Volume 49 Number 3

Application of thermally treated granulated attapulgite for advanced treatment of membrane bioreactor effluent

Na Lv^a,*, Sisi Fan^a,b

 
ABSTRACT:     Thermally treated granulated attapulgite (TGAT) with increased metal ion content and improved internal structure was employed to further improve the effluent quality of membrane bioreactor (MBR), and its effect on the effluent of anoxic/oxic MBR (A/O-MBR) was investigated. The A/O-MBR fixed-bed column reactors were constructed and filled with unmodified granulated attapulgite (GAT) and TGAT, respectively. Under the conditions of membrane effluent total phosphorus and total nitrogen concentrations of 1.24?2.33 and 14.09?17.55 mg/l, respectively, the fixed bed column filled with TGAT showed better nitrogen and phosphorus removal effects, with significantly improved effluent quality, when compared with fixed-bed column filled with GAT. Fourier transform infrared spectroscopy and inductively coupled plasma emission spectroscopy proved that the reduction of hydroxyl structure and increase in metal ions in attapulgite after thermal treatment were more conducive to phosphate capture and biofilm formation. TGAT removed nitrogen and phosphorus pollutants from wastewater predominantly through the action of denitrifying microorganisms and precipitation, respectively. Following extended operation of the reactor, elevated nitrogen and phosphorus levels were noted on the surface and within the filler. Application of the used TGAT adsorbent as fertilizer increased plant height, leaf width, fresh weight, and dry weight by 75.13%, 84.64%, 202.48%, and 204.13%, respectively. Thus, TGAT could be used for the advanced treatment of membrane effluent and applied as a slow-release fertilizer to achieve reuse of resources.

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* Corresponding author, E-mail: lzylvna@163.com

Received 26 Jul 2025, Accepted 2 Jun 2026