Urban Wastewater Treatment and Resource Utilization Based on Microalgae

A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Wastewater Treatment and Reuse".

Deadline for manuscript submissions: 30 June 2024 | Viewed by 3807

Special Issue Editor


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Guest Editor
Beijing Key Laboratory for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
Interests: wastewater treatment; wastewater reuse; microalgal water treatment; water bloom control; environmentally functional materials; environmental toxicity; ecotoxicity
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Special Issue Information

Dear Colleagues,

Wastewater treatment is an important part of water environmental protection. Microalgae are fast-growing, rich in high-value substances, can fix carbon dioxide through rapid photosynthesis, and can combine with bacteria or fungi to treat pollution, absorb and transform pollutants in water, promote the circulation of elements such as nitrogen and phosphorus, and control greenhouse gas emissions. Therefore, using microalgae to treat wastewater is considered a very promising solution for green and ecologically sustainable wastewater resource utilization. Currently, researchers in this field are conducting studies on how to use microalgae to achieve effective treatment of agricultural wastewater, industrial wastewater, municipal wastewater, and wastewaters containing harmful substances such as pesticides and antibiotics.

This Special Issue focuses on five separate elements: First, microalgae selection and process optimization for treatment of different types of urban wastewaters. While microalgae selection includes natural screening, breeding, genetic engineering breeding, mutagenesis breeding, etc., microalgae wastewater treatment process optimization includes pollutant treatment efficiency, process energy requirements and economic evaluation, etc. Second, technologies that can achieve microalgae immobilization, effective separation and harvesting of microalgae. Third, the development of microalgae water treatment equipment. Fourth, product development and technical environmental risk assessment based on microalgae water treatment. Finally, fifth, this Special Issue is looking to study microalgae–bacteria or microalgae–fungi combined water treatment technology and their mechanisms.

Lab-scale and pilot-scale research projects are welcome to submit manuscripts to this Special Issue. The content of this Special Issue is not limited to the above-mentioned areas, but any innovative full-length articles, reviews, and commentaries that can help improve the efficiency of urban wastewater treatment and resource utilization based on microalgae are very welcome. We are looking forward to receiving contributions to this Special Issue from researchers around the world.

Prof. Dr. Yu Hong
Guest Editor

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Keywords

  • microalgae-based urban wastewater treatment
  • microalgae selection and breeding
  • process optimization
  • microalgae–bacterial combined wastewater treatment
  • microalgae–fungus combined water treatment
  • microalgae immobilization
  • microalgae separation
  • microalgae harvesting
  • microalgae resource utilization
  • environmental risk assessment

Published Papers (3 papers)

