The members of Green Hippo Innovations have been involved in various Water Research Commission projects. Some of these include:

Project Tilte and Report Nr Description

Quantification the influence

of air on the capacity of large

diameter water pipelines and

developing provisional guidelines

for effective de-aeration


The results are discussed in the

following reports:


Volume 1: WRC Report no. 1177/01/03


Volume 2: WRC Report no. 1177/02/03

The contents of Volume 1 comprises:
•Influence of air on pipelines
•Field investigations
•Experimental work
•Numerical modeling of air release from pipelines (CFD)
•Effective de-aeration of pipelines
•Further developmentsVolume 2, includes the following sections:
•Intrusion of air into pipelines
•The consequences of air in pipelines
•Hydraulic transport of air
•Air valves
•Implementation of a new pipeline
•Sizing and positioning of air valves
•Typical installation details of air valves
•User comments

Review of factors that influence

the energy loss in pipelines and the

procedures to evaluate the hydraulic

performance for different internal



WRC Report no. 1269/01/06

The geographically mismatch of the water demand centres and the water resources necessitate the transport of water over long distances and high elevation differences. On average water is transported about 350 km in South Africa (Basson, Van Niekerk & Van Rooyen, 1997). High energy costs and the increasing demand require that the water transfer infrastructure should function optimally. Since the 1930’s various researchers contributed to the identification and development of factors and relationships to quantify the energy loss in pipelines, which led by 1958 to the development of pressures, head losses and discharge relationships (Chadwick and Morfett,1999) for the design and evaluation of pipes and pipe systems.

There are various factors that influence the hydraulic capacity and pipeline designers need to take all of these into consideration during the design. For instance the estimation of roughness parameter for a pipeline has a significant effect on the hydraulic capacity and operational costs. An underestimation of this parameter can be catastrophic when the required demand cannot be met. The better quantification and identification of these factors required investigation, reviewing the available literature, conducting experimental investigations, perform field investigations and develop software that will assist designers in evaluating a pipeline system over its full life cycle.

The aims of the study were:
•The quantification of the factors influencing the friction loss in pipelines.
•Establish the relationship between water quality, operating conditions and

the hydraulic performance of different liner systems and pipe materials.
•Development of selection criteria for liner systems and pipe material.
•Quantify the economic influence of increasing friction losses in a pipe

•Development of a computer model to evaluate whether to replace,

refurbish or extend existing infrastructure components.
•Establish the effectiveness of different pipe rehabilitation options on the

friction loss characteristics and liner integrity.

The potential application

of Genetic Algorithms in

the water industry


WRC Report no. 1144/01/01

The past decade marks the development of computational capacity that far exceeds the capacity of the “instructor” to define options to be evaluated when optimisation has to be achieved.

The Government’s objective to provide “water for all” made it essential that the limited capital has to be employed to provide the maximum benefit. The optimal decision in terms of expansion, addition or rehabilitation of water supply systems has to review the conflicting demands and select a cost effective and efficient solution.

Within the context of water supply, there are numerous variables that can

influence the selection and hence the final cost of system improvements.
These variables include:
•The high variance in rainfall and runoff,
•the availability of alternative water supply,
•the demand pattern variability,
•the operational ability of the system,
•the maintenance requirements,
•the running cost-especially power cost and
•the affordability and willingness to pay for services.

The determination of the optimal selection of system components requires techniques that can be employedto assist the decision-maker in finding the appropriate solution within the environment of all the possible solutions

(Solution space).

The aim of this study was to evaluate the application of genetic algorithms in the optimisation of different components of water supply projects, viz:
•pump selection and scheduling
•optimal pipeline diameter selection
•valves and surge alleviating devices selection
•management of water supply projects
•alterations and extensions required in the upgrading

of the capacity of water supply infrastructure.

Application and conceptual

development of genetic

algorithms for optimization

in the water industry

This study evaluated the application of genetic algorithms in the optimisation of different components of water supply projects and conceptually developed the procedures for the implementation thereof. Based on the available literature study, as well as the feedback from water supply authorities, the need for the application of GAs as an optimisation technique in the water industry was defined. The potential applications of

GAs in the water industry in South Africa are:
– Hydrology and water resources assessment,
– Network optimisation,
– Optimisation of rehabilitation, extension and upgrading of distribution networks during the planning and design phase,
– Operation and maintenance scheduling

This study objective was to provide the conceptual development of procedures to implementGAs as an optimisation technique for water resources assessment and network optimisation.

