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What can you do with Microbial Community Analysis data

4/15/2019

A total microbial census of MLSS using advanced 16s rRNA sequencing is interesting, but what is the practical application of this big pile of data. As with most new testing, I often get the "what does this mean" question. So, I will highlight a few ways we are using the data.

Track populations of Ammonia Oxidizing Bacteria (AOB) & Nitrite Oxidizing bacteria (NOB). We all know that the AOB & NOB cultures are both slow growing and susceptible to upset. Genetic testing can monitor these populations and give early warning of population increase or decline.
Find your true position on the growth curve - MCA data gives information on microbial diversity and if k-rate or r-rate strategists are dominating the biomass. This allows for great information that looks at the microbial populations rather than calculations such as F/M or MCRT.
Systems with bulking tendencies - either filamentous or non-filamentous - have used MCA testing to monitor both filament and viscous bulking form microbes. The test helps guide operators before bulking effects effluent quality.
Rapid information about changes in biomass makeup due to operational changes. Changing influent makeup, MCRT, aeration, or any other major control creates a change in biomass. MCA testing gives information about what is changing and how it will impact effluent quality.

The list above is how we are currently using MCA test data. By running time series tests on individual systems and comparing with other similar systems, we are able to show what is the normal biomass makeup. From there we can use data analysis an modeling for finding ways to optimize treatment and make sure the WWTP is running at peat efficiency.

Common causes of "toxic" shock and how microbial populations adjust

4/3/2019

While toxic shock loadings are usually found in industrial wastewater treatment plants, municipal facilities with combined industrial flows can experience loss of viable biomass from a toxic or quasi-toxic shock loading. Common causes of toxicity include:

Phenol
Cyanide
Tall oil or pine oil
d-limonene
Solvents and surfactants in high concentrations
Sulfides

No matter what the source of toxicity, the sequence of events follows a pattern:

High concentrations of the problem compounds inhibit biological activity of sensitive organisms - often this is slow growing microbes such as AOB & NOB (nitrifiers). In effect, a microbial kill.
Respiration rates slow, turbidity increases, deflocculation can occur, and indicator protozoa decline.
Organisms that are both more resistant to the compounds, utilize the compounds for energy, or fast growing (k-rate strategists) begin log phase growth. DOUR increases.
As the toxic compounds are diluted and biologically degraded, the microbial population begins to drift back to pre-shock populations.

Understanding the toxic shock pathway with respect to microbial populations helps operators mount an appropriate response. Key steps include:

Being vigilant to spills or shock loadings through routine monitoring
Determine sources and attempt to keep toxic compounds out of the system in high concentrations
If needed, use bioaugmentation to boost the k-rate strategists to move quickly from lag phase to log phase growth (shorten time for population adjustment)
If high strength waste is stored in an EQ tank, begin bleeding in slowly to avoid toxic levels (remember a poison is a factor of its concentration).
Always monitor the recovery and when you are "bleeding in" a high strength waste stream

What can you do with Microbial Community Analysis data

Common causes of "toxic" shock and how microbial populations adjust

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