Agnieszka Makara

Pig slurry is a by-product of non-bedding pig farming. It is a heterogeneous liquid mixture of faeces, urine, spilt feed and water used for waste removal. As it carries large amounts of organic and biogenic substances, slurry can pose a risk for the natural environment; therefore, it should be properly managed. This paper presents methods for the recovery of water and fertilising components from pig slurry using low-pressure (microfiltration, ultrafiltration) and high-pressure (nanofiltration, reverse osmosis) membrane techniques.

Pig slurry is classified as a natural fertilizer of animal origin, being a mixture of faeces, urine, remains of fodder and water used for the elimination of faeces. It is generated in non-bedding pig farming conditions, where animals are kept on slatted floors (grate or slotted floor). This paper presents the general characteristics of pig slurry, its physicochemical properties and its microbiological composition. Also, factors affecting slurry properties are discussed.

Intensive non-bedding pig farming results in the formation of large quantities of liquid waste in the form of slurry. In areas with high concentration of pig farms where we have to deal with insufficient acreage of arable land there is often a difficulty with management of pig slurry’s surplus. The solution to this problem may become a separation of slurry into solid fraction, rich in phosphorus and liquid fraction, which contains mainly nitrogen and potassium. The paper presents the fractionation of pig slurry using sedimentation and pressurized filtration.

Plazma krwi zwierzęcej zawiera ok. 91% wody, dlatego wymaga zatężenia przed właściwym suszeniem. Przedstawione wyniki badań wykazały przydatność technik membranowych. Zawartość białka we wszystkich otrzymanych filtratach wynosiła od 0,15 do 0,26%, niezależnie od jego stężenia w plazmie. Stężenie białka w koncentracie wzrasta wraz ze stopniem zatężania. Dla surowca zawierającego 6,05% białka, przy 2,3-krotnym zatężeniu było równe 13,84%, zaś 3-krotnym 18,24%. Wydajność procesu filtracji membranowej jest stabilna w czasie. Membrany nie wykazują tendencji do zatkania się. Wydajność filtracji wzrasta z temperaturą i maleje wraz ze wzrostem stopnia zatężania. Dla obu użytych membran przepuszczalność osocza jest porównywalna, jednak membrana 0,07 μm ze względu na wyższą skuteczność filtracji (30%) jest preferowana do stosowania w skali przemysłowej.

Dried animal blood plasma, which is offered to the market as a feed product, should meet appropriate standards of quality and epidemiological safety. That is why blood drawing, its transportation, storage and processing must be performed with absolute observance of the principles of hygiene and sanitation. The paper discusses the possibilities of application of techniques used in the food industry for the pretreatment of animal blood plasma to ensure a high quality of the final product. Both the proper treatment of this by-product from the animal’s production as well as its recycling and re-use as a feed or food additives are examples of practical use of cleaner production methods.