General Motors of Canada
HH Angus’ work on GM Paint Shop process waste system involved combining the process waste flow from two paint shops into a common process gravity sewer system leading to the onsite waste treatment plant. The calculated maximum combined flow was, in fact, greater than the capacity of the existing gravity sewer (1900 USGPM), which necessitated flow control measures to meter the flows. Since the flows from both plants fluctuated with shift loads, storage head tanks were installed to allow the metered flow to function effectively.
One of the challenges was the difference in flow velocity. The new paint shop process water was being pumped, while the process waste from the existing paint shop was gravity flow. In order to discharge the pressure, velocity and energy from the pumped process waste, we designed a two- compartment underground concrete quiescent chamber that was installed between the pumped and gravity sewers. This allowed the two waste streams to mix and flow to the waste treatment plant much more effectively.