16-001014-02A (Ultimate SCMMP)

                                                                                                                               HumeGard® GPT
Standard HumeGard® (HG18 – HG45)                             Maintenance frequency

The standard HumeGard® consists of an internal               It is recommended and good practice for an inspection
separation channel and holding chamber.                      of the HumeGard® to be carried out on a quarterly basis.
                                                             The quarterly inspection is to check the operation of the
A specially shaped boom, which is supported by hangers       boom, volume of pollutants in the holding sump, etc.
hinged to the upstream wall, diverts material entrained      But generally, only an annual maintenance period for
in the flow from the separator to the adjacent, off line,    cleaning is anticipated.
holding chamber. This consists of the holding sump and
another baffle/weir/channel arrangement designed to          It is important during the quarterly inspections to check
retain floating material while guiding flow through to the   that the operation of the boom is satisfactory. The boom
outlet.                                                      should not be impeded by large pieces of litter i.e. logs,
                                                             etc. or have objects lodged underneath the boom or
• Low/Treatment flow operation                               between it and the baffle plate that may prevent it from
  During low to moderate flows, the boom remains on          rising, or sitting flat on the false floor.
  the floor of the separation channel and imparts an
  upward and sideways motion to the incoming flow.           Cleaning maintenance frequency requirements will vary
  This action causes deflection into the holding chamber,    with the amount of stormwater pollution generated in
  where heavy and saturated materials settle to the          your catchment (amount of litter, sediment, etc.). So it
  bottom of the sump, while buoyant material is trapped      is recommended that as the 3-monthly inspections are
  behind the baffle wall arrangement.                        performed, the frequency of maintenance be increased or
                                                             reduced based on local conditions and pollutant capture
• High/Bypass flow operation
                                                             rates.
  During infrequent high flows, the boom lifts, which
  permits the flow to pass beneath it while continuing to
                                                             The need for maintenance can be determined easily by
  deflect buoyant material to the holding chamber. Once
                                                             inspecting the unit from the surface by:
  the pipeline flows full, the boom lifts clear, allowing
  unobstructed flow through the unit, whilst at the same     • Checking if litter can be readily seen in the holding
  time retaining the floating materials on the upstream        chamber once the cover has been removed.
  side of the device.                                        • Using a dipstick or sludge judge (sediment sampling
                                                               tube) to assess how much sediment or organic
                                                               material has been captured in the bottom of the
Figure 2 – Standard HumeGard® - low flow conditions            holding chamber. A sediment depth over 400mm
                                                               would indicate cleaning is recommended to minimise
                                                               the potential for scour.


                                                             Sediment sampling tubes are available for purchase from
                                                             Humes (contact your local sales rep for more details).


                                                             Occasionally it may be beneficial to only remove captured
                                                             litter and not siphon the entire contents of the holding
                                                             chamber.




                                                                                                           HumeGard® GPT   4