Quality parameter of Water

 Physical properties or Quality parameter of Water

• Suspended Solids
• Turbidity
• Color
• Taste and Odour
• Temperature

Suspended Solids

Suspended Solids

Physical quality of Drinking water

Turbidity

Turbidity

Physical quality of Drinking water

Colour

Colour

Physical quality of Drinking water

Taste and Odour

Taste and Odur - Physical quality of Drinking water

Chemical properties or Quality Parameter of Water

• Total Dissolved solids (TDS)
• Alkalinity
• pH
• Hardness
• Chloride Content
• Nitrogen content
• Phosphorus
• Fluorides
• Metals
• Dissolved Gases

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Pipe Appurtenances Valve and Joint in Water supply Piping

Pipe Appurtenances - Valve 

Check Valve: 

• These valves are used to check the flow of water in reverse direction. 
• These are generally provided on the delivery side of the pump. These valves work automatically.

Pressure reducing valve:  

• In hydraulics, a pressure reducing valve serves the same purpose as a "pressure regulator" valve in a compressed air system. 
• It is one of a variety of pressure control valves available for hydraulic circuits. It is always used in a branch circuit and never in the full pump flow line.

Air Relief Valve: 

• it is a type of safety valve used to control or limit the pressure in a system, pressure might otherwise build up and create a process upset, instrument or equipment failure, or fire. 
• The pressure is relieved by allowing the pressurised fluid to flow from an auxiliary passage out of the system.

Air Valve: 

• Provided at summits to release air pressure.

Relief Valve or Safety valve or cut-off Valve:

• Helps in regulating the water hammer pressure.

Scour valve: 

• This valve is used to drain the water out of the pipe system.

Sluice valve: 

• These valves are used to regulate the flow of water in the pipe system by dividing into number of sections.

Foot Valve: 

• Prevent entry of debris into the pumping system and prevent back flow.

Butterfly valve:

• Regulate and Stop the flow specially in large size conduits.

Globe Valve: 

• Direction of Flow changes by 90° twice

Surge arrestor: 

• Control of water hammer in pipe lines by absorbing surge energy.

Joint in Water Supply Piping:

Flexible joint: 

• Where Settlement of pipe line can occur.

Threaded joint:

• Recommended for connecting the GI pipes.

Simplex joint: 

• For joining asbestos cement pipes.

Flanged joint: 

• Recommended for temporary work where the pipe line is to be dismantled after work or to be shifted.

Expansion joint: 

• Provided at suitable intervals to take into account the change in pipe length due to temperature variations.

Collar joint: 

• Recommended for joining R.C.C pipes and asbestos cement pipes.

Spigot and socket joint: 

• Also known as Bell-spigot joint. Where spigot end is inserted into the bell end.

Joint in water supply Piping.jpg

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Self Purification of Stream - Environmental Engineering

Self Purification of Stream

A polluted stream undergoes self-purification

• Zone A – Zone of clear water
• Zone B – Zone of Degradation
• Zone C – Zone of Active decomposition
• Zone D – Zone of Recovery
• Zone E – Zone of recovery

Zone	Main Characteristics
Zone of Clear Water (1 & 5)	Clear water,  presence of fishes. 100% saturation
Zone of Degradation (2)	Dissolved oxygen level falls due to the decomposition of Organic Matter in this Zone. Dark and turbid water. Fishes may present Algae are absent. 40% saturation
Zone of Active Decomposition (3)	Zone of heavy pollution. Water is very dark and turbid Dissolved oxygen level falls to Zero. Critical Oxygen Deficient occurs. Formation of the dirty scum layer. Both fishes and algae absents 0% saturation
Zone of recovery (4)	Dissolved oxygen level increases and may reach to saturated value. Decomposition of organic matter takes place up to the Nitrate level. Both fishes and Algae reappear. BOD falls down. 40% saturation

Purification of sewage in river

When sewage or sewage effluents are discharged into the river, river gets polluted temporary, but the conditions do not remain so forever, because the natural forces  of purification such as dilution, sedimentation, oxidation, reduction in sunlight go on acting upon the pollutants  and bring back the water into its original condition. This process known as self purification and various forces responsible for this are described briefly below:

1. Dilution and Dispersion: 

• When sewage is discharged into large volume of river water, it gets rapidly dispersed and diluted. This results in reduction of concentration of organic matter in sewage.

