Attachment K - HSTP Design

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1.0 INTRODUCTION

In accordance with the relevant codes, standards and Noosa Councils guidelines
Unearthed Geotechnical P/L was commissioned to undertake a Site and Soil
Evaluation at Lot 12 SP139169 (*71) Coveys Road, Tinbeerwah.

The results form the basis of our recommendations for the on-site treatment and
disposal of wastewater from the proposed four bedroom house and shed on this
10.768 hectare allotment.

A representative of Unearthed Geotechnical P/L was met and shown to the proposed

site by the owner, S Fleming. Our site investigation fieldwork was performed on
3/03/2023 after some recent rain activity in the course of the preceding weeks.

11 Referenced Standards.

Queensland Plumbing and Wastewater Code

AS/NZS 1546:2012 On-site Domestic Wastewater Treatment Units
AS/NZS 1547:2012 On-site Domestic Wastewater Management

AS/NZS 3500 Standard Sewerage Law Plumbing and Drainage Code
AS 1319 Safety Signs for the Occupational Environment

AS 2698 Plastic Pipes Fittings for Irrigation Rural Applications

1.2 Report Limitations.

Field Test Limitations The soil profiles detailed in this report should be
representative of the soil conditions over this site. In some cases conditions can
change dramatically over short distances. If site works reveal soil conditions that are
different from those shown in the attached data, the evaluator must be informed
immediately as changes may be necessary.

Client Supplied Information we have considered the information supplied to us by
the client. Should the client have omitted to supply us with relevant information or
supplied us with incorrect information our assessment may be irrelevant and/or
inappropriate. We do not take responsibility for the consequences in such cases and
may incur additional costs if as a result; more testing or re-writing is necessary.

1.3 Copyright.

The drawings, specifications and other documents provided by Unearthed
Geotechnical P/L remain the property of the Unearthed Geotechnical P/L. Upon
receipt of full payment for our service the client is licensed to use the drawings,
specifications and other documents for the work/s for which they were commissioned.
They shall not be used for any other work except by agreement with Unearthed
Geotechnical P/L. Copyright in all the drawings, specifications and other documents
remain the property of Unearthed Geotechnical P/L.

 

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2.0 SITE AND SOIL EVALUATION

The field and officework undertaken for our site and soil evaluation consisted of

a desk top study in accordance with the regulatory authority,

a comprehensive site assessment to record topography, geography and geology,
the confirmation of expected available areas and delineation of exclusion areas,
the assessment of site exposure and suitability,

a detailed subsoil investigation recording characteristics and limitations,

the determination of Soil Category, Colour, Texture, and Structure,

the determination of Indicative Drainage and Permeability,

soil observation boreholes (75-100mm dia. Jarret style hand augers),

the calculation of the Design Irrigation Rate (DIR),

the collation and evaluation of the results from the above studies.

Be Se Be Se Se He He Be Be He

(The test locations were not professionally surveyed and should be considered approximate)
(All fieldwork performed in accordance with the relevant Australian Standards and Codes)
(All boreholes backfilled in accordance with Occupational Health and Safety regulations)

The purpose of this site and soil evaluation is to ensure that a suitable Land
Application Facility is selected for this particular site.

In compiling this report we have assessed the existing and historical parameters to
gain a comprehensive overview of the potential for on-site domestic wastewater
management. The scale of, and methodology of our site and soil evaluation is
considered to be adequate, relative to, and indicative of the size of the facility, having
considered the consistent natural soil profile and the availability of suitable land.

     
        

i tered tor’ (QBCC 740251)
Unearthed:G 6 ehitiical P/L.
Ne

A full copy of this report and all the accompanying sketches plans details and notes shall be
made available to all present and future owners and or occupiers of the proposed house and
shed that are to be serviced by this Land Application Facility, and to all
contractors/suppliers/installers for quotation and or construction objectives.

 

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3.0 DESIGN DETERMINATION

We have determined the soil to have the following characteristics

 

Soil Characteristics (AS/NZS 1547/2012)

 

 

 

 

 

 

 

 

Borehole Nos 1 and 2
Depth (mm) 0- 300
Soil Category 3
Indicative Drainage Moderate
Structure High
Texture Loam
Indicative Permeability P (m/day) as Ksat 1.5-3.0

 

For our calculations we have assessed the design flow as follows

 

Design calculations

 

 

 

 

 

 

DIR (mm/day) (Advanced/Secondary quality effluent) 4.0
Hydraulic load (It/day/person) 120
Design flow Q (It/day) (equivalent population 7 people) 840
Design sizing calculation Ai=Q/DIR
= 840/4.0
Disposal Area Ai (m’) =210

 

 

 

 

Fixed Low pressure heavy droplet ‘wobbler’ type (or such) spray irrigation system

 

Note — AS/NZS 1547-2012 (Appendix H, Table H1) lists the typical wastewater design flow
allowance for households with an on-site roof water tank supply as 120litres/person/day (all
wastes). With the installation of standard water reduction fixtures the design flow can be
reduced substantially.

Where the design flow ‘Q’, nominated above, is exceeded the area (Ai) will need to be
increased accordingly. On-site sewerage systems are not suitable for accepting waste from
garbage grinders.

 

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4.0 FINDINGS

All the field information and test results collected during our site investigation and
detailed in this report, including any site plans, log and data sheets together form the
basis of our recommendations for this Land Application Facility.

