A Look at the Lab: Turning Muck into Gold

SESL Australia

SESL’s in-house lab is constantly striving to achieve reliable high quality results for our clients and aims to find the most appropriate methods of testing and analysis for any given sample or purpose. A recent challenge involved a particularly fishy sample that presented a number of physical and chemical complexities in analysis. The sample itself was a nasty waste product from a processing stage in the Food industry; think a sludgy 50/50 blend of rotten soy sauce and old seaweed. The sample was being tested in order to determine its suitability for disposal/recycle/repurposing through an assessment of physical and chemical properties such as salinity, nutrient and contaminant levels.

Analysis of a sample of this nature requires a number of considerations to be made when selecting the range and type of testing that is to be utilised. These decisions are informed by the nature of the sample and the objectives of the client. The following are standard for SESL lab’s approach to unusual samples:

  1. Recognising the analytical objectives of the client and their practical application.
  2. Dealing with the safe preparation and handling of unusual samples
  3. Selection of an adequate testing regime based on the physical sample type.
  4. Identifying and compensating for complex sample matrix throughout analysis.
  5. Ensuring an appropriate analytical finish is selected to compensate for sample matrix and type.

Solid digested ( L) - Liquid Filtrate (R)

The sample was originally prepared and tested as separate liquid and solid components. It was filtered and diluted in order to adequately test for the soluble content of salts and nutrients whilst the solid component was dried, to establish moisture content prior to acid digestion to determine the total acid soluble composition of the solid component. The high salinity of the sample alongside high concentrations of other elements required specific attention to be paid in ensuring these did not interfere with other analytes and produce any negative or positive bias. The results produced were satisfactory in meeting the majority of the client’s expectations. However, it was clear that the original testing was not adequately mirroring the source material as it was processed and handled in reality. The process in question was being designed to allow the solids and liquid components to settle via sedimentation and flocculation before being separated and treated individually. Thus the sample was taken back to the drawing board with the original results and approach alongside the processing reality in mind. The adjusted method was to make use of centrifuging to rapidly replicate a longer settling time. The sample was then separated via decanting and the liquid was tested to confirm prior results. The solid component was then tested for soluble and digested analytes without drying to reflect the distinct product of the settling/centrifuging process alongside a new moisture content data. The final stages of testing were successful and provided the necessary information to allow our client to move forward with their planning and process design.

 The success of this project was founded on the expertise and skill built into the SESL team which allows for a nuanced and client specific approach to be adopted for every sample. No matter the muck, SESL is ready to help convert waste streams of any and every kind into gold.

Article written by SESL Australia Laboratory technician Dominic D’Adam