What is AquaCritox?

Using our patented hydrothermal oxidation process, AquaCritox mineralises wet waste (such as biosolids) – converting it to carbon dioxide, elemental nitrogen, water and a small quantity of nutrient-rich, inert and odourless solid residue. AquaCritox also allows for the recovery of clean energy that would normally be lost during sludge disposal.

AquaCritox can be used to treat a variety of waste streams, including primary and secondary biosolids and drinking water sludges: providing safe, sustainable and cost-effective disposal.

How does it work?

Very simply, hydrothermal oxidation (HTO) combines specific temperature and pressure levels with an oxygen supply to oxidise the organic components present in wet waste. This produces carbon dioxide, nitrogen, water and a mineral residue. HTO typically reduces waste volume by up to 97%, and makes it safe for disposal through conventional routes. What’s more, it allows for the recovery of valuable resources and generates thermal energy, which can be used to produce renewable heat and/or power.

The process

Process diagram ORIGINAL
  1. The incoming waste stream is pumped up to the required pressure (221 bar (3,205 psi)) using a high-pressure pump.
  2. The pressurised feed is then passed through a heat exchanger, where it is brought up to temperature (normally 374°C (705.5°F)). Once the HTO process is underway, AquaCritox uses energy recovered from the reactor itself to heat the incoming waste stream.
  3. Raising the feed temperature and pressure to these levels causes water to behave in a completely different manner, and it becomes a perfect reaction medium. Pressurised liquid oxygen (LOX) is then introduced into the hot pressurised feed, causing an almost immediate oxidation reaction. This reaction will reach complete stoichiometric oxidation within a matter of seconds.
  4. The oxidation reaction is exothermic: by releasing the energy embedded within the waste, HTO continues to generate more thermal energy than it actually needs. This creates a steady source of steam that can be used to produce renewable electricity or hot water.
  5. AquaCritox converts any organics present in the waste stream into inert by-products (CO2, nitrogen, clean water and an odourless residue). After processing, the remaining treated effluent is safe for sewer disposal. Any inorganic materials can be easily separated and treated in a separate step to recover valuable resources.

Read more: The key benefits of AquaCritox, and how it’s solving the problems currently faced by the water industry.