the best-kept water treatment plant will occasionally develop problems,
such as a flocculator breaking down or the finished water quality
dropping. It is the operator's responsibility to ensure that the
plant continues operating in the face of these problems. This
will introduce to you to a problem-solving pathway that you can use
problems occur at your treatment plant.
Identify That There Is a Problem
This step may seem self-evident, but it can actually be the most
step in the entire problem-solving process. In order to recognize
there is a problem occurring at the treatment plant, the operator must
familiar with how the system operates. He must know how the
electrical, and mechanical processes work so that he will notice any
in operation. He should be familiar with the maximum contaminant
of all of the parameters imposed by state and federal regulatory
as well as with the typical levels of each of these parameters in his
The operator of a water treatment plant
which treats groundwater notices during his routine water tests that
turbidity in the finished water is rising. Although the turbidity
still well below the maximum contaminant levels, it is above the
finished water quality for his plant. He has successfully
the first step of the problem-solving pathway by identifying that there
Pinpoint the Problem
determining that there is a problem
at the plant, the operator must pinpoint the exact cause of the
The following steps can be used to narrow down the search for the
- Use your knowledge of the
The same problems typically occur over
and over again at water treatment plants. Problems associated
events such as heavy rainfall, spring and fall turnovers of lakes,
from the dam, and algal blooms happen at many treatment plants as
regular, seasonal events. Daily logs are a good source of
to refer to when attempting to determine the source of such
The logs can also tell the operator what has worked to solve similar
in the past.
Personal experience is another excellent resource. The operator
should pay close attention when problems do arise and note how they are
in order to be more prepared for the next situation. Before any
occur, he should build his own knowledge of how the plant works by
questions of his supervisors, reading the on-site manual, and observing
various components of the plant.
In the case of our example, the operator knows that the source of his
plant's water is a well which has not been under the influence of
water in the past. Since the daily log for the last couple of
shows no seasonal turbidity problems, he decides that the problem is
likely to come from within the plant.
- Check the most basic components
The next step is to check basic
of plant operation for any problems. The operator first checks
raw water quality, in case surface water has gotten into the
supply during a recent heavy rainfall. However, the raw water
has not changed.
Next, he checks the chemical feed rates throughout the plant. If
the amount of coagulant or other chemicals being fed has changed, he
this could affect the finished water quality. However, the
feed rates are the same.
Third, the operator checks critical systems throughout the plant.
He visually inspects the pump to see if it is indeed pumping, then
sure the pump control is set to internal, not external. He
inspects to see if the coagulant is reaching the feed point (the
static mixer) by unhooking the line momentarily. He checks the
line for leaks and makes sure that all ball valves are in the open
(valve handle parallel to the pipe.) Finally, he checks to ensure
the flash mixer, flocculators, and filters are operating.
Since none of these factors seem to be contributing to the problem,
the operator moves on to the next step.
Since there is no obvious cause of the
problem in the basic plant operation, the operator next checks to see
the high turbidity could be a sampling error. In his plant, water
is sampled continuously by a surface scatter turbidimeter. So he
the turbidimeter to make sure that the turbidity readings are
He inspects the turbidimeter for built-up solids or excessive turbidity
the bottom housing, for condensation on the bulb and lens, and to see
the proper amount of water is circulating through the
If necessary, he cleans the unit and adjusts the flow of water through
In this case, the operator finds no problem in the turbidimeter.
The operator should now use his
of the plant to narrow the search for the problem's source. The
water turbidity is normal, the coagulant is being fed into the water
and all pieces of equipment seem to be operating. So the problem
lie between the flash mixer and the clear well.
The most likely location of a turbidity problem is in the filters, of
which this plant has two. If the water leaving both filters has
turbidity, the problem is likely to be improper feed, high raw
high color content (due to algae), or even high metal contaminants such
manganese. Manganese can pass through the filters undetected and
in the clearwell showing turbidity in the finished water.
However, in this case, the operator notices that the treated water
out of one filter is normal while the turbidity is high coming out of
other filter. So he suspects that the second filter is in need of
Visually inspecting the top of the filter shows him that sludge has
up on the top of the media. The pressure gauge at the back of the
is high, indicating that the filter has neared its filtering
By checking the logbook, he can tell that this filter is nearing the
of its normal filter run between backwashing.
The operator now suspects that the high turbidity in the finished water
is due to a filter in need of backwashing.
To make sure that his analysis of the
problem is correct, the operator pulls a water sample from the back of
suspect filter to run in the lab turbidimeter. Testing shows that
water coming out of the suspect filter has a high turbidity while the
coming out of the other filter does not. This confirms his
and the operator concludes that the cause of the problem is a filter in
the problem, the operator should take action to solve the
Then he should double-check to ensure that his action actually had the
In the case
of our example, the operator solves the problem by backwashing the
After backwashing, he sees that the finished turbidity has returned to
normal level, so he knows he has solved the problem.
The example we have given dealt with
a commonplace occurrence at a water treatment plant which had a very
solution. Other common problems, such as power outages and
leaks, may have more complex solutions. SOP's, or standard operating procedures, are
lists of the steps that should be followed in various circumstances to
problems in water treatment plants. SOP's should be up-to-date
easy to understand and should always be readily accessible to the plant
Know When to Call
Despite the utility of SOP's, there are so many unique problems which can occur in a water
plant that it is impossible to have written documentation for all
experienced operator will be able to solve the majority of the problems
his plant, but in some cases he may not be able to pinpoint or solve
problem. Whatever the situation, he must not allow the problem to
If he is unable to correct the problem after an initial investigation,
should call the manager and follow the manager's instructions.
When calling for help on a problem, the operator should
be as honest and accurate as possible. Even if he thinks that the
is caused by his own error, it is better to say so and solve the
than to hide his culpability and allow the problem to continue.
When dealing with serious problems, the operator should
make an effort to remain calm. The manager may tell him to turn
the filters before the clearwell is contaminated and then to turn off
high service pump. The first responsibility of any water
plant operator is to deliver safe, potable water to his customers, and
should keep this goal in mind at all times. By following the
steps in this lesson, the operator can achieve his goal.