BDBiodisc 25 Person Spares

Check the data plate on the tank or control panel, which usually shows the model, serial number and year of installation — Biodisc units have gone through several design revisions over the years. If you're unsure, send us a photo of the plate and the component you need replacing, as bearings, motors and media packs aren't always interchangeable between production runs.

The gearbox and motor take the most wear as they run continuously to rotate the biozone disc pack, so these are the parts most often replaced. Bearings, drive chains or belts, and the media discs themselves (if cracked or fouled beyond cleaning) are the next most common failure points. Diffuser and air-related components can also degrade over time depending on the specific Biodisc configuration fitted.

Basic items like external covers, fixings or a replacement diffuser can often be swapped by a competent homeowner. However, anything involving the motor, gearbox, electrics or work inside the tank should be carried out by a qualified wastewater engineer, both for safety (confined space, electrical) and to avoid invalidating any warranty or service contract. Most manufacturers also require annual servicing by an approved engineer to maintain compliance with your Environment Agency discharge consent.

Manufacturers typically recommend a service at least once a year, in line with British Water's Code of Practice for domestic sewage treatment plants and most Environment Agency permit conditions. Regular servicing catches worn bearings or a slipping drive early, before it leads to reduced treatment performance or complete rotor failure. Neglecting this can result in poor effluent quality and a plant that fails to meet its discharge consent.

Many core components such as bearings, seals and standard motors remain compatible across several generations of the Biodisc 25, but casing, media packs and control panels have changed with different production batches. If your plant is older or you're not sure of its exact model year, it's worth confirming compatibility with us before ordering to avoid a part that doesn't quite fit.

Commonly needed items like motors, bearings and diffusers are generally held in stock for fast dispatch, as we know a failed treatment plant isn't something that can wait. Less common or older parts may need to be ordered in from the manufacturer, so it's worth calling ahead to confirm current stock before you're without a working system. In the meantime, avoid excessive water use to prevent the tank overloading while the plant is offline.