Treatment Plant Assessments

TREATMENT PLANT ASSESSMENTS

Assessments of treatment plants may be carried out for a number of different reasons

1.  Routine assessments often carried out by water suppliers to ensure performance is efficient and optimised

Assessments may also be undertaken when there is a failure in water quality or a failure to produce water of adequate quality.

3.Assessments involve the evaluation of each unit process to ensure that it performs efficiently and to identify any process failures and causes of failures

4.Aassessments should also evaluate the suitability of combinations of technologies (e.g. sometimes find simple sedimenters combined with slow sand filters when turbidity was relatively high - led to failure)

WATER TREATMENT PLAN

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