scholarly journals Natural Treatment of High-Strength Reverse Osmosis Concentrate by Constructed Wetlands for Reclaimed Water Use

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 158 ◽  
Author(s):  
Rajat K. Chakraborti ◽  
James S. Bays
Keyword(s):  
Pilot Study ◽  
Reverse Osmosis ◽  
Constructed Wetlands ◽  
Carbon Assimilation ◽  
Ammonia Nitrogen ◽  
Treated Wastewater ◽  
Evaporative Water ◽  
Mass Removal ◽  
Treated Effluent ◽  
Natural Treatment

A pilot study using natural treatment methods such as a horizontal subsurface flow in constructed wetlands to treat the reverse osmosis concentrate (ROC) was conducted to manage nutrient and metals to reclaim the product water for the coastal wetlands and agriculture use. ROC had a significantly greater concentration of constituents than concentrations typically found in effluent of secondary treated wastewater. During the six-month wetland pilot study, the removal of nutrients from the ROC was monitored. Bulrush (Schoenoplectus californicus), a common wetland plant, tolerated high total dissolved solids (11,000–12,700 mg/L) and provided significant mass removal of nutrients in the concentrate (61% removal of nitrogen and 21% removal of phosphorus) under two hydraulic residence times (HRT1 = 2.5 days and HRT2 = 5 days). Concentration-based reductions of oxidized nitrogen, ammonia-nitrogen, orthophosphate were 63%, 23%, and 23% during HRT1 and 55%, 24%, and 11% during HRT2, respectively. Nutrient mass balance estimates of this microbially dominated wetland system and analysis of mass transformation pathways were also performed. Because of evaporative water loss, mass removal efficiencies were significant. Key processes included denitrification for nitrogen removal, possibly supplemented with Annamox reduction of NO3-N; labile carbon assimilation supporting oxidized nitrogen reduction; and phosphate-P uptake and precipitation within the gravel substrate. The results indicated that engineered wetland treatment offers useful benefits to the management of ROC produced from secondary treated effluent of wastewater through reduction in volume through evapotranspiration and reduction in concentration through biological transformations for beneficial reuse.

scholarly journals Application of constructed wetlands using Vetiveria zizanioides and Phragmites australis in the landfill leachate treatment

2019 ◽  
Vol 2 (5) ◽  
pp. 177-183
Author(s):  
Le Ai Nguyen ◽  
Trinh Thi Mong Le
Keyword(s):  
Constructed Wetlands ◽  
Landfill Leachate ◽  
Industrial Wastewater ◽  
Ammonia Nitrogen ◽  
Vetiveria Zizanioides ◽  
Leachate Treatment ◽  
Effluent Quality ◽  
Treated Effluent ◽  
Wastewater Quality ◽  
Wetland System

Constructed wetlands have been widely applied for removing pollutants in the leachate recently. In this study, constructed wetland system combined vertical flow and horizontal flow, using Vetiveria zizanioides L. and Phragmites australis, was set in a laboratory scale to assess the leachate treatment ability. The landfill leachate was added to the system with increasing concentration to evaluate the treatment ability by the time. The results showed that the removal efficiency reached the highest when the COD concentration was 575 mg/L, including BOD5 (96.48%), COD (83.24%), total nitrogen (91.43%), total phosphorus (77.84%), ammonia nitrogen (86.47%), and color (87.91%). Furthermore, the treated effluent quality reached the class A of the Vietnamese standard on industrial wastewater quality. Beside, when physicochemically treated leachate (coagulation – flocculation) (COD concentration was 1255.50 mg/L), was added to the system, the removing efficiencies remained stable by the time, with the efficiency of ammonia nitrogen removing (93.48%), BOD5 (94.86%), total phosphorus (96.67%), total nitrogen (95.81%). Besides, the treated effluent quality reached the class B of the Vienamese standard on industrial wastewater quality. On other hand, COD and color removing efficiencies were also high at the first stage and tended to reduce rapidly by the time. Therefore, the EM called Bayer Pond Plus added to the system could increase and substained the removing efficiencies of COD (66.61%), color (81.40%). The results of this study showed that constructed wetland system had potential in the landfill leachate treatment.

scholarly journals Enabling Water Reuse by Treatment of Reverse Osmosis Concentrate: The Promise of Constructed Wetlands

2021 ◽  
Author(s):  
Rachel C. Scholes ◽  
Angela N. Stiegler ◽  
Cayla M. Anderson ◽  
David L. Sedlak
Keyword(s):  
Reverse Osmosis ◽  
Constructed Wetlands ◽  
Water Reuse

Experiences with a top layer of gravel to enhance the performance of vertical flow constructed wetlands at cold temperatures

2009 ◽  
Vol 59 (6) ◽  
pp. 1111-1116 ◽  
Author(s):  
Guenter Langergraber ◽  
Alexander Pressl ◽  
Klaus Leroch ◽  
Roland Rohrhofer ◽  
Raimund Haberl
Keyword(s):  
Organic Matter ◽  
Constructed Wetlands ◽  
Common Reed ◽  
Treated Wastewater ◽  
Second Phase ◽  
Vertical Flow ◽  
Cold Temperatures ◽  
Main Layer ◽  
Gravel Layer ◽  
Filter Bed

