It is of utmost importance that the maintenance of Water Treatment Plants and Effluent Treatment Plants be carried out so that they can operate efficiently, thus guaranteeing the quality of the treated water/effluent according to the specifications determined in the project, complying with the environmental legislation in effect or the quality standards required, where they will be used.

Besides an efficient operation, with the processes well controlled and monitored, the condition of the equipment and facilities must be in ideal conditions in terms of their state of preservation and operation.

For this to happen, it is necessary to implement a
maintenance management
that can guarantee, in a periodic and planned way, the execution of maintenance in the treatment plants, ensuring that all equipment and installations work in a satisfactory and continuous way.

The elaboration of a
maintenance plan
is the beginning of the whole process of maintenance management.

A maintenance plan is understood as a set of documents where all critical preventive maintenance activities are registered, their execution frequency, the location of the equipment, the specification of parts to be used, as well as the tools used and who are the professionals that are trained to execute the activities.

A good maintenance plan brings countless benefits, among them we can highlight:

  • The assurance of operational continuity;
  • The reduction of unscheduled downtime;
  • The reduction of costs with purchases of urgent materials;
  • The reduction in the cost of emergency overtime;
  • A greater durability of the equipment and installations;
  • The contribution to workforce safety.
ETA and ETE Maintenance


It is not a quick and easy task, as it requires dedication and technical knowledge of the maintenance processes.

To be a good preventive maintenance plan, it is essential that it contains the following information:

  1. The identification of the equipment (brand, model, manufacturer and other relevant information);
  2. The location of the equipment;
  3. The services that will be performed;
  4. The periodicity of execution;
  5. The professionals who will perform the activities;
  6. The resources required (tools, parts, consumables, support materials, among others);
  7. The time allotted for execution;
  8. Information about safety: PPEs and EPCs required; NRs applied to the activities, among other specific procedures that may be necessary;
  9. Environmental information such as the correct disposal of waste generated during maintenance.

For the elaboration of maintenance plans, various software and applications available on the market can be applied. The choice of which tool to use in the elaboration of maintenance plans will depend on the resources available, as well as on the degree of investment the company wishes to make.


It is not enough just to elaborate a good maintenance plan, it is necessary that it is put into practice in an organized, systemic and controlled way.

A flow chart of the maintenance planning process is shown below:

Maintenance plan flowchart

When it comes to preventive maintenance of water and wastewater treatment plants, some points must receive special attention:

  • Flocculators: the preservation of the physical structure of these tanks is very important to avoid corrosion, fissures, and cracks. Special attention should be paid to the agitation blades and propellers, and to the gear systems, which should always be well lubricated.
  • Agitators: Their correct operation is fundamental to the process. Pay attention to the lubrication of the gears, blades, and propellers, and always keep them well aligned, avoiding shaft warping.
  • Decanters: Usually composed of bottom and surface scrapers, and can be operated in a manual or automated way (solenoid valves, automatic drive valves). Such equipment can suffer greatly from corrosion, and the use of corrosion prevention procedures and products should be widely employed.
  • Filters: In a WTP/ETE we can have sand filters, carbon filters, nutshell filters, among others. This equipment requires special attention and periodic inspections to ensure proper operation and reliability in the process. Lubrication of the controls and moving parts should be regular.
  • Metering pumps: These are essential and very important pieces of equipment in the entire treatment process. Its operation must be reliable. Periodic maintenance and daily monitoring through a checklist are paramount activities.
  • Feed/transfer pumps and motors: Just as the metering pumps require assurance of reliable operation, the other pumps and motors in the unit must be periodically inspected and checked, following the maintenance plan. A daily visual inspection, either by the operator or by the maintenance professional, makes the difference, and often avoids unexpected downtime of this equipment.
  • Sludge dewatering equipment: Such as centrifuge, filter press, dewatering press. All this equipment requires a lot of attention regarding lubrication and periodic inspections of its components, according to the information available in the manufacturer’s manual. Pay attention to noises and noises that are considered abnormal. An intervention as soon as possible can avoid high costs.
  • Line analyzers: Among the most used are: pH, turbidity, alkalinity, conductivity, ORP. They must be cleaned and calibrated frequently. It requires special attention to the electrical contacts. The manufacturer’s manual should be used to develop the preventive maintenance plan.

In general terms, the implementation of maintenance management in water and wastewater treatment plants can be a differential and bring countless benefits, especially process stability, cost reduction, and increase in the useful life of the facilities.

Seeking to meet the needs of the market, the EP Groupthrough the EP Engineeringhas the 360° Solutionwith extremely qualified, dedicated, and experienced professionals, offering design and construction services for treatment plants, as well as operation, maintenance, and analytical monitoring, ensuring that your treatment plant can provide the best results in efficiency and operational cost.

Odair José Krause (

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