The present invention concerns an anaerobic digestion of animal manures, energy crops and similar organic substrates. The process is capable of refining nutrients comprised in the digested biomass to fertilizers of commercial quality. The invention also provides a method for oprocessing animal carcasses or fractions thereof including meat and bone meal etc., with the objective of providing an alternative means for processing the organic waste material of animal origin while at the same time facilitating the production of fertilizers. The risk of spreading BSE prions or any other prions to animals or humans is thus substantially reduced if not eliminated. The biogas and slurry separation system according to the present ivnention is preferably integrated with the operations of animal husbandries into a total concept in which the internal and external performances of animal husbandries are optimised. The internal performances concern quality aspects related to the management of the animal houses and include industrial hygiene, animal welfare, gaseous and dust emissions and food safety. The external performances concern mainly energy production and emissions to the environment of nutrients and greenhouse gases and the sale of high quality food product.

Concept for slurry separation and biogas production

A method and plant for the treatment of an organic waste material in liquid form, e.g. liquid manure from livestock, the method comprising filtering fibres and particles from the liquid, subjecting the liquid to anaerobic fermentation in a biogas reactor, separating a substantially sterile and particle-free permeate stream from the biogas reactor, e.g. using ultrafiltration, subjecting the permeate stream to treatment with an ammonia stripper at an elevated temperature and preferably at reduced pressure to remove substantially all ammonia and carbon dioxide and to result in an ammonia fraction and a nutrient salt fraction, and separating the nutrient salt fraction into a fertiliser concentrate fraction and a water fraction, e.g. using reverse osmosis. The end products of the method are clean water, ammonia concentrate, fertiliser concentrate containing salts of P and K, compost and high-quality biogas with a high methane content.

Method and plant for the treatment of liquid organic waste

A process for treating manure using anaerobic digestion includes introducing manure into a mixing vessel containing a digester liquid and agitating and filtering a slurry formed therefrom to remove substantially all water insoluble solids, thereby leaving a liquid containing ammonia and reactive organic materials. The liquid is then heated and ammonia is removed therefrom to produce a substantially ammonia-free liquid containing reactive organic materials, which is cooled and placed in a digester containing anaerobic bacteria to convert the reactive organic materials in the liquid to biogas and to produce a digester liquid. The biogas is withdrawn and utilized to generate electricity, and a small amount of the digester liquid is withdrawn from the digester and recycled back to the mixing vessel. The water insoluble solids and ammonia removed during the process may be converted to ruminant animal feed and concentrated liquid fertilizer, respectively.

Process for producing energy, feed material and fertilizer products from manure

The present invention in a first aspect provides a method and a system for stripping volatile compounds such as ammonia from eg fermentation liquids Part of the ammonia is stripped form the liquid in a stripper system comprising a shunt through which liquid such as eg fermentation medium comprising a biomass can be diverted in the form of a side stream in liquid contact with a main fermentor(s) The stripper system is connected to an evaporator In the evaporator aqueous liquid is heated at a pressure below atmospheric pressure whereby vapour is developed at a temperature below 100°C The vapour from the evaporator is directed to the liquid medium comprising ammonia and this results in ammonia being stripped from the liquid and transferred to the vapour phase The vapour phase is condensed in first condenser at a low pressure, eg a pressure well below 1 bar, and the liquid thus obtained is further treated in a stripper unit at a higher pressure, such as eg a pressure at or above 1 bar, to obtain a more concentrated solution of ammonia When stripped for at least part of the ammonia the liquid initially obtained from the biogas reactor and diverted to the shunt can be returned to the reactor

Method and device for stripping ammonia from liquids

The invention relates to a method for processing organic material, in which method bioconversion is performed on the organic material in at least one first reactor, the biogas formed in the bioconversion is treated with ammonia in the at least one second reactor and buffer solution produced in the second reactor is recycled to the bioconversion in the first reactor. Thus the carbon dioxide of the mixed methane/carbon dioxide gas reacts with the ammonia and forms a buffer compound, such as ammonium bicarbonate and/or ammonium carbonate.

Method and equipment for processing organic material

Process for the preparation of liquid manure from cattle excrement, if appropriate after fermentation resulting in the production of methane, the liquid manure first being alkalinised with lime, before the separation of the sludge obtained and the conveyance of the residual water at the head of a rectifying column, in which the ammonia is driven off by steam, of which the condensation with the ammonia gives ammonia water, in which the ammonia is fixed to carbon dioxide to give ammonium carbonate as a result of the contact of the ammonia water with the biogas or with the fumes obtained as a result of the combustion of the biogas, the residual water being sterilised during the extraction of the ammonia.

Cermak Jan

Papers

Process for the treatment of liquid manure coming from the excrement of cattle bred for profit

Verfahren zur verarbeitung von jauche aus exkrementen von nutzvieh