Wastewater Story

Water coming out of a laundry is waste water as it contains harmful substances that are mixed with it and should be treated so as to consume it.

Sewage is defined as waste water due to which it is a liquid waste.

During the process of waste water treatment first the sludge is obtained and then at the end the biogas is obtained. Thus, both are products of wastewater treatment.

Open drains are very dangerous and harmful as it is a breeding place for all the disease-causing organisms, flies, mosquitoes etc.

Asthma is not a water-borne disease but it is an air-borne disease.

Chlorine is a very good oxidizer. It kill pathogens and germs by breaking their bonds. This is how it disinfects water.

Sewerage is the drainage that carries the sewage.

Phosphates are the inorganic impurities of sewage. These are removed by using bacteria.

The sand, fine gravel and the medium gravels are used to filter as they form a layer so that efficient filtration takes place.

Sewer contains the waste water as it is an underground carriage system for the sewage. But it doesn’t produce any additional sewage. Thus, it is not a source of wastewater.

Open drains are a concern as it is the breeding ground for mosquitoes and many other germs. It pollutes our environment with a foul smell and spread diseases.

(a)False.

Sewage is a liquid waste which causes water pollution and soil pollution.

(b) True.

Since the used water cannot be used further without treating it thus, it is waste water.

(c) True.

After the processing of wastewater in a wastewater treatment plant. It can be reused.

(d) False.

Where underground sewerage systems and refuse disposal systems are not available, the low-cost on-site sanitation system can be adopted.

Open drains are harmful for human health as :

i) It is the breeding ground for flies, mosquitoes and many other disease-causing germs.

ii) It creates air pollution by its foul smell.

iii) During the rainy season these drains overflow and pollute the surroundings especially the water bodies and causes many water-borne diseases like diarrhoea, cholera etc.

Two inorganic impurities present in sewage are nitrates and phosphates.

Organic impurities present in sewage are pesticides, herbicides human faeces etc.

two alternative arrangements for sewage disposal where there is no sewerage system are :

i) Low cost onsite sewage disposal system like a septic tank.

ii) Hygienic on-site human waste sewage disposal technology is also good as these toilets do not require scavenging. Excreta from toilet seats directly flow to a nearby biogas plant through cover drains.

This is not a proper waste disposal method. We should throw the empty packets into proper dustbins. Generally, these empty food packets are made up of polythene which is non-biodegradable substances and thus pollutes the environments. If we throw it in a proper dustbin then it can be disposed of properly.

(a) We should not throw used tea leaves into sink as it chokes the drain and do not allow free flow of oxygen which hampers the degradation process.

(b) We should not throw cooking oil and fats down the drain as they harden after some time and block the drain pipe. In an open drain, this oil and fats clog the pores of the soil and reduce the effectiveness of soil in filtering water.

a) Inorganic impurities – ii) nitrates and phosphates

b) Organic impurities - iv) pesticides and herbicides

c) Nutrients - i) phosphorus and nitrogen

d) Bacteria – iii) Cholera and Typhoid.

Processes involved in a wastewater treatment plant :

1. Large objects like plastic bags are removed by passing wastewater through bar screens.

2. Wastewater enters a grit and sand removal tank.

3. Sand, grit and pebbles are made to settle by decreasing the speed of incoming wastewater.

4. Water is made to settle in a large tank with a slope in the middle.

5. Sludge is scraped out and skimmer removes the floating grease.

a) sludge: The settled solids that are removed in wastewater treatment with a scraper.

b) sewage: Wastewater released from homes, industries, hospitals and other public buildings.

c) wastewater: Water from the kitchen used for washing dishes.

(X) : waste water or sewage

(a) : Phosphorus and Nitrogen

(b) : Bacteria like cholera (vibrio coma), typhoid (salmonella typhosa) and microbes which cause dysentery.

Different types of inorganic and organic impurities generally present in sewage are as follows:

Inorganic impurities: nitrate, phosphate, metals etc.

Organic impurities : human faeces, animal waste, oil, urea present in urine, pesticides, herbicides, fruits and vegetable peels etc.

Wastewater released by home, industry, hospital etc. are called sewage. The small and big pipes that takes away sewage is called sewers. The network of this big and small pipes (sewers) is called sewerage. Just like transport system this sewerage carries sewage from the point of being produced to the point of disposal through these sewers.

A very large number of our people defecate in the open. It may cause water pollution and soil pollution. Both the surface water and ground water get polluted. ground water is the source for wells, tube wells and handpumps. Thus, it becomes the most common route for water borne diseases like cholera _________, dysentery, etc.

Various steps of cleaning Wastewater in a waste water treatment plant are as follows: 1. Wastewater is passed through bar screen to remove large objects like rags, sticks, cans, plastic packets etc.

2. This water is then passed through grit and sand removal tank to allow sand, grit and pebble to settle down by reducing the speed of the incoming water.

3. The water is then allowed to settle in a large tank which is sloped towards the middle. Solids like faeces settle at the bottom and are removed with a scraper. This is the sludge which is then transferred to a bio-gas plant for bio-gas production. Here the floatable solids like oil and grease is removed from water by a skimmer. Water so cleared is called clarified water.

4. Then air is pumped into this clarified water to help aerobic bacteria to grow which consume human waste, soap and other unwanted matter still remaining in water. The water is kept undisturbed for several hours so that the suspended microbes settle down at the bottom of the tank as activated sludge and the water is then removed from the top.

5. The treated water is then discharged into a sea or river or into the ground. Sometimes the water is disinfected by chlorine before releasing it into the distribution system.

To minimize waste and pollutants at their source the following measures can be taken:

1. We should avoid use of plastic bags by using bags made up of jute or cotton.

2. Tea leaves, peels of fruits and vegetables etc. can be used to make compost for kitchen garden.

3. Old Polythene or plastic jars and bottles can be reused by making vase, pots, pen stand etc,

4. Proper sanitation system should be there in our houses so that people will not defecate outside and thus pollution can be reduced.

5. With waste paper we can make paper mache and use it for decorative purposes.

6. By following 3R i.e. reduce, recycle and reuse we can minimize our waste produced and thus control pollution.