PeCOD® Case Study #02
Industrial Wastewater Treatment
Industrial wastewater treatment facilities are integral parts of protecting local ecosystems by removing contaminants from water generated during industrial processes. Since these facilities discharge large amounts of water, they must meet municipal biochemical oxygen demand (BOD) standards. Industries including automotive, manufacturing, steel, chemical, and dairy often produce a significant amount of wastewater. Therefore, it must be treated and tested before discharge.
BOD indicates how much oxygen bacteria need to break down organic material in water. Since high levels of organic material can harm aquatic life, BOD is one of the indicators of water quality. Monitoring BOD ensures that water discharged into the environment does not contain large amounts of organic matter. However, BOD testing takes five days to complete, delaying real-time monitoring. During this period, wastewater can accumulate and make the process inconvenient.
As a result, alternatives to BOD are available, including chemical oxygen demand testing using dichromate (CODCr). Analysts can assess organic contamination more quickly with CODCr compared to BOD, completing the process in just three hours. Despite its speed advantage, the CODCr exposes analysts to harmful chemicals, namely dichromate, mercury, and concentrated acid. The CODCr process also requires expensive hazardous waste removal.
In response to these challenges, MANTECH offers a rapid, safer alternative. MANTECH’s PeCOD® analyzer obtains 10-minute BOD/COD results, without the use of hazardous reagents.
Clean Harbors
Clean Harbors offers a range of services to handle hazardous and non-hazardous waste, recycling, reclamation, and remediation for various industries across North America. The company’s plant in Guelph, Ontario utilizes highly refined, chemical precipitation processes, which remove heavy metals, suspended solids, and organics to generate safe effluent. It is essential that their product meets the municipal discharge requirements to ensure that the environment is protected.
Case Study
A study was conducted to assess the correlation of PeCOD, CODCr, and BOD5 at Clean Harbors Guelph in 2016. The objective of this study was to determine if a correlation exists between PeCOD® COD and traditional methods. The soluble COD was analyzed by the PeCOD® COD method and compared against the dichromate COD (CODCr) and BOD5 methods.
Results
The results below are from a single Clean Harbors treatment plant in Guelph, servicing industries including automotive, manufacturing, primary steel, chemical, and dairy facilities. Samples were prepared by centrifugation to settle solids then mixed in a 1:49 ratio with RED range PeCOD® electrolyte. The results indicated a strong correlation between PeCOD® COD and CODCr for incoming hauled wastewater (Figure 1). Similarly, the results from treated wastewater samples taken from various industries demonstrated a strong correlation between PeCOD® COD and BOD5 methods (Figure 2).
Figure 1: A scatterplot demonstrating a strong correlation between PeCOD® COD and CODCr for incoming hauled wastewater from a variety of industries.
Outcome
Upon completion of the study, Clean Harbors invested in the PeCOD® COD Analyzer, complete with autosampler, immediately putting it into production and replacing the CODCr method. The key advantage for Clean Harbors in adopting the PeCOD® COD Technology was the speed of the test. For example, the wastewater facility can obtain critical information on incoming loads within 10 minutes, allowing for quick decision making and efficient treatment.
Prior to unloading, the analyst obtains a CODCr measurement using the PeCOD®. If the result exceeds the acceptable limit, the analyst immediately diverts the truck to an incinerating plant. However, because the CODCr method takes approximately two hours to produce results, the truck would have already unloaded the wastewater and left the facility. Avoiding this time delay eliminates the requirement for subsequent storage and hauling costs.
Furthermore, incoming wastewater that meets plant sewer discharge limits can be quickly discharged, reducing chemical and energy costs. Additionally, the PeCOD® provides a reliable estimate of BOD, which is required for compliance with municipal standards. Historically, Clean Harbors Guelph received BOD results eight days after sampling. Now, the facility receives a daily real-time BOD estimate, ensuring peace of mind with regards to their treated discharge effluent.
Following the success of the PeCOD® at the Guelph plant, Clean Harbors successfully implemented the PeCOD at their Bristol, Connecticut facility in 2023.
