scholarly journals Purification efficiency of zeolite and two planted grasses on sewage and relationship with carbon-nitrogen-phosphorus ratios in simulated constructed wetland system

2018 ◽  
Vol 78 (3) ◽  
pp. 545-555
Author(s):  
Xia Liu ◽  
Guohui Ning ◽  
Jianzhi Xie ◽  
Chunjing Liu ◽  
Ming Li
Keyword(s):  
Total Phosphorus ◽  
Rural Areas ◽  
Oxygen Demand ◽  
Volume Ratio ◽  
Ammonia Nitrogen ◽  
Domestic Sewage ◽  
Removal Rates ◽  
Pollutant Concentrations ◽  
Positive Correlations ◽  
C:P Ratios

Abstract For achieving the economical and efficient configuration of constructed wetlands (CWs), a simulated device of vertical flow CWs was used to investigate the effects of different volume ratios of substrates to two cold-resistant plants on pollutant concentrations as well as their ratios in effluent under different inflow domestic sewage concentrations. The average removal rates (ARRs) of ammonia nitrogen, total nitrogen (TN) and total phosphorus were 82.7%, 84.9% and 80.6% respectively in the treatments with zeolite but no plants, which increased by 22.6%, 20.8% and 14.9% compared with those without zeolite and plants. However, in the treatments with zeolite and planted grasses, the ARRs of the three pollutants were over 90%, and those of chemical oxygen demand were lower. The removal rates of ammonia nitrogen, TN and total phosphorus had negative correlations with C:N and N:P ratios and positive correlations with the C:P ratios. Increasing the ratio of zeolite to soil from 1:1 to 2:1 had no significant effects in the removal efficiency. It was suggested that planting Lolium perenne or Poa annua on the substrate with a zeolite to soil volume ratio of 1:1 could be considered as the optimum combination to purify the domestic sewage in north rural areas of China.

scholarly journals Study on the Decontamination Effect of Biochar-Constructed Wetland under Different Hydraulic Conditions

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 893
Author(s):  
Chuanjie Xing ◽  
Xiangxi Xu ◽  
Zhenghe Xu ◽  
Rongzhen Wang ◽  
Lirong Xu
Keyword(s):  
Chemical Oxygen Demand ◽  
Constructed Wetlands ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Constructed Wetland ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Removal Rates ◽  
Hydraulic Conditions ◽  
Hydraulic Load

To explore the purification effect of biochar-constructed wetlands on rural domestic sewage, six types of biochar-constructed wetlands were constructed for experiments. Under different hydraulic conditions, the removal effects of each biochar-constructed wetland on chemical oxygen demand, ammonia nitrogen, total nitrogen, and total phosphorus in sewage were analyzed. The results showed that the removal rates of the four types of pollutants in each biochar-constructed wetland first increased and then decreased with the increase in hydraulic retention time, and the optimal hydraulic retention time range was 36–48 h. The highest removal rates of chemical oxygen demand, ammonia nitrogen, total nitrogen, and total phosphorus in the wetland were 97.34 ± 0.84%, 95.44 ± 1.29%, 98.95 ± 0.52%, and 97.78 ± 0.91%, respectively. The chemical oxygen demand (COD) removal rate of each biochar-constructed wetland increased first, then decreased with the increase in hydraulic load, and the optimal hydraulic load was 10 cm/d. The removal efficiency of ammonia nitrogen, total nitrogen, and total phosphorus of each biochar-constructed wetland gradually weakened with the increase in hydraulic load, and the optimal hydraulic load range was between 5 and 10 cm/d. Under these conditions, the highest removal rates of chemical oxygen demand, ammonia nitrogen, total nitrogen, and total phosphorus in the wetland were 92.15 ± 2.39%, 98.32 ± 0.48%, 96.69 ± 1.26%, and 92.62 ± 2.92%, respectively. Coconut shell and shell-constructed wetlands with the highest proportion of biochar in the matrix have the best removal effect on pollutants under different hydraulic conditions, and the wastewater purification effect is stronger, indicating that the addition of biochar is helpful for the removal of pollutants in constructed wetlands.

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.

