Nutrients Removal from Secondary Effluent by Using Different Constructed Wetland Systems

2012 ◽  
Vol 518-523 ◽  
pp. 2155-2160
Author(s):  
Xue Min Xiang ◽  
Xiao Bai Zhou ◽  
Xiao Kun Wang ◽  
Ji Ti Zhou ◽  
Ren Wang
Keyword(s):  
Constructed Wetland ◽  
Removal Rate ◽  
Feeding Strategy ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Control Treatment ◽  
Feeding Strategies ◽  
Secondary Effluent ◽  
Intermittent Feeding ◽  
Multi Stage

Constructed wetland was recognized as an economic and ecological-friendly technique to reduce excess nitrogen (N) and phosphorus (P) in secondary effluent from sewage treatment plants. In this study, the removal capacity of non-planted control treatment, one stage constructed wetland with different feeding strategies, and multi-stage constructed wetland on chemical oxygen demand (COD), total nitrogen (TN), ammonia nitrogen (NH4+-N) and total phosphorus (TP)were evaluated. The results showed that all the planted treatments displayed superior removal efficiency for COD and nutrients in compare with the non-planted control treatment. The feeding strategy could influence COD andN removal rate that the averageremoval rate of the COD, TN, and NH4+-N in intermittent feeding treatment (61.3%, 52.6% and 88.7%) was much higher than continuous feeding treatment (46.8%, 20.6% and 73.9%). Higher TN and TP removal rate was observed in multi-stage constructed wetland (74.1% and 98.1%) than the single-stage constructed wetland (20.6% and 96.9%). This implied that intermittent feeding strategy and the multi-stage constructed wetland may have a good potential for removing nutrients from secondary effluent.

scholarly journals Purification Effect of Sequential Constructed Wetland for the Polluted Water in Urban River

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1054 ◽  
Author(s):  
Xueyuan Bai ◽  
Xianfang Zhu ◽  
Haibo Jiang ◽  
Zhongqiang Wang ◽  
Chunguang He ◽  
...  
Keyword(s):  
Constructed Wetland ◽  
Removal Rate ◽  
Sewage Treatment ◽  
Oxygen Demand ◽  
Ecological Engineering ◽  
Ammonia Nitrogen ◽  
Surface Flow ◽  
Urban River ◽  
Polluted Water ◽  
Urban Rivers

Constructed wetlands can play an active role in improving the water quality of urban rivers. In this study, a sequential series system of the floating-bed constructed wetland (FBCW), horizontal subsurface flow constructed wetland (HSFCW), and surface flow constructed wetland (SFCW) were constructed for the urban river treatment in the cold regions of North China, which gave full play to the combined advantages. In the Yitong River, the designed capacity and the hydraulic loading of the system was 100 m3/d and 0.10 m3/m2d, respectively. The hydraulic retention time was approximately 72 h. The monitoring results, from April to October in 2016, showed the multiple wetland ecosystem could effectively remove chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), total nitrogen (TN), total phosphate (TP), and suspended solids (SS) at average removal rates of 74.79%, 80.90%, 71.12%, 78.44%, and 91.90%, respectively. The removal rate of SS in floating-bed wetland was the largest among all the indicators (80.24%), which could prevent the block of sub-surface flow wetland effectively. The sub-surface flow wetland could remove the NH4-N, TN, and TP effectively, and the contribution rates were 79.20%, 64.64%, and 81.71%, respectively. The surface flow wetland could further purify the TN and the removal rate of TN could reach 23%. The total investment of this ecological engineering was $12,000. The construction cost and the operation cost were $120 and $0.02 per ton of polluted water, which was about 1/3 to 1/5 and 1/6 to 1/3 of the conventional sewage treatment, respectively. The results of this study provide a technical demonstration of the restoration of polluted water in urban rivers in northern China.

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.

