Water Services Corporation architect Mario Balzan has won an award in the Infrastructural and Engineering class of the Malta Architect Awards 2016 for the work he carried out to plan, introduce and execute horizontal directional drilling and micro-tunnelling for large projects in Malta.

The ‘New Water’ reclaimed water project being carried out by the WSC will supply high-quality water reclaimed from wastewater for agriculture, industry, landscaping and other uses.

However, this water needed to be piped to consumers through roads full of traffic and through locations of great natural and archaeological value. The solution was to carry out six kilometres of HDD in the north of Malta andtwo kilometres of micro-tunnelling in the south for ‘non-man entry’ trenchless pipe-laying. This is a first in Malta.

The cost of these works was around €10 million, most of which was financed by the EU through ERDF 125.

Mr Balzan said that these trenchless systems were found to be very practical solutions in the local context, since practically nobody was aware of the considerable work going on below ground without disrupting both traffic and the top ground. The only locations which were temporarily disturbed were the pit sites, which were eventually reinstated.

A length of pipe about to be pulled into the HDD drilled bore, thereby laying new infrastructure without any trenching works needed.

For the micro-tunnelling in the south of Malta, concrete pipes of 1,600mm diametre, grade C60, were lowered one by one and thrust through the launching shaft and eventually pushed until reaching Ta’ Barkat and Sant’Antnin respectively.

Micro-tunnelling allowed the corporation to design the system to work by gravity instead of pumping, thereby saving a lot of energy had normal trenching been used.

For the north project, which used HDD, six kilometres of flexible 450mm HDPE pipes were used. This length of pipe was pulled from one location to another below ground as opposed to the ‘pushing and jacking’ micro-tunnelling system.

The WSC’s use of micro-tunnelling and horizontal directional drilling has demonstrated the corporation’s willingness to both create and adopt new technologies in search of ever greater efficiencies.