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Waste Treatment and Assimilation

The extent to which ecosystems are able to transport, store and recycle certain excesses of organic and inorganic wastes through distribution, assimilation, transport and chemical recomposition.


Regulating Functions

How does waste treatment and assimilation contribute to ecosystem service provision?

The ebb and flow of tides transports, distributes and assimilates wastes.

Vegetation can strip excess nutrients and wastes from the water column, however if systems are overloaded with wastes their ability is impaired.

Waste is an unwanted or useless material and, in natural ecosystems, there is no such thing as waste because all materials are utilised, cycled and recycled. One organism’s waste is another’s resource.  For example leaf litter on a forest floor is decomposed (e.g. by fungi and soil biota) and the nutrients made available for new growth. Animal feces are similarly sources of nutrients.

Waste treatment and assimilation plays a critical role in buffering the impacts of high nutrients and other pollutants generated by human activities. The relative magnitude waste treatment and assimilation contributes to different ecosystem services (relative to other ecosystem functions) in SEQ is presented in Table 1. From a water quality perspective, when we add too much nutrient to a system, such as through nutrient rich wastewater releases or runoff from adjacent ecosystems into waterways – the system can become out of balance and fuel the growth of nuisance species like algae, bacteria and aquatic weeds. Pathogens in untreated waste can lead to significant human and environmental health issues. Hence, waste treatment plays a significant role in regulating pests and disease.

The waste treatment and assimilation function is also apparent in the way pollution incidents, such as oil spills, can be managed by ecosystems. The flow of water, for example through tidal and wave action can transport and distribute some excesses of nutrients, diluting and assimilating wastes, or transporting them to more or less sensitive areas. Carbon dioxide (CO2), a gaseous waste, is assimilated by vegetation and the chemical compound recompositioned (e.g. plants absorb carbon and release oxygen (O2)).

Waste treatment contributes significantly to many of our cultural services. Maintaining the capacity of ecosystems to perform waste treatment is important to protecting iconic species and landscapes. The treatment of wastes is important to providing the smell, sound and visual appearance of ecosystems that is required for people to experience aesthetic amenity. What therapy can be received from polluted landscapes? As well, access to and potential use of ecosystems can be denied by authorities should they be considered a health hazard to people. So waste treatment also contributes to food production and recreational opportunities (e.g. the potential to catch and eat fish) and maintaining healthy social relations (e.g. conflicts between polluters and service users).



What is the temporal and geographic scale waste treatment and assimlation operates at and services are delivered?

The flow of waste treatment and assimilation depends on state of the waste (e.g. gas, liquid or solid) and the medium in which the waste is transported (e.g. soil, water or air). If atmospheric pollutants are being assimilated, the flow is omni-directional; wind transport would be one-dimensional (landscape); transport in waterways is typically one-dimensional (downslope); or chemical recomposition can occur directly through soils (in-situ). It is important to remember however, that although many ecosystems are important to performing this function, there are limitations to this function and crossing treatment thresholds (which are still relatively unknown) can surpass the ability of ecosystems to perform this function and cause permanent degradation and transformation. The map to the right shows areas where the function waste treatment and assimlation is expected to occur across SEQ. Data sets supporting the map can be found in the Quick Index. By clicking on the link below the map it will provide a more detailed view.


How do we know if we are degrading, maintaining or improving waste treatment and assimilation in SEQ?


Links to other publications and websites

Healthy Waterways

In SEQ, the annual Report Card on aquatic ecosystem health provides an invaluable snapshot of the waste transport and assimilation function of our waterways and helps us identify short-term fluctuations as well as longer-term trends and processes. In SEQ there are some targeted local monitoring activities (such as air quality monitoring around landfills and major industry), but SEQ lacks a systematic approach to understanding waste treatment and assimilation functions across our productive landscapes and in relation to atmospheric pollution.


How do we manage this ecosystem function in SEQ?

Waste treatment and assimilation is managed using the waste management hierarchy: avoid, reduce, reuse, recycle and, as a last resort, offset.  There is growing momentum for the use of market based mechanisms such as pollutant trading schemes to create a more flexible regulatory environment and achieve outcomes at the least community cost. The Environmental Protection Act 1994 is the principal legislation for regulating waste treatment and assimilation and provides specific provisions for the licensing of waste discharges from Environmentally Relevant Activities (ERAs) such as industry and waste water treatment plants. Under the pervious government there was a waste levy that was intended to divert construction and building waste to landfill and this is to be discontinued, The management of this function is the responsibility of the Department of Heritage and Protection.