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)
(1ml =1.22mg NH3 )
6. Std. ammonia 10 in.
-Stock ammonia 50 In (1ml)
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