There have been studied 10 different metalworking fluids of emulsion, semi-synthetic and synthetic types, according to their availability to biodegradation. As the microbial inoculum was used the activated sludge becoming from the sewage treatment plant treating the municipal sewage waste waters and obtained results were compared. It was find out that only one of tested fluids has the biodegradability lower than 20 % after 21 days of cultivation. Six samples have the biodegradations rate in the range 39-55 % and two had their biodegradability above 60 %. As the most biodegradable tested samples of metalworking fluids were evaluated synthetics with their biodegradability above 44 %. Two of them achieved the biodegradability 50-55% and one reached the level 68 %. Than followemulsions; their biodegradabilitywas 39-40% in three cases of four tested samples. One sample achieved the biodegradations rate 65%, but it has to be note that this sample had lower addition of organic carbon input – this was 141 mg C in opposite 252-281 mgC. One sample of semi-synthetics has the lowest reached ultimate biodegradation – 19.5%.

Full text: IJEIR_1841_Final.pdf