Wastewaters are increasingly being reused in public spaces to supplant the use of potable water. In this study we investigated possible trace organic contaminants in wastewater from a dairy factory applied to a recreation reserve. Samples were taken of recycled dairy factory wastewater used to irrigate the reserve and from the subsurface drainage system after irrigation and after rainfall. Using gas chromatography–mass spectrometry, it was found that irrigation drainage mostly contained different compounds to those in rainfall drainage. This drainage water was found to contain residues of three agrochemicals (dicamba, 0.4 ± 0.07
Wastewater from a dairy processor is being reused and recycled both within the plant and for irrigation. Flash pyrolysis GC–MS was used to examine nitrogen and phenol containing compounds (M.W. = 35 to 450 g/mol) in the particulate fraction of the milk condensate, combined clean wastewater and aerobic bioreactor effluent. For comparison, the particulates were also prepared for standard GC–MS analyses using conventional solvent extraction methods. Compounds detected by pyrolysis GC–MS were found mostly in the bioreactor with the amino acid arginine (220 mg/kg) and the amino acid derivative 1-methyl-5-oxo-L-proline methyl ester (130 mg/kg) found at the highest concentrations. In comparison, sterols detected in the effluent were found at higher concentrations when using solvent extraction indicating some degradation with pyrolysis GC–MS. However, with few exceptions, particulates were generally found not to act as passive collectors capable of concentrating less water soluble chemicals.