Category: water

Role and Quality of Mixing Water in Concrete

Role of Water in Concrete

Water is the most important & least expensive ingredient of concrete. It plays an important role in mixing, laying, compaction, setting & hardening of concrete.

The strength of concrete depends on the quality & quantity of water used in the mix. The functions of water in the concrete mix are given below:

Role and Quality of Mixing Water in Concrete

1. It acts as a lubricant for the fine and coarse aggregate & makes the mixture workable.

2. It acts chemically with cement to form the binding paste.

3. It is employed to damp the aggregate surface in order to prevent it from absorbing water vitally necessary for chemical action.

4. It facilitates the spreading of aggregate.

5. It helps to flux the cementing material over the surface of the aggregate.

6. It enables the concrete mix to flow into moulds.

Quality Of Mixing Water In Concrete

The water to be used for preparing the concrete should fulfil the following requirements.

1. It should be fresh & clean.

2. It should be free from organic impurities injurious amounts of acids or alkalies, hygroscopic, greasy & oily substances.

3. It should be free from iron, vegetable matter, or any other substance which is likely to have an adverse effect on concrete or reinforcement.

4. It should be fit for drinking purposes.

5. The PH value shall generally be between 6 and 8.

Read More:

Role of Water in Compaction of Soil

Types of Concrete

Factors Affecting The Quantity Of Sanitary Sewage

Factors affecting the quantity of sanitary sewage

The quantity of sanitary sewage or D.W F is mainly affected by the following factors:

1) Rate of water supply

The quantity of sanitary sewage varies with the rate of water supply. The rate of water supply is not constant, but it fluctuates. These fluctuations may be seasonal, daily and hourly The rate of sewage is assumed as equal to the rate of water supply.

2) Population

The quantity of sanitary sewage directly depends on the population. As the population increases the quantity of sanitary sewage also increases and vice versa.

3) Type of area served

The quantity of sanitary sewage also depends on the type of area such as residential, industrial, or commercial.

4) Infiltration and exfiltration

The percolation of subsoil water in the sewer through the defective joints or cracks of the sewer is called infiltration.

The leakage of sewage from the sewer into the ground surrounding the sewer is called ex-filtration. Infiltration increases the quantity of sewage. On the other hand, ex-filtration decreases the quantity of sewage.

What is Sanitary & Storm Sewage, Dry And Wet Weather Flow

Determination of Quantity of Sanitary Sewage

What is Sanitary and Storm Sewage, Dry And Wet Weather Flow

Sanitary Sewage

Sanitary sewage includes liquid wastes of domestic and industrial places.

Storm Sewage

Storm sewage includes surface runoff developed during and immediately after the rainfall over the concerned area.

Dry Weather Flow(D.W.F)

The sanitary sewage which flows in dry season is known as dry weather flow.
It consists of two types of sewage:
a) Domestic sewage.
b) Industrial sewage.

The quantity of D.W.F depends upon the factors:
a) Infiltration & ex-filtration.
b) Nature of industries.
c) Population.
d) Rate of water supply.

Wet Weather Flow(W.W.F)

The combined flow of sanitary sewage and stormwater in the rainy season is known as wet weather flow.

Variation In Flow Of Sewage

The flow of sewage is directly related to the flow of water supply. As the water supply varies from hour to hour, day to day, month to month, and season to season. The flow of sewage also varies accordingly. The peak flow should be ascertained by different observations.

Determination of Quantity of Sanitary Sewage

Factors Affecting The Quantity Of Storm Sewage

What is Infiltration – Infiltration Rate and Capacity

WHAT IS INFILTRATION

When water falls on a given formation, a small part of it is, first of all, absorbed by the top thin layer of soil, so as to replenish the soil moisture deficiency. Thereafter, any excess water moves downward where it is trapped in the voids and becomes groundwater. This process, whereby, water enters the surface strata of the soil and moves downward, towards the water table, is called infiltration.

INFILTRATION RATE

The actual prevailing rate at which water enters the given soil at any given time is called the infiltration rate.

INFILTRATION CAPACITY

The maximum rate at which soil in any given condition is capable of absorbing water is called its infiltration capacity.

11 Factors Affecting The Rate of Water Demand

Following 11 factors affecting the rate of water demand:

Size of city
Climatic condition
Due to Habits
Industrial and commercial activity
Quality of water supply
The pressure in distribution systems
Development of sewage facility
System of supply
Cost of water
Policy of metering
Living Standards

1. Size of city

Large cities mean they have large populations with lots of amenities. So, large cities require more water as compared to small cities.

2. Climatic condition

People living in hot climates need more water than those living in cold climates. This is because a hot climate makes people thirsty more than a cold climate. Not only this reason but also require more water for gardening, street plant watering, park. Also, the duration and frequency of human bathing is greater than in cold weather.

3. Due to Habits

Some bad habits can increase the rate of water demand like – Leaving water taps open, not fixing leakage of water, washing things repeatedly for no reason, watering plants unnecessarily, etc. But, opposite habits of the above points can decrease the rate of water demand.

4. Industrial and commercial activity

The presence of industry in an area means that the demand for water will be high. In industry, they need water to cool their engines, wash their products, and so on.

5. Quality of water supply

If the quality of water is good, the demand for water will be high as compared to low-quality water.

6. The pressure in distribution systems

The high pressure in distribution systems increases the rate of water demand. On the other hand, low pressure in distribution systems decreases the rate of water demand.

7. Development of sewage facility

The presence of sewage or sanitary systems increases the rate of water demands and vice-versa. In this case, more water is required to use Bathtub, Shower, Bidet, etc.

8. System of supply

If water comes to the consumers for 24 hours, then the use of water will increase, hence, the rate of water demand will be high. On the other hand, if water is served only for a fixed time, it may be once or twice a day, then the use of water will reduce, hence, the rate of water demand will be low.

9. Cost of water

Water price is also an important factor that affects the rate of water demand. If the cost is increased, the water demand will decrease and vice versa. If the price of water is high, the wastage of water will be less because consumers will try to reduce unwanted usage of water so that they have to pay less money.

10. Policy of metering

The policy of metering also affects the rate of water demand. Installing meters in consumer houses decreases the rate of water demand, On the other hand, if there is no meter, the demand for water increases. But, sometimes, some policies are imposed on the consumers, like – the price of per liter water will be the same for all consumers for a certain limit(take an example: 20 liters per day per head), but after crossing their daily limit (if the consumer uses more than 20 liters), the price of per litter water will be more. This type of policy helps to decrease the rate of water demand.

11. Living Standards

The rate of water demand also depends on the consumer’s economic status. Rich consumers use more water as they do not think about the cost of the water. Rich families also use more home appliances( like – Washing Machine, Sprayer, Dishwasher, Car Washer, etc.) that may require more water. Meanwhile, middle-class and poor consumers use less water as they use fewer appliances and cost is another factor for them.

Water Quantity Estimation for a City

Let’s assume a city ‘A’, the population of this city is 200k. Before designing the water supply scheme, we need to calculate the estimated water consumption.

Here, two things are needed: one is per capita demand in liters per day per head. Another is the population of the location where water is to be served.

Quantity of water = Per capita demand * population

Ring Water Distribution System

Grid Iron System