scholarly journals Graphene-Modulated Removal Performance of Nitrogen and Phosphorus Pollutants in a Sequencing Batch Chlorella Reactor

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2181 ◽  
Author(s):  
Gonghan Xia ◽  
Wenlai Xu ◽  
Qinglin Fang ◽  
Zishen Mou ◽  
Zhicheng Pan
Keyword(s):  
Optical Microscopy ◽  
Sewage Treatment ◽  
Ammonia Nitrogen ◽  
Pollutant Removal ◽  
Plate Count ◽  
Nitrogen And Phosphorus ◽  
Removal Rates ◽  
Practical Support ◽  
Plate Count Method ◽  
The Impact

In this work, the influence of graphene on nitrogen and phosphorus in a batch Chlorella reactor was studied. The impact of graphene on the removal performance of Chlorella was investigated in a home-built sewage treatment system with seven identical sequencing batch Chlorella reactors with graphene contents of 0 mg/L (T1), 0.05 mg/L (T2), 0.1 mg/L (T3), 0.2 mg/L (T4), 0.4 mg/L (T5), 0.8 mg/L (T6) and 10 mg/L (T7). The influence of graphene concentration and reaction time on the pollutant removal performance was studied. The malondialdehyde (MDA) and total superoxide dismutase (SOD) concentrations in each reactor were measured, and optical microscopy and scanning electron microscopy (SEM) characterizations were performed to determine the related mechanism. The results show that after 168 h, the total nitrogen (TN), ammonia nitrogen (AN) and total phosphorus (TP) removal rates of reactors T1–T7 become stable, and the TN, AN and TP removal rates were gradually reduced with increasing graphene concentration. At 96 h, the concentrations of both MDA and SOD in T1–T7 gradually increased as the graphene concentration increased. In optical microscopy and SEM measurements, it was found that graphene was adsorbed on the surface of Chlorella, and entered Chlorella cells, deforming and reducing Chlorella. Through the blood plate count method, we estimated an average Chlorella reduction of 16%. According to the water quality and microscopic experiments, it can be concluded that the addition of graphene causes oxidative damage to microalgae and destruction of the Chlorella cell wall and cell membrane, inhibiting the nitrogen and phosphorus removal in Chlorella reactors. This study provides theoretical and practical support for the safe use of graphene.

scholarly journals Improving the Treatment Performance of Low Impact Development Practices—Comparison of Sand and Bioretention Soil Mixtures Using Column Experiments

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1210
Author(s):  
Abtin Shahrokh Hamedani ◽  
Arianne Bazilio ◽  
Hanieh Soleimanifar ◽  
Heather Shipley ◽  
Marcio Giacomoni
Keyword(s):  
Phosphorus Removal ◽  
Low Impact Development ◽  
Pollutant Removal ◽  
Control Measures ◽  
Column Experiments ◽  
Removal Rates ◽  
Treatment Performance ◽  
Soil Mixtures ◽  
Limestone Sand ◽  
The Impact

Low impact development (LID) practices, such as bioretention and sand filter basins, are stormwater control measures designed to mitigate the adverse impacts of urbanization on stormwater. LID treatment performance is highly dependent on the media characteristics. The literature suggests that bioretention media often leach nutrients in the stormwater effluent. The objective of this study was to analyze the treatment performance of different sand and bioretention soil mixtures. Specifically, this investigation aimed to answer whether the use of limestone and recycled glass could improve the treatment performance of bioretention systems. Column experiments were designed to assess (1) the removal efficiencies of different sand and bioretention soil mixtures and (2) the impact of plant uptake on removal rates. Enhanced pollutant removal was observed for the custom blends with addition of limestone sand, indicating mean dissolved and total phosphorus removal of 44.5% and 32.6% respectively, while the conventional bioretention soil mixtures leached phosphorus. Moreover, improved treatment of dissolved and total copper was achieved with mean removal rates of 70.7% and 93.4%, respectively. The results suggest that the nutrient effluent concentration decreased with the addition of plants, with mean phosphorus removal of 72.4%, and mean nitrogen removal of 22% for the limestone blend.

