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As a part of the curriculum for the completion PG Diploma in Environmental Studies 2013-2014. We were taken for a field visit to the Bio Diversity Park at Rani Chandrima Devi Hospital, Pedda Waltair Junction, (Visakhapatnam) on 17th March2014.
FIELD VISIT TO BIODIVERSITY PARK ON 17THMARCH2014
Biodiversity and Its importance
Biodiversity is the degree of variation of life. It can be referred to the genetic variation, ecosystem variation, Species variation, Biome and particular area in the planet.
In the Etymological perspective the term Biodiversity was first introduced by wildlife scientist and conservationist Mr.Raymond F. Dasmann in a book “A Different Kind of Country” advocating the need of conservation. The term was later adopted more prominently a decade later.
Biodiversity is not evenly distributed rather it varies across the globe as well as within the regions. Among the other factors the diversity of all the living things depends on the Altitude, Precipitation, soils and temperature.
The Biodiversity hotspots are the regions of the world with high endemic species that are under threat from humans, The term hotspot was coined by Dr. Sabina Virk . The hotspots are spread all over the world the majority of the areas are in the Tropical world
Biodiversity is the result of 3.5billion years of evolution. The origin of life has not been definitely established but evidence suggests that life is definitely few hundred years after the formation of the earth.
The “Global carrying capacity” the amount of life that can live at the same time is being debated, if the limit can also cap the number of species. Most biologist are of the opinion that the human emergence is a part of new mass extinction also known as the “Holocene extinction event” caused by the impact of humans on the environment.
The field trip at Dolphin Nature conservation society (DNCS) is the only Biodiversity park situated at the premises of Rani Chandrima Devi (RCD) Hospital, Pedawaltair in Vizag was attended by the students of PG Diploma Environmental Sciences.
The (DNCS) Biodiversity park at Rani Chandrima Devi (RCD) hospital houses around 2000 species of flora which include aromatic plants, Species, Medicinal plants and water plants among which 300 trees belong to the rare species. It also houses Butterfly Park and herbal garden. The park was founded and maintained by Dr Rama Murthy and his wife Manga Thayi.
The Biodiversity park is situated in the area of 5 acres leased out from Rani Chandrima Devi Hospital. It has many plants with diversity and different ecosystems.
The trip was organized under the guidance of Prof. Uday Bhaskar Reddi of the Dept. of Environmental Sciences, Andhra University.
The first visit was to the Gymnosperms section. Below is the description of the Gymnosperms and the various plants associated with them.
Gymnosperms: The term Gymnosperms comes from the greek word Gymnospeermos that means “Naked Seeds” . The gymnosperms are a group of seed producing plants that include cycads, Conifers, Ginkgo and Gnetales.
The Gymnosperms are regarded as a “Natural Group” It is believed that the Gymnosperms originated in the late Carboniferous period. The present Gymnosperms are a result of the genome duplication millions of years ago.
The lifecycle of the gymnosperms like all the vascular plants have a sporophyte- dominant life style and the gametophyte or the Gamete-bearing phase is short lived .
The two spores the microspores and the megaspores are typically produced in the pollen cones and the ovulate cones
1) Zamia Furfuracea: It is a Cycad (seed plants characterized by stout and woody trunk with a crown of hard stiff leaves) It is a native of Mexico. Although it is not a palm tree it lives in the conditions of a Palm tree. It is also called as the cardboard plant, Cardboard Sago, Jamican Sago and the Mexican Cycad.
All the parts of the plant are poisonous to animals and the Human Beings. The toxicity causes Liver and Kidney failure and paralysis with dehydration setting in quickly. The treatment for the poisons is not currently known.
2) Agathis Robusta: It is a coniferous tree in the family of Araucariaceae, and is a native to eastern Queensland, Australia.
It is a large and evergreen tree growing straight and tall to the height of 30-50m with a smooth and scaly bark. The leaves are tough and leathery in texture with no midrib. They are arranged in the opposite pairs on the stem. The seed cones are globose. The male pollen is cylindrical
The queensland Kauri was heavily lodged in the past. Now the trees are much rarer than the european times. However they are not endangered.
3) Thuja Orientalis: It is a genus of the Coniferous trees in the Cupressaceae family. The species are two native to the North america and three native to Asia.
They are commonly called as the aboratives (Latin-Tree of life) or Thujas. Several species known as the Cedar but they are not cedars they are called the Red Cedars or the White cedars.
Thujas are evergreen trees growing from 10 to 200ft tall with stringy textured reddish-brown bark. The shoots are flat with side shoots in a single plane.
Thuja species are used as food by plants and larvae. The foilage is also eaten by deer.
They are used as ornamental trees and are used as hedges. Number of trees are grown in landscapes. The wood is light soft and aromatic, splits easily and resists decay. The oil of Thuja “Terpene Thujone” with potentially lethal properties.
In the 19th century Thuja was used for the treatement of external applied tincture or ointment for the treatement of warts, ringworm and thrush due to its medicinal properties.
Apart from the above there is an enclosure for ornamental plants also. The description of the ornamental plants are as below.
1) Ficus Krishnae (Benghalensis): Belongs to the family Moraceae. It is commonly called as the Krishna Fig. It is very large fast growing evergreen tree growing upto 30m tall with spreading branches and many aerial roots. Leaves stalked, Ovate heart shaped, 3Nerved. When young it is velvetty on both the sides .
The plant is known as Krishna Butter Cup as the mythological story goes that Lord Krishna was found of Butter and would steal it and once he was caught by his mother Yashoda, and he tried to roll the butter and hide it in the tree. Since then the leaves of this tree have retained this shape.
2) Alstonia Scholaris: It is commonly called the Indian Devil Tree. It is an evergreen tropical tree native to the Indian Subcontinent.
It is also called the It is a glabrous tree and grows upto 40m tall. It is mature bark is grayish and young branches are copiously marked with lenticels.
The flower are bloom in the month of October and are very fragrant and are similar to the flower Cestrum nocturnum.
Alstonia Scholaris or the devil tree is the genus of evergreen trees with funnels shaped flowers and milky SAP. It is used for medicinal purpose for the treatment of Malaria, Epilepsy and Asthma.
3) Bixa Orellana: It is a shrub or a small tree originating from the Americas. It is also known as the Aploppas. It is cultivated in the South East Asia after it was introduced by the Spanish in the 17th Century. It is the source of the Natural Pigment Annatto that is produced from the fruit. The plant bears pink flowers and bright red spiny fruits which bears the seed. It is also used as a colorant in dishes.
It is used to prepare body paint by the American Indians especially to the lips hence it is also called the lipstick tree. It is used by the dye in the hair by the by the men of Equador.
4) Jatropha Podagrica: It is known by several English common names like the Buddha Belly plant, Bottle plant shrub, Gout plant, Purging nut, Guatemalan Rhubarb. It is the native to the tropical Americas but it is propagated as an ornamental plant in many parts of the world.
It contains the toxic substance called Curcin making it poisonous. Care must be taken while planting the plant indoors. Everyone concerned must be informed.
5) Pterocarpus Santalinus: It is also called as the Red Sandalwood. The Species is native to India. It is found in the districts of Kadapa and Chitoor of Andhra Pradesh. And in the hilly region of Nepal, Pakistan and in Srilanka. It is valued for the nature of its timber and the furniture made from its timber. It has a great demand in China and since the days of the Quing dynasty the furniture made from it is of utmost importance and is of value.
Due to its demand in the foreign market the underground smuggling activity has increased in the recent years leading to number of arrests.
6) Bamboosa Ventricosa: It is a species of Bamboo which is a native of Guangdong province in China. The species is widely cultivated in the subtropical regions around the world for the Bulbous and the ornamental culms. The species is used for Bonsai.
Apart from the above angiosperms many other species of Angiosperms are maintained in the Biodiversity park. The preservation of the ancient species and maintaining of the continuity of the various species of Angiosperms in the middle of the concrete city is a boon to the residents.
The desert ecosystem is a biological community of interacting organisms found in a dry, barren area of land that is normally covered with sand. These are plants and animals that are adapted to the oppressive environment associated with deserts. Most of these organisms have adapted to minimise the effects of excess solar energy.
The desert ecosystem maintained at Rani Chandramani Devi hospital at Vizag is a home to many desert plants. Few of the Desert plants are listed below.
1) Selenicereus anthonyanus: It is also known as fishbone cactus. It is native to Southern Mexico. It is ornamental due to its beautiful nocturnal flowers and unusual stems.
It Is easily cultivated and is a fast growing epiphyte. Its stems are scanty and or climbing. It needs a compost of containing plenty of humus and suficient moisture in summer.
2) Agave Victoriae-reginae: It is a small species of succulent flowering perennial plant noted for its white streaks of geometrical leaves and it is a popular as an ornamental plants.