Performance and metabolic aspects of a novel enhanced biological phosphorus removal system with intermittent feeding and alternate aeration

2013 ◽  
Vol 69 (8) ◽  
pp. 1612-1619 ◽  
Author(s):  
Paraschos Melidis ◽  
Anastasios G. Kapagiannidis ◽  
Spyridon Ntougias ◽  
Konstantina Davididou ◽  
Alexander Aivasidis
Keyword(s):  
Phosphorus Removal ◽  
Feeding Strategy ◽  
Oxygen Demand ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Intermittent Feeding ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
On Line ◽  
Biological Phosphorus

A novel enhanced biological phosphorus removal (EBPR) system, which combined the intermittent feeding design with an anaerobic selector, was examined using on-line oxidation reduction potential (ORP), nitrate and ammonium probes. Two experimental periods were investigated: the aerobic and anoxic phases were set at 40 and 20 minutes respectively for period I, and set at 30 and 30 minutes for period II. Chemical oxygen demand (COD), biochemical oxygen demand (BOD5) and P removal were measured as high as 87%, 96% and 93% respectively, while total Kjeldahl nitrogen (TKN) and NH4+ removal averaged 85% and 91%. Two specific denitrification rates (SDNRs), which corresponded to the consumption of the readily biodegradable and slowly biodegradable COD, were determined. SDNR-1 and SDNR-2 during period I were 0.235 and 0.059 g N g−1 volatile suspended solids (VSS) d−1 respectively, while the respective rates during period II were 0.105 and 0.042 g N g−1 VSS d−1. The specific nitrate formation and ammonium oxidizing rates were 0.076 and 0.064 g N g−1 VSS d−1 for period I and 0.065 and 0.081 g N g−1 VSS d−1 for period II respectively. The specific P release rates were 2.79 and 4.02 mg P g−1 VSS h−1 during period I and II, while the respective anoxic/aerobic uptake rates were 0.42 and 0.55 mg P g−1 VSS h−1. This is the first report on an EBPR scheme using the intermittent feeding strategy.

scholarly journals In Situ Nutrient Removal from Rural Runoff by A New Type Aerobic/Anaerobic/Aerobic Water Spinach Wetlands

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1100 ◽  
Author(s):  
Ya-Wen Wang ◽  
Hua Li ◽  
You Wu ◽  
Yun Cai ◽  
Hai-Liang Song ◽  
...  
Keyword(s):  
Nitrogen Removal ◽  
Constructed Wetland ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Ammonium Nitrogen ◽  
Water Spinach ◽  
Nitrogen And Phosphorus ◽  
The Matrix ◽  
New Type ◽  
Nitrification And Denitrification

Rural runoff with abundant nutrients has become a great threat to aquatic environment. Hence, more and more attention has been focused on nutrients removal. In this study, an improved aerobic/anaerobic/aerobic three-stage water spinach constructed wetland (O-A-O-CW) was used to improve the removal of nitrogen and phosphorus of rural runoff. The removal rate of the target pollutants in O-A-O-CW was compared with the common matrix flow wetland as well as the no-plant wetland. The results showed that the O-A-O-CW significantly increased the chemical oxygen demand, total phosphorus, ammonium-nitrogen, nitrate, and total nitrogen removal rate, and the corresponding removal rate was 55.85%, 81.70%, 76.64%, 89.78%, and 67.68%, respectively. Moreover, the best hydraulic condition of the wetland, including hydraulic retention time and hydraulic loading, was determined, which were 2 days and 0.45 m3·m−2·day−1, respectively. Furthermore, the removal mechanism of the constructed wetland was thoroughly studied, which included the adsorption of nitrogen and phosphorus by the matrix and water spinach, and the nitrification and denitrification by the bacteria. The results demonstrated that the mechanisms of nitrogen removal in the new type wetland were principally by the nitrification and denitrification process. Additionally, adsorption and precipitation by the matrix are mainly responsible for phosphorus removal. These results suggested that the new O-A-O-CW can efficiently removal nutrients and enhance the water quality of the rural runoff.

scholarly journals Combined Application of UV Photolysis and Ozonation with Biological Aerating Filter in Tertiary Wastewater Treatment

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Zhaoqian Jing ◽  
Shiwei Cao
Keyword(s):  
Molecular Weight ◽  
Wastewater Treatment ◽  
Organic Pollutants ◽  
Wastewater Treatment Plants ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Secondary Effluent ◽  
Uv Photolysis ◽  
Combined Application

To enhance the biodegradability of residual organic pollutants in secondary effluent of wastewater treatment plants, UV photolysis and ozonation were used in combination as pretreatment before a biological aerating filter (BAF). The results indicated that UV photolysis could not remove much COD (chemical oxygen demand), and the performance of ozonation was better than the former. With UV photolysis combined with ozonation (UV/O3), COD removal was much higher than the sum of that with UV photolysis and ozonation alone, which indicated that UV photolysis could efficiently promote COD removal during ozonation. This pretreatment also improved molecular weight distribution (MWD) and biodegradability greatly. Proportion of organic compounds with molecular weight (MW) <3 kDalton was increased from 51.9% to 85.9%. COD removal rates with BAF and O3/BAF were only about 25% and 38%, respectively. When UV/O3oxidation was combined with BAF, the average COD removal rate reached above 61%, which was about 2.5 times of that with BAF alone. With influent COD ranging from 65 to 84 mg/L, the effluent COD was stably in the scope of 23–31 mg/L. The combination of UV/O3oxidation with BAF was quite efficient in organic pollutants removal for tertiary wastewater treatment.

