Monday, 16 May 2016

Process of Wastewater Treatment Plant


Wastewater enters the treatment plant
First it goes through a fine screen, next to aerated grit chamber, and then enters the primary clarifier. Sludge settled in the primary clarifier is sent to the fermenters and then to digesters.
After the primary treatment, wastewater flows into (BNR) bioreactors.
The activated sludge is separated in the following secondary clarifier. The clear effluent flows into Ultraviolet (UV), then to River. Settled activated sludge in the secondary clarifier is pumped back to BNR.
Excess sludge is pumped into the dissolved air floatation (DAF) unit for thickening.
Wastewater is collected in sanitary sewers (a complex network of underground pipes). Upon reaching the treatment plant, the wastewater flows through a series of treatment processes which remove the wastes from the water. Each step the water becomes cleaner.
Grit Removal

In the grit chamber, heavy particles, such as a small stones, eggs shells, and coffee grounds settle to the bottom and are removed. These abrasive materials can damage pumps and cause equipment to fail prematurely the grit is removed and washed in the grit classifier before it is properly disposed.

Preliminary Treatment

Bar screens catch rags, sticks, plastic containers, and other objects floating in these large items are removed so that they do not clog pumps or interfere with other equipment process.
Primary sedimentation tank

In the primary sedimentation or "settling" tank, heavier solids are given time to sink to the bottom. These solids called "primary sludge" are sucked out of the bottom of the tank. They are sent to a digester for further treatment. Oil, grease, and other scum that float of the wastewater are skimmed off and may be sent to the digester.

The fermenters are large and closed tanks with a rotating stirring mechanism. Sludge is fermented to produce the volatile fatty acids (VFAs) .The residual sludge along with scum is pumped to the sludge digesters . The foul air also functions as a supplementary air supply for the bioreactors.
Dissolved air floating (DAF) tank

Waste activated sludge is thickened in dissolved air floatation (DAF) tank to reduce the volume of sludge.
Under the effect of air bubbles flowing upwards, the sludge solids are carried to surface and skimmed out.
Anaerobic Sludge Digester

Anaerobic digestion is biological process which break down a significant amount of organic solids in the sludge and at the same time produces methane gas
BNR bioreactors

The bioreactor is divided into several cells. In some cells, air/ oxygen is introduced through diffusers in removing pollutants such as BOD; while in other cells, no air is required to remove nitrogen and phosphorus .

The pollutants serve as the food source to maintain the metabolism of the microorganisms.

Ammonia is released into the atmosphere. Phosphorus becomes part of the plant biosolids (Sludge).

Secondary sedimentation tank

The sludge from the bioreactors flows to large circular clarifier. Settled activated sludge is then pumped back to the bioreactor and excess activated sludge is pumped to the dissolved air flotation.

Clarified supernatant from the secondary clarifiers flows through the Ultraviolet (UV) light disinfection unit, and then discharged to the River.

Sunday, 15 May 2016

Water Analysis : To Estimate The Amount Of Phosphorus Phosphate In The Given Sample

Phosphorus Occurs in natural waste water almost soley as phosphate. These are classified as orthophosphate condensed phosphate organically bound phosphate are applied as fertillizer to agricultural residential cultivated land are carried out to ground waters. This forms of phosphate arise from variety of sources. This occurs in solution in particle or detriters or in bodies of in aquatic organism.
Phosphorus is essential for growth of organism and can be nutrient that limits the primary productivity of body of water in instancy where phosphorus broth liniting nutrient or treated or treated water. Agricultural orannage certain industrial waste water. Test immunate photo lequane micro, macro organism in new senic quantity. Phosphate occurs in bottom sediment in biological sludge and both precipitated in organic forms incorporated into organic compound.
  1. Perchlorate acid digestion.
  2. Sulfuric acid, nitric acid digestion.
  3. Persulfate digestion method.
  1. Vandomollybdeum phosphoric acid method ( 1-2 mgp/1)
  2 Stannous chloride method (0.01-6 mgp/1)
  3. Ascorbic acid method (0.01-6mgp/1)
Ammonia molybled react in acid methium with orthophosphate to form hetropoly acid phosphomolybdic acid. That reduced intentionally colored molybdeum by ascorbic acid. This blue colored mixture at 880nm using spectrophotometer.
     1.  5N H2SO4
    -conc.H2SO4 (70ml)
    -Make final vol (500ml)
2.  Potassium ammonical titrate solution.
     -K(SO6O)C4H4O6.1/2H2O (1.375g)
     -D/W (500ml)
3. Ammonium molybled solution.
    -(NH4)6HO7O24 (20g)
    -D/W (500ml)
4. Ascorbic acid solution
     -Ascorbic acid (1.76g)
     -D/W (100ml) 
5. Combined reagent (always fresh)
             -  Solution 50ml
             -  Solution 5ml
             -  Solution 15ml
             -  Solution 30ml
Let all reagent before they are mixed in order given above. Mixed wel, After addition of reagent, If turbidity appear combine reagent. Shake it let it Shake for few minutes. This reagent stable for 4 hours.
 6. KH2PO4 (219.5mg) (1ml=500𝝁g)
     -D/W (100ml)
 7. Standerd phosphate solution.
    - stike solution (10ml)
    - D/W (90ml)
 8. Pipette, test tube
 9. Spectrophotmetric meter.
         -       Take different aliquote solution 1ml to 5ml.
         -       Don’t add phosphate in blank tube.
         -       Take three different unknown sample.
         -        Make final volume in 10ml D/W.
         -         Add 1.6 ml of combine reagent of all the tube.
         -         Incubate at room temperature for 15mins.
         -         Measure the absorbance of 800nm using spectrophotometer.
         -         Prepare standard graph of absorbance of standard sample against concentration of phosphate.
         -         Find out the Conc. Of unknown sample using std.curve.
PO4.P (𝝁gs)
PO4.P (ml)
D/W (ml)
Combined reagent (ml)
OD at 880nm

