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.

scholarly journals Effect of hydraulic retention time on chemical oxygen demand and total nitrogen removal in intermittently aerated constructed wetlands

2020 ◽  
Vol 15 (3) ◽  
pp. 1 ◽  
Author(s):  
Isabela Pires da Silva ◽  
Gabriela Barbosa da Costa ◽  
João Gabriel Thomaz Queluz ◽  
Marcelo Loureiro Garcia
Keyword(s):  
Chemical Oxygen Demand ◽  
Constructed Wetlands ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Constructed Wetland ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Subsurface Flow ◽  
Oxygen Demand ◽  
Intermittent Aeration

   This study evaluated the effect of hydraulic retention time on chemical oxygen demand (COD) and total nitrogen (TN) removal in an intermittently aerated constructed wetlands. Two horizontal subsurface-flow constructed wetlands were used: one without aeration and the other aerated intermittently (1 hour with aeration/7 hours without aeration). Both systems were evaluated treating domestic wastewater produced synthetically. The flow rate into the two CWs was 8.6 L day-1 having a hydraulic retention time of 3 days. The results show that the intermittently aerated constructed wetland were highly efficient in removing COD (98.25%), TN (83.60%) and total phosphorus (78.10%), while the non-aerated constructed wetland showed lower efficiencies in the removal of COD (93.89%), TN (48.60%) and total phosphorus (58.66). These results indicate, therefore, that intermittent aeration allows the simultaneous occurrence of nitrification and denitrification processes, improving the removal of TN in horizontal subsurface-flow constructed wetlands. In addition, the use of intermittent aeration also improves the performance of constructed wetlands in removing COD and total phosphorus.

Influence of earthworm Eisenia fetida on Iris pseudacorus's photosynthetic characteristics, evapotranspiration losses and purifying capacity in constructed wetland systems

2013 ◽  
Vol 68 (2) ◽  
pp. 335-341 ◽  
Author(s):  
Defu Xu ◽  
Yingxue Li ◽  
Xiaolong Fan ◽  
Yidong Guan ◽  
Hua Fang ◽  
...  
Keyword(s):  
Chemical Oxygen Demand ◽  
Bulk Density ◽  
Removal Efficiency ◽  
Constructed Wetlands ◽  
Total Nitrogen ◽  
Negative Correlation ◽  
Constructed Wetland ◽  
Transpiration Rate ◽  
Eisenia Fetida ◽  
Oxygen Demand

Four constructed wetland systems were studied to investigate the effects of adding Eisenia fetida on the purifying capacity of constructed wetlands. Addition of E. fetida increased the photosynthetic rate (Pn), transpiration rate (Tr) and chlorophyll meter value of leaves of Iris pseudacorus L. in the constructed wetlands by 16, 35 and 7%, respectively. Compared with the substrate only system, evapotranspiration losses were increased by 8, 48 and 56% for the wetland systems with substrate and E. fetida, with substrate and I. pseudacorus, and with substrate, I. pseudacorus and E. fetida, respectively. Addition of E. fetida to the substrate only and substrate and plant wetland systems decreased the substrate bulk density by 3 and 6%, respectively. The addition of E. fetida to the system with substrate and plants increased the removal efficiency of chemical oxygen demand (CODMn), total nitrogen (TN) and total phosphorus by 5, 7 and 22%, respectively. Evapotranspiration losses were significantly positively correlated with the removal efficiency of CODMn (P < 0.01). The significantly negative correlation between the removal efficiency TN and bulk density was found (P < 0.05). Therefore, E. fetida could stimulate I. pseudacorus growth and improve the substrate bulk density in the constructed wetland, resulting in enhanced purifying capacity.

scholarly journals Analysis and investigation of the third drainage ditch pollution situation in Ningxia based on multivariate statistics

2020 ◽  
Vol 145 ◽  
pp. 02082
Author(s):  
Linfeng Tian
Keyword(s):  
Chemical Oxygen Demand ◽  
Multivariate Statistics ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Water Environment ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Drainage Ditch ◽  
The Third ◽  
Social Statistics

This article takes the third drainage ditch in Ningxia as the research object, and uses the multivariate statistics method to analyze the interrelationship between the four major pollutants at nine regional points in the main pollution ditch section of the third drainage ditch throughout the year from the perspective of time and space, to improve the water environment quality. SPSS (Social Statistics Software Package) is used to analyze chemical oxygen demand, total phosphorus, total nitrogen, ammonia nitrogen, and index of major pollutants of permanganate. The research results show that the main pollutants and the degree of pollution affecting the water quality of the third drainage ditch are: total nitrogen> ammonia nitrogen> total phosphorus> chemical oxygen demand. At the end of San’er, ammonia nitrogen and total nitrogen were the most polluted. At the Dawukou section of San’er, the chemical oxygen demand and total phosphorus were the heaviest.

