scholarly journals TESTING OF CHLORELLA/SCENEDESMUS MICROALGAE CONSORTIA FOR REMEDIATION OF WASTEWATER, CO₂ MITIGATION AND ALGAE BIOMASS FEASIBILITY FOR LIPID PRODUCTION

Author(s):  
Judita Koreivienė ◽  
Robertas Valčiukas ◽  
Jūratė Karosienė ◽  
Pranas Baltrėnas

Industry, transport and unsustainable agriculture result in the increased quantity of wastewater, release of nutrients and emission of carbon dioxide that promotes eutrophication of water bodies and global climate change. the application of microalgae for phycoremediation, their biomass use for human needs may increase sustainability and have a positive effect on the regional development. The experiments were carried out in order to establish the feasibility of treating the local municipal wastewater with microalgae consortia and their biomass potential for biofuel production. The results revealed that Chlorella/Scenedesmus consortium eliminated up to 99.7–99.9% of inorganic phosphorus and up to 88.6–96.4% of inorganic nitrogen from the wastewater within three weeks. The ammonium removal was more efficient than that of nitrate. Chlorella algae grew better in diluted, while Scenedesmus – in the concentrated wastewater. The consortium treated wastewater more efficiently than a single species. The maximum biomass (3.04 g/L) of algal consortium was estimated in concentrated wastewater. Algae accumulated 0.65–1.37 g of CO2/L per day in their biomass. Tus, Chlorella/Scenedesmus consortium is a promising tool for nutrients elimination from the local wastewater under the climatic conditions specific to Lithuania. However, none of the two species were able to accumulate lipids under the nitrogen starvation conditions.

2021 ◽  
Author(s):  
Yan Li ◽  
Ethan Wood ◽  
Gergely Kosa ◽  
Bushra Muzamil ◽  
Christian Vogelsang ◽  
...  

Abstract This study demonstrated that the application of filamentous co-culture could be a promising supplementary approach to further purify municipal tertiary wastewater in Nordic country. Initial screening of 25 algae strains across multiple genera revealed that Spirogyra sp. and Klebsormidium sp. were suitable for use as a coculture for phycoremediation of the tertiary effluent from a wastewater treatment plant, and this result was validated in three consecutive outdoor pilot tests at 10–15 oC. In the first two batches of pilot tests, the total prosperous and ammonium were depleted close to zero in 24 hours, while the pH in the wastewater increased from 7 to 9. In the 3rd batch, CO2 was thereby added for pH control. Macronutrients (N and P) were successfully removed from the treated wastewater. The total algae biomass increased 2 to 3 times over 7 days with average algae productivity of 1.68 g m2 d− 1. Meanwhile, the produced algae biomass accumulated notable mineral elements (Ca, Mg, K, Fe and Al) and some heavy metals at levels of g kg− 1 and mg kg− 1, respectively. In light of circular economy concept, the produced biomass could be used for different valorizations based on the analytical analysis. This study provides a new insight of phycoremediation for further purification of municipal treated wastewater, by effectively using filamentous algae coculture. Given a great potential for further optimization and improvement, this proof of concept will benefit to the green transition of wastewater treatment plants in Nordic country.


2016 ◽  
Vol 75 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Meng Jin ◽  
Pascale Champagne ◽  
Geoffrey Hall

Waste stabilization ponds (WSPs), as part of municipal wastewater treatment strategies, can exhibit variability in performance due to climatic conditions. Under elevated temperature and strong solar radiation, algal blooms and subsequent high pH effluents have often been observed. In this study, four substrates (gravel, peat, organic mulch, and topsoil) were evaluated for their ability to attenuate high pH effluents from a WSP. Synthetic wastewater with pH > 9.5, and low organic and nutrient loadings, was used to mimic algal-induced high pH effluents in 72 L rectangular bench-scale superficial constructed wetland configuration reactors. Peat exhibited the highest attenuation ability, where the effluent pH decreased substantially from 10.3 to 7.7, primarily due to its high organic contents. Peat also removed 53.7% of the influent total phosphorus, which could effectively limit algal growth. No statistically significant differences were discovered among gravel, topsoil, and organic mulch in terms of pH attenuation. Topsoil and organic mulch both have a relatively high alkalinity, making them ideal to maintain consistent pH levels. However, naturally high chemical oxygen demand levels in organic mulch raised concerns in the leaching of these compounds into the treated wastewater, making it less appealing for systems with low organic loading.