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Research

12 pages, 1834 KiB  
Article
The Effect of Different Sludge Pretreatment Methods on Microalgae Performance and the Release of Pollutants in Hydrolysis Acidification Solutions
by Xiaoyan Wang, Yu Hong and Xiaoya Liu
Water 2023, 15(16), 2873; https://doi.org/10.3390/w15162873 - 09 Aug 2023
Viewed by 822
Abstract
Waste-activated sludge disposal has now become a serious global problem. After pretreatment, sludge was hydrolyzed and acidified to release nutrients. The effects of different sludge pretreatments on microalgal growth and contaminants in a hydrolysis acidification solution were compared. Alkalinization (NaOH), ultrasound (US), and [...] Read more.
Waste-activated sludge disposal has now become a serious global problem. After pretreatment, sludge was hydrolyzed and acidified to release nutrients. The effects of different sludge pretreatments on microalgal growth and contaminants in a hydrolysis acidification solution were compared. Alkalinization (NaOH), ultrasound (US), and combined pretreatment techniques (US-NaOH) all promoted contaminants’ release from the sludge by triggering microbial cell wall rupture and extracellular polymer dissolution. The organics released from the pretreated sludge were more readily and rapidly consumed due the presence of abundant microorganisms. The US group was more capable of releasing contaminants than the NaOH group, while the US-NaOH group overrode both. The growth characteristics, photosynthetic performance, and effluent treatment properties of Chlorella were observed in all group. In the untreated group, Chlorella exhibited higher algal density, maximum photochemical quantum yield, and effluent treatment capacity. The results demonstrated that sludge pretreatment could facilitate the release and rapid consumption of pollutants. Additionally, the NaOH pretreatment could remove the refractory organics to a higher degree, and could also accumulate more photosynthetic pigments. This study demonstrated the feasibility of Chlorella being used in practical scenarios such as hydrolytic acidification solutions for different sludge treatment methods, providing data for wastewater treatment and resource utilization. Full article
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13 pages, 998 KiB  
Article
Effect of Environmental Factors on Nitrite Nitrogen Absorption in Microalgae–Bacteria Consortia of Oocystis borgei and Rhodopseudomonas palustris
by Yukun Ma, Zhishen Luo, Jiazhan Zhong, Hanyi Zhang, Xianghu Huang, Changling Li and Yulei Zhang
Water 2023, 15(9), 1722; https://doi.org/10.3390/w15091722 - 28 Apr 2023
Cited by 3 | Viewed by 1441
Abstract
The effects of temperature, salinity, and illumination on the nitrite uptake rate of the microalgae–bacteria consortia of Oocystis borgei and Rhodopseudomonas palustris were investigated. The absorption rates of nitrite and the contribution rate of each component in the consortia under different temperatures (15, [...] Read more.
The effects of temperature, salinity, and illumination on the nitrite uptake rate of the microalgae–bacteria consortia of Oocystis borgei and Rhodopseudomonas palustris were investigated. The absorption rates of nitrite and the contribution rate of each component in the consortia under different temperatures (15, 20, 25, 30, 35 °C), illuminations (0, 15, 25, 35, 45 μmol·m−2·s−1), and salinities (0, 5, 15, 25, 35‰) were determined by stable isotope labeling technique. The single and combined effects of three environmental factors on nitrite uptake by the microalgae–bacteria consortia were analyzed using single-factor and orthogonal experiments. The single-factor experiment showed that the microalgae–bacteria consortia could absorb nitrite efficiently when the temperature, salinity, and illumination were 20~30 °C, 0~15‰, and 25~45 μmol·m−2·s−1, respectively, with the highest absorption rates were 2.086, 3.058, and 2.319 μg∙g−1∙h−1, respectively. The orthogonal experiment showed that the most efficient environmental conditions for nitrite uptake were 30 °C, 5‰ salinity, 35 μmol·m−2·s−1 illumination, and the rate of nitrite uptake by the microalgae–bacteria consortia was 3.204 μg∙g−1∙h−1. The results showed that the nitrite uptake rate of the O. borgeiR. palustris consortia was most affected by temperature, followed by salinity, and least by illumination. Under the same conditions, the nitrite absorption capacity of the microalgae–bacteria consortia was greater than that of single bacteria or algae, and R. palustris played a major role in the nitrite absorption of the consortia. The O. borgei and R. palustris consortia still maintain high nitrite absorption efficiency when the environment changes greatly, which has broad application prospects in the regulation and improvement of water quality in shrimp culture. Full article
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23 pages, 2942 KiB  
Article
CO2-Inorganic Carbon Auto-Buffering System for Efficient Ammonium Reclamation Coupled with Valuable Biomass Production in a Euryhaline Microalga Tetraselmis subcordiformis
by Yuhan Shen, Longren Liao, Weidong Wu, Haoyu Zhang, Xiuyuan Ran, Tonghui Xie, Yongkui Zhang and Changhong Yao
Water 2023, 15(9), 1671; https://doi.org/10.3390/w15091671 - 25 Apr 2023
Cited by 1 | Viewed by 1111
Abstract
The performance of microalgae-based wastewater treatment processes for ammonium-N (NH4+-N) removal depends on the maintenance of a favorable pH that is critical for minimizing nitrogen escape in the form of free ammonia (NH3) and preventing high-NH3 or [...] Read more.
The performance of microalgae-based wastewater treatment processes for ammonium-N (NH4+-N) removal depends on the maintenance of a favorable pH that is critical for minimizing nitrogen escape in the form of free ammonia (NH3) and preventing high-NH3 or extreme-pH stress. This study developed a CO2-inorganic carbon (CO2-IC) buffering system that automatically stabilized pH with the supply of a carbon source for efficient photosynthetic reclamation of NH4+-N by a euryhaline microalga Tetraselmis subcordiformis. The soluble (NaHCO3) and insoluble (CaCO3 and MgCO3) ICs were compared for this purpose. The pH was well controlled in the range of 6.5~8.5 in the CO2-IC system, which was suitable for the photosynthetic growth of T. subcordiformis. The NH4+-N (100 mg/L) was almost completely removed in three days, with the maximum removal rate of 60.13 mg N/L/day and minimal N escape of 19.65% obtained in the CO2-NaHCO3 system. The CO2-IC system also restricted the release of extracellular organic matter by preventing stress conditions. The CO2-NaHCO3 system enabled the highest “normal” starch production suitable for fermentation, while the CO2-CaCO3/MgCO3 system facilitated high-amylose starch accumulation that was conducive to producing bio-based materials and health-promoting ingredients. The proteins accumulated in T. subcordiformis were of good quality for animal feeds. Full article
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