ANDHRAPRADESH REVISED STANDARD DATA FOR ENGINEERS 2020-21

GOVERNMENT OF ANDHRAPRADESH REVISED STANDARD DATA

With Schedule of rates 2020-21

CHEMICAL WATER QUALITY PARAMETERS

          The chemical water quality parameters mainly deal with the dissolved solids and impurities in the water. The parameters are listed below:

1) PH

2) Alkalinity

3) Hardness

4) Dissolved solids

1) P^H:-

          PH is the potential extended by H+ ions in water. The value of PH determines the logarithm of reciprocal of H+ ion concentration present in water. It is an indicator of acidity (or) Alkalinity of water.

Similarly POH is the potential exerted by OH- ions present in the water. 

                           P^H = log₁₀ [1/H⁺] mol/l

                           P^H = - log₁₀ [H⁺] mol/l

                           P^OH  = - log₁₀ [OH^-] mol/l

Classification of water based on PH:

a) Neutral water

                          [H⁺] = [OH^-] = 10^-7 mol/l

                                        P^H = 7

                                        P^OH  = 7

b) Acidic water

                          [H⁺] > 10^-7 mol/l            P^H < 7

                          [OH^-] < 10^-7 mol/l           P^oH  > 7

c) Alkaline water

                            [H⁺] < 10^-7 mol/l             P^H > 7

                            [OH^-] >10^-7 mol/l         P^oH  < 7

Measurement of P^H:

          PH is exactly measured with Potentiometer and can approxly measured with help of Indicators.

          An indicator is the substance which is either a weak acid or weak base which shows characteristic change in its color at a certain P^H range.

          Indicators are used to find-out the end points of Titration. The indicators which change their color in acidic range are called as "Acidic Indicators" and those which change their color in basic range are called "Basic Indicators".

Example: Methyl orange is an acidic indicator (P^H = 4.5) and Phenolphalein is an Alkaline Indicator. 

P^H of drinking water is 6.5 to 8.5 

Rejection is : Les than 6.5, and more than 9.5.

2)Alkalinity:-

          The ability to neutralize ions present in water is called "Alkalinity". In natural water the following ions are responsible for major of the alkalinity and are called "Major Alkaline Species".

        1) 0H ^-          2) co₃^2-         3) HCO₃ ^–

Following ions constitute a very small fraction of alkalinity and are referred as "Minor Alkaline Species".

1) HS ^-       2) NH₃       3) HPO₄^-      4) H₂PO₄ ^-     5) H₃SIO^{3 -}      6) H₂BO^{3 –}

Note:-

          The above 9 species (3-major and 6-minor) only can have ability to alkalinity such that they are called as Alkaline species.

IMPACTS OF ALKALINITY:-

1) Alkalinity imparts bitter taste to water.

2) Alkalinity forms precipitate of CaCO3 and Mg(OH)2 which causes deposition (or) Incrustation over pipes and other water treatment units.

3) HARDNESS:-

          Hardness in water is the characteristic which prevents the formation of sufficient lather (or) foam with soap. It is caused due to multivalent metallic cations in water.

Ex:- Ca²⁺, Mg²⁺ , fe²⁺ etc.,

Note:-

          Na⁺ also present in the water but it doesn't contribute hardness to water.

Types of Hardness:-

1) Carbonate hardness:-

          Hardness due to Carbonates and Bicarbonates associated with multivalent metallic cations is referred as Carbonate Hardness. It is also called as Temporary Hardness as it can be easily removed by adding Lime.

2) Non carbonate Hardness :- 

Hardness due to chlorides, Sulphates, Nitrates etc., associated with multivalent metallic cations is referred as Non Carbonate Hardness. It is also called as Permanent hardness as it can't be removed simply by boiling water or by adding lime. In order to remove permanent hardness following softening techniques are adopted.

a) Lime soda method

b) Zeolote/ Ion exchange method

c) Demineralization method 

Impacts of Hardness in water :-

· Lesser foam formation there by increasing soap consumption

· If hardness is not present in water, it reduces the taste of food

· A certain amount of hardness is required for proper functioning of the body

· The hardness providing compounds such as Mgso₄, Caso₄ etc. produce laxative effect if present in excess.

