Whenever
the topic of waste water is brought up among the industrialists, it is obvious
to think about the industrial wastes getting into the drains or into the rivers.
Some might argue that the wastewater from households is much more than
industrial output. But, in most cases of house waste, the water usually seeps
into the ground due to the lower flow rate, but in industries, the waste is
ejected into the rivers or sea directly. This results in major contamination of
the water flowing in the river. Most of the industries are therefore found in
areas with abundant water supply and suitability of removing the waste into these
waters. Unchecked proliferation of industries in such belts has been
responsible for pollution of the water since long years.
In
most of the industrialized nations of the world, the concept of waste water is
being associated with industries, because at this level, significant steps can
be undertaken to procure purer water, which can then be recycled for supply.
The idea would be to disinfect the water, so that the microorganisms are
destroyed and hence, industrial waterdisinfection is currently being researched in different stages, all across
the globe. It is a problem that concerns the entire world, since
industrialization is sought by every country for growth. So, waste water reuse
should be serious thought about and steps taken for their quick implementations.
Need to get the waste water from industries back
into use:
- Wastage – It goes without saying that water bodies in most parts of the
world are drying up due to climatic changes. Shortage of water would be seen
in the coming two or three decades, so much so that people will not be
able to get home supplies, if the water bodies keep on drying in this
particular rate. Wasting water is also rife in the society, as well as in
industries. This is apart from the fact that industries are spewing gallons
and gallons of waste water into the water bodies in and around the city.
- Drying resources – Groundwater sources are decreasing and
rivers are drying up. Ocean and sea levels are decreasing with every
passing year and therefore, in the coming years, the shortage of water
supply will be felt by the common man as well as the industries.
Lost
water from industries with plenty of organic and organism components:
Most
of the industries are dependent on water supplies in sufficient quantities for
one or the other purpose. They need it for cleaning, as raw materials or for
washing of the byproducts. As a result, much of the water flows through drains
as wastewater and is disposed into the water bodies. Lots of sludge, organic
materials, minerals, microorganisms and some toxic materials are discharged
into the water, so that the receiving water body gets polluted. In many cases,
these pollutants are of organic nature or rather full of microorganisms.
Although there are many other materials which need to be cleared from this
wasted water, if it is to be reused, removing the bacterial or organic
materials is an important consideration. Since these are able to grow in the
polluted environment of the water, a small amount of the microorganism can be
quite dangerous, especially for consumption. So, with this background, it is
necessary to consider that the industrial
waste disinfection be done for the best resources of water supply to the
communities or to the industry itself.
The
trend of installing water purification systems in many industries is a
reflection of the growing realization of reusing the wastewater. Companies are
seriously considering the proper reuse of the water and their active
participation is surely going to change the scenario of water disinfection. Such
steps are also being propagated by many environmentalists and government
authorities. It is therefore common to find that industrial water disinfection
steps are being carried out and adopted by many industries, being enforced and
ensured by government and the environmentally aware masses.
Various
methods of disinfection
Diseases
causing microorganisms are the primary concern for most of the water utilized
for public use. If there are methods adopted to disinfect the industrial water,
then a large part of the water scarcity can be handled. But, this is easier
said than done because of the proper processes to be implemented. These might
require large spaces or the infrastructure costs can be excessive. Even though
the capital required may be huge, the ability of various industries, local
water authorities and private companies to handle so much of waste water
treatment should be considered. If there is development of large scale
disinfection procedures, then plenty of water can be derived in cleaner forms
to supply the populations.
Various disinfectants found in common use in
industrial set ups:
Proactive
role from different fronts – In most of the developing countries, industrial water disinfection is being
looked at as a viable option to deliver the supply for commercial public and
industrial use. Requisites for carrying out these processes are cheaper methods
of disinfection, quick processes, adequate retrieval and assistance at
different levels. Even though the industries are ready to put up disinfection
methods, the local authorities should work with them to meet the demands of the
population. Working in public private partnership will be extremely helpful in
removing the problem of water scarcity.
- Chlorine is the commonest – One of the most economical and effective
means of water disinfection has been the use of chlorine. This chemical
compound can destroy variety of bacteria and viruses and other organisms
from the water. There are different other modalities of treatment for the
industrial water, but for disinfecting purposes, chlorine or bleaching
powder seems to be the most economical option. Chlorine gas or liquid
sodium hypochlorite can be injected into the water, so that it kills
majority of the germs. In order to make this biocide effect, continue for
certain period of time, the residual chlorine should be high. For
chlorine, the residual limit allowed is usually 0.2 to 0.5 ppm.
- Alternatives for Chlorine Required – On the other hand, chlorine is not always
safe for disinfection purposes. Industrial waste usually carries organic
materials. This is true for most of the industries, related to rubber,
pharmaceutical, petroleum and few others. Invariably, these industries
give out organic materials in their waste, which adds to the growth of
organisms. But, there are other problems of having such materials also. When
organic material is present in the industrial waste water and it is
treated with chlorine, the chemical tends to form chloramines or
trihalomethanes. These compounds are considered to be carcinogenic.
