Ammonia Stripping and Recovery Systems

There are two methods used for the removal of ammonia from wastewater or landfill leachate by means of air stripping. The first involves raising the pH to around 12. This type of ammonia stripping is referred to as ‘pH driven’. The second involves raising the temperature using waste heat in the form of exhaust gas from on-site engines or by directly burning waste gas, including biogas. This type of stripping is referred to as ‘thermally driven’ ammonia stripping.

Where waste heat is available, the latter method is substantially lower in cost as chemical adjustment is not required. Where waste heat is not available, it may be cheaper to employ this type of stripping, although this will depend on the availability of  the necessary chemicals. 

Organics has experience in the supply and installation of both types of stripping systems and is able to advise both on plant installation costs and long-term operational costs.

Advanced Thermal Ammonia Stripping

Thermal ammonia stripping breaks the ammonium-ion bond using heat alone. This action converts ammonia into a gas, NH3, which can be driven from the liquid phase with suitable quantities of air.

In a single pass, it is possible to achieve greater than 98.5% removal of ammonia by this mechanism.

Organics has developed a low-NOx combustion process for flaring waste gas which involves Exhaust Gas Recycle. When combined with the thermal destruction of ammonia gases the result is extremely low NOx emission levels. Heat from the thermal-oxidiser used to destroy ammonia is recovered in conventional heat-recovery economisers and used to power the thermal ammonia stripper.

Biogas Feed Train

The composition of biogas is comprised mostly of

• methane, at between 40% and 65% by volume
• carbon dioxide, at between 30% and 40% by volume
• trace gases

A biogas feed train will consist of a gas blower, normally with automatic feed or suction pressure control and equipment to treat the biogas. Treatment may be in the form of reducing trace gas composition, reducing or removing bulk gases, drying the biogas to acceptable levels of moisture content, and filtering the particulates from the biogas.

Organics offers a range of such technologies to prepare biogas for use. With the correct application of this technology, biogas can become a reliable fuel for long-term economic use.

Landfill Gas Flare Systems

Landfill gas flaring is a tried and tested mechanism to control a highly polluting greenhouse gas. If a flare is installed as part of a landfill gas utilisation system, it provides a mechanism for ensuring complete protection from gas migration and escape during period of down-time for maintenance, etc. 

The control and use of landfill gas is an excellent example of the circular economy in action in that resources are recycled not only to meet our daily activities but also to reduce our carbon footprint.

Organics has been involved in landfill gas control as well as power generation since 1985. We have experience not only in power generation techniques but also in the production of biomethane, a clean fuel that can be used in vehicles or exported to a natural gas grid.

Waste as an Energy Resource

Organics has been in the waste-as-a-resource business for over thirty years. During this time the company has provided over three hundred projects around the world and has provided equipment to make beneficial use of a wide range of waste materials. It has been a logical extension of Organics’ scope to develop Refuse Derived Fuel (RDF) equipment and facilities, which are now considered to be an essential and integral part of today’s waste stream management.

Organics also has extensive experience in the development of many other technologies that are used in the management of waste including anaerobic digestion systems, gasification and pyrolysis. In particular, we have been active in the design and installation of large-scale AD plant for the treatment of effluent from the production of palm oil and tapioca.

SMART Low NOx Flares

Performance NOx – When operating at its peak settings, the Organics SMART flare will achieve emmissions of less than 25 mg/Nm3 (dry gas at 3% Oxygen). At 50% methane this latter is approximately equivalent to a Mass Emission Rate of .025 lb Nox/MMBtu.

Carbon Monoxide – Levels of carbon monoxide will be below 40 mg/Nm3 (dry gas at 3% oxygen), which is approximately equivalent to a Mass Emission Rate of 0.6 lb/MMBtu at 50% methane.

Trace gases – Vinyl chloride, benzene and non-methane organic carbons have all been measured by a NAMAS approved laboratory to be destroyed to greater than 98% efficiency.

Ammonia – When input to a thermal oxidiser equipped with SMART flare technology, an inlet concentration of mg/Nm3 (dry gas 3% oxygen) resulted in a 99.95% removal efficiency and a total Nox load of <100 mg/Nm3.

This latter is well within the requirements of the German TA Luft and the propoesed UK Environment Agency Landfill gas emission standards.