Integrated green membrane distillation-microalgae bioremediation for arsenic removal from Pengorak River Kuantan, Malaysia

Abstract

This study introduces an integrated system of direct contact membrane distillation (DCMD) and microalgae bioremediation for green removal of arsenic from the polluted river water. An inexpensive hydrophobic kaolin hollow fiber membrane (h-KHFM) was fabricated and used in the DCMD process for arsenic treatment on the polluted river water. The membrane demonstrates an excellent arsenic rejection of 100 % and a stable flux of 23.3 kg/m2h throughout the prolonged operation of 70 h. The performance of this membrane was compared with those of NF and RO; the results indicate superior performance of h-KHFM over the latter two processes in terms of permeate flux, arsenic rejection, as well as the performance flexibility and consistency at various pH conditions. The arsenic-rich retentate of the DCMD process is then bioremediated using Botryococcus sp. with an initial cell concentration of 1 × 106 cells/mL at the outdoor conditions. The findings show that Botryococcus sp. successfully grow in the retentate with a common microalgae growth pattern during the 20 days test period, which indicates the potential and feasibility of this integrated system for the arsenic retentate management. This study is pioneer and could provide an insight for the development of wastewater treatment technologies with zero waste discharge.