Research

2867 KiB

Open AccessArticle

Treatment of Rural Wastewater Using a Spiral Fiber Based Salinity-Persistent Sequencing Batch Biofilm Reactor

by Ying-Xin Zhao, Chun-Fang Chao, Si-Yuan Zhai, Zi-Jian Wang and Min Ji

Water 2017, 9(12), 970; https://doi.org/10.3390/w9120970 - 12 Dec 2017

Cited by 11 | Viewed by 4450

Differing from municipal wastewater, rural wastewater in salinization areas is characterized with arbitrary discharge and high concentration of salt, COD, nitrogen and phosphorus, which would cause severe deterioration of rivers and lakes. To overcome the limits of traditional biological processes, a spiral fiber [...] Read more.

Differing from municipal wastewater, rural wastewater in salinization areas is characterized with arbitrary discharge and high concentration of salt, COD, nitrogen and phosphorus, which would cause severe deterioration of rivers and lakes. To overcome the limits of traditional biological processes, a spiral fiber based salinity-persistent Sequencing Biofilm Batch Reactor (SBBR) was developed and investigated with synthetic rural wastewater (COD = 500 mg/L, NH₄⁺-N = 50 mg/L, TP = 6 mg/L) under different salinity (0.0–10.0 g/L of NaCl). Results indicated that a quick start-up could be achieved in 15 days, along with sufficient biomass up to 7275 mg/L. During operating period, the removal of COD, NH₄⁺-N, TN was almost not disturbed by salt varying from 0.0 to 10.0 g/L with stable efficiency reaching 92%, 82% and 80%, respectively. Although TP could be removed at high efficiency of 90% in low salinity conditions (from 0.0 to 5.0 g/L of NaCl), it was seriously inhibited due to nitrite accumulation and reduction of Phosphorus Accumulating Organisms (PAOs) after addition of 10.0 g/L of salt. The behavior proposed in this study will provide theoretical foundation and guidance for application of SBBR in saline rural wastewater treatment. Full article

(This article belongs to the Special Issue Biological Treatment of Wastewater)

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1896 KiB

Open AccessArticle

Characteristics of Bacterial Communities in Cyanobacteria-Blooming Aquaculture Wastewater Influenced by the Phytoremediation with Water Hyacinth

by Qing Zhou, Ting Chen and Shiqun Han

Water 2017, 9(12), 956; https://doi.org/10.3390/w9120956 - 07 Dec 2017

Cited by 8 | Viewed by 6742

Abstract

Cyanobacterial blooms often occur in aquaculture wastewater in China. A floating plant, water hyacinth has been widely used to treat this wastewater. Little is known, however, about bacterial community characteristics and the risk of potential pathogens in cyanobacteria-blooming aquaculture wastewater remediated by water [...] Read more.

Cyanobacterial blooms often occur in aquaculture wastewater in China. A floating plant, water hyacinth has been widely used to treat this wastewater. Little is known, however, about bacterial community characteristics and the risk of potential pathogens in cyanobacteria-blooming aquaculture wastewater remediated by water hyacinth. In wastewater treated with water hyacinth, we used culture enumeration and high-throughput sequencing to explore the characteristics of bacterial communities, the status of coliform bacteria, and pathogenic bacteria potentially conducive to human disease. Our results indicated that the relative abundance of Acidobacteria, Planctomycetes, Actinobacteria, Chlorobi, Cyanobacteria, Proteobacteria, and phylum OD1 in cyanobacteria-blooming aquaculture wastewater were significantly influenced by water hyacinth. After 30 days, the relative abundance of Proteobacteria and phylum OD1 in the water hyacinth treatments increased remarkably, while the relative abundance of the other 5 phyla in treatment was significantly reduced compared with the controls. In 21 major families, the relative abundance of Comamonadaceae, Oxalobacteraceae, Rhodocylclaceae, and an unnamed group from phylum OD1 increased significantly in the water hyacinth treatments compared with the controls. The number of total coliforms in wastewater treated by water hyacinth was significantly elevated and higher than controls during the first 6–18 days, with the maximum reaching 23,800 MPN/L. The level of potential pathogenic bacteria in wastewater treated by water hyacinth significantly reduced compared with the controls after 18 days, but it significantly increased from the initial level. It appears that water hyacinth by itself is not an effective treatment for reducing potential pathogens in aquaculture water. Full article

(This article belongs to the Special Issue Biological Treatment of Wastewater)

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4666 KiB

Open AccessArticle

Comparison of the Results from Microscopic Tests Concerning the Quality of Activated Sludge and Effluent

by Aleksandra Sowinska, Maciej Pawlak, Jakub Mazurkiewicz and Marta Pacholska

Water 2017, 9(12), 918; https://doi.org/10.3390/w9120918 - 26 Nov 2017

Cited by 13 | Viewed by 6028

Abstract

Physicochemical studies on wastewater quality and microscopic analyses of activated sludge are necessary to properly evaluate the condition of activated sludge. The aim of this study was to evaluate the application of the sludge biotic index to determine when a change in treatment [...] Read more.

