An Innovative Look into Ammonium Nitrogen Removal Using Algae and Zeolites as an Element of a Circular Bioeconomy

Abstract

This work focused on the potential of simultaneously removing ammonium nitrogen from industrial wastewater using immobilized microalgae and powdered zeolite. Experiments were performed with different species and doses of microalgae embedded in spherical hydrogels in semicontinuous conditions. Ammonium nitrogen uptake by microalgae promoted the slow release of previously adsorbed ammonium nitrogen from zeolite that was then also absorbed by microalgae. Results showed that immobilized microalgae can reach a removal efficiency of up to 60% (C. vulgaris) and 42% (S. armatus). A higher removal efficiency was obtained for zeolites and immobilized C. vulgaris or S. armatus up to 86% and 79%, respectively. Moreover, a higher maximum sorption capacity for C. vulgaris (13.8 mg/g) was achieved than for S. armatus (5.5 mg/g). The recycling of spent hydrogel, zeolite, and wastewater is possible. Such an approach represents a circular bioeconomy loop.

Possibilities of Managing Waste Iron Sorbent FFH after CO2 Capture as an Element of a Circular Economy

“…Recycling processes may include the recovery of iron or other valuable components from sorbents and their reuse in industrial or municipal processes [ 13 , 14 ]. Additionally, it is important that waste (used) sorbents are properly managed to minimize their impact on the environment and public health and to be economically viable [ 15 , 16 ]. This may include controlling emissions of harmful substances, preventing soil and water pollution as well as ensuring the safe disposal of waste [ 17 , 18 , 19 ].…”

“…Biological methods, such as bioleaching or the use of sewage sludge technology, can effectively process sorbents, reducing their toxicity and enabling the recovery of valuable components. This type of approach minimizes waste, reduces the need for primary raw materials and supports sustainable development by closing the life cycle of materials [ 15 , 16 , 17 , 18 , 19 ].…”