scholarly journals The Potential of Sewage Treatment through Constructed Wetlands in Northeast India: A Critical Review

Author(s):  
Getu Yoka ◽  
Ajay Bharti

The benefits of economical treatment systems and global demand for introducing sustainable way of environmental management, the Constructed Wetlands (CWs) treatment of domestic sewage is rising rapidly all over the globe. The Total nitrogen in the sewage is the summation of Organic Nitrogen, Nitrate Nitrogen, Nitrite Nitrogen and Ammonium Nitrogen. Ammonification, Matrix Adsorption, Nitrification, Denitrification, Plant Uptake and Ammonia Volatilization are the principle involved for total nitrogen removal in the treatment of sewage using CWs. This paper provides a comprehensive review by comparative analysis of effects of type and nature of flow system, wetland structures, types of Macrophyte, removal mechanisms, Aeration, Step-feeding and other key operational parameters and conditions for the enhance removal of total nitrogen in CWs.

2007 ◽  
Vol 55 (11) ◽  
pp. 81-85 ◽  
Author(s):  
M.A. Camargo Valero ◽  
D.D. Mara

A primary maturation pond (M1) was spiked with labelled ammonium chloride (15NH4Cl) to track ammonium transformations associated with algal uptake and subsequent sedimentation. Conventional sampling based on grab samples collected from M1 influent, water column and effluent, and processed for unfiltered and filtered TKN, ammonium, nitrite and nitrate, found low total nitrogen removal (8%) and high ammonium nitrogen removal (90%). Stable isotope analysis of 15N from suspended organic and ammonium nitrogen fractions in M1 effluent revealed that labelled ammonium was mainly found in the organic fraction (69% of the 15N recovered), rather than the inorganic fraction (5%). Algal uptake was the predominant pathway for ammonia removal, even though conditions were favourable for ammonia volatilization (8.9 < pH <10.1 units, 15.2 < temperature <18.8 °C). Total nitrogen was removed by ammonia volatilization at 15 g N/ha d (3%), organic nitrogen sedimentation at 105 g N/ha d (20%), and in-pond accumulation due to algal uptake at 377 g N/ha d (71%). Algal uptake of ammonium and subsequent sedimentation and retention in the benthic sludge, after partial ammonification of the algal organic nitrogen, is thus likely to be the dominant mechanism for permanent nitrogen removal in maturation ponds during warm summer months in England.


1996 ◽  
Vol 33 (7) ◽  
pp. 183-189 ◽  
Author(s):  
Andy Shilton

There is a need to improve the performance of agricultural wastewater stabilization ponds. In particular, a better understanding of the relative importance of the nitrogen removal mechanisms is required. The objective of this study was to quantify the magnitude of ammonia volatilization from a piggery pond in order to determine its significance as a nitrogen removal mechanism. A model of a typical piggery pond was established and sampled for ammonia, TKN, COD and pH. A method was developed to allow the rate of ammonia volatilization to be quantified. The rates of ammonia and total nitrogen removal were established, as were the corresponding COD and pH levels over a series of pond ammonia concentrations. The rate of ammonia volatilization ranged from 355 to 1534 mg/m2.d, increasing with higher concentrations of ammonia and TKN. These rates compared well with volatilization rates from other types of piggery waste disposal. It was concluded that although it is impractical to use ammonia volatilization in its own right to achieve high levels of nitrogen removal, it does make a significant contribution to the overall nitrogen removal potential of a piggery pond system.


2014 ◽  
Vol 955-959 ◽  
pp. 2318-2321
Author(s):  
Dong Yuan

The objective of this work was to evaluate the performances of A lab-scale innovative sequencing batch biofilm reactor (SBBR) to treat domestic wastewater,in which a acryl cylinder (height 200 mm, diameter 70 mm) was equipped and many fiber threads were attached to the surface of the cylinder as the bacteria carrier. No time and volume for settling was required in this system. After one year’s operation, each parameter achieved the wastewater discharged criterion in 2 cycles (4 h). It was found that COD removal efficiency was up to 90% in 3 h, and ammonium nitrogen concentration approached the least value; total nitrogen removal efficiency reached 55%-71%. In this SBBR system simultaneous nitrification and denitrification was completed at the end of 2 cycles.


2015 ◽  
Vol 71 (9) ◽  
pp. 1317-1324 ◽  
Author(s):  
Fei Zhong ◽  
Juan Wu ◽  
Yanran Dai ◽  
Dongfang Xiang ◽  
Shuiping Cheng ◽  
...  

The effects of micro-aeration and substrate selection on domestic sewage treatment performance were explored using three pairs (with or without micro-aeration) of horizontal subsurface flow (HSSF) constructed wetlands (CWs) filled with zeolite, ceramsite or quartz granules. The individual and combined effects of micro-aeration and substrate selection on the purification performance of the experimental-scale HSSF CWs were evaluated. The results showed that micro-aeration significantly increased the treatment efficiencies for chemical oxygen demand, total nitrogen, total phosphorus (TP), ortho-phosphate (PO43−-P) and ammonium nitrogen (NH4+-N) using HSSF CWs, while the substrate selection significantly affected the TP, PO43−-P and NH4+-N removal efficiencies (p < 0.05). A two-way analysis of variance (ANOVA) indicated that there was a significant interaction term (i.e. micro-aeration × substrate selection) for NH4+-N removal (p < 0.05). Among the three substrates, ceramsite was the best substrate for the treatment of domestic sewage using HSSF CWs. Therefore, the results of this study suggest that a ceramsite-filled HSSF CW with micro-aeration could be the optimal configuration for decentralized domestic sewage treatment.


2009 ◽  
Vol 59 (10) ◽  
pp. 1893-1899 ◽  
Author(s):  
W. L. Tsang ◽  
J. Wang ◽  
H. Lu ◽  
S. Li ◽  
G. H. Chen ◽  
...  

This study reports a lab-scale evaluation of a new biological nitrogen removal process for saline sewage treatment, namely a SANI process (Sulfate reduction, Autotrophic denitrification and Nitrification Integrated process). The experimental system consisted of an up-flow anaerobic bed for sulfate reduction, an anoxic filter for autotrophic denitrification using dissolved sulfide produced in the up-flow anaerobic bed and an aerobic filter for nitrification. The system successfully operated for more than 180 days with an overall organic carbon removal efficiency of 95%, in which, 82% removal was contributed by the up-flow anaerobic bed operating at a HRT of 6 h, and 13% removal by the anoxic filter. An average COD removed /sulfate removed ratio was found to be 0.76 gCOD/gSO4 or 2.28 COD/gSO4-S further confirming that the organic removal was mainly achieved by the sulfate reduction. In terms of nitrogen removal efficiency, the SANI system was found sensitive to the recirculation rate between the anoxic filter and the aerobic filter. A recirculation rate of 3Q was found to be optimal for achieving 74% of the total nitrogen removal. It was confirmed that the autotrophic denitrification was a major contributor to the total nitrogen removal in the SANI system. Sulfur balance analysis indicated that both the accumulation of elementary sulfur in the biomass and the loss of hydrogen sulfide were trivial. During the entire operation period (330 days to date), no sludge was wasted from any reactors in this system. This was further confirmed by the biomass balance simulation results that low biomass yields of sulfate reducing bacteria, autotrophic denitrifiers and nitrifiers contribute to the zero excess sludge discharge.


2020 ◽  
Vol 43 (2) ◽  
pp. 35-41
Author(s):  
Manabu KASHIWABARA ◽  
Koichiro HATA ◽  
Masaya MATSUKI ◽  
Takaoki KOGA ◽  
Toyokazu KOGA ◽  
...  

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