Page 30 - March 2020 - WT Site

Aerobic Wastewater Treatment Technologies –

Contribution of Healthy Microbial Community and Impacts

Highly even community structure and rich diversity of microbes contribute to efficient treatment of the plants
By Dr. Purvi Zaveri

mmediately after commencement of first ever sewage • General measures affecting composition
treatment plant, it was evident that wastewater treatment • How do we take advantage of useful microbes?
Ifacilities would serve as a crucial barrier between
anthropogenic activities and environment. As stated in one of the Wastewater treatment plants are one of the finest examples of
UN reports, “roughly 83 million people being added to the world’s microbes (aerobes and anaerobes) being put to work for benefit
population every year” (world-population-prospects-2017), the of human race. Amongst most popular technologies, anaerobic
proportional increase in commodity demand is also expected treatment options do serve purpose of removal of toxic material,
to be observed. That in-turn will lead to generation of much but fails to meet lower HRT desired in most cases. This limitation
higher amount of effluent than being treated all over the globe. can be overcome by aerobic treatment technologies easily due to
Advancement of technologies and increase in span of product rapid growth rate of aerobic microbes. However, this condition
reach also implies that, not just industries, but effluent treatment can only be achieved if the microbial community composition is
community will have to deal with transitions and fluctuations the best suitable for the wastewater type being treated.
on daily bases. Are we really ready for that? The answer is, to
meet new permissible limits, pace of growth and environmental It is required to understand that while dealing with aerobic
protection policies it is required to come up with innovative, microbial treatment schemes, a single change form optimum
efficient, market viable solutions from research end. The solution parameter will generate direct impact on treatment efficiency.
lies in microbial community composition present in the sewage During the biological treatment, group of microorganisms
or industrial wastewater treatment plant. which act on organic waste for its oxidation and the community
developed during the processes of CETP holds the key for the
Apart from meeting these legislative requirements, plant efficient functioning of the plant (Forster et al. 2003). Let us
operation experts face a lot of issues like; excess foam formation, try to understand interplay of wastewater and microbes at large
low sludge volume index, low MLSS (in case of industrial effluent using basic microbiological understanding.
treatment plants), slurry formation, unhealthy floc formation and
foul smell at various days of the year. If we look into matter of The term “Microbial community” refers to assemblage of variety
each specific case, microbial community composition holds the of species of microorganisms living together in the same niche/
key for resolving everyday troubles too. space/ecosystem/matrices. As illustrated in figure 1, a single
organism of single type is normally referred as presence of
In this article I would like to brief readers about following points species A or B. Organism of the same species in bulk is referred as
population of species A or B. In a particular habitat, assemblage
• What are microbial community and its structure?
of multiple numbers of species in billions of numbers is thus
• How its composition affects wastewater treatment efficiency? referred as community in this article.

32 Water Today - The Magazine March 2020