Green Waste, Organic Compost, Soil Conditioner, Clinical Waste, Hygiene Services, Kerbside Recycling
Welcome to Western Composting Technology
Western Composting Technology develops, designs, manufactures, and operates facilities for accelerated composting in tunnels, with a process based on computer controlled climatisation units.
The tunnel composting system was originally developed for the mushroom industry in the late 70’s, and the treatment of different waste streams are basically new applications of an existing technique. Mushroom production is highly depending on the quality of the growing substrate, the compost. There is a direct relation between compost quality and the amount of mushrooms per growing area, and thus income from the crop. It is therefore of great importance to create conditions that allow sufficient process control to obtain a stable, high quality compost . This had led to development from open, extensive and marginally controllable ways of composting, to the closed tunnel system. The personal computer made continuous control feasible. The investments that are required can be justified by improved compost quality, a faster composting process, feedstock flexibility and positive environmental and social sustainability outcomes.
The tunnel composting process is completely closed and the process control is optimised, which results in a very short processing time. The process works on the principle of composting one batch of waste at a time under highly controlled conditions. The control of the composting environment is brought about by means of a re-circulated forced air supply system under computer control. This allows temperatures throughout the composting mass to be kept within 2-30C of that required for the different stages of the composting process. This in turn allows a fine manipulation of the microbiology of the composting process to bring about an optimum composting regime and to produce a tightly specified compost product. Composting is normally complete within 21 days.
Some of the advantages of the system are provided below:
- Excellent process control, which minimises the retention time and thus the size of the facility. The optimised process conditions ensure a fast degradation of easily decomposable organic material, which results in a nearly odourless product after only three weeks of composting. It is a highly sophisticated yet easy to manage process control system. Furthermore, the degree of control is greater than for open or containerised systems because the number of control points is generally higher.
- Flexibility towards input material and end products and thus towards different markets. Since the tunnels work individually, it is possible to process different types of waste and/or produce different types of compost simultaneously with different feedstocks.
- In the case of sewage sludge and food waste that are a source of potential human pathogens, the composting process must be designed to maximise pasteurisation of the material. This can only be achieved with full containment in order to achieve process control and uniform pasteurisation.
- Sophisticated odour control by use of humidifier/scrubber and biofilters. Due to the forced aeration with a very high airflow there is a very small risk of local anaerobic conditions that may create smelling H2S. Re-circulation of air promotes capture and breakdown of volatiles. The Waste Treatment Technologies process design meets the Dutch standard for odour control, which due to the high density of the population are amongst the strictest in the world (10 OU/m3 as 98th percentile).
- For source-separated organics and dewatered biosolids there is no waste water effluent. All leachate is brought back to the tunnel, and water leaving the system only in its evaporated form through the biofilter.
- No devices in the process room – only the tunnel walls are exposed to the aggressive process air. At the same time, this aggressive surrounding is not part of the working environment, and it does not affect the building structure.
- Up-scaling is uncomplicated since a plant is built up by a number of relatively small, individually controlled units.
- The system is suitable for a wide range of capacities.
Compost projects fail for a number of reasons: lack of proper project finance; selection of inappropriate technology for the waste types and characteristics; insufficient technical knowledge and experience to run the composting process under optimum conditions; poor community acceptance normally due to poor odour control and, lack of product market. The first and the last come down to good management, but some systems are more prone to problems than others.
Whilst the use of open systems is generally acceptable for garden organics, more tunnel systems are being used for food waste and, for sewage sludge their use is virtually universal. There are inherent weaknesses in the aerated static pile and anaerobic systems due to the length of time taken to process each batch, the possibility of fugitive emissions and building corrosion for the more putrescible wastes and in the case of the later, poor compost quality that does not meet the Australian standard.
As an underlying principle, the higher the capital investment, the shorter the composting period may be as well as the potential for control of the end-product quality. For horticultural markets, where there is a requirement for composted material having particular attributes, relatively high investment systems are preferred. In regard to agricultural use, compost application to land may be part of an overall fertiliser strategy. As such, the nutrient content of composted materials should be known before land application, and the balance of nutrients applied as fertiliser. With respect to landscape use, nutrient content of the compost may not be relevant and the aesthetic appearance and freedom from weed seeds, pest and disease and structural properties of the compost are more significant.
Western Composting technology is particularly proud of its achievements on the Shepparton project. Innovation has been driven by our desire to not only be an industry leader but to continually improve. We have set new standards for product quality, work place safety and environmental management as evidenced by our certification to AS/NZS ISO9001:2008, AS/NZS 14001:2004 and AS/NZS 4801:2001. In addition, in March 2010 the Victorian Environment Protection Authority amended the conditions of our waste discharge license to increase the capacity of the facility to process up to 20,000 tonnes garden organics and food waste from commercial and industrial premises.
During the compositng process the tunnel is under slight negative pressure,
preventing the emission of malodourous and volatile organic compounds. All air
down from the process passes through a himidifier 'scrubber' and biofilter before
being released to the atmosphere
