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Stockholm Conference (1972)


"The discharge of toxic substances or other substances and the release of heat in quantities or in such concentrations that the environment is not able to neutralize the effects must be stopped, so as to avoid that ecosystems suffer serious or irreversible damage. The just struggle of the peoples of all countries against pollution should be encouraged. "


Gothenburg Protocol (2012)


"It establishes national standards for four pollutants: sulfur, oxides of nitrogen (NOx), volatile organic compounds (VOCs) and ammonia, all substances which are able to exercise their negative effects on soil, vegetation and water at distances of thousands of kilometers from their sources and often in countries other than those in which they were produced "


World Climate Conference (2015)


Ban Ki-moon:

"An opportunity that might not come back! We need a significant and strong climate deal to stay below two degrees of temperature increase, also to ensure peace and international security. the summit's objective is to reach an agreement that would allow limiting within the two-degree increase in global temperature, combating CO2 emissions. You have the power to ensure the well-being of current and next-generation, finding a deal to stem the rise of the planet's temperature caused by the pollutants emitted "


Nitrates Directive (1991)


The Nitrates Directive aims to protect the quality of water in Europe by preventing pollution of groundwater and surface water pollution caused by nitrates from agricultural sources and promoting the use of good agricultural practices.

The application within the Member States was exhausting and varied, often not in line with the will of the European Council and this has led to the formal notice of several nations, including Italy. Compliance with current legislation at EU level, national and regional levels for the protection and restoration of waters against pollution caused by nitrates from agricultural sources, and compliance with the Code of Good Agricultural Practice, is a guarantee of protection of water resources and more general protection of natural ecosystems.

Farmers increasingly look favorably towards environmental protection and experiment with new techniques such as the treatment of livestock manure.

Agriculture remains a major source of problems for water and it is necessary that farmers continue to adopt more sustainable practices. still it requires enormous efforts so that we can restore optimum water quality throughout the European Union.

Member States have designated as vulnerable zones the catchment areas in waters within or potentially subject to nitrate pollution and even Austria, Denmark, Finland, Germany, Ireland, Lithuania, Luxembourg, Malta, the Netherlands and Slovenia have decided to provide the same level of protection to their whole territory.

Member States were called upon to define codes of good agricultural practice, to be implemented on a voluntary basis in their territory, and develop specific action programs that farmers are compulsorily required to implement in nitrate vulnerable zones. The designation of vulnerable areas should be reviewed regularly in order to monitor the effectiveness of the action programs, and to modify, with the aim of ensuring that this policy is in line with the objectives of the Directive; Member States are ultimately required to submit to the Commission the results of those checks.


The Nitrates Directive is closely linked to other EU policies on water, air, climate change and agriculture and its implementation brings benefits to each of these areas:


  • Reducing nitrates is an integral part of the Water Framework Directive (2000), which provides an integrated and cross-border approach, aimed at the protection of water and organized on the basis of river basin districts, with the aim of achieving good status for all European water bodies by 2015;

  • the Directive on groundwater (2006) confirms that nitrate concentrations must not exceed the threshold of 50 mg / l. Several Member States have set for even more stringent limits, with the aim of achieving the good state of their waters;

  • Air and soil quality: agricultural and livestock activities are due, among other things, emissions of ammonia (NH3), which have an impact on human health and the environment as they contribute to the acidification process soil eutrophication and ground-level ozone pollution, and other pollutants, such as sulfur dioxide, nitrogen oxides, volatile organic compounds. The full implementation of the Nitrates Directive should contribute to the reduction of ammonia emissions by 14% compared to 2000 levels by 2020, because, for example, measures to limit the quantities of fertilizers used have positive effects in terms of reduction of losses of nitrates in water, both of the ammonia in the air emissions;

  • Climate change: all activities related to farming and fertilizer management release nitrous oxide (N2O) and methane (CH4), a greenhouse gas with a global warming potential of respectively 310 and 21 times that of CO2. If fully implemented, the Nitrates Directive would result in the reduction of N2O emissions by 6% below 2000 levels by 2020. This would help mitigate climate change.

  • So the path that livestock enterprises should and must take to adapt to heavy regulatory constraints appears technically and economically complex.


With the introduction, in vulnerable zones, the threshold of 170 kg of nitrogen from livestock manure per hectare of usable agricultural areas (in areas not considered vulnerable the value rises to 340) but above all with the nitrogen product redefinition by the different animal categories, comes to establishment a new livestock / land load ratio that puts many livestock farms, a time rule, no longer in a condition to be within the new limits.





The key issue is the management of livestock waste, the intensification of livestock and livestock of grilled resulted in a production of slurry per unit area of ​​land exceeding the operating capacity of nutrients by crops, and consequently a high amount of waste to be stored, treated and disposed of in the ground.

The livestock activities in Italy for example, produces large quantities of liquid and solid waste of different types (or shoveled sewage wastewater) originated from livestock buildings and / or processed estimated in the order of about 150 million tons per year.

The productions of biogas are already responsible of the purification of manure which could be alleviated or eliminated, but a high concentration of ammonia nitrogen (more than 1500 mg / l) damages and inhibites the process of anaerobic digestion (Silvana Castelli, 2011).


The parameter considered most important to know the composition of the different types of animal manure, from the environmental point of view is the nitrogen-ammonia.

The current production of manure per unit area of ​​land is excessive in relation to the operating capacity of nutrients by crops.

The excess of these effluents has definitely important environmental consequences

The legislation also imposes a limit on the spreading of manure.


Areas not vulnerable = 340 kgN / ha per year

vulnerable areas = 170 kgN / ha per year.


A common feature of all pigs effluent, but typically also those of cattle and other animals, is the high content of nitrogen, which is found almost completely in ammoniacal (NH4 +) with higher average typical concentrations to the 3000 - 4000 mg / the rise in pig slurry from vulnerable areas.

The liquid waste arising from agro-livestock, when used irrationally or placed outside the agricultural system, account for a significant source of pollution, despite their characteristics make them suitable for re-use in agriculture such as fertilizers or soil.


Environmental problem:


  • ammonia input into the atmosphere through volatilization (particle formation)

  • greenhouse gas emission into the atmosphere

  • Contamination of groundwater by nitrates

  • Eutrophication

  • Possible leaching of slurry (contamination of watersheds)

  • Placing of heavy metals in soils


In this context it is necessary to create a tool that tear down considerably the process of soil pollution.

The plant PuraSystem responds to this need as it is able to treat high amounts of slurry with continuity, breaking down the ammoniacal nitrogen and the total amount of 60 - 80% nitrogen, making it suitable for spreading according to regulatory constraints, without altering the organic properties and without the addition of chemicals as is the case in most of the existing installations.




The machinery capable of purifying waste water by nitrates born from this need: the liquid manure and treated manure can be re-used as an agricultural fertilizer; on the other hand, can be used for the production of biogas, then the organic substance present in the manure can be used for the production of energy. The production of biogas by anaerobic treatment allows to obtain a mixture of methane and carbon dioxide that can be used to actuate a co-generator, producing electrical and thermal energy, or to feed a burner and producing hot water or steam. In the direct combustion and gasification manure must be filtered to remove nitrogenous gaseous ammonia compounds.


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