Bushkoppie Wastewater Treatment Works for the Greater Johannesburg Metropolitan Council
This project called for a 200Ml/day extension to the wastewater treatment works with full biological nutrient removal. Raw sludge fermentation was used to produce volatile fatty acids to promote biological phosphorus removal.
Durban Water Recycling for OTV RSA Environmental (Pty) Ltd (now Veolia Water)
The contract called for tertiary wastewater treatment to convert raw domestic sewage into high quality water for industrial purposes (47,5Ml/d). The process includes coagulation with metal salt, lamella settling, CO2 buffering, dual media filtration, inter-ozonation, granular activated carbon contacting and chlorine disinfection housed in a multi-level, compact structure.
Villaperez Wastewater Treatment Works, City of Oviedo, Spain for Cadagua SA
This 120Ml/day biological nitrogen and excess phosphorus removal plant harnesses a maximum flexibility process design which enables the plant to be operated MUCT, UCT, Phoredox, JHB and MLE configurations.
Water Quality and Treatment
Clean water is vital to the health and well-being of all communities and environments. SSI excels in assisting clients to protect and preserve our precious water resources. Our expertise in water quality is achieved through development of sophisticated, yet practical, water quality models and innovative technological methods of predicting eutrophic and salinity profiles in receiving water. Water quality data is used to analyse water, identify trends, recognise potential problems, evaluate pollution control programmes and respond to emergencies such as floods. Our expertise in this area is based on extensive experience in dealing with severe salinity and eutrophication issues arising from a combination of warm climatic conditions, rapid urbanisation and industrialisation.
We offer the full complement of engineering services to mitigate risk to clients, improve reliability and reduce overall costs of systems and processes, including:
Water resource development and management
Water supply and effluent treatment for municipal and industrial applications using conventional technologies or advanced processes such as membranes, dual media and activated carbon filtration, softeners and a variety of chemical treatment and disinfection processes.
Pumping systems
System and process optimisation and design
Chemical and sanitising treatment processes including UV irradiation, ozone, chlorine, chlorine dioxide, flocculants, pH control, iron and manganese removal
Dams & Hydropower
SSI has designed more than150 dams, across a spectrum from arch type to concrete gravity, concrete buttress, earthfill, rockfill, masonry or combinations of these, to small low cost earthfill embankment type agricultural dams. We have commissioned more than 30 large dams including buttresses up to 44 m high, concrete mass gravity walls, double curvature arches up to 37 m high and various earthfill and rockfill walls - as well as a large geomembrane lined dam (4 million m²) and a dam featuring the then largest Hydroplus units in the world. Medium sized concrete masonry dams are also our speciality, as are economical masonry structures using labour-intensive construction methods.
We have also undertaken safety inspections for more than 25 impoundments - several classified as High Hazard Category III dams. SSI engineers in South Africa and Zimbabwe are certified Approved Professional Engineers for dam safety inspections and rehabilitation.
Our expertise incorporates:
Hydropower schemes
Dams
Hydropower schemes
Transference schemes
Projects
Mohale Dam Project, Lesotho Highlands Water Scheme, for Lesotho Highlands Development Authority (LHDA).
SSI’s involvement is as part of the design and construction stage joint venture, Mohale Consultants Group, MCG, comprising Harza Engineering (USA), Snowy Mountain Engineering Corporation (Australia), Highlands Engineering consultants (RSA), BKS Pty Ltd, Melis & du Plessis, Nippon Koei Co (Japan), SM Consulting Engineers (Lesotho) and SSI. The project incorporates a concrete faced rockfill dam approximately 145m high and a diversion system comprising two horseshoe shaped Diversion Tunnels with upstream and downstream cofferdams. The dam wall itself consists of an embankment containing some 7,2 million m3 of rockfill materials, with a concrete lined ungated spillway on the left abutment and a multiple draw-off compensation water intake structure and outlet works. This type of wall construction is unique to this part of the world but is well known and popular in China, Australia and North and South America.