Water Analysis : To Estimate Amount of Nitrite Nitrogen In Given Water Sample

Nitrite is an intermediate oxidation state of nitrogen both in the oxidation of ammonia to nitrate & in the reduction of nitrate. Such oxidation & reduction may occur in waste water treatment, water distribution system & natural water. Nitrite can enter a supply system through it use as a corrosion inhibitor in industrial process water.
Nitrite is the actual etiological agent at methemoglobimia. Nitrous acid which is formed from nitrite in acidic solution can react with nitro samines , many of which are known to be carcinogens.
Nitrite is determined through formation of reddish purple azo dye produced at pH 2.0 to 2.5 by coupling diazotize sulphanilamine with N’ (1- napthyl) ethyl diamine dihydrochloride (NED). The applicable range of the method for photometric measurement is 10-10,000 micro gram NO2/l. Photometric measurement can be made in the range 5 to 50 µg N2/l, if a 5cm light path & a green color filter are used. Higher nitrite conc. Can be determined by diluting a sample with nitrite free D/W. The measurement is taken at 543nm using spectrophotometer.
  •  Nitrite frees D/W.
  • Water sample.
-          Drinking water &
-          Waste water

  • Color reagent.

        1. 85% phosphotic acid 100 ml. 
        2. Sulfonilamide 10 gm 
        3. Dissolved property in 800ml D/W. 
        4. NED hydrochloride 1 gm. 
        5.  Mix & final vol. 1000ml with D/W.
        6.  Solution is stable for 1 month.
  • When stored in dark bottle in refrigerator.   
  • Stock nitrite solution.  (NaNO2  1.232g)
 (1ml = 250 µg N)
-          D/w 1000 ml
-          Preserve with 1ml  CHCl3.
  • Intermediate nitrite solution.
-          Stock nitrite solution 50ml.
-          D/W  250 ml.
(1ml = 50 µg N)
  •  Standard (working) nitrite solution.
-          Intermediate nitrite solution 10ml.
-          Make final vol. 1000ml with D/W
(1ml  =  0.5 µg N)
-          Prepare fresh.
  •  Test tubes – 11
  • Pipettes  1 ml  & 10 ml
  •  Spectrophotometer & quates.
Take different aliquotes of std. nitrite solution form 0.2, 0.4,…….. 1 ml.
-          In blank do not add std. solution.
-          Prepare 3 aliquotes of unknown sample.
-          Add D/W in all tubes to make final vol. 10 ml.
-          Add 0.2 ml color reagent in all tubes.
-          Incubate all the tubes at room temp. For 10 min.
-          Take O.D. of all tubes at 543nm using blank as a reference.
-          Prepare a std. curve by plotting absorbance of std. against nitrite nitrogen (µ gms) of std. & find out conc. Of nitrite present in unknown sample.
-          Note down the result & give your conclusion.