2. Sedimentation: 

• The suspended solids in sewage gets settle down into the river bed by the action of gravity.

3. Oxidation: 

• The organic matter present in sewage gets oxidized by the microorganisms with the help of dissolved oxygen present in river and results in formation of stable products.

4. Reduction: 

• It occurs due to hydrolysis of organic matter settles down at the bottom of river bed either chemically or biologically.

The above natural forces of purification depend on various factors which are:

• 1. Temperature

• 2. Turbulence

• 3. Velocity of river stream

• 4. Availability of dissolved oxygen

• 5. Type and amount of organic matter present

• 6. Rate of re-aeration.

classification of secondary treatment units:

Important Terms

Hydrolysis:

• It is a chemical process in which a molecule is cleaved into two parts by the addition of a molecule of water. One fragment of the parent molecule gains a hydrogen ion (H+) from the additional water molecule. The other group collects the remaining hydroxyl group (OH-).

Pyrolysis

•  It is the process in which the most of organic matter upon heating in an oxygen free atmosphere splits through a combination of thermal cracking and condensation reactions into gaseous, liquid and solid fractions.
• The process typically occurs at temperatures above 430 °C (800 °F) and under pressure. It simultaneously involves the change of physical phase and chemical composition and is an irreversible process. So it is an endothermic process.

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Disposal of refuse - Environmental Engineering

Disposal of refuse and Sewage sickness of Land

Method of disposal of refuse

Landfill or Burying:

• Landfill refers to the disposal of waste material by burying it.
• It is an extended storage area for non-biodegradable waste.
• Landfill is an area, which prevent contamination from the waste entering the area surrounding by soil and water and it also helps to reduce odor and pests

Incineration: 

• This method involves burning of solid wastes in a furnace until the wastes are turned into ashes
• In this process, the combustible portion of the waste is combined with oxygen forming carbon dioxide and water, which are released into the atmosphere
• Incinerators are made in such a way that they do not give off extreme amounts of heat when burning solid wastes
• Suitable temperature and operating conditions are required to achieve for incineration
• It reduces the volume of waste up to 20 or 30% of the original volume
• This method of solid waste management can be done by individuals, municipalities and even institutions

• It involves of two stages involved such as drying and combustion. Drying and combustion may be accomplished either in separate units or successively in same units depending upon the temperature constraints or control parameter. It is an exothermic process.

Fluidized bed incineration:

• It is a combustion technology used to burn solid fuels. 
• In its most basic form, fuel particles are suspended in a hot, bubbling fluidity bed of ash and other particulate materials (sand, limestone etc.) through which jets of air are blown to provide the oxygen required for combustion or gasification. 
• The resultant fast and intimate mixing of gas and solids promotes rapid heat transfer and chemical reactions within the bed

Pulverization 

• It refers to the action of crushing and grinding heavier solids into the lighter solids.

Composting 

• It is a natural biological process, carried out under controlled aerobic conditions (requires oxygen).
• In this process, various microorganisms, including bacteria and fungi, break down organic matter into simpler substances.
• The effectiveness of the composting process is dependent upon the environmental conditions present within the composting system i.e. oxygen, temperature, moisture, material disturbance, organic matter and the size and activity of microbial populations.

process of composting

Bangalore method

• It is an anaerobic method conventionally carried out in pits. 
• In the Bangalore method of composting, dry waste material of 25 cm thick is spread in a pit and a thick suspension of cow dung in water is sprinkled over for moistening.

Indore method

• It is an aerobic method. 
• The Indore method of composting in pits involves filling of alternate layers of similar thickness as in the Bangalore method.
• However, to ensure aerobic condition the material is turned at specific intervals for which a 60 cm wide strip on the longitudinal side of the pit is kept vacant.

There are mainly two methods (Indore and Bangalore method) adopted in India for the decomposition of Solid wastes generated. 

The main difference between Indore Method and Bangalore Method for decomposition of MSW is given below:

Indore Method	Bangalore Method
Decomposition of MSW by composting is done aerobically.	Decomposition of MSW by composting is done an-aerobically.
Decomposition takes 2 - 3 Months	Decomposition takes 5 - 6 Months
Mixing is ensured either Mechanically or manually	No mixing is done.

