Recently I have been approached by a group of concerned constituents, regarding the proposed development of a composting facility in St Leonards.
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This composting facility will be taking biosolids from the nearby sewage treatment plants and converting it into useable compost for use in agriculture.
This got me thinking that I knew nothing about these facilities that are located in three other areas in Tasmania or the processes they use to keep biosolids from being disposed of by burying. Biosolids are a byproduct of sewage treatment plants. They are derived from the leftover solid material that remains after the removal of contaminants (such as plastics and sanitary items) and most of the liquid product.
Biosolids are treated to reduce odour and pathogen levels and tested to check compliance, before leaving the treatment plant. Biosolids are a plentiful source of nutrients that will never run out.
The application of biosolids to land is a known and accepted practise (in place for 25 years), that enriches the nutrients in the soil through a more natural product than using synthetic fertilizer. They also increase soil carbon, as well as the soil's water-holding capacity. Most biosolids contain nitrogen. phosphorus, and organic matter, and some contain lime, which can assist in maintaining productive soils.
There are biosolid composting facilities in the South and North-West that have been in operation for many years, but the site in St Leonards, should it be supported, will be the first site in the North. The construction of this site would allow local biosolids to be processed locally, whereas now they are being transported to one of the other facilities.
The new site is planned to be an aerobic windrow compost site which will convert Class 3 biosolids, into Class 2 biosolids that can be used directly on agricultural land as fertilizer and a soil enricher. The biosolid compost produced will be Class 2 biosolids, still subject to controls on its use.
Another product that is used in the composting process, are pin chips. Pin chips are the smaller splinter-like shards of wood which are leftover as a byproduct of woodchip and other timber milling processes. These, again, may end up as landfill as they are too small to be put to any other use in manufacturing.
During the 2017-18 financial year, 96.7 per cent of the biosolids generated in Tasmania was re-used, instead of going to landfill. This secondary use of two waste products (Class 3 biosolids and Pin chips) is great for the environment as they can now be recycled into useable compost for agriculture. It is where the product is suitable for use that is the question. I understand the concerns as any composting facility can, if not managed properly, produce odours and groundwater contamination or surface water runoff. This is why there is a strict and rigorous process involved in the planning and development of these sites, which has been developed over time due to the previous construction of biosolids composting sites.
Much of this angst and hurt to the people, in this case, might have been averted by openness and transparency and before the matter was listed before the council. While this Development Application has now been withdrawn due to council issues, I am advised it will be relisted shortly. The fact that pin chip material has already been dumped on-site before the DA has been considered, has not helped either.
Residents in the area involved are reliant on river and creek water for domestic use and this is a major issue and one which will need to be satisfied should the development proceed. A finding of "some risk of adverse impact" or "unlikely to significantly impact the amenity of surrounding land uses including residential receptors" (taken from the Environmental Impact Statement), does not give confidence to the residents.
An EIS is prepared as a part of the planning and development processes, to help mitigate or at least minimise the chances of these factors impacting negatively on local landholders. There is a 500-metre minimum distance threshold in place to ensure that the nearest neighbour is minimally impacted, and currently in Tasmania most nearby neighbours are over a kilometre away from any biosolids composting sites. Factors such as prevailing wind directions and speed, land topography and rain catchment, and natural vegetation shelterbelts are all considered in the EIS.
If there are any issues of concern discovered during the study, then guidelines and mitigation measures are put in place to minimise the occurrences of these possible issues. I reiterate there must be no adverse impact at all on neighbouring properties.
In the St Leonards case (the fastest growing area in Launceston), residents are asking the question: "if anything goes wrong here, odour impacts, quality of life is impacted and water supplies are polluted, who will be held accountable and what action will be available to the residents?" I note here that Conhur is a Queensland company.
With this type of development, it is essential that quality of life of the people living around it not be adversely impacted in any way. Can it be assured in this case?
Some strict guidelines and conditions need to be followed in the operation of this facility, and it is said the development must meet a high standard.
- Ivan Dean, independent Windermere MLC