The ecological filter system for treatment of decentralized wastewater

2016 ◽  
Vol 74 (7) ◽  
pp. 1553-1560
Author(s):  
Kun Zhong ◽  
Yi-yong Luo ◽  
Zheng-song Wu ◽  
Qiang He ◽  
Xue-bin Hu ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Organic Pollutants ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Nitrogen And Phosphorus ◽  
Treatment Technology ◽  
Removal Rates ◽  
Carbon Nitrogen Ratio ◽  
Ecological Filter ◽  
Aerated Filter

A vertical flow constructed wetland was combined with a biological aerated filter to develop an ecological filter, and to obtain the optimal operating parameters: The hydraulic loading was 1.55 m3/(m2·d), carbon–nitrogen ratio was 10, and gas–water ratio was 6. The experimental results demonstrated considerable removal efficiency of chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), total nitrogen (TN), and total phosphorus (TP) in wastewater by the ecological filter, with average removal rates of 83.79%, 93.10%, 52.90%, and 79.07%, respectively. Concentration of NH4+-N after treatment met the level-A discharge standard of GB18918-2002. Compared with non-plant filter, the ecological filter improved average removal efficiency of COD, NH4+-N, TN, and TP by 13.03%, 25.30%, 14.80%, and 2.32%, respectively: thus, plants significantly contribute to the removal of organic pollutants and nitrogen. Through microporous aeration and O2 secretion of plants, the ecological filter formed an aerobic–anaerobic–aerobic alternating environment; thus aerobic and anaerobic microbes were active and effectively removed organic pollutants. Meanwhile, nitrogen and phosphorus were directly assimilated by plants and as nutrients of microorganisms. Meanwhile, pollutants were removed through nitrification, denitrification, filtration, adsorption, and interception by the filler. High removal rates of pollutants on the ecological filter proved that it is an effective wastewater-treatment technology for decentralized wastewater of mountainous towns.

Effect of Phenol on Treatment of Sewage from Channel Discharge with Biological Accelerator-Biofilm Process

2011 ◽  
Vol 243-249 ◽  
pp. 3761-3764
Author(s):  
Gai Mei Guo
Keyword(s):  
Treatment Process ◽  
Sewage Treatment ◽  
Ammonia Nitrogen ◽  
Removal Rates ◽  
Promotion Effect ◽  
Initial Concentration ◽  
Research Results ◽  
Negative Effect ◽  
Biofilm Process

The research studied enhanced treatment of sewage from discharging points of rivers by biofilm process dosing with enzyme and the effect of phenol on removal rates of the main pollution indexes, and investigated promotion effect of enzyme (including the laboratory developed compounded enzyme and the foreign composite enzyme) on treatment of sewage by biofilm process. The research results indicated that when initial concentration of phenol was 5mg/L, the removal rates of phenol, CODCrand ammonia nitrogen obviously decreased compared to no phenol added to reactor A, B and C, and the negative effect of phenol was smaller on reactor B and C than on reactor A. Moreover, enzyme had good promotion effect on biofilm process during the sewage treatment process.

scholarly journals Bacterial community shift and effects of the inclusion of a mixed psychrotrophic bacteria strain for sewage treatment in constructed wetland in winter seasons

2021 ◽  
Author(s):  
xiaoyan xu ◽  
Jie Jiang ◽  
Zhinan Guo ◽  
Lianglun Sun ◽  
Meizhen Tang
Keyword(s):  
Low Temperature ◽  
Constructed Wetlands ◽  
High Throughput Sequencing ◽  
Sewage Treatment ◽  
High Capacity ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Nitrogen And Phosphorus ◽  
Degradation Kinetic ◽  
Psychrotrophic Bacteria

Abstract The mechanism of wastewater treatment based on psychrophilic strains to improve the denitrification efficiency of constructed wetlands at low temperatures has already become a new hotspot. In this study, three mixed psychrophilic strains (Psychrobacter TM-1, Sphingobacterium TM-2 and Pseudomonas TM-3) with high capacity of denitrification were added into a vertical-flow constructed wetlands (CWs), and the effect of the mixed strains on CWs sewage treatment was evaluated. The removal efficiency of chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), total nitrogen (TN) and total phosphorus (TP) was quantified to establish the degradation kinetic model and determine the best dosage of the mixed strains. The effect mechanism of the mixed strains on indigenous microbial community and the change of sewage treatment performance in low temperature constructed wetlands was clarified by high-throughput sequencing technology. The results showed that the mixed strains can effectively remove the organic pollutants (nitrogen and phosphorus) and the optimum dosage of the mixed strain was 2.5%,with average removal rates of 1.52, 2.12, 2.07 and 1.29 times than those of the control. Meanwhile, the dominant strains in the CWs were Proteobacteria (31.23–44.34%), Chloroflexi (12.04–19.05%), Actinobacteria (10.6-20.62%), Acidobacteria (8.23–11.65%), Firmicutes (2.23–15.95%) and Bacteroidetes (4.01–18.9%). These findings provide a basis for the removal of pollutants in constructed wetlands at low temperature.

scholarly journals Performance of Anaerobic Baffled Reactor for Decentralized Wastewater Treatment in Urban Malang, Indonesia

Processes ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 184 ◽  
Author(s):  
Anie Yulistyorini ◽  
Miller Camargo-Valero ◽  
Sukarni Sukarni ◽  
Nugroho Suryoputro ◽  
Mujiyono Mujiyono ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Urban Areas ◽  
Sewage Treatment ◽  
Research Work ◽  
Domestic Wastewater ◽  
Poor Quality ◽  
Pollutant Removal ◽  
Treated Effluent ◽  
The Republic ◽  
The Impact

