Laboratory studies of sediments of sewage treatment plants are an important stage for determining their composition, properties and potential danger to the environment and human health. These studies help in choosing optimal processing methods, utilization or disposal of sediments.
The main goals of laboratory studies of sediments:
- Determination of physical and chemical properties: Moisture content, ashness, granulometric composition, density, pH, redox potential.
- Determination of organic composition: The content of organic substances, biological and chemical consumption of oxygen (BSK, HSK), fat content, proteins, Carbohydrates, specific organic pollutants (petroleum products, phenols, COUPLE, pesticides etc).
- Determination of the content of heavy metals and other inorganic pollutants: Lead, cadmium, mercury, chromium, nickel, arsenic, fluorides, sulfates, etc.
- Microbiological studies: Determination of the total number of microorganisms, pathogenic bacteria, helminths, viruses.
- Radiological studies: Determination of the content of radionuclides.
- Toxicological studies: Determination of acute and chronic toxicity of sediments.
Basic methods of laboratory research:
- Physical methods: Determination of humidity (drying), ash (burning), granulometric composition (sieve analysis), density (pycnometry).
- Chemical methods: Titrimetry, spectrophotometry, chromatography (gas and liquid), Atomic-absorption spectrometry, mass spectrometry, X-ray fluorescence analysis.
- Microbiological methods: Cultivation on nutrient media, microscopy, PCR diagnostics.
- Radiological methods: Gamma spectrometry, beta radiometry, alpha spectrometry.
- Toxicological methods: Biotesting using test organisms (daphnia, infusorium, plants, etc).
The results of laboratory research are the basis for the development of effective and safe technologies for processing and utilization of industrial sludge, as well as to control their impact on the environment.