Drinking Water Treatment
NANDONI WATER TREATMENT WORKS
ENGINEERING PERSPECTIVE
Fresh water resources are fast becoming scarce with increasing demand, while the quality of raw water is deteriorating through the impact of pollution. Water transfer from somewhere “upstream of pollution” is increasingly unrealistic, as more and more people live downstream of human settlements. The proper approach is to consider the outlet of wastewater treatment as a source for drinking water production. Water Safety Planning, as per the World Health Organisation, guides risk management through the water supply chain, from catchment to consumer, to ensure drinking water of sufficient quality.
PROFESSIONAL SERVICES
Virtual Consulting Engineers provides services from strategic planning and design to construction supervision, commissioning, maintenance and operation. Our expertise includes:
- Instrumentation, motor control and process automation
- Pre-treatment, coagulation, flocculation and solids settling
- Slow sand filtration, rapid sand filtration and pressure filtration
- Disinfection through combinations of chlorination and ozonation
- Suspended and dissolved particle removal with special media filters, from microfiltration, ultrafiltration, nano-filtration to reverse osmosis
- Advanced oxidation through production of hydroxyl radicals for removal of trace organics and contaminants of emerging concern
We generally work according to SANS 241(2015) Part 1: Drinking Water Determinants and Part 2: Application. We are proficient in the use of the STASOFT computer program for softening and stabilisation of water, as well as a range of membrane model applications.
PROJECTS
SAPS Limpopo (2014)
Department of Public Works / South African Police Service
Rural police stations in Limpopo Province produce drinking water on site. Our work included repair and upgrade to the boreholes and water purification plants at 33 SAPS stations. With capacities from 20 – 100m3/d and ground water of varying characteristics, processes were designed for nitrate, iron and manganese removal, and hypochlorite disinfection.
Waterval, Ncome and Matatshe Prisons (2019)
Departments of Public Works / Correctional Services
Virtual Consulting Engineers was responsible for the design and construction supervision of the new Matatshe Prison water works with treatment capacity of 1,000m3/d. Raw water abstraction is from a river, followed by conventional treatment, including primary solids removal, rapid sand filtration, chlorination and a new product water storage reservoir.
Safe Water Africa (2019)
European Commission
Ten consortium partners developed new drinking water technology under H2020 grant agreement no. 689925. Virtual Consulting Engineers designed and constructed a demonstrator plant (10m3/d) at ERWAT’s Waterval Wastewater Works, to reclaim final effluent for drinking water production, through a series of pre-treatment units, nanofiltration, electro-chemical ozonation and advanced oxidation.
Rooigrond Prison Water Softening (2020)
Departments of Public Works / Correctional Services
Rooigrond Prison near Mahikeng receives bulk water from the Molopo River immediately downstream of the source, which is characterised by extreme hardness that leads to limestone scale formation and blockages in pipes. Virtual Consulting Engineers designed the lime softening plant with a capacity of 1,000m3/d to include a clariflocculator for removal of calcium and magnesium hardness.
La Nicolière Water Treatment Works (2024)
Development Bank of South Africa / Mauritius Central Water Authority
Virtual Consulting Engineers formed part of a consortium of companies to provide technical and financial advice on a Build Operate and Transfer contract to refurbish the existing drinking water treatment works (65Mℓ/d) and upgrade the total works to 120Mℓ/d, including cascade aeration, flocculation, rapid gravity sand filtration and disinfection.
Nandoni (2024)
Development Bank of South Africa / Department of Water and Sanitation
The Nandoni dam constructed in 2004 is at the heart of the greater Levhuvhu water scheme. Professional services included design of a Module 2 water treatment works for 60Mℓ/d, with raw water pump station, chemical dosing, coagulation / flocculation, clarification, sand filtration and disinfection. Work also includes a 3.5MW clear water pump station, followed by refurbishment of the existing 60Mℓ/d Module 1.