WEFTEC17 proved to be one of the best ones yet for LuminUltra! Here are top three questions we were asked:
1. Can you measure ATP in anaerobic systems?
Yes, ATP can be measured in aerobic, anoxic and anaerobic systems. ATP is a measure of total biomass and is not specific to any one functional metabolic group. The only thing that changes is the expected range of ATP values. For aerobic systems, such as an aeration tank or bioreactor, a healthy system would be expected to have an active biomass ratio, ABR, (which represents the percentage of the suspended solids that are biologically active) of >40%. For an anaerobic system, the ABR for a healthy system would be expected to be much lower (>5%). This is due to two factors: anaerobes typically grow at a slower rate relative to aerobes (generally 10%), and because anaerobic systems typically have a significantly higher solids loading rate.
2. Can ATP measure for specific species?
No, ATP is a bulk measurement. LuminUltra’s 2nd Generation ATP can differentiate between living and dead biomass, but it cannot identify specific species. There are several other options to identify specific species such as metagenomics, which uses DNA sequencing to identify the types of organisms in the sample. ATP can be used as a ‘smoke alarm’ that can quickly detect a shift in the active biomass and trigger a more specific test, such as a metagenomics profile. These styles of tests provide a considerable amount of data, but can take days to weeks for results and as such should be relied upon less frequently.
3. How do you do a wastewater ATP test?
There are three steps to a standard LuminUltra QG21W test: calibration, analysis for total ATP (tATP) and analysis for dissolved ATP (dATP). Calibration is important as it allows the relative light units (RLU) from the luminometer to be converted to an actual quantity of ATP (i.e. ng ATP/mL). To measure tATP, a small amount (1mL) of sample is added to a lysing agent which breaks biological cells open, exposing their contents. The lysed solution is then added to a dilution tube to remove any interferences. After dilution, the solution is combined with a luminescent enzyme (LuminaseW) and the light given off is measured by the luminometer. The dATP measurement is very similar except no lysing agent is used as dATP measures dissolved or extracellular ATP only. Once both tATP and dATP have been measured, the active biomass (or cellular ATP, cATP), can be calculated as the difference between tATP and dATP. The entire test takes approximately 5 minutes.
Hear Dr. Jordan Schmidt – LuminUltra’s resident wastewater expert – discussing water infrastructure demands, sludge bulking, and the need for knowledge transfer in the industry at WEFTEC17. Check out below.