Septic absorption trenches: are they sustainable? Why are septic systems 'on the nose' in Australia? (original) (raw)

AUSTRALIAN ON-SITE WASTEWATER STRATEGIES: A CASE STUDY OF SCOTLAND ISLAND, SYDNEY, NSW AUSTRALIA

2000

Australian urban centres are primarily situated along wetter and more humid coastal areas, with much of the dry continental parts of the country remaining relatively undeveloped. Approximately 12 % of the population, in excess of 2 million persons, are not serviced by reticulated sewerage facilities and rely solely on on-site management for the treatment and disposal of domestic wastewaters. A

A Review of On-Site Wastewater Practices in South-East Queensland

This paper presents results from a 'census' of the status of on-site wastewater treatment systems (OWTS) management practices in the SEQ region as part of the Healthy Waterways initiative. The current number of on-site systems is estimated to be 127,000 with septic systems accounting for 80%. Key management issues were highlighted during the project, notably the frequency of greywater failure and inappropriate greywater discharge. Septic system failures were reported mainly in the newer combined septic systems that receive 100% of household water compared with the split blackwater systems that receive about 20%. Aerated systems were inadequately maintained. However, to date, no "smoking guns" of poor water quality from non-sewered catchments have been clearly identified. A clear outcome of this survey was the need for all SEQ Local Authorities to audit every on-site system. Predictions and assessment of catchment water quality risks from on-site systems would be gr...

Sustainable sewerage servicing options for peri-urban areas with failing septic systems

2010

The provision of water and wastewater services to peri-urban areas faces very different challenges to providing services to cities. Sustainable solutions for such areas are increasingly being sought, in order to solve the environmental and health risks posed by failing septic systems. These solutions should have the capability to reduce potable water demand, provide fit for purpose reuse options, and minimise impacts on the local and global environment. A methodology for the selection of sustainable sewerage servicing systems and technologies is presented in this paper. This paper describes the outcomes of applying this methodology to a case study in rural community near Melbourne, Australia, and describes the economic and environmental implications of various sewerage servicing options. Applying this methodology has found that it is possible to deliver environmental improvements at a lower community cost, by choosing servicing configurations not historically used by urban water utilities. The selected solution is currently being implemented, with the aim being to generate further transferable learnings for the water industry.

Are On-Site Systems Environmentally Sustainable?

Septic systems have a mixed reputation both with the Australian public and regulatory authorities. There is a general belief that they are an outdated and substandard means of on-site wastewater treatment. In this paper we explore the evidence for the sustainability of on-site systems using contamination of surface and groundwaters as primary criteria. Overall we show that despite consistent reports of a high (e.g. ≥20%) incidence of failing septic trenches, evidence for off-site impacts ranges from sparse to ambiguous at best. To help fill in experimental data gaps we discuss modelling results reported by both ourselves and others, that place contaminant exports (in particular N, P and faecal coliforms) in the context of likely export loads from existing land uses and increasing urbanisation.

Systemic barriers to wastewater reuse in Australia: some jurisdictional examples

Australasian Journal of Environmental Management, 2014

This article describes the regulatory framework and assessment process of urban wastewater reuse in two distinct regions of Australia, the Tamar Valley in northern Tasmania and the Hunter region of New South Wales. Relative similarities are evident between human population, water availability and recent necessity for reuse feasibility assessments. In the Hunter, assessments informed a state government led catchmentscale water security strategy. In Launceston, the need for assessments stems from a condition of the environmental permits for individual facilities. Salient institutional, social, economic and political barriers mire the assessment process for, and success of, wastewater reuse. Distinct legal, policy and procedural differences exist between the two cases. Future reuse guidelines should identify the different drivers for wastewater reuse and avoid studies that meet administratively predetermined selection.

Onsite Waste Water Treatment System

Onsite wastewater treatment systems (OWTSs) have evolved from the pit privies used widely throughout history to installations capable of producing a disinfected effluent that is fit for human consumption. Although achieving such a level of effluent quality is seldom necessary, the ability of onsite systems to remove settles able solids, floatable grease and scum, nutrients, and pathogens. From wastewater discharges defines their importance in protecting human health and environmental resources. In the modern era, the typical onsite system has consisted primarily of a septic tank and a soil absorption field, also known as a subsurface wastewater infiltration system, or SWIS. In this manual, such systems are referred to as conventional systems. Septic tanks remove most settle able and floatable material and function as an anaerobic bioreactor that promotes partial digestion of retained organic matter. Septic tank effluent, which contains significant concentrations of pathogens and nutrients, has traditionally been discharged to soil, sand, or other media absorption fields (SWISs) for further treatment through biological processes, adsorption, filtration, and infiltration into underlying soils. Conventional systems work well if they are installed in areas with appropriate soils and hydraulic capacities; designed to treat the incoming waste load to meet public health, ground water, and surface water performance standards; installed properly; and maintained to ensure long-term performance. These criteria, however, are often not met. Only about one-third of the land area in the United States has soils suited for conventional subsurface soil absorption fields. System densities in some areas exceed the capacity of even suitable soils to assimilate wastewater flows and retain and transform their contaminants. In addition, many systems are located too close to ground water or surface waters and others, particularly in rural areas with newly installed public water lines, are not designed to handle increasing wastewater flows.

Audit of septic tank performance

2001

The paper discusses a research project on septic tank treatment performance and an evaluation of factors that influence performance. Outcomes derived lay the groundwork for improved regulatory strategies for on-site domestic sewage treatment in Queensland's Logan City Council area. Key factors, which influence system performance, such as effluent quality, householder maintenance practices and site characteristics, were evaluated during the study. This research is expected to contribute to providing a rational basis for strengthening regulatory strategies governing on-site sewage treatment and furnish a specific focus for undertaking public information strategies relating to septic tank operation and maintenance.

The Crisis in U.S. Wastewater Infrastructure

The deteriorating wastewater systems in the U.S. have eluded public attention long past the point of becoming a critical threat to the country’s infrastructure. For too long citizens have taken for granted the everyday services provided by municipal sewers while such systems have strained under the demands of urban growth. Some of the sewer systems in this nation are over a century old, and have never been upgraded to accommodate for modern use. The detrimental effects of this widespread degradation are becoming increasingly prevalent. This paper will review the history of the American sewer system, its regulation, the current crisis, and the various methods of resolving it. Such information will be invaluable to anyone seeking to address this issue.

ON-SITE DOMESTIC WASTEWATER TREATMENT AND REUSE

This note includes descriptions of the different systems used for the on-site treatment and disposal/reuse of domestic wastewaters from residential developments in non-sewered areas in Australia. It also examines greywater treatment and reuse, which may be relevant in sewered areas. A number of well-known and emerging small-scale options are discussed, as well as the site and soil assessment requirements and land capability considerations which are required in the process of selecting and sizing an appropriate system. Aspects of the design, performance, and maintenance requirements of each of the systems are also described in this note.