Quantitative Eco-Compensation Criterion in Taihu Lake Area of Jiangsu Province, China

2013 ◽  
Vol 726-731 ◽  
pp. 4095-4100
Author(s):  
Rong Rong Xie ◽  
Yong Pang
Keyword(s):  
Chemical Oxygen Demand ◽  
Total Phosphorus ◽  
Taihu Lake ◽  
Census Data ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Pollution Source ◽  
Jiangsu Province ◽  
Lake Area ◽  
Chinese Yuan

To redress the deteriorating environment, policies regarding river eco-compensation have been issued in China since 2008. Due to the high cost, eco-compensation has not been well implemented in the Taihu pilot region. Therefore, how to determine the compensation criterion is already a priority. In this paper, a compensation criterion model based on the treatment costs of sewage was introduced. Using the pollution source census data covering 2007, 2009, 2010 and 2011 in the Taihu lake area of Jiangsu province, the average eco-compensation criterion for chemical oxygen demand (COD) is 2,000 Chinese Yuan (CNY) ± 325 CNY per ton and ammonia nitrogen (NH4-N) and total phosphorus (TP) are 8,000 CNY ± 1,300 CNY and 80,000 CNY ± 13,000 CNY per ton, respectively. The new method can provide an important template for managers when drafting river eco-compensation schemes.

scholarly journals Isolation and degradation characteristics of bacteria in black and odorous water

2021 ◽  
Author(s):  
Hao Yuan ◽  
Gangcai Chen ◽  
Yuchun Xiao ◽  
Jianxia Yang ◽  
Liping Huang ◽  
...  
Keyword(s):  
Oxygen Demand ◽  
Volume Ratio ◽  
Ammonia Nitrogen ◽  
Overlying Water ◽  
Bacterial Agent ◽  
Functional Bacteria ◽  
Final Compound ◽  
Treatment Technologies ◽  
Optimized Conditions

Abstract Bioremediation is one of the treatment technologies for the black-odorous water, and obtaining functional bacteria is the key step to its success. In this study, a number of highly efficient pollutant degrading strains were isolated from the sediment of black-odorous river, and were identified by phenotypic and phylogenetic analysis. The composite bacterial agent J1 was mixed by strains A1, A2, A5 and A7, with a volume ratio of 4:4:2:1. And the final compound bacteria injected into black-odorous water were composed of J1 and NS3, with the volume ratio of 1:1. Optimized degradation conditions of compound bacterium agent were as follows: pH 7.5, DO 2.5 mg/L, temperature 30 °C. Under optimized conditions, add 1% by volume to the black-odorous water for a 50-day experimental operation. Finally, the overlying water ammonia nitrogen, chemical oxygen demand (COD), and total phosphorus has been significantly degraded. The research is expected to contribute to the use of bioremediation methods to repair black-odorous water, and the application of isolates can be carried out in-situ for water types similar to pollute waterways.

scholarly journals Effect of the ammonia concentration on the performance of wetland microbial fuel cells

2021 ◽  
Vol 269 ◽  
pp. 01002
Author(s):  
Li Wang ◽  
Jiafeng Fu ◽  
Wenlei Wang ◽  
Yutong Song ◽  
Yan Li
Keyword(s):  
Fuel Cell ◽  
Microbial Fuel Cell ◽  
Microbial Fuel Cells ◽  
Nitrogen Concentration ◽  
Oxygen Demand ◽  
Ammonia Concentration ◽  
Ammonia Nitrogen ◽  
Internal Resistance ◽  
Removal Rates ◽  
Fixed Condition