In a first phase of this study it was shown that the Austrian effluent standards for organic matter could not be met in winter for vertical flow (VF) beds designed for and loaded with 27 g COD.m−2.d−1 (3 m2 per person equivalent). The aim of this second phase of the study was to investigate, if the performance of a constructed wetland can be enhanced, i.e. if the effluent requirements can be met, when an additional gravel layer (15 cm, 4–8 mm) is added on top of the main layer of the VF bed. The hypothesis was that this top layer would increase the thermal insulation and consequently the temperatures in the filter bed during cold periods, thus resulting in higher removal efficiencies during winter. Two VF beds were operated in parallel; one bed with such a 15 cm top layer, one without. Otherwise the construction of both beds was identical: surface area of about 20 m2, 50 cm main layer (grain size 0.06–4 mm, d10=0.2 mm; d60=0.8 mm), planted with common reed (Phragmites australis). The beds were intermittently loaded 4 times per day with mechanically pre-treated wastewater (hydraulic loading: 47 mm.d−1; median value of the influent concentration: 505 mg COD.L−1). Despite a better performance during the first winter, the bed with additional top layer showed in general a very unstable performance. It is assumed that the main reason for this was that the oxygen transfer was reduced by the additional top layer so far that suspended organic matter could not any longer be degraded in between loadings. Therefore clogging of the filter occurred.

scholarly journals Application of forward osmosis in reusing the brackish concentrate produced in reverse osmosis plants with secondary treated wastewater as feed solution: a case study

2016 ◽  
Vol 6 (4) ◽  
pp. 533-543 ◽  
Author(s):  
W. D. Wang ◽  
M. Esparra ◽  
H. Liu ◽  
Y. F. Xie
Keyword(s):  
Reverse Osmosis ◽  
Membrane Fouling ◽  
Water Flux ◽  
Forward Osmosis ◽  
Pump Energy ◽  
Feed Solution ◽  
Disinfection Byproducts ◽  
Treated Wastewater ◽  
Membrane Flux ◽  
Flux Decline

This study evaluated the feasibility of forward osmosis (FO) in diluting and reusing the concentrate produced in a reverse osmosis (RO) plant in James City County, VA. Secondary treated wastewater (STW) was used as the feed solution. Findings indicated that pH had slight effects on the water flux of the FO membrane. As the concentration of total dissolved solids (TDS) in the concentrate was diluted from 12.5 to 1.0 g/L or the temperature in the STW decreased from 23 to 10 °C, the membrane flux decreased from 2.2 to 0.59 and 0.81 L/(m2 h), respectively. The FO membrane showed a good performance in the rejection of organic pollutants, with only a small part of the protein-like substances and disinfection byproducts permeating to the diluted concentrate. During an 89-hour continuous operation, water flux decline due to membrane fouling was not observed. Controlling the TDS in the second-stage FO effluent at 1.5 g/L, approximately 8.3% of the pump energy input could be saved. The consumption of groundwater was reduced from 22.7 × 103 to 10.6 × 103 m3/d. FO was proved to be an effective method in both diluting the discharged concentrate and reducing the energy consumption of RO.

Combined organic carbon and complete nitrogen removal using anaerobic and aerobic upflow filters

1994 ◽  
Vol 30 (12) ◽  
pp. 297-306 ◽  
Author(s):  
Joseph Akunna ◽  
Claude Bizeau ◽  
René Moletta ◽  
Nicolas Bernet ◽  
Alain Héduit
Keyword(s):  
Organic Carbon ◽  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Nitrogen Loss ◽  
Ammonia Nitrogen ◽  
Cod Removal ◽  
Cod Removal Efficiency ◽  
Treated Effluent ◽  
Treated Effluents ◽  
Aerobic And Anaerobic

Two laboratory upflow aerobic and anaerobic filters fed with synthetic wastewaters were used to study firstly the effects of aeration rate on the nitrification of anaerobically pre-treated effluents and secondly the effects of recycle-to-influent ratios on methane production rate, denitrification and nitrification performances of a combined aerobic and anaerobic wastewater treatment process. Nitrification of anaerobically pre-treated effluent was accompanied by aerobic post-treatment for residual COD removal. A comparison of nitrification performances using autotrophic medium and anaerobically pre-treated effluents (containing 1203 mg COD 1−1) with the same ammonia nitrogen concentration of about 300 mg NH4-N 1−1 showed that 3% of added ammonia nitrogen was assimilated by autotrophic nitrifiers during nitrification of the autotrophic medium while up to 30% was assimilated by both nitrifiers and heterotrophs during organic carbon removal and nitrification of anaerobically pre-treated effluent. Furthermore, it was suspected that significant nitrogen loss through denitrification occured in the aerobic filter especially at low aeration rates. In the study of the combined aerobic-anaerobic system, maximum ammonia nitrogen removal of 70% through denitrification was obtained at recycle-to-influent ratios of 4 and 5. COD removal efficiency in the anaerobic filter decreased from 77 to 60% for recycle-to-influent ratios of zero to 5. Overall COD removal efficiency of the entire system was constant at about 99% due to heterotrophic COD removal in the aerobic filter.

