best available technologies for manure treatment - Baltic Green Belt

Best Available Technologies for manure treatment baltic sea 2020
Best Available Technologies for manure treatment baltic sea 2020
ANNEX E: TABLES WITH SHORT DESPRIPTION OF LIVESTOCK MANURE TREATMENT TECHNOLOGIES
Best Available Techniques for manure treatment - for intensive rearing of pigs in Baltic Sea Region EU Member States Technical Report "Best Practice Manure Handling, Phase 2"
Ref No. 24 Adding other chemical to manure, here under enzymes
Brief description
Description of the effect on leaching (positive or negative) of N
and P
Under the generic denomination of manure additives are a group of products made up of different
compounds that interact with the manure, changing its characteristics and properties.
These products are applied to the pig manure in the pits, and the following effects are described to
different degrees in the label of every product:
1. a reduction in the emission of several gaseous compounds (NH3 and H2S)
2. a reduction of unpleasant odours
3. a change in the physical properties of the manure to make easier its use
4. an increase in the fertilising value of the manure
The effects on leaching in concerning N related with the additive
effect on emission on ammonia and other N compounds. Less
emission of ammonia emissions means that less N could return
as atmospheric deposition and that more N is re-circulated in
the agricultural production rather than ending in the
environment.
The effect on P leaching is associated with the use of additives
in processes to separate the manure in fractions, allowing the
fibre fraction with a high content of P to be exported to areas
with a low livestock density.
5. a stabilisation of pathogen micro-organisms.
Usually, the items 2 and 3 are the main reasons for their use at a farm level. Below the techniques 1 – 5
are detailed.
1. Additives for reducing the emission of several gaseous compounds: The decrease in gaseous
emissions achieved through its use (mainly NH
3
and H
2
S) is one of the most interesting yet controversial
points. It has been well documented that up to 90 % of the N produced by the pigs is as urea. When the
urease produced by faecal micro-organisms comes into contact with urea, the following reaction occurs:
CO(NH
2
)2 + 3 H
2
O 2 NH
4
+ HCO
3
+ OH
This reaction is highly influenced by temperature and pH, for example, under 10 °C or at a pH below 6.5
the reaction stops.
2. Additives for reducing unpleasant odours: Odour results from the mix of different compounds under
anaerobic conditions. More than 200 substances involved have been identified, such as:
volatile fatty acids
alcohols (indol, skatole, p-cresol, etc)
H
2
S and derivatives
ammonia
other N compounds (amines and mercaptans).
There is a huge variation in the proportion and concentration of every substance depending on the type
of farm, nutrition and nutritional management, and climatic conditions. This could explain why in many
instances the effectiveness of these compounds against odours could not be proven under farm
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