Water is a natural resource which covers 71 per centum of the earth’s surface. Around 97.5 per centum of the entire H2O in the planet is saline. Staying 2.5 per centum is freshwater and contained in lakes, rivers and frozen as a glaciers and the polar ice caps. Around 68.6 per centum of the fresh H2O on Earth is in glaciers and polar ice caps. Rest of the fresh H2O is in the land H2O and surface H2O in 30.1 per centum and 1.3 per centum severally.
Chiefly surface H2O is utilised for twenty-four hours to twenty-four hours intents such as irrigation, industrial and domestic ingestions, straight or after holding a intervention procedure. But accessible sum is about 20 per centum of the surface H2O that is about 0.0065 per centum of the entire H2O contained in the planet [ 1 ] . Rest of the sum consists as an atmospheric H2O, biological H2O, dirt wet, ice and snow. Figure 1.1 illustrates the distribution of H2O in the planet [ 1 ] . Therefore, it is an indispensable to carryout proper direction procedure to keep the limited surface H2O in healthy mode because H2O is extremely vulnerable to pollution.
There are many causes of H2O pollution viz. , direct beginnings and indirect beginnings. Direct beginnings ( point beginnings ) include outflowing discharge from industries, refineries, waste intervention workss etc. that emit unwanted affair into H2O beginnings and it is more seeable to the exterior. Indirect beginnings ( non point beginnings ) include contaminations that enter H2O systems through soil/groundwater systems and from the ambiance via rain H2O. Dirts and land Waterss may incorporate agrochemicals ( fertilisers, pesticides, etc. ) , industrial wastes and atmospheric contaminations, which derived from anthropogenetic patterns such as gas emanations from cars, mills etc. ; mix with the H2O and fall down as acerb rain to the land and it non much seeable to foreigners. However, both pollution methods may take to cut down the quality of the H2O below the recognized criterions.
1.1Water Quality Standards
Water quality is a term which is used to depict the chemical, physical and biological composing of H2O to asses basal line information on H2O safety. There is no individual step that constitutes the quality of the H2O. Under the ideal conditions, it must be free from disease-causing beings, harmful chemical substances, and radioactive affair while free from obnoxious coloring material or smell. Dissolved minerals and other chemical components are good to human wellness and it may assist to better the gustatory sensation of the H2O if they present in World Health Organization ( WHO ) recommended degrees. However, most of them have damaging wellness effects if they present above the recommended degrees. Governments define the guidelines for maximal allowable degree of parametric quantities in H2O which is used for different intent, such as imbibing, irrigation and industrial intents, etc [ 2 ] . For case, H2O which is suited for imbibing, can used for irrigation intent without any issue, but H2O, used for irrigation is non suited for imbibing at all the times.
The criterion of imbibing H2O is implemented to guarantee that it does non ensue in any important wellness hazard to the consumer over a life-time of ingestion. Water quality criterions for industries are defined to guarantee the quality of merchandises. To guarantee the stableness of the aquatic environment, governments define the tolerance bounds for the discharge of industrial and domestic waste H2O into the environment [ 5 ] .
Different states have selected a list of parametric quantities to specify the appropriate values with fulfilling the local conditions and tolerance bounds for each parametric quantity. In other words the criterions may somewhat alter from state to state. The European Drinking Water Directive [ 8 ] and the United States Environmental Protection Agency ( EPA ) [ 6 ] specify the criterions for imbibing H2O sing their local conditions.
For states have n’t decently defined guideline and criterions to mensurate the quality of the H2O, the World Health Organization provides guidelines and criterions to guarantee safety of imbibing H2O.
In Sri Lanka, the ordinance for each major pollutant has been listed in the National Environmental Act No. 47 of 1980 ( which several alterations ) and Sri Lanka Standards Institute ( SLSI ) defines the maximal allowable concentration of physical and chemical parametric quantity values under the criterion of “ Sri Lanka Standards for drinkable H2O ( SLS 614: 1983 ) ” [ 3 ] .
