Orange County Sanitation District (OCSD) commissioned Malcolm Pirnie, a consulting engineering firm, to assess options for cleaning and repair of a large gravity sewer running along Huntington Beach, CA. The sewer had become partially filled with beach sand that had become polluted from illegal dumping and from other sources.

The use of a mobile analytical laboratory was an integral part of the team assembled to answer the question: How polluted is it and what options for cleaning are available?


OCSD has a zero odor policy (no odor leaving the collection system or treatment plant). Meeting that requirement during the sewer system sample gathering process required several additional expensive steps.

To make this event even more convenient for the neighborhood, the sampling was done at night to minimize interference with vehicular traffic at manhole locations in public streets. Sampling at night also allowed access into the sewer when liquid flow was minimal.

Because the sampling was such an elaborate and expensive process, there was a need to ensure adequate samples were taken in each section of the sewer while it was accessible, eliminating the cost of a second entry setup procedure. Malcolm Pirnie solved this problem by utilizing a mobile laboratory.

This on site laboratory analyzed liquid and soil samples gathered from the sewer while the sewer was open. In this way when areas of contamination were identified, additional soil samples could be gathered in that vicinity.

The accurate characterization of the solids in this sewer was only possible because of this immediate quantitative and qualitative feedback provided by the mobile laboratory.

This technician is entering the sewer to collect samples. He will not be this clean on the way out.
This support team is monitoring a technician in the sewer. As part of the safety procedure, a second technician (holding the ladder) is geared up and ready to enter the confined space if necessary.
The photos above and below are views of a mobile laboratory. The laboratory is capable of evaluating the presence of organic, sulfur and other compounds to the part per billion / part per million concentration ranges and providing results in about 30 minutes! For a laboratory - that is absolutely amazing! Conventional lab results take 10-14 days on normal turnaround and of expedited, can cost 2x or more the standard price.