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Process Description
The ArrowBio Process can be divided into two distinct phases:

1. Water based separation and organic pre-treatment
2. Anaerobic digestion, water cleaning and energy generation

In the first section (a water-based MRF) the unsorted waste is processed directly as tipped from the collection truck. Organic and inorganic materials are separated through a unique, liquid-based technology, involving settling, washing and hydro-mechanical shredding of organic solids.

In other waste treatment technologies such as incineration and composting, energy is required to remove water from the waste stream. However ArrowBio utilises liquids to their full potential.

The first stage end products are clean recyclable elements such as glass, ferrous and non-ferrous metals and plastic (separated into PET, HDPE & film plastic). These resources can be sent for recycling without need for further treatment.

Items such as batteries are carefully removed, without breakage, thereby voiding leakage of potentially toxic materials. The other intermediary product is a dilute organic stream now ready for the next, biological stage. The first stage thus performs two functions; separation and preparation of the waste, without additional machinery or effort.

In addition to removing inorganic and other non-biodegradable materials, the liquid-based separation simultaneously conditions the organic material for rapid biological action. This is accomplished by bringing the organic matter into solution or fine suspension. This slurry is very rich with a chemical oxygen demand.

In the second stage the liquid is then sent to a series of tanks which support the high-rate transformation of the organic wastes to biogas (on average 75% CH4). This process is facilitated by naturally occurring microbial communities, in two highly controlled sequential bioreactors. ArrowBio utilises an advanced variant anaerobic digestion technique called up-flow anaerobic sludge blanket (UASB) digestion. Biogas production by this method far exceeds in-house energy needs.

The solid organic matter is thoroughly stabilised and usable directly as an organic fertiliser. Excess water is either cleaned and removed from the system or recycled and sent as liquid to the upfront separation stage, and so the system is autonomous with respect to energy and water.

The biogas is consumed by electricity generators, producing five times the electricity the plant requires to operate.



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