Filteration Plants

1. Check that the correct grade and size of sand and gravel are laid, as specified.  
2. Ensure that the rate of filtration is maintained constant since sudden variation in the rate of filtration may cause water to break through  the filtering material without proper treatment. 
3. When the loss of head in the filter has reached the permissible limit see that the filter is washed  after putting it out of commission. 
4. Ensure that no coagulants are used  preceding filtration by slow sand filters. Coagulants may however be used when filtration is through rapid sand filter or through pressure filters. 
5. For washing slow sand filter, scraper about an inch of sand from the top of the bed, wash it with clean water and return it to the filter. 
6. For back washing of rapid sand filters, ensure that the quality  of water for back washing is as good as that of the effluent from the filters. 
7. Avoid back washing the  rapid sand filter too vigorously as it would result in the sand entering the wash  water through. 
8. When air is used for agitation of sand (while the sand is suspended in rising water) ensure that the air and water are not applied simultaneously, because of the danger of disturbing the gravel. 

Chlorination 

1. Ensure that the work of installation of chronometer is carried out in accordance with manufacturer's  instructions and catalogue. 
2. A schematic diagram showing the various parts/operations of the chlorination should be prominently displayed in the chlorinator room. 
3. Ensure that apparatus for determining dosage of chlorine and the residual chlorine content (orthotolidine method, calorimatric method etc) are maintained properly. As the  dosage of chlorine varies according to the  quality and temperature of water, tests should be carried out as  a matter of routine to determine the correct dosage for the desired residual content. 
4. Ensure that anti corrosive treatment to cylinders and other equipments in the chlorinator room are given periodically. 
5. Ensure that the personnel permitted to handle chlorine cylinders and chlorinating equipments are made aware of the hazards involved, precautions to be observed and the first aid to be rendered in emergencies. 
6. Ensure that cylinders containing chlorine are handled gently  and not dropped or rolled on ground and no object is allowed to strike them with force. 
7. See that cylinders are not stored in the open or in damp places hut in rooks which are well lighted and ventilated. 
8. In case the valve is found stuck, no attempt should be made to ease the  same by hammering  as this is very dangerous. 
9. Ensure that  rubber gloves, gas masks  and aprons are housed in an easily accessible cupboard (unlocked) outside the chlorinator room  and the canisters of gas masks are changed at proper intervals. A record of this should be kept. 
10. Check for leaks should  be carried out frequently by using a glass rod dipped in a solution of liquid  ammonia which produces dense white  fumes in  the presence of chlorine gas. 
11. Grease should never be used where it can come in contact with chlorine. 
12. In case of injury caused to personnel by leakage of chlorine gas  send for the doctor immediately. It is important that no drink of any sort should be given, if  the person is unconscious. If breathing has  apparently stopped, artificial respiration may be given by the back pressure and arm lift  method. 
13. As disinfection is such an important step in water treatment, ensure that  the facilities exist for the switch over to the application of bleaching powder during availability of liquid chlorine.