Sewage Treatment Process

Sewage treatment processes from Veolia Water Technologies South Africa help municipalities deal effectively with sewage water, as well as deliver a range of opportunities for water reuse and resource recovery.

We help clients enhance sanitation and reduce the ecological impact of our towns and cities with sewage treatment processes that meet the most stringent environmental regulations.

Our sewage treatment processes draw on our portfolio of over 350 proprietary technologies to cover the complete wastewater treatment cycle:

  • Primary treatment
  • Secondary treatment
  • Tertiary treatment & reuse
  • Sludge treatment
  • Odour control
  • Sewage treatment chemicals

Veolia is a worldwide leader in sewage treatment processes:

  • Over 62 million people connected to wastewater systems
  • Over 3 500 wastewater treatment plants managed
  • 350+ proprietary treatment technologies developed over our 160-year journey

Let us help you implement the sewage treatment process your operation needs for maximum efficiency. Send us an enquiry today!

The Complete Sewage Treatment Process: An Overview

Primary treatment

The sewage treatment process begins with removing large solids and particles from in-flowing wastewater. Clarification and filtration is used to make the wastewater more homogenous and thus downstream treatment steps more efficient.

Secondary treatment

Aerobic and anaerobic bacteria, nitrates, BOD (biochemical oxygen demand) and COD (chemical oxygen demand) form the basis of the secondary sewage treatment process. A biological digestion process, secondary treatment breaks down organic matter into a form that is easier to remove from sewage water.

Tertiary treatment & reuse

The tertiary phase of the sewage treatment process describes final disinfection of the feed water once the most hazardous bio-wastes have been removed and/or recovered. Water processed through tertiary treatment is ready to be used again – either as industrial process water or, if upgraded further, as potable water!

Sludge treatment

Solid contents removed from municipal wastewater have a range of valuable reuse properties. Veolia helps turn this sludge into a resource, including as agricultural grade fertiliser and bioplastic, which can generate revenue and subsidise the operating costs of the sewage treatment process.

Alternative treatments of municipal wastewater sludge can produce energy that can be used in the operation of the plant or even produce excess energy that can be fed into the municipal grid.

Odour control

Our sewage treatment processes include solutions for both physical / chemical deodorisation processes (that transform odorous gasses into a liquid), as well as a green biological control (that uses bio-filtration to oxidise such molecules into liquid).

Sewage treatment chemicals

Veolia’s Hydrex™ chemical range is a critical part in meeting maximum sewage treatment process efficiency. Hydrex™ 6000 chemicals include emulsions; organic and inorganic coagulants; and powders and beads, delivering state-of-the-art clarification, wastewater chemistry and application exposure. Hydrex™ 7000 chemicals – our biocides range – deliver broad activity and legionella control. They include oxidant and non-oxidant products; continuous and shock agents; rapid action and slow release products; and broad spectrum products.

Contact Veolia today, we’ll help you integrate an optimum sewage treatment process for your application!

Case Studies

Goreangab Water Reclamation Plant – Windhoek

Veolia has played an important role in helping Windhoek become a modern sustainable city with its central role in the New Goreangab Water Reclamation Plant, which has been re-using the city’s wastewater since 2001. The high-tech wastewater treatment and processing plant recycles wastewater and semi-purified sewage to a standard that is 100% safe for human consumption.


The plant, the only one of its kind in the world providing potable water commercially on such a large scale, supplies 21 000 m3/day to serve the City of Windhoek – about a third of the city’s total potable water supply.

Durban Water Recycling Project

Veolia’s design and construction of the Durban Water Recycling (DWR) Plant is a landmark achievement in sustainable sewage treatment processes and water use in Southern Africa. For the last 15 years, the plant has treated 47.5 Ml/day of domestic and industrial wastewater to near potable standards for use in industrial processes by high volume companies such as Mondi Paper and SAPREF.

It has meant this volume of water that was previously drawn from the city’s potable water supply is freed up for use by the city’s growing urban population, reducing the strain on the city’s overall water supply infrastructure. The pollution load on the marine environment where the wastewater was previously discharged is also significantly reduced.

We’ll help you implement the sewage treatment methods you need for maximum efficiency. Send an enquiry today!

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