In order to assess the impact of the Sanitation by Communities (SANIMAS) program for community-led sanitation in Indonesia (established in 2002), this research work was conducted with the aim of characterizing the current performance of anaerobic baffled reactors (ABRs), which were deployed in high numbers for the provision of domestic wastewater treatment in densely populated urban areas in Malang (Indonesia). Small and decentralized sewage treatment facilities serve ≈3% of the total population in Malang, including 89 ABR treatment plants. Our findings reveal that only 14% of the 89 ABRs in Malang have an acceptable performance with regard to pollutant removal and integrity of their building structure, but the majority of them produce a treated effluent of poor quality, according to discharge consents set by the Ministry of Environment and Forestry of the Republic of Indonesia (Regulation No. P.68/2016). Clearly the lack of consistent operation and maintenance practices have had a detrimental effect on these decentralized sewage treatment systems, despite their robustness and buffer capacity to cope with changes in organic and hydraulic loading rates. Urbanization will continue to exert pressure on the provision of sanitation services in lower and middle economies, and the role of decentralized sewage management systems is expected to be prominent in the UN’s Sustainable Development Goals era (2015–2030); however, sustainable service delivery must be conceived beyond the provision of sanitation infrastructure.

The impact of sea water flushing on biological nitrification-denitrification activated sludge sewage treatment process

2002 ◽  
Vol 46 (11-12) ◽  
pp. 209-216 ◽  
Author(s):  
S.M. Yu ◽  
W.Y. Leung ◽  
K.M. Ho ◽  
P.F. Greenfield ◽  
W.W. Eckenfelder
Keyword(s):  
Activated Sludge ◽  
Capital Investment ◽  
Sea Water ◽  
Initial Period ◽  
Sewage Treatment ◽  
Ammonia Nitrogen ◽  
Inhibitory Effects ◽  
Original Design ◽  
Activated Sludge Processes ◽  
The Impact

The process performance of the two largest activated sludge processes in Hong Kong, the Sha Tin and the Tai Po Sewage Treatment Works (STW), deteriorated in the initial period after the introduction of seawater flushing in 1995 and 1996, respectively. High effluent ammonia nitrogen (NH4-N) and total suspended solids (TSS) in excess of the discharge standards resulted from incomplete nitrification and changes in floc characteristics. A desktop study on the inhibitory effects of salinity, particularly on nitrification, was subsequently conducted using the Tai Po STW operating data. To assist the upgrade of the Sha Tin STW a five-month extensive bench-scale investigation on a simple but flexible modified Ludzack-Ettinger configuration with bio-selector was conducted to quantify the inhibitory effects due to the saline concentration. The Sha Tin STW upgrade consists of restoration of its original design capacity (conventional process) of 205,000 m3/day from its currently much reduced capacity as a Bardenpho process. Only the volume of the existing biological process and clarifier is to be utilized. The saline concentration ranges from 3,500 up to 6,500 mg Cl-/L, both daily and seasonally. High and greatly fluctuating saline concentrations have been known to inhibit nitrification. Design consideration should also be given to the peak daily and seasonal TKN loading of up to three times the average. Although the nitrifiers maximum specific growth rate was significantly reduced to a low 0.25 day−1, the inhibition was considered to be tolerable with effluent NH4-N and NO3-N consistently at < 1 and < 6 mg/L. The bio-selector was demonstrated to be efficient in control of sludge foaming and bulking with SVI consistently ≤ 125 mL/g. Results from the IAWQ Model No. 1 and the hydraulic model of the secondary clarifiers allowed overall process capacity maximization. With an anoxic mass fraction of 25-30%, operating sludge age of 9-14 days and SVI ≤ 125 mL/g, both the design requirements and the effluent discharge standards could be met. Without these investigations, an unnecessarily large reaction basin and secondary clarifier volume, and hence capital investment, would have resulted.

The Study of Hospital Wastewater Treatment by Combined Pure-Oxygen Aeration and A/O Process

2012 ◽  
Vol 178-181 ◽  
pp. 627-632
Author(s):  
Wei Wei Yu ◽  
Zhi Zhang ◽  
Shi Ling Chen ◽  
Tao Wang ◽  
Teng Can Zhang
Keyword(s):  
Wastewater Treatment ◽  
Sewage Treatment ◽  
Ammonia Nitrogen ◽  
Pollutant Removal ◽  
Nitrogen Efficiency ◽  
Pure Oxygen ◽  
Removal Mechanism ◽  
Hospital Wastewater ◽  
Actual Application ◽  
Industrial Sewage

