Optimization of Temperature and Inoculum Size for Phycoremediation of Paddy-Soaked Rice Mill Wastewater
01 Jan 2020-Journal of Environmental Engineering (American Society of Civil Engineers (ASCE))-Vol. 146, Iss: 1, pp 04019091
TL;DR: In this article, microalgae is used as a sustainable treatment system by integrating the wastewater treatment with bioenergy recovery, transforming this technology to real-time, but it is difficult to implement in practice.
Abstract: Phycoremediation encompasses microalgae as a sustainable treatment system by integrating the wastewater treatment with bioenergy recovery. However, transforming this technology to real time...
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TL;DR: In this article, the selected microalgae (Chlorella pyrenoidosa) was cultured in paddy-soaked wastewater (PWW) using outdoor raceway ponds of 50 L capacity where biotransformation of nutrients (NH3−N removal: 75.89±−0.69); PO4−P removal: 73.71±− 0.75%; yield co-efficient YN: 6.56−±-0.
Abstract: Sustainable resources management, incorporating energy markets and resources such as electricity, fossil fuels, renewable and sustainable energy capital is essential for society to understand production and conversion of various forms of energy, their current as well as future supply. Waste-to-energy (WTE) or energy-from-waste (EFW) is a well-identified transitional technology which could prevent complete depletion of renewable resources. In our present study, the selected microalgae (Chlorella pyrenoidosa) was cultured in paddy-soaked wastewater (PWW) using outdoor raceway ponds of 50 L capacity where biotransformation of nutrients (NH3–N removal: 75.89 ± 0.69%; PO4–P removal: 73.71 ± 0.75%; yield co-efficient YN: 6.12 mg biomass/mg of N; YP: 7.77 mg biomass/mg P) has occurred with better growth and biochemical composition (dry biomass weight: 1.56 ± 0.11 g/L; chlorophyll: 15.57 ± 0.14 mg/L; specific growth rate (SGR): 0.42/d; lipids: 27.47 ± 1.41% biomass; carbohydrates: 23.77 ± 1.00% and protein: 46.12 ± 3.55%). Further, the obtained algal lipid was identified for a wide range of fatty acid methyl esters (FAME) and consequently brought forward to in-situ single-step transesterification by optimizing reaction conditions. Central composite design (CCD) of response surface methodology (RSM) has given optimized conditions of sample amount: 2 g (wet); methanol sulphuric acid volume: 3 mL; and hexane volume: 4 mL, under the reaction temperature of 90 °C for maximum biodiesel conversion (46.54% of algal lipids). The outcome of our current research may add value to the application and development of WTE technology for sustainable energy conservation.
14 citations
01 Feb 2021
TL;DR: The results demonstrate the potential of CO2 and HCO3 −1 in control the CCM pathways, thus, another step in the development of the photobioreactor design.
Abstract: A step to net-zero of carbon dioxide losses in the microalgae cultivation process was targeted in the current study. This research was carried out by using pre-dissolved inorganic carbon (DIC) as a source of carbon with two doses of twenty-five and fifty millilitres. C. sorokiniana MH923013, Coelastrella MH923011 and Coelastrella MH923012 strains were used in the present investigation. The experimental data emphasized the direct influence of carbonic solution on microalgal growth according to the fast adaption of algal cells and higher productivity compared to control and dilution cultures. It was observed that microalgae strains conduct a corresponding response associated with different dosing of the saturated carbonic solution. For instance, dosing of 50 ml carbon dioxide revealed fast performance to reach the stationary phase (23-25) day with clear growth improvement. In addition, 0.1633 day−1 as a maximum specific growth rate in the exponential phase was recorded with this dosing. While as there was another obvious growth enhancement with supplying 25 ml CO2 solution, but reached the stable phase after around (37-42) day from inoculation with a maximum specific growth rate 0.0987 day−1. These results demonstrate the potential of CO2 and HCO3 −1 in control the CCM pathways, thus, another step in the development of the photobioreactor design.