The Agave is a highly variable form, but in general the rosettes are small and compact. The victoria reginae is found in Chihuahuan Desert in the mexican states. The situatation is complicated by the by hybrids and number of Agave species.
3) Huernia Zebrina: It has a wide distribution and is found in Namibia, Botswana, Kwazulu-Natal and other provinces of South Africa. It is one of the most flowering species of the Huernias. The flower is upto 8.5cms in diameter. It is star shaped whitish or yellowish with red or purpulish spots or lines. They are very shiny and may look like plastic. The flowers are quite variable both In the color and marking.
It is not very difficult to grow Huernia Zebrina. It requires a very strong draining substrate with a portion of sharp sand. The easy way of propogation is through is by rooting stem cutting or by sowing if seeds are available half shade in summer.
The above plants are few grown in the desert ecosystem in the Biodiversity park at the Rani Chandramani Devi Hospital campus. Apart from the above many more plants are grown.
Below are the plants listed as they are grown in the campus
1) Strychnos Nux-Vomica: It is also known as Nux-Vomica, Poison Nut, Semen Strychnos and Quaker Buttons. It is a decidous tree and is native to India and South East Asia. It is a medium size tree and grows in open habits. It is a major source of highly poisonous, intensly bitter alkaloids strychine and brucine.
It is used as a medicine before the second world war. It is also used in the preparation of the homeopathic medicine Nux-Vomica(Nux-V)
2) Pistia Stratiotes: It is called as the Water Cabbage, Water Lettuce, Nile Cabbage or the Shell Flower. It is probably Pantropical. It is discover in the Nile of Africa now it is distributed along the human population along the fresh water ways.
It is a perennial monocotyledon with a thick soft leaves that form a rosette. It floates on the surface of the water its roots hanging submersed below the floating leaves.
Water lettuce is the worlds most productive freshwater aquatic plant.
3) Roystonea Regia: It is also called as the Royal Palm. It is a species of the Monoceous palms. It is native to the Carribean Islands. It is adjacent to the coast of Florida and Central and South America.
It contains a sheathing leaf base ans a petiole. They have the ability to easily release their leaves during strong wings. It is adapted to toppling during the hurricane.
It is used for decorative purpose throughout their native region and elsewhere in the tropic and the subtropics. They are considered by many as the most beautiful palms in the world. They are also decorative plants and they have minor agricultural uses.
4) Dioon Spinulosum: It is also called the Giant Dioon or the Gum Palm. It is a Cyad endemic to the limestone cliffs and the rocky hillslides in the tropical rainforests of Veracruz and Oazaca in Mexico. It is one of the tallest Cyads in the world growing upto 12m in height. The tree is also found at low elevations at 300m above the sea level.
Dioon Spinulosum prefers well drained soil and with regular water. It grows in soil containing few nutrients.
5) Cycas Circinalis: It is the only Gymnosperm found in the native Sri Lankan flora. It is widely cultivated in Hawaii for its beauty, Landscape and interiors.
The seeds are poisonous the potent of poison is removed by soaking the seed in the water. Water from the first seed soaking is harmful. But the water from the successive seed soaking is harmless. The seeds are ground and made into flour after the final soaking, to make porridge.
It is thought to be linked to the degenerative disease Lytico-Bodig in the island of Guam.
6) Cycas Revoluta: It is also called the Sago Palm, King Sago, Sago Cyad and the Japanese Sago Palm. It is a species of the Gymnosperm family and is a native to the South of Japan. It is one of the several species used for the production of Sago and is well is an ornamental plant.
It is a symmetrical plant supporting the crown of dark green leaves or the thicky trunk. It is propogated either by seed or by the removal of the Basal offsets. It is one of the most cultivated cyads. In the warm temperate and the subtropical regions.
C. Revoluta is most popular as it is seen in almost all the botanical gardens in both the temperate and the tropical regions. In many regions it is promoted commercially as a landscape plant. C. Revoluta shows the presence of alkaloids, Steroids and Tanins while the choloroform extracts shows the presence of Saponins, Tanins and Sugars. Leaflets also contain bi flavanoids.Estragole is the primary volatile compund emitted from male and female cones of C.Revoluta. It is poisonous to animals and Humans if ingested.
7) Zebrina Pendula: It is also called the wandering jew. It is the most colorful and faster growing plant. It has the purple green leaves, silver strips and purple undersides are produced along the succulent stems where root touches the soil. It creates a thick 6 to 12 inch mat of colourful foilage.
It grows in a number of soils and has to be planted in shade and receive reguar waterings. These plants have marginal soil tolerance.
Conclusion: It is evident from the fact that in the name of development preservation of nature and its eco system is being neglected. Humans have become so ignorant that they are often projecting a blind eye towards their surrounding and the ecosystem in which they live thus detroying the essential support system that is required for their very existance.
The pace at which the development activities that are taking place, ignoring the sustainability of the environment, it wont be long before we exhaust our natural resources.
5) DCNS and http://edis.ifas.ufl.edu/fp620
As a part of the curriculum for the completion PG Diploma in Environmental Studies 2013-2014. We were taken on a field visit to the Cyclone Warning Center at Visakhapatnam on 19thMarch2014
CYCLONE WARNING CENTER
FIELD VISIT TO THE CYCLONE WARNING CENTER 19TH MARCH2014
India Meteorological Department is one of the oldest organizations in our country. The meteorological observatory was established in the year 1870 at Visakhapatnam, is one of the oldest observatories on the east coast of India taking surface meteorological observations. During 1940’s the observatory was located in PWD office at Maharanipeta. Pilot balloon observatory was added afterwards. During Second World War a forecasting unit was started in the airport and an American Radiosonde station to take upper air data. It was manned by Americans. Around 1944 the station was upgraded to a class 5 observatory with self recording instruments and was headed by Dr.P. Koteswaram as Meteorologist Grade-I. Few years later the observatory was shifted from Maharanipeta to Airfield in October 1948 upgraded to class I on 1.4.1950. During that period it was Dependent Meteorological Office (DMO) and it was reduced to Secondary Meteorological Office (SMO) from 1.6.1951. It was again upgraded to DMOin1965.
Pilot Balloon observatory was shifted from Airport to Andhra university campus during 1949-1950 and Fan type Radiosonde system, Radiation unit and Metax Radio Theodolite units were also started during the same period in university campus. Seismological unit was established in 1961 in Andhra university campus. Metax Theodolite was replaced by a Salenia Radar to take upper air observations.
The present Radiosonde building of CWC in Kirlampudi layout, opposite to Andhra university was constructed during 1970. The Radiosonde unit was shifted to this newly constructed building in 1971. Simultaneously, an S-Band (10 cms) JRC make Cyclone Detecting Radar JRC, first of its kind in India was installed in May 1970 on Dolphin’s Nose hill close to light house. Meteorologist Grade-I (Dr. Sen Roy) was in charge of this office including Meteorological office at Airport, RS/RW unit, Pilot Balloon observatory, Radiation and Seismological units (at Andhra University).
Cyclone Warning Centre (CWC) started its functioning from RS/RW building from 23.09.1974 with Meteorologist Grade-I as in charge. Forecasting unit was closed at airport, however current weather and surface observatory were continued. Port Meteorological Office (PMO) was commissioned in March 1972 in Fringe house near Visakhapatnam Port. Radiation unit, which was established in 1960, shifted to RS/RW building in 1980. APT unit to receive cloud imageries from satellite was started functioning from June 1977 in Andhra university campus.
The Japanese JRC radar on Dolphin’s Nose was replaced by EEC radar in May 1982. Surface observatory was shifted to CWC building in 1982.
Micro earth station, also known as V-SAT was installed on 13.08.1983. The observatory at Air port was handed over to Navy in 1986. APT unit was upgraded to Secondary data Utilization Centre (SDUC) in 1984. Disaster Warning System now known as Cyclone Warning Dissemination system was installed in 1985. PMO and SDUC units were shifted to RS/RW building in 1991. Semi-automatic computation system of RS/RW data was introduced in January 1991. Selenia Radar of RS/RW unit, which was installed in March 1968, was replaced by EEC Radar in November 1997 with a computerized work station for operation. SDUC computer was installed on 16.02.1993 to receive the pictures from Geostationary satellite. High Wind speed recorder was installed in September 2002. World space digital data receiver to receive meteorological data pictures, charts and prognostic charts from New Delhi through satellites was installed in July 2003. Gematronik (Germany) make S-Band Doppler Weather Radar (DWR) was installed on Kailasagiri hill in July 2006 as replacement for Cyclone Detection Radar of Dolphin’s nose. Automatic radiation instruments and new high wind speed recorder were installed in 2009. New GPS system replacing Mark-IV Radio sonde and EEC Radar for taking upper air observations, was installed in May 2009.
