Attachment K - HSTP Design

6.0 DEFINITIONS

Advanced Secondary treatment system - These systems treat domestic wastewater to
10 mg/L BODs, 10mg/L TSS standard or better prior to discharge to the land
application area.

Biochemical oxygen demand (BOD) - A measure of the amount of oxygen used in
the biochemical oxidation of organic matter, over a given time and at a given
temperature; it is determined entirely by the availability of the material as a biological
food and by the amount of oxygen used by the microorganisms during oxidation.
Blackwater — Wastes discharged from the human body either directly to a composting
toilet or through a water closet (flush toilet) and/or urinal and the water used for the
discharge.

BOD; - BOD determined by standard test (5 days at 20°C).

Design Irrigation Rate (DIR) — The loading rate secondary or advanced secondary
effluent can be applied to the soil of a disposal system expressed in mm/week
Effluent — Sewerage, water or other liquid partially or completely treated or in its
natural state flowing out of a septic tack, aerated wastewater treatment system, sand
filter or other treatment system or treatment component.

Expected available area — Areas, which at the time of evaluation have no physical
constraints to inhibit the design, instillation, operation and maintenance of disposal.
Expected design area —Where the absorption field and its reserve are to be installed.
Greywater — The domestic wastes from a bath, shower, basin, laundry and kitchen but
excluding toilet and urinal wastes.

Intermittent watercourse — A natural or artificial stream or channel, identifiable by
recognisable bed and banks, along which rainwater or storm water usually or
occasionally flows.

Land application area — The area over which the treated effluent is evenly applied.
Land application facility/system —Is a facility for further treatment, re-use or
sustainable disposal of effluent from a treatment plant on land under controlled
conditions.

On-site sewerage treatment plant — Includes septic tanks, aerated wastewater
treatment plants, sand filters, wet composting toilets etc.

Permeability — (P - m/day) calculated value derived from the rate at which a head of
liquid is absorbed into a soil.

Reserve Area — an area set aside for future use as a Land Application Facility to
replace or extend the original system.

Secondary treatment system - These systems treat domestic wastewater to 20 mg/L
BODs, 30 mg/L TSS standard or better prior to discharge to the land application area.
Sewerage - The wastewaters from the community, including all faecal matter, urine,
household and commercial wastewaters that contain human waste.

Surface Horizontal Setback Distances — Separation distances from watercourses,
dams, drainage channels, bores, wells, boundaries, paths, dwellings etc.

Total suspended solids (TSS) - The portion of total solids retained on a glass fibre
filter with a nominal pore size 2 microns, measured after being dried at a 103-105°C.
Vertical Setback Distances — Separation distances from permanent watertable or
bedrock.

Wastewater — The spent or used water from human or household or commercial and
institutional activity that contains dissolved or suspended matter (sewage).

 

Unearthed Geotechnical P/L. 12 Design Report 023-038