New Natural Coagulant Aid in Water Treatment

Jenny Siew Lee Chew,Wai Loon Chan,Yeek Chia Ho,Agnes Yin Yee Ho,Jun Wei Lim,Soon Onn Lai,Boon Chin Lim,M Raza Ul Mustafa,I Bin Othman,D Bayu Endrayana,M Latheef,N Zulaikha Bt Yusof

doi:10.1051/matecconf/201820303004

Abstract

Natural source of coagulant is certainly being considered in addressing the disadvantages associated with the use of inorganic coagulants. Annona muricata is hypothesized to be new material as natural coagulant aid in coagulation-flocculation process. On the other hand, due to the high lipids content in microalgae, namely, Chlorella vulgaris is used in producing renewable energy, i.e. biodiesel. Coagulation-flocculation is an effective method in microalgae harvesting. Thus, in this study, a novel natural coagulant aid extracted from fruit waste in algae harvesting. It is aimed to (1) to extract natural coagulant aid (hereafter is known as biopolymer) extracted from Annona muricata seeds in algae harvesting, and (2) to evaluate the operational conditions of coagulation-flocculation process by utilizing the biopolymer. As a result, it is observed that acid extraction and extraction through sodium chloride does not show any yield. On the other hand, the harvesting efficiency showed positive response as coagulant aid at 20 mg/L.

Highlights

The current and most promising harvesting methods include filtration, centrifugation, gravity sedimentation and coagulation-flocculation
Possibility of cell damage due to high shear force may be induced in centrifugation harvesting method
Low biodegradability and high cost are the associated disadvantages due to the usage of organic coagulant such as polyacrylamides whereas the inorganic coagulant, or chemical coagulant can contaminate the microalgae with toxic substances [3]

Summary

Introduction

The current and most promising harvesting methods include filtration, centrifugation, gravity sedimentation and coagulation-flocculation. Each of this method has significant drawback in harvesting microalgae. Regardless of the high efficiency of coagulation-flocculation in microalgae recovery, the utilization of both organic and inorganic coagulants do produce certain drawbacks to the harvested microalgae. Hamid et al [5] and Yang et al [8] demonstrated the high practicability of natural coagulant utilization in microalgae harvesting by claiming that the harvesting efficiency using M. oleifera seed achieved 90% and above, comparing to the application of alum which yield only 34% of microalgae biomass recovery at the same dosage. Where A is OD680 of the sample before treatment; B is OD680 of the sample after treatment

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