scholarly journals Impact of Partially Treated Wastewater on Downstream Water Quality of Notwane River in Botswana

2018 ◽  
pp. 1-9
Author(s):  
Gilbert K. Gaboutloeloe ◽  
Gugu Molokwe ◽  
Benedict Kayombo
Keyword(s):  
Water Quality ◽  
Pearson Correlation ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Treated Wastewater ◽  
Nitrate N ◽  
River Stretch ◽  
Ph Range ◽  
The Impact

The impact of partially treated wastewater on the water quality of Notwane river stretch in the Gaborone region of Botswana was investigated. Water samples collected at effluent discharge point and three other sampling sites downstream were analyzed for pH, temperature, Biological Oxygen Demand (BOD5), Ammonia-nitrogen (Ammonia-N) and Nitrate-nitrogen (Nitrate-N). Sampling was conducted bi-weekly between February 2013 and April 2013. The ranges of measured parameters were:  pH (7.6-8.5), temperature (22-23ºC), BOD5 (11.2-27.0 mg/l), Ammonia-N (2.4-60.5 mg/l), Nitrate-N (20.6-28.6 mg/l). Analysis of variance, Games-Howel multiple comparisons and Pearson correlation were used to separate variable means. The results signal river non-point pollution due to runoff inflow of organics mainly from land use and domestic waste dumping by nearby dwellings. Temperature, BOD5, and pH range values were all within the Botswana Bureau of Standards (BOBS) limit while the maximum Ammonia-N and Nitrate-N were above BOBS limit by 50.5 mg/l and 6.6 mg/l, respectively. Regulations on indiscriminate waste dumping and discharge standards adherence should be enforced.

Efficiency of RO/NF membranes at the removal of veterinary antibiotics

2012 ◽  
Vol 65 (2) ◽  
pp. 317-323 ◽  
Author(s):  
D. Dolar ◽  
A. Vuković ◽  
D. Ašperger ◽  
K. Košutić
Keyword(s):  
Sewage Sludge ◽  
Synergistic Effect ◽  
Reverse Osmosis ◽  
Treated Wastewater ◽  
Antibiotic Residues ◽  
Veterinary Antibiotics ◽  
Aquaculture Feed ◽  
Municipal Biosolids ◽  
Land Disposal ◽  
High Level

The production of pharmaceuticals has increased rapidly during the last several decades as they have been used for the health of both humans and animals. Routes of environmental exposure include the release of treated wastewater, the land disposal of livestock manures and municipal biosolids (i.e. sewage sludge), as well as the use of medicated aquaculture feed. This study deals with application of reverse osmosis (RO) and nanofiltration (NF) membranes for removing of antibiotic residues (sulfamethoxazole, trimethoprim, ciprofloxacin, dexamethasone and febantel) and their mixture. According to the results obtained in this work the use of RO (LFC–1 and XLE) and the tight NF (NF90) membranes are recommended to achieve a high level of retention (>95%) of all selected veterinary antibiotics (VAs). Nanofiltration NF270, NF and HL membranes showed a lower rejection of individual components, but much higher in a mixture solution, due to the synergistic effect.

Research on Treatment of Domestic Sewage with Aerobic Denitrifying Bacteria Immobilized by Carbon Fiber

2014 ◽  
Vol 675-677 ◽  
pp. 627-632 ◽  
Author(s):  
Qun Wei ◽  
Di Lv ◽  
Mei Hui Huang ◽  
De Shui Yu ◽  
Jian Qiang You
Keyword(s):  
Nitric Acid ◽  
Carbon Fiber ◽  
Removal Rate ◽  
Denitrifying Bacteria ◽  
Ammonia Nitrogen ◽  
Domestic Sewage ◽  
Treated Wastewater ◽  
Adsorption Method ◽  
Concentrated Sulfuric Acid ◽  
Cod Removal Rate

Aerobic denitrifying bacteria, a fast and efficient strain, is extensively adopted in the wastewater sphere, and immobilized aerobic denitrifying bacteria denitrification Technology, to some extent, solves many problems existing in the direct application of aerobic denitrifying bacteria. Concentrated sulfuric acid, nitric acid, potassium permanganate, ferric chloride etc. are used to pretreat carbon fiber respectively, and then the modified the carbon fiber is applied to fix the activated aerobic denitrifying bacteria to investigate the effects of the modification of the carbon fiber and the effects of wastewater treatment with immobilized aerobic denitrifying bacteria. The results showed that the fixed efficiency of the strain with carbon fiber pretreated by nitric acid reached 50% and when the strain fixed by the modified carbon fiber in adsorption method treated wastewater, the ammonia nitrogen removal rate reached 78% and the COD removal rate was always stabilized above 40% in three days.

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