Effects of operation parameters on nutrient removal from wastewater and high-protein biomass production in a duckweed-based (Lemma aequinoctialis) pilot-scale system

The effects of water depth, coverage rate and harvest regime on nutrient removal from wastewater and high-protein biomass production were assessed in a duckweed-based (Lemna aequinoctialis) pilot-scale wastewater treatment system (10 basins × 12 m2) that is located near Dianchi Lake in China. The results indicated that a water depth of 50 cm, a coverage rate of 150% and a harvest regime of 4 days were preferable conditions, under which excellent records of high-protein duckweed (dry matter production of 6.65 g/m2/d with crude protein content of 36.16% and phosphorus content of 1.46%) were obtained at a temperature of 12–21 °C. At the same time, the system achieved a removal efficiency of 66.16, 23.1, 48.3 and 76.52% for NH4+-N, TN, TP and turbidity, respectively, with the considerable removal rate of 0.465 g/m2/d for TN and 0.134 g/m2/d for TP at a hydraulic retention time of 6 days. In additionally, it was found that a lower duckweed density could lead to higher dissolved oxygen in the water and then a higher removal percentage of NH4+-N by nitrobacteria. This study obtains the preferable operation conditions for wastewater treatment and high-protein biomass production in a duckweed-based pilot-scale system, supplying an important reference for further large-scale applications of duckweed.

Download Full-text

Effect of Different Influent Conditions on Biomass Production and Nutrient Removal by Aeration Microalgae Membrane Bioreactor (ICFB-MMBR) System for Mariculture Wastewater Treatment

Membranes ◽

10.3390/membranes11110874 ◽

2021 ◽

Vol 11 (11) ◽

pp. 874

Author(s):

Yi Ding ◽

Shiyuan Wang ◽

Hang Ma ◽

Binyu Ma ◽

Zhansheng Guo ◽

...

Keyword(s):

Growth Rate ◽

Wastewater Treatment ◽

Removal Efficiency ◽

Biomass Production ◽

Nutrient Removal ◽

Membrane Bioreactor ◽

Removal Rate ◽

Pollutant Removal ◽

Average Growth ◽

Pollutant Removal Rate

The nutrient removal and biomass production of the internal circulating fluidized bed microalgae membrane bioreactor (ICFB-MMBR) was studied under different cultivation modes, influent TOC, influent pH, and influent N/P. Platymonas helgolandica tsingtaoensis was used as the biological source. The growth of P. helgolandica tsingtaoensis and the removal efficiency of pollutants in the mixotrophy culture mode were improved compared with other culture modes. With the increased influent TOC, the average growth rate of P. helgolandica tsingtaoensis increased, and ammonia nitrogen and total phosphorus removal rate were improved. The P. helgolandica tsingtaoensis growth rate and nutrient removal efficiencies at the influent pH of 8 were the best among the different influent pH values. As the influent N/P ratio increased from 5 to 20, the P. helgolandica tsingtaoensis growth rate and pollutant removal rate increased gradually. When the influent N/P ratio was higher than 20, the P. helgolandica tsingtaoensis growth rate and pollutant removal rate tended to be stable and did not significantly change with the increase of influent N/P ratio. At the proper influent conditions, the high P. helgolandica tsingtaoensis biomass and nutrient removal efficiency could be obtained in the microalgae membrane bioreactor, which could provide a theoretical basis for the application of the system for wastewater treatment.

Download Full-text

High nutrient removal rate from swine wastes and protein biomass production by full-scale duckweed ponds

Bioresource Technology ◽

10.1016/j.biortech.2012.02.083 ◽

2012 ◽

Vol 112 ◽

pp. 98-104 ◽

Cited By ~ 76

Author(s):

Rodrigo A. Mohedano ◽

Rejane H.R. Costa ◽

Flávia A. Tavares ◽

Paulo Belli Filho

Keyword(s):

Biomass Production ◽

Nutrient Removal ◽

Removal Rate ◽

Full Scale ◽

High Nutrient ◽

Nutrient Removal Rate

Download Full-text

Assessment of Synechococcus elongatus PCC 7942 as an option for sustainable wastewater treatment

Water Science & Technology ◽

10.2166/wst.2021.319 ◽

2021 ◽

Author(s):

Georgios Samiotis ◽

Kostas Stamatakis ◽

Elisavet Amanatidou

Keyword(s):

Wastewater Treatment ◽

Nutrient Removal ◽

Industrial Wastewater ◽

Removal Rate ◽

Synechococcus Elongatus ◽

Green Energy ◽

Dairy Wastewater ◽

Biological Nutrient Removal ◽

Synechococcus Elongatus Pcc 7942 ◽

Pcc 7942

Abstract Industrial wastewaters are recognized as a valuable resource, however their disposal without proper treatment can result in environmental deterioration. The associated environmental/operational cost of wastewater treatment necessitates upgrade of applied processes towards the goals of sustainability and mitigation of climate change. The implementation of cyanobacteria-based processes can contribute to these goals via resources recovery, production of high-value products, carbon fixation and green-energy production. The present study evaluates the cyanobacterium Synechococcus elongatus PCC 7942 (S7942) as a biological component for novel and sustainable alternatives to typical biological nutrient removal processes. Valuable results regarding cultivation temperature boundaries, applied disinfection techniques and analytical methods, as well as regarding relations between parameters expressing S7942 biomass concentration are presented. The results show that at typical industrial wastewater temperatures, S7942 efficiently grew and removed nitrates from treated snack-industry's wastewater. Moreover, in cultures with treated and relatively saline dairy wastewater, its growth rate slightly decreased, but nevertheless nitrates removal rate remained efficiently high. A comparison between typical denitrification processes and the proposed nutrient removal process indicated that a S7942-based system may constitute an alternative or a supplementary to denitrification process. Thus, Synechococcus elongatus PCC 7942 proved to be a potent candidate towards sustainable industrial wastewater treatment applications.

