Explain how water reaches our homes?
Answers
Explanation:
Surface water is rain drained into rivers or creeks or collected in dams and water tanks. ... The treated water is pumped to reservoirs for storage. Reservoirs are usually on high ground so that water can flow into underground pipes or water mains. The water in the mains flows into the house when you turn on the tap.
Answer:
Explanation:
The process
“An experienced eye can easily tell the turbidity in water by just looking at it,” said a central laboratory officer at the Delhi Jal Board’s Haiderpur water treatment plant (WTP), who did not wish to be named. Turbidity is a measure of suspended particles in water — a higher turbidity makes water more cloudy.
“There have been times, around monsoon, when it reached as high as 6,000 and the water then looks red because a lot of mud gets mixed in it. But we can still bring it down to 1, as is the quality standard,” the officer said.
Delhi’s two main surface water sources are the Yamuna and Ganga which, officials said, account for around 90% of the water supply. The remaining is covered by ground water. Of the 10 treatment plants run by the DJB, the Sonia Vihar and Bhagirathi WTPs in East Delhi get raw water from the Ganga through pipelines stretching from Muradnagar in Uttar Pradesh, while eight others rely on the Yamuna and ground water supply. The process starts after raw water enters the treatment plant.
At Haiderpur, guards are on patrol near a Yamuna canal that supplies water to it to keep “miscreants” away. Inside, the water passes through four processes before it is released to the public. The first is pre-chlorination, which removes impurities at the start. In the next step, polyaluminium chloride and alum is mixed into the water to remove mud and dirt.
“Together they act as a coagulant, meaning they clump the suspended particles in the water so they can be removed in the clariflocculator,” the Haiderpur officer said. In a clariflocculator, which is a large round open tank, clumped particles settle at the bottom and are scraped away as sludge from an outlet below, while clear water is sent further and passed through sand and gravel filters.
An officer, who is part of the treatment operations team in the plant, keeps a register with a neatly drawn table of 13 columns for each parameter that is checked in the water on an hourly basis, before and after treatment, including turbidity, pH level and ammonia. A recent graduate assists the team in testing the water samples in a one-room laboratory.
The plant runs day and night, and staff keep changing every eight hours. The central lab in the plant, equipped with more advanced testing technologies, also checks raw and treated water quality against 30 parameters, with standards set by the BIS. “If any parameter is found to be higher than the standard, we have to make quick decisions. For instance, if ammonia is found to be high, then we either have to dilute raw water or shut production completely,” the officer said.
In the BIS report, all 11 water samples had failed in 19 parameters, including ammonia, turbidity and pH level. Paswan, who had released the report on November 16, had said in Parliament that water supplied by the DJB was not fit for drinking and had challenged Delhi Chief Minister Arvind Kejriwal for a retest. The CM, in turn, called the report false and politically motivated. At present, officials from both DJB and BIS have been appointed for a re-assessment.
Back at the Haiderpur plant, the “political situation” is mentioned occasionally and quickly shrugged off, but a certain pressure is apparent. “I can guarantee that the water which goes out to the public from here is safe for drinking,” the operations officer at the plant said, holding up clear water in his hand after it has passed through the sand and gravel filters.
The final treatment process is post-chlorination. “We add chlorine because… if there is any bacteria, virus or contaminant somewhere in the pipeline, the chlorine reacts with it and kills it after which its own presence is reduced,” said Ankit Srivastava, technical advisor to the DJB.
He said the presence of this “residual chlorine” is tested in about 500 water samples the DJB collects every day from its supply network across the city. If it is not found, then there’s a possibility of contamination somewhere in the pipeline. The samples are also tested against over 25 other parameters.