Acidification or the slurry at pH values of 4.5, reduce in a significant way the emissions of harmful gas. However disadvantages are associated with the use of abrasive mineral acid while considering handling and nutrient balance. A new method using lactic acid (50% concentrated) present some advantages for the reduction of emissions and also for the handling of the acid and the acidified slurry. For acidification of slurry to a pH values of 4 to 5 demands the addition of lactic acid (50% concentrated) of about 5% by volume. Such reduction of pH value leads to a reduction of 90% ammonia and methane emissions. Nitrous oxide emissions come only from non-acidified slurry that encrusted and the emissions in such conditions come only after the ammonia emissions has decreased significantly. The effect on the reduction of the emissions are seen also at the application time and no negative effects of the acidified slurry have been detected on the soil or plants; the results obtained even show higher yields. The specific costs associated with manure acidification are comparable to those of biofilters and bioscrubbers, however the reduction of emission potential is 3 to 5 times higher.

The experiment was conducted during three finishing periods (25 to 115 kg liveweight). The annual costs are compared on the basis of a 1840 pigs house. More equipment (discharging system, pH-meter, mixing facility, electricity costs, etc.) and labor are needed to realize the acidification process. The long term effect of acidified manure fertilization are not discussed and no information is given on what happen to manure pH during storage. The total annual extra cost for the organic acids are $20.00 CAN/pig place-year. When using microbiological activity to produce the organic acids, the total annual costs for milled wheat are $29.82 CAN and $15.04 CAN for heated potato starch.