As with any other equipment the lifespan of individual parts of the WWTP varies. The main part of the WWTP, i.e., the actual plastic tank, including the roof and lid must meet a minimum lifespan of 25 years under the most unfavorable conditions to obtain the CE mark. In most cases, the lifespan will be even longer, typically 30, 35, or more years. The oldest plastic WWTPs of similar construction were produced before 1989 and are still in the ground.
- In addition to the main structure, the WWTP consists of internal technology, which is usually plastic pipes, nozzles, and hoses that harden and become brittle over time. The lifespan of these components is about 10 years, after which all the technology can be quickly and easily replaced.
- The aeration plastic membranes, which supply air to the water in the form of fine bubbles, have a shorter lifespan within the internal technology. The lifespan declared by the manufacturer is 10 years and they can be easily replaced.
- Other mechanical components in the WWTP are electromagnetic membrane blowers and air solenoid valves. The lifespan of both the blower and valves is considered to be 8 years, although they often function for up to 15 years in practice.
- Regular service of the blower should be accounted for, involving the replacement of coils every 4 years and membranes every 2 years.