What to do if the circulating water is dirty
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The circulating water in our plant is too dirty, which often leads to blockages in small pipes and in the water-cooling jackets. What should be done to address this issue? At present, the chemicals we are using are mainly bactericides and corrosion inhibitors
A side filtration device can be used to filter the circulating water.
The contamination of the circulating water can be attributed to the following reasons: 1. Whether the system discharges waste water as designed – generally, the amount of waste water discharged is 3-5% of the volume of circulating water; in abnormal situations, this figure can increase to 10%. 2. Whether the bypass filtration system is functioning properly; it’s easy to overlook issues such as inadequate backwashing of the bypass filtration system or overly long backwashing intervals. 3. The quality of the raw water does not meet the design requirements; in such cases, increasing the amount of waste water discharged or using bypass filtration can help address the problem. 4. There are leaks in the system, allowing process fluids to enter the water system – in such situations, it is recommended to carry out repairs.
One more point: whether the selection and dosage of biocides, corrosion inhibitors, and scale inhibitors are appropriate.
Is there a problem with the formula of the pesticide?
The substance that blocks the small pipes and water-cooled jackets – whether it’s soft or hard, whether it has an odor or what color it is – wasn’t mentioned by the original poster, so it’s difficult to determine whether it’s scale, sludge, or something else
Can a stripping agent be added to the system on a regular basis? Is there bacterial analysis conducted to determine whether the amount of bactericide added is appropriate? Is the size of the side filtration tank appropriate, and is it operating properly?
There’s some truth to what you say! :Victory: But what you said, that “the general waste discharge amount is 3-5% of the circulation volume,” is unreasonable; generally, 1-2% is already a very high figure!
In muddy water, flocculants and filtration devices are needed; in harder water, scale inhibitors are required
Personally, I estimate that the phenomenon of frequent blockages in small pipes and water-cooled jackets mentioned by the poster is likely caused by sludge. The formation of sludge is mainly caused by inadequate use of biocides, which is reflected in aspects such as whether the biocide formulation is appropriate, whether the dosing is proper, and whether water is drained according to the water quality conditions after dosing (especially whether a large amount of water is changed after adding a descaling agent). The so-called bypass filtration for circulating water, as well as regular waste discharge, are also very important. The treatment capacity of the side filtration is about 5% of the circulating water volume. Additionally, adding a certain amount of dispersant also plays a role in treating the turbidity and sludge in circulating water. This post was last edited by Tan Zhaofeng on 2008-2-20 at 17:00.]
Increasing the amount of wastewater added for replenishment, adding bypass filtration, and making more use of water treatment agents can help solve the problem; in some cases, improvements are also needed in the processes and equipment! :)
Regarding the idea of increasing wastewater discharge, I have my own opinion: after the addition of disinfectants, the quality of the circulating water does deteriorate, and it is necessary to discharge wastewater or even replace a large amount of water in order to restore the water quality to acceptable levels. However, in order to control the concentration ratio of the circulating water, when the water quality meets the required standards, it is necessary to regulate the amount of wastewater discharged from the circulating water. When the turbidity or suspended solids in the circulating water are high, bypass filtration should be used to improve the situation, thereby controlling the concentration ratio of the circulating water, reducing water usage, saving on water treatment costs, and facilitating the control of microorganisms.
Is the bypass filter in the original circulating water system a pressure-type filter? With such filters, if automatic control is used, the set values can deviate significantly over time as operation continues. Based on what the poster mentioned regarding the dirtiness of the circulating water, I believe it is caused by high turbidity; it is recommended to replace the bypass filter with a gravity-type valveless filter； Let the equipment adjust itself according to the water quality, and the percentage of bypass filtration can be increased appropriately based on environmental conditions. For example, in the 7.5M cement waste heat generator set I built, I set the percentage of circulating water used for bypass filtration at 8%. This is just my personal opinion