Limits of Hardness:-

1) acceptable limit= 200 mg/l   as Caco₃

2) cause for rejection=600 mg/l    as Caco₃

3) Preferred limit=(75 to 115 mg/l   as Caco₃)

4) Dissolved Solids:-

          This dissolved solids are measured either by Gravimetric method (or) Specific conductivity test.

          The gravimetric method will give exact result where as the specific conductivity test will gives approximate method. In specific conductivity test, TDS is measured by determining electrical conductivity of water using Di Ionic water tester. 

Limitation:- This test gives approx amount of TDS as the compounds which dissolved in water but do not get ionized can't be measured in this test like phenolic compounds, alkaholic compounds etc.,

PHYSICAL QUALITY PARAMETERS OF DRINKING WATER

The drinking water should have the following physical properties:

1) Suspended solids

2) Turbidity

3) Color

4) Taste & Odor

5) Temperature

1) Suspended solids :-

In the drinking water the suspended solids should not be present even in small amounts.

For drinking water the suspended solids must be zero.

Acceptable limit of suspended solids: Zero.

2) Turbidity :-

The word turbidity indicates that the property of obstructing the light through it. The turbidity of water can be determined by Jackson's Turbidimeter, Baylis Turbidimeter, Nephelometer.

Acceptable limit of suspended solids:- 1 JTU (Jackson Turbidity Units)

Rejectable limit :- 5 NTU (Nephleometer Turbidity Units).

3) Color :-

The drinking water should be color less because the color indicates that impurities present in the water. 

Acceptable limit of color :- Colorless

4) Taste & Odor :-

The taste of the drinking water should be comfortable to consume and it should not impart bitter taste.

The odor of the water should not impart bad smell. The units to measure odor is Threshold odor number.

5) Temperature :-

The drinking water is acceptable when it contains 10o C to  25o C

If temperature of water < 10o C -- difficult to consume

If temperature of water > 25o C -- biological reaction

Special Thanks to CHINTHA TEJA

STREET LIGHTING

Objectives of street lighting:

The objectives of street lighting are

1) Ensure that fast traffic moves safely,
2) Facilitates pedestrian movements,
3) Ensure that pedestrians and vehicle drivers recognize obstacles; and enhance security,
4) The first is only important for through routes. In residential areas, where traffic moves slowly, it will not be an important concern.

Definitions and description:

The lamp is the source of light, which converts electrical energy into radiation. The main types of lamps in use are:

1) Tungsten lamps (designated GLS): in which a small wire contained in a glass bulb is heated to a high temperature in a vacuum.

2) Fluorescent lamps (designated MCF and TL): in which ultra-violet radiation causes phosphor powder to glow inside a tube.

3) Discharge lamps: in which an electric current is passed through a mixture of gasses in a sealed tube. Examples are low-pressure sodium, high pressure sodium and high pressure mercury (designates SOX, SON and MBF or HPL-N respectively).

The lantern refers to the complete street lighting fixture, including the lamp and the pole or other means of raising it above the street

The luminous flux represents the quantity of radiation emitted by a lamp, measured in units of lumens.

The intensity of light by a lamp is measured in units of candelas.

The Luminance of a point on the road surface that is receiving light from a lantern equals the intensity of the light emitted by the lamp divided by the square of the distance of the point from the lamp.

It relates to the incident light falling on a surface and so is higher close to the lamp. It is measured in terms of lux (Lumens per square metre).

Another measure of the intensity of light is Luminance, which is a measure of the light reflected from the road surface. It is measured in candelas per square metre.

It is commonly used to assess lighting requirements for heavily trafficked roads and has limited relevance to the needs of low-income areas.

ANGANWADI BUILDING PLANS IN ANDHRAPRASEDHA

 

Credits: Architech Engineers, hyderabad