20-09-2012, 01:23 PM
Advanced Method For Sewage Water Treatment
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Abstract
Sewage is waste water carrying wastes removed from residences, institutions, and commercial and industrial
establishments, together with such groundwater, surface water, and storm water as may be present. It is more than 99.9% pure water
and is characterized by its volume or rate of flow its physical condition, its chemical constituents, and the bacteriological organisms
that it contains.
Increasing volumes of domestic, hospital and industrial wastewater are being produced in cities around the world. Cities in
developing countries lack resources to treat wastewater before disposal. Even where expensive wastewater treatment plants are
installed, only a small percentage of the total wastewater volume is treated before discharge resulting in rivers, lakes and aquifers
becoming severely contaminated. So there is great need to treat waste water.
We can treat such water by various methods. The contaminants in wastewater are removed by physical, chemical, and biological
means. The individual methods usually are classified as physical unit operations, chemical unit processes, and biological unit
processes, Although these operations and processes occur in a variety of combinations in treatment systems, it has been found
advantageous to study their scientific basis separately because the principles involved do not change.
INTRODUCTION
It is essentially the water supply of the
community after it has been fouled by a variety of uses.
From the standpoint of sources of generation, waste
water may be defined as a combination of the liquid (or
water) carrying wastes removed from residences,
institutions, and commercial and industrial
establishments, together with such groundwater, surface
water, and storm water as may be present. Sewage is
water-carried wastes, in either solution or suspension
that is intended to flow away from a community. Also
known as waste water flows, sewage is the used water
supply of the community. It is more than 99.9% pure
water and is characterized by its volume or rate of flow
its physical condition, its chemical constituents, and the
bacteriological organisms that it contains. Depending on
their origin, waste water can be classed as sanitary,
commercial, industrial, agricultural or surface runoff.
LITERATURE SURVEY
Before the late 1800s, the general means of
disposing human excrement was the outdoor privy while
the major proportion of the population used to go for
open defecation. Sewage treatment systems were
introduced in cities after Louis Pasteur and other
scientists showed that sewage born bacteria were
responsible for many infectious diseases. The Early
attempts, in the 900s, at treating sewage usually
consisted of acquiring large farms and spreading the
sewage over the land, where it decayed under the action
of micro-organisms. It was soon found that the land
became 'sick'. Later attempts included the discharge of
wastewater directly into the water bodies, but it resulted
in significant deterioration of the water quality of such
bodies. These attempts relied heavily on the selfcleansing
capacities of land and water bodies and it was
soon realized that nature couldn't act as an indefinite
sink.
Sedimentation
As soon as sufficient water from tank 1 is taken in
the tank 2 i.e. up to LH2 SV1 will close. Here we are
using stirrer which is operating on motor. This stirrer is
moving very slowly at the top of the water in order to
collect all the floating solids which is not removed in
screening process. Here it slows down and the
suspended solids gradually sink to the bottom. This
mass of solids is called primary sludge. Various
methods have been devised to remove primary sludge
from the tanks. As water remains in the tank for some
time sludge get settle down at the bottom of the tank.
After some time SV4 get open and settled sludge is
taken to the drain. After a certain delay SV3 get open
and Water goes into Tank3.
Software Details:
Control engineering has evolved
over time. In the past humans were the main methods
for controlling a system. More recently electricity has
been used for control and early electrical control was
based on relays. These relays allow power to be
switched on and off without a mechanical switch. It is
common to use relays to make simple logical control
decisions. The development of low cost computer has
brought the most recent revolution, the Programmable
Logic Controller (PLC). The advent of the PLC began in
the 1970s, and has become the most common choice for
manufacturing controls. PLCs have been gaining
popularity on the factory floor and will probably remain
predominant for some time to come. Most of this is
because of the advantages they offer. In our system the
PLC program is going to control the valve i.e. is amount
of acid or base is to be add into treated water. It also
controls the positions of all the levels of the different
tanks in the process. This will help to control the system
smoothly.
CONCLUSION
In this paper, we can say that water treatment is
not easy as it seems. It has great importance in industries
as well as in society. we realize that water treatment
processes are very precise and well controlled. Using
PLC techniques we can automate the water treatment
processes. As we see water is one of the important part
of all of us and to use treated water in our daily life is
one of the great contribution in saving limited reservoir
of water.