The sewage, wastewater or livestock effluents are the wastes that are produced inside an animal farm. They are composed of liquid and solid excrements such as urine and feces, materials of vegetable origin, water used to wash animals or to water them and food remains.
In traditional farms, these sewages were mostly formed by manure and were disposed of in the form of fertilizer, therefore in a sustainable manner. With the spreading of manure in the soil, it was possible to maintain the chemical and mechanical fertility of the cultivable surface. This is why manure was considered a precious commodity that was reused within the company or sold.
It should be added that the quality of the fertilizer produced depends very much on the type of barn that is chosen to raise their animals. Due A cattle sheds offer a wide choice in terms of stables, everything depends on what you want.
But what happens in intensive farming? The quantity of livestock is greater than in traditional breeding and, consequently, the quantity of sewage produced exceeds the absorption power of the soil and becomes polluting.
The pollution, in this case, is given by the large quantity of nitrogen and methane products that decrease the quality of the oxygen present in the waters. And if these waters are intended for human use, there is also a possible increase in pathogens.
A solution to this problem may be to use a biogas plant. A plant of this type optimizes the production of gases produced by the bacterial fermentation of organic animal or vegetable remains to transform everything into renewable energy.
Proper waste management opens the door to ecological and hygienic problems that, over time, have become the subject of regulation. In our country, the use of livestock slurry was regulated by Legislative Decree no. 152 of 11 May 1999. Today it is regulated by Legislative Decree 152/2006.
Types of sewage
Depending on the species being bred and the technique used, the residues produced are different, both in terms of their composition and in terms of their pollution index. The management and disposal techniques therefore also vary.
For the disposal it is important to understand the manure of the slurry, that is if the wastewater can be considered solid material or not. In general, everything that forms a mound is semi-solid, then manure, sludge derived from purification and compost.
The non-semi solid residues are those that do not form heaps and must therefore be stored in tanks or cisterns. In this category of sewage, we find the dejections that have no addition of litter, or that in any case contain a minimal part of it, with the addition of water used for washing.