Download Full-text

Oxidation-reduction potential (ORP) regulation of nutrient removal in activated sludge wastewater treatment plants

Water Science & Technology ◽

10.2166/wst.2002.0452 ◽

2002 ◽

Vol 46 (1-2) ◽

pp. 35-39 ◽

Cited By ~ 12

Author(s):

B. Li ◽

P. Bishop

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Nutrient Removal ◽

Wastewater Treatment Plants ◽

Pilot Scale ◽

Redox Status ◽

Organic Substrate ◽

Microbial Biodegradation ◽

Scale Experiment ◽

One Year

Redox potential (ORP) regulation of nutrient removal in aeration tanks was tested for one year in three activated sludge wastewater treatment plants in Cincinnati, OH. The experiment results show a good relationship between ORP values and nutrient removal. Macro-biodegradation and sorption of substrate by activated sludge can significantly increase wastewater ORP, indicating the improvement of redox status of the bulk liquor. DO higher than 1.0 mg/L is necessary for good biodegradation and the improvement of liquid redox status. ORP values at higher temperatures (Twater=20–26°C) were lower than ORP values at lower temperatures (Twater=14–19°C), caused by the lower oxygen saturation capacity in wastewater and the more rapid oxygen consumption by microorganism under warmer conditions. Nitrification occurred at higher ORP values (380 mV) than did organic substrate oxidation (250mV). This verifies that different metabolic processes dominate in different ORP ranges. The pilot-scale experiment results demonstrate that the wastewater ORP values continued to increase throughout the whole 6-hour cycle when the influent COD was higher than 1,000 mg/L. For influent with low COD (40–120 mg/L), the wastewater ORP values did not increase in the second 3 hours of the cycle, during which time the microbial-biodegradation within the activated sludge floc dominated. High DO concentrations (6–8 mg/L) did not help improve the redox status. In fully-aerated wastewater, oxygen deeply penetrated into the activated sludge flocs, and microorganisms biodegraded the substrates within the flocs. Endogenous metabolism predominated.

Download Full-text

Viability assessment of algal wastewater treatment projects under outdoor conditions based on algal productivity and nutrient removal rate

Renewable and Sustainable Energy Reviews ◽

10.1016/j.rser.2021.111435 ◽

2021 ◽

Vol 150 ◽

pp. 111435

Author(s):

José M. Vindel ◽

Estrella Trincado

Keyword(s):

Wastewater Treatment ◽

Nutrient Removal ◽

Removal Rate ◽

Viability Assessment ◽

Algal Productivity ◽

Nutrient Removal Rate

Download Full-text

Bacterial removal in three pilot-scale wastewater treatment systems for rural areas

Water Science & Technology ◽

10.2166/wst.1997.0733 ◽

1997 ◽

Vol 35 (11-12) ◽

pp. 197-200 ◽

Cited By ~ 9

Author(s):

M. Garcia ◽

E. Bécares

Keyword(s):

Wastewater Treatment ◽

Rural Areas ◽

Pathogenic Bacteria ◽

Removal Rate ◽

Treatment Plant ◽

Free Water ◽

Pilot Scale ◽

High Rate ◽

Total Coliforms ◽

Wastewater Treatment Systems

A comparative study on the removal of several pathogenic bacteria and their indicators was carried out at three natural wastewater treatment systems: stabilisation pond, high-rate algal pond and a free-water macrophyte system, retention times being 24, 5 and 3 days respectively. The macrophyte system showed higher removal efficiency for most of the groups, followed by stabilisation pond and high rate algal pond. All systems showed their highest efficiencies in the reduction of total coliforms, ranging from 98.68% for the stabilisation pond to 99.48% for the macrophyte process. Highly significant differences were found between the systems for bifidobacteria, C. perfringens and total coliforms removal. Pathogens and their indicators showed a different behaviour in their daily removal rate depending on the treatment plant.

Download Full-text

Nutrient removal in hybrid constructed wetlands: spatial-seasonal variation and the effect of vegetation

Water Science & Technology ◽

10.2166/wst.2019.196 ◽

2019 ◽

Vol 79 (10) ◽

pp. 1985-1994 ◽

Cited By ~ 2

Author(s):

Haq Nawaz Abbasi ◽

Jing Xie ◽

Syed Ikhlaq Hussain ◽

Xiwu Lu

Keyword(s):

Constructed Wetlands ◽

Water Depth ◽

Nutrient Removal ◽

Plant Root ◽

Pilot Scale ◽

Treatment Wetlands ◽

Opposite Trend ◽

Number Of Factors ◽

Plant Root System ◽

Floating Treatment Wetlands

Abstract Constructed wetlands (CWs) are an aesthetic and sustainable form to treat wastewater, however, their performance can be increased by improving a number of factors. The pilot-scale hybrid constructed wetland (CW) system was the combination of constructed floating treatment wetlands (CFWs) and horizontal subsurface flow constructed wetlands (HSFCWs); operated for a year and covered all seasons. The research was conducted to investigate the performance of the CW system regarding water depth, spatial, and seasonal removal of pollutants. Nine economical plants species were selected and divided into four groups to grow in CW-I to CW-IV, respectively. Removal increased along the bed and most of the total phosphorus (TP) removal occurred in the second bed, whereas total nitrogen (TN) and ammonium (NH4) removal were associated with the plant root system and biomass. Optimum removal of nutrients with respect to water depth was at 35 cm. TN and NH4 removal patterns were similar in different CWs. TN and NH4 removal were higher during summer compared to winter; only CW-IV showed the opposite trend.

Download Full-text