Thank you to everyone who has responded to my inquiry both on and off-line. Feedback indicates a range of strategies for addressing the issue of acid (or chemical)resistant piping and the need for acid neutralization tanks for laboratory buildings..  These include:

1. Eliminate Separate Waste Systems - some schools have eliminated the design of separate systems completely and thus there is no requirement for acid neutralization tanks. 
2. Separate systems but no acid neutralization tank - design separate systems with chemical resistant piping as a precaution to protect the building systems in the event of spills or incidental discharge of small quantities of chemicals. In these cases school policy prohibiting drain disposal of corrosive waste (or other chemicals) appears to be the key to getting approval from the local POTW or code enforcement authority. 
3. PH Monitoring  - In some instances, local POTWs have required monitoring to demonstrate that the discharged waste water meets pretreatment standards. This is a challenge for lab waste system which may have intermittent flow.

The decision of which option is typically dictated by the local authority having jurisdiction (code enforcement, local POTW or building commission) interpretation of the IPC.  In addition, the schools must decide the appropriate strategy for their purposes.

 

For those of you with an interest, I was able to locate the pH study of laboratory wastewater.  Following is the citation and abstract:

Robert C. Klein, Research laboratory wastewater neutralization systems, In Journal of Chemical Health and Safety, Volume 13, Issue 2, 2006, Pages 15-18, ISSN 1871-5532, https://doi.org/10.1016/j.chs.2005.02.004.

Abstract:  Laboratory wastewater neutralization systems are increasingly being specified for academic teaching and research buildings by many environmental consultants and design engineers. While real efforts to improve the quality of wastewater are generally positive, simply installing such systems without regard to their operational setting increases capital costs, significantly increases equipment service and maintenance needs and expenses, and can potentially generate higher environmental, health, and safety risks from chemical handling exposures, spills, leaks, or uncontrolled releases to sewer. In response to concerns about possible neutralization system needs for a new chemistry building at Yale University, continuous pH measurements were collected from several laboratory-intensive teaching and research buildings over periods of time ranging from 22 to 37 days in each building. Real-time pH measurements were collected in the main branch of the laboratory wastewater drain line in each building just prior to junction with house sanitary lines. Laboratory wastewaters averaged 6.5 pH units over the aggregate datalogged period of 82 days during the academic year. While more extreme pH values were occasionally observed, values less than about 5 or greater than about 9 were exceedingly rare, and accounted for fewer than 15minutes of the laboratory wastewater discharged during the nearly 3 months of continuous sampling. Since the measurements were all collected at points just prior to mixing with building sanitary effluent, significant additional wastewater dilution occurred prior to final discharge to sewer. Based upon these results and a review of the potential health and safety hazards associated with neutralization systems, their installation – at least in academic teaching and research laboratories – is generally unnecessary.

 

Best,

 

Steve

 

 

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