Biological septic system excavation in Corfu

Groundwork for a biological treatment unit

Where there is no municipal sewer, many homes, especially newer builds and holiday rentals, use a compact biological wastewater treatment unit instead of a simple septic tank. In Greece these are commonly called a 'viologikos' (βιολογικός). They treat household sewage with air and bacteria, but they need to be set in the ground properly.

That is our part. We dig the pit for the unit to the depth and size the manufacturer and your engineer specify, cut the trenches for the inflow, the outflow and any power and air lines, and prepare a level, stable base. After the unit is placed, we backfill around it in layers with the required bedding material, and dig the inspection chambers and the trench for the treated-water discharge or irrigation.

The unit's selection, approvals, electrical connection and commissioning belong to the supplier or a licensed installer. If you have a high water table, ask them about anchoring: an empty tank in wet ground can float. See also septic tank excavation for simpler tanks and trenching for the pipe runs.

What's included

• Pit excavation to the manufacturer's and engineer's dimensions
• Level, firm base prepared for the unit
• Trenches for inflow, outflow, air and power lines
• Backfill around the unit in layers with the specified material
• Inspection chambers and discharge or irrigation trenches
• Surplus soil and spoil hauled away

How the job works

1. Get the specification

   Your supplier or engineer gives us the unit dimensions, the depth, the levels and the pipe routes.

2. Excavate

   We dig the pit and trenches, keeping the sides safe and the base level.

3. Unit set and connected

   The supplier or installer places and connects the unit, and anchors it if needed.

4. Backfill and finish

   We backfill evenly around the unit in layers, dig the chambers and discharge lines, and restore the ground.