scholarly journals Digestate Liquid Fraction Treatment with Filters Filled with Recovery Materials

Water ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 21
Author(s):  
Ilaria Piccoli ◽  
Giuseppe Virga ◽  
Carmelo Maucieri ◽  
Maurizio Borin
Keyword(s):  
Chemical Oxygen Demand ◽  
Total Nitrogen ◽  
Liquid Fraction ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Green Technology ◽  
Filling Material ◽  
Community Interactions ◽  
Material Particle ◽  
N Removal

Constructed wetlands (CWs) represent a green technology for digestate liquid fraction (DLF) treatment. However, previous research has warned about their performance when treating wastewater with high suspended solid and organic loads. In addition, the high NH4-N concentration typical of this wastewater can compromise vegetation establishment and activity. In view of this, a digestate pretreatment is needed. This study aimed to test the performance of filters filled with recovery materials, such as brick and refractory material, for DLF pretreatment. The effect on DLF physical (electrical conductivity, pH, dissolved oxygen, and temperature) and chemical (total nitrogen, ammonia–nitrogen, nitrate–nitrogen, total phosphorus, soluble phosphorus, and chemical oxygen demand) characteristics was monitored during eight weekly cycles. The effect of filtration on total nitrogen and ammonia–nitrogen removal began after about one month of loading, suggesting that an activation period is necessary for bacteria. For effective N removal, the presence of multiple digestate recirculations per day through the filters appears mandatory to guarantee the alternation of nitrification and denitrification conditions. For P removal, filling material particle size appeared to be more important than its composition. Unclear performances were observed considering chemical oxygen demand. Further studies on filling media and microbial community interactions, and the long-term efficiency of filters, are desirable.

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 The Efficiency and Reliability of Pollutant Removal in a Hybrid Constructed Wetland with Common Reed, Manna Grass, and Virginia Mallow

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1445 ◽  
Author(s):  
Michał Marzec ◽  
Krzysztof Jóźwiakowski ◽  
Anna Dębska ◽  
Magdalena Gizińska-Górna ◽  
Aneta Pytka-Woszczyło ◽  
...  
Keyword(s):  
Total Nitrogen ◽  
Total Phosphorus ◽  
Constructed Wetland ◽  
Suspended Solids ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Total Suspended Solids ◽  
Common Reed ◽  
Pollutant Removal ◽  
Limit Values

In this paper, the pollutant removal efficiency and the reliability of a vertical and horizontal flow hybrid constructed wetland (CW) planted with common reed, manna grass, and Virginia mallow were analyzed. The wastewater treatment plant, located in south-eastern Poland, treated domestic sewage at an average flow rate of 2.5 m3/d. The tests were carried out during five years of its operation (2014–2018). The following parameters were measured: biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total suspended solids, total nitrogen, and total phosphorus. The results showed that more than 95% of BOD5, COD, and total phosphorus was removed in the tested CW system. The average effectiveness of removal of total suspended solids and total nitrogen exceeded 86%. A reliability analysis performed using the Weibull probability model showed that the removal reliability in the tested CW was very high for BOD5, COD, total suspended solids, and total phosphorus (100%). The probability that the total nitrogen concentration in the treated effluents would reach the limit value (30 mg/L) established for effluents discharged from a treatment plant of less than 2000 PE (population equivalent) to standing waters was 94%. The values of all the pollution indicators in wastewater discharged to the receiver were significantly lower than the limit values required in Poland. The investigated hybrid CW system with common reed, manna grass, and Virginia mallow guaranteed stable low values of BOD5, COD, total suspended solids, and total phosphorus in the treated wastewater, which meant it was highly likely to be positively evaluated in case of an inspection.

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.