This work explores the effect of the ammonia concentration on the wetland synthesis of microbial fuel cell (MFC) and on the production and the efficiency of sewage purification. Four ammonia concentrations from 1 to 30 mg/L have been selected. Under the fixed condition of a chemical oxygen demand (COD) concentration of 200 mg/L, a constructed wetland microbial fuel cell (CW-MFC) could be built. The results show that by selecting the optimum ammonia concentration the production of the CW-MFC could be promoted; a higher ammonia concentration (>20 mg/L) is found to inhibit the production activity of CW-MFC. In the optimum conditions, Cathode and anode thickness is 10 cm, the ammonia concentration is 10 mg/L, the COD concentration of 200 mg/L, the maximum power density of the battery is 13.6 W/m3, the corresponding current density is 148.6 A/m3 and the battery internal resistance is 270 Ω. At the ammonia nitrogen concentration of 10 mg/L, the removal rates of ammonia nitrogen and COD were up to 89.7% and 98.47% respectively. As the ammonia nitrogen concentration increased to 30 mg/L, the ammonia nitrogen and COD removal rates decreased to 74.6% and 90.69% respectively. That is, when the ammonia nitrogen concentration is 10 mg/L, CW-MFC can exhibit the best performance.

Productive Experiment of Combined Process Treating Sewage of Three Gorges Reservoir Region

2011 ◽  
Vol 90-93 ◽  
pp. 2444-2450
Author(s):  
Xiao Xia Ma ◽  
Lei Huang ◽  
Jing Song Guo
Keyword(s):  
Three Gorges Reservoir ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Domestic Sewage ◽  
Three Gorges ◽  
Removal Rates ◽  
Combined Process ◽  
Effluent Concentration ◽  
Three Gorges Reservoir Region ◽  
The Impact

To investigate the domestic sewage treatment processes fitting for small mountain towns in Three Gorges Reservoir Region, a demonstration project was built to treat domestic sewage which combined with anaerobic hydrolysis, natural water-dropping aeration and improved artificial soil rapid infiltration and was based on the features of large terrain elevation and many barren ravines. Changes of major pollutants were analyzed in the combined process. The impact of temperature and influent loadings on removal rates of pollutants was investigated. The results showed that, the treatment system had a strong resistance to the influent loadings with good removal rates of pollutants. There was a relationship between temperature and the removal rates of chemical oxygen demand, ammonia and total nitrogen in the system, where the removal rate of total phosphorus was not associated with temperature. There was a clear linear relationship between effluent concentration and influent loadings, effluent concentration increased with influent loadings. There were approximate logarithmic relationships between removal loadings per unit area and influent loadings.

Study on Simultaneous Nitrification–Denitrification in Membrane Bioreactor

2011 ◽  
Vol 347-353 ◽  
pp. 1878-1882
Author(s):  
Lu Xin ◽  
Kai Sun
Keyword(s):  
Retention Time ◽  
Membrane Bioreactor ◽  
Hydraulic Retention Time ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Suspended Solid ◽  
Domestic Sewage ◽  
Membrane Bioreactors ◽  
Mixed Liquor Suspended Solid ◽  
Do Concentration

This study was conducted to evaluate the performance of membrane bioreactors (MBR) for organics and nitrogen removal. The membrane bioreactor was fed with domestic sewage and operated at different contents of dissolved oxygen (DO), different hydraulic retention time (HRT), and various mixed liquor suspended solid (MLSS) concentrations. The results showed that the distribution of DO level in MBR imposed a significant effect on simultaneous nitrification–denitrification (SND), and the optimal DO concentration should be controlled between 0.5 mg/L to1 mg/L. The denitrification was found to show the best performance for total nitrogen (TN) removal when the HRT reached 5 hours. Higher MLSS concentration led to the improvement in TN removal and the optimal MLSS concentration was 9000mg/L. In fact, more than 90% Chemical Oxygen Demand (COD) and ammonia nitrogen (NH3-N) were reduced when the MLSS concentration exceeded 3000mg/L.

COD and NH4-N Removal in Two-Stage Batch-Flow Constructed Wetland

2013 ◽  
Vol 448-453 ◽  
pp. 604-607 ◽  
Author(s):  
Hong Jie Sun ◽  
Xin Nan Deng ◽  
Rui Chen
Keyword(s):  
Constructed Wetland ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Pilot Scale ◽  
Ammonia Nitrogen ◽  
Two Stage ◽  
Removal Rates ◽  
N Removal ◽  
Domestic Wastewater Treatment