The soil profile encountered during our investigations, and as reported, was
reasonably and acceptably consistent across the proposed development, and within
our expectations from regional experience and correlation with The Qld Dept of
Mines/Energy Geology Sheet 9445/1999 (Gympie), which describes the geology as
Late Triassic-Jurassic, Duckinwilla Group, Myrtle Creek Sandstone.

Our site investigation confirms the existing Land Application Facility incorporates a
Taylex treatment plant and moveable spray irrigation. Our site investigation confirms
the Land Application Facility has reached the end of its serviceable life, may have
failed, or is otherwise non-compliant, for one or a combination of the following
reasons;

e inadequate siting

e inadequate sizing

e inappropriate sprinkler placement and effluent distribution

e non-compliant pipework to and within disposal areas.

The proposed Land Application Area is on a partially exposed 3-5% southwestern
slope with neighbouring vegetation consisting of grasses and trees.

The landform was recorded as natural and partially disturbed.

Slope configuration across the proposed site is determined to be linear planar. Slope
stability problems were not evident during our investigations and expert evaluation
deemed unnecessary.

The susceptibility to flooding from groundwater is low and the indicative drainage
was recorded as moderate. No water table was encountered on the day of our site
investigation.

To comply with Queensland Plumbing Laws and Code it is now a requirement on
certain sites to be accompanied by a Sanitary Articulation Design (SAD). A SAD is
now required when the underlying soils of a site may be subject to excessive
settlement or surface movement due to a volumetric change of the soil caused by
changes in the ground moisture condition. The range of soil movement dictates the
Site classification and as such where it is expected some natural soil movement will
occur, articulated joints at key points on a drainage system is required. The
articulated joints are required to carry the differential movement between adjacent
structures (i.e. a house or retaining wall) and the natural ground around it in order to
prevent pipework from shearing and becoming displaced (potential spilling sewage
into the ground). On such sites a Sanitary Articulation Designs is now mandatory
across Queensland and requires a suitably qualified RPEQ Civil Engineer (or
Drainage Designer) to undertake the design.

 

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4.1 Limitations.

Our site and soil evaluation noted the following limitations which may have an
adverse effect on the performance, serviceability, and sustainability of
environmentally acceptable on-site domestic wastewater management

e allotment size, configuration and topographic idiosyncrasies,

e — separation distance requirements,

e areas previously used or required for construction or landscaping

In formulating our recommendations we have noted, considered and made allowance
for the effect these limitations will have on the performance, serviceability, and
sustainability of on-site domestic wastewater management. We consider that in line
with the recommendations set out within this report, and with appropriate control
measures in position, sustainable on-site domestic wastewater treatment and disposal
will be achieved.

In consideration of these limitations and with reference to the Queensland Plumbing
and Wastewater Code and AS/NZS1547-2012 On-site Domestic Wastewater
Management, we recommend advanced secondary treatment of all domestic
wastewater flows for the efficient, sustainable and environmentally acceptable
disposal of treated effluent on this allotment. The use of such approved systems
consequentially enables the 30m horizontal separation distance from the intermittent
watercourses/dams to be reduced to 10m, and the vertical separation distance to be
reduced to 300mm.

Although we recorded no existing evidence of eutrification, we believe there is the
potential for eutrification of any associated dam or watercourse if there is nutrient
leakage from any disposal site. However, with our recommended, and appropriate
vegetation planting, with the incorporation of a wastewater treatment system with
nutrient stripping capabilities and with the encouraged use of phosphate free cleaning
products, we believe the reduced potential will be contained.

 

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5.0 DESIGN RECOMMENDATIONS

We recommend the installation of a 10ep (min capacity) domestic wastewater
treatment plant to treat the domestic wastewater to an advanced secondary quality.

If the integrity and serviceability of the existing Taylex treatment plant is confirmed
we recommend its ongoing use with appropriate monitoring, maintenance and
servicing.

The treated effluent is to be pump-dosed into and along the fixed low pressure heavy
droplet spray irrigation system.

The number of spray outlets and type of spray outlet will be confirmed onsite prior to
or during commissioning of the facility and may require isolating or dosing valve
mechanisms.

This will help the Land Application Area receive treated effluent and residuals in a
manner and at a rate that enables their further treatment by natural in-soil stabilisation
processes so that the resulting clarified carriage water is environmentally and
hygienically acceptable for groundwater infiltration or evaporation and plant
transpiration into the atmosphere.

The final location of a new treatment plant will be determined on-site by variable
consequences (eg finished floor levels, distances, allotment configuration and
topographical constraints) over which we have little control. We recommend further
consultation to determine the adequacy of the final location of the treatment plant at
the time of, or prior to construction of the proposed dwelling.

Notwithstanding the final location of the treatment plant/tank and the Land
Application Area particular attention should be paid to protecting any, or all pipework
below driveways, access tracks, or such trafficable areas.

Our recommendations do not preclude other or additional Land Application Facilities.

Wastewater Treatment Systems and Land Application Facilities should be designed to
remove as much nitrogen as possible by ammonification, settlement in sludge,
denitrification, long residence times or plant uptake.

Water conservation implementation will reduce the hydraulic load on the Land
Application Facility and subsequently improve its performance and serviceable life.

Effluent quality from the treatment plant must comply with the criteria presented in
the Queensland Plumbing and Wastewater Code and AS/NZS 1547-2012 On-site
Domestic Wastewater Management and be confirmed with the regulatory authority.

Treated effluent shall be filtered before delivery to the Land Application Area. All
filters shall be checked and cleaned regularly, or as required.

