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What is the range of effective size of sand particles (mm) used in slow sand filters?

What is the range of effective size of sand particles (mm) used in slow sand filters? Correct Answer 0.25 - 0.35

Explanation:

Slow sand filter

Rapid sand filter

Low Rate of Filtration (100 - 200 l/hr/m2)

High Rate of filtration (3000 - 6000 l/hr/m2)

Larger surface area (200 - 2000 m2)

Smaller surface area (80 - 200 m2)

Larger total depth (3 - 3.5 meters)

Smaller depth (2.5 - 3 meters)

Pre-treatment not required

Pre-treatment compulsory

Post-treatment optional

Post-treatment compulsory

Sand filter characteristics

Grain size - 0.20 to 0.40 mm

Coefficient of uniformity (grain) - 1.8 to 2.5

Sand filter characteristics

Grain size - 0.35 to 0.55 mm

Coefficient of uniformity (grain)- 1.2 to 1.8

Drainage: Lateral Drainage System

Drainage: Central Drainage System

Hence, the most appropriate answer is option 1.

Related Questions

Assertion A: Slow sand filters are more efficient in removal of bacteria than rapid sand filters.
Reason R: The sand used in slow sand filters is finer than that in rapid sand filters
Select your answer based on the coding system given below:
Which of the following statements are correct pertaining to the value of uniformity coefficient Cu for filter sand? (1) For slow sand filters, Cu = 1.8 to 2.5 (2) For rapid sand filters, Cu = 1.3 to 1.7 (3) For slow sand filters, Cu = 1.3 to 1.7 (4) For rapid sand filters, Cu = 1.8 to 2.5
Consider the following statements in respect of slow sand filter and rapid sand filter: 1. The two filters differ in respect of the standards regarding the non-uniformity of the sand used in their filtering media. 2. The two filters do not differ in respect of the effective size of the sand used in them. 3. The two filters differ in respect of their respective under-drainage system. 4. The two filters differ in respect of their respective rate of filtration. Which of the above statements are correct? 
Cleaning is done by
(i) Scraping and removal in filters slow sand
(ii) Back washing in slow sand filters
(iii) Scraping and removal in filters rapid sand
(iv) Back washing in rapid sand filters
The correct answer is
Assertion A: Slow sand filters are more efficient in removal of bacteria than rapid sand filters.Reason R: The sand used in slow sand filters is finer than that in rapid sand filtersSelect your answer based on the coding system given below:
Cleaning is done by (i) Scraping and removal in filters slow sand (ii) Back washing in slow sand filters (iii) Scraping and removal in filters rapid sand (iv) Back washing in rapid sand filtersThe correct answer is
The effective size of sand particles used in slow sand filters is
Consider the following statement. i. The slow sand filter is not efficient in removing turbidity ii. The slow sand filter has a high initial cost iii. Skilled supervision is required in slow sand filter Which of the above statement is/are correct?
On which of the following parameters are the slow sand filters better than rapid sand filters?
In comparing slow sand filters (SSF) and rapid sand filters (RSF), which of the following is an incorrect statement