1.2Water Quality Parameters
In general perceptual experience, people measure the quality of H2O by utilizing the seeable factors ( coloring material, smell, gustatory sensation etc. ) and merely think the pollution position of a H2O organic structure. In fact, H2O quality is a really complex topic, because H2O is combined with the ecology of the Earth. Therefore, a set of internationally accepted criterions are defined to measure H2O quality parametric quantities and the values which can be seen in the lower limit or upper limit degrees related to imbibing, industrial, agricultural intents, established for the benefit of ecosystems [ 2 ] . Water quality parametric quantities are divided into three classs such as physical, chemical and biological.
Behavioral forms of the H2O quality parametric quantities are really complex and it often fluctuate harmonizing to many different natural factors such as climatic, structural, geochemical and size of the water-body etc. and anthropogenetic factors such as land usage patterns and domestic and industrial waste. Those fluctuations occur as diurnal ( 24-hour period ) , seasonal and random fluctuations. To guarantee the healthy H2O beginning it is indispensable to concern the behaviour of the each and every parametric quantity
There are more than 100 H2O quality parametric quantities identified [ 4 ] under the three classs such as physical, chemical and biological. Most of the trial instances are extremely expensive and clip consuming and non to accessible to all parts of the universe. Harmonizing to the demand most of import H2O quality parametric quantities under the three classs are selected for this survey [ 2 ] .
1.3Present Water Quality Monitoring Methods
At present, there are four methods chiefly applied to supervise the quality of the H2O beginnings and each method has its ain advantages and disadvantages [ 9 ] .
1.3.1Grab Sampling Method
In this method, H2O samples are collected manually and so preserved utilizing an appropriate method. Finally, they are transported back to the lab to analyse. Although manual sampling and research lab analysis is traditional, still it is used as a precise appraisal technique for qualitative and quantitative analysis of chemical and biological contaminations and is the widely used method in Sri Lanka [ 10 ] . Though it is able to originate with a less capital investing, this method is hard or unable to track H2O quality parametric quantities for long-run period in a uninterrupted mode, particularly under the rough environment conditions such as torrential rainfall and hurricanes. Furthermore, it causes a figure ofdisadvantages such as high operation cost per sample, considerable hold is sample analysis, high human mistakes and hard to carry on it in the nighttime [ 9 ] . Therefore this method is ideal for less frequent, independent informations roll uping intent but non suited for multi discrepancy and uninterrupted monitoring intent.
1.3.2Automated and Continuous Monitoring Method
To supervise H2O quality parametric quantities, automated monitoring system is used to supervise the behaviour of the H2O organic structure from a distant location. Wireless detector web engineering is widely used to enter parametric quantities in real-time mode. Using this method, it is possible to roll up the informations with including the of import clime factors which imparked to fluctuate the H2O quality parametric quantities without losing episodic events ( with including the diurnal fluctuations ) . This type of informations set is utile to pattern the behaviour of the H2O beginnings and to make the prediction. And besides, it enables the appraisals of the current province of H2O measure and its variableness in infinite and clip. Other biggest advantage are, able to place the random fluctuations which occur in unpredictable events and able to supply exigency messages instantly on a 24-hour footing. Therefore a real-time monitoring technique to mensurate the basic physico–chemical H2O quality parametric quantities is indispensable to heighten supervising procedure of the quality of H2O and furthermore it is helpful to trip early warnings with enabling timely actions to originate appropriate intervention under unexpected state of affairs. Thought initial investing is high, it is easy to deploy, spread out, maintain. It suits more to supervise behaviour of the environment which changes quickly over the infinite and clip, in real-time mode and roll up the parametric quantity values with a minimum operation cost [ 9-12 ] .
