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Under ideal conditions, composting proceeds through three major phases:

  • An initial, mesophilic phase, in which the decomposition is carried out under moderate temperatures by mesophilic microorganisms.

  • As the temperature rises, a second, thermophilic phase starts, in which the decomposition is carried out by various thermophilic bacteria under high temperatures.

  • As the supply of high-energy compounds dwindles, the temperature starts to decrease, and the mesophiles once again predominate in the maturation phase.

Composting can destroy pathogens or unwanted seeds. Unwanted living plants (or weeds) can be discouraged by covering with mulch/compost. The "microbial pesticides" in compost may include thermophiles and mesophiles.

Thermophilic (high-temperature) composting is well known to destroy many seeds and nearly all types of pathogens (exceptions may include prions). The sanitizing qualities of (thermophilic) composting are desirable where there is a high likelihood of pathogens, such as with manure.

Organic solid waste (green waste)


A large compost pile that is steaming with the heat generated by thermophilicmicroorganisms.

Composting is a process for converting decomposable organic materials into useful stable products. Therefore, valuable landfill space can be used for other wastes by composting these materials rather than dumping them on landfills. It may however be difficult to control inert and plastics contamination from municipal solid waste.

Co-composting is a technique that processes organic solid waste together with other input materials such as dewatered fecal sludge or sewage sludge.

Industrial composting systems are being installed to treat organic solid waste and recycle it rather than landfilling it. It is one example of an advanced waste processing system. Mechanical sorting of mixed waste streams combined with anaerobic digestion or in-vessel composting is called mechanical biological treatment. It is increasingly being used in developed countries due to regulations controlling the amount of organic matter allowed in landfills. Treating biodegradable waste before it enters a landfill reduces global warming from fugitive methane; untreated waste breaks down anaerobically in a landfill, producing landfill gas that contains methane, a potent greenhouse gas.

Animal manure and bedding

On many farms, the basic composting ingredients are animal manure generated on the farm and bedding. Straw and sawdust are common bedding materials. Non-traditional bedding materials are also used, including newspaper and chopped cardboard. The amount of manure composted on a livestock farm is often determined by cleaning schedules, land availability, and weather conditions. Each type of manure has its own physical, chemical, and biological characteristics. Cattle and horse manures, when mixed with bedding, possess good qualities for composting. Swine manure, which is very wet and usually not mixed with bedding material, must be mixed with straw or similar raw materials. Poultry manure also must be blended with carbonaceous materials - those low in nitrogen preferred, such as sawdust or straw.

Human excreta and sewage sludge

Human excrement can also be added as an input to the composting process since human excreta is a nitrogen-rich organic material. It can be either composted directly, like in composting toilets. Or the human excreta can be composted indirectly (as sewage sludge), after it has undergone treatment in a sewage treatment plant.

Urine can be put on compost piles or directly used as fertilizer. Adding urine to compost can increase temperatures and therefore increase its ability to destroy pathogens and unwanted seeds. Unlike feces, urine does not attract disease-spreading flies (such as houseflies or blow flies), and it does not contain the most hardy of pathogens, such as parasitic worm eggs. Urine usually does not smell for long, particularly when it is fresh, diluted, or put on sorbents.

Uses of Compost

Compost can be used as an additive to soil, or other matrices such as coir and peat, as a tilth improver, supplying humus and nutrients. It provides a rich growing medium, or a porous, absorbent material that holds moisture and soluble minerals, providing the support and nutrients in which plants can flourish, although it is rarely used alone, being primarily mixed with soil, sand, grit, bark chips, vermiculite, perlite, or clay granules to produce loam. Compost can be tilled directly into the soil or growing medium to boost the level of organic matter and the overall fertility of the soil. Compost that is ready to be used as an additive is dark brown or even black with an earthy smell.

Generally, direct seeding into a compost is not recommended due to the speed with which it may dry and the possible presence of phytotoxins in immature compost that may inhibit germination, and the possible tie up of nitrogen by incompletely decomposed lignin. It is very common to see blends of 20–30% compost used for transplanting seedlings at cotyledon stage or later.

Text is from Wikipedia, thanks Wiki.

This is the start of our first hot water system. we are using 3 x stainless steel tanks as SS won't rust or oxidise in the compost. It's also easily taken apart rather than when using coils and coils of pipe.

Please see the recipe below, tried and tested by Mr John Herman himself.

The Recipe

Hot Water from Premium Compost  5/9/17

Thanks, Mr John Herman.


