This report describes the results of the research into the effect of anaerobic digestion on the orthophosphate content in dairy manure. On different dairy farms with a manure digester and separators samples were taken from the manure, digestate, liquid fraction, thick fraction and analyzed on the content of orthophosphate. Furthermore, the orthophosphate was extracted from the liquid fraction with calcium hydroxide. The orthophosphate content decreases as a result of anaerobic digestion. The orthophosphate content was on average 34 mg/kg in the digestate and was lower than in the incoming manure with average content of 75 mg/kg.

This report describes the results of the research into the phosphate forms and the potential of recovery of phosphate from dairy manure. On different dairy farms with different types of manure separators, slurry robots and scrapers samples were taken from the manure, liquid fraction, thick fraction and/or faeces and analyzed on the content of different phosphate forms. Furthermore calcium hydroxide was added to the liquid fraction to separate the orthophosphate with the sediment and are the thick fractions diluted and acidified to pH 6 and 5 to determine the amount of phosphate being released as orthophosphate. On the basis of these analysis is the potential for recovery of phosphate determined.

This report describes the results of the research into the orthophosphate content in (separated) pig manure and faeces. Manure from several different animal categories was collected and separated with a screw press or a centrifuge, and samples were collected of the manure and fractions and analyzed on the content of available orthophosphate and total phosphate. Furthermore, the orthophosphate was extracted from the liquid fractions of the centrifuge with calcium hydroxide. The orthophosphate contents were low with the exception of the faeces of piglets and finisher pigs fed dry feed which had a content of around 2459 mg/kg.

Indikken van dunne mestvloeistof in een indamper/luchtwasser combinatie, waarbij gebruik wordt gemaakt van geventileerde stallucht, kan een aanzienlijke volumereductie opleveren zonder dat dit ten koste gaat van de emissiereducerende werking van de luchtwasser voor wat betreft ammoniak en geur. Op een zeugenbedrijf kan het mestvolume minimaal met een derde worden gereduceerd. De kosten van de volumereductie bedragen ongeveer 12 euro per m3.