Ammonia recovery from air stripping process applied to landfill leachate treatment.

The leachate is a type of effluent from landfills containing high concentrations of ammonia, even after normal treatment procedures are applied. Due to its characteristic, the leachate can adversely impact the environment and public health. Leachate treatment seeks to remove a series of compounds with adverse characteristics present in this type of effluent. Ammonia nitrogen is the main problem, easily observed in concentrations near 2000 mg/L. The effluents with high concentrations of ammonia nitrogen can stimulate the growth of algae, reduce the dissolved oxygen in rivers, and cause toxicity on the aquatic biota, even in low concentrations. Many research for treatment methods aiming to remove this compound, specifically, have been increasingly deeper, mainly by physical-chemical processes. This study aimed to test the process of air stripping in a closed system and pilot scale, applied on leachate treatment of landfills, to remove the high concentrations of ammonia nitrogen and its recovery by the chemical absorption of ammonia on phosphoric acid, resulting in a product with potential application as agricultural fertilizer, the ammonia phosphate. The leachate flows used were 9, 18, 20, and 40 L/h, and the air flows were 1800 and 3600 L/h. Calcium carbonate (standard grade), commercial hydrated lime (CHL), and sodium hydroxide (standard grade) were used for pH adjustments. To the ammonia recovery, three flasks were used with 2.5 L of a phosphoric acid solution of 0.12 and 0.24 mol/L. The air stripping tower removed an average of 98% of ammoniacal nitrogen, with an operating time of 4 to 9 days. The volume of air consumed to remove 1 g of ammoniacal nitrogen varied from 9, 91, and 21.6 m3. The ammonia recovery was about 92% using a phosphoric acid solution, producing the ammonia phosphate.

Bioethanol Production From Hydrolyzed Lignocellulosic After Detoxification Via Adsorption With Activated Carbon and Dried Air Stripping.

Bioethanol production has been presented as an alternative for supplying energy demand and minimizing greenhouse gases effects. However, due to abrasively conditions employed on the biomass during pretreatment and hydrolysis processes, inhibitors for fermentation phase such as acetic acid and others can be generated. Based on this problem, the aim of this work was to evaluate the adsorption of acetic acid on microporous activated carbon and investigate the stripping of the same component with dried air. For adsorption process, three concentrations of acetic acid (5, 10, and 20%) were analyzed by adsorption kinetics and adsorption isotherms (Langmuir and Freundlich models). Pseudo-second order model showed to fit better when compared to Pseudo-first order model. The Intraparticle Diffusion model presented the first phase of the adsorption as the regulating step of the adsorption process. The Langmuir model showed the best fitting, and the maximum capacity of adsorption was found as 128.66 mg.g-1. For stripping procedure an apparatus was set in order to insert dried air by a diffusor within the solution in study. Increasing temperature showed to be determinant on augmenting acetic acid evaporation in 2.14 and 6.22 times for 40 and 60°C when comparing it to 20°C. The application of the pickling process for removal of fermentation inhibitors in sugarcane bagasse hydrolyzed allowed the production 8.3 g.L-1 of ethanol.

Pilot aerobic membrane bioreactor and nanofiltration for municipal landfill leachate treatment.

The purpose of this article is to evaluate the integration of the air stripping, membrane bioreactor (MBR) and nanofiltration (NF) processes for the treatment of landfill leachate (LFL). Pretreatment by air stripping, without adjustment of pH, removed 65% of N-NH3 present in LFL. After pretreatment, the effluent was treated in MBR obtaining 44% of COD removal, and part of the N-NH3 was converted to nitrite and nitrate, which was later removed in the post-treatment. Nanofiltration was shown to be an effective process to improve the removal of organic compounds, the high toxicity present in LFL and nitrite and nitrate generated in the MBR. The system (air stripping + MBR + nanofiltration) obtained great efficiency of removal in most parameters analyzed, with overall removal of COD, ammonia, color and toxicity approximately 88, 95, 100 and 100%, respectively. By this route, treated landfill leachate may be reused at the landfill as water for dust arrestment and also as earth work on construction sites.

Remoção dos compostos odoríferos geosmina e 2-metilisoborneol de águas de abastecimento através de processos de aeração em cascata, dessorção por ar e nanofiltração / Removal of the odoriferous compounds geosmin and 2-methylisoborneol from drinking water by the processes of cascade aeration, air strippingand nanofiltration

Atividades humanas aceleram o processo natural de eutrofização das águas, favorecendo a floração de algas e cianobactérias. Estes organismos emitem os compostos 2-metilisoborneol (MIB) e geosmina, que conferem gosto e odor de mofo e terra à água. A presença destes compostos se estende à água potável uma vez que os processos convencionais de tratamento são insuficientes para removê-los. Esta pesquisa foi realizada com o objetivo de avaliar alternativas de processos de tratamento para a remoção de MIB e geosmina da água. Os processos estudados foram aeração em cascata, dessorção por ar e nanofiltração. Os resultados sugerem a possibilidade de remoção quase total de MIB e geosmina da água através do sistema de nanofiltração, enquanto que os processos baseados em aeração e dessorção foram relativamente ineficientes.

Human activities accelerate the natural process of eutrophication, favouring the occurrence of algae and cyanobacterial blooms. These organisms emit the compounds 2-methylisoborneol (MIB) and geosmin, which confer earthy and moldy taste and odor to water. The presence of MIB and geosmin is extended to drinking water inasmuch they are not completely removed by the processes used in conventional treatment. This research was conducted to evaluate the capability of alternative treatment processes to remove MIB and geosmin from water. The processes studied were cascade aeration, air stripping, and nanofiltration. The results suggested that MIB and geosmin can be almost completely removed by nanofiltration, while the processes based on aeration and stripping were relatively inefficient.