Indian Meteorological department in Visakhapatnam takes care of the following reading as described below
Irradiance is the amount of radiant energy incident on the surface per unit area per unit time. It is measured in Wm-2 (Watt per square meter)
1) Global Solar Irradiance: Irradiance is the power of electromagnetic radiation per unit area (radiative flux) incidence on the surface. Solar irradiance on the horizontal surface due to both diffuse sun rays and diffuse sky radiation. The instrument used to measure Global irradiance is Thermoelectric Pyranometer.
a) It measures the Solar Irradiance from 300-4000nm
b) Sensor: Blackened copper constantan thermopile covered with two concentric glass domes which are transparent to radiation from 300-4000nm
c) The Generated emf by thermopile is proportional to incident radiation. The typical value is approximately 5micro volts/watt/sq.metre
d) It is used for instantaneous measurement and continuous recording of Global, Diffused, Reflected Solar irradiance
2) Diffuse Solar Irradiance: It is the solar radiation on the horizontal surface due to sky radiation only. The instrument used to measure Diffuse Solar Irradiance Thermoelectric Pyranometer with shading ring.
The Diffuse sky irradiance is measured with a Pyranometer and the shading ring that must be corrected and compensated to the sky radiation cut of by the ring. This correction is generally computed on the basis of the geometric area of the sky cut off and assuming the isotropic sky. The Diffuse irradiance components is divided into three components
a) Rayleigh scattering component
b) The aerosol scattering component
c) The components accounting for multiple reflection
3) Direct Solar Irradiance: It is the solar irradiance on a surface held perpendicular to the sun rays and diffuse sky radiation that is obstructed. The instruments used to measure Direct Solar Irradiance is Angstrom and Thermoelectric pyrheliometers
4) Terrestrial Radiation: It is a long wave radiation that is emitted by the earth back into the atmosphere. Most of it is absorbed by the water vapor in the atmosphere, while less than ten percent is radiated directly into space. The amount of radioactive elements in the soil varies widely and is the source of continuous exposure of Human beings to terrestrial radioactivity that depends on the type of soil and its uses.
5) Sunshine recorder: The sunshine recorder is used to measure the duration of the sunshine. It is instrumental in capturing the radiation of different measures.
6) Barometer: The pressure of the atmosphere at any point of time is the weight of the air column which stands vertically above the unit area with the point at its center. The atmospheric pressure is measures by the means of mercury barometer where the height of the height of the mercury column represents the atmospheric pressure.
7) High wind speed recorder (HWSR): A newly designed HWSR system has been installed at Visakhapatnam and same is already installed at other coastal stations along Bay of Bengal. These are Digha, Puri, Chennai, Nellore, Machilipatnam & Karaikal and on the West coast Mumbai (Colaba).
HWSR has solid state sensors with no moving parts. It is capable of providing uninterrupted data in the cyclone prone coastal areas in severe weather conditions including and winds of high speeds and heavy rains. The system is capable of measuring wind speeds of upto 0-65mps with and accuracy of 1.5 per cent rms and a resolution of 0.01mps.
HWSR consists of a display unit with an easy read out of wind information. The data logger with a 22bit A/D converter, a strip chart recorder with a selectable recording speed and a PC for downloading the data from the data logger. The system is also provided with 48hr back-up power supply (UPS). It has lightening protection for the sensor.
Two axis (X,Y) wind sensor uses the ultrasonic technology with no moving parts. The system does not need any expensive calibration tools. IMD carried out calibration of ultrasonic wind recording sensors in its wind tunnel.
The true wind speed is calculated using a projection manometer reading using the formula 3.8245, mps where diff is the manometer readings (original-actual after attaining the desired speed)
Working Principle: The two axis ultrasonic sensor works on the principle of travel time taken by the 40KHz ultrasonic sound pulse between the trans-receivers located in E-W and N-S direction seperated by a distance of 115mm. The travel time is detected and measured by the circuit in the sensor. From the travel time TE-W(sound pulse travel time between east transreceiver to the west transreceiver) and TW-E( sound pulse travel time between west transreceiver to the east transreceiver) are sampled from E-W. Similar measurements of the travel time done by the N-S transreceiver and TN-S, TS-N and measured. The processor in the sensor takes 40 samples of these travel times per second.
There are two modes of operation for the system:
a) Measurement mode- which is the normal mode of operation (by default) from power up onwards.
b) Interactive mode- allows the anemometer to be set up and interrogated.
The ultrsonic sensor was set to point north, using north allignment indicator on the base of the instrument. Separate earthing was provided for the sensor in order to protect it from the lightning. A typical photograph where sensor is installed with lightning protection.
The incoming wind speed is displayed in 3digits, seven segment LED display of 14.3mm height . The gust display is three digit 7-segment display 10.1mm height. The direction is indicated by 36LEDs circularly placed having amber color. The scale selection option in knots ,mph and kmph,is available on a press of the button.
The Data Logger consists od four analogue input channels, with 22-bit analogue to digital converter. It has 1MB cyclic memory and averaging interval programmable from 1minute onwards.
The D/A converter in the unit converts incoming wind speed data to analogue voltage in the range from 0-1V for 0-65mps. The converter also converts the wind direction signal for 0-4000 to the analogue voltage in the range of 0-1V and feeds to the memory module of data logger.
It has the provision for telephone modem housed inside the logger casing for down loading the data remotely. It has RS232 conectivity for computer and also for satellite transmitter.
The strip chart recorder works on the principal of comparing the input voltage against the delivered variable voltage. In a comparator, the output of the comparator drives the DC mortor till the vsariable voltage is equal to the input voltage. The recording pen is connected to the motor by mechanical means. The magnificient/Scaling can be adjusted by magnificient of the varable voltage source.
The variations in the wind directions and the wind speed are presented in the following graphs below.
The above graph represents 1-minute average wind speeds (in mps) as recorded by the system, when cyclone was 80km south of machillipatnam.
In the above graph 1-hour average wind speed (in mps) as recorded by the system from 1600h. of 15dec to 1700h 16Dec.
The graph-3 represents the peak wind speeds that were observed between 1800h and 1900h. Hence 10-minute average wind speeds (in mps) as recorded by the system between 1830h and 1930h.
In the above graph 1-minute average wind speeds (in mps) as recorded by the system between 1830h to1930h
The above graph represents the 1-minute average wind speeds (in mps) as recorded by the systems after the cyclone crossing the coast .
The above graph represents the changes in the direction (in degree) of the wind after it crosses the coast.
The variation of the wind speed and the wind direction is observed when the cyclone is crossing the coast. However no changes were observed when the cyclone was stationed 80km south of the station.
8) Barograph: A Barograph is a recording aneroid barometer. It is used to monitor pressure. The pointer is an aneroid barometer is replaced with pen. It produces a paper or foil chart called a barogram that records a barometric pressure.
A Barographs use one or more aneroid cells acting through the gear or level train to drive a recording arm that has its extreme end either a scribe or pen. A scribe records a smoked foil while a pen records on a paper using ink, held in the knib. The recording material is mounted on a cylindrical drum which is rotated slowly by clockwork. Commonly the drum makes one revolution per day, per week, per month and the rotation can be selected by the user.
9) Cup anemometer: A cup anemometer is a scientific instrument used to measure the wind speed. This device is named for the cups used to capture and measure wind. They are able to measure the wind speeds more actually. Most versions cannot measure wind direction.
Wind spins the cups in the anemometer and stronger winds spin the cups more rapidly. The specific ratio between the speed and the speed of the speed of cup rotation varies based on the particular specifications of a given instrument. A standard cup anemometer is unable to specify the direction of the wind, and is usually paired with the second instrument which is as simple as a weather wane. Other versions of cup anemometer uses cups of different sizes and shapes and can use the different drag on different cups to determine the direction of the wind blowing.
10)Sky radiometer (Radioactive Collectors): It is a device used to measure the strength of direct solar radiation and diffuse sky radiation through wavelength. It automatically confirms the position and elongation of the sun using personal computer and records the observed data. As it is equipped to sense rain drops the measurement automatically stops when it rains. This instrument helps to measure the direct solar radiation, diffuse sky radiation and accordingly estimate particle size, density and aspects of diffusion and absorption. It is also used to observe yellow and sand phenomenon in the spring season.
11)Sun Shine Card: It is a strip of paper that is calibrated in hours and that is burnt by the Sun’s Rays. It registers the duration of the sun rays. It is inserted in the sunshine recorder to capture the sun rays.
Conclusion: The meteorological department at Visakhapatnam is doing an incredible work in weather forecasting the and early cyclone warning system. This helps the fishermen in planning their course of activities which prevents them from being entangles in a cyclone in the middle of the sea.
As a part of the curriculum for the completion PG Diploma in Environmental Studies 2013-2014. We were taken for a field visit to Visakhapatnam Steel Plant on 21st March2014
VISAKHAPATNAM STEEL PLANT
FIELD VISIT TO VIZAG STEEL PLANT ON 21ST MARCH2014
As a part of the field visit for the students of the PG Diploma environmental Studies 2013-2014 we were taken to Visakhapatnam Steel Plant on 21stMarch2014. We were taken to the Coke processing plant which details are as below.
