Combining UASB technology and constructed wetland for domestic wastewater reclamation and reuse

2003 ◽  
Vol 3 (4) ◽  
pp. 201-208 ◽  
Author(s):  
M.A. El-Khateeb ◽  
F.A. El-Gohary
Keyword(s):  
Constructed Wetland ◽  
Subsurface Flow ◽  
Typha Latifolia ◽  
Domestic Wastewater ◽  
Surface Flow ◽  
Planting Density ◽  
Uasb Reactor ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Wastewater Reclamation

The enhancement of water quality by constructed wetland systems is increasingly being employed throughout the world. For this study two treatment schemes consisting of an Up-flow Anaerobic Sludge Blanket (UASB) reactor followed by either subsurface flow (SSF) or free surface flow (FSF) constructed wetlands have been investigated. The common macrophyte in Egypt Typha latifolia (cattail) was used at a planting density of three rhizomes/m2. To evaluate the role of plants in the treatment process, an unplanted gravel bed identical to the SSF unit was operated as control. During the study period, the wetlands were fed with the UASB effluent at an organic loading rate ranging from 17.3 to 46.8 kg BOD5/ha·d (55.1 to 134.6 kgCOD/ha·d). Effectiveness of the system for the removal of key constituents (COD, BOD, TSS, nutrients and FC) has been investigated. The results showed that, the level of CODtot, and TSS in the final effluent of SSF was lower than that of FWS. Subsurface flow wetland has demonstrated higher overall efficiency than the unplanted control. FC reduction reached 4 log units. Further studies are on-going to optimize the wetland design under local environmental conditions.

Nitrite reduction and methanogenesis in a single-stage UASB reactor

2015 ◽  
Vol 72 (12) ◽  
pp. 2236-2242 ◽  
Author(s):  
L. I. Borges ◽  
C. M. López-Vazquez ◽  
H. García ◽  
J. B. van Lier
Keyword(s):  
Domestic Wastewater ◽  
High Strength ◽  
Single Stage ◽  
Nitrite Reduction ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
N Removal

In this study, nitrite reduction and methanogenesis in a single-stage upflow anaerobic sludge blanket (UASB) reactor was investigated, using high-strength synthetic domestic wastewater as substrate. To assess long-term effects and evaluate the mechanisms that allow successful nitrite reduction and methanogenesis in a single-stage UASB, sludge was exposed to relatively high nitrite loading rates (315 ± 13 mgNO2−-N/(l.d)), using a chemical oxygen demand (COD) to nitrogen ratio of 18 gCOD/gNO2−-N, and an organic loading rate of 5.4 ± 0.2 gCOD/(l.d). In parallel, the effects of sludge morphology on methanogenesis inhibition were studied by performing short-term batch activity tests at different COD/NO2−-N ratios with anaerobic sludge samples. In long-term tests, denitrification was practically complete and COD removal efficiency did not change significantly after nitrite addition. Furthermore, methane production only decreased by 13%, agreeing with the reducing equivalents requirement for complete NO2− reduction to N2. Apparently, the spatial separation of denitrification and methanogenesis zones inside the UASB reactor allowed nitrite reduction and methanogenesis to occur at the same moment. Batch tests showed that granules seem to protect methanogens from nitrite inhibition, probably due to transport limitations. Combined COD and N removal via nitrite in a single-stage UASB reactor could be a feasible technology to treat high-strength domestic wastewater.

Performance evaluation of planted and unplanted subsurface-flow constructed wetlands for the post-treatment of UASB reactor effluents