Water, sanitation, hygiene and enteric infections in children
The Relationship of Microorganisms to Sanitation. Chapter. 13 Readers · k Downloads. Part of the Food Science Texts Series book series (FSTS). Biological wastewater treatment is the most common sanitation method in the world. This technology uses different types of bacteria and other microorganisms . Some microbes that colonize humans are commensal, whereas others have a mutualistic relationship with the host. These interactions are important for human .
Role of Microbes in Human Health
The human host and its microbial flora constitute a complex ecosystem whose equilibrium serves as a remarkable example of reciprocal adaptation.
Normally, microbe is responsible for resistance to colonization by exogenous pathogenic microorganisms. However, sometimes potential pathogenic bacteria come in close contact with the host and are responsible for opportunistic infections in immune-compromised hosts [ 3 ]. Some microbes that colonize in human are commensal that is they co-exist without harming human, whereas others have a mutualistic relationship with their human host that is both are beneficial to each other symbiotic approach.
Conversely, some non-pathogenic microbes can harm human host via the metabolites produced by them viz. Certain microbes perform specific tasks known to be useful to the human host. However, role of most resident microorganisms is not well understood. Moreover, based on evidences, now scientists are convinced that modern trends of diet, excessive use of antibiotics, obsession with cleanliness, caesarean deliveries etc.
This mini-review briefly describes about the microbes that are present in the human body under normal circumstances and do not cause any disease and are helpful to human in spending a healthy life.
Microbes on Skin Skin is the largest human organ which is the point of contact with the world. The most diverse populations of microbes present in human live on the skin. There are at least 1, different species of bacteria, fungi, viruses and other microbes which live on the skin. Most of which are harmless or even beneficial to human host. Colonization on skin is highly variable depending on endogenous host factors, topographical location and exogenous environmental factors. Symbiotic microorganisms occupy a wide range of skin niches and protect against invasion by more pathogenic or harmful organisms.
One example of bacteria that protects the skin is Bacillus subtilis. It produces bacitracin on the skin, a toxin poison that helps it in fighting with other microbes.
The property of bacitracin to act as an antibacterial agent has been exploited to use it as antibiotics.
Skin microflora may also have a role in educating the billions of T cells, priming them to respond to similarly marked pathogen [ 4 ]. Primary bacterial colonizers are Staphylococcus epidermidis and other coagulase-negative Staphylococci.
Other microorganisms that are generally regarded as skin colonizers are species of CorynebacteriumPropionibacterium and Brevibacterium. The most commonly isolated fungal species is Malassezia sp. The Demodex mites viz. Demodex folliculorum and Demodex brevis are microscopic arthropods and these are also regarded as part of the normal skin flora [ 5 ].
Microbes in Nasal Cavity A little is known about the microbes in nasal cavity. However, evidences suggested that microbiota of the nasal cavity plays a crucial role in determining the reaction patterns of the mucosal and systemic immune system. Different microbiota are found in different parts of the nasal cavity. Many studies are conducted to know about the microbiota of nasal cavity.
The studies suggested absence of Gramnegative bacteria in nasal passage that are regularly present in pharynx. However, viridans type Streptococci are sparsely present in the nasal cavity. On the other hand, species of CorynebacteriumAureobacteriumRhodococcus and Staphylococcus have been found to be present dominantly. These data suggested that microbiota present in of the nasal cavity of adult humans are strikingly different from that of the pharynx [ 6 ].
The anaerobic bacteria found were Propionibacterium acnes in The microorganisms found in the human oral cavity are called as the oral microflora, oral microbiota or oral microbiome.
This microflora comprises over species with distinct combination at different habitats. Most organisms that are colonizing are beneficial to human health but some microbes transit from a commensal relationship to pathogenicity. The reasons for the transition are not understood, however it is believed that it may be because of changes in the environment or personal hygiene [ 8 ].
Scientists have found the agonist as well as antagonist interactions between these microbes. For example, interaction between Streptococcus gordonii and Actinomyces naeslundii are both agonist and antagonist in nature.
