Ammonia recovery from anaerobically digested cattle manure by steam stripping

Abstract

Ammonia recovery from anaerobically digested cattle manure effluents through steam stripping was studied at a stripping tower temperature of 98-99 degrees C and a steam-water ratio approximately 56-72 g/L. The digested manure effluents were first treated by microfiltration and then the permeate was used as feed in steam stripping. The stripping performance was evaluated under different feed pH values, ammonia concentrations and temperatures. The increase of the initial feed pH does not significantly improve ammonia stripping efficiency due to the fact that the stripped effluent pH is increased during steam stripping. This suggests that steam stripping of anaerobically digested manure effluents for ammonia recovery may not need pre-raised pH. In contrast, the pH value of the synthetic ammonia wastewater containing NH4Cl dramatically decreases after steam stripping. Increasing the feed temperature slightly improves ammonia stripping efficiency, but reduces the concentration of the recovered ammonia in the condensate due to an increased condensate volume at a higher feed temperature. Therefore, the feed temperature should be controlled at an optimum point that can compromise the condensate ammonia concentration and the ammonia stripping efficiency. Experimental results indicate that recovery of ammonia from anaerobically digested cattle manure effluents as NH4OH is technically feasible.

Characterization of commercial RO membranes for the concentration of ammonia converted to ammonium sulfate from anaerobic digesters

“…These include, the application of hollow fiber membranes [10], vibrating reverse osmosis membranes [11], absorption [12], and steam stripping [13]. Alternatively, TAN present in digestate could be transformed into a stable form, and then separated.…”

Ammonium and potassium removal for anaerobically digested wastewater using natural clinoptilolite followed by membrane pretreatment

“…The removal and recovery of the residual ammonia will have both significant environmental and economic benefits. It is necessary to employ an ion exchange system to clean the residual ammonia and then the concentrated ammonia from the regeneration solution can be successfully recovered by the steam stripping [3,4]. Natural zeolite clinoptilolite has been broadly investigated as ion exchanger for this purpose due to its high ammoniumion selectivity [5][6][7][8][9].…”

Photocatalytic oxidation of ammonia by cadmium sulfide/titanate nanotubes synthesised by microwave hydrothermal method

“…The different mass recoveries measured at different loading amounts of CdS nanoparticles support the idea that the relative contributions of homogeneous and heterogeneous reactions depend on amount of catalysts (Zhu et al 2005). The initial solution without adding catalysts was a homogeneous reaction that yielded a 71.1% mass recovery, indicating a possible formation of products in gas phase such as N 2 , NH 2 OH, or NH 4 OH (Zeng et al 2006). The mass recoveries of the experiments with CdS photocatalysts were increased up to 80%, indicating CdS photocatalysts were reacted with ammonia solution performing heterogeneous reactions.…”