Water Analysis : Estimation Of Nitrate Nitrogen In Given Water Sample

Nitrate is found only in small amounts in fresh domestic wastewater but in the effluent of nitrifying biological treatment plants nitrate may be found in concentration up to 30mg nitrate as nitrogen/L. It is essential nutrient for many photosynthetic autotrophs and in some cases has been identified as the growth-limiting nutrient. Generally 10mg nitrate nitrogen/L of drinking water is recommended to prevent disorder called methemoglobinemia in infants. Determination of nitrate nitrogen is difficult because of the relatively complex procedure. Although UV technique that measures the absorbance of nitrate at 220nm is suitable for measuring nitrate in wastewater.
This technique is useful for the screening of sample that has low organic content that is uncontaminated natural water and potable water supplies. The nitrate calibration curve follows Beer's Law up to 11 mgN/L. Measurement of UV absorbance at 220nm enables rapid determination of nitrate. Because dissolved organic matter may also absorb at 220nm and nitrate does not absorb at 275nm, a second measurement made at 275nm may be used to correct nitrate value.
·            Stock nitrate solution: Dissolve 0.7218gm KN03 in water and dilute to 1000m1 (1ml = 100mcg nitrate nitrogen). Preserve this with 2ml chloroform/L.
·         Standard nitrate solution: Dilute 100 ml stock solution to 1000 ml distilled water (1 ml= 10mcg nitrate nitrogen').
·        Take different aliquots of standard solution from 0.4, 0.8,………, 2.0 ml and one blank.
·        Take three different aliquots (0.4, 1.2, 2.0ml) of unknown sample.
·         Make up the final volume to 5ml with distilled water.
·        Take the O.D. of all the tubes at 220nm (if organic matter is present take the O.D. at 275 nm also)
·         Prepare a standard graph and plot the absorbance of unknown to find the concentration

Water Analysis : To Estimate The Amount Of Ammonical Nitrogen (NH3-N) of Given Sample By Finate Method

In waste water, the forms of nitrogen are of great interest in order of decrealing oxidation state. Nitrite, nitrate, ammonia & organic nitrogen all there forms of nitrogen as well as N2 are biochemically interconvertabale & are components of N2 cycle. they are of great interest for many reasons.
Ammonia is present naturally in surface & wastewater. Its conc. is generally low in ground water because it absorbs sail particles & clays & is not reached by from oils. It is produced largely by de amination of organic N2 containing compounds by hydrolysis of some water treatment plants Ammonia is added to react with chlorine to form combine fluorine residual ammonia conc. Encountered in water very strong less than 10 mg ammonia nitrogen per liter. In some natural surface & ground water to more than 30 mg per liter in some waste water.
Various methods available for the estimation of ammonia nitrogen are:
1.       Ammonia selective electrode method (0.03-1400mg NH3.N per lit.)
2.       Finite method (0.6mg NH3-N per lit.)
3.       Automated finite method (0.02-2mg NH3-N per lit.)
An intensely blue compound endophenol is formed by the reaction of ammonia, hypochloride & phenol catallized by sodiumpruside. This blue color can be mealuted at 640 nm.
1.  Phonal 10 in.(prepare weekly), Liquified Phonal (> 90 % )11.1 ml ethanol 95% (100ml),       sodium nitropruside (0.5%) (State in bottle up to 1 month)
2.  Alkaline citrate 10 In.
    - Trisodium citrate 20 gm.
    - Sodium hydroxide 1 gm
    (Make final vol. 100ml with D/W)
3.  Sodium hypochloride 10 In.
    About 5% available commercially
4. Oxidizing 10 In (prepare fresh)
  - Alkaline citrate 10 In. (100ml)
  - Sodium hypochloride (25ml)
5. Stock ammonia 10 in.
 - NH4CL   (0.0362 gm)
 -D/W (100ml)
  (1ml =1.22mg NH3 )
6. Std. ammonia 10 in.
  -Stock ammonia 50 In (1ml)
  -D/W (199ml)
7. Test tube- (12), Pipettes (1ml & 5ml ), colorimeter with cuvate
-  Take different aliquotes of NH4CL Std. 10 In from 0.1,0.2…..0.5ml.
-  In blank, do not add NH4CL make the final vol. 5ml with D/W. add 0.2ml phenol reagent   in all tubes.
-  add 0.2ml of sodium nitropruside 10 In. in all the 10 in
-  Stopper  the entire bottle with cap & incubate in dark at room temp. For 1 hr.
-  For unknown sample, take 3 aliquotes of 0.2,0.3,0.5ml & proceed in similar way above         ,mealute absorbance of all tubes at 640 nm
-  Prepare STD curve by platting absorbance of Std. against ammonia conc. Of STD.
-  Find out conc. Of unknown sample using STD curve.
1. The conc. of NH3-N in drinking water is …………………………….µgs/ml
2. The conc. of NH3-N in wastewater is …………………….µgs/ml