A study to determine the effect of three wastewater concentrations loading to a biological pretreatment facility was undertaken. The possibility of nitrification inhibition was of concern with each of the candidates’ three wastewaters. Additionally, cost and discharge problems would be experienced if a failure in ammonia removal occurred. A secondary element of the study was to establish a protocol for the respirometry of new waste streams as a means of selecting optimum process wastewater to treat internally and to streamline or reduce costs relating to manufacturing operations.

This data table illuminates the failure in nitrification. Note that ammonia levels were not significantly changed between the before and after respirometric categories. The rate biograph here confirms that in the area of the expected nitrification “shoulder,” no visible nitrification respiration was observed.

Subsequent process changes and toxicity testing verification indicated conclusively the relative and total effects of the waste streams to the biological treatment system. Changes made in the wastewater generation point improved the bioavailablity of the waste, improving treatment time thereby reducing production costs.

A confirmatory respirometric and analytical study was performed after the process changes and ammonia to nitrate conversion improved to more than 97%. The company benefited in knowing the optimum-loading rate and response time for these wastewaters in their pretreatment train allowing an increase in throughput to discharge, thereby reducing costs and positively affecting the waste cost to product ratio.