Feasibility of Using Microalgal Biomass Cultured in Domestic Wastewater for the Removal of Chromium Pollutants

2008 ◽  
Vol 80 (7) ◽  
pp. 647-653 ◽  
Author(s):  
Xu Han ◽  
Yuk Shan Wong ◽  
Ming Hung Wong ◽  
Nora Fung Yee Tam
Keyword(s):  
Domestic Wastewater ◽  
Microalgal Biomass

scholarly journals Lab-scale assessment and adaptation of wastewater for cultivation of microalgal biomass for biodiesel production

2015 ◽  
Author(s):  
◽  
Luveshan Ramanna
Keyword(s):  
Large Scale ◽  
Physiological Stress ◽  
Lipid Production ◽  
Domestic Wastewater ◽  
Potassium Nitrate ◽  
Wastewater Effluent ◽  
Biodiesel Production ◽  
Available Nitrogen ◽  
Microalgal Biomass ◽  
Microalgal Culture

In light of the world’s declining fossil fuel reserves, the use of microalgal biodiesel has come to the forefront as a potentially viable alternative liquid fuel. The depleting freshwater reserves make the feasibility of this concept questionable. The use of wastewater reduces the requirement for depleting freshwater supplies. This project aimed to determine the viability of municipal domestic wastewater effluent as a substrate for microalgal growth, in order to generate an economical and environmentally friendly source of biofuel. Wastewater effluents from three domestic wastewater treatment plants were characterized in terms of known microalgal nutrients viz., ammonia, phosphate and nitrates. Phosphate concentrations varied throughout the year and were found to be low (< 3 mgL-1) whilst ammonia and nitrate concentrations ranged from 0 to 10 mgL-1 throughout the experimental period. These wastewaters were found to be suitable for cultivating microalgae. The study explored the cultivation of Chlorella sorokiniana on pre- and post-chlorinated domestic wastewater effluent to assess their potential as a medium for high microalgal culture density and lipid production. Post-chlorinated wastewater effluent was found to be superior to pre-chlorinated wastewater effluent, as evident by the higher biomass concentration. This wastewater stream did not contain high concentrations of bacteria when compared to pre-chlorinated wastewater effluent. Nitrogen is an essential nutrient required for regulating the growth and lipid accumulation in microalgae. Cultures growing in post-chlorinated effluent had a lifespan of 18 d. Residual nitrogen in wastewater effluent supported microalgal growth for limited periods. Supplementation using cheap, readily available nitrogen sources was required for optimal biomass and lipid production. Urea, potassium nitrate, sodium nitrate and ammonium nitrate were evaluated in terms of biomass and lipid production of C. sorokiniana. Urea showed the highest biomass yield of 0.216 gL-1 and was selected for further experimentation. Urea concentrations (0–10 gL-1) were assessed for their effect on growth and microalgal physiology using pulse amplitude modulated fluorometry. A concentration of 1.5 gL-1 urea produced 0.218 gL-1 biomass and 61.52 % lipid by relative fluorescence. Physiological stress was evident by the decrease in relative Electron Transport Rate from 10.45 to 6.77 and quantum efficiency of photosystem II charge separation from 0.665 to 0.131. Gas chromatography analysis revealed that C16:0, C18:0, C18:1, C18:2 and C18:3 were the major fatty acids produced by C. sorokiniana. Wastewater effluent has been considered an important resource for economical and sustainable microalgal biomass/lipid production. The study showed that C. sorokiniana was sufficiently robust to be cultivated on wastewater effluent supplemented with urea. The results indicate that supplemented wastewater effluent was an acceptable alternative to conventional media. Using a relatively cheap nitrogen source like urea can certainly improve the techno-economics of large scale biodiesel production.

scholarly journals Evaluating the sustainability of waste substrates for microalgal biomass production using different modes of cultivation

2018 ◽  
Author(s):  
◽  
Prathana Ramsundar
Keyword(s):  
Wastewater Treatment ◽  
Biomass Production ◽  
Bacterial Load ◽  
Biomass Productivity ◽  
Domestic Wastewater ◽  
Microalgal Biomass ◽  
Domestic Wastewater Treatment ◽  
Cultivation Strategy ◽  
Production Strategy ◽  
Pre Treatment