COKE OVEN BATTERIES
There are 4 batteries with each battery having 67 Ovens. The volumetric capacity of each oven is 41.6m3. The dry coal charge per oven is 32t.
At the time of commissioning VSP is proud of having the largest and technically unique coke oven batteries in the country with a height of 7 meters. It has the provision of selectively crushing of the coal to improve the coke quality. The dry quenching of coke to 100% is obtained using Nitrogen gas. The power is generated from the waste heat that is recovered from BPTS (Back Pressure turbine Station)
The production capacity for 3batteries is 2.635MT of gross coke per annum and 2.261MT of BF coke per annum.
Coal is converted into coke by heating the prepared coal blend charge in the coke ovens in the absence of air at a temperature of 1000oC-1050oC for a period of 16/19 hours. The volatile matter of coal liberated during carbonization is collected in gas collecting mains in the form of raw coke oven gas passing through stand pipes and direct contact cooling with ammonia liquor spray. The gas cooled from 800oC to 80oC is drawn to Coal Chemical Plant by Exhauster. The residual coke is pushed out of the oven by pusher car through a guide into coke bucket. The red-hot coke is taken to coke dry cooling plant for cooling.
The main by product in the process of coke making is crude coke oven gas and this has lot of valuable chemicals. Coal Chemical Plant recovers Ammonia (NH3), Tar and Benzol from CO-Gas. The primary By-products from Crude CO Gas are Ammonium Sulphate (NH4)2SO4, Crude Tar, Crude Benzol and cleaned coke oven gas. The cooled coke from CDCP (Coke Dry Cooling Plant) is separated into 3 fractions, BF Coke i.e. +25-70 mm which is sent to Blast Furnaces, Coke Breeze i.e. +0-15 mm which is sent to Sinter making and nut coke i.e., +15-25 mm, which is also used in the Blast Furnaces.
Sintering is an agglomeration process of fine mineral particles into a porous mass by incipient fusion caused by heat produced by combustion within the mass itself. Iron ore fines, coke breeze, limestone and dolomite along with recycled metallurgical wastes are converted into agglomerated mass at the Sinter Plant, which forms 70-80% of iron bearing charge in the Blast Furnace. The vertical speed of sintering depends on the suction that is created under the grate. At VSP, two exhausters are provided for each machine to create a suction of 1500 mm water column under the grate.
Visakhapatnam steel plant has Two Sintering Machines of Dwight Lloyd type each having 312M2 of total grate in each area and One sintering machine of Dwight Lloyd type having 408M2 of total grate area.
Commissioning of the Sinter Plants:
Base Mix Preparation-03.11.89
Machine-1 Commissioned: 14.11.89
Machine-2 Commissioned: 27.12.91
Machine-3 Integrated trial run for commissioning on 4thJuly13
The salient features of the Sintering plant are:
- on the ground melting of sintering base mix
M/C-1&2 has the
- Bed Height of 500mm
- Straight Line Sinter Cooler
M/C-3 has the
- Bed height of 700mm
- Chamber type Ignition furnace with roof mounted energy efficient burners
- 27m long extended hood with hot air supply with 4 feed points
- Circular Sinter Cooler with waste heat recovery system
- Calcined lime addition at mixing and Nodulizing section of Sinter machine building
The production capacity of the Sinter Machine 1&2 is 5.256MT of Gross Sinter per annum and the production capacity of Sinter Machine 3 is 3.611MT of gross sinter per annum
BLAST FURNACE IN THE VISAKHAPATNAM STEEL PLANT
Iron is made in the Blast Furnaces by smelting iron bearing materials with the help of coke and air. The solid charge materials like sinter, sized iron ore, coke etc. are charged in the vertical shaft of the Blast Furnace at top and hot air blast is blown through the tuyeres located at the bottom. The oxygen from the hot air combines with the carbon of the coke and generates heat and carbon monoxide. The gases, while ascending upwards react with the descending charge materials. Eventually the charge melts and hot metal and slag are produced and tapped out. The cooled gas is also used as fuel in the plant. The Paul-Wurth, bell less top system is installed for furnace charging.
Visakhapatnam Steel Plant has two blast furnace of 3200cum. Useful volume each and one blast furnace of 3800cum of useful volume.
Salient features of Blast furnace 1&2
- Conveyorised charging of blast furnace
- Paul-Wurth “Bell-Less” top charging system for Blast furnace
- On-line correction of coke moisture and batch weights
- Circular cast house with four tap holes and no slag notch
- Cast house slag granulation plant
- Tuyere leakage detection system
- Gas expansion turbines for power generation by utilizing the blast furnace
- Automation by Programmable Logic Controllers (PLC)
Salient features of Blast furnace 3
- New generation Parallel Hopper Bell Less Top
- BF Cooling elements (Cast Iron Staves & Copper Staves)
- Flat Cast house Equipment (by TMT)
- INBA slag Granulation system
- Annular Gap Scrubber
- Pulverized Coal Injection System
- Hot Stoves (Internal Combustion Chamber)
The production capacity of the Blast Furnace is:
- 3.4MT of Hot Metal per annum for Blast Furnace 1&2
- 2.5MT of Hot Metal per annum for Blast Furnace 3
STEEL MELT SHOP (SMS) AND CONTINOUS CASTING
Steel is made in steel melting shop in the refractory lined vessels called LD Converters by blowing oxygen through the hot metal bath. While iron making is a reduction process, steel making is an oxidation process. The oxygen reacts with the carbon in the hot metal and this reaction releases large quantities of gas rich in carbon monoxide along with huge amount of dust. The gases released from the converter are collected, cooled, cleaned and recovered for use as fuel in the steel plant. The entire molten steel at VSP is continuously cast at the radial type continuous casting machines resulting in significant energy conservation and better quality steel. 100% Continuous casting on such a large scale has been conceived for the first time in India.
The commissioning of Steel Melt Shop (SMS)
- Converter-A-1st Heat-06.09.90
- Converter-B-1st Heat-04.03.91
- Converter-C-1st Heat- 25.07.92
- Converter-E-1st Heat- 30.10.13
Visakhapatnam Steel plant has two facilities of the steel melt shop. The details of the facilities are as below:
1) Steel Melt Shop facility-1
- Three LD converters of 133 cum. Volume each
- 6nos. of 4 – strand continuous bloom casting machines
2) Steel Melt shop Facility-2
- Two LD converters of 150cum volume each
- 1no. of 6-Strand Continuous Billet-Cum-Round Caster
- Two LD converters of 150cum. Volume each
- 2 nos. of 6-Strand Continuous Billet Casters
- Hot Metal Desulphurization Plant (HMDP)
- DOG House
The salient features are:
- 100% continuous casting of steel
- Converters gas cooling, cleaning and recovery system
- Computerization of the converter process
Production capacity of the steel Melt Shop (SMS):
- SMS-1:3.0MT of liquid steel per annum & 2.820 MT of CC Blooms per annum
- SMS-2:2.8MT of liquid steel per annum & 2.730 MT of CC Blooms/Rounds per annum
EFFLUENT WATER TREATEMENT
The production of iron from its ores involves powerful reduction reactions in blast furnaces. Cooling waters are inevitably contaminated with products especially ammonia and cyanide. Production of coke from coal in coking plants also requires water cooling and the use of water in by-products separation. Contamination of waste streams includes gasification products such as benzene, naphthalene, anthracene, cyanide, ammonia, phenols, cresols together with a range of more complex organic compounds known collectively as polycyclic aromatic hydrocarbons (PAH). The conversion of iron or steel into sheet, wire or rods requires hot and cold mechanical transformation stages frequently employing water as a lubricant and coolant. Contaminants include hydraulic oils, tallow and particulate solids. Final treatment of iron and steel products before onward sale into manufacturing includes pickling in strong mineral acid to remove rust and prepare the surface for tin or chromium plating or for other surface treatments such as galvanization or painting. The two acids commonly used are hydrochloric acid and sulfuric acid. Wastewaters include acidic rinse waters together with waste acid. Although many plants operate acid recovery plants, (particularly those using Hydrochloric acid), where the mineral acid is boiled away from the iron salts, there remains a large volume of highly acid ferrous sulfate or ferrous chloride to be disposed of. Many steel industry wastewaters are contaminated by hydraulic oil also known as soluble oil.
In order to treat the effluent water before releasing the same Visakhapatnam steel plant is credited of having a self sustained effluent water treatment plant. Since the industrial wastewater treatment covers the mechanisms and processes used to treat waters that have been contaminated in some way by anthropogenic industrial or commercial activities prior to its release into the environment or its re-use. Most industries produce some wet waste although recent trends in the developed world have been to minimize such production or recycle such waste within the production process. However, many industries remain dependent on processes that produce wastewaters.