Research was conducted on pilot-scale, two-stage batch-flow constructed wetland systems for domestic wastewater treatment. Synthetic domestic wastewater was treated in a pre-acidification reactor with a hydraulic retention time (HRT) of 3 hours and the average removal rate of chemical oxygen demand (COD) and ammonia-nitrogen (NH4-N) reached 30% and 13.6%, respectively. The first-stage constructed wetland operated with up-flow and batch feed and drain. One cycle was 12h, including 6h feed and 6h drain. With HRT of 3 days, the effluent COD concentrations fluctuated from 32.5 mg/L to 103.4 mg/L, removal rates varied from 60% to 88%; effluent NH4-N concentrations were in the range of 4.8 mg/L to 10.8 mg/L, removal rates varied from 50% to 70%. The second-stage constructed wetland operated with down-flow, which one cycle was 24h, including 12h feed and 12h drain. With HRT of 1 day, effluent COD concentrations varied from 15.7 mg/L to 48.7 mg/L, removal averaged 53.2%; effluent NH4-N concentrations ranged from 0 mg/L to 0.4 mg/L, average removal exceeded 99%. The spatial variation of COD and NH4-N in the first-stage constructed wetland demonstrated that entrainment of air during draining of constructed wetland could strengthen the removal of COD and NH4-N. Temperature had no significant effect on COD degradation while obviously affected the removal of NH4-N.

Feasibility Study of Municipal Wastewater Treatment by a Subsurface Infiltration System in Northeast, China

2012 ◽  
Vol 610-613 ◽  
pp. 1774-1777
Author(s):  
Hai Bo Li ◽  
Ying Hua Li ◽  
Xin Wang ◽  
Tie Heng Sun
Keyword(s):  
Surface Water ◽  
Northeast China ◽  
Suspended Solids ◽  
Municipal Wastewater ◽  
Oxygen Demand ◽  
Surface Water Quality ◽  
Ammonia Nitrogen ◽  
Domestic Sewage ◽  
Municipal Wastewater Treatment ◽  
Surface Water Pollution

From October 2009 to September 2010, this study focused on investigation the performance of a subsurface wastewater infiltration (SWI) system in treating domestic sewage, and evaluated the potential of the surface water pollution by using the SWI system. The results showed the removal efficiencies were relatively high: for biochemical oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS), ammonia nitrogen (NH3-N) and total phosphorus (TP) were 95.0, 89.1, 98.1 87.6 and 98.4%, respectively. Meanwhile, the monitoring of a nearby stream characteristic indicated the SWI system could not decrease the receiving surface water quality.

Effect of earthworm loads on organic matter and nutrient removal efficiencies in synthetic domestic wastewater, and on bacterial community structure and diversity in vermifiltration

2013 ◽  
Vol 68 (1) ◽  
pp. 43-49 ◽  
Author(s):  
L. M. Wang ◽  
X. Z. Luo ◽  
Y. M. Zhang ◽  
J. J. Lian ◽  
Y. X. Gao ◽  
...  
Keyword(s):  
Organic Matter ◽  
Community Structure ◽  
Bacterial Community ◽  
Bacterial Community Structure ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Ammonia Nitrogen ◽  
Domestic Sewage ◽  
Shannon Index

In this paper, we studied the effect of earthworm loads on the removal rates of chemical oxygen demand (COD), ammonia nitrogen (NH3-N), total nitrogen, and total phosphorus from synthetic domestic sewage and on the bacterial community structure and diversity of substrates in earthworm packing beds. The different vermifiltrations (VFs), including the control, are successful in removing both organic matter (OM) and nutrients. The removal rate of NH3-N at 12.5 g of earthworm/L of soil VF is higher compared with that at 0 and 4.5 earthworm load VFs. The highest Shannon index, in the earthworm packing bed, occurred at 16.5 earthworm load VF. Furthermore, the COD removal rate is significantly correlated with the Shannon index, which reveals that OM removal for synthetic domestic sewage treatment at VF might be more dependent on bacterial diversity at the earthworm packing bed. The band distributions and diversities of the bacterial community for samples from different earthworm loads in VFs suggest that the bacterial community structure was only affected within the earthworm packing bed when the earthworm load reached a certain level. The present study adds to the current understanding of OM and nutrient degradation processes in VF domestic wastewater treatment.

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