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Council and municipal bodies have historically collected mixed waste and put it straight into landfill. However this is becoming increasingly problematic due to rising gate fees, higher transport costs and tighter regulatory controls. Especially in countries like Australia where there are high landfill levies (NSW) and strict environmental guidelines (VIC). Progressive councils are collecting source separated materials (organics and recyclables) and closing the loop by converting kitchen and garden waste into compost, a valuable and renewable resource.


Global Composting Solutions offers a proven technology backed by 14 years of in-vessel composting experience. The modularity and scalability of the HotRot system, utilising either the HotRot 1811 or HotRot 3518 composting units, allow the establishment of composting facilities capable of processing up to 60 tonne of material per day. Global Composting is promoting the “composting system you want when you don’t want a composting system” – a system that is designed to take into account technical, environmental and aesthetic considerations.

Other technologies may offer larger capacity facilities but care must be exercised in siting any composting plant in order to minimise local impacts and transportation costs for both waste and compost (planning an organic resource recovery facility). The modularity of the HotRot system also allows a municipality to start with a smaller capacity plant and easily expand as collection services are introduced more widely or to cater for population growth.

The economic analysis of composting, or alternative forms of waste treatment, must include a comparison of full costs: by default the cost to landfill waste is often the benchmark.

Anaerobic digestion (AD) can be a popular choice but the economic justification is often based on feed-in tariffs for electricity generation. Potential benefits are often inflated by these tariffs being applied to gross power production rather than net power production. Power consumption for some AD plants is significant (50-70% of gross) and the cost of generating electricity from waste should be carefully balanced against other forms of sustainable power generation.

'Whole of Life' Cost Benefits

HotRot, like any enclosed composting system, may appear to have a higher capital cost when compared to open-windrow or other low tech alternatives but land costs are often ignored and “whole of life” costs can be favourable.

Plus a cheap composting plant becomes very expensive if it is forced to close because of odour or other environmental issues.

Technical and Environmental Benefits = Favourable Plant Economics

HotRot technology provides a significant number of technical and environmental benefits, which translate into favourable plant economics. Global Composting's unique contractual odour-free guarantee also offers a municipality a form of insurance.

Less Labour, Less Space Required

The HotRot system requires 50% less direct labour with overall operating costs around 25% lower than other comparable enclosed composting systems. This is due to low maintenance and power costs and the elimination of leachate. Because of the HotRot system’s ability to produce stable compost relatively quickly, a HotRot facility requires 50-75% less space than comparable systems, providing flexibility and lower facility costs for the location of the plant.

Odour Free - Guaranteed

The Global Composting Contractual OdourFree Guarantee also ensures that buffer distances can be minimised or eliminated.

Integrated Composting Solutions including DBOO

Global Composting can work with its clients to design an integrated composting solution from waste collection through receivals, composting and final product distribution and use.

We will consider all forms of contract from design/build (DB) through to design, build, own and operate (DBOO).

Technical Features And Benefits


Organic waste treatment plants based on HotRot composting technology offer a number of technical advantages.

The technology can be considered as the latest evolution of composting and the system was designed to overcome many of the engineering and environmental limitations of older technology (HotRot a new generation composting system).

The HotRot technology can be established as a standalone facility or co-located with other waste management activities such as waste transfer stations and landfills. Co-location with a waste transfer station can minimise waste and product transportation costs as well as offer operational savings for both activities.

The HotRot technology is also complementary to technology such as anaerobic digestion where there is often a need to compost digestate from the AD process. A hybrid liquid-AD and HotRot composting system has been developed by HotRot and is ideal for handling high moisture commercial (IC&I) food and organic waste (Hybrid system process flow chart).

HotRot is a fully enclosed high-rate in-vessel composting system. HotRot offers a compact footprint, low operating costs, and a leachate and odour-free process.

A typical composting plant consists of:
  • Waste reception building – pre-sorting/inspection, shredding, waste and amendment storage. This normally houses the integrated feed hoppers that automatically "feed" the HotRot units.

  • External HotRot composting units – HotRot units are designed for outdoor installation and do not require additional buildings or weather protection.

  • Temporary compost product storage – these are bunkers immediately to the rear of the HotRot units where compost from the HotRot units is automatically received.

  • On-site product storage – this is typically in passive windrows or piles; because the compost discharge from the HotRot units is mature (Typical Compost Quality) on site storage is minimised (generally only 2-4 weeks), active turning is not required and overall plant area reduced by 50%.

  • Product screening – generally used to recover larger over-sized bulker and amendment for re-processing through the composting units and separation of different size fractions of compost depending on market requirements.

The design of a typical municipal HotRot composting facility can be viewed here (SSO plant animation and composting SSO flow chart) and details about the HotRot technology is outlined in a series of three documents here (Part 1Part 2 and Part 3).



Environmental Benefits

HotRot has been described as the composting system you want when you don’t want a composting system. It is clean and tidy, fully enclosed, does not produce leachate (a major source of odour and pollution) and is provided with a contractual odour-free guarantee.

Systems have been installed on university campuses, adjacent to public areas at zoos and at municipal waste transfer stations - all situations only made possible by the system's control over all environmental impacts (environmental discharges).

Clean and Odour Free

The clean design and odour-free guarantee provides comfort to planners and policy makers making site permitting less arduous. HotRot systems offer full instrumentation, monitoring for process temperatures to throughput, CO2 release (as a direct measure of microbial respiration) and other key performance indicators.

Composting itself offers a number of environmental and social benefits (Part1). Fundamentally there have also been some legislative changes over the last few years driving change in behaviour. Australia has introduced its emissions trading scheme (ETC) and backed off artificial subsidies (in-feed tariffs) for so-called green energy.

Some North Eastern US states are introducing legislative bans on the disposal of organics and more importantly food waste from landfill. Mayor Bloomberg of New York called for just such a ban and a move to composting and anaerobic digestion on his departure from office.

Supporting Job Creation

The editorial in the May 2013 edition of Biocycle highlighted a recent study by the Institute for Local Self-Reliancein Maryland which found that 1,400 new full-time jobs could be supported in the state for every million tons of yard trimmings and food scraps converted to compost.

Increased Crop Yields

A New Zealand study, released about the same time and carried out by Plant & Food Research, showed that adding compost (from food and yard waste) increased the yields of arable crops by up to 14% and forage crops by up to 50%.

Effective in Reducing Greenhouse Gas Emissions

Composting is an essential tool in reducing greenhouse gas (GHG) emissions from waste disposal. The USEPA reported that composting could reduce GHG emissions by 0.9-1.0 tonnes of CO2 equivalents for every tonne of food waste composted, when compared to landfill with gas capture (EPAStudySolidWasteandGHG).

Neither landfill with gas capture or anaerobic digestion can beat composting for GHG emission reduction potential. The recent push towards these technologies in certain regions is often false economy, as even where electricity generation is involved these systems are artificially subsidised and the true cost of the power is often significantly higher than more traditional and new sustainable electricity generation methods (US levelised electricity generation cost).

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