Effects of Hydraulic Loading Rate on Nutrient Removal in Multi-Stage Constructed Wetland

2013 ◽  
Vol 864-867 ◽  
pp. 1498-1502
Author(s):  
Qing Feng Chen ◽  
Wen Guo Dong ◽  
Jun Jian Ma ◽  
Qing Li ◽  
Xin Guo Gao ◽  
...  
Keyword(s):  
Constructed Wetland ◽  
Loading Rate ◽  
Optimal Parameter ◽  
Removal Rate ◽  
Operational Parameter ◽  
Hydraulic Loading Rate ◽  
Hydraulic Loading ◽  
Multi Stage ◽  
Operation Period ◽  
D 12

Hydraulic loading rate (HLR) is an important operational parameter for constructed wetland to purify wastewater. In this paper, it is the main objective to select the optimal parameter of HLR. During the four HLRs (i.e., 6 cm/d, 12 cm/d, 24 cm/d and 48 cm/d) operation period, six days were used as one stage. The experimental results showed that the best average removal rates of CODcr (59.7%) and NH3-N (89.4%) were at the HLR of 6 cm/d. In the meantime, the best average removal rate of total phosphorus (TP, 50.0%) was at the HLR of 24 cm/d. According to the low influent TP concentration, it is suggested that the HLR of 6 cm/d should be used in the multi-stage constructed wetland.

scholarly journals Viability of a Single-Stage Unsaturated-Saturated Granular Activated Carbon Biofilter for Greywater Treatment

2020 ◽  
Vol 12 (21) ◽  
pp. 8847
Author(s):  
Ahmed Sharaf ◽  
Bing Guo ◽  
David C. Shoults ◽  
Nicholas J. Ashbolt ◽  
Yang Liu
Keyword(s):  
Activated Carbon ◽  
Removal Rate ◽  
Feeding Strategy ◽  
Oxygen Demand ◽  
Granular Activated Carbon ◽  
Complete Removal ◽  
Single Stage ◽  
Chemical Oxygen Demand Removal ◽  
Over Time ◽  
Sewage Source

Compared with conventionally collected sewage, source-diverted greywater has a higher potential for on-site treatment and reuse due to its lower contaminant levels and large volume. A new design of granular activated carbon (GAC) biofilters was developed by incorporating unsaturated and saturated zones in a single stage to introduce an efficient, passive, and easy-to-operate technology for greywater on-site treatment at the household scale. The design was customized for its intended application considering various aspects including the reactor’s configuration, packing media, and feeding strategy. With the highest hydraulic and organic loadings of 1.2 m3 m−2 d−1 and 3.5 kg COD m−2 d−1, respectively, and the shortest retention time of 2.4 h, the system maintained an average total chemical oxygen demand removal rate of 94% with almost complete removal of nutrients throughout its 253 days of operation. The system showed a range of reduction efficacy towards five surrogates representing viruses, bacteria, and Cryptosporidium and Giardia (oo)cysts. A well-functioning biofilm was successfully developed, and its mass and activity increased over time with the highest values observed at the top layers. The key microbes within the biofilter were revealed. Feasibility of the proposed technology was investigated, and implications for design and operation were discussed.

Treatment of petrochemical secondary effluent by an up-flow biological aerated filter (BAF)

2016 ◽  
Vol 73 (8) ◽  
pp. 2031-2038 ◽  
Author(s):  
L. Y. Fu ◽  
C. Y. Wu ◽  
Y. X. Zhou ◽  
J. E. Zuo ◽  
Y. Ding
Keyword(s):  
Removal Efficiency ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Ammonia Nitrogen ◽  
Gas Chromatography Mass Spectrometry ◽  
Secondary Effluent ◽  
Biological Aerated Filter ◽  
Total Removal ◽  
Aerated Filter ◽  
Final Effluent

