%L scholars13323
%J Advances in Environmental Research. Volume 71
%O cited By 0
%D 2020
%X Microalgae are unicellular microorganisms that intrinsically entail carbon dioxide (COinf2/inf), water and nutrients to undergo photosynthesis process and subsequently grow. In general, there are two main groups of factors influencing the growth of microalgae, viz., abiotic and biotic factors. The abiotic factors include the light intensity, pH of cultivation medium, concentration of dissolved COinf2/inf and its derivative species and concentration of nutrients, preponderantly nitrogen and phosphorus containing compounds. On the other hand, the biotic factors are the presence of pathogens or other microalgal species in the same cultivation medium, resulting in the untoward competition in gaining similar rudimentary needs for growth. Among these factors, the concentration of nutrients is the most essential factor manoeuvring the growth of microalgae. Thus, in order to curtail the cost of nutrients employed to grow microalgae, the wastewaters containing nutrients have been recently exploited to replace the commercial nutrients for cultivating microalgae. However, the composition of wastewaters tends to change along with the time, i.e., its nutrients concentrations are varying from one batch to another. Also, the wastewater sources of origins will influence its compositions, e.g., the anaerobically digested wastewater, agricultural wastewater, industrial wastewater, municipal wastewater, etc. are possessing diverse compositional characteristics. Owing to the low cost, simplicity and capability to restore the gigantic holes of landscape resulted from the indiscriminate mining works, landfilling is the most common urban method applied for the disposal of solid wastes. Inevitably, the consequential produced landfill leachate is also rich in various micro- and macro-nutrients. Therefore, the landfill leachate could be used to grow microalgae in tandem with the decomposition of organic matters in leachate, while producing valuable microalgal biomass for various industries inclusive of biofuel businesses. Alas, the landfill leachate is typically loaded with toxic xenobiotic organic compounds (XOCs) and various heavy metals that could be potentially deleterious. Thus, an intensive leachate treatment is crucial to mitigate its hazardous effect from afflicting the quality of human lives and welfare of animals. Nevertheless, the conventional biological or physiochemical treatment, or a combination of both, for treating landfill leachate is frequently insufficient to satisfy the discharged limits as decreed by the local authority. In this regard, the pre-treatment of landfill leachate via ultra-sonication was explored to debilitate its inhibitory effect prior to the later bioremediation by microalgae. Accordingly, the by-products generated from ultrasonic pre-treatment were assimilated by microalgae for growth. It was noticed that the longer the duration of ultrasonic pretreatment, the higher the removal efficiency of ammoniacal nitrogen by microalgae was eventually recorded. Also, the removal efficiency of ammoniacal nitrogen by microalgae increased with the increase of power input during the ultrasonic pre-treatment. The microalgal biomasses were as well observed increasing during the increases of duration and power input of ultrasonic pre-treatment. In conclusion, the ultrasonic pretreatment of landfill leachate was found to be a necessary procedure in order to assimilate the nutrients from leachate for growing microalgal biomass, sustaining the microalgal feedstock production while bioremediating the landfill leachate simultaneously. © 2020 Nova Science Publishers, Inc. All rights reserved.
%P 69-93
%I Nova Science Publishers, Inc.
%A W.H. Leong
%A C.Y. Leong
%A J.W. Lim
%A N.A. Ghani
%A D.L. Chuan Ching
%A Y.C. Ho
%A M.K. Lam
%A P.S. Goh
%A E.A. Kadir
%T Landfill leachate medium employed for growing microalgal biomass: A combined mini-review and experimental works