The Braamhoek Pumped Storage Scheme (BPSS) for Eskom
The Braamhoek Consultants Joint Venture (BCJV) was established for the design of the BPSS and is an equal joint venture of the following three leading SA consulting firms: SSI, Knight Piesold and Arcuss Gibb. The BPSS will provide 1333MW of power and has an estimated project value of R5 billion. The BPSS is located within the Drakensberg mountain range and consists of the following basic components: an upper reservoir, a lower reservoir, an underground powerhouse complex with four reversible pump-turbines coupled directly to motor-generators and associated waterways that link the two reservoirs and ancillary works that include access roads, transmission lines and temporary and permanent infrastructure. Current program sees completion of detailed design and tender documentation by the end of 2006 whereafter construction will commence leading to commissioning in 2012.
[Only a site pic available for the Braamhoek project above]
Water Resources Planning
Africa is primarily a water scarce continent, subject to rapid development and this calls for the utmost prudence in managing available water resources. In response, SSI has developed a number of sophisticated, yet practical, water resource modelling tools. Principal among these is the Water Resources Simulation Model (WRSM2000) — the most widely used rainfall-runoff model in South Africa, currently also proving itself in other SADC countries. We’ve also developed a spectrum of other software programmes to deal with a range of water resource issues.
We have extensive experience of the Water Resources Yield Model, used to determine yield from a multi-reservoir system in complex water resource systems subject to competing water demands associated with penalty structures.
SSI has undertaken many hydrological and water resources projects for our national government and for water research and mining organisations throughout southern Africa.
Our expertise incorporates:
Water resource modelling and analysis
Hydrological analysis (large and small catchments)
Situation assessment studies and water resource surveys
Development of water resources software
Water quality model development
Hydraulics of river systems
Support disciplines
Projects
Updating of the integrated water resources of the whole of South Africa by means of the enhanced WRSM2000 model, for the Water Research Commission
This project involves updating the water resources of the entire country (previously done in 1990 - the WR90 project) using the enhanced WRSM2000 model. This model has been upgraded from being a surface water resources model to an integrated water resource model by including the groundwater — surface water interaction, streamflow reductions such as alien vegetation and afforestation and more advanced methodology for irrigation and wetlands. The model is still to be enhanced further by incorporating databases and a GIS Viewer and will ultimately be incorporated into a framework which will include water quality and Ecological Reserve models. The output from this study should greatly facilitate water resources studies across the entire country. This is an extremely innovative project which involves incorporation of leading edge technology in water resources and computer science.
Assessment of Water Availability in the Olifants Water Management Area (WMA) by means of Water Resource Related Models for the Department of Water Affairs and Forestry
This project involves a detailed study of the Olifants WMA using the enhanced WRSM2000 model to analyse the hydrology, the Water Resources Yield model (WRYM) to analyse the yields of dams, the Water Resources Planning Model (WRPM) to plan the future allocation of water, the Water Quality model (WQT) and various groundwater models to analyse water quality and groundwater respectively. These models require extensive collection, collation and analysis of water requirements for activities such as irrigation, mining, urban and rural development, Ecological, industry etc. on the one hand and the available water resources to meet the demand on the other hand. This project overlaps with the WR2005 project (detailed on this page) in that the integated water resource aspects provided for by the latest development of the WRSM200 model will be catered for.
Development of a Reconciliation Strategy for the Amatole Bulk Water Supply System for the Department of Water Affairs and Forestry
This project involves a detailed study of the Amatole region (the area covered by the Buffalo, Nahoon and Kubisi rivers) in terms of historical, current and future water requirements and the available water resources. Strategies are to be developed to ensure that there is adequate water up to the year 2030. All possible sources of water including surface and groundwater, re-use of effluent and water conservation and demand management are being taken into account and the study also includes an analysis of water quality, environmental impact, Ecological Reserve and institutional arrangements.
