Drain smells from grease build-up — solved permanently with biology

Everyone knows the scenario: the kitchen drain smells of rotten eggs or stale grease despite the sink being clean. The trap gets cleaned — and the odour returns within days. The real cause sits further down the pipe: a biofilm of grease, soap, hair and dead bacteria that has built up in the first 50–100 cm of the household drain and continuously produces hydrogen sulphide (H₂S).

H₂S forms when sulphate-reducing bacteria reduce organic sulphur compounds under anaerobic conditions. Those conditions arise precisely where grease deposits block oxygen access. H₂S at concentrations from 0.5 ppm is clearly perceptible as a rotten-egg odour. From 5 ppm it can cause headaches and nausea in sensitive individuals — particularly in poorly ventilated kitchens or bathrooms.

In rental apartments and residential buildings with shared drain stacks, the problem compounds: the biofilm from a single household burdens the entire vertical drainage run. Odours travel back through traps into flats, blockages form at constrictions in the stack, and property managers face constantly recurring complaints and plumbing costs.

Chemical drain cleaners — Drano, drain unblocker gels and comparable products — contain sodium hydroxide (NaOH) or potassium hydroxide (KOH) as active ingredient. These strong alkalis saponify fat, dissolve hair and break down organic deposits. It works — once. The problem: the same alkali attack completely destroys the protective biofilm in the drain pipe, attacks PVC seals and adhesives with repeated use, and kills all beneficial bacterial cultures that would normally support the pipe's self-cleaning capacity.

Eco-test evaluations of chemical drain cleaners in 2025 repeatedly awarded "Unsatisfactory" overall ratings — not only for environmental damage in wastewater (NaOH is lethal to fish at concentrations from 0.4 mg/l) but also for real injury risk during handling: splashes in the eyes can cause permanent corneal damage; skin burns develop within seconds.

The biological dilemma: regular use of chemical drain cleaners repeatedly destroys the natural microbial protective layer in the pipe. In the subsequent "empty" phase without functioning biology, pathogenic organisms and H₂S-producing bacteria re-colonise the freshly cleaned pipe walls particularly fast. The next odour recurrence is guaranteed — and arrives sooner than last time.

lipasanF® works preventively, not reactively. Instead of dissolving an existing blockage, it prevents one from forming. The specialised microbial culture in lipasanF® establish themselves in the pipe wall biofilm, continuously produce lipases and enzymatically cleave fat molecules before they can combine into stable deposits. The biofilm remains alive — but biologically healthy rather than H₂S-producing.

Application is simpler than chemical alternatives: 50 ml of lipasanF® weekly, in the evening after the last washing-up or shower, poured undiluted into the drain. No protective gloves, no ventilation, no waiting time. After 2–4 weeks the odour begins to measurably diminish — not because a symptom was treated but because the cause is being biologically broken down.

For those switching from a chemical cleaner: the first two weeks may show a brief intensification of odour — remaining NaOH residues are neutralised by the biology while the new culture establishes. From week 3–4 the difference is typically clearly perceptible. A one-off initial dose (150–200 ml) accelerates the start-up phase.