The field in which pure oxygen aeration is applied to sewage treatment is extensive. In actual application it is more suitable for the degradation of industrial sewage. Pure oxygen aeration has unique merit compared with common air aeration. This article introduced the effect by pure oxygen aeration. The study shows pure oxygen aeration is an effective pollutant removal mechanism, and at the same time proposes the best dissolved oxygen is at 3 mg/l. The average removal rates of CODcr, NH3-N, TN are 73%, 50%, 55% respectively. The conclusion is that pure oxygen aeration for hospital wastewater the CODcr removing rate is higher than ammonia nitrogen and total nitrogen efficiency.

scholarly journals Impact of Changes of Land Use on Water Quality, from Tropical Forest to Anthropogenic Occupation: A Multivariate Approach

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1518 ◽  
Author(s):  
Alexis Rodríguez-Romero ◽  
Axel Rico-Sánchez ◽  
Erick Mendoza-Martínez ◽  
Andrea Gómez-Ruiz ◽  
Jacinto Sedeño-Díaz ◽  
...  
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Seasonal Variations ◽  
Cloud Forest ◽  
Ammonia Nitrogen ◽  
Fecal Coliforms ◽  
Vegetation Coverage ◽  
Nitrogen And Phosphorus ◽  
The Impact ◽  
The Relationship

Worldwide, it is acknowledged that changes of land use influence water quality; however, in tropical forests, the relationship between land use and water quality is still poorly understood. This study assessed spatial and seasonal variations in water quality, and the relationship between water quality and changes of land use in the Bobos-Nautla River, whose upper course runs across a patch of a tropical cloud forest. Spatial and seasonal variations in water quality and land use were assessed with multivariate tools. A cluster analysis, as well as a Principal Component Analysis (PCA-3D), identified three groups of sites: (1) an upper portion, which showed the best water quality and the broadest natural vegetation coverage; (2) a middle course, with high nitrogen and phosphorus concentrations associated with extensive agricultural uses; and (3) a lower course, characterized by the highest levels of total and fecal coliforms, as well as ammonia nitrogen, associated with the highest percentage of urbanization and human settlements. Our findings demonstrate the impact of changes of land use on water quality of rivers running through cloud forests in tropical zones, which are currently endangered ecosystems.

Treatment Effect of Multilayer Vermifiltration on Living Wastewater

2011 ◽  
Vol 343-344 ◽  
pp. 789-794
Author(s):  
Yin Sheng Li ◽  
Xiu Hong Wang ◽  
Yi Qi Dai ◽  
Jiang Ping Qiu ◽  
Paul Robin ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Treatment Effect ◽  
Sewage Treatment ◽  
Pollutant Removal ◽  
Removal Rates ◽  
Preliminary Results ◽  
Rural Living ◽  
The Future ◽  
Organic Wastewater

Former studies and application of vermifiltration process to organic wastewater treatment has given an affirmative effect for the pollutant removal in wastewater. It could be used for the disperse wastewater treatment, especially for rural living sewage. We developed a new multilayer vermifiltration system in this study, expecting to enhance this ability for the disposal of rural living sewage. The result showed that all the COD, BOD5 and SS values in outflow after vermifiltration could meet GB18918-2002. The removal rates of COD，BOD5 and SS were above 75%, 85% and 90% respectively. The N and P could be partly removed. These preliminary results give a positive prospective for the application of multilayer vermifiltration in rural sewage treatment in the future.

Impact of SRT on Simultaneous Nitrification and Denitrification in a Carrousel Oxidation Ditch for Sewage Treatment

2012 ◽  
Vol 550-553 ◽  
pp. 2104-2107
Author(s):  
Yi Ming Chen
Keyword(s):  
Sewage Treatment ◽  
Pilot Scale ◽  
Ammonia Nitrogen ◽  
Municipal Sewage ◽  
Simultaneous Nitrification And Denitrification ◽  
Oxidation Ditch ◽  
Treatment Efficiency ◽  
Nitrification And Denitrification ◽  
Carrousel Oxidation Ditch ◽  
The Impact

The impact of SRT on simultaneous nitrification and denitrification (SND) in the Carrousel Oxidation Ditch was carried out based on pilot-scale to treat low COD/TN municipal sewage. The impact factor, sludge retention time (SRT), was investigated on the occurrence of SND. The experiment results showed that in the oxygen-deficient environment whose DO was 0.3 mg/L, R of 50%, MLSS of 4000 mg/L, the treatment efficiency achieved the best with SRT of 20 d, the COD, ammonia nitrogen, total nitrogen (TN) of effluent were lower than 32 mg/L, 5 mg/L, 13 mg/L, respectively, which was observed efficient phenomenon of SND. Overall, these results demonstrated that the Carrousel Oxidation Ditch with the occurrence of SND could have the potential to treat low C/N sewage.

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