 

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5.1 Installation Notes.

All installation works, components and fittings must comply with AS/NZS 1547—
2012 On-site Domestic Wastewater Management, and the Queensland Plumbing and
Wastewater Code, and the local authority.

Soils are susceptible to damage during the construction and installation processes.
The natural integrity of the existing soil conditions of the Land Application Area must
be preserved at all stages of the proposed development. Damage to the existing soil
profile must be avoided. Do not over work the soil profile. The system must not be
constructed or installed during or immediately after periods of wet weather.

Land Application Facilities and treatment systems/service plants (wastewater
treatment unit and disposal areas) must be located with good and clear access for
servicing and maintenance requirements.

All supply line excavations and trenching shall be backfilled with interceptors or
extended below the Land Application Area to inhibit surface water infiltration.

A reserve area shall be made available on-site for future use and is to be protected
from any development that would prevent its use in the future.

Particular care should be taken with the layout and construction of supply line
trenching/pipework, as with all drainage, plumbing and electrical trenches to inhibit
surface water infiltration along and into the Land Application Area. All supply line
excavations and trenching shall be backfilled with interceptors.

Particular care should also be taken with the layout and construction of the Land
Application Area trenching/pipework so that released effluent cannot travel back
along trenching causing excessive soil moisture in some areas.

Correct pipe layout and Land Application Area construction/installation is an essential
part of our recommendations and design. If the site is not prepared in accordance
with our design, or is prepared inadequately or is prepared poorly, inefficiencies may
occur and we do not take responsibility for the consequences in such cases and we
will make an additional charge if as a result, more testing, re-designing or re-writing
of the report is necessary.

 

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The treatment plant/ tanks traps and associated fittings shall be

e constructed of durable materials with expandable and/or flexible connections,

e positioned correctly in relation to boundaries, buildings to provide an angle of
repose of at least 45 degrees between the bottom of the footing system/excavation
and the base of any associated excavation

e watertight and capable of withstanding loads imposed on the roof and walls

e installed so that flotation will not occur in high watertable or when empty

e installed on a stable base and to prevent surface water infiltration

e located with clear access for servicing requirements and desludging operations

e located within a designated area to enhance its amenity

e protected from roof water/tank discharge, surface water flow and/or seepage

e installed and operated in accordance with manufacturers and regulatory guidelines

The supply lines to the wastewater treatment plant/tanks shall be adequately vented
with mosquito proof cowls fitted to all vents.

The Land Application Area shall

e not be located on land prone to water logging or subject to floodwater inundation
e be sited to be open to prevailing winds and not totally shaded from sunlight

¢ be protected from roof water discharge, surface water flow and/or seepage

e have no runoff or seepage of the applied effluent beyond the designated area

e be regularly inspected and maintained

e have the mandatory signage prominently displayed

e have boundaries clearly delineated/fenced to deter animals and pedestrian traffic

As the slope configuration was recorded to be linear planar the Land Application Area
shall be protected from surface water infiltration by the installation of an excavated
surface water diversion drain (suggested minimum 500mm wide and 150mm deep)
and from runoff by the installation of a vegetated track rolled retention
mound/transpiration buffer zone (suggested minimum 1000mm wide and 150mm
high).

In this instance the natural moderate drainagee characteristics of the consistent soil
profile, may be deemed to offer adequate protection from surface water infiltration.
Similarly, in this instance the existing endemic vegetation, extending downslope of
the proposed Land Application Area, may be deemed to be satisfactory as the
transpiration buffer zone.

It is essential that all associated stormwater flows from this and neighbouring
allotments, driveways, roads, tanks and roofs be diverted away and well clear of the
proposed Land Application Area.

Noosa Council may require an inspection for certification to be carried out before
final approval can be issued.

Unearthed Geotechnical P/L recommends an inspection for certification to be carried
out by the designer prior to commissioning, and preferably during construction, to
ensure code compliance and that ‘best practice’ principles have been utilised.

 

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5.2

Spray Irrigation (utilizing fixed outlets).

Spray Irrigation systems shall

be managed to ensure the even distribution of treated effluent across the
designated Land Application Area

have boundary delineation designed to deter grazing livestock, animals, vehicles
and casual access by humans

be constructed to prevent effluent ponding or run-off within or from the surface
of the land application area

allow no spray to reach areas normally occupied by humans or animals

control the droplet size, throw and plume height so that aerosol dispersion and
wind drift is negligible. The plume height shall not be more than 500mm above
the natural surface of the irrigation area and must not exceed 2m diameter

have a semi flexible robust system of pipes/fittings permanently buried and fixed
have sufficient spray fittings to distribute the applied effluent evenly and
efficiently (determined by the plume size). The number of, and hydraulics of the
final number of spray outlets may require the use of a indexing/dosing valve
mechanism

have pipes and fittings rated to withstand a minimum of 150% of the shut-off
head of the irrigation pump

ensure the effluent does not come into contact with people, domestic or farm
animals or any crops intended for human consumption

have pipes buried to a depth of at least 100mm and the irrigation system shall be
permanently installed

have warnings, complying with AS/NZS 1319, at the boundaries of the
designated area in at least two places, clearly visible to property users with
wording such as “Recycled Water — Avoid Contact DO NOT DRINK”

have the presence of the buried supply lines indicated using underground marking
tape (to AS/NZS 2648.1:1995) or appropriately marked purple striped pipe.