Another option for showering has emerged for the residents of the Hermans household. Whilst there is no problem with our bathroom and its domestic supply of solar hot water (with wood fire boosting over winter months), we now have an outdoor garden shower using water heated by compost. 


Buried in the centre of the compost pile is a stainless steel cylinder which stores the heating water.  With a suitable combination of materials in the pile, bacteria and fungi break down the organic matter, releasing chemical energy from sugars, starches (and some proteins) at such a rate that the temperature is capable of reaching 70 degrees C. The microbes that dominate this process are regarded as thermophiles, for only they can withstand the high temperatures generated by the molecular breakdown of the organic food feast. 


That compost pile, and those around it, are the result of my research into making the most nutrient rich garden compost that I can produce. 


About a year ago I met a commercial compost maker who was rapidly building a vast mountain of high quality soil rejuvenating compost. Compost Phil had a bi-weekly run through the metro area with a mechanical press on the back of a large truck, capable of picking up many tonnes of organic waste.  Impressed by both the scale of operation and by the size of the weed plants growing around the edge of his nutrient generating facility, I was intrigued to learn more. After several 3am start pick up runs as assistant bin runner, Phil taught me the secrets to a premium compost mix.


Since then I have been perfecting my own high nutrient value compost for the garden. The preferred materials in my mix are roughly; 

50% well-shredded garden prunings and various other organic waste materials, some dry carbon rich and some green with more nitrogen content. 

10% biochar (made from around the house leaf and stick litter reduction), 

10% red clay (for humus formation, from sub-soil removals), 

5% compost from a finished pile (to inoculate with fresh microbes), 

5% finely crushed sea shells (from a fish shop), 

5% glycerine (from biodiesel processing waste, any biodiesel maker will happily give you this biproduct, pure microbial food!), 

5% basalt dust (where ever you can get it!), 

5% of the secret ingredient, ‘fish offal’ (from any fish monger’s shop, they will be so pleased to see you!)

Compost made with such a range of ingredients creates a nutrient rich soil additive with a high Cation Exchange Capacity.

With the use of a pitchfork the ingredients are thoroughly mixed and water/ glycerine is added at this time, to make a moist but not saturated heap.

If you are just chasing heat and not so concerned about all of those other plant nutrient values of compost, then try 90% well-shredded organic matter and 10% animal waste. Fish offal is easy to get and already in small bits, plus you are taking its disposal away from landfill. On one occasion I buried a road kill wallaby under the water tank, and the water temperature went above bearable in a few days! I am emphasizing well shredded for the vegetative material; this gets the surface area ratio to a high level, allowing microbes to work at their maximum capacity. The bigger the pile is, the better it will work. Surface area to volume ratio decreases minimizing heat loss. Covering the pile with old carpet stops both heat loss and moisture loss.


If you get your mix right, not only could you create a fantastically nutrient rich garden compost, but if you put your water pipes in the right place you could also score a highly effective Hot Water System.


Burying coils of poly-pipe within the pile gives no volumetric storage and is difficult to remove and reset in the next pile. The heat exchange system that I found to be most user-friendly was made from a 100litre HWS with the 

outer insulation removed.  This small steel, glass lined tank should be laid flat at the bottom of the compost pile, with the hot water outlet at a high point and the cold inlet at a low point.

Because I am making compost at a constant rate, (garden waste just keeps coming, and must be returned to my soil in its best form) there is a succession 

of piles that have heat delivery potential. I made a second  heat transfer tank  to bury in the next successive pile. This second tank set up means we can have endless hot water by simply swapping the hose fittings over once the temperature in the older pile starts dropping below a comfortable level. Hot  water is often generated for many months even with two people showering daily.

It is also worth noting that within about 6 months the size of your original pile will drop to about a half. This is the result of  carbon being respired as CO2 by the active microbes. It’s an unavoidable release of carbon to the atmosphere, but you have both captured some of the energy involved in those reactions, and returned valuable plant nutrients to productive garden soil, which negates the need to purchase inorganic or other soil conditioners. As the carbon is released at a greater rate than the nitrogen, the C/N ratio constantly rises.


In mid July we were away on a 10 day trip up north in our veggie oil powered van. Upon returning, despite widespread severe frosts, our next use of the shower was hard to bear, due to excessively high water temperature! In the past I had not included a mixing valve with a cold option, but if you have the sort of performance that we sometimes get, it may be necessary. 


It’s a heavily used shower along with our outdoor bath and dry pit toilet.

Although we have indoor facilities, we choose the outdoor life….