2003 ◽  
Vol 3 (4) ◽  
pp. 145-152 ◽  
Author(s):  
H. Heinonen-Tanski ◽  
P. Juntunen ◽  
R. Rajala ◽  
E. Haume ◽  
A. Niemelä

Municipal treated wastewater has been tertiary treated in a pilot-scale rapid sand filter. The filtration process was improved by using polyaluminium coagulants. The sand-filtered water was further treated with one or two UV reactors. The quality changes of wastewater were measured with transmittance, total phosphorus, soluble phosphorus, and somatic coliphages, FRNA-coliphages, FC, enterococci and fecal clostridia. Sand filtration alone without coagulants improved slightly some physico-chemical parameters and it had almost no effect on content of microorganisms. If coagulants were used, the filtration was more effective. The reductions were 88-98% for microbial groups and 80% for total phosphorus. The wastewater would meet the requirements for bathing waters (2,000 FC/100 ml, EU, 1976). UV further improved the hygiene level; this type of treated wastewater could be used for unrestricted irrigation (2.2 TC/100 ml, US.EPA 1992). The improvement was better if coagulants were used. The price for tertiary treatment (filtration + UV) would have been 0.036 Euro/m3 according to prices in 2001 in 22 Mm3/a. The investment cost needed for the filtration unit was 0.020 Euro/m3 (6%/15a). Filtration with coagulants is recommended in spite of its costs, since the low transmittance of unfiltered wastewater impairs the efficiency of the UV treatment.


2021 ◽  
Vol 13 (5) ◽  
pp. 2885
Author(s):  
Jinyu Li ◽  
Baozhen Li ◽  
Jinshui Yang

The bio-flocculation ability of UTEX 2341 was studied for the purpose of improving microalgae harvesting efficiency to cut the high cost of biofuel production. The algae cells of UTEX 2341 cultured under heterotrophic and municipal wastewater conditions were found to have better self-flocculation ability, with flocculation rates of 92% and 85% at 2 h, respectively. Moreover, the flocculation rates of 16 freeze-dried microalgae powder samples cultured under different stress conditions were 0~72% with an algae powder dosage of 35 mg L−1. The flocculation efficiency of DIM, DCd1, DT28, and L6S was stable under different pH of 3~9 and temperatures of 15~50 °C. For samples of IM, LCd0.6, LMn2, and LZn2, the flocculation efficiency decreased or increased respectively with increased pH or temperatures. Though the flocculation properties of the eight samples showed wide differences, their flocculant compositions were almost the same with unknown components occupying large proportions. More studies needed to be further carried out to reveal the flocculation mechanisms and analyze the flocculation abilities in practical application, which would be conducive to future large-scale application of the bio-flocculation method and also cost reduction.


Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 931
Author(s):  
Mona Giraud ◽  
Jannis Groh ◽  
Horst H. Gerke ◽  
Nicolas Brüggemann ◽  
Harry Vereecken ◽  
...  

Grasslands are one of the most common biomes in the world with a wide range of ecosystem services. Nevertheless, quantitative data on the change in nitrogen dynamics in extensively managed temperate grasslands caused by a shift from energy- to water-limited climatic conditions have not yet been reported. In this study, we experimentally studied this shift by translocating undisturbed soil monoliths from an energy-limited site (Rollesbroich) to a water-limited site (Selhausen). The soil monoliths were contained in weighable lysimeters and monitored for their water and nitrogen balance in the period between 2012 and 2018. At the water-limited site (Selhausen), annual plant nitrogen uptake decreased due to water stress compared to the energy-limited site (Rollesbroich), while nitrogen uptake was higher at the beginning of the growing period. Possibly because of this lower plant uptake, the lysimeters at the water-limited site showed an increased inorganic nitrogen concentration in the soil solution, indicating a higher net mineralization rate. The N2O gas emissions and nitrogen leaching remained low at both sites. Our findings suggest that in the short term, fertilizer should consequently be applied early in the growing period to increase nitrogen uptake and decrease nitrogen losses. Moreover, a shift from energy-limited to water-limited conditions will have a limited effect on gaseous nitrogen emissions and nitrate concentrations in the groundwater in the grassland type of this study because higher nitrogen concentrations are (over-) compensated by lower leaching rates.


