1. Introduction

The District of AMBANJA is among the five districts which form the Region of DIANA; it is in the South of Diego Suarez, the population its account 200 245 it is distributed in Ten (10) Fonkotany. The following table gives the numbers of populations that the RIVIERE uses as drinking water.

Table 1. Numbers of populations use the river as drinking water

The characteristics of this river is given by the following table:

Table 2. Characteristics of the SAMBIRANO River

This study has four parts, the first part is the bibliographic synthesis, the second part is the measurement results for the physicochemical parameters and the microbiological analysis, the third part the interpretation of the results, and the fourth part is the method for disinfection, we will end with the conclusion.

2. Bibliographic Synthesis

Three possible structures for water, solid, liquid or gaseous. The chemical separation of water is the dissociation into H+ and an OH-.

Water contains several organic materials; it has dissolved form in water. Metals can exist in water, it presents in the form of a trace.

Pollution that exists in the water, too high concentrations of pollution in the water causes a microbe.

3. Quality Standard

For drinking water reference is made by the standard trios: WHO, European Union (U E) and the Malagasy State (E.M).

1 - Recommendation of the WHO

2 - Recommendation of EU

3 - Recommendation of the EM

Table 3. Recommendation of the WHO

Table 4. Recommendation of the EU

Table 5. Recommendation of the EM

4. Parameters of Analysis

The pH to know the water is basic, or acid and neutral, the turbidity to know the transparency of the water, the conductivity to know the quality of the salt dissolved in the water, the organic matter makes it possible to estimate the quantity of organic matter in water such as BOD, BOD5 and COD.

The T A and TAC is the basic salt content, that is, the determination of the OH- ion concentration in the water.

Nitrate assays is the determination of the concentration of nitrates in water, determining the concentration of calcium and magnesium for the existence of total hardness, the concentration of iron that exists in water is known by the dosage of total iron, the concentration of ammonium in water indicates the existence of pollution.

The average concentration of calcium, sodium and magnesium play a very important role for the daily life of humans.

Microbiological analysis these very important for drinking water.

Results of Measures

I – Physical parameters

1. Temperature

Table 6. Represents of the temperature

Figure 1. Temperature measurement

2. Turbidity

Table 7. Represents of the turbidity

Figure 2. Turbidity measurement

3 – pH

Table 8. Represents of pH

Figure 3. pH measurement

4 - Conductivity

Table 9. Represents of conductivity

Figure 4. Conductivity measurement

II – CHEMICAL PARAMETERS

1 – Mineralization

Table 10. Represents of mineralization

Figure 5. Mineralization measurement

2 – Total hardness

Table 11. Represents of Total hardness

Figure 6. Total hardness measurement

3 - Calcium hardness

Table 12. Represents of Calcium hardness

Figure 7. Calcium hardness measurement

4 - Complete alcalimetric title (T A C)

Table 13. Represents of complete alcalimetric title

Figure 8. TAC measurement

5 – Calcium

Table 14. Represents of calcium

Figure 9. Calcium measurement

6 – Magnesium

Table 15. Represents of magnesium

Figure 10. Magnesium measurement

7 – Sodium

Table 16. Represents of Sodium

Figure 11. Sodium measurement

8 - Organic material

Table 17. Represents of Organic material

Figure 12. Organic material measurement

9 – Ammonium

Table 18. Represents of ammonium

Figure 13. Ammonium measurement

10 – Iron total

Table 19. Represents of Iron total

Figure 14. Iron total measurement

11 – Chlorides

Table 20. Represents of Chlorides

Figure 15. Chlorides measurement

12- Nitrates

Table 21. Represents of Nitrates

Figure 16. Nitrates measurement

13 – Copper

Table 22. Represents of Copper

Figure 17. Copper measurement

III – MICROBIOLOGICAL ANALYSIS

Table 23. Measurement results of the microbiological

Figure 18. Microbiological analysis results

The table shows that the water of the river is microbial, so it must be disinfected. [14], [15].

For the disinfected one uses the method by chlorination.

