Salinity tolerance for biological treatment
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This post was last edited by wyf600 on 2015-6-19 at 19:08. I would like to ask everyone what the maximum salt content that biological treatment methods (anaerobic and aerobic) can tolerate is. Please share your experiences, whether it relates to salt content or conductivity. I checked some literature; the conductivity range for anaerobic conditions is 8–20 ms/cm. I also recall that it can reach up to 30 ms/cm in anaerobic environments, but I can’t find any source for this information now.
Conductivity is greatly affected by temperature, impurities, and mixed solutions of various salts; generally, ion concentration and salt content are more accurate indicators. It is relatively accurate for pure or single-component solutions, but temperature compensation is required.
From the perspective of salt concentration, generally, microorganisms are less tolerant to divalent salts than to monovalent salts, and higher-valent salts are more toxic. We conducted an experiment on the salt tolerance of aerobic bacteria, using sodium sulfate and sodium chloride as salts, with sodium sulfate accounting for about 70% ； Below 1.3% (13,000 mg/L), it has virtually no effect on aerobic bacteria ； At 1.5%, changes begin to occur in the community of aerobic bacteria, affecting the operation of the activated sludge and resulting in a significant decline in operational efficiency ； At 1.8%, inhibition of protozoa was evident; metazoans disappeared, some sessile protozoa vanished, and the operational efficiency dropped significantly.
We generally keep the salt content below 5000 mg/l!
It seems that using conductivity is still more convenient, as there are online instruments that allow for temperature compensation. I don’t know what the conductivity will be.
Conductivity is greatly affected by temperature, impurities, and mixed solutions of various salts; generally, ion concentration and salt content are more accurate indicators. It is relatively accurate for pure or single-component solutions, but temperature compensation is required. From the perspective of salt concentration, generally, microorganisms are less tolerant to divalent salts than to monovalent salts, and higher-valent salts are more toxic.
It is generally measured in percentages, and the salt content in wastewater that can be treated by current biochemical technologies is usually below 3%. We specialize in the research of biochemical technologies for high-salinity wastewater treatment. We are now capable of treating wastewater with a salt concentration of less than 8%, although the HRT is longer than that in conventional biochemical treatment processes, and the COD level of the treated water is somewhat higher