Why agriculture factories refuse to use sludge as fertilizer?

Question

Why agriculture factories refuse to use sludge as fertilizer?

Answer 1

which type of agri waste either from Animal origin or Plant?

though it,s from animals, it contain lots of bacterial loads & also depends on which type of treatment given before use as fertilizer. I have one artical regarding to teratment methods of sludge originated from seafoods wastes though u requried plz tell me.

Bharat (M.F.Sc)

Answer 2

First, there are no agricultural "Factories".  There is not assembly line in growing plants.  This is a journalistic shock term, not a true description of agricultural production.

Second, the use of sludge involves a great deal of regulatory activities.  Consequently, the value of sludge as a fertilizer drops considerably as the amount of paperwork increases.  Every minute spent doing this paperwork is a minute not doing something else related to crop production.

Third, sludge is not an acceptable fertilizer for all agricultural crops.  Consumer acceptance of "sludge" aka human waste is somewhat limited.  The potential to spread disease with raw vegetables (Think, E. coli is found only in animals and animal waste, yet tons of spinach have recalled because of E. coli contamination) is rather high.

Fourth, Sludge is not a balanced fertilizer.  Often it has a high concentration of phosphorus in relationship to nitrogen.  The agricultural crop often requires 3-5 times more nitrogen than phosphorus.  If the sludge is used as a nitrogen fertilizer, phosphorus is over applied.  Phosphorus is a known pollutant in many surface waters.  Consequently, if a farmer's soil already has excessive levels of phosphorus, the use of sludge would be a cause of surface water pollution.

Answer 3

Animal offal could be present, risk of mad-cow disease.

Answer 4

to much heavy metals in the sludge...causes a long term effect determinable to soils

Answer 5

With our water based collection of manure in the sewers, we have a very high degree of leaching, the plant nutrients end up mostly in the water that leaves sewage treatment plants. The process of reclaiming water and reclaiming plant nutrients is then resolved to using the water to irrigate crops.

The sludge at the end of the process has very little value as fertilizer because most of the plant nutrients, are soluble and left with the water.

We are left with slow to decompose cellulose that does have some benefit in maintaining soil tilth, storing water in the soil. But it comes with risks that arise from people disposing of things down sewers that should not go into sewers if we hope to use sludge for soil amendment. (I use that term because its value as fertilizer is so low.)

Answer 6

There is a public perception that sewage sludge is toxic in any and all forms.  Just the sound of the words seems to turn people's stomachs.

The 40 CFR Part 503 regulations were promulgated by the USEPA in the early 1990's and adopted by states in various incarnations.  The 503's attempted to change the public's perception by redefining sewage sludge as 'biosolids'.  The 503's also placed rigorous monitoring and treatment requirements on biosolids proposed to be used as fertilizer.

The biosolids application rate is based upon the nitrogen requirement of the crop to be grown.  This 'agronomic' rate is checked against a maximum single and lifetime application rate for the various heavy metals (cadmium, copper, lead, nickel, zinc, and molybdenum) that may or may not be present in the material.  Reporting requirements are also rigorous and are generally the responsibility of the generator of the biosolids.  Typically, this is the wastewater treatment plant.

Granted, phosphorus levels do increase with long term biosolids use, and there is concern about the solubility of phosphorus in the soil and its impacts on surface water bodies.  But the nitrogen benefit is significant.  The inorganic nitrogen fraction is available for immediate plant uptake and the organic nitrogen component is time released over several growing seasons.  Crops that are fertilized with biosolids are not direct food chain crops.

Next, look at the alternatives to biosolids based fertilizer products.  Nearly all fertilizers are derivatives of the petrochemical industry and are very expensive.  With the price of crude oil around $100 a barrel shouldn't we be looking at alternatives?

In the mid-Altantic region and throughout the northeast the public screamed bloody murder when it was discovered that most sludge from cities near the coast was dumped in the ocean.  Around here the development of land-based alternatives to ocean dumping of sewage sludge was the environmental bandwagon of choice in the late 1980's & early 1990's.  At that time the easiest and least capital intensive alternative disposal method was determined to be beneficial reuse through land application.  (I believe that the 503 regs were actually developed with this malice aforethought.)

Be that as it may in the mid-90's new incinerator capacity became available and the cost for this method of sludge management dipped below the cost for land application.  Currently, incineration is very cost effective as a management (read this as disposal) method.  But when the cost per gallon for incineration goes up maybe beneficial reuse of the biosolids through land application will again be desirable.

Today the bandwagon is global warming.  Why doesn't anybody remember that the ice ages in the past had to be preceded and followed by significantly warmer epochs?

I often wonder where the so called 'green' people live and whether or not they really give a d**n about the environment or if they simply need a bandwagon on which to ride.  Because when they move from the city to the country they sure as sh*t don't want sewage sludge used in their backyards!  Even if it is called biosolids.

Finally, I have to note that at least Al Gore invented the internet before he invented global warming.  That way I can spend a dreary Saturday afternoon between football season and college hoops season writing this ridiculous diatribe.