Question 5 of 19: Steps in Conducting an Industrial Waste Survey

Question 5: Steps in Conducting an Industrial Waste Survey (10 marks)

Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.

An industrial waste survey is the systematic characterization of a facility's wastewater sources, flows and strengths that underpins any treatment, pretreatment or sewer-use-bylaw decision. The steps, in the order they are normally carried out, are:

1. Review the facility's process description, flow diagrams, raw materials and production schedule to identify every point where water contacts the process (a desktop review before any field work).
2. Conduct a plant walk-through with operations staff to confirm actual practice against the documented process, and to locate every discharge point (floor drains, process outfalls, cooling water, stormwater).
3. Prepare a water balance / mass balance for the facility, tracking intake water through each unit operation to each discharge point.
4. Design a sampling and monitoring program — select sampling locations (each significant source and the combined outfall), sampling method (grab vs. flow-proportional composite) and frequency, matched to the expected variability of each source.
5. Measure flow at each sampling point (continuous flow metering where practical) concurrently with sample collection so mass loads, not just concentrations, can be computed.
6. Analyze samples for the parameters relevant to the industry — at minimum BOD₅/COD, SS, pH, temperature, oil & grease, and any process-specific parameter (metals, cyanide, phenols) known or suspected to be present.
7. Characterize temporal variability — production-shift patterns, batch dumps, seasonal operation — since a single-day sample can badly misrepresent a batch or seasonal process.
8. Cross-check the survey's flow and load totals against water-purchase/metering records and production records as an independent quality check on the sampling program.
9. Identify opportunities for source control, segregation of clean and contaminated streams, water reuse/recycling, or process modification that could reduce the load requiring treatment.
10. Compile the survey report: waste sources, flows, loads, variability, applicable discharge limits, and recommendations for pretreatment or connection to the municipal system.