Muncipal water treatment , Biology

Assignment Help:

The modern water treatment plan is often called upon to perform wonders with the water fed to it.  The clear, safe , even tasteful water that comes from a faucet may have started as a murky liquid pumped from a polluted river laden with mud and swarming  with bacteria. Or, its source may have been well water, much   too hard for domestic use and containing high levels of stain-producing dissolved iron and manganese. The water treatment plant operator's job is to make sure that the water plant product presents no hazards to the consumer.

A schematic diagram of a typical municipal water treatment plants is shown in fig. 2.1. This particular facility treats water containing excessive hardness and a high level of iron. The raw water taken from wells first goes to an aerator. Contact of water with air removes volatile solutes such as hydrogen sulfide, carbon di-oxide, methane, and volatile odorous substances such as methane thiol (CH3SH) and bacterial metabolites. Contact with oxygen also aids iron removal by oxidizing soluble iron (II) to insoluble iron (III). The addition of limes as CaO or Ca(OH)2 after aeration raises the pH and results in the formation of precipitates containing the hardness ions Ca+2 and Mg+2. These precipitates settle from the water in a primary basin. Much of the solid material remains in suspension and requires the addition of coagulants (such as iron III and aluminum sulphates) to settle the colloidal particles. The setting occurs in a secondary basin after the addition of CO2 to lower the pH. Sludge from both the primary and secondary basins is pumped to a sludge lagoon. The water is finally chlorinated, filtered and pumped to the city water mains.

 

 


Related Discussions:- Muncipal water treatment

File & chemical removal of gutta percha-endodontics, File  & chemical remov...

File  & chemical removal of gutta percha: -    K-type file & chloroform is the best choice in small and curved canals. -    The pulp chamber floated with chloroform, then k-typ

Proteins requirements for ulcerative colitis, Q. Proteins requirements for ...

Q. Proteins requirements for ulcerative colitis? Proteins: Patients with ulcerative colitis lose about 4-8 g fecal N2 as compared to the normal excretion of 2 g. In severe ulce

Define starch - carbohydrates, Define Starch - Carbohydrates? Starch is...

Define Starch - Carbohydrates? Starch is the major form of stored carbohydrate in plants. Starch, as you may already know, is composed of a mixture of two substances: amylose,

What is photoperiod, What is photoperiod? Photoperiod is the daily time...

What is photoperiod? Photoperiod is the daily time period of light exposure of a living being. The photoperiod might be vary according to the period of the year.

Why is there a sense of pressure change inside the ear, Why is there a sens...

Why is there a sense of pressure change inside the ear when someone goes down a mountain? The pressure inside the middle ear is keeps equal to the external ear (so to the exter

Examples of diseases normally spread by droplets, Q. (a) In droplet infecti...

Q. (a) In droplet infection (i) where do the droplets come from, (ii) what infective agents might they contain? (b) Give two examples of diseases normally spread

Feeding mechanism in holozoic organism, write short note on feeding mechani...

write short note on feeding mechanism in holozoic organism

Determine about the adequacy of children''s food, Determine the Adequacy of...

Determine the Adequacy of children's food? Adequacy of children's food and nutrient intake depends on: Sibling company Peer pressure Model set by parents and

Investigation of aortic regurgitation by exercise testing, Q. Investigation...

Q. Investigation of aortic regurgitation by Exercise Testing? It is helpful in assessing functional capacity, symptom status and hemodynamic effects in patients with severe AR

What do you mean by an antibiogram, Q. What is an antibiogram? The Anti...

Q. What is an antibiogram? The Antibiogram is a laboratory test intended to guide the choice of sufficient antibiotic to treat a given bacterial infection. In an Antibiogram cu

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd