the temperature of slaughterhouse effluent appears to vary significantly worldwide. in europe, it is frequently cool (20'C), in contrast to australian effluent, which is routinely 30-35'C, but can be even hotter in subtropical areas. this can be a significant issue in the choice and economics of wastewater treatment operations (i.e. high-rate anaerobic systems; nitrificaion), since biological systems typically perform considerably faster at higher temperatures (37'C) ; conversely, fat emulsification at the hotter temperatures causes substantial difficulties, especially in intensive-treatment systems, such as activated-sludge plants.