Community Upliftment
SSI has responded energetically, with dedication and innovation, to the need to provide adequate water and sanitation facilities in developing countries. Our contribution goes beyond engineering, to embrace social, environmental, facilitation and training issues, often within extremely constrained economic circumstances. Appropriate interventions have included low cost water supply and distribution systems, on-site sanitation, low volume flush toilets, small bore sewage reticulation and simple treatment systems in ponds or artificial wetlands and reed beds. We are committed to promoting sustainability within the constraints of limited resources. SSI has innovated customised capacity building programmes that put emphasis on the ability to upgrade.
Water Supply Systems
SSI has commissioned a large number of storage reservoirs varying from reinforced brick concrete to pre-cast and geomembrane lined earth impoundments, including the largest (4 million m3) and the deepest (27 m) geomembrane lined reservoirs in southern Africa.
We have also engineered a variety of conveyances, ranging from large scale inter-basin transfer pipelines and canals, to low cost rural water supply and irrigation schemes, implementing more than 20 000 km of major water pipelines and a similar length of bulk sewers and outfalls.
Our pumpstation installations vary from small local borehole supply systems to water supply components for major cities and large mines. We offer specialist skills in designing intakes for the exclusion of bed load material, which is of particular interest in Africa where rivers tend to carry heavy concentrations of sediment.
SSI has undertaken many projects implementing or upgrading existing reticulation and distribution networks, in both urban and rural environments. Our clients have derived additional benefit from the models developed in-house for distribution systems, which have been harnessed as effective management tools for water demand management and conservation.
Our expertise incorporates:
Reservoirs
Conveyance schemes
Pipelines
Irrigation schemes
Pumpstations
Water supply and sanitation planning
Distribution and reticulation pipework
Water Services Development Plans (WSDPs)
Water conservation and demand management
Pump system optimisation and design
Refurbishment of existing infrastructure
Projects
Emergency bulk water supply to Nokeng Tsa Taemane and Ekanustria for the for the Department of Water Affairs and Forestry and their implementing agent, Rand Water
As a result of a serious drought in 2004, this bulk water supply scheme had to be implemented in the shortest time possible. The final design, consist of two booster pumpstations, 39km of 500mm diameter steel pipeline and 10 pipe-jacked road and rail crossings. A major challenge on the project was that the tenders were invited within one month after appointment and closed three weeks thereafter, before the planning or design had started. While the envisaged source changed in this period from raw Roodeplaat Dam water to potable water from the Rand Water system, the length was also doubled and a second pumpstation added to supply the area north of Bronkhorstspruit.
Operation Gcin’amanzi in Soweto, Johannesburg, for Johannesburg Water
Based on the high unaccounted-for-water attributed to physical losses, lack of flow metering and misuse of potable water landing in the sewer network, Johannesburg Water had started with an initiative to correct the situation. For this project, all aspects of the water distribution network from the supply reservoir were addressed. Pre-paid meters were installed to all houses after an extensive information campaign, bulk flow meters were introduced, weak pipework replaced, closed valves located and opened and direct bulk supply points connected to the reservoir supply network. The work was handled with a contractor joint venture partner and a large number of local small contractors for specialist pressure testing and leakage detection work.
Lower Komati River small farmers development and irrigation scheme, for the Swaziland Development Agency
After the construction of the Maguga Dam, raw water was secured to irrigate nearly 10 000 ha along the Komati River in Swaziland. The Swaziland Development Agency was established to implement the full agricultural development including engineering (bulk river abstractions, conveyance, reservoirs and sand traps, booster and abstraction pumps, distribution pipes and irrigation systems) and the establishment, training and mentoring of emerging farmers. SSI was responsible with local partner SCE in a joint venture with Dhlamini Stewart Scott, with the engineering work over a six-year period for some 30 farmer associations
Institutional Development
Activities undertaken in this sphere include assisting formal and informal organisations, evaluating municipal service departments, presenting workshops to enhance decision-makers’ knowledge and skills in fields such as local government transformation, municipal services, housing, land use and transportation.
