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STP consultancy

STP consultancy and sewage treatment plant troubleshooting

Sewage treatment plants fail in a small number of recognisable ways, and almost none of them are the reason first offered. We investigate the plant as it is running, not as it was commissioned, and establish which of those ways this one is failing in.

The engagement, on one sheet
Investigate
the plant you have, as it runs
5 areas
an investigation looks at
Diagnosis
kept separate from what to do about it
Quoted
before any further work starts

Who arrives here

You are probably here because

If none of these is your situation, it is still worth a conversation: this list is not exhaustive.

  • The outlet is failing and the plant is under a compliance obligation, or has a notice from the pollution control board
  • There is an odour complaint from residents of a housing society or apartment complex, from occupants, or from a neighbouring property
  • The plant was sized for an occupancy the building has never actually reached, or has passed
  • The plant runs, but nobody can say whether it is working
  • An operator or contractor has changed and performance changed with them

What an investigation looks at.

Lines of enquiry, not conclusions. Which of them matters for your plant is what the investigation establishes.

Line of enquiry01

Load and hydraulics

  • Actual occupancy and diurnal flow pattern against the design population
  • Under-loading, which damages a biological process as reliably as over-loading
  • Retention time as built against retention time as designed
  • Infiltration, storm ingress and kitchen or laundry streams that were not in scope

Line of enquiry02

The biological stage

  • Aeration adequacy, blower duty, diffuser condition and dissolved oxygen through the tank
  • MLSS and sludge age, and whether sludge is being wasted at all
  • Settleability and sludge structure, including bulking and rising sludge
  • Anoxic and anaerobic zones where nutrient removal is required

Line of enquiry03

Odour

  • Whether the odour is septicity in the collection system or a process failure in the plant
  • Sludge holding time, and sludge left standing in a tank with no aeration
  • Venting, extraction and any odour control stage, where one exists

Line of enquiry04

Separation, disinfection and reuse

  • Clarifier or membrane performance, and blanket control
  • Filtration and disinfection contact time and demand
  • Where treated water is reused, whether the reuse quality is the real constraint

Line of enquiry05

Operation

  • Operator routine, competence and what is actually recorded
  • Standby equipment, and whether it has ever been run
  • Maintenance history against manufacturer intervals
What an engagement produces, level by level

Problems this usually arrives with.

Talk to an Expert

Bring us the symptom. We will find the cause.

Describe what the plant is doing, in your own words. You do not need to know the cause first.

Talk to an Expert

A specialist calls you and tells you the right next step and its cost.

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