperative - to grow as much food as possible in and near the cities.
But industrial and chemical waste needs to be handled separately and much more carefully than is the case in North America. Companies should be held far more accountable for what they dump on everyone else to pay for, while getting tax-breaks or subsidies themselves. Farmers should have abandoned the use of chemical fertilizers (which can be used a whole lot easier than cow patties in bomb-making - or so I've heard) and pesticides (which are wiping out the insects that pollinate the crops) and herbicides (which are rendering the soil inert), all of which poison the ground-water. Fracking and drilling, oil pipe-lines and open pit mining, garbage dumping and the burial of radioactive waste are all crazy things to allow.

11. ### billvonValued Senior Member

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As long as you can justify the dramatic cost increases in food, and the resulting increases in worldwide rates of starvation. "Just let them die" might not get too much support, though.
None of the above are "crazy things to allow." They just need to be regulated to prevent abuses and environmental damage. An oil pipeline, for example, is FAR FAR more environmentally friendly than trains or tanker trucks delivering the same amount of oil.

12. ### JeevesValued Senior Member

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Why justify something that doesn't need to happen? Grow your food close to home, get it fresh, get it cheap. Poisoning America's water and food never prevented a famine in Asia or Africa. Nor will it stop the climate change that kills the glaciers and dries up the rivers.

Regulated. The legislatures the oil companies have by the short and curlies are going to regulate their patrons? So far, they've done a heck of a job, Brownie!
Who says we need to move the crap around at all? Leave it under the ocean, under the forest... what's left of it. Use clean energy, and use it a lot more intelligently than we have been.
(I know it's a pipe-dream. Really, we're just going to be stupid https://www.youtube.com/watch?v=va_MVxpboqg to the last drop https://briarpatchmagazine.com/articles/view/stupid-to-the-last-drop and then die. Slowly, nastily.)

13. ### billvonValued Senior Member

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Not really practical for people living in the desert unless you divert rivers and use chemical fertilizers on desert sands. (They're actually taking your advice; the desert near El Centro is now growing a lot of food.)
The cheap food brought about by chemical fertilizers, high yield crops and artificial irrigation absolutely ameliorates famines in Africa. We sent 1.4 million TONS of food to Africa in 2013.

Now, you can argue that that's immoral, that we should just let them starve (or tell them to grow their own food, or whatever.) But again, that's a hard sell.
They certainly have.

The first time I was in Los Angeles was in 1978. Back then people were being told to move because the air was so bad. You couldn't even see the mountains. Eagles were dying, rivers were catching on fire and sludge was being dumped into streams.

Today LA air is between 50% and 90% cleaner (depending on pollutant) than it was 40 years ago. Rivers are cleaner overall. There is less particulate pollution in the air. Even though there are more cars than there ever have been, they get better gas mileage, are more powerful, and safer overall.

Do we still have more to do? Definitely. But we are headed in the right direction.
Who? Almost anyone who wants to drive, fly or go by train. Anyone who wants textiles, medicines or plastics. Anyone who wants roads.
Clean energy is great. It won't power airplanes or replace all the cars on the road or make plastics for us.

14. ### JeevesValued Senior Member

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Airplanes. Plastics. You're still in the dead-end-box. Most people are.

15. ### billvonValued Senior Member

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Why do you think that?

16. ### JeevesValued Senior Member

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Because in the last 50 years, since we've known to a certainty that we're in imminent and profound sludge, all the efforts of all the major players have been exerted in the interest of preserving an obviously unsustainable status quo, with the result of destabilizing, antagonizing, deforesting, eradicating, endangering and generally making an ever bigger, deeper ocean of even darker sludge.

17. ### iceauraValued Senior Member

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Destroying local food security is not adequately addressed via charity food shipments. Not that they are bad in themselves, mind - once you have created a famine, you are almost morally bound to feed its victims - just that it doesn't work as a long term solution. Particularly when the production of the food is damaging the base of the food supply in its home country.