Polyethylene complying with AS/NZS 4130:2009 and AS/NZS 4129:2008 (Int), PVC Class 12
complying with AS/NZS 1477:2017 is suitable for the header and main pump pipework.
UPVC pipes and fittings and garden hoses and fittings are not suitable. Optimum
performance from drip irrigation systems is obtained using high quality secondary treated
effluent, or better, having BOD; and suspended solids of 20/20 g/m’ to 15/15 g/m’.

Pump Systems shall

have a separate effluent pump chamber/tank volume of at least 200It with an
additional emergency storage volume of 24 hours flow rate

match the electrical starting requirements of the irrigation pump motor

have performance characteristics that match the hydraulic characteristics of the
irrigation system

have a discharge of at least 50% greater than the maximum 30 minute flow rate
have a visual and audible alarm system (with muting ability) for breakdown
notification

not be located adjacent to bedrooms, living rooms or recreational areas of
neighbouring properties

be contained in an acoustic chamber to reduce noise emission of all equipment to
a level not exceeding 40 dB (measured as fast response at a distance of 1m).

 

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The system shall have the ability to isolate the effluent from the sprinkler system to
enable servicing and maintenance requirements of the irrigation area. The method of
isolation cannot cause harm to the treatment plant operation (pump, electrical,
treatment). Manufacturer of the treatment plant is to approve the method of isolation.
Spray outlets are not permitted to operate when persons are required to enter the Land
Application Area (e.g. when being serviced and/or maintained).

There are obvious increased public health risks associated with effluent spray
irrigation systems due to the potential contact with effluent by humans, animals and
insects.

5.3 Planting Regime.

Plantings improve the efficiency of the system with the uptake of nutrient and natural
transpiration processes. Further qualified advice from local nurserymen and the local
regulatory authority should be preferred when choosing plants that may be more or
less suitable or acceptable to your region. Grasses should be kept well mown and
raked for better evaporative and transpiration processes (avoid throwing grass
clippings onto the Land Application Area). Shrubs should be kept well pruned for
better evaporative and transpiration processes.

Endemic vegetation must be retained and/or reinstated.

Following the site preparation, installation and pre-commissioning tests the Land
Application Area shall be allowed to revegetate with sufficient appropriate shallow
rooting grasses or shrubs, as determined by historical performance outcomes.

Unearthed Geotechnical P/L recommends further assessment regarding planting
requirements be sought prior to, or at the time of installation of the Land Application
Facility. It may be necessary to implement an additional planting regime.

Do not plant shrubs or trees within the surface water diversion drains, as these drains
need to be kept free of obstruction and debris for maximum diversion efficiency.

We recommend the application of dolomite at a nominal rate (say, 0.25 kg/sqm)
when preparing the existing soil. This will assist with both plant growth and/or pH
control. Further applications will be required during the serviceable life of the Land
Application Area.

 

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5.4 Separation Distance Requirements.

One of the most important parameters to consider in the location of Land Application
Areas is the separation distances, both vertical and horizontal.
inappropriately selected ground may contribute to the pollution of surface water and

groundwater, ponding and eutrification.

Surface Horizontal Separation distance requirements

Poorly or

 

 

 

 

 

Feature Primary Secondary hod
Permanent watercourses (lake/stream/river) 50m 30m 10m
Intermittent watercourses (dams/channels/weirs) 50m 30m 10m
Bore (human and or domestic consumption) 50m 30m 10m
EMT boundary unlined/open stormwater drainage 50m 30m 10m

 

Property boundaries/paths/walkways

4m downslope 2 m upslope boundary

 

 

 

 

 

 

 

 

 

. 10 m spray 10 m spray

Dwellings/play areas 15m
4m sub/cvrd | 4m sub/evrd
Swimming pool (water edge) 6m 6m 6m
Inground watertank 15m 6m 6m
Vertical Separation distance requirements
: , Advanced

Depth of unsaturated soil to Primary | Secondary Sevoridary
Permanent watertable 12m 0.6m 0.3 m
Bedrock/hardpan 1.2m 0.6m 0.3m

 

 

 

 

5.5 Effluent Quality.

Effluent quality requirements must be confirmed with the relevant local council
before proceeding and when tested shall comply with the following;

 

 

 

 

 

 

 

 

Effluent Quality Primary | Secondary . sain
Biochemical Oxygen Demand (mg/It) 120-240 <20 <10
Total Suspended Solids (mg/It) 65-180 <30 <10
Total Nitrogen (mg/It) 36-45 <30

Total Phosphorous (mg/It) 6-10 <10

Thermotolerant Coliforms (organisms/100 mL) <200 <10

 

 

 

 

Unearthed Geotechnical P/L. 11

Design Report 023-038

 

 

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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).

 

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OPERATION AND MAINTENANCE GUIDELINES

General

The purpose of these guidelines is to provide guidance to homeowners and operators
on maintaining a Land Application Facility in an unsewered area. The focus of these
guidelines is the facilitation of sustainable on-site disposal of treated effluent without
compromising public health or the quality of the environment.

The amount of wastewater to be treated is a major design factor in wastewater
treatment systems. Exceeding the design flow will contribute to failure. Water
conservation will reduce the volume of effluent requiring disposal to the Land
Application Area, which will increase its serviceable life and improve its efficiency.

Conservation measures include

e employing careful water use habits,

e installing flow/pressure valves on all water outlets,

e having leaking taps repaired immediately,

e only using dish washers when there is a full load,

e avoiding overloading the system by spacing out water use as evenly as possible,
e installing reduced flush (6/3 litre preferred) water closets,

installing water conserving automatic washing machines, and

shower-flow restrictors and aerator faucets.