So, industries produce wastewater, otherwise known as effluent, as a bi-product of their production. The effluent contains several pollutants, which can be removed with the help of an effluent treatment plant (ETP). The “clean” water can then be safely discharged into the environment.
ENVIRONMENT MANAGEMENT DEPARTMENT (EnMD)
The environmental requirements relating to Visakhapatnam steel Plant is met by the department. The parameters relating to ambient air, stacks, effluents, work zone environment, sound, waste management, sub-soil water, marine water and fugitive emissions ( from the coke oven batteries) are regularly monitored by the Environment Management Department (EnMD) as stipulated under consent conditions and the statutory orders from APPCB/CPCB/ MoEF. All these monitoring activities are carried out as per the frequency prescribed by the APPCB/CPCB/MoEF and is in compliance with all the norms ensured.
Conclusion: Visakhapatnam steel plant is doing an incredible job in meeting the requirements of the environment as well as meeting the needs of the organization in the business perspective. It is of a matter of interest to see the Balance the organization has maintained in meeting the needs of the corporate as well as complying to the environmental requirement.
I would be a matter of aspiration to the common man if majority of the organizations follow the model of balancing the environmental requirement as well as meeting their corporate needs.
As a part of the curriculum for the completion PG Diploma in Environmental Studies 2013-2014. We were taken for a field visit to Sewage Treatement Plant (Vizag) on 25th March2014
SEWAGE TREATEMENT PLANT (VISAKHAPATNAM)
FIELD VISIT TO SEWAGE TREATEMENT PLANT ON 25ST MARCH2014
Introduction: Water treatment is the process in which water is made suitable for its applications or returning to its natural state. The required treatment depends on its application. Water treatment involves Science, Engineering, Business and Art. The treatment includes mechanical, Biological and Chemical methods.
General Method of treatment of water:
As a part of the field trip project for the students of the PG Diploma in environmental studies we were taken to the secondary sewage treatment plant in the old city area of Visakhapatnam.
Process flow diagram of Sewage Treatment Plant
List of units in Water Treatment Plant:
This project is being implemented on PPP basis. Public–private partnership (PPP) describes a government service or private business venture which is funded and operated through a partnership of government and one or more private sector companies.
Presently, with the demand for water pegged at approximately 370 MLD against the water supply of 229 MLD, the city of Vishakhapatnam is facing shortage of water. As a preliminary step to partly bridge the demand-supply gap of water in the city, GVMC has taken the initiative to substitute a part of the incremental industrial water demand with treated water. The water thus conserved by GVMC would be supplied to the households in Vishakhapatnam.
Project Implementation / Scope of Work:
Accordingly the proposed project is taken up for implementation through the Design-Build-Finance- Operate-Transfer (DBFOT) route. The project would be implemented over a Concession period of 26 years including a construction period of 12 months and envisages the design, finance, construction, operation and maintenance of a TTP at the site provided by GVMC. GVMC will supply 60 MLD of secondary treated sewage from its two STPs at Appughar and Old Sewerage Farm near Laxmi Talkies for treatment at the proposed TTP. A combination of the Ultra Filtration (UF) and the Reverse Osmosis (RO) processes has been proposed for the implementation of the proposed TTP.
As a part of the project, the VWRIPL (Visakha Water Reclamation Infra Private Limited) will take-over the operations and maintenance of the 2 STPs at Appughar and Old Sewerage Farm near Laxmi Talkies. The VWRIPL (Visakha Water Reclamation Infra Private Limited) will bring the secondary treated sewage from the 2 STPs to the site of the proposed TTP. The VWRIPL (Visakha Water Reclamation Infra Private Limited) will also set up the necessary distribution infrastructure for the distribution of tertiary treated water to the industrial users identified.
The total cost of the project is estimated to be approximately Rs. 170.50 crore including the capital cost of Rs. 154.12 crore incurred on the project components described above and the soft cost of Rs. 16.38 crore incurred on contingencies, margin money for working capital and the Interest during Construction (IDC). This project cost will be incurred over a gestation period of 12 months.
PROPOSED TREATMENT SCHEME:
The following are the main components in project execution.
- Conveyance of secondary treated sewage from Appughar to TTP at Lakshmi Talkies STP.
- Setting up of Tertiary Treatment Plant.
- Conveyance of Tertiary treated water from Lakshmi Talkies STP to Industries.
i) Conveyance of Secondary Treated Sewage from Appughar STP to TTP
The TTP plant has to be provided for the combined capacity of the STP’s at Appughar and Lakshmi Talkies. The secondary treated sewage from existing sewage treatment plant at Appughar shall be conveyed to the proposed tertiary treatment plant location.
Distance from Appughar to Lakshmi Talkies STP: 10.0 Kms
Designed Pumping Capacity: 25 MLD
ii) Tertiary Treatment Plant:
The influent characteristics to TTP from combined secondary treated sewage from STP’s @ Appughar and old sewerage farm are as follows:
|Designed Capacity of TTP||m3/day||63000|
|pH||–||6.5 – 8.5|
|Total Suspended Solids at 1050C||mg/Lit||50|
|Total Dissolved Solids||mg/Lit||2000|
|Biochemical Oxygen Demand||mg/Lit||30|
Stages in Treatment of Sewage Water:
Filtration is employed in waste treatment wherever suspended solids must be removed in practice. Filtration is most often used to polish waste water following the treatment. In primary waste treatment filters are often used to remove oil and suspended solids before the biological treatment prior to final discharge and reuse. In the first stage treated sewage shall be polished by Gravity. Dual Media Filter consists of graded media of pebbles, sand & anthracite.
Gravity Separation:Most waste treatment systems employ a gravity separation step for suspended particle or oil removal.
The settling rate of a particle is defined in terms of “free” versus “hindered” settling. A free settling particle’s motion is not affected by that of other particles, the vessel’s walls, or turbulent currents. A particle has a hindered settling rate if there is any interference from these effects.
The free settling of a discrete particle in a rising fluid can be described as the resolution of several forces-gravity, the drag exerted on the particle, and the buoyant force as described by Archimedes’ principle. The particle’s velocity increases until it reaches a terminal velocity as determined by these forces. The terminal velocity is then:
v = velocity, ft/sec
g = gravitation constant, ft/sec2
mP = mass of the particle, lb
rP = density of the particle, lb/ft3
rf = density of the fluid, lb/ft3
Aa = cross sectional area of the particle ex-posed to the direction of motion, ft2
Cd = drag coefficient, a function of particle geometry
Gravity settling is employed primarily for removal of inorganic suspended solids, such as grit and sand. Therefore, in the approximation of the drag coefficient, it is assumed that particles are spherical. Further, if a Reynolds number of less than 2.0 is assumed, the settling velocity of a discrete particle can be described by Stokes’ settling equation:
|V =||GdP2(rP – rf)|
DP = particle diameter, ft
µ = fluid viscosity, lb/ft-sec
The terminal velocity of a particle in the “free” settling zone is a function of its diameter, the density difference between the particle and the fluid, and the fluid viscosity.
The equipment employed for gravity separation for waste treatment is normally either a rectangular basin with moving bottom scrapers for solids removal or a circular tank with a rotating bottom scraper. Rectangular tanks are normally sized to decrease horizontal fluid velocity to approximately 1 ft/min. Their lengths are three to five times their width, and their depths are 3-8 ft.
When wastewater contains Hydrocarbons the removal of these hydrocarbons becomes a problem. Since oil is lower in density than water it is not emulsified. It is separated in a dual purpose vessel that allows the sedimentation of solids. The basic principles governing th e separation of oil from water by gravity differential is expressed in strokes law.
In Gravity the air flotation units are designed in the surface loading rate that is a function of waste flow and rise in velocity of the contaminates floated by air bubbles. The retention time is dependent on the depth of the tank.
In gravity the diameter of the particle plays an important role in separation. Polyelectrolytes are used to increase the effective particle diameter. Polymers are also used to destabilize oil and water emulsions allowing free oil to be separated from water.
Filters used for waste treatment may be designed with Single-Dual or Multimedia and maybe of pressure or gravity type.
The Sludge from liquid solid separation contains from 1% to 5% total suspended solids. Because of the cost savings associated with the smaller volumes of sludge, there is an economic incentive to remove additional amounts of water. Dewatering equipment is used to remove the additional amount of water in much shorter time span than nature would by Gravity.
The Gravity drainage zone is flat or slightly inclined belt which is unique to each press model. In this section the sludge is removed by the gravity drainage of the free water. The gravity drainage zone must increase the solids concentration of the sludge by 5%-10%. If the sludge does not drain well from this zone the sludge can be squeezed from the belts or the belt mesh can be blinded. The effectiveness of the gravity drainage zone is the function of the sludge type, quality and conditioning along with the screen mesh and the drainage of the drainage zone.