18. ### billvonValued Senior Member

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That's not true at all. The government has poured billions into renewable energy. Entire companies (SolarCity, Tesla, Ballard, First Solar, SunEdison, Sunpower, Trina, Solaredge, Xantrex) have started in order to "change the status quo." Toyota, Honda, GM, Ford and Mitsubishi all have non-fossil-fuel cars.

Do you generate your power via solar? Drive an electric car? Work in the field of renewable energy? If not, why not?

19. ### iceauraValued Senior Member

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They have electric cars. Whether they are "non fossil fuel" or not depends on how they get their juice.

Billions are a drop in the bucket, and easily explained as political show.

20. ### billvonValued Senior Member

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And hydrogen fuel cell cars. And methane cars, which can be powered from biogas. And E85 cars.
Agreed. Here in CA we are up to about 20% renewable energy - and climbing rapidly.
The 1 million+ solar installations throughout the US are not so easily dismissed.

21. ### JeevesValued Senior Member

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1,651
The Obama government, yes? And look at the flak they took for that effort! And how much of that money was quietly pocketed by top executives of corporations, instead of going to the thinkers and makers? No co-ordinated national strategy. When he bailed out the automobile industry, it shouldn't have been predicated on reducing the work-force, but on converting to public transit and clean fuel. Will the next administration cancel everything because "climate change is a lie invented by the Chinese" - just as Reagan had Jimmy Carter's solar panels ripped off the white house? Probably not, but she'll put more resources toward international conflict and intelligence than dealing with the natural and unnatural (oil leaks e.g.) disasters at home.
There is a lot of innovation, clever people with good ideas. But they have limited resources and no political power.

And what percent of the population can afford these products? How long before the average single mother with two part-time jobs can drive a Tesla? There was a credible run at this back in 1907 or thereabouts, and again some 20 years ago, only to be stifled by the oil-burners. There were windmills all over the countryside in 1900, only to be replaced by that huge, unsightly electric grid. Not nearly enough local power generation initiatives, even though we're finally seeing some larger endeavours, especially in India and Europe.
A lot of time has been squandered.

Yes. Have done for 30 years in a small way, expanded to the whole house three years ago.
No, I'm holding out for a car with solar skin. Probably settle for a motorized tricycle.
Retired, so work in my own greenhouse and veg garden. Also buy only used clothes and shoes, recycle everything possible, take my own canvas shopping bags and buy as little packaging as I can - which is damn hard! And it's nothing, in the face of waste by big companies.

Last edited: Aug 19, 2016
22. ### billvonValued Senior Member

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Well, and the first Clinton administration, and the Bush administration. And yes, they all took flak for that - partly because the very first such effort, under Carter, was a disaster. But since then, they've gotten much better.
Like Musk? He pocketed a lot - and did a lot with it. He single-handedlly turned public perception of EV's from slow econoboxes that would strand you miles from a charger to the fastest cars on the road.
Well, then it wouldn't have been bailing out the automotive industry, it would have been shuttering it. Fortunately, a large amount of the bailout money DID go towards cleaner/more efficient cars.
A large (and growing) number. There are now companies (in states with good incentives) that will install solar power on your home for free - and send you the power bill every month instead.
About two years, when the Tesla 3 comes out.

But why a Tesla? Why not a used Prius plug-in or a 2012 Leaf? Way cheaper.
Not really physically possible; it would take days to get enough charge that way to drive even 10 miles.

But electric cars are available today - so why not buy one? Answer that and you will have the answer to why alternatives are not developing more quickly.

23. ### JeevesValued Senior Member

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Because I have no \$. And that is the bottom line for most people. About the the single mother earning minimum wage, you haven't got a clue, have you? Prius? Leaf? She's barely making the health insurance payments and sure as hell can't get a car loan!
There is a lot of promising activity, yes. But it's too random, too late and not directed at the people who most need it.