Page 46 - ACCB 2020

Revista de la Asociación Colombiana de Ciencias Biológicas
issn impreso 0120-4173, issn en línea 2500-7459
dren and virtually all of the deaths are in developing Moreover, selective removal of radioactive materials
countries. Major enteric pathogens in children include like uranium can also be effi ciently achieved using this
Rotavirus, Poliovirus, Campylobacter jejuni, Escheri- technique (40). In another hand, alum is generally used
chia coli, Shigella spp., Vibrio cholerae, Aeromonas as a fl occulant to remove unwanted colour and turbi-
spp. Clostridium diffi cile and Cryptosporidium parvum. dity from water supplies. Along with those treatments,
Also, microbes like Helicobacter pylori and Burkholde- chlorination is used for water disinfection. It is gene-
ria pseudomallei, are prominent in some regions. Whe- rally carried out by adding chlorine (Cl ) or hypochlo-
2
reas, in adults, Entamoeba histolytica, Giardia lamblia, rite to water. As the chlorine is strong oxidizing agent
Hepatitis viruses, C. jejuni as well as H. pylori and chlorine treatment is highly effective against almost all
hookworm (Ancylostoma duodenale) are the emerging waterborne pathogens, with some exceptions like Cryp-
waterborne pathogens. tosporidium parvum oocysts and mycobacteria species
(41,42). Ultimately, chlorination of water helps to con-
A study carried out for the determination of bacterial trol the spread of waterborne diseases such as cholera,
contamination in rural areas of Beijing, China demons- diarrhea, typhoid, etc.
trated the bacterial contamination in drinking water.
The analysis was carried out to determine the total Considering the overall limitations of traditional me-
bacterial count, total coliforms, and E. coli and the re- thods, scientists are trying to develop novel, effi cient,
sults obtained showed the presence of 88,000 CFU/mL, and economically viable procedures for the treatment
1,600 MPN/100 mL, and 1,600 MPN/100 mL count of water which should achieve a high degree of purity
respectively, which explains the quality of water (33). in less time. Nowadays, nanotechnology is emerging
Moreover, the results of many other studies revealed the with great impact and has been used for the treatment of
severity of water contamination by various microbial water by using various nanomaterials.
pathogens and their hazards to all forms of life (34–38).
Problems in drinking water quality include the presen-
ce of organic, inorganic, and microbial contaminants in 4.Nanotechnology for water and wastewater
excess concentrations, which are the cause of various treatment
water-borne diseases. Since it is very diffi cult to pre- A wide range of applications connected with nanote-
vent these contaminants from draining into the drinking chnology in nearly all fi elds, make it a very important
water sources, the only way to maintain safer water bo- and emerging technology. Therefore, the application of
dies is to develop effi cient purifying technologies. To nanotechnology in water and wastewater treatment is
date, many technologies have been developed for puri- gaining ground in both developing and developed coun-
fying the water. Some of them are traditional methods tries. Studies carried out proved that the metal nanopar-
which are effi cient up to some extent and others are re- ticles like silver nanoparticles (AgNPs), gold nanoparti-
cent techniques which have certain advancement to the cles (AuNPs), etc. and other nano-based materials such
traditional techniques overcoming their lacunae. as nanomembranes / nanofi lters would be helpful for
the development of new water treatment technologies,
3. Traditional methods of water and wastewater which can be used to mitigate water-related problems
treatment such as waterborne pathogens, biofi lm formation, as
The prime objective of water treatment is to get safe well as the removal of toxic heavy metals, etc.(43).
and potable water. An adequate supply of pure water is
essential to human existence. The available raw water 4.1. Nanoparticles and nanocomposites as adsor-
must be treated and purifi ed before it is supplied to bents for removal of contaminants
the general public for their domestic, agricultural, in- Adsorption is employed to remove organic and inorga-
dustrial, or any other use. To purify water, a series of nic pollutants from water and wastewater. This process
treatment processes such as coagulation, sedimentation, is dependent on materials’ surface area as well as its
fi ltration, and disinfection are used. Furthermore, the- active centers that will determine the type of conta-
re are some other techniques such as activated carbon, minants in which those materials will interact. Nano-
alum, and chlorine treatments. Briefl y, activated carbon adsorbents have the advantage to provide high specifi c
acts as adsorbent useful for the removal of toxic orga- surface area, strong sorption, as well as high reactivity
nic and volatile compounds and those responsible for and short intra-particle diffusion distance. NPs can also
unpleasant taste and odour in the water, as well. (39). remove recalcitrant pollutants from water. Carbon na-

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Rev. Asoc. Col. Cienc.(Col.), 2020; 32: 42-62.