5. Method of Treatments

We performed a chlorine demand test of this sample; this test provides an optimal rate of calcium hypochlorite [Ca(Cl)₂] required to have disinfection.

The result of the chlorine demand is given by the following table N° 24

Figure 19. The result of the chlorine demand is given by the following

Interpretation of the curve:

from 1 to 1.75 mg / L: chlorine in the form of amine compounds

from 1.75 to 2 mg / L: destruction of chloramines by an increased dose of chlorine.

from 2 to 3mg / L: progressive increase of Cl₂

the optimal dose of calcium hypochlorite used is between 2 to 3 mg / L to avoid any risk of contamination, during the rainy season.

Table 25. Post-treatment results for microbiological analysis

Figure 20. Microbiological analysis results after treatment

6. Interpretation of Results

- Physical parameters

The temperature found is 19.3°C, below 25°C, it is eligible for international standards for drinking water, the turbidity is 11.7 NTU, greater than 5 NTU so outside the value required for the standard of potability, the pH is 7.58 it between 6.5 and 8.5 admissible to the potability standard and the conductivity is 73.8μS / cm between 180 and 1000 μS / cm meets the standard required for standards international. The physical parameters therefore perfectly meets the potability norm, in particular the turbidity is excluded for the required values the river water SAMBIRANO is very hard.

- Chemical parameters

The river water of SAMBIRANO is mineralized because the concentration found is equal to 68mg / L, it is very close to the value required for international standards.

The total hardness is 9.7 °f and the hardness Calcique is 4.5 °f so the calcium and magnesium level in the SAMBIRANO River water is acceptable for the potability standard.

Organic matter is 1.6mg / L, ammonium is 0.14mg / L they are acceptable for international standards.

The calcium is 18mg / L, the magnesium is 12.64mg / L, they are eligible for the standards required for drinking water because the calcium is 400mg / L the magnesium is 50mg / L.

The sodium is 2,3mg / L the required value is 200mg / L it qualifies unwillingly the insufficiency of this found sodium concentration.

The T A C is 3.2 °f the required standard is 11 °f so it is acceptable for drinking water.

The Nitrate is 7.39mg / L the required value is 44mg / L on average, therefore eligible for the standard of drinking water. The concentration of chloride found is 3.55mg / L, it is far below the value required for the standard of drinking water because the required standard is 250mg / L.

Chemical parameters almost acceptable to international standards, notwithstanding some insufficiency of the concentration found as calcium, chloride, magnesium and sodium.

- Microbiological analysis

For the microbiological analysis of the water of the SAMBIRANO River, the results found are excluded to international standards for drinking water, so the water is microbial.

I propose you a method for the disinfection of this water is by the method of CHLORATION with the optimal value and without risks meme for the period of rain one uses between 2 and 3,5mg / L of calcium hypochlorite.

7. Conclusions

In conclusion the results of measurement for the physical parameters of the river SAMBIRANO: the pH = 7,58, temperature = 19,3°C and the conductivity is 73μS / cm are standard for drinking water, but the value of the turbidity found is very large, ie equal to 11.7NTU, this value is excluded for the standard required for drinking water because limit value is less than 5NTU. So the SAMBIRANO river water can use but it is necessary to treat the turbidity before using because the water is very hard.

For the chemical parameters are in norms but their found concentrations are very low, respectively the concentrations of chloride 3,55mg / L the required value is 250mg / L, sodium 2,3mg / L the required value is 200mg / L, magnesium 12, 64mg / l the required value is 50mg / Let the Calcium 18mg / L the found value is 400mg / L. The water is drinkable despite some concentrations of very important parameters for drinking water is insufficient so it is necessary to increase their concentration before being used, I propose the method of demineralization that is to say the increase in the rate of insufficient parameters for the river water of SAMBIRANO.

For microbiological parameters the microbiological parameters that we will study in the SAMBIRANO river does not answer exactly the norms required for the international norms for the drinking water that is to say the water is microbial, that is why my work is used the method by chlorination to disinfect these microbes.