Physicochemical studies on wastewater quality and microscopic analyses of activated sludge are necessary to properly evaluate the condition of activated sludge. The aim of this study was to evaluate the application of the sludge biotic index to determine when a change in treatment quality is short-lived, caused by, e.g., a change in influent quality or quantity, and when it indicates adverse changes in the biocenosis of activated sludge, which would very likely result in the lower efficiency of wastewater treatment in the near future. The objects of the study were two identical parallel running small wastewater treatment plants. The following indicators of contamination were analyzed: the chemical oxygen demand (COD), biochemical oxygen demand (BOD₅), and total suspended solids (TSS). The authors additionally carried out a microscopic analysis. The study confirmed a correlation between the sludge biotic index and the removal efficiency of COD and BOD₅; however, no correlation was found between the sludge biotic index and the removal efficiency of total suspended solids. The presence of metazoan microorganisms coincided in time with a good effluent treatment efficiency. When their quantity declined, a decrease in the efficiency of wastewater treatment was also observed. Full article

(This article belongs to the Special Issue Biological Treatment of Wastewater)

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2667 KiB

Open AccessArticle

Cyanobacterial Nitrogen Fixation Influences the Nitrogen Removal Efficiency in a Constructed Wetland

by Xiaodong Zhang, Xin Jia, Liang Yan, Jinzhi Wang, Xiaoming Kang and Lijuan Cui

Water 2017, 9(11), 865; https://doi.org/10.3390/w9110865 - 07 Nov 2017

Cited by 3 | Viewed by 3621

Abstract

Nitrogen removal efficiency in constructed wetlands (CW) is influenced by multiple environmental factors. However, little is known about the role of cyanobacterial nitrogen fixation in affecting nitrogen removal efficiency. This study investigated how cyanobacterial nitrogen fixation affects the efficiency, at which a CW [...] Read more.

Nitrogen removal efficiency in constructed wetlands (CW) is influenced by multiple environmental factors. However, little is known about the role of cyanobacterial nitrogen fixation in affecting nitrogen removal efficiency. This study investigated how cyanobacterial nitrogen fixation affects the efficiency, at which a CW removes nitrogen from an associated artificial lake (AL) in Beijing. For this purpose, we measured cell densities of N-fixing and non-N-fixing cyanobacteria, the aquatic nitrogen fixation rate (R_Nfix), and the concentration of various nitrogen fractions over the growing season (April–November) of 2014 in both AL and CW. We found that the removal of particulate organic nitrogen (PON) contributed to >90% of the total nitrogen removal in the CW. The removal efficiency of PON was lower during August–October (55.45 ± 27.49%) than during April–July (68.86 ± 8.83%). Phytoplankton proliferation in summer, as one of the main sources of PON, may have exceeded the capacity of the CW and led to declines in PON removal efficiency. R_Nfix peaked in July–October (3–169 ng N·L⁻¹·h⁻¹) and was positively correlated with both PON concentration and the cell density of N-fixing Anabaena sp. over the growing season, suggesting that aquatic nitrogen fixation (primarily in the AL) may increase PON and thereby reduce the its removal efficiency in the CW. Full article

(This article belongs to the Special Issue Biological Treatment of Wastewater)

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1292 KiB

Open AccessArticle

Performance of Denitrifying Phosphate Removal via Nitrite from Slaughterhouse Wastewater Treatment at Low Temperature

by Min Pan, Xiaoming Huang, Guangxue Wu, Yuansheng Hu, Yan Yang and Xinmin Zhan

Water 2017, 9(11), 818; https://doi.org/10.3390/w9110818 - 31 Oct 2017

Cited by 11 | Viewed by 5132

Abstract

This study aims to investigate the effects of the organic loading rate (OLR) and the aeration rate on denitrifying phosphate removal (DPR) from slaughterhouse wastewater treated at a temperature of 11 °C. Three laboratory-scale intermittently aerated sequencing batch reactors (IASBRs) were set up [...] Read more.

