Publication: Nutrients recovery from freshwater aquaculture effluent via zeolite assisted forward osmosis
Loading...
Date
2024-08-01
Authors
Aaron, Koe Zhen Yao
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The increased generation of inland aquaculture effluent gives rise to the
importance of nutrient recovery from said effluents. Freshwater fish farm effluent
consists of dilute nutrients, such as ammonium, NH4
+ and phosphate, PO4
3- ions. The
treatment of aquaculture effluent is crucial as irresponsible discharge of them will
cause ecological imbalances, such as eutrophication and hyper nitrification. The
complex nature of aquaculture effluent and its trace content are the obstacle for
nutrient recovery due to the presence of various cations in the wastewater. This study
demonstrated the potential of PO4
3- recovery via chemical precipitation by using a
forward osmosis (FO) process system with the assistance of zeolite. NH4
+ recovery
was also conducted via zeolite regeneration. Preliminary studies of FO operations
concluded that NH4
+ transport across membrane layer is dependent on self-diffusion
flux and diffusion flux induced by reverse Mg2+ flux while PO4
3- flux was mainly
contributed by convective flux. Although membrane orientation with active layer
facing draw side exhibited higher water flux, the rejections of NH4
+ showed similar
values with FO mode. Preliminary studies showed that the two-step Mg-zeolite Y
sorption process successfully supplied Mg2+ into the feed solution and improved the
NH4
+ rejection for the FO process while exhibiting zero sorption capacity for PO4
3-
.
The overall rejection for NH4
+ and PO4
3- for seawater driven zeolite-assisted FO
process remained relatively high at 94.8% and 98.6%, respectively. PO4
3- recovery
studies concluded that concentrated solution from zeolite-assisted FO process (Mg rich solution) with solution pH at 10.5 showed the optimum precipitation results. The
results obtained were 98.46% PO4
3- recovery, 0.51 g of solid/L of solution, and