• In Composting with a combination of proper environmental conditions and adequate time, microorganisms turn raw putrescible organic matter into a stabilized product.

• Through composting, readily available nutrient and energy sources are transformed into carbon dioxide, water, and a complex form of organic matter compost. 

• Process management can be optimized for a number of criteria, including the rate of decomposition (to reduce residence time in reactors and thus minimize facility size requirements), pathogen control, and odour management.

• The key parameters are the available carbon to nitrogen (C: N) ratio, moisture, oxygen, and temperature.

• Decomposition slows dramatically in mixtures under 40 to 45 percent moisture, which can lead facility operators to prematurely assume compost is stabilized and ready to sell.

• A minimum moisture content of 50 to 55 percent is usually recommended for high rate composting of MSW.

• During the active composting phase, additional water usually needs to be added to prevent premature drying and incomplete stabilization. MSW compost mixtures usually start at about 52 percent moisture and dry to about 37 percent moisture prior to final screening and marketing.

C/N ratio is an important factor in composting

• since bacteria use nitrogen for their cell structure building and carbon for food.
•  The optimum composting C/N ratio should be in range (30 - 50)
•  So, If C/N ratio is more, Nitrogen is utilized prior to that of carbon, which results in incomplete digestion of organic matter.

gases produced from a land fill site

• Sanitary landfill involves dumping the waste in layers and compacting them after each layer, hence tractor can be used very effectively for this purpose.It is simple and economical.

• But there is continuous evolution of foul gases which may be explosive in nature. The major constituent gases produced from a land fill site are carbon dioxide and methane.

• It also causes leachate in landfills which pollutes the nearby ground water thereby impacting the ecology of the area.

Sewage sickness of  Land: 

• When sewage is applied continuously on a piece of land, the soil pores or voids may get filled up and clogged with sewage matter retained in them. This phenomenon of soil getting clogged is known as sewage sickness of the land.

The following preventive measures may be adopted to avoid sewage sickness:

Pre-treatment of sewage	Sewage should be given some pre-treatment before it is applied on land.
Rotation of crops	It is desirable to grow different types of crops on a piece of land instead of one single crop. Rotation of crops minimizes the chances of sewage sickness.
Drainage of soil	Subsoil drain pipes should be laid in sufficient number to collect the percolated effluent.
Depth of sewage	The depth of sewage on land should be carefully decided by keeping in view the climatic conditions, drainage facilities, nature of crops, and characteristics of the soil.
Alternative arrangement	There should be ample provision of extra land so that land with sewage sickness can be given the desired rest.
Intermittent application	Sewage should be applied on land at intervals. The period between successive applications depends on the general working of sewage farms and the permeability of the soil. Depending on the nature of the soil, this period between successive applications varies from few hours to few weeks.
Treatment to land	The land affected by sewage sickness should be properly treated before it is put up in use again. Clogged surfaces should be broken by suitable equipment.

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Environmental Engineering

for Civil Engineers

Water Supply and Sewage Treatment.

Water Supply Sewage Treatment water Distribution Definitions

Latest Article

Types Treatment unit and its Mechanism

for example - trickling filter, Oxidation pond, Septic tank and its nature like aerobic or anaerobic process More

Disposal of refuse.

Method of disposal of refuse, process of composting, C/N ratio in composting Read More

Self Purification of Stream

A polluted stream undergoes self-purification, Purification of sewage in river Read More .

Sewage Sickness of Land

When sewage is applied continuously on a piece of land, the soil pores or voids may get filled up and clogged with sewage matter retained in them. This phenomenon of soil getting clogged is known as sewage sickness of the land. Read More

Important Content

The density in kg/cum (in situ) of municipal solid waste

The density of municipal solid waste for a typical Indian city is 400 kg/cum to 600 kg/cum with a calorific value of 5000 to 6000 kJ/kg.

The density of municipal solid waste for a typical city of the USA is 100 kg/cum to 600 kg/cum with a calorific value of 15000 kJ/kg approximately.

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Popular in Civil Engineering

Important Theories.

Types of Footing and Settlement

Types of shear failure:

IS code specification for permissible settlement of Foundation

more

Solid Waste

Important for Exams

• Pyrolysis
• Hydrolysis
• Purification of sewage in river
• Tunnels

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