This study aims to investigate the effects of the organic loading rate (OLR) and the aeration rate on denitrifying phosphate removal (DPR) from slaughterhouse wastewater treated at a temperature of 11 °C. Three laboratory-scale intermittently aerated sequencing batch reactors (IASBRs) were set up and three OLRs and five aeration rates were employed in the study. The results indicated that efficient removals of nitrogen (N) and phosphorus (P) from DPR were achieved. Furthermore, the intermittent aeration pattern benefitted both the phosphorus-accumulating organisms (PAOs) and the denitrifying phosphorus-accumulating organisms (DPAOs) that accumulated at 11 °C. The ratio of P uptake in the aeration periods/P release in the non-aeration periods was in the range of 0.94–1.10 in the three stages. The relationship between the specific poly-β-hydroxybutyrate (PHB) degradation rate (z), the specific P removal rate (x), and the specific total oxidized nitrogen(TON) reduction rate (y) can be fitted approximately as a plane (

z = 1.3626 x + 0.2882 y - 0.6722

, R² = 0.83). Full article

(This article belongs to the Special Issue Biological Treatment of Wastewater)

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2312 KiB

Open AccessArticle

Heterotrophic Nitrification-Aerobic Denitrification Performance of Strain Y-12 under Low Temperature and High Concentration of Inorganic Nitrogen Conditions

by Qing Ye, Kaili Li, Zhenlun Li, Yi Xu, Tengxia He, Wenhao Tang and Shudi Xiang

Water 2017, 9(11), 835; https://doi.org/10.3390/w9110835 - 30 Oct 2017

Cited by 33 | Viewed by 4870

Abstract

An aerobic nitrite-denitrifying bacterium Pseudomonas putida Y-12 was used to remove sole and mixed nitrogen sources at 15 °C. When strain Y-12 was incubated for 4 days with a sole nitrogen source and initial NH₄⁺-N, NO₃⁻-N, and [...] Read more.

An aerobic nitrite-denitrifying bacterium Pseudomonas putida Y-12 was used to remove sole and mixed nitrogen sources at 15 °C. When strain Y-12 was incubated for 4 days with a sole nitrogen source and initial NH₄⁺-N, NO₃⁻-N, and NO₂⁻-N concentrations of 208.1, 204.7, and 199.0 mg/L, respectively, the removal ratios of NH₄⁺-N, NO₃⁻-N, and NO₂⁻-N were 98.8, 73.6, and 77.1%, respectively. The average removal rates of NH₄⁺-N, NO₃⁻-N, and NO₂⁻-N reached 2.14, 1.57, and 1.60 mg/L/h, respectively. Intermediate products (NO₃⁻-N and NO₂⁻-N) were detected at a low level. Total nitrogen removal was mainly achieved during the stationary phase in the denitrification process. All the results indicated that strain Y-12 could perform heterotrophic nitrification and aerobic denitrification at 15 °C, which was beneficial for future applications in wastewater treatment at low temperatures. Full article

(This article belongs to the Special Issue Biological Treatment of Wastewater)

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1555 KiB

Open AccessArticle

Characterization of a Microbial Community in an Anammox Process Using Stored Anammox Sludge

by Wenjing Chen, Xiaohu Dai, Dawen Cao, Xiaona Hu, Wenru Liu and Dianhai Yang

Water 2017, 9(11), 829; https://doi.org/10.3390/w9110829 - 29 Oct 2017

Cited by 17 | Viewed by 5390

Abstract

This study investigated a rapid start-up anaerobic ammonium oxidation (Anammox) process by inoculation with stored Anammox sludge and characterized the associated microbial communities. The Anammox process took only 43 days to start. A high nitrogen removal rate of 1.13 kg N m⁻³ [...] Read more.