1.3.3Remote Sensing Method
Remote detection is a technique that used to obtain information about objects through the detectors which mounted in orbiters or aircraft. In the distant detection method, detectors have no physical contact with the objects of probe. Detectors collect informations by observing the energy that reflect or emit ( electromagnetic radiation, including seeable visible radiation and unseeable thermal infrared ) from natural and man-made objects on the Earth. In H2O quality monitoring intent, remote detection is specifically used to supervise H2O quality parametric quantity such as temperature, suspended affair, phytoplankton, turbidness, and dissolved organic affair etc. Natural images are available on a day-to-day footing and demand considerable excess processing plants to pull out the parametric quantity values. But truth is lower than the other methods. This is the most suited method to supervise broad countries and non much suited to feel informations in deeper beds. Another restriction of distant detection is that the frequence and hold of informations depend on the satellite’s orbit. Atmospheric factors, distance of the orbiters, sensitiveness of the detector etc. impact the truth of the readings [ 9,13 ] .
1.3.4Using Sensitive Aquatic Organisms
Qualitative rating of the presence of toxicant substances in H2O organic structures is measured utilizing the sensitiveness of some aquatic beings ( E.g. : Fish, Beach Louse, algae and zooplankton etc. ) [ 9, epa ] supervising the behaviour of them in different H2O environments. Still it is used as a crude method but unable to anticipate as a high truth method in H2O quality monitoring procedure [ 9 ] .
1.4Importance of the Study
Sri Lanka is a state which is rich in H2O beginnings such as rivers, lakes, reservoir and perennial armored combat vehicles crossing the full state. Due to the anthropogenetic activities and natural incidents H2O beginnings become polluted. Not merely that eutrophication of fresh waters by anthropogenetic activities is leads to impairment of the quality of the H2O and frequently class to proliferation of blue-green algae ( blue–green algae ) . Most of the blue-green algae generate toxins which impact on human wellness and alter the H2O chemical science every bit good. Thus provide safe imbibing H2O is a planetary challenge. Therefore, it is a primary duty of the governments to supervise the quality of H2O continuously to keep acceptable H2O quality criterions of imbibing H2O beginnings to rescuer the peoples.
In Sri Lanka,in-situandinvitroreadings are measured manually utilizing sample aggregation methods. Thus these methods would non accommodate obtaining uninterrupted informations for a twenty-four hours or a longer period because of the high operation cost ( pass more clip, high chief power, transit cost etc. ) Therefore, trying frequence is low. A real-time technique to mensurate the basic parametric quantities will heighten vastly the monitoring procedure of the quality of H2O. Most developed states use radio detector web engineering to spread out the procedure of H2O quality supervising with low operation cost.
Due to high capital investing, still Sri Lanka is unable to present radio detector web engineering to supervise H2O quality parametric quantities. Under these fortunes, we are unable to roll up accurate multivariate H2O quality informations set under the different conditions, clime, and geographical conditions. This type of informations set gives more advantages for research workers to place behaviour of the H2O organic structure and prediction. This undertaking is focused to present a low cost real-time H2O quality monitoring system to mensurate the selected H2O quality parametric quantities.
1.5Selected Water Quality Parameters
Sing the of import of the parametric quantities and based on the demand, the pH conduction, dissolved O and temperature parametric quantities are selected for implementing the procedure in this survey.
pH is a term used to bespeak the alkalinity or sourness of a H2O sample. It is one of the most common and of import chemical parametric quantities in H2O quality appraisal. The pH graduated table runing by and large from 0 ( really acidic ) to 14 ( really basic ) , with 7 being impersonal in natural Waterss and most natural H2O contains weak acids and bases. The fluctuation of the pH of H2O is extremely depending on the buffer capacity of the sample. Variation of the pH affect to the chemical and biological procedures in the aquatic environment. Most aquatic animate beings and workss are unable to last under the conditions of high sourness ( below the pH 4 ) and the alkalinity ( above the pH 10 ) [ 4 ] . The fluctuation of the pH is extremely consequence to the H2O chemical science. Heavy metals such as Cd, lead, Cr, aluminium, Fe etc are fade outing easy in acidic H2O ( lower pH ) and such H2O go much more toxic. As a consequence, aquatic animate beings and worlds who use such H2O for imbibing intent may confront many wellness issuers. Therefore, pH is really of import factor for healthy H2O. [ 4 ] [ 6 ] .
1.5.2Electrical Conductivity ( EC )
EC is mensurating the ability of H2O to go through electrical current idea H2O with the support of positive ( cations ) and negative ( anions ) ions in the solution. Distilled H2O is a hapless music director of electricity. Dissolved inorganic substances such as chloride, nitrate, sulphate, and phosphate anions ( with negative charge ) or Na, Mg, Ca, Fe, and aluminium cations ( with positive charge ) are classs to increases the EC of the H2O. Proportionate to the increase to the conduction, salt additions. In other words, high conduction indicates that there are many ions dissolved in the H2O. EC gives a unsmooth index of dissolved mineral content of the H2O.
Aquatic animate beings and workss have an ability to last in certain tolerate scope of salt. But Outside of that scope, it may be negatively affected to the aquatic system or animate beings and workss may decease ; means salt straight affects the aquatic life. For imbibing H2O, allowable degree of EC is 750 µS/cm [ SLS 614 ] otherwise, it may class for the wellness issues. In agricultural position, it effects to the works growing and harvests. In industrial position, it may detrimentally effects to the machineries ‘ and the quality of the merchandises [ 4-6 ] .
1.5.3Dissolved Oxygen Level
Dissolved O ( DO ) is one of the chief H2O quality parametric quantities that play a critical function in aquatic life. Aquatic beings such as fish, invertebrates, bacteriums, and submerged workss use DO for their respiration. Not merely the biological procedure but besides DO degree impact to the oxidation-reduction potency ( ORP ) of H2O. Oxygen gets into H2O by diffusion from the environing atmosphere by aeration ( rapid motion ) , and as a merchandise of photosynthesis of workss inside the H2O organic structures. When dissolved O degrees decline certain sensitive animate beings may travel off, weaken, or decease [ 6 ] . Particularly DO degree is straight affect to the balance of the aquatic environment.
Temperature is one of the of import physical appraisal parametric quantities of H2O quality ; it measures how much heat nowadays in the H2O. In general, temperature of the H2O organic structure varies with the latitude, height, seasonal, clip of twenty-four hours, air circulation and the deepness of the H2O organic structure. Water has a great heat capacity to keep energy. Therefore a big sum of energy is indispensable to raise the temperature of H2O in one unit, in other words when temperature is raised, it will take a long continuance to stabilise. In a natural phenomenon, ground-water normally maintains a reasonably changeless temperature. Therefore the natural fluctuation of the temperature may non act in a harmful mode for the aquatic environment. But influence of the anthropogenetic activities temperature of the H2O organic structure may be additions in unnatural manner. Water temperature has an influence to organisms life in the H2O and it may consequence on modifiers of physical, chemical and biological processers of the H2O organic structure. Therefore H2O temperature is defined as a one of the major physical parametric quantity parametric quantity in the H2O quality appraisal procedure and it is indispensable to enter temperature as unmoved measuring at the clip of roll uping H2O samples [ 6 ] .
1.6Aims of the Research
The aims of this survey are,
- To plan and develop a individual bit solution to interface transducers to web.
- To plan and develop a low cost, real-time radio detector web to mensurate selected H2O quality parametric quantities in dynamic environment.
- To build a laboratory degree proof-of-concept utilizing the developed detector nodes.
- M.D.R. Perera, R.G.N. Meegama and M.K. Jayananda, “Single Chip Solution with 1-Wire Communication Protocol to Interface Digital Transducers to Sensor Networks” ,36ThursdayAsia Pacific Advanced Networking ( APAN ) Research Group Workshop, Daejong, Korea, 2013.
- M.D.R. Perera, R.G.N. Meegama and M.K. Jayananda, “A Single-Chip Solution for Interfacing Transducers to Sensor Networks Using FPGAs” ,8ThursdayIEEE International Conference on Computer Science & A ; Education, 2013, pp. 201.
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