Vacuum toilet systems, in addition to being relatively quick and easy to install, can achieve enormous water savings, resulting in significant environmental and economic benefits.

As cities around the world expand there is an increasing burden on key infrastructure, including water supply systems and waste water treatment and disposal.

If less water is used then the volume of waste water that must be treated is also reduced, so vacuum sewerage systems can form an environmentally responsible solution.

Some five years ago construction of the major Frei Caneca Shopping Mall and Convention Centre, which included a vacuum sewerage system, was completed in the bustling Brazilian city of Sao Paulo.

World Plumbing Review decided to take a look at how the 6-storey project was conceived and developed and, in particular, the effectiveness of the EVAC vacuum sewerage system after five years of operation.

Sao Paulo-based consultancy Procion Engenharia undertook hydraulic and electrical systems design for the Frei Caneca project.

A partner in the firm, Luiz Costi, says that right from the start the project presented major challenges.

“Several difficulties had to be addressed, including limited access through narrow streets, and space restrictions during construction due to the building occupying the complete dimensions of the ‘L’ shaped property,” he said.

“The logistics of construction proved to be a major challenge for the project team, as did negotiations regarding numerous legislative requirements.

“Difficulties were also encountered by the commercial team in selling space in the new venture due to the depressed economic conditions in the country at the time, and competition from nearby shopping facilities.

“I will always remember my partner, Levon Sevzatian, coming into our office with the plans for the new job. He was excited but also conscious of the responsibility of the technical design group, telling me, ‘We must think as a team; we will not have space for mistakes or delays, or isolated ideas, we need consensus. It will be the only way to success.’”

“The project consists of 74,000m2 (almost 800,000ft2) of construction with five levels of parking and one level for a supermarket below ground level. Above that, the mall consists of three levels with 182 stores, including one level to accommodate six movie theatres, restaurants, and a theatre and television school. Then, level four is the convention centre, level five is the main theatre, and the top level is for the administration and a heliport.

“In early 2000 the group started to discuss the concept for the structure. Until then we did not have much experience with steel structure, even though Brazil is a major producer and exporter of steel.

“Most of our construction projects had involved concrete structures. However, after considering the reduced lead-time, design requirements, and production, transportation and mounting constraints, our destiny was sealed.

“Codema Metalic Structures produced the metal pieces 400kms (248 miles) from Sao Paulo, and the pieces were assembled within four months.

“The natural technical choice was the use of dry wall (plaster board) to simplify the mounting of hydraulic and electrical systems. This would also reduce assembly time, and the impact of weight on the structure and foundation."

Keeping water costs down

“To encourage prospective tenants, the team was looking at ways to keep ongoing costs down.