Home | | Environmental Engineering I | Water Treatment Plan

Chapter: Environmental Engineering : Water Treatment

Water Treatment Plan

Multiple Barrier Principle: need to have more than a single process during treatment prevents breakdown in one process leading to complete treatment failure source must be well protected.



Section Key points OHP


Introduction -need to treat all surface waters and some groundwaters contamination may be microbiological, chemical or physical microbiological contamination is most important as it causes highly infectious disease with short-term impacts chemical contamination tends to have longer term effects on health suspended solids affect microbial survival and the acceptability of water always disinfect water supplies and maintain a residual in the water for protection against contamination during distribution and storage


Multiple Barrier Principle


need to have more than a single process during treatment prevents breakdown in one process leading to complete treatment failure source must be well protected


Treatment processes


many processes available, the suitability of each is a function of source quality, operator capacity and financial resources technology selection must be made on the basis of the above to ensure sustainability often need to reduce turbidity before treating water as this may interfere with treatment prefiltration is a physical process which removes suspended solids prefilters can be horizontal, vertical upflow or vertical upflow-downflow main advantage is limited working parts and doesn't use chemicals disadvantages include poor ability to remove fine material, microbial removal poor and may need frequent cleaning sedimentation is achieved by the settling of particles in slow moving water simple sedimenters do not use chemical coagulants and are not effective in removing fine material


Section Key Points OHP


Settling is improved through addition of coagulants to form larger aggregates which speeds up settling and removes fine material


modular and plate settlers improve settling efficiency


alum is the most common coagulant, others include


polyelectrolytes and ferric salts such as sulphate and




Advantages include removal of fine particles, removal of some viruses, quick, compact disadvantages include expense, need for good monitoring capacity, need trained operators




Sand filtration can be rapid or slow


Slow sand filtration is a biological process and rapid sand


filtration a physical process


Slow sand filters a biologically active top layer called the schumtzdecke which is composed of predatory bacteria


Schumtzdecke kills bacteria and viruses


Require cleaning @ every 2 months, take 3-4 days to recover


Rapid sand filters work at much faster rates and remove suspended solids


Advantages of slow sand filtration include production of good quality water, relatively simple to operate


Disadvantages include large land requirement, labour intensive, requires low turbidity water


Advantages of rapid sand filtration include small land requirement




Study Material, Lecturing Notes, Assignment, Reference, Wiki description explanation, brief detail
Environmental Engineering : Water Treatment : Water Treatment Plan |

Privacy Policy, Terms and Conditions, DMCA Policy and Compliant

Copyright © 2018-2024 BrainKart.com; All Rights Reserved. Developed by Therithal info, Chennai.