SSI’s solutions revolve around skills transfer to public sector officials and emerging practitioners, basic skills training and developing and supporting small contractors in projects involving installation and maintenance of infrastructure.
Wastewater Systems
SSI has designed hundreds of kilometres of pipelines for the conveyance of domestic sewage and industrial effluent. Conventional gravity sewers and outfalls range from ND 110 mm reticulation to greater than ND 1,5m, in all materials from PVC for domestic sewers to HDPE and steel for larger diameters. The firm also has experience with “small bore” systems that convey septic tank effluent by partial pressure or vacuum systems. Specialist structural services for bridges (e.g. river crossings) and flumes for flow measurement etc are catered for in-house. Pumped wastewater systems include all aspects of pumpstation design including optimisation of pumpstation layouts and lifecycle costs, ease of operation and full compliance with all relevant health and safety regulations. Mechanical and electrical engineering expertise is sourced in-house to provide clients with a “one-stop” service. Legal requirements for planned maintenance of municipal infrastructure (e.g. sewers) are catered for by using advanced CCTV techniques which can be used in GIS based systems, and SSI has experience in the rehabilitation of sewerage systems using trenchless technologies.
Our expertise incorporates:
Gravity sewer reticulation
Trunk and outfall sewers
Vacuum sewerage systems
Wastewater pump stations
Trenchless technology
CCTV inspection & verification and GIS interfacing
Rehabilitation of buried effluent pipes
Umlaas trunk outfall sewer for eThekwiniMunicipality (Durban) (Winner - SAICE Technical Excellence, 2005) As a result of the rapid development of low income group residential housing in the greater Welbedagt and Dassenhoek areas, eThekwini Municipality needed to provide bulk sewerage infrastructure to service the densely populated areas. An ND 800 sewer incorporating three major bridges to withstand 1:100 year floods was required and SSI provided integral pedestrian access into the bridge designs to allow safe community passage across the Umlaas River for the first time.
Reinforced concrete and ribbed HDPE pipes being laid at abutment to pipe bridge
Pipe bridge across the Umlaas River
– permitting safe pedestrian access across the river for the first time
New Industrial Effluent Pumpstation, for Mhlathuze Water, RichardsBay (project in progress)
Foskor, the biggest phosphoric acid manufacturer in the southern hemisphere, needs to disperse waste gypsum via a new sea outfall pipeline to the Indian Ocean. The existing pumps have to be upgraded to pump a mixture of sea water and gypsum slurry at 1 500 l/s @ 68 m (using 2 x 900 kW duty pumpsets in parallel plus 1 standby). SSI is providing the mechanical and electrical engineering services as well as carrying out the primary pumpstation civil engineering designs.
Existing industrial effluent pumpset (1 of 6) – to be replaced
Solid Waste Management The responsible handling of the waste that our society produces is imperative for sustainable development. Waste minimisation and reuse are becoming increasingly important and the need to look at alternatives to landfilling is becoming greater everyday. Dealing with waste is a largely behind-the-scenes operation. Landfills are not just holes in the ground where we dump our waste, but are high-tech engineered sites. The same goes for the collection and transportation of waste which can be highly complex systems. SSI has extensive experience in solid waste management and has been involved in numerous projects over the years.
Our expertise incorporates:
Landfill planning and design
Solid waste systems and optimisation
Waste minimisation and recycling
Metsweding Integrated Waste Management Plan (Metsweding District Municipality)
The existing waste system of the Metsweding District Municipality was not operating optimally and the landfills being used did not conform to the Department of Water Affairs and Forestry’s minimum requirements. In consultation with stakeholders, possible new landfill sites and transfer station sites were identified and the entire waste system was optimised over a 30 year planning horizon using a sophisticated computer programme, including the types and numbers of trucks, the positioning and selection of future landfills, transfer stations, garden waste depots and material recovery facilities. It was found that recycling and garden waste composting would cost only slightly more than landfilling all the waste and that there were many social advantages to recycling and composting through the creation of jobs.