The centrifugal force of 3500-6000 times the force of gravity is used, is used to increase the sedimentation rate of solid sludge particles.
Water is drained from the sludge cake by gravity through the sand and gravel bed. This process is complete within the first 2 days. All the additional drying that is required is done through evaporation which takes up to 2-6 weeks. For this the climatic conditions like the frequency, rate of precipitation, wind velocity, temperature and the relative humidity plays an important role in the operation of the sludge drying beds.
Microfiltration Systems: It is a type of membrane separation technology used in waste water treatment plants which is developed to remove foreign particles that cause turbidity in water. It is suggested as an alternative method for achieving better water clarity and is considered better than the conventional filtration processes.
The principle on the working of the whole system is depended on the use of a vacuum pump to draw water across the filter and thus particle larger than the porous membrane gets trapped. Since the pore size is small enough to capture microorganisms, conventional waste water treatment plant that is equipped with microfiltration technology will usually void the need to have additional chemical process to kill harmful pathogens
Microfiltration usually is used as a pre treatment for other separation process such as ultra filtration, and the post treatment for granular media filtration. The typical particle size for microfiltration ranges from 0.1 to 10µm. In terms of approximate molecular weight these membranes can separate macromolecules generally less than 100000g/mol.
The membrane filtration processes are distinguished by three major characteristics, Driving force, retentate stream and permeate stream. The microfiltration process is a pressure driven with suspended particles and water as retentate and dissolved solutes plus water as permeate. The use of hydraulic pressure accelerates the separation processes by increasing the flow rate of the liquid stream but does not affect the chemical composition of the species in the retentate the product streams.
The treated water from micro filtration shall be further treated in Reverse Osmosis (RO) Units. The treated water from RO Units shall be recycled to industries. RO is the final category of membrane filtration, and removes particles larger than 0.1nm. The RO process of water purification does not require any thermal energy. Flow through RO systems can be regulated by high pressure pumps. The recovery of purified water depends upon various factors, including membrane sizes, membrane pore size, temperature, operating pressure and membrane surface area Designed Treated Water Characteristics from TTP:
|1||Designed Capacity of TTP||m3/day||57000|
|pH||–||7.0 – 7.5|
|Total Dissolved Solids||mg/Lit||100 – 250|
|Chemical Oxygen Demand||mg/Lit||BDL|
|Biological Oxygen Demand||mg/Lit||BDL|
|Oil & Grease||mg/Lit||BDL|
Tertiary Treatment Process Stages: The purpose of tertiary treatment is to provide a final treatment stage to raise the effluent quality before it is released into the environment (Sea, River, Lake, Ground etc). More than one tertiary treatment process may be used at any treatment plant. It is also called “effluent polishing”.
“Tertiary Filtration” systems must include a physical filtration process designed to achieve a effluent quality of 10parts per million per suspended solids.
The recycling plant is designed 63 MLD Capacity.
1) Gravity Dual Media Filter: The advantages of dual media filtration are higher rates and longer runs. Anthracite, Sand and Garnet beds have operated at normal rates of approximately 5gpm/ft2. And peak rates as high as high as 8gpm/ft2 without loss of effluent quality.
2) Micro Filtration: Micro Filtration is one of the membrane filtration processes. Raw water is filtered by passing through a plastic or polymeric material which contains millions of small pores. Filtering occurs because the membrane pores are large enough for the water to pass through it. Yet small enough to restrict the passage of undesirable material such as particulate matter and pathogenic organisms.
Membrane configuration can vary between manufacturers. The most common type of membrane is the “hollow fiber”. Membranes are cast into small hollow tubes or straws, nominally one meter in length. Thousands are bundled together and the ends are bonded into an epoxy bulkhead or “potting”. The ends of potting are cut off to allow access to inside of the fibers from the end of “potting”.
Typically water is pumped from the outside of the fibers, and the clean water is collected from the inside of the fibers. This is called “outside to inside”. This flow direction is sometimes reversed depending on the manufacturer or membrane configuration.
3) Clean-in-Place (CIP): It is a method of cleaning the interior surface of pipes, Vessels, process equipment, filters and associated fittings without disassembly. Upto the 1950 closed systems were disassembled and cleaned manually. With the advent of CIP industries that needed to be cleaned frequently like the industries that needed to maintain hygiene and include dairy, beverage, brewing, processed foods, pharmaceutical and cosmetics.
Industries are benefitted due to the fact that in CIP the cleaning is much faster, less labor intensive and more repeatable and poses less risk of chemical exposure to its people. CIP started as a manual practice involving balance tank, centrifugal pump and connection to the system to be cleaned. Since the 1950’s CIP has been involves into a more automated systems using programmable logic controllers, multiple balance tanks, sensors, valves, heat exchangers, data acquisition and specially designed spray nozzle systems.
Steps in CIP process:
a) Flushing in order to eliminate residues
b) Alkaline cleaning operations: alkaline detergents dissolved fat and proteins and cleaning where hard deposits have occurred.
c) Intermediate water rinse
d) Acidic cleaning operation: For neutralizing the caustic remaining on the surface of the plant, the acidic detergents remove the mineral deposits in the equipment especially (warm areas like the pasteurizer).
e) Final water rinse: Cold water purges out the residual acid solution
CIP is a closed system where recirculating cleaning solution is applied (often with nozzles) that cleans rinses and sanitizes equipment. The CIP system is usually automatically controlled and the cleaning sequences are given optimum timing for the efficient cleaning of all the parts of the plants.
4) Backwash Water Treatment Units: Periodic backwashing is performed to remove filtered materials from the membrane surface. A water only backwash back flushes the surge of filter water through the membrane to lift the sediment from the surface and flush it to waste. Some manufacturers use chemical backwashing or high pressure “air ram” backwashing. However the goal is the same regardless of the method used, To remove the solids from the membrane by lifting dirt away. Backwashing is done in a periodic manner to prevent any fouling which might occur if significant pressure were allowed to build up between backwashes.
5) Flash Mixer and Flocculator systems : Flash mix and Flocculation refers to the process in which fine particulates are clumped together into a larger “flocculated’ particles. The floc may then float on the top of the liquid, settle to the bottom of the liquid or depending on its characteristics remain suspended. Depending on the results the solids can be separated by the use of sedimentation clarifier, a flotation system or the filtration system.
Flocculation is widely used and applicable in sewage treatment systems, storm water treatment and the treatment of other industrial wastewater streams, as well as purification of drinking water.
Effluent from the equalization tank shall be pumped to the primary clarifier through the flash mixer where in optimum amounts coagulants (Lime, Alum and poly electrolyte) shall be added and the flash mixer where in the coagulant is mixed with the effluent with the high speed stirring system in a mechanically controlled manner for the solids to be settled as sludge in the clarifier. Ferrous sulfate solution and lime solution will be dozed in the raw waste water for the purpose of removal of color.
6) Tube Settler: It is a treatment in the water treatment technology in which clear, safe, drinking water from low quality water sources are treated. It is capable of purifying the most difficult type of raw water. They are particularly suitable for surface waters with high and variable contaminant loadings. They excel in treatment of cold water with high levels of turbidity, iron and manganese.
Working of Tube Settler: A Coagulant is added to the raw water to precipitate dissolved contaminants and encourage suspended particles grouped together in term of “Floccs”. Gentle agitation in the flocculation zone encourages the floccs to grow and they are then removed by settling within the clarification zone. The accumulated solids are removed hydraulically from the clarifier floor and the clarified water passes to the filter for final polishing. Solids accumulated within the filter are periodically removed by automatically controlled water or air/water backwashing.
7) Sludge Thickener: Waste water treatment plants use the thickening device to increase the solids concentration at the end of the particular processes step within the activated sludge processes. Thickening of the sludge increases its solid content and reduces the volume of the free water minimizing the unit load on the downstream process such as digestion and dewatering.
The most commonly used thickening processes is the gravity thickening, dissolved air floatation, gravity belt thickening and the rotary drum thickening. Centrifuge thickening is also most common. The type of thickening that is selected is determined by the waste water plant, its physical constraints and the downstream process.
8) Centrifuge: A centrifuge applies the centrifugal force to sludge to separate solids from liquids. Centrifuges are typically used to thicken primary sludge, by mixing with waste activated sludge (WAS) to create a thickened sludge or dewatering primary sludge to create solid sludge (cake). The cake must be disposed of by the waste water treatment plant.
9) Centrate Transfer System: When liquid sludge is produced, further treatment may be required to make it for disposal. Typically sludge’s are thickened (dewatered) to reduce the volume transported offsite for disposal. There is no process to completely eliminate the process of the need to dispose of the Bio solids. Sewage treatment plants have dewatering facilities that use large centrifuges along with the addition of chemicals such as polymer to further remove liquid from sludge. The removed fluid called “Centrate” is reintroduced into the wastewater process. The product that is left is called “Cake” that is picked by the companies to be converted into fertilizer pellets.