The utilization of wastewater as a substrate for microalgal biomass cultivation is one of the few potentially viable routes for fuel and feed applications. In this study, the suitability of various liquid wastewater streams and waste biosolids from a domestic wastewater treatment plant was assessed for microalgal cultivation. The wastewater substrates were analyzed for nutrient content as a potential growth medium. For liquid waste substrates, physical, thermal and biological pre-treatment methods were evaluated to minimize the bacterial load. Biomass, physiology, nutrient removal efficiencies and biochemical constituents of Chlorella sorokiniana were investigated in influent (INF) and anaerobic tank centrate (AC) under mixotrophic (Mixo) and heterotrophic (Hetero) cultivation modes. Mixotrophic cultivation conditions demonstrated efficient ammonium (94.29%) and phosphate (83.30%) removal with promising biomass (77.14 mgL-1d-1), lipid (24.91 mgL-1d-1), protein (22.36 mgL-1d-1) and carbohydrate (20.10 mgL-1d-1) productivities. Urea supplementation (1500 mgL-1) further enhanced biomass (162.50 mgL-1d-1), lipid (24.91 mgL-1d-1), protein (22.36 mgL-1d-1) and carbohydrate (20.10 mgL-1d-1) productivities in Mixo AC. Therefore, the urea supplemented Mixo AC approach for microalgal cultivation was developed as a suitable biomass production strategy. This work also elucidated a novel algae cultivation strategy for utilisation of waste biosolids, where nutrient-rich waste activated sludge (WAS) and final effluent (FE) from the wastewater treatment process was used for microalgal biomass generation. This strategy reduced the use of synthetic nutrients, fertilizers and freshwater which contribute significantly towards the overall cost of biomass production. Strategy development included the investigation of physical, thermal and chemical pre-treatment methods to assist in effective nutrient release and bacterial load reduction. Evaluation of growth kinetics, photosynthetic performance, nutrient removal efficiencies and biochemical composition of microalgae under mixotrophic and heterotrophic modes of cultivation were performed. Furthermore, urea supplementation was studied to improve biomass productivity. Microalgae cultivation in acid pre-treated (pH 2) WAS + FE with urea supplementation (1500 mgL-1) showed enhanced biomass productivity of 298.75 mgL-1d-1. Microalgal biomass grown with WAS + FE using the developed strategy exhibited greater lipid (72.95 mgL-1d-1) and protein (72.84 mgL-1d-1) productivities and comparable carbohydrate yields (73.07 mgL-1d-1) to that of synthetic media. Thus mixotrophic mode of cultivation coupled with urea supplementation to WAS + FE proved to be a suitable cultivation strategy for C. sorokiniana. The study developed an efficient strategy to utilize AC and WAS + FE as a growth medium for microalgae. Furthermore, findings from this study have demonstrated the potential of waste streams and waste solids from domestic wastewater treatment plants for microalgal biomass generation

scholarly journals Surfactant removal and biomass production in a microalgal-bacterial process: effect of feeding regime

2020 ◽  
Vol 82 (6) ◽  
pp. 1176-1183 ◽  
Author(s):  
Mayara L. Serejo ◽  
Sarah L. Farias ◽  
Graziele Ruas ◽  
Paula L. Paulo ◽  
Marc A. Boncz
Keyword(s):  
Biomass Production ◽  
Nutrient Removal ◽  
Domestic Wastewater ◽  
High Rate ◽  
Organic Load ◽  
Microalgal Biomass ◽  
Feeding Regime ◽  
Treated Effluent ◽  
Domestic Wastewater Treatment ◽  
Continuous Feeding