Oatlands Solid Waste Landfill Site
SSI has completed the construction of Phase 3 of the Oatlands Solid Waste Landfill at Margate for the Hibiscus Coast Municipality. The previous phases were reaching the limit of their capacity and additional air space was required. Phase 3, independent from the first two phases, has its own leachate collection system and contaminated stormwater run-off dam. The available air space is about 180 000 m3. Filling operations commenced in March 2006 and the cell has an expected lifespan of about 4 – 5 years.
The cell lining was constructed using clay sourced locally on the site, compacted in layers with appropriate stone and geotextile leachate collection and leakage detection filter layers.
A future phase is being planned with a total capacity of about 1 600 000 m3. This will extend the lifespan of the landfill site by a further 15 years.
Photographs: Picture: Final construction of Phase 3 leachate collection layer comprising stone placed on geotextile filter fabric in foreground, with Phase 2 contaminated stormwater run-off dam in centre and Phase 3 contaminated stormwater run-off dam leakage detection layer under construction in centre right. Picture: Final construction of Phase 3 leachate collection layer comprising stone placed on geotextile filter fabric in foreground. In the background, the clay lined west bank is being covered with topsoil for grassing protection. Stormwater cut-off drain is visible at top of bank.
Ekandustria Solid Waste Landfill site
SSI has recently completed the rehabilitation and upgrading of a landfill site for the Ekandustria, Ekangala and Dark City areas. The landfill site was originally not well controlled and illegal dumping and burning of waste was occurring. The stormwater system was upgraded, an evaporation pond constructed and the landfill site reengineered to comply with the Department of Water Affairs minimum requirements. What was once a source of pollution and an eyesore in the area has now been cleaned up and is providing a much needed service to the community.
Picture: The Ekandustria Landfill Site prior to the rehabilitation by Stewart Scott International: an environmental and health hazard Picture: The Ekandustria Landfill Site after rehabilitation
TOWNSHIP SERVICES
SSI provides a full spectrum of residential services from site and service up to golf estates, commercial and industrial township infrastructure. Our services embrace water and sewer reticulation, pumpstations and outfalls, access roads and streets and stormwater drainage and management.
Our expertise incorporates:
Rural water supply, on site sanitation and gravel roads
Mass housing projects with individual waterborne services, a range of road options and stormwater drainage
Medium to high cost services
Townhouse developments
Luxury estates and high cost developments
Commercial and industrial township services
Projects
Reeston Phases 1, 2 and 3a: low cost township services for the BuffaloCityMunicipality
Provision of waterborne services, roads and stormwater drainage to 5,000 sites. SSI was involved as project manager and facilitator from the inception stage, to negotiate the level of service and to facilitate the provision of emergency temporary service while the permanent services were being provided. SSI succeeded in ensuring cost effective services in difficult terrain.
Macibini villages water supply: provision of a standpipe water supply to 3 400 people living in 12 villages for the ChrisHaniDistrictMunicipality
Services included proving the groundwater source and equipping boreholes, pumping mains, reinforced concrete reservoirs, gravity reticulation lines and communal standpipes. The quality of life in each village was dramatically improved as walking distances to collect water were reduced to 200m.
Dainfern – bulk water supply and internal services for JCI Properties
Services included a 500mm dia gravity water main and full services to luxury villages and cluster houses.
Industrial services for Middelburg Mine Services
In addition to medium cost residential services, full services were provided to the industrial areas, which included concrete block and in-situ concrete paved hardstanding areas, full reticulation and rail facilities for exporting coal.