Enhanced denitrification with external carbon sources in a biological anoxic filter

2012 ◽  
Vol 66 (10) ◽  
pp. 2243-2250 ◽  
Author(s):  
Wen-yi Dong ◽  
Xian-bing Zhang ◽  
Hong-jie Wang ◽  
Fei-yun Sun ◽  
Tong-zhou Liu
Keyword(s):  
Chemical Oxygen Demand ◽  
Total Nitrogen ◽  
Biomass Yield ◽  
Nitrate Nitrogen ◽  
Carbon Sources ◽  
Oxygen Demand ◽  
Brewery Wastewater ◽  
Removal Rates ◽  
Denitrification Kinetics ◽  
Kinetics Of

Three parallel biological anoxic filters (BaFs) were operated to investigate the denitrification kinetics of methanol, brewery wastewater and bakery wastewater. The experiment was conducted within the temperature range of 15–20 °C, with an influent nitrate and carbon dosage of 30 mg/L and 150 mg COD/L (COD: chemical oxygen demand). The denitrification efficiencies of brewery wastewater, bakery wastewater and methanol were 84, 66 and 74%, specific denitrification rates were 1.44, 1.11 and 1.24 kg NO3-N/m3 d, and total nitrogen (TN) removal rates were 74, 62 and 66%, respectively. The volatile attached solid (VAS) tests reveal that methanol has the minimum net biomass yield, so it needs the least carbon to nitrogen (expressed in COD to nitrate, C/N) ratio for complete denitrification. While the brewery wastewater and bakery wastewater need higher C/N ratio to remove all nitrate nitrogen, and they both may need pretreatment to remove phosphate when used as external carbon sources.

scholarly journals Preparation of Ceramsite Based on Waterworks Sludge and Its Application as Matrix in Constructed Wetlands

2019 ◽  
Vol 16 (15) ◽  
pp. 2637 ◽  
Author(s):  
Yaning Wang ◽  
Jinhu Yang ◽  
Hang Xu ◽  
Chenwei Liu ◽  
Zhen Shen ◽  
...  
Keyword(s):  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Average Pore Size ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Land Resources ◽  
Average Pore ◽  
Start Up ◽  
Denitrifying Microorganisms ◽  
Waterworks Sludge

The recycling of waterworks sludge has become a trending issue because it not only solves the problem of difficult disposal but also saves land resources. This paper aimed to provide a new idea for the utilization of waterworks sludge to form ceramsite and to purify sewage. The specific surface area, average pore size, and pore volume of the made ceramsite were 8.15 m2/g, 8.53 nm, and 1.88 cm2/g, respectively. The made ceramsite was applied in a vertical-flow constructed wetland, and the removal efficiency of nitrogen, phosphorus and organic matter in sewage were investigated under the conditions of different start-up periods, hydraulic retention times, matrix filling heights and water quality. The removal rates of chemical oxygen demand (COD), ammonia nitrogen (NH3-N), and total phosphorus (TP) in the constructed wetlands were stable at 70%, 60%, and 79%, respectively. This constructed wetland with a ceramic matrix has certain advantages in the total amount of denitrifying microorganisms, with a proportion of 14.92%. The results prove the feasibility of preparing ceramsite from waterworks sludge and applying it as a matrix in a constructed wetland to purify sewage.

Performance of a baffled facultative pond treating piggery wastes

2002 ◽  
Vol 45 (1) ◽  
pp. 49-53 ◽  
Author(s):  
C.T. Zanotelli ◽  
W. Medri ◽  
P. Belli Filho ◽  
C.C. Perdomo ◽  
M.R. Mulinari ◽  
...  
Keyword(s):  
Chemical Oxygen Demand ◽  
Removal Efficiency ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Oxygen Demand ◽  
Faecal Coliforms ◽  
The West ◽  
West Region ◽  
Removal Efficiencies ◽  
Water Hyacinths

This paper shows the performance of a baffled facultative pond for the treatment of piggery wastes. The full-scale system is composed of an equalizer, one decanter (DP), two anaerobic ponds (LA1 and LA2), one facultative pond (LF), with five baffles, and one maturation pond with water hyacinths (LAG). The studies were conducted over a 12 month period in the west region of Santa Catarina, Brazil. The system was supplied daily with a volume of 3 m3/day of farm wastes. A good performance of the treatment system was obtained with average removal efficiencies of 98% for chemical oxygen demand, 93% for total solids, 98% for total phosphorus, 92% for total nitrogen, 7 log units of faecal coliforms and 5 log units of total coliforms. The facultative pond performed well, removing 43% of the chemical oxygen demand, 47% of total nitrogen and 54% of total phosphorus. It was found that the first baffle in the facultative pond was mainly responsible for the efficiency of this pond, and compared with another study the introduction of the baffles improved the removal efficiency by 20% for total phosphorus.

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