Compliance & sustainability
Sewage treatment plants: designed, built and maintained for your site
Packaged sewage treatment plants on the activated sludge process, engineered and maintained across South Africa — for municipalities, industrial sites and remote facilities the mains can't serve.
Not every site can send its sewage to a municipal works — and in South Africa, plenty of municipal works cannot take what is already arriving. A packaged sewage treatment plant puts the whole treatment train on the site that needs it: collection, aeration, settling and final disinfection, engineered as one compact plant that is designed, built and maintained by the same team.
Prosep's sewage treatment services are built on the activated sludge process — the same technology behind large municipal works, applied at whatever scale the duty demands. The process itself is natural; nature offers a unique solution to treat sewage cost-effectively. What makes a plant reliable is the engineering around it: how each section is arranged, sized and enhanced for the load it will actually carry.
The process
How a sewage treatment plant works: four sections, one train
Every packaged sewage plant we build runs the same proven train — sized and arranged for the site's actual load.
Collection & anaerobic treatment
A primary or interceptor tank evens out the feed to the aeration stage, retains large particles before they reach the process, assists denitrification, and stores the extra sludge the process generates — typically removed at six-monthly or annual intervals.
Aeration
A flat-bottomed aeration tank with an aeration ring at its base. Blowers and diffusers introduce air so that intimate contact is established between the air and the solid matter — the biology that does the actual treatment work.
Sludge settling
A settler tank produces a clear overflow liquid. We only use conical settler tanks — more expensive to manufacture, but no solids can collect in the bottom. Settled solids return to the process; left behind, they would turn anaerobic and cause foaming that ruins the effluent.
Polishing & disinfection
Where the outflow feeds dams or rivers, phosphates are removed by ferric chloride dosing and a second settler, then a chlorine or ozone contact stage brings the final effluent to the standard required for discharge or irrigation.
Specification
What's included, and how a plant is sized
The train is standard; the sizing and the options are specified against the load your site will actually carry.
Included as standard
- Primary / interceptor tank — evens the feed, retains large particles, stores surplus sludge
- Flat-bottomed aeration tank with aeration ring, blowers and diffusers
- Conical sludge settler with solids return — never flat-bottomed
- Chlorine or ozone contact tank for final disinfection
- Commissioning, operator handover and a maintenance schedule
Sizing & format
- Small and large plants on the same activated sludge process — the difference is the arrangement and enhancement of each section
- Sized against your measured or design flow and organic load, not a catalogue band
- Tank-based plant for small duties; larger multi-section arrangements where the load demands it
- Capacity and footprint stated per site in the proposal
Options & duty
- Phosphate settler with ferric chloride dosing where the outflow feeds dams or rivers
- Ozone in place of chlorine for the final contact stage
- On-site sludge drying beds producing a sterile, compostable dry mass
- Treated effluent to discharge standard, or reused for irrigation
Packaged sewage treatment plant: sections at a glance
| Plant section | What it does | Standard or option |
|---|---|---|
| Primary / interceptor tank | Evens out the feed, retains large particles, assists denitrification and stores surplus sludge for removal at six-monthly or annual intervals | Standard |
| Aeration tank | Flat-bottomed tank with an aeration ring; blowers and diffusers bring air into intimate contact with the solid matter | Standard |
| Conical sludge settler | Produces a clear overflow and returns settled solids to the process, so none collect and turn anaerobic | Standard |
| Phosphate settler | Removes phosphates by ferric chloride dosing and a second settler | Option, where the outflow feeds dams or rivers |
| Chlorine or ozone contact tank | Final disinfection to the standard required for discharge or irrigation | Standard (ozone as an option) |
| Sludge drying beds | Dry the plant's solids on site into a sterile, compostable dry mass | Option |
After commissioning
A plant is only as good as its maintenance
The solids the process produces are dried on site — a clean system of drying beds produces a sterile, usable dry mass for composting, and stored sludge needs removing only at six-monthly or annual intervals. Prosep maintains the plants we build, monitors the biology that does the work, and can assess and take over an existing plant that has been left to drift.
Who this is for
Anywhere the mains can't do the job
Municipalities adding capacity, industrial sites treating their own sewage, and remote facilities beyond the network.
Municipalities & sewerage
Packaged capacity alongside the works, plus the treatment chemistry behind it.
Sector pageIndustrial effluent treatment
Industrial wastewater to discharge limits — the process-side counterpart.
Related servicePotable water treatment
Drinking-grade water to SANS 241 for the same remote sites.
Related serviceHow we work
Assess, engineer, prove, monitor — the same discipline behind every plant.
Our methodStandards we work to
Where a plant's outflow feeds dams or rivers, phosphate removal and disinfection are required, and the final effluent is treated to the standard suitable for discharge or irrigation. The same team handles the industrial side of the same problem through industrial effluent treatment plants, and where a remote site also needs drinking water, potable water treatment to SANS 241 completes the picture. Every dose in this programme comes from Prosep's own range of water treatment chemicals, supplied with the dosing pumps and monitoring that make it hold.
The original Prosep brochure on packaged sewage treatment plants, which walks through the activated sludge process tank by tank, is free to download from our brochures and downloads page.
- DWS discharge requirements
- General Standard — discharge & irrigation
FAQ
Packaged sewage plant questions
What is a packaged sewage plant?
A complete sewage treatment works, engineered as a compact set of tanks and equipment that can be installed at the site that needs it — rather than piping sewage to a distant municipal works. Prosep designs, builds and maintains packaged plants on the activated sludge process, for both small and large duties; the difference lies in the arrangement and enhancement of the various sections of the process.
How does the activated sludge process work?
It is a natural biological process, engineered to run reliably. Sewage is collected and evened out in a primary tank, aerated so that micro-organisms break down the waste, and passed through a settler that separates the solids and returns them to the process. A final polishing stage removes phosphates and disinfects the effluent to the standard its destination requires.
Can the treated effluent be reused?
Yes — the final contact stage treats the liquor to a standard suitable for discharge into dams and rivers or for use as irrigation. The solids are also usable: a clean system of on-site drying beds produces a sterile dry mass suitable for composting.
Who are packaged sewage plants for?
Municipalities that need capacity alongside an existing works, industrial sites that treat their own domestic sewage, and remote facilities beyond the reach of a municipal connection. If your site generates sewage and the mains cannot take it, a packaged plant is the standard answer.
How much maintenance does a packaged plant need?
Less than most operators expect, if it is designed honestly. Stored sludge is typically removed at six-monthly or annual intervals, and the biology needs monitoring rather than constant intervention. Prosep maintains the plants we build — and can assess and take over the running of an existing plant.
A site the mains can't serve?
Tell us the load and the site. We design the plant around what will actually arrive, build it, commission it, and stay accountable for how it runs.