Wastewater

Sewerage design covers the collection and conveyance of wastewater from new lots to the existing reticulated network. This includes gravity pipe networks, manholes, and (where gravity drainage is not achievable) pump stations and pressure mains. The design must meet the network operator's standards and have sufficient capacity for the development.

We start by establishing the capacity of the receiving network and the connection point. We then design the internal gravity network, sizing pipes for the calculated peak flow with appropriate freeboard. Where gravity drainage is not possible, we design pump stations and rising mains. All designs are submitted to the network operator for approval before construction.

Wastewater design follows the network operator's engineering standards, which typically reference NZS4404, the Water New Zealand guidelines, and the relevant infrastructure design manual. Orogen designs to the specific standards of each network operator in our area and maintains current knowledge of any updates.

If the existing network cannot accommodate the additional flow from the development, a network upgrade is required. Orogen assesses the receiving network capacity at the feasibility stage and advises on the likely cost and scope of any upgrade required. This cost can be significant and affects the viability of the development.

We prepare the design to the network operator's standards, submit for their technical review, and manage the approval process. For larger developments, we arrange pre-design meetings with the network operator to confirm expectations before finalising the design. This avoids costly redesign after the operator's review.

Yes. Gravity networks are the standard and preferred solution; pressure networks using pump stations and rising mains are used where gravity drainage is not achievable due to topography. Orogen designs both, and advises on the relative costs and maintenance implications of each option.