Grouted lining systems for

the renovation of old steel

pipelines and the design of

new pipelines

In South Africa steel pipes have been installed as late back as 1930.

Steel pipes amongst other need to be protected against corrosion. This is normally achieved by the provision of an internal lining and external coating. Some of the liner systems that have been used in the past have to be replaced and in the case of Rand Water the largest water utility, consideration is given to install grouted viscous-elastic liners in a number of their pipelines to extend their useful life. Practical challenges exist to install liners at joints, bends, pipe transitions, fittings, branches and at valves. In selecting a liner, one of the major aspects to consider is whether the pipeline still has sufficient structural capacity for the intended use. The structural contribution of the different layers in the composite pipe influences the buckling characteristics of the pipeline. Thus the objective of this study was to investigate alternative lining systems applicable for South African conditions.

The experimental work involved the following:

  • Establish the ease of installation for liners which

could be used for steel pipelines;

  • Test the installation of joints;
  • Establish how the liner performs under high

internal pressure; and

  • Determine if the liner could be installed along bends.

Through the experiments the study has demonstrated that HDPE liners do have potential in the rehabilitation of steel pipelines, since they also provide some structural strength and possible ease of installation, as well as overcome some of the problems associated with current lining practices. The study has shown that more work needs to be done on the use of the materials on pipe bends and other fittings.

Influence of Catchment

Development on Peak

Urban Runoff

The research reviewed catchment response due to urban development on the basis of comparative assessment. This required the identification of similar rainfall in the catchment during different development stages for which gauged flow rates were recorded. The hypothesis which was reviewed here relates to the statement that urban development which creates more impervious areas on the one hand also generated longer times of concentration due to the changes in the length of the flow path as well as more temporal storage capacity which could result in a higher groundwater recharge.

The hypothesis that the influence of urban catchment development will decrease the peak runoff has neither been proved nor disproved.

Waterborne Sanitation Design Guide


WRC Report no. TT 481/11

This report summarizes the available knowledge, information and advancements of all waterborne sanitation systems used in South Africa.

The objective of the report is to provide a concise guide for the analysis and design of waterborne sanitation systems.

The four main waterborne sanitation systems which are described in this

guide are:

  • Conventional gravity sewer
  • Vacuum sewer systems
  • Small-bore sewer
  • Simplified sewerage

A summary description with advantages and disadvantages of these systems is provided. A technical design criterion for designing each of these systems is given with a worked example guiding the designer through the process to be followed.

Waterborne Sanitation Operation

and Maintenance Guide


WRC Report no. TT 482/11

The function of a waterborne sanitation system is to collect and convey wastewater in a hygienic manner. Operation and maintenance of this sewer system means making sure that all its components are kept in good operating condition. Planners, designers, the construction team and the administrators have a joint duty in providing an efficient system.

The operator can then, based on the available resources provided, operate and maintain the system. Municipal sanitary sewage collection and conveyance systems are an extensive, valuable and complex part of the country’s infrastructure. The waterborne sanitation system consists of pipelines, conduits, pumping stations, pressure mains and other facilities used to collect the wastewater from residential, industrial or commercial sources and convey it to treatment facilities. The public expects these systems to function effectively at a reasonable cost. Information has been synthesized from a wide variety of sources and tailored to South African conditions to produce a comprehensive guide on operation and maintenance of waterborne sanitation systems. Some sources of information were heavily relied upon in creating this guide. These include the document Alternative Sewer Systems (WEF Manual of Practice, 2008); the NEIWPCC (2003) manual entitled Optimizing Operation, Maintenance, and Rehabilitation of Sanitary Sewer Collection Systems; the Sanitary Sewer Overflow Solutions – Guidance Manual (ASCE, 2004); and the Sewer Design Manual (Bureau of Engineering, 2007).

This document comprises the following sections:

Types of maintenance

  • Equipment required for maintenance
  • Maintenance requirements and frequency
  • Operational requirements
  • Safety measures and practices
  • Inspection forms and checklists
Patent Title Description Picture
 Rotoscope  Real time monitoring of Biofilm growth  
 Cavitation prevention in control valves  Prevention of cavitation in control valves

by means of air induction