In this study, petrochemical secondary effluent was treated by a 55 cm diameter pilot-scale biological aerated filter (BAF) with a media depth of 220 cm. Volcanic rock grains were filled as the BAF media. Median removal efficiency of chemical oxygen demand (COD) and ammonia nitrogen (NH3-N) was 29.35 and 57.98%, respectively. Moreover, the removal profile of the COD, NH3-N, total nitrogen and total organic carbon demonstrated that the filter height of 140 cm made up to 90% of the total removal efficiency of the final effluent. By gas chromatography–mass spectrometry, removal efficiencies of 2-chloromethyl-1,3-dioxolane, and benzonitrile, indene and naphthalene were obtained, ranging from 30.12 to 63.01%. The biomass and microbial activity of the microorganisms on the filter media were in general reduced with increasing filter height, which is consistent with the removal profile of the contaminants. The detected genera Defluviicoccus, Betaproteobacteria_unclassified and the Blastocatella constituted 1.86–6.75% of the identified gene, enhancing the COD and nitrogen removal in BAF for treating petrochemical secondary effluent.

Effect of dosing regime on nitrification in a subsurface vertical flow treatment wetland system

2012 ◽  
Vol 66 (6) ◽  
pp. 1220-1224
Author(s):  
Suwasa Kantawanichkul ◽  
Walaya Boontakhum
Keyword(s):  
Continuous Flow ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Synthetic Wastewater ◽  
Experimental Unit ◽  
Vertical Flow ◽  
Treatment Wetland ◽  
Wetland System ◽  
Flow Treatment

In this study, the effect of dosing regime on nitrification in a subsurface vertical flow treatment wetland system was investigated. The experimental unit was composed of four circular concrete tanks (1 m diameter and 80 cm deep), filled with gravel (1–2 cm) and planted with Cyperus alternifolius L. Synthetic wastewater with average chemical oxygen demand (COD) and ammonia nitrogen of 1,151 and 339 mg/L was fed into each tank. Different feeding and resting periods were applied: continuous flow (tank 1), 4 hrs on and 4 hrs off (tank 2), 1 hr on and 3 hrs off (tank 3) and 15 minutes on and 3 hrs 45 minutes off (tank 4). All four tanks were under the same hydraulic loading rate of 5 cm/day. After 165 days the reduction of total Kjeldahl nitrogen and ammonia nitrogen and the increase of nitrate nitrogen were greatest in tank 4, which had the shortest feeding period, while the continuous flow produced the lowest results. Effluent tanks 2 and 3 experienced similar levels of nitrification, both higher than that of tank 1. Thus supporting the idea that rapid dosing periods provide better aerobic conditions resulting in enhanced nitrification within the bed. Tank 4 had the highest removal rates for COD, and the continuous flow had the lowest. Tank 2 also exhibited a higher COD removal rate than tank 3, demonstrating that short dosing periods provide better within-bed oxidation and therefore offer higher removal efficiency.

Effects of chemical oxygen demand (COD)/N ratios on pollutants removal in the subsurface wastewater infiltration systems with/without intermittent aeration

2016 ◽  
Vol 73 (11) ◽  
pp. 2662-2669 ◽  
Author(s):  
Siyu Song ◽  
Jing Pan ◽  
Shiwei Wu ◽  
Yijing Guo ◽  
Jingxiao Yu ◽  
...  
Keyword(s):  
Chemical Oxygen Demand ◽  
Nitrogen Removal ◽  
Removal Rate ◽  
Oxygen Deficiency ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Intermittent Aeration ◽  
Oxidation Reduction ◽  
The Matrix ◽  
Pollutants Removal

The matrix oxidation reduction potential level, organic pollutants and nitrogen removal performances of eight subsurface wastewater infiltration systems (SWISs) (four with intermittent aeration, four without intermittent aeration) fed with influent chemical oxygen demand (COD)/N ratio of 3, 6, 12 and 18 were investigated. Nitrification of non-aerated SWISs was poor due to oxygen deficiency while higher COD/N ratios further led to lower COD and nitrogen removal rate. Intermittent aeration achieved almost complete nitrification, which successfully created aerobic conditions in the depth of 50 cm and did not change anoxic or anaerobic conditions in the depth of 80 and 110 cm. The sufficient carbon source in high COD/N ratio influent greatly promoted denitrification in SWISs with intermittent aeration. High average removal rates of COD (95.68%), ammonia nitrogen (NH4+-N) (99.32%) and total nitrogen (TN) (89.65%) were obtained with influent COD/N ratio of 12 in aerated SWISs. The results suggest that intermittent aeration was a reliable option to achieve high nitrogen removal in SWISs, especially with high COD/N ratio wastewater.

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