2015 ◽  
Vol 72 (4) ◽  
pp. 579-584 ◽  
Author(s):  
A. Muramatsu ◽  
H. Ito ◽  
A. Sasaki ◽  
A. Kajihara ◽  
T. Watanabe

To achieve enhanced nitrogen removal, we modified a cultivation system with circulated irrigation of treated municipal wastewater by using rice for animal feed instead of human consumption. The performance of this modified system was evaluated through a bench-scale experiment by comparing the direction of circulated irrigation (i.e. passing through paddy soil upward and downward). The modified system achieved more than three times higher nitrogen removal (3.2 g) than the system in which rice for human consumption was cultivated. The removal efficiency was higher than 99.5%, regardless of the direction of circulated irrigation. Nitrogen in the treated municipal wastewater was adsorbed by the rice plant in this cultivation system as effectively as chemical fertilizer used in normal paddy fields. Circulated irrigation increased the nitrogen released to the atmosphere, probably due to enhanced denitrification. Neither the circulation of irrigation water nor its direction affected the growth of the rice plant and the yield and quality of harvested rice. The yield of rice harvested in this system did not reach the target value in normal paddy fields. To increase this yield, a larger amount of treated wastewater should be applied to the system, considering the significant amount of nitrogen released to the atmosphere.


Author(s):  
Nupur Pancholi ◽  
◽  
Sanjit Kumar Mishra ◽  

Drawing on Amitav Ghosh’s novel Gun Island (2019) together with his nonfictional The Great Derangement (2016), the article strives to present that while advancing endless desires, human-centric culture and the idea of ‘good life’ drive climate change and environmental deterioration. It seeks to enumerate the devastating consequences of changing climatic conditions and degenerating ecosystems and their cumulative impacts on the humankind and non-human world. It aims to locate how human life at the margins has been affected by these cataclysmic consequences through analysing Ghosh’s Gun Island. It attempts to show that human interventions had significantly fuelled the global climate crisis in the seventeenth century, decoding the myth of Bonduki Sadagar that Ghosh identifies in Gun Island.


2018 ◽  
Vol 78 (7) ◽  
pp. 1566-1575 ◽  
Author(s):  
S. S. Rathnaweera ◽  
B. Rusten ◽  
K. Korczyk ◽  
B. Helland ◽  
E. Rismyhr

Abstract A pilot-scale CFIC® (continuous flow intermittent cleaning) reactor was run in anoxic conditions to study denitrification of wastewater. The CFIC process has already proven its capabilities for biological oxygen demand removal with a small footprint, less energy consumption and low cost. The present study focused on the applicability for denitrification. Both pre-denitrification (pre-DN) and post-denitrification (post-DN) were tested. A mixture of primary treated wastewater and nitrified wastewater was used for pre-DN and nitrified wastewater with ethanol as a carbon source was used for post-DN. The pre-DN process was carbon limited and removal rates of only 0.16 to 0.74 g NOx-N/m²-d were obtained. With post-DN and an external carbon source, 0.68 to 2.2 g NO3-Neq/m²-d removal rates were obtained. The carrier bed functioned as a good filter for both the larger particles coming with influent water and the bio-solids produced in the reactor. Total suspended solids removal in the reactor varied from 20% to 78% (average 45%) during post-DN testing period and 9% to 70% (average 29%) for pre-DN. The results showed that the forward flow washing improves both the DN function and filtration ability of the reactor.


2013 ◽  
Vol 9 (6) ◽  
pp. 2413-2432 ◽  
Author(s):  
N. R. Nowaczyk ◽  
E. M. Haltia ◽  
D. Ulbricht ◽  
V. Wennrich ◽  
M. A. Sauerbrey ◽  
...  

Abstract. A 318-metre-long sedimentary profile drilled by the International Continental Scientific Drilling Program (ICDP) at Site 5011-1 in Lake El'gygytgyn, Far East Russian Arctic, has been analysed for its sedimentologic response to global climate modes by chronostratigraphic methods. The 12 km wide lake is sited off-centre in an 18 km large crater that was created by the impact of a meteorite 3.58 Ma ago. Since then sediments have been continuously deposited. For establishing their chronology, major reversals of the earth's magnetic field provided initial tie points for the age model, confirming that the impact occurred in the earliest geomagnetic Gauss chron. Various stratigraphic parameters, reflecting redox conditions at the lake floor and climatic conditions in the catchment were tuned synchronously to Northern Hemisphere insolation variations and the marine oxygen isotope stack, respectively. Thus, a robust age model comprising more than 600 tie points could be defined. It could be shown that deposition of sediments in Lake El'gygytgyn occurred in concert with global climatic cycles. The upper ~160 m of sediments represent the past 3.3 Ma, equivalent to sedimentation rates of 4 to 5 cm ka−1, whereas the lower 160 m represent just the first 0.3 Ma after the impact, equivalent to sedimentation rates in the order of 45 cm ka−1. This study also provides orbitally tuned ages for a total of 8 tephras deposited in Lake El'gygytgyn.


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