Atmospheric Dispersion Stack Evaluation

Purpose

• To determine the operating efficiency of an atmospheric dispersion stack in terms of resultant Maximum Ground Level Concentration of dispersed contaminants
• To ensure system regulatory compliance and / or to ensure maximum
  odor unit reduction at receptor sites

Procedure

• Measure gas volume, temperature, pressure, humidity, perform primary compositional analysis
• Speciate and quantify residual contaminants to be dispersed by discharge stack, calculate mass emission rates
• Examine the potential for significant variances in major dispersion parameters including stack flow rate, gas condition, mass emission rates etc. as they impact on atmospheric dispersion
• Evaluate stack physical dimensions and discharge conditions for building downwash caused by adjacent structures, stack tip downwash, and other influences that may adversely affect plume rise characteristics
• Perform computer dispersion modeling using Screen3, ISC ST3, or other appropriate regulatory model to estimate Maximum GLC of regulated and unregulated constituents as required

Report

• Provide a written report outlining the pertinent physical and effective parameters of the existing discharge stack.
• Summarize in table form the stack modeling parameters and mass
  emission rates for each constituent identified
• Provide computer model output files for each modeled parameter,
  complete with estimates of Maximum GLC and compare maximums
  with regulatory limits in table form
• Make specific recommendations for improvement in system design as warranted