Treatment of waste water, esp from dye houses - with bulk of surfactants being removed as foam and mixed after standing with recycled coagulated sludge

摘要

For its purificn. dye house waste water contg. pigments and a large amt. of surfactants is treated by first being agitated thoroughly with compressed air to build up a foam which overflows with the bulk of the surfactants into a settling tank. The liq. freed from the foam is treated with coagulating and pH-adjusting agents and clarified, the sedimented sludge then being mixed with the foam returned to liq. form and vigorously agitated to exploit its residual coagulant qualities. The process is repeated, the coagulated sludge being continuously recycled into liq. derived from the foam, until its value is completely exhausted.