Soluble, semivolatile phenol and nitrogen compounds in milk-processing wastewaters

Abstract

Potable water is an essential and major input in processing our food supplies, and the continued growth in food manufacturing is placing increased pressure on this limited resource. Recycling and reuse of factory wastewater can lessen potable water use but requires a detailed understanding of wastewater properties. This study uses solid-phase extraction techniques with gas chromatography-mass spectrometry analysis to investigate trace-level semivolatile organic species in various waste and reference waters associated with the Burra Foods milk-processing plant located in Southeastern Australia. Our focus was on contaminants containing phenolic and heterocyclic nitrogen functional groups, which, because of their toxicity and persistence, may limit options for water recycling and reuse. Effluent from the wastewater treatment plant of the factory showed both the highest soluble carbon burden (47 mg/kg) and concentrations of target compounds. The target species found in these effluents included methyl phenol (13 mg/kg), hydroxy indole (9.8 mg/kg), synthetic tolyltriazoles (5.1 mg/kg) and alkyl phenol ethoxylates (0.2 mg/kg). Given the environmental stability of the tolyltriazoles, they may act as chemical markers where these effluents are used for purposes such as irrigation. Milk evaporator condensate waters, in contrast to the effluent, contained very few target species, with only low levels of pyrrolidine and piperidine derivatives such as ethylglutarimide (450 mug/L) detected. Although there were fewer target microcontaminants overall in the potable and creek reference waters, these samples had characteristic profiles. The potable water analysis revealed hydroxy cineole (2.1 microg/L) and the creek analysis revealed dichlorohydroxyacetophenone (0.3 microg/L), which were not detected in other waters. The compounds found in the wastewaters are likely to have been derived from milk or synthetic chemicals used in factory operations. The presence of nitrogen compounds in all the different milk-processing waters suggest their likely source was milk, probably milk phosphoproteins subjected to thermal, chemical, or microbial degradation. Our benign results for the condensates suggest it may be possible to substitute condensate for potable water with minimal pretreatment, both within the plant and in other applications, such as irrigation of recreation turf.

Matrix effects of milk, dairy factory wastewater and soil water on the determination of disinfection by‐products and para‐cresol using solid‐phase microextraction

“…; Verheyen et al . ). One milk, one milliQ, three wastewater and three soil water sample matrices were tested.…”

“…; Verheyen et al . ; Heaven et al . ) suggested that dairy matrices contain compounds like fatty acids or caseins that may affect the analyses of compounds such as HAAMe and para‐ cresol through, for example, fouling of the SPME fibre.…”

“…In this study, we investigated how dairy-related matrices affected the effectiveness of SPME for the detection of para-cresol and derivatised HAA [haloacetic acid methyl esters, HAAMe, used due to HAA degrading to halomethyl compounds in the GC-MS (Cardador et al 2008)]. Previous studies (Moate et al 2007;Verheyen et al 2009;Heaven et al 2011) suggested that dairy matrices contain compounds like fatty acids or caseins that may affect the analyses of compounds such as HAAMe and para-cresol through, for example, fouling of the SPME fibre.…”

Dairy Factory Wastewaters, Their Use on Land and Possible Environmental Impacts - A Mini Review

“…The typical characteristics of wastewaters from various types of dairy facilities are presented in Table 1. Condensate collected from the evaporation of milk or whey is one of the cleanest wastewaters although it may contain volatile organic components [10] and possibly liquid droplets of milk or whey entrained into the vapour stream from the evaporators.…”

Analysis and in situ characterization of activated sludge communities capable of benzotriazole biodegradation

“…4-and 5-TTri are commercially available as tolyltriazole mixture (TTri) that is widely used in metal finishing and as corrosion protection in cooling systems [1,2]. Among other applications, these three benzotriazole species are mainly used as anticorrosives in aircraft deicing or breaking fluids [3], in household dishwashing detergents for silver protection [4], and as UV stabilizers [5,6].…”