The N-Viro process is a
patented biosolids stabilisation technology licensed to Bio-Recycle
within Australia, New Zealand and Singapore.
The process produces
a valuable and versatile soil-like material which is widely used
within agricultural, landscaping and land rehabilitation markets.
more than 40 facilities in the U.S., Canada, the United Kingdom,
Australia and Belgium produce over 1,000,000 tonnes of N-Viro Soil
The N-Viro process is approved by the NSW EPA as a Grade A biosolids
stabilisation process. It utilises a high pH, high temperature,
high solids process to pasteurise, rather than sterilise, the biosolids.
Within the process, alkaline and mineral reagents are combined to
induce a number of stresses within the biosolids. Specifically,
the N-Viro process utilises dry by-products such as cement kiln
dust (CKD), quick lime, agricultural lime, power station fly ash,
lime kiln dust (LKD) and evenwood ash and spent lime from water
treatment to induce the chemical and physical changes within the
biosolids. The great surface area of the combined alkaline reagents
is also able to deodorise the biosolids material.
Following the addition of these alkaline reagents
to either digested or undigested biosolids, a number of changes
rapidly occur. The pH of the biosolids is raised to 12 or greater,
and remains at that level for 72 hours. During at least 12 hours
of this initial 72 hour period, the temperature within the biosolids
is raised to between 52†C and 62†C by the exothermic conversion
of CaO or MgO to their hydroxides. After 72 hours, the combined
solids content of the mix will have risen to 50% or greater. A second
variation to the process raises the pH of the biosolids mix to 12
or greater for 7 days, or until the solids content of the mix reaches
60%. The mix should then be air-dried for at least 30 days to further
raise the solids to at least 65%. N-Viro Soil is now ready to be
applied to the soil.
The combined effect of the chemical and physical changes induced
within the biosolids alters the biological nature of the biosolids.
As a result, desirable species of bacteria are preserved as an aid
against future re-infection. Once produced, N-Viro Soil may be stored
in the open without threat of biological re-invasion.
N-Viro Soil offers many benefits to the market place. These include:
of soil structure and hence drainage and water retention.
of acid soils.
of both macro (N, P, K, S, Ca) and micro nutrients to the soil.
physical, chemical and biological properties.
N-Viro Soil has
been utilised within many land application projects. In addition
to having a lower concentration of harmful hydroxides than other
alkaline biosolids products, when N-Viro Soil is allowed to age
in the open, the hydroxides of Ca and Mg carbonate, thereby lowering
the pH of the material to much nearer neutral. In this aged state,
N-Viro Soil has been used as a complete topsoil replacement material
in situations including rehabilitation of open-cut mines and disturbed
lands (such as embankments and closed landfills, playing fields
and parks and gardens). In its fresh state, N-Viro Soil has been
used extensively in both agriculture and green waste management
Within waste management, fresh N-Viro Soil accelerates the composting
process when mixed with a combination of leaf mulch, green or wood
waste. N-Viro Soil usually contains around 45% of the liming value
of agricultural lime, and is sold as a liming agent with added organic
matter and slow release nutrients within NSW and QLD.
Some agricultural applications of N-Viro Soil have included cotton,
wheat, barley, canola, sorghum, millet, sugar cane, peanut, oat,
pasture, lucerne, apple, nectarine, vineyard, macadamia, avocado,
banana, watermelon, rockmelon, tomato, eggplant, squash, broccoli
and cabbage production.