AS/NZS 1547-2012 (Appendix H, Table H1) lists the typical wastewater design flow
allowance for households with an on-site roof water tank supply as 120-
litres/person/day (all wastes). With the installation of standard water reduction
fixtures the design flow can be reduced substantially.

Efficient on-site sewerage treatment relies on a balanced combination of physical,
biological (bacterial) and chemical processes. In order to keep bacteria working
efficiently in the tank/plant and the Land Application Area

e restrict the amount of solid wastes entering the system,

e use biodegradable soaps, cleaning products with low phosphorus/ nitrogen levels,
e use low-phosphorus and low-sodium detergents,

e use detergents in recommended quantities,

e do not use powerful bleaches, whiteners, nappy soakers, spot removers, and

e do not put chemicals, disinfectants, oils or paint down the drain.

 

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Garbage grinders are not suitable for on-site domestic wastewater treatment plants as
their use introduces large amounts of additional solid matter, which must be broken
down by the system. Their use also greatly increases the hydraulic load.

All wastewater treatment plants/systems work less efficiently when overloaded with
solid wastes. All reasonable and necessary actions and efforts to restrict the flow of
solid wastes, particularly from the kitchen, shall be encouraged and employed by all
present and future owners/ occupiers/users of this Land Application Facility.

A baffled grease interceptor trap on the kitchen waste supply line is a valuable
addition to any wastewater treatment system. If installed/recommended this will, with
effective maintenance, limit the amount of grease, fats and other solid matter from the
kitchen that enters the Land Application Facility.

The choice of cleaning products will influence the environmental impact of
greywater and, equally, will influence the overall performance of treatment
within the treatment plant. Only genuine biodegradable products and products
with low phosphorus should be used. Common washing powders contain sodium
salts as bulking agents which produces a saline greywater. Powdered products
which use potassium salts or liquid concentrates produce better quality
greywater. Some detergents and powder cleansers contain boron which not only
can be toxic to plants in high concentrations but can also be toxic to animals.

Operation

This Land Application Facility shall be used only for effluent application and not used
for purposes that compromise the effectiveness of the system or access for future
maintenance purposes.

In order to reduce sludge build-up in the tank never dispose of used cooking oil
grease/fats or food scraps or similar material down the sink.

Do not allow newspapers, disposable or sanitary napkins, rubber products, nappy
liners, cotton buds etc. to enter the system. The use of better quality toilet paper can
also help in improving operation of the system.

Do not allow excessive quantities of disinfectant liquids, bactericides, antiseptics,
strong caustics, acids, alkalis or chemical detergents to enter the wastewater system.
Their use can severely affect the bacterial, biological and chemical processes within
the system. Minimise their use and use more environmentally friendly products.

Where possible, the owners/householders/users should avoid shock loading of the
system, for example, by staggering the hours that the washing machine is used, and
the peak times in the bathroom. Washing machines should be used where possible
throughout the week instead of several loads within one day.

 

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Maintenance

The grasses/shrubs used in conjunction with any Land Application Area should be
kept well mowed/pruned to ensure that these plantings take up nutrients with
maximum efficiency.

Grease interceptor traps if installed must be pumped out/cleaned periodically or as
necessary. The frequency of service is dependant on its use and on the build up of
greases and fats within the trap.

Septic tanks and or primary tanks/chambers for wastewater treatment plants reduce
solids by bacterial deposition. Consequently, sludge settles at the bottom of the tank
and a scum or crust forms at the liquid surface. Periodic checks are necessary (eg
annually depending on the load entering the system), to ensure that no carry-over of
solid matter is entering the Land Application Area. It may well be a number of years
before the sludge level rises to a level (when scum and sludge occupy 2/3rds the
volume of the tank or fist stage of a two-stage system), which is detrimental. This is
seldom less than three (3) years (depending on the load imposed on the system and the
size of the septic tank or primary tank/chamber). Under normal circumstances,
desludging of a septic tank should be performed every three to five (3-5) years. If
existing septic tanks are to be incorporated they shall be fitted with outlet filters, and
must also be pumped out before commissioning of the system. All manufacturer
maintenance/service requirements are to be met.

Filters

An effective filtration system for all wastewater treatment systems is essential. The
type required will depend on the type of system installed and the quality of the water
to be filtered. The size of the system will also determine which filter system would be
appropriate. In recent years, effluent filters have been added to the septic tank outlet
baffle to limit carry over of solids. All filters shall be cleaned at regular intervals (eg.
every six months or more often if and as necessary). Media, screen or disc filters can
be used depending on water quality. The filter shall be installed as far down the main
supply line as practical. This is an insurance policy, in case a break occurs in the
main line, or solids coagulate/form on the pipe walls and strip off in larger formations,
which may cause blockages.

 

Unearthed Geotechnical P/L. 15 Design Report 023-038

Page 17

Planting Regime

Plantings improve the efficiency of the system with the uptake of nutrient and natural
transpiration processes. Further qualified advice from local nurserymen and the local
regulatory authority should be preferred when choosing plants that may be more or
less suitable or acceptable to your region. Grasses should be kept well mown and
raked for better evaporative and transpiration processes (avoid throwing grass
clippings onto the Land Application Area). Shrubs should be kept well pruned for
better evaporative and transpiration processes.

Endemic vegetation must be retained and/or reinstated.

The Land Application Area shall remain vegetated with sufficient appropriate shallow
rooting grasses or shrubs, and the retention mounds/transpiration buffer zones, if
required, shall remain vegetated with sufficient appropriate shallow rooting grasses,
shrubs or small trees as determined by historical performance outcomes.

Unearthed Geotechnical P/L recommends further assessment regarding planting
requirements be sought prior to, or at the time of installation of the Land Application
Facility. It may be necessary to implement an additional planting regime.

Do not plant shrubs or trees within the surface water diversion drains, as these drains
need to be kept free of obstruction and debris for maximum diversion efficiency.

We recommend the occasional application of dolomite/gypsum at a nominal rate to
the Land Application Area. This will assist with both plant growth and/or pH control.

 

Unearthed Geotechnical P/L. 16 Design Report 023-038

Page 18

Greywater Characteristics

The definition of greywater in the AS/NZS 1547:2012 Onsite Domestic-wastewater
Management is: “The domestic wastes from a bath, shower, basin, laundry and
kitchen but excluding toilet and urinal waste”.

The characteristics of greywater generated by a household will vary also according to

the dynamics of the household and is again influenced by the number of occupants,

the age distribution of the occupants, their lifestyle characteristics and water usage
patterns. Wastewater may have become contaminated in three ways

e by microorganisms, many of which may be pathogenic, i.e. cause disease;

e chemically by dissolved salts such as sodium, nitrogen, phosphates and chloride
or by organic chemicals such as oils, fats, milk, soap and detergents which may
provide food for micro-organisms and plant growth; and

e physically polluted by particles of dirt, food, lint and sand etc.

Greywater contains many impurities, including nutrients such as nitrogen and
phosphorus, which may harm the environment and the soil in particular. There are
some chemicals, which are not capable of being treated or degraded in the soil.
Therefore the soil ecosystem must be capable of adsorbing, absorbing, assimilating or
treating the chemical impurities and nutrients without medium and long-term
degradation of the soil of the environment. Domestic greywater treatment systems are
designed primarily to treat organic matter and are not normally designed to remove
chemical salts such as sodium, nitrates and phosphates that may be found in
greywater.

If a member of the house is ill or is carrying a subclinical infection, greywater may
carry infectious bacteria or viruses. However, in order for the greywater to make
another person ill it would be necessary for that person to drink or otherwise consume
the contaminated greywater inhale aerosols, touch or consume items, which have
come in contact with contaminated water. The objectives of the standards are to avoid
human contact with greywater. When greywater is being used follow these rules:

e don’t drink or play in greywater.

e don’t allow anything that may be eaten to come in contact with greywater.

e don’t allow greywater to pond on the surface or run off the property.

e don’t wash domestic pets in greywater or allow these pets to drink the greywater.

e wash your hands after contacting greywater or otherwise dealing with greywater.

Storage of Greywater

All forms of wastewater when stored will turn septic unless the wastewater is treated
to a high standard. Similarly, when greywater is stored it will also turn septic giving
rise to offensive odours and provide conditions for microorganisms to multiply.
Significant levels of pathogens have been found in stored greywater after eight days.
Should the stored septic greywater be surface irrigated it will give rise to extremely
offensive odours, provide conditions conducive to disease transmission and attract
insect and rodent vectors. Greywater must not be stored, other than temporarily,
unless adequately treated.

 

Unearthed Geotechnical P/L. 17 Design Report 023-038

Page 19

Presence of Pathogenic Microorganisms

Greywater may be contaminated with microorganisms such as bacteria, viruses and
protozoa. It is these microorganisms, many of which may cause disease, that present
the greatest health concern associated with greywater recycling and disposal. While
many bacteria cannot survive in a hostile environment like soil, some bacteria and
viruses that cause disease are resilient and can often survive for long periods of time
in this environment. Disease transmission is principally through the faecal-oral route
where the greywater may be directly ingested through contaminated hands or
indirectly ingested through contact with contaminated items such as grass, soil, toys,
garden implements and treatment plants while they are being serviced. Transmission
may also occur through inhalation of irrigated spray, by penetration through broken
skin, and by insect vectors such as flies and cockroaches. Contaminated drinking
water aquifers may facilitate ingestion of pathogens.

Comparison with Raw Sewage and Blackwater

Raw sewage, blackwater and septic tank effluent are all forms of effluent that are
directly and grossly contaminated with human excrement and therefore represent a
public health threat. Sewage, blackwater and septic tank effluent are all managed by a
high level treatment before being released into the environment above ground level
and must at least be settled or filtered to remove solid particles before management by
sub-soil land application area. Raw sewage is usually directed, in metropolitan and
urban areas, to a centralised sewage treatment plant for treatment and utilisation or
disposal. Septic tank effluent is sewage that has been stored in a large vessel or tank
and has turned septic, i.e. all the oxygen in solution has been consumed by the
decaying process and the septic tank effluent becomes offensively smelly.

Laundry Greywater

Microbiological: variable thermotolerant coliform loads, depending on dwelling
occupancy i.e. family with children. Wash water has poorer microbial quality than
rinse water.

Chemical: sodium, phosphate, boron, surfactants, ammonia and nitrogen from soap
powders and soiled clothes.

Physical: high in suspended solids, lint and turbidity.

Biological: high in biochemical oxygen demand,

Laundry wastewater represents about 23% of household wastewater (35% of
greywater). The detergents used in clothes washing give rise to the presence of
phosphorus, ammonia, organic nitrogen and boron in varying amounts depending on
the product and suspended solids such as lint, hair and dirt. Many of these
contaminants are classified as nutrients and if transferred to waterways or
groundwater may lead to environmental damage.

 

Unearthed Geotechnical P/L. 18 Design Report 023-038

Page 20

Bathroom Greywater

Microbiological: variable levels of thermotolerant coliform, poorer microbial quality
than laundry rinse water.

Chemical: soap, shampoo, hair dyes, toothpaste and cleaning chemicals.

Physical: high in suspended solids, hair and turbidity.

Biological: lower levels of concentrations of biochemical oxygen demand.

The bathroom (hand basin, shower and bath) generates about 38% of the household
wastewater flow (55% of greywater) and is considered to be the least contaminated
type of greywater. Wastewater from hand basins is more polluted than bath or shower
wastewater. Soap is the most common chemical contaminant found in bathroom
greywater and other common contaminants are hair shampoo, hair dyes, toothpastes
and cleaning chemicals. Biocidal soaps have little effect on reducing the bacterial
load in greywater.

Kitchen Greywater

Microbiological: variable thermotolerant coliform loads.

Chemical: detergents, cleaning agents.

Physical: food particles, oils, fats, grease turbidity.

Biological: high in biochemical oxygen demand.

Kitchen wastewater is heavily polluted physically with food particles, oils, fats and
other highly polluting waste and is often more polluted than blackwater or raw
sewerage. It readily promotes and supports the growth of microorganisms. Because
of the solid food particles and because fats can solidify, kitchen wastewater may cause
blockages in land application systems unless fats are treated or removed from
greywater.

Swimming Pool and Spa Pool Backwash Water

Swimming pool backwash water is highly concentrated in microorganisms, chemicals
(such as body oils and cosmetics) and particulates such as powder residue, hair, lint
and pool chemical residues. The amount of backwash water is difficult to estimate
and is variable depending on the size of the pool, filter type and usage patterns.

 

Unearthed Geotechnical P/L. 19 Design Report 023-038

Page 21

 

INFECTIOUS AGENTS PRESENT IN RAW DOMESTIC WASTEWATER

 

 

 

 

 

 

 

 

 

 

 

 

 

Organism Disease | Remarks
Bacteria
Escherichia coli Gastroenteritis Diarrhoea
(enteropathogenic)
Legionella pneumophila Legionellosis Acute respiratory illness
Leptospira (150 spp.) Leptospirosis Jaundice and fever
(Weil’s disease)
Salmonella typhi Typhoid fever High fever, diarrhoea and
ulceration of small intestine
Salmonella (~1700 spp.) Salmonellosis Food poisoning
Shigella (4 spp.) Shigellosis Bacillary dysentery
Vibrio cholerae Cholera Extremely heavy diarrhoea
and dehydration
Yersinia enterolitica Yersinosis Diarrhoea
Viruses
Adenovirus (31 types) Respiratory disease

 

Enteroviruses (67 types eg.
Polio, echo and Coxsackie
viruses)

Gastroenteritis, heart
anomalies and meningitis

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Hepatitis A Infectious hepatitis Jaundice and fever
Norwalk agent Gastroenteritis Vomiting
Reovirus Gastroenteritis
Rotavirus Gastroenteritis
Protozoa
Balantidium coli Balantidiasis Diarrhoea and dysentery
Cryptosporidium Cryptosporidiosis Diarrhoea
Entamoeba histolytica Amebiasis (amoebic Prolonged diarrhoea with
dysentery) bleeding and abscesses of the
liver and small intestine
Giardia Lamblia Giardiasis Mild to sever diarrhoea,
nausea and indigestion
Helminths
Ascaris lumbricoides Ascariasis Roundworm infestation
Enterobius vericularis Enterobiasis Pinworm
Fasciola hepatica Fascioliasis Sheep liver fluke
Hymenolepis nana Hymenolepiasis Dwarf tapeworm
Taenia saginata Taeniasis Beef tapeworm
Taenia solium Taeniasis Pork tapeworm
Trichuris trichiura Trichuriasis Whipworm
Source: Metcalf and Eddy, Inc., 1991.
Unearthed Geotechnical P/L. 20 Design Report 023-038

 

Page 22

Conclusion

A failed Land Application Facility is both a serious public health risk and an
environmental hazard that can lead to

the spread of infectious diseases,

breeding mosquitoes and attraction of flies and rodents,
nuisance and unpleasantness,

pollution and infection of waterways,

contamination of bores, wells and groundwater,
alteration of the local ecology,

fish kills, and

legal action.

Problems can occur with systems that have not been adequately maintained. Some
early warning signs are very obvious

the disposal area is wet and/ or soggy with effluent ponding on the surface,
there is a smell of “sewerage” near the septic tank or absorption area,

the drains and toilets run slowly,

the grease trap is full or blocked,

mechanical failure, and

excessive running costs.

Home owner/occupiers/users are legally responsible to keep their on-site wastewater
treatment system in good working order. If any warning signs are evident the home
owner/occupier/user must contact the nearest local authority office without delay.

A full copy of this report and all the accompanying sketches plans details and notes shall be
made available to all present and future owners and or occupiers of the house and shed that
are serviced by this Land Application Facility.

 

Unearthed Geotechnical P/L. 21 Design Report 023-038

Page 23

 

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Page 24

 

    

PROPOSED
HOUSE SITE

   
   

 
 

EXISTING
STABLES EXISTING

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PROPOSED LAND x
APPLICATION AREA aN
\ oN

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COOROY Noosa ROAD

   

    

50 : 0 50 100 150 M ¢| /S

SCALE | : 2500
\\synology\General\WJOBS\Jobs-023-00\023-000s\023-038-Coveys\023-038-Drawings.dwg

3/03/2025 Unearven GEDTECHMCAL Ano SHALL HOT BC COMED

 

CLIENT: CHRIS FLEMING (0438 370 247)

 

 

 

LoT 12 SPI59169 (71) CovEYs Rob, ———
ORIG. SHEET SIZE: A&
TINBEERWAH. _ NOOSACOUNCIL. SCALE: 12500

 

UNEARTHED GEOTECHNICAL P/L
A.J. TRELOAR QBCC Lic, No.740251 PO Box 1204, GYMPIE, QLD 4570 O4I7 152 300 [email protected] PLAN No. 025-058A

 

 

 

 

 

Page 25

 

 

7
7
7 PROPOSED
HOUSE SITE /

N/
7
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/

..
PROPOSED LAND APPLICATION DESIGN \
& RESERVE AREA (>400sam)

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COOROY Noosa ROAD

30M

10 0 10 20

ot

SCALE | : 500

  

\\synology\General\JOBS\Jobs-023-00\023-000s\023-038-Coveys\023-038-Drawings.dwg|

|

 

CLIENT: CHRIS FLEMING (0438 370 247) 5/03/2023

 

Lot I2 SPI39169 (71) CovEYsS RoaD,
TINBEERWAH. NOOSACOUNCIL.

COPYRIGHT: THESE PLANS ARE THE PROPERTY OF
UNEARTHED GEOTECHNICAL AND SHALL NOT BE COPIED
‘OR REPRODUCED WITHOUT THE APPROVAL OF
UNEARTHED GEOTECHNICAL.

 

ORIG. SHEET SIZE: A&

 

 

UNEARTHED GEOTECHNICAL P/L

SCALE: 1:500

 

 

A.J. TRELOAR QBCC Lic. No.74025|__PO Box 1204, GYMPIE, QLD 4570 0417 132 300 [email protected]. AU

PLAN No, 023-0584

 

 

Page 26

 

     

PROPOSED LAND APPLICATION
DESIGN AREA (42X5M=210SQM)

 

Sa MMS VeAviLy VEGETATED cnouNo

Z\OOMM ORGANIC MULCH (EXISTING/NATURALLY REPLENISHED)
"EXISTING GROUND LEVEL

ADD DOLOMITE/GYPSUM. PRESERVE EXISTING SOIL INTEGRITY. Do NOT OVERWORK
THE SOIL OR CONSTRUCT DURING OR JUST AFTER PERIODS OF WET WEATHER.

\\eynology\General\JOBS \Jobs-023-001023-000e1023-038-Coveysi023.038-Drawings. dwg}

 

CLIENT: CHRIS FLEMING (04358 370 247) 5/03/2025 UveanTie GEDTECHNCAL AND EMAL NOT BE COPED

 

 

Lot 12 SPI39169 (71) CoveEYs Roab, —
TINBEERWAH. NOOSACOUNCIL.

 

 

 

ORIG. SHEET SIZE: A&
SCALE: NTS
UNEARTHED GEOTECHNICAL P/L 023-038
A.J. TRELOAR QBCC Lic. No.740251 PO Box 1204, GYMPIE, QLD 4570 O4I7 132 300 [email protected]| PLAN NO. ~0O8A

 

 

 

 

Page 27

 

 

LEGEND

seetteees APPROXIMATE LIMIT OF 20M SEPARATION DISTANCE FROM THE SHED & IOM FROM THE BORE

ad FIXED LOW PRESSURE HEAVY DROPLET OUTLETS, PLUME HEIGHT 500MM MAX & 2M DIAMETER MAX

' | EXPECTED LAND APPLICATION DESIGN & RESERVE AREA

ADVANCED SECONDARY TREATMENT PLANT (HSTP, IOEP FINAL LOCATION TO BE DETERMINED ON SITE), EXISTING HSTP

Ww) INDEXING/DOSING VALVE (IF REQUIRED)

BHI
oe BOREHOLE LOCATION AND NUMBER

ALL OVERLAND FLOW, STORMWATER AND DRAINAGE IS TO BE CONTROLLED
VARIOUSLY AND DIRECTED AROUND AND CLEAR OF LAND APPLICATION AREAS

THE NUMBER, TYPE AND LOCATION OF SPRAY OUTLETS TO BE
DETERMINED AND CONFIRMED PRIOR TO OR AT TIME OF COMMISSIONING
OF THE FACILITY AND MAY VARY FROM THIS NOMINATED PLACEMENT

\\synology\General\JOBS\Jobs-023-00\023-000s\023-038-Coveys\023-038-Drawings.dwg}

 

 

 

 

 

 

 

 

CLIENT: CHRIS FLEMING (0438 370 247) 3/03/2023 thea ene se cre
Lot 12 SPI39169 (71) CovEYs Roap, feu, Ser Sees Bo
TINBEERWAH. _ NOOSACOUNCIL. SCALE: NTS
UNEARTHED GEOTECHNICAL P/L
A.J. TRELOAR_QBCC Lic, No.740251 PO Box 1204, GYMPIE, QLD 4570 O4I7 132 500 [email protected]| PLAN No. 025-058A