Process Flow Diagram:
Brief Process Description:
The Treated sewage from existing sewage treatment plants shall be collected in proposed collection tank. Then the combined water shall be pumped to the Gravity Dual Media Filter for Particle Filtration. It consists of pebbles, graded sand media and anthracite for removal of suspended solids and trace organics etc. The filtrate shall be collected in Filtrate Collection Tank and it shall be pumped to Micro Filtration System to remove very fine colloidal particles, & bacteria etc.
The treated water from micro filtration shall be collected in MF filtrate collection tank & fed to micron filter by micron filter feed pump for removal of fine suspended solids and turbidity.
The filtered water from micro filtration shall be further treated by Reverse osmosis (RO) System for removal of dissolved salts other minerals. RO plant consists of micron filter, MF feed pump, RO High Pressure pump and Reverse Osmosis modules (Stage I & II). The chemical dosing systems like Antiscalant, pH correction Solution, acid & alkali are provided in the system.
The RO permeate water shall be collected in permeate collection tank and the quality of water will be very rich and can be used for industrial process requirements. The reject water shall be collected separately and disposed to sea.
The backwash water from the gravity dual media filter, cleaning & rinsing water from the MF & RO system shall be collected in backwash water collection tank and treated by physio-chemical treatment and recycled back to collection tank.
iii)Conveyance of Tertiary Treated Water Form TTP location to Industries:
The treated water from the TTP plant shall be pumped to the industries through piped network with flow monitoring systems.
Benefits of waste water recycling plant:
- Sewage recycling is the best renewable / reliable resource at present scarcity.
- Pollutants disposal to the sea / natural drain can be minimized.
- The potable water supplied to the industries can be saved by replacing tertiary treated sewage and saved water can be supplied to general public.
- The cost of buying this treated water is very much cheaper than the sea water desalination.
- Due to increase in water demand for the forth coming years, the consistent supply of water can be assured to bulk consumers.
Some of the potential buyers of the recycled water:
1) Visakhapatnam Steel Plant
2) Visakhapatnam Port Trust
3) Essar Steel
4) Hindustan Petroleum Corporation Limited (HPCL)
Conclusion: The presence of the sewage treatment plant has a profound effect on the conservation of natural resources as it prevents the release of effluents into the atmosphere in an irresponsible manner.
As a part of the curriculum for the completion PG Diploma in Environmental Studies 2013-2014. We were taken for a field visit to Pollution Control Board (Visakhapatnam) Steel Plant on 25th March2014
POLLUTION CONTROL BOARD (VISAKHAPATNAM)
FIELD VISIT TO POLLUTION CONTROL BOARD ON 25ST MARCH2014
The Andhra Pradesh Pollution control Board (APPCB) is a statutory authority responsible to implement laws and rules on polluting entities within the jurisdiction of the state of Andhra Pradesh. It is initially set up to implement the provisions of the water (prevention and control of pollution) Act, 1974.
It was later entrusted to implement other rules relating to the environment. As stated below:
1) Water Act
2) Air Act
3) Water Cess Act
4) Environment Protection act
5) Hazardous Waste (Management and Handling) Rules
6) Bio-Medical Waste (Management and Handling) Rules
7) Municipal Solid Waste (Management and Handling) Rules
8) Plastic Manufacture Sale and Usage Rules
9) Batteries (Management and Handling) Rules
10)Manufacture, import and storage of Hazardous Chemicals-Rules
Apart from the above based on the category of the industry and per unit of the operation the environmental standards are set. For the Industries like Aluminum, Asbestos, Battery manufacturing industries etc certain guidelines and standard are defined.
For the calculation per unit of operation the parameters taken are Ambient Air Quality, Noise etc are taken in to consideration.
Our visit to the APPCB at Vizag was commenced with the introduction with Mr. Butchi Babu who was instrumental is taking us around the laboratory for introducing us to the equipment in which the testing and analysis takes place.
The lab equipment and their functionalities are listed as below
1) Atomic Absorption Spectrometer (AAS): It is an instrument used for spectroanalytical procedure for quantitative determination of chemical elements using the absorption of Optical radiation (light) by the free atoms in the gaseous state.
In the analytical chemistry it is used for determining particular element in a sample to be analyzed. AAS can be used to determine over 70 elements in a solution or directly in solid samples that are used in pharmacology, toxicology and Bio-Physical research.
Apart from the usage in Clinical and Pharmaceutical analysis AAS is used for water analysis for analyzing the water for the metal content.
The analysis of water through the Atomic Absorption (AA) method is the oldest and the most well established methods. It dates back to the time when specific salts in the chemical sample gave characteristic colors to the luminous flame. It is the most popular methods for the use in element analysis. It uses the absorption light to measure the concentration of the gas-phase atoms. Since the samples are usually liquids and solids, the analyte atoms or ions must be vaporized in a flame or graphite furnace. The flame is used to dissolve and vaporize the analyte. This technique is called the Flame Atomic Absorption Spectroscopy (FAA).
If the graphite furnace is used the technique is called the Graphite Furnace Atomic Absorption (GFAA) it is also called electrothermal atomic absorption spectroscopy.
Depending on the metal there is a prescribed method number and the Atomic Absorption Method used for Analysis.
Elements like Zn, Pb, Cu, Ni, Ca, Mg, Fe and Mn are determined routinely in the water samples using the atomic absorption spectroscopy. Sodium(Na) and Potassium (K) are determined by flame emissions.
During the field trip to the APPCB we were introduces to the fully computerized Atomic Absorption spectrometer of the Avanta Make. Its features include
1) A fully Motorized Turret
2) Automatic lamp optimization and Peaking
3) Automatic wavelength setting
4) Automatic Slit wide setting with 0.1 to 2.0 nm in 0.1nm increments
5) Automatic Slit height setting with 0.1 to 2.0 nm in 0.1nm increments
6) Hyper-Pulse background correction
7) USB Communication
8) Runs on Windows Vista Operating System
9) Assymetric Modulation
10)Narrow Beam All Reflective Optics
11)Optional Coded Lamp Recognition
12)Optional Automatic Burner Rotation
13)Optional Built-in 10V super lamp power supply for 1 or 4 lamps
The technique make use of the fact that the neutral or the ground state atoms of an element can absorb electromagnetic radiation over a series of very narrow, sharply defined wavelength. The sample solution is converted into fine mist into a flame where it is converted into vapor. Most of the atoms remain in ground state and are capable of absorbing light of suitable wavelength. The discrete radiation is supplied by a hollow cathode lamp, which is a sharp line source, consisting of a cathode containing the element to be determined with the tungsten Anode. The line characteristic of the element are emitted by the hollow cathode and passes through the flame and are absorbed by the atomic vapor, since only the test element can absorb this radiation, the method becomes specific.
The samples are collected and the water is used for sampling purpose. The catridges in the turret are changes as per the metal to be tested in the water. In the associated system the user logs into the system and necessary settings are made.
The principle of Atomic Absorption Spectrometer is as below
The total number of light absorbed is mathematically computed by the formula
The source of radiation is as follows:
1) Hollow Cathode Lamp (HCL)
2) Electrode Less Discharge Lamp (EDL)
The initial step is to prepare the sample for testing. The preparation of sample involves the below steps:
1) Weighing of Samples
2) Dissolution in the appropriate solvent or digestion using different techniques
3) Dilution of Sample if necessary
The sample employed for the Atomic Absorption Spectroscopy in the laboratory is placed in one of the following categories
1) Aqueous Solutions
2) Organic Solutions
3) Inorganic Solutions
4) Organic Solids
The Lab in APPCB uses the Aqueous Solution category for the water analysis
Aqueous Solution: A little preparation is required with this sample. The testing samples include raw and treated water.
Techniques used for Sample preparations:
1) Wet ashing or wet digestion: Inorganic Samples that are un-dissolved in aqueous solvent are treated with acids like perchloric acid, HCL, HNO3 for the digestion of complex silicates for obtaining clean liquid with no single element being removed.
The other laboratory equipment available for testing purpose is the Gas Chromatography
Gas Chromatography (GC)
It is a type of chromatography used in analytical chemistry for separating and analyzing of the compounds that can be vaporized and decomposed. It is used to test the purity of a particular substance. It is used to separate the components of a certain mixture. It helps in identifying a compound. In preparative chromatography Gas Chromatography is used to prepare pure compounds from a mixture.
In GC the moving gas which is a carrier gas, is usually a gas like helium, nitrogen, argon, hydrogen and air, and gas like Nitrogen is non reactive in the mobile phase. In the stationary phase the microscopic layer of the liquid or polymer or an inert solid support, inside a piece of glass or the metal tubing is called the column. Homage or the fractional column is used in distillation. The instrument used to perform the gas chromatography is called the gas chromatograph or the “Aerograph” or “Gas Separator”.
