Planning, project management, consultancy, survey
and analysis in coastal and offshore sectors

 

SEDIMENT TESTING

EMU's Particle Size Analysis (PSA) laboratory tests marine and freshwater sediments, effluents and sludge bio-products.Our participation in NMBAQC, LDPTS and LEAP external proficiency schemes demonstrate consistent quality in testing. See Quality Assurance The particle size distribution of a product can be of paramount importance in determining its physical properties and stability.

Services include:


Dry Sieving Method
This method covers the quantitative determination of the particle size distribution in cohesionless sediment down to the fine sand size (63mm - 63µm).Dry sieving is undertaken either following wet sieving or on its own if wet sieving is not required. The dry sieving method is UKAS accredited, and is carried out in accordance with EMU in-house procedures based on BS1377-1&2: 1990.

Dry Sieving Dry Sieving

Wet Sieving Method for Laser Diffraction
This method covers the quantitative determination of the particle size distribution in an essentially cohesionless sample down to the fine sand and clay/silt size. The procedure involves preparation of a sample by wet sieving to remove the fine sand and silt sized particles of <63µm. Samples which are subsequently found to contain >5% fine material (particles of <63¼m diameter) are then subjected to further analysis via laser diffraction to determine the proportion and distribution of the silt/clay components of <63¼m. The wet sieving method is carried out in accordance with EMU in-house procedures based on BS1377-1&2: 1990.

Wet Sieving Wet Sieving West Sieving


Laser DiffractionLaser Diffraction
The determination of particle size distribution by laser diffraction is carried out in accordance with EMU in-house procedures using a Malvern Microsizer Laser Diffractor. Laser diffraction determines particle distribution, based on the principal of laser ensemble light scattering and is equivalent to sedimentation by the pipette method (based on BS1377-2: 1990).

  • Measurement range of 0.313µm - 301µm at 0.5 phi intervals
  • Results are volume based
  • Results are expressed in terms of equivalent spheres
  • All parameters are derived from fundamental distributions
Test results can be integrated with particle size distribution results for sample fractions >63µm (derived by dry sieving) to provide distribution for the full size ranges. The Malvern Microsizer can analyse particles in the range 0.313µm - 301µm at 0.5 phi intervals; therefore, where determination of distribution is required in this size range only (i.e. liquid samples), analysis can be carried out without the preliminary sample preparation.


Soundness Testing of Biological Filter Bed Media
The sodium sulphate soundness test (BS1438: 2004) is used to determine the probable durability of new filter media, for which there are standard criteria. The test can also be used to analyse the condition of existing media.

Pre-Treatment of Organic Matter
Hydrogen peroxide pre-treatment of organic matter can be stipulated by the client as part of the analysis procedure. The process is normally undertaken when organic matter is present in the sediment in significant quantity (0.5% or more). The method is based on BS1377-3: 1990

imageOrganic content / Loss on Ignition
Loss on Ignition (LOI) determines the proportion by mass that is lost from the sediment by ignition at a specific temperature using an electric muffle furnace capable of maintaining temperatures of >600°C. The mass loss on ignition is related to the organic content of certain sediments, such as sand which contains little or no clay, or chalky material, peats and organic clays which may contain more than 10% organic matter. the method based on BS1377-3: 1990

Total Suspended Sediment
The determination of the total weight of suspended sediment in: fresh water, saline water and effluent.UKAS accredited - method based on HMSO Methods 1980.

Freeze drying of sediments and shellfish tissue for further analysis as required by the client.

Statistical Representation of Results
PSA data can be displayed in statistical formats using both moment and graphic techniques including the presentation of mean, median, sorting, skewness and kurtosis values.

Quality Assurance - also see Quality Assurance

  • All Particle Size Analysis is undertaken in accordance with EMU in-house procedures based on those published in BS1377 Parts 1-3: 1990.
  • Analysis for the determination of particle size is carried out following UKAS accredited procedures as documented in EMU in-house method statements. All in-house procedures are rigorously audited both internally and externally by UKAS and BSi.
  • Quality control procedures are employed and documented throughout all stages of analysis to ensure confidence and traceability of data. All equipment used in analysis is regularly monitored and calibrated for acceptable quality. All staff involved in particle size analysis have received appropriate and documented training.Â
  • EMU also participates in the Laser Diffraction Proficiency Testing Scheme (LDPTS), the National Marine Biological Analytical Quality Control Scheme (NMBAQC) and the Laboratory Environmental Analysis Proficiency Scheme (LEAP) helping us to achieve an even higher standard of analysis for our clients.

Deep knowledge in shallow seas

Copyright © Emu Limited, Company Registration No.3469947, VAT No. 704 4481 52
Registered Address: 1 Mill Court, The Sawmills, Durley, Southampton, Hampshire, SO32 2EJ