Installation at a Glance

Before installation

• Installation should only be undertaken by a qualified specialist with appropriate professional indemnity insurance.
• Complete a proper site assessment before installation, including:
  • Soil/ground conditions.
  • Groundwater level.
  • Flood risk.
  • Existing and proposed ground levels.
  • Drain invert levels.
  • Potential additional/superimposed loads.
• Obtain the necessary Building Control and environmental approvals before installation.
• Confirm the HydroClear model and check all components against the delivery note.
• Determine whether the site is a dry or wet ground installation. If there is any doubt about seasonal groundwater levels, the wet-ground installation procedure must be used.

Choosing the location

• The treatment plant should be positioned at least 10 m from watercourses or other buildings, subject to site-specific requirements and approvals.
• Consider the inlet invert, drainage gradients and access for installation and future maintenance.
• Allow access for a sludge tanker, with the manual specifying a maximum hose distance of 20 m.
• Consider prevailing wind direction when choosing the location, particularly for future desludging and maintenance.
• The area around the tank should be protected from unauthorised access.

Vehicle loading & protected area

• Do not allow vehicles or other superimposed loads within 3 m of the tank.
• The protected area should be fenced off.
• If vehicle loading within this area is unavoidable, a qualified civil/structural engineer must design the installation so that loads are not transferred to the tank.
• The engineer should also sign off the installation.

Excavation & base

For a standard installation:

• Allow at least 300 mm of backfill around the tank.
• Provide a 150 mm thick concrete base beneath the tank.
• Concrete should be 25 N/mm² strength, with a 30 mm slump, and levelled to within 20 mm.
• The concrete base should extend at least 300 mm around the sides of the tank.
• Where difficult ground conditions exist, such as unstable ground or shrinking clay, allow an additional 250 mm excavation depth for hardcore and sand blinding.
• Lower the tank onto the cured concrete base and check that it is true and level.

Lifting & positioning

• Only lift the tank when it is completely empty.
• Use suitable, rated lifting equipment through the tank’s designated moulded sling slots.
• Do not use chains or wire ropes.
• Avoid sharp impacts during handling.
• Once positioned, secure or prop the tank as necessary to prevent overturning before the installation is stabilised.

Dry Ground Installation

A site is considered dry only where groundwater will not rise above the base of the tank at any time of year.

• If the surrounding ground is non-porous, such as clay or bedrock, water can collect around the tank.
• In these circumstances, provide a suitable land drain to ensure the installation remains free-draining, or use the wet-ground installation procedure.
• After positioning the tank, fill it to approximately 600 mm water depth.
• The Reactor/Media Chamber must be filled first to prevent buoyancy damage.
• Keep the liquid level in the reactor higher than the settlement chambers.
• Carefully consolidate concrete beneath the lower radii of the tank.
• Do not use a vibrating poker.
• Continue filling the tank while simultaneously backfilling with 12–15 mm washed, clean, chemically inert pea gravel/free of sharp edges.
• Maintain the water level approximately 200 mm above the external backfill level.
• Once filled to inlet/outlet height, connect the pipes and continue backfilling to approximately 100 mm above the tank body.

Wet Ground Installation

• Treat the site as wet ground if groundwater can rise above the base of the tank.
• If you are unsure of the groundwater level, use the wet-ground installation method.
• The maximum permissible water table is 1.7 m from the base of the tank.
• Provide suitable pumping equipment to keep the excavation free of groundwater during installation.
• Poor ground conditions may require planking, strutting and temporary shuttering.
• Allow at least:
  • 150 mm concrete below the tank
  • 300 mm concrete around the tank
• Lower the tank onto the cured concrete base and fill with water as specified.
• Place and consolidate concrete carefully around the tank, ensuring no voids remain.
• Do not use a vibrating poker.
• Maintain the water level approximately 400 mm higher than the external concrete level.
• Fill the tank to outlet-pipe height and bring the concrete to within approximately 400 mm of this level.
• Allow the concrete to harden for approximately 24 hours before continuing the installation.
• Once hardened, connect the inlet/outlet pipes and continue the concrete backfill, covering the top of the tank body with approximately 100 mm of concrete.

Pipework

• The recommended inlet gradient from the dwelling to the treatment plant is 1:40.
• 1:80 may be acceptable with Building Control approval.
• For gravity outlet versions, the outlet gradient should be approximately 1:80 minimum, subject to the specific installation design.
• If pipes are too shallow or pass beneath walls/foundations, they should be suitably protected.
• Ensure all pipework is correctly supported and free from obstructions before commissioning.

Blower & Electrical Installation

• The standard system requires a single-phase 240 V supply.
• Use a suitable 3-core steel-wire-armoured (SWA) cable.
• Provide a dedicated circuit with appropriate isolation and protection.
• The incoming supply must have a separate earth-leakage circuit breaker at the source building.
• The SWA cable must be correctly installed and the steel armour earthed at both ends.
• Electrical work must only be completed by a fully qualified electrician.
• Position the external blower housing at ground level close enough to the tank for the supplied airline to reach.
• Remove the perforated transport straps securing the compressor before operation.
• Keep the blower housing protected from direct sunlight where possible, as excessive heat can reduce diaphragm life.
• Keep the blower housing closed while operating.

Airline connection

• Feed the supplied airline through the blower housing gland.
• Connect it securely to the air blower using the supplied fittings and jubilee clip.
• Connect the other end to the airline connection on the tank.
• Route the required pipework/cables through the 110 mm service duct.
• Check all airline connections are airtight before commissioning.