Breña was the first of the 49 districts of Lima in which Sedapal has evaluated the drinking water distribution systems and the collection of wastewater to identify pipe sections that need to be replaced or conditioned.

This article describes the main actions carried out to evaluate the existing needs of the water and drainage systems; the set of conditioning techniques without ditch that were considered in Breña and the techniques of the system of Technology Without Ditch that were selected for its use in this district. .

THE EVALUATION
The evaluation of the existing water and drainage systems included the following:

• Topographic surveys ;
• Population, demand and flow studies ;
• Inventory and evaluation of the conditions in the existing pipes ;
• Hydraulic models of the water and drainage systems ;
• Geotechnical studies ;
• Available alternative study ;
• Preparation of contract documents ;
• Preparation of maintenance and operation manuals .

This evaluation determined that the water system had approximately 74 km. Pipes, from which 57 km. (77%) required to be replaced or conditioned. It was determined that the drainage system had approximately 72 km., from which approximately 11 km (15%) required to be replaced or conditioned.

Once the magnitude and the condition of the existing systems were known, the next step was to evaluate all the options available. Since there are areas in the district of Breña with high traffic, Sedapal and Consorcio Greeley & Hansen-Caem Ltda., put the priority considering the techniques of Technology Without Ditch.

THE TECHNOLOGY WITHOUT DITCH

The Technology Without Ditch is a set of methods, materials and equipment used to condition the existing pipes or to install new ground pipes with a minimum of problems and destruction typically linked to the conventional methods.
The term “Technology Without Ditch” is relatively new. It has been used during the last 10 years globally to describe this strong and dynamic segment of the construction ground industry. The main methods of technology without ditch for conditioning purposes are the following:

1.-Cured in place pipe ( CIPP).

CIPP involved the construction of a new pipe within the host pipe existing in the work site, inverting a flexible hose that has been impregnated with a resin. When the resin is restored through the use of vapor and pressure, the plastic pipe is formed.

2.- Foid & Formed( F&F).

F&F means to modify the form in which the circular plastic pipe to a U form to facilitate its installation within the existing host pipes. When the folded pipes are in place, heat and pressure are used to unfold such pipe to be adapted against the host pipe.

3.- Slipining( SL).

SL includes the installation of a partial or continuous layer in the pipe within the existing host pipe. This method results in an important reduction in the cross section of the host pipe. The annular space between the inserted pipe and the host pipe is filled with a cement mortar.

4.- Pipe Bursting( PB).

PB involved the bursting of the existing pipe, pushing the destroyed pieces in the surrounding, simultaneously installing a new pipe, coupled to the element that is bursting the existing pipes.

5.- Point Source Repair( PSR).

PSR is the use of robots, remote control inflatable caps, short lining of cured in place pipe, etc. to repair punctual problems.

6.- Cement Mortar Lining( CML).

CML It is the procedure to push a rotating tool through the pipe at a controlled speed to apply the desired thickness of cement mortar on the walls of the existing host pipe, which has been previously scraped and cleaned.

TECHNOLOGY SELECTED FOR BREÑA .-  

The Technologies With Ditch executed in the district of Breña, being it the drinking water system, the total length of the pipe to be intervened in this district is 56.7 km which will be conditioned through the cleaning and lining of cement mortar; 6.4 km were replaced through the bursting of pipe and 9.7 km were replaced through the traditional method of open cut.
The drainage system used a total of 11 km of pipes in the district of Breña, from which 4.2 km were replaced through the pipe bursting and 6.8 km were replaced through the traditional method of open cut.

CONCLUSIONS

The work performed in the district of Breña represents the first application of two main Technologies Without Ditch (this means, Pipe Bursting and Pipe Lining with cement mortar).

The easiest scope would have been to continue with the same type of pipe replacement that has always been used, but Sedapal and the Consorcio Grecley & Hansen-Caem Ltda are not looking for the easiest solution, but the best .

The best solution for Breña was the selection of methods that were proven to be the most efficient and economical, which minimize the problems for the neighbors and the existing traffic. This was achieved with the use for the first time in Peru of the Technology Without Ditch.