2 citations
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TL;DR: The results provide new eridence that the maximum growth rates of microalgae may be limited by enzymatic processes associated with the assimilation of NO3−, or urea.
Abstract: We examined the energetic dependency of the biochemical and physiological responses of Thalassiosira pseudonana Hasle and Heimdal. Chaetoceros gracilis Schutt, Dunaliella tertiolecta Butcher, and Gymnodinium sanguineum Hirasaka to NH4+, NO3−, and urea by growing them at subsaturating and saturating photon flux (PF). At subsaturating PF, when energy was limiting, NO3− and NH4+ grown cells had similar growth rates and C and X quotas. Therefore, NO3− grown cells used up to 48% more energy than NH4+ grown cells to assimilate carbon and nitrogen. Based on our measurements of pigments, chlorophyll-a-specific in vivo absorption cross-section, and fluorescence-chlorophyll a−1, we suggest that NO3−, grown cells do not compensate for the greater energy requirements of NO3− reduction by trapping more light energy. At saturating PF, when energy is not limiting, the utilization of NO3−, compared to NH4+ resulted in lower growth rates and N quotas in Thalassiosira pseudonana and lower N quotas in Chaetoceros gracilis, suggesting enzymatic rather than energetic limitations to growth. The utilization of urea compared to Nh4+ resulted in lower growth rates in Chaetoceros gracilis and Gymnodinium sanguineum (saturating PF) and in lower N quotas in all species tested at both subsaturating and saturating PF. The high C:N ratios observed in all urea-grown species suggest that nitrogen assimilation may be limited by urea uptake or deamination and that symptoms of N limitation in microalgae may be induced by the nature of the N source in addition to the N supply rate. Our results provide new eridence that the maximum growth rates of microalgae may be limited by enzymatic processes associated with the assimilation of NO3−, or urea.
259 citations
TL;DR: More effective treatment of rice mill wastewater and higher energy recovery was demonstrated by earthen pot MFC as compared to MFC incorporated with PEM.
253 citations
TL;DR: This study has reviewed the status of TWW as potential source of water and nutrients, role of different algal species in the bioremediation of TwW, different cultivation systems, harvesting and biodiesel production methods, and suggests future research and development challenges for coupled textile wastewater treatment and microalgal biodieselproduction.
Abstract: Microalgal biodiesel has emerged as an environment friendly alternative to the existing fossil fuels. The commercial production of this biodiesel is still challenging due to several technical and economic issues, which span from mass cultivation of microalgae to the biodiesel production. Mass cultivation is the most critical step in terms of water and nutrient requirement. Industrial wastewater such as textile wastewater (TWW) is a cheap source for water, which additionally contains necessary nutrients (phosphate, nitrates, micronutrients etc.) and organic dyes (potential carbon source) for algae cultivation. The application of microalgae for biodiesel production employing single objective strategy is not sustainable. Microalgae can be effectively employed to bioremediate TWW (dyes and nutrients removal) and to produce biodiesel from grown microalgae. This process integration (bioremediation-biodiesel production) can potentially improve biodiesel production and wastewater treatment. However, this process coupling needs to be thoroughly investigated to identify and optimize critical process factors (algal species, cultivation and harvesting methods, bioremediation mechanism etc.). This study has reviewed the status of TWW as potential source of water and nutrients, role of different algal species in the bioremediation of TWW, different cultivation systems, harvesting and biodiesel production methods. This review also suggests future research and development challenges for coupled textile wastewater treatment and microalgal biodiesel production.
196 citations
TL;DR: Results show that the most adequate conditions for cultivating So in this effluent are the aerated cultures, exposed to a 12h period of daily light, at 12000 Lux intensity.
185 citations
TL;DR: Algal strain C. pyrenoidosa is not only an agent for mitigation of pollutant load, but it can also be used as potential agent for biofuel production.
184 citations