In some other cases, chlorine gets dissipated and
no residual form remains to allow for disinfection. To some extent, this
problem can be handled by adding ammonia or some form of nitrogenous compounds,
so that chloramines are formed in large amounts, which allow the residual
chlorine to stay and the trihalomethanes are not formed. Many countries are
using this procedure to derive fresh water from the industrial waste.
- Oxidizing Agents – Adding sufficient amounts of oxidizing
agents is one good way to handle the flux of microorganisms in the
industrial waste water. Oxidizing agents are used to neutralize the
membranes of the organisms and also act to kill these organisms. Potassium
permanganate is a good agent in industrial use. Higher concentration of
the compound can be used in industrial
waste disinfection, so that the resulting water has much of the
organism destroyed. This chemical can also be used in bleaching
procedures.
- Micron Filters - Micron filters are also good for preventing
the bacteria from flowing into the cleaning units. So, industrial waste
can be passed through these filters, so as to allow the bacteria of about
0.1 to 0.005 microns to remain back during the filtration process. The
downside of such filters is that they cannot be used as industrial waste
disinfectants in a large scale, due to their problem of being choked or
destroyed by the chemicals present in the waste water.
Chemical
disinfections better than mechanical industrial waste disinfection:
Having
been well established that chlorine is one of the best ways undertaken for
disinfection, it doesn’t remain as the top priority these days. After various
independent researches revealed the presence of carcinogenic and potential
toxic compounds by treating water with chlorine, chlorine dioxide has been put
forth as a good alternative.
- Chlorine dioxide disinfection advantages – Use of chlorine dioxide has been associated
with many advantages over chlorine, such benefits extending also to the
overall safety profiles and disinfectant actions. Most of the
microorganisms and spores of bacteria are removed and lysed by their
actions. Rapid chlorate and chlorite formations are responsible for the
oxidizing actions and this compound also doesn’t have serious toxicity
profile. In some countries, there are certain permissible levels of the
compound, which should be present in drinking water or reused water. So,
with stringent following of these rules, industries and local authorities
can very well ensure that the chlorine dioxide be used as a great
disinfectant in industrial water.
- Chloramine – Another chemical that has garnered
attention in recent years as an effective antioxidant is that of
chloramine. Even though the oxidizing potential is less than chlorine
dioxide, its long lasting effects go in favor of making it a popular
disinfecting agent. Chlorine can be converted into chlormaine, by adding
ammonia to the water, after chlorine has been added. Industrial water disinfection by this mechanism is gaining
popularity in many circles these days.
- Ozone disinfection – Although, ozone is not a chemical compound
like those of chlorine or related materials, it is also one of the ways of
disinfecting industrial water for reuse purposes mostly. Ozonization has
become quite popular in the present day scenario. Ozone, being an unstable
molecule, leads to the release of free radicals, which can easily
disintegrate the water organisms. These are quite effective in destroying
most of the microorganisms and even spores, so that a better disinfection
is possible. The procedure for ozonization is done in such a manner that
ozone requires to be manufactured on site, which on the other hand is a
problem for mass scale disinfection. But, it produces almost negligible
amounts of byproducts and no problems in taste or appearance. Even the
USFDA approves of ozone as a good means of purification of water and
disinfection of industrial waste water. Such procedures have been known to
many countries since the beginning of the 20th century, the
first ozone use in mass scale being done in France.
- UV Radiation – In many parts of United States, Ultraviolet
radiation has come up as an important ingredient for industrial waste
disinfection. Even in low turbid water, UV rays can be quite effective.
Like the process of ozonization, this form of water treatment doesn’t
leave behind any residual effect, besides having its effective action with
one time exposure. This is possibly sufficient enough to make the water
free from microorganisms. For highly turbid waste water, this kind of
radiation is not effective as the light rays can be scattered by the
presence of high particulate concentration. Many plants in US are being
established in large areas, where UV treatment of the waste water is done
along with an adjunctive mix of chlorine or chloramine, so that the effect
of disinfection lasts quite long.
- Solar disinfection – Another newer method, with cost effective
benefits, is that of solar water disinfection. Due to sufficient amounts
of solar light available in many countries, communities are coming up with
these plans to clean the water in their pumps or storage tanks. For small
communities also, this kind of solar power is effective. Many bacterial
species, causing harm to the body, can be destroyed by this simple method.
The
concept of industrial water purification doesn’t get restricted to only
disinfection. It can be considered only as a part of the water treatment
procedures. There are many other particulate matters, sludge and factors, which
are needed to be controlled. But, when industrial waste disinfection is being
considered, the water supposed to be reused can be treated with suitable
chemicals for effective cleaning of the microorganisms. Water disinfection has
to be done properly, in order to provide disease free water supply.
According
to their capacities to install purification and disinfectant methods in their
industries or the ability of private companies to set up their in-house plants
for purification, most industries are looking at viable options to go for industrial waste disinfection. This
water can then be used in different places and for different purposes, after
the other methods of purification have been conducted on these water
collections.
