Ammonia Recovery Technology

AMMONIA RECOVERY FROM LEACHATE AND WASTEWATERAmmonia separation and recovery from wastewater. Options for recovered ammonia include destruction or reuse.If

If not adequately treated, high levels of nitrate in water can have a significant environmental impact. One of the principal contaminants that must be treated in landfill leachate, and in waste water in general, is ammonia. Ammonia-N in normally present in waste water or in leachate in several forms.

Treatment is therefore essential.

Contaminated Water

Leachate generation is a major problem for municipal solid waste (MSW) landfills and causes a significant threat to surface water and groundwater.

Leachate can be defined as a liquid that passes through a landfill and ends up contaminated by interaction of toxic dissolved or suspended elements. Treatment of leachate remains one of landfill engineering’s most complex problems to solve.

Advanced Thermal Ammonia Stripping

Ammonia Stripping

Thermal stripping provides a low cost alternative to the use of carbon addition in a biological process. The thermal-stripper breaks the ammonium-ion bond with 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.

Ammonia Recovery – Acid Scrubber

An alternative to destroying the stripped ammonia is recovery with the use of an acid scrubber. The Advanced Thermal Ammonia Stripper with Ammonia Salt recovery has been developed and patented by Organics to provide a fundamental option for disposing of, or benefiting from, ammonia removed from wastewater streams. Typically, nitric, sulphuric or phosporic acid may be used to create the ammonium ion salt. In this arrangement a thermal oxidiser for ammonia-gas destruction is not required.

The single important input remains waste-heat with which to drive fracturing of the ammonium ion into ammonia gas. Such wasteheat can be taken from any suitable source, such as a gas engine’s exhaust, excess process steam or any other heat-source where energy is available for disposal. Once the process is commenced, the exothermic reaction encountered in salt formation offers the potential of significant energy savings.

Ammonia Recovery – Water Scrubber

An alternative to destroying the stripped ammonia is recovery with the use of an acid scrubber. The Advanced Thermal Ammonia Stripper with Ammonia Salt recovery has been developed and patented by Organics to provide a fundamental option for disposing of, or benefiting from, ammonia removed from wastewater streams. Typically, nitric, sulphuric or phosporic acid may be used to create the ammonium ion salt.

In this arrangement a thermal oxidiser for ammonia-gas destruction is not required. The single important input remains waste-heat with which to drive fracturing of the ammonium ion into ammonia gas. Such wasteheat can be taken from any suitable source, such as a gas engine’s exhaust, excess process steam or any other heat-source where energy is available for disposal. Once the process is commenced, the exothermic reaction encountered in salt formation offers the potential of significant energy savings.

A UNIQUE APPROACH TO AN AGE-OLD PROBLEM

Thermally-driven ammonia stripping was developed by Organics to offer an alternative route to that of pH adjustment for continuous-process ammonia stripping.

With a thermally-driven stripper no chemical additions are required, apart from the minor addition of anti-foam agent. The single important input is waste-heat with which to drive the chemical reactions.

If waste-heat is not available, the fuel-cost can be as prohibitive as that of chemical additions or carbon source requirements. Where waste-heat is available, from an engine-exhaust or unwanted biogas, the long-term operating cost can be confined to plant operation and maintenance, including electricity costs.

The preferred option within the Organics process is to use the feed ammonia-laden air directly into the combustion air in the heat-raising process. By this means ammonia gas is destroyed as a part of the process of thermally powering the system.