Bacteria and microorganisms for water treatment / sanitation
Both these microbes are involved in biofilm production. Conversely, hydrogen peroxide produced by S. Another example of antagonist relationship is of Streptococcus mutanswhich is a leading cause of dental caries.
It uses quorum sensing and releases bacteriocin when introduced to other bacteria while StreptococcusActinomycesand Lactobacillus generate an acidic pH, which results in inhibition of growth of a variety of bacterial species [ 1011 ].
Microbes in Human Gut The human gut serves two major functions: It digests food, absorbs nutrients, and assists with waste excretion. At the same time, intestine serves as house for enormous population of microbes that help in digestion and guard against pathogenic microbes.
The intestinal microbiota of newborns is characterized by low diversity and a relative dominance of the phyla Proteobacteria and Actinobacteria. There are also differences between the gut microbiota of formula-fed and breast-fed infants. By the end of the first year of life, the microbial profile is distinct for each infant. Temperature affects the presence of certain species. Thus, the effect of geographic location affects species composition.
On the other hand, in industry, for example, the presence of predominantly well-defined micro-organisms can be explained by their ability to biodegrade specific components of industrial wastewater.
Bacteria are further categorized by how they get oxygen. In wastewater treatment, there are three types of bacteria used to treat wastewater entering the treatment plant: Their impacts and the treatment solutions The presence of bad bacteria or the absence of good ones can cause in particular: Low biogas efficiency of the anaerobic digester Poor flocculation and sedimentation An excess of filamentous bacteria Excess of phosphorus Low nitrogen removal efficiency NH4, NO3 The production of unpleasant odours Excess consumption of chemical products In an anaerobic digester, foam production There are generally three ways to restore an effective treatment.
First, by changing the operating settings, and waiting for the right species to colonize the environment again. Second, by completely removing the microorganisms in place when the first solution did not work. Be careful, this method is not recommended because the biomass will take several days to develop, so the water will not be properly treated during this period.
The third solution consists in injecting specially selected, cultured and multiplied bacteria in order to recover the advantage over the undesirable bacteria present in the environment. Frequent applications Microbial biotechnology offers innovative scientific applications of high ecological and economic interest. It maximizes the natural degradation processes and thus eliminates pollution at significantly lower costs than conventional physicochemical or mechanical treatment processes.
The use of bacteria differs from common process techniques in that it involves simple and natural methods, the end-result of which makes it possible to eliminate pollution without generating new pollution. Most of the time, their implementation requires the use of a dedicated bioreactor, as well as the nutrients needed to multiply them in large numbers.
The dosing is easy and requires very little operating time.
Once again, it is the temperature that has the most influence on this growth time. There are solutions to reduce this time to about a week, through seeding with selected and multiplied bacteria. There are two main advantages here: Reduce the start-up time of a wastewater treatment plant Accelerate the start-up of a mobile processing unit e.
Under these favorable conditions, bacteria develop flocs or biofilms very quickly. Finally, after a few days, the habitat is ready and wastewater can be discharged. The sizing is available on the microbiological optimization page.
Solving the presence of undesirable bacteria On activated sludge plants, the presence of filamentous bacteria is a real problem. First, the solution consists of extracting as much sludge as possible and increasing aeration.
Bactéries et micro-organismes
The good bacteria can take several days to recover the environment. If this does not work, then it is possible to destroy these bacteria with chlorine. The problem is that it kills all bacteria.
Then it will take a few weeks for normal conditions to be reached again. While the majority of operators continue to inject chlorine, we recommend the injection of dedicated bacteria. As for the accelerated start-up of a plant, the massive addition of these good populations makes it possible to quickly restore the balance in the tanks. For example, here is an illustration of the removal of floats in a clarifier.
By eliminating the fats and oils responsible for the habitat degradation Lipophilic bacteria are specialized in the decomposition of animal and vegetable fats and oils in urban WWTPs and industrial treatment plants. These bacteria are easily adaptable to all current treatment systems. On the market, there are products such as completely natural bacteria and enzymes, designed and selected for their ability to dissolve and digest fats and sludge.