The rapid population growth throughout the Southern African region has placed pressure on industry and institutions to manage wastewater more effectively. This has involved the upgrading of existing plants and pump stations and the installation of new reticulation systems. As a result, additional strain is being placed on existing design and maintenance resources in an industry already hard pressed for skills.

This is exacerbated by the speeds at which these installations need to come on line in order to cope with the backlog in wastewater and sewage handling, ITT Flygt business and unit manager of public utilities and wastewater Mark Hultzer tells Engineering News.

"This is a particularly sensitive issue within the public utilities sector, where pump stations are overburdened, resulting in overflows from these facilities into our ground water and water systems," he says. This is an everpresent reality as is regularly highlighted in the daily press.

Hultzer says that a variety of technologies are available to assist in providing appropriate solutions. Many of these are simple retrofits, or, in the case of the ITT Flygt TOP pump station, an entirely prefabricated pump station can be delivered to site and installed with relative ease.

The TOP turnkey concept is ideal when refurbishing old pump stations. ITT Flygt engineers can retrofit old stations with a TOP solution delivered as a kit, which is installed in the existing structure with minimum construction work. This turnkey wastewater pump station solution, once installed, eliminates the majority of problems currently being experienced at local facilities. These include crust build-up, floaters and sedimentation. In all three cases, the ultimate result is unpleasant odour emission and pump blockages.

The system's modular, flexible design comes in a range of sizes to suit depths of between 1,5 m and 6 m, and capacities between 4 l/s and 95 l/s. Hultzer says company engineers assist with calculating the dimensions of a customer's pump station and completing the order, which reduces the costs for project planning and installation.

Hultzer says that if wastewater handling applications are designed making use of ITT Flygt's clean-sump technologies, future maintenance and operating costs can be substantially reduced, which will contribute to the overall reduction of the total life-cycle cost of an installation. "However, if at the early stages of the design phase the issues of correct sump design and pump installation are not tackled it becomes that much more difficult to fix retrospectively as these installations cannot easily be shut down for civil changes, leaving the operator with a long-term problem of installation and the associated increase in maintenance operating and breakdown costs," he adds.

One of the main issues with sump management is to keep the solids in suspension or, when pumping, to resuspend these solids. This is accomplished in smaller sumps using a pump with a flush-valve- agitator, and in medium-sized sumps, a pump with a side-mounted mixer may be the appropriate solution. In very large sumps, permanently installed submersible mixers can be used to keep the solids in suspension at all times making it easier to pump away and keep the sump clean.

"What is important to comprehend is that through investing in technologies such as TOP or Clean Sump, the public utilities or industry concerned will actually be investing in significantly reduced total life-cycle costs as a result of the reduction in maintenance requirements and downtime," he says.

Hultzer also makes a strong case for the use of submersible solutions including both pumps and mixers. By installing submersible pumps and mixers there is a reduction in noise output, the smell and general cleanliness factor is improved and the need for expensive civils infrastructure is vastly reduced. ITT Flygt offers a wide range of submersible pumps suitable for varying application requirements.

ITT Flygt's product experts have extensive applications knowledge, especially in appropriate installation design to ensure optimum pump performance. Assistance in the selection of correct pumping equipment including pumps, mixers and ancillary equipment will further ensure this. The monitoring and control panels are custom designed and manufactured by ITT Flygt to support these technologies and protect the pump stations and its equipment.