Abstract The influence of the feeding regime on surfactant and nutrient removal and biomass production was evaluated in three high rate algal ponds for primary domestic wastewater treatment. Feeding times of 24, 12 and 0.1 h d−1 were studied in each reactor at a similar hydraulic retention time of 7.0 days and organic load of 2.3 mg m−2 d−1. Semi-continuous feeding at 12 and 0.1 h d−1 showed better microalgal biomass production (0.21–0.23 g L−1) and nutrient removal, including nitrogen (74–76%) and phosphorus (80–86%), when compared to biomass production (0.13 g L−1) and nitrogen (69%) and phosphorus (46%) removals obtained at continuous feeding (24 h d−1). Additionally, the removal efficiency of surfactant in the three reactors ranged between 90 and 97%, where the best result was obtained at 0.1 h d−1, resulting in surfactant concentrations in the treated effluent (0.3 mg L−1) below the maximum freshwater discharge limits.

AN APPROACH ON ATTACHED GROWTH PROCESS FOR DOMESTIC WASTEWATER TREATMENT

2014 ◽  
Vol 13 (1) ◽  
pp. 145-152 ◽  
Author(s):  
Alireza Valipour ◽  
Seyed Masoud Taghvaei ◽  
Venkatraman Kalyan Raman ◽  
Gagik Badalians Gholikandi ◽  
Shervin Jamshidi ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Growth Process ◽  
Domestic Wastewater ◽  
Attached Growth ◽  
Domestic Wastewater Treatment

Pilot Plant Study on Microaerobic Self-Granulated Sludge Process (Multi-Stage Reversing Flow Bioreactor: MRB)

1991 ◽  
Vol 23 (4-6) ◽  
pp. 973-980 ◽  
Author(s):  
M. Takahashi ◽  
S. Kyosai
Keyword(s):  
Pilot Plant ◽  
High Performance ◽  
Anaerobic Bacteria ◽  
Domestic Wastewater ◽  
Public Works ◽  
Symbiotic Interaction ◽  
Sulfate Reducing ◽  
Pellet Formation ◽  
Multi Stage ◽  
Domestic Wastewater Treatment

A Multi-stage Reversing flow Bioreactor (MRB) was developed by the Public Works Research Institute in 1986. It utilizes the symbiotic interaction between anaerobic bacteria (sulfate reducing bacteria) and microaerobic bacteria (Beggiatoa=filamentous sulfur oxidizing bacteria) for self-granulated pellet formation. A MRB Pilot plant for domestic wastewater treatment (design capacity was 225 m3/day) was constructed in 1988. After several modifications of the initial design, stable pellet formation and high performance were achieved. This paper describes the results of the pilot plant operation.

Basic Studies on Phosphorus Removal by the Contact Aeration Process Using Iron Contactors

1991 ◽  
Vol 23 (4-6) ◽  
pp. 641-650 ◽  
Author(s):  
S. Haruta ◽  
T. Takahashi ◽  
T. Nishiguchi
Keyword(s):  
Corrosion Rate ◽  
Phosphorus Removal ◽  
Domestic Wastewater ◽  
Small Scale ◽  
Combined Method ◽  
Sulfate Reducing ◽  
Biological Sludge ◽  
Aeration Process ◽  
Basic Studies ◽  
Volumetric Loading

The authors have developed what we call the submerged iron contactor process as a simple and inexpensive phosphorus removal method for small-scale plants disposing of domestic wastewater and household wastewater treatment tanks. In this method iron contactors are submerged in biological treatment tanks, where phosphate anions in wastewater are combined with iron cations produced through corrosion of the contactors, and the compound thus produced is precipitated and removed together with biological sludge. In these studies, laboratory experiments were made on the contact aeration process combined with the above-mentioned method, and the following findings were obtained. (1) It is desirable to treat wastewater by making use of corrosion by sulfate-reducing bacteria instead of corrosion by oxygen dissolved in wastewater, to conduct a stable phosphorus removal by this combined method. (2) The corrosion rate of iron contactors is affected by the volumetric loading of BOD in the tanks where they are submerged. (3) Assuming that an iron contactor continues to suffer corrosion evenly all over the surface when our combined method is applied, it is estimated that the corrosion rate is about 1mm or less in 30 years.

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