This study investigated a rapid start-up anaerobic ammonium oxidation (Anammox) process by inoculation with stored Anammox sludge and characterized the associated microbial communities. The Anammox process took only 43 days to start. A high nitrogen removal rate of 1.13 kg N m⁻³ d⁻¹ and a nitrogen loading rate of 1.28 kg N m⁻³ d⁻¹ were achieved. The ratio of ammonium removal to nitrite removal to nitrate production (1:1:0.2) was slightly lower than the theoretical value, which indicated nitrogen removal by denitrification in the reactor. Illumina high-throughput sequencing of sludge samples confirmed the co-existence of Anammox bacteria and denitrifying bacteria in the reactor and demonstrated that denitrifying bacteria play a role in nitrogen removal during the Anammox process. The dominant microbes in the reactor were Proteobacteria, Chlorobi, Chloroflexi, and Planctomycetes. However, only one species of Anammox bacteria, Candidatus jettenia, was identified and had an abundance of 4.92%. Our results illustrate the relationship between Anammox reactor performance and microbial community succession. Full article

(This article belongs to the Special Issue Biological Treatment of Wastewater)

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1298 KiB

Open AccessArticle

Study on Effects of Electron Donors on Phosphine Production from Anaerobic Activated Sludge

by Jianping Cao, Chaosheng Zhang, Hongwei Rong, Meihua Zhao, Wei Wei and Limin Zhao

Water 2017, 9(8), 563; https://doi.org/10.3390/w9080563 - 30 Jul 2017

Cited by 7 | Viewed by 5211

Abstract

The effects of different types and concentrations of electron donors (glucose, starch, methanol and sodium acetate) on the formation of phosphine from anaerobic activated sludge that has been domesticated for a prolonged period were studied in small batch experiments. The results show that [...] Read more.

The effects of different types and concentrations of electron donors (glucose, starch, methanol and sodium acetate) on the formation of phosphine from anaerobic activated sludge that has been domesticated for a prolonged period were studied in small batch experiments. The results show that types and concentrations of electron donor have significant effects on the production of phosphine from anaerobic activated sludge. Among them, glucose was the most favourable electron donor, whereas sodium acetate was the least favourable electron donor for the removal of phosphorus and the production of phosphine. Higher concentrations of electron donors were more favourable for the reduction of phosphate into phosphine, and supplying more than nine times the amount of electron donor as theoretically required for the reduction of phosphate into phosphine was favourable for the production of phosphine. Full article

(This article belongs to the Special Issue Biological Treatment of Wastewater)

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1893 KiB

Open AccessArticle

Characteristics and Biodegradability of Wastewater Organic Matter in Municipal Wastewater Treatment Plants Collecting Domestic Wastewater and Industrial Discharge

by Yun-Young Choi, Seung-Ryong Baek, Jae-In Kim, Jeong-Woo Choi, Jin Hur, Tae-U Lee, Cheol-Joon Park and Byung Joon Lee

Water 2017, 9(6), 409; https://doi.org/10.3390/w9060409 - 08 Jun 2017

Cited by 97 | Viewed by 15187

Abstract

Municipal wastewater treatment plants (WWTPs) in Korea collect and treat not only domestic wastewater, but also discharge from industrial complexes. However, some industrial discharges contain a large amount of non-biodegradable organic matter, which cannot be treated properly in a conventional biological WWTP. This [...] Read more.

Municipal wastewater treatment plants (WWTPs) in Korea collect and treat not only domestic wastewater, but also discharge from industrial complexes. However, some industrial discharges contain a large amount of non-biodegradable organic matter, which cannot be treated properly in a conventional biological WWTP. This study aimed to investigate the characteristics and biodegradability of the wastewater organic matter contained in the industrial discharges and to examine the fate of the industrial discharges in a biological WWTP. In contrast to most previous studies targeting a specific group of organic compounds or traditional water quality indices, such as biological oxygen demand (BOD) and chemical oxygen demand (COD), this study was purposed to quantify and characterize the biodegradable and nonbiodegradable fractions of the wastewater organic matter. Chemical oxygen demand (COD) fractionation tests and fluorescence spectroscopy revealed that the industrial discharge from dyeing or pulp mill factories contained more non-biodegradable soluble organic matter than did the domestic wastewater. Statistical analysis on the WWTPs’ monitoring data indicated that the industrial discharge containing non-biodegradable soluble organic matter was not treated effectively in a biological WWTP, but was escaping from the system. Thus, industrial discharge that contained non-biodegradable soluble organic matter was a major factor in the decrease in biodegradability of the discharge, affecting the ultimate fate of wastewater organic matter in a biological WWTP. Further application of COD fractionation and fluorescence spectroscopy to wastewaters, with various industrial discharges, will help scientists and engineers to better design and operate a biological WWTP, by understanding the fate of wastewater organic matter. Full article

(This article belongs to the Special Issue Biological Treatment of Wastewater)

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