Which test can help estimate organics, BOD, aerobic digestion efficiency, and microorganism population?

The choice of MLVSS, or Mixed Liquor Volatile Suspended Solids, is the most appropriate because it directly measures the concentration of organic material present in the mixed liquor of an activated sludge system. This measurement is crucial for estimating the amount of organics in the wastewater, as MLVSS comprises the volatile fraction of the suspended solids, primarily consisting of microorganisms and their metabolic byproducts.

MLVSS is particularly useful in understanding aerobic digestion efficiency, as it indicates the biomass available for treating wastewater. The value obtained helps operators to monitor and optimize the conditions within the aeration tanks, which can lead to improved treatment performance. A higher MLVSS usually corresponds to a more substantial population of microorganisms capable of breaking down organic matter, thus enhancing the biological treatment process.

In comparison, other tests like COD (Chemical Oxygen Demand) measure the total oxygen demand from both biodegradable and non-biodegradable organics, while TS (Total Solids) assesses the total concentration of all solids, including both volatile (organic) and fixed (inorganic) solids. TKN (Total Kjeldahl Nitrogen) measures total nitrogen in the form of organic nitrogen and ammonia but does not provide a direct indication of the organic load or microbial activity.