For each land, region, waste stream and application of compost other quality standards apply for compost or biological dried waste material. NALG customers market their compost under the most stringent norms of EPA and DEP (USA and Australia) and is certified to AS4454 composting order.

The NALG system has always received governmental approval. NALG designed turnkey installations have met all demands for compost quality marks.



Many pathogens such as Salmonella, E. Colli bacteria, weed seeds, Tabacco Mosaic Virus and others become either largely non-toxic or entirely harmless under the influence of the climate control in NALG Invessel composting tunnels. By obtaining the right relation between temperature, time, moisture, oxygen and ammonia a quick destruction of pathogens is assured. Since NALG Invessel tunnels are enclosed, and no people, animals or machines enter the tunnels while the process lasts, pasteurised material comes out clean.


Depending on the length of the process, stability of the compost can be adapted according the demands of the compost-client.. By mixing well, moisturising on time and setting the right climate with the NALG composting control system, the appropriate stability can be obtained within a small timeframe in NALG tunnels.

For biological drying of waste, the caloric value from the final product is an important aspect. In a short time, the caloric value of the waste goes up drastically in NALG designed tunnels. The main reason is the vaporisation of moisture. In the same short time, volume and weight reduce rapidly, the material is pasteurised and the negative aspects of organic waste in a waste stream (nasty odour, harmful pathogens, pest survival, animal attraction, methane and leachate production) are reduced radically.

Air purification

A NALG composting installation is build meeting customers demands and legal requirements. The first step is to design a composting facility that produces as few odour as possible. For the remaining odour NALG designs and builds different air cleaning systems for different purposes;

  • Water scrubbers
  • Ammonia scrubbers
  • Bio filters
  • Chimney
  • Other scrubbers

Water scrubbers

Composting without water is impossible. Bacteria taking care of the composting process require water to grow. In a composting facility part of the water comes back as condensation water and process water. This water is used in the first step of cleaning exhaust air from the tunnels. Added with rain water, ground water and drinking water this water is used in waterscrubbers to humidify process air before it goes to the biofilter. Humidification is required to keep the bacteria that live in the biofilter alive.

Most NALG composting facilities use water. This means no water needs to be pumped to a water treatment facility.

Biofilter, Ammonia scrubber and Straw filter

Bio filter

After a water scrubber a biofilter is placed. Air is blown into the biofilter with very low speed. Bacteria use the odorous compounds of the air for their own survival in the filter and convert this odour part to a less or neutral smelling. That is why NALG composting facilities can operate in areas where there are strict limitations for odour emission.

Ammonia scrubber

In the composting processes where ammonia is being produced in high concentrations a biofilter alone is not sufficient. The ammonia would kill the bacterial life in the biofilter. Therefore this air is first treated with an ammonia scrubber. Using acid the ammonia is collected and removed from the process air. The removed ammonia can be reused in the composting process for making mushroom compost.
NALG Ammonia scrubbers are always equipped with a water scrubber, to prevent the concrete and iron works being destructed by the acids.

NALG ammonia scrubbers are used in the following situations;

Fermentation process for mushroom compost;
Pasteurisation tunnels for mushroom compost;
Composting tunnels for sludge;
Composting tunnels for waste containing a high level of ammonia

Straw filter

Especially for the exhaust air of mushroom composting facilities NALG designs a straw absorption filter. NALG was the first company in the world to design this system, where loosened straw is used as biofilter material. After several weeks the straw will be used in the mixing process and is replaced by new straw on the filter.

The following benefits are the result of a strawfilter:
Smell is being reduced for larger parts;
Ammonia will be transformed into the straw. This way the nitrogen is brought back into the composting process and the nitrogen cycle is complete;
The straw gets softer, so the composting process accelerates



Drying manure in tunnels

The drying and sanitizing of manure in tunnels is a technique developed by NALG. By starting the composting proces in the tunnels the manure is pasteurised and for an important part biologically dried. When the biology slows down the drying process is continued automatically with thermal heat. In several days manure is pasteurised and dried up to compost with a  low moisture content. This pasteurised and dried material can than be processed into pellets or granular, after which the minerals in these pellets can be sold as a valuable and homogenous fertiliser.


Mushroom substrate 

NALG designs and builds fermentation facilities for individual mushroom farms, and also for central composting facilities. Vision is a magic word in this. Because of this vision future expansions are always possible. By doing this it is always possible to produce mushroom compost even when the environment regulations are on a high level. NALG takes benefit of the fact that lot of expertise is gained from the waste composting market.

The first phase in making mushroom compost is a speciality of NALG. For this aerated floors, bunkers and indoor tunnels are build. Aeration takes place by using the by NALG designed spicket system.

The production of different kinds of mushroom compost is possible in three phases:

  • Phase I Fermentation

  • Phase II Pastuerisation

  • Phase III Spawn run tunnels

NALG Integrated Composting Software:

The process is controlled by the G-2000 system. The operating system has many possibilities. Reducing energy consumption best results are possible. The G-2000 system provides flexibility which suits any individual mushroom farm operator.

Mushroom farms

The climate units are designed keeping in mind a long lifecycle, reliability, aerodynamics and low energy consumption. NALG offers turn-key, and if desired pre-fab, solutions for mushroom farms. NALG can deliver for mushroom farms the following items:

  • Design of the mushroom farm;

  • Airhandling units;

  • Cooling and heating;

  • Humidification using either water or steam;

  • Climate control systems;

  • Other civil works and other electrical works if requested