Analysis of Gas Chromatograph
It is used for analyzing chemicals in a complex sample. The series of steps used in the analysis are as follows:
1) Different chemical constituents of the sample are passed through the narrow tube called the Column.
2) The chemical constituents of the sample pass in a gas stream (carrier gas, mobile phase) at different rates depending on the various chemical and the physical properties and their interaction with the different column filling in the stationary phase.
3) When the chemicals exit at the end of the column they are detected and identified electronically.
4) The stationary phase in the column separates different components causing each of the components to exit at different times. (This time is called the retention time. The retention time can be altered using the length of the column, carrier gas flow rate and the temperature )
Physical Components of Gas Chromatograph
1) Auto samplers: Auto samplers provide the means to introduce the sample automatically to the inlets. Manual insertion of the sample is possible but no longer common. Automatic insertion produces better reproducibility and time optimization.
2) Inlet: The column inlet (injector) provides the means to introduce the sample into the continuous flow of carrier gas. The inlet is a piece of hardware attached to the column head
3) Detectors: The commonly used detector is the flame ionization detector (FID) and the thermal conductivity detector (TCD). Both are sensitive to a wide range of components and both work over a range of concentrations. The TCD is universal and is used to detect any component other than the carrier gas. FID is sensitive to hydrocarbons and cannot detect water and is more receptive compare to TCD. Both the detectors are robust and TCD is non destructive.
The method is the process in which the GC operates for a given analysis. Method conditions are a process which determines in which conditions are adequate or ideal for the analysis to take place.
The conditions can be varied to accommodate the required analysis of inlet temperature, detector temperature, column temperature, the temperature program, carrier gas and the carrier gas flow rates, the column gas flow rates, the columns stationary phase, diameter and length, inlet type, flow rates, sample size and injection technique, Depending on the detector installed on the GC, there may be a number of detector conditions that can also vary. Some GC’s also include valves which can change the route of the sample and the carrier flow. The timing of opening and closing of these valves are important.
Maintenance of Air Quality
Air quality is important simply because we can’t avoid breathing the air around us. The average adult breathes in about 20 cubic meters, or 20,000 liters of air a day. Other planets have sunlight, but only our earth has air and water. Without all of these there would be no life. A diverse community of plant and animal life has thrived on this planet for millions of years, sustained by the sun and supported by the soil, water and air.
The air is made up of nitrogen and oxygen, with traces of other gases such as carbon dioxide, plus minute particles like dust. Although clean air should be freely available to all plant and animal life, humans have been gradually polluting it, putting their health at risk and the well-being of the earth itself.
Air pollutants come mainly from discharge of gases and particles from industry, Biomass consumption and motor vehicles.
Rapid industrial and economic growth of the developing countries in Asia has increased urbanization and population pressure on local and national governments to keep pace with urban environmental management systems to meet the needs of the expanding cities with numerous parameters for management. Air pollution abatement strategies, solid waste management plans, supply of water and control of wastewater and sewerage systems are the essentials of environmental management. In this energy plays a crucial role in all development plans to enable a livable city. Therefore, urban governance is challenged with the rapid globalization and the need to provide basic amenities to the population.
APPCB is assessing the ambient air quality in the state. A monitoring network with 60 ambient air quality-monitoring stations throughout the state are placed to assess the changes in air quality. In addition to it in Hyderabad continuous ambient air quality monitoring station has been installed. Based on the results of these monitoring stations, the government of A.P has taken preventive measures to control air pollution from different sources. APPCB is monitoring the point source emissions regularly and directions to install / upgrade air pollution control equipment are given to the industries that are exceeding the standards.
Objective of APPCB in Visakhapatnam in Controlling the Air Quality
- To determine the status and trends of ambient air quality
- To ascertain whether the ambient air quality are maintained
- To identify non attainment cities
- To Obtain the knowledge and understanding necessary for developing preventive and corrective measures
Quality assurance control of air
Since important decisions have to be taken based on the results of CPCB through air quality monitoring program on various pollution control activities the CPCB official take the following steps to execute the same.
- Officials of the CPCB regularly visit the monitoring stations and monitoring laboratories to ensure proper methodologies for sampling and analysis. The findings are communicated to respective monitoring agencies.
- CPCB conducts reviews with monitoring agencies to conduct to plan the future course action and their remedial measures
- CPCB regularly conducts the analytical quality control and exercises during the Ring test Facility to evaluate the performance of different laboratories
- CPCB conducts the training program on ambient air quality monitoring program with an objective to improve the quality of data generated under National Air Quality Monitoring Program (NAMP). Training is provided to the field monitoring staff involved in NAMP. Training is provided in measuring Sulphur Dioxide (SO2), Nitrogen Dioxide (NO2), Respirable Suspended Particulate Matter(RSPM) and Suspended Particulate Matter (SPM)
Certain guidelines have been defined by CPCB for carrying out ambient air control monitoring.
- Site selection criteria
- Quality assurance with quality control in Air quality monitoring
- Type of pollutants to be monitored in the city
- Frequency and duration of monitoring
- Data reporting and compilation procedures
- Measurement methods of various air pollutions
The quality of the data is important. In order to provide actual quality of data, regular calibration, service and repair of field device is a must. Realizing this, CPCB has initiated a project called the calibration and Evaluation of Ambient Air Quality monitoring stations in India.
To monitor the quality of air, the PCB in Vizag is using the instrument called “Respirable Dust Sampler”
There basically three categories of dust Respirable, Thoracic and inhalable (inspirable). Respirable dust particles are under 10microns in diameter. Thoracic dust particles are under 25microns in diameter and inhalable dust particles are under 100microns in diameter. The dust sampling methods varies upon the type of dust to be evaluated.
The Respirable dust sampler used by the PCB in Vizag is used for the estimation of total suspended particulate matter including Respirable suspended particulate.
U-V Visible Spectrometer: It is used in the estimation and the analysis of particles like Sulphate, Fluoride, Phosphate, Nitrates, Chromium+6, Oxides of Nitrogen and Oxides of Sulphur.
It refers to the absorption spectroscopy or the reflectance spectroscopy in the ultraviolet visible spectral region. It uses light in the near in the visible and adjacent in the near UV and near Infra Red (NIR) ranges. The absorption or the reflectance in the visible range directly affects the perceived color of the chemicals involved. In this region the electronic spectrum undergoes electronic transition. This technique is complimentary to fluorescence spectroscopy. The fluorescence deals with the transitions in the ground state, while absorption measures transitions measures transitions from the ground state to the excited state.
The instrument used in the U.V Spectroscopy is the Spectrometer. It measures the intensity of the light passing through a sample (I) and compares the intensity of light before passing through the Sample (). The ratio is called the transmittance and is usually expressed as the percentage (%T). The absorption A is based on the transmittance:
The UV –Visible can also be used to configure measured reflectance. In this case the spectrometer measures the intensity of light reflected from a sample () and compares it to the light reflected from the reference material () (like the white tile). The ratio is called the reflectance, and is usually expressed as a percentage (%R).
Specific Ion Analyzer: It is used to estimate the Cations like Sodium, Potassium, Calcium, and Anions like Chloride, Fluorine, and Sulphate etc.
It converts the activity of a specific ion dissolved in a solution into an electric potential, which can be measured by a voltmeter or pH meter. The voltage is theoretically dependent on the logarithm of the ionic activity. Sensing the part of the electrode is usually made of an ion specific membrane along with a reference electrode.
In the application perspective the electrode wire is connected to one terminal of the Galvanometer or pH meter, the other terminal is connected to the reference electrode and both electrodes are immersed in the solution and tested. The passage of the ion through the vinyl via the carrier or channel creates an electric current which registers in the Galvanometer, by calibrating against the standard solutions of varying concentration; the ionic concentration in the testing solution can be estimated from the galvanometer reading.
The most serious problem limiting the use of Ion specific analyzer is no membrane is ion specific. All the membranes are sensitive to other ions having similar physical properties. Most of these inferences are weak enough to be ignored. But in most of the cases the electrode may actually more sensitive to the interfering ion than the desired ion, requiring that the interfering ion may be present on relatively low concentrations or entirely absent. The Nitrate electrode has various interferences i.e perchlorate, iodide, chloride and sulfate. At pH 12-13 any ammonium ion in the sample is converted to ammonia gas and is ultimately detected by the electrode.
Using the above instruments the APPCB at Vizag collects various samples from the industries at periodic intervals or when there is a complaint raised on the same. The samples are collected and tested for the related polluting data.
Conclusion: The pollution control board in Visakhapatnam is doing an incredible job in monitoring the polluting industries. Periodic checks are being conducted by taking samples from these industries to ascertain the level of pollutants these industries are emitting. Based on these readings necessary action will be initiated or future course of action will be planned for reducing the output of emissions.