Reduction of acrylonitrile in wastewater from the production of ABS plastic

A process for reducing the volatilization of hydrocarbon monomers from a wastewater stream from a polymerization stream, said process comprising the steps of:

• a) addition of an oxygenated activated sludge to the stream to reduce the level of hydrocarbon monomers in said stream by aerobic digestion prior to primary clarification of said stream;
• b) primary clarification of said stream;
• c) aeration of said stream;
• and
• d) secondary clarification of said stream to produce a treated effluent and settled activated sludge, and
• e) oxygenating said activated sludge and recycling said oxygenated activated sludge to the addition step a).

A process for reducing the volatilization of residual hydrocarbon monomers from polymerization wastewater streams, said process comprising the steps of:

• a) addition of an oxygenated activated sludge to said polymerization wastewater stream to reduce the level of hydrocarbon monomers by aerobic digestion,
• b) primary clarification of said polymerization waste water stream after the addition of said activated sludge, said primary clarification step involving separation of steam into a primary clarifier sludge and a primary clarifier water effluent, said primary clarifier water effluent having a biological oxygen demand of greater than 400 mg/l,
• c) aeration of said water effluent stream in the presence of additional activated sludge to produce an aerated effluent stream having a biological oxygen demand of a level less than 10 mg/l,
• d) secondary clarification of said aerated effluent stream to produce a treated effluent and settled activated sludge, and
• e) oxygenating said activated sludge and recycling said oxygenated activated sludge to the addition step a).