Long-term impact of salinity on the performance and microbial population of an aerobic granular reactor treating a high-strength aromatic wastewater

Abstract

The effect of salinity over granular biomass treating a mixture of aromatic compounds (phenol, o-cresol and p-nitrophenol) was evaluated in a continuous airlift reactor. To mimic an industrial wastewater, increasing concentrations (from 2.0 to 29.0 g salts L(-1)) of a mixture of salts (MgSO4, NaCl, KCl, CaCl2 and NaHCO3) were introduced in the influent. The gradual salinity increase led to a good acclimation of the biomass obtaining complete biodegradation of the aromatic compounds and no accumulation of metabolic intermediates. However, a deterioration of the morphology of aerobic granules with a complete loss of granulation after 125 days was produced at 29.0 g salts L(-1). At that moment, anaerobic granules were added to promote granulation and after 50 days new aerobic granules were formed. These new aerobic granules remained stable for more than 100 days at the highest salinity condition with 100% removal of the mixture of aromatic compounds.

Development of Aerobic Granular Sludge for Chemical Industries Wastewater Treatment

“…The size of aerobic granules developed in the present study using MEG is much larger for the similar time frame as compared to the earlier reports on synthetic or real wastewater (15)(16)(17). The literature already includes several reports of selective pressures effecting aerobic granulation.…”

Simultaneous partial nitrification and 2-fluorophenol biodegradation with aerobic granular biomass: Reactor performance and microbial communities

“…The variation of the bacterial community composition probably resulted from the adaptation to the conditions in the living environment namely the influent wastewater composition, the load of the toxic compound and the operational conditions. Nevertheless, the impact of the load of toxic compounds in the bacterial population is well documented in the literature (Amorim et al, 2014;Duque et al, 2015;Ramos et al, 2015).…”

The role of extracellular polymeric substances on aerobic granulation with stepwise increase of salinity

“…Saline wastewaters represent a high amount of sewage produced all over the world, since several industrial sectors, such as agro-food, petrochemical, textile and leather industries, paper-making, chemical manufacturing, pesticides and herbicides industries use water and inorganics salts in the process chain [1]. These effluents contain salts like chlorides, carbonates and sulphates and, often, organic and particularly recalcitrant compounds such as aromatic compounds [2]. The discharge of such wastewater having at the same time high salinity and high organic content without prior treatment, adversely affect the environment.…”