Imagine trying to solve a problem when you are provided just 1% of the total data. This is essentially the case in analyzing water and wastewater microbiomes. Conventional microbiological testing methods such as culture and microscopy can identify only about 1% of microorganisms that are contained in a typical environmental sample. The remaining 99% are known to be there, but can not be identified by traditional culture tests. This 99% of unidentifiable microbes are sometimes referred to as “microbial dark matter.” Modern molecular microbiology methods such as LuminUltra’s 2nd Generation ATP® or metagenomics changes all of this, by identifying nearly 100% of microbes in common water and wastewater systems.
Let’s look at an application in wastewater treatment – Anammox. There are a handful of very unique bacteria capable of oxidizing ammonia in anaerobic conditions. These bacteria simultaneously oxidize ammonia and reduce nitrite and are known as anammox bacteria. Because these bacteria oxidize ammonia anaerobically, they are able to reduce energy needs for aeration substantially (>60%). They are also able to reduce total nitrogen using 100% less external carbon than conventional nitrification-denitrification, while also reclaiming 50% more alkalinity, resulting in lower chemical costs. Anammox bacteria are extremely slow growing and can be extremely sensitive to small environmental changes. Modern DNA methods are the only way to conclusively identify and quantify these bacteria in treatment systems to help optimize these efficient processes.
Turning to water reuse, it is no secret that Reverse Osmosis (RO) membranes can often foul with biofilms. Metagenomics techniques can be used to identify and quantify nearly every microbe in that biofilm. In one analysis, for example, it was demonstrated that biofilm bacteria carried genes for phosphonate uptake implicating a phosphonate-rich antiscalant as a cause for the biofilm formation. This diagnosis would not have been possible using conventional testing methods. A non-phosphonate antiscalant was recommended, which when implemented resolved the problem. The client was able to proceed with a multi-million dollar full-scale project, reduce chemical costs associated with biocide treatments, increase membrane life, reduce capital costs, and improve operational performance.
Some example drinking water applications of metagenomics include:
- Distribution System Nitrification: DNA data can shed light on issues with nitrification in distribution systems that consumes disinfection residual (especially chloramine).
- Distribution System Backflow: DNA data can indicate potential issues with untreated water entering distribution systems via backflow or other routes. Coliform testing will typically not detect any issues until the problem is substantial enough to consume the chlorine residual and cause potential health issues. DNA data, on the other hand, can detect bacterial contaminants such as E. coli and other fecal-associated bacteria even when a chlorine residual renders these bacteria non-viable. This information is helpful for identifying problems in a distribution system before they become major public health issues.
- Coliform investigation: DNA data can shed light on microbes in your water that are responsible for positive coliform results. Positive coliform results can cause some uncertainty and concern for regulators and utilities but many times these positive results are due to benign environmental bacteria rather than an indication of contamination. DNA data can provide this peace of mind. If there is a contamination issue, DNA data can provide a lot of information that may help understand where the contamination is originating, so it can be resolved.
Modern molecular microbial analysis methods such as metagenomics are essential to drive progress in water and manage for the future. They can help uncover new insights around the efficacy of various disinfection technologies (see this paper), and emerging concerns such as pharmaceuticals in water and “super bugs.”
The water microbiome is a grand, largely unexplored world. Thanks to the advancements of modern DNA science and technology, it’s now possible to explore this new world and create value. Over the coming months, Microbe Detectives and LuminUltra will be working to share more detailed stories and ideas about how the combination of rapid, on-site 2nd Generation ATP testing can combine with next-generation metagenomics technology to bring you a new level of efficiency you’ve not thought possible before! In the meantime, visit our DNA Test Kit page for more information.