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When a property lacks reticulated sewer services, it is an important piece of infrastructure that is not in place. In these circumstances, an on-site effluent management system is required which comprises two components. These are the treatment device or system and land application area (LAA) for the treated wastewater which have a considerable bearing on neighbouring lands, public health and the environment in regards to native vegetation, surface and groundwater quality for example. It is a very important decision to make because it is something people have to live with and manage, whilst the operation of an effluent management system also affects amenity and property values. This is where a Wastewater Consultant comes into play.

In simple terms, a Wastewater Consultant offers advice to landholders regarding the choice of effluent management system, needing considerable experience and expertise with treatment options and arrangements for land application. Effluent management reports are prepared by a Consultant for submission to Local Councils for approval, be it for the construction of dwellings, the renovation and extension of dwellings, a range of commercial scale developments and subdivision. An on-site effluent management system cannot be installed without Council approval.

A Wastewater Consultant should offer independent advice regarding effluent management options and not be financially affiliated with a particular supplier of effluent treatment systems. However, if a Client has a preference for a given type of effluent treatment system, a Consultant can try to work in with this. But the options for land application are often limited by the physical characteristics and constraints on a given property and the nature of the soil types and depth.

There is an Australian/New Zealand Standard and stringent guidelines in documents pertaining to the treatment and land application of effluent. Nonetheless, there are quite different approaches to on-site effluent management in different Council areas, who also often have their own specific policy’s and development control plans.

The role of a Wastewater Consultant and associated considerations are outlined below:

  1. Meet on the property with the owner and/or owner representative to ultimately prepare a report for on-site effluent management.
  2. Such meetings allows the Consultant to get a feel for the nature of a given development, estimate the maximum design effluent volume and outline the range of potential options available for effluent management so owners can make fully informed decisions in this regard before committing to what is outlined in a report. Often, quite obscure factors come into play for owners making the choice of effluent management treatment and land application system. This can only be identified if a Wastewater Consultant offers the time to discuss things in detail with Clients, as well as asking and answering a range of pertinent questions. 
  3. Convey to Clients the relevant matters to consider with effluent treatment systems which include the treatment levels that controls land application options as well as environmental and public health parameters, mechanical versus passive treatment and land application options, the nature of the power supply, an indication of initial costs and on-going operational and management requirements and costs. 
  4. For dwellings, a LAA for treated wastewater must be sized on the basis of the maximum potential occupancy level of a given dwelling which is determined by the nature of the water supply be it reticulated town water or tank water from roof runoff, as well as the number of bedrooms and potential bedrooms such as studies or offices for example.
  5. Carry out a detailed site and soils assessment after meeting with Clients on properties to determine the method of land application for treated wastewater and size and location of such an area. There are many controls in this regard and a LAA also has to fit with the intended usage of a landholder, whereby recreational usage, vehicular movements and hoofed animals should be avoided. In addition, appropriate clearance is required from features of development, property boundaries and ‘water features’ such as dams, intermittent watercourses and perennial watercourses. Slope, vegetation and aspect also come into play when siting a LAA for treated wastewater.
  6. Soils in a given LAA are normally assessed by boring hand-auger holes ideally to a depth of 1.2m or more where possible. Depth to bedrock is also an important consideration, particularly if at a shallow depth. The soil types, structure and overall depth have a substantial direct bearing on the options available for the land application of treated effluent. Assessment of soil types and structure is a specialised science in itself, whereby parameters are related to LAA options and sizings. In an ideal world, a variety of land application options are available, but experience shows this is commonly not the case.
  7. After the Client liaison and site and soils assessment, the Wastewater Consultant is in a position to prepare an effluent management report. Note that such a report is referred to in a few different ways in different Council areas, but all relate to on-site effluent management. The report should outline the nature of the development, specific choice of effluent management system, the maximum design effluent volume, pertinent site and soils characteristics, location of a LAA, calculations in relation to the sizing of the LAA and management and operational guidelines. The components of an effluent management system should also be shown on a site plan that is submitted in conjunction with a report.    
  8. A single arrangement for effluent treatment and land application should be put forward in an effluent management report for dwellings and commercial scale developments. A range of options should not be included in a report as the Local Council will either decide what they prefer, thereby taking this decision away from owners, or not actually approve things in the first place because nothing has been specified. It is the Wastewater Consultants role to make these decisions in close association with Clients by offering enough details and doing an appropriate site and soils assessment. 
  9. For subdivisions, building envelopes for the siting of future dwellings and effluent management areas for the land application of treated effluent are delineated. A variety of options can be considered for effluent treatment, pending final confirmation by future owners. Where possible, a variety of options are also available for the land application of treated effluent in subdivisions, but this is not always possible.
  10. It is most important to fully support Clients beyond the point of report preparation to obtain the approval if any queries are raised by a Local Council.
  11. Support Clients beyond the point that Council approval is gained if required.   

In some instances, a limited number of Councils offer guidelines that may not facilitate the need for an effluent management report by a Wastewater Consultant. However, such a process is to be undertaken by owners, whilst guidelines typically do not relate to all potential options available for effluent management, often being generalised, confusing and technically incorrect. This leaves the onus on owners to take the lead with an assessment and provision of details including soil types, structure and depth and locating LAA’s based on the variety of factors that have to be adhered to. In such circumstances, an effluent management report can still be submitted to Councils for approval which is a benefit to owners because they have an independent Wastewater Consultant to steer them through the process and offer the advice required to make the important decisions regarding effluent treatment and land application. It is best to get things done professionally to obtain the best outcome for effluent management and not install a system that may not operate properly and be prone to failure. This is because owners have to live with the effluent management system and it is expensive to upgrade or replace a system if not designed and installed properly.     

By Grant Austin, Engineering Geologist and founder of Blue Mountains Geological & Environmental Services Pty Ltd who has been specialising as an independent Consultant in the field of on-site effluent management since 1991 and assessed approximately 2700 sites (by August 2017) in over 50 different Council areas in NSW. Phone 4782-5981 and 0434-271-813. Email bmges@spin.net.au

Disclaimer: This submission has been prepared to assist members of the public to understand, define and explain the role of a Wastewater Consultant and how they should operate. Importantly, this must be in an independent manner and a Wastewater Consultant must not be formally affiliated with a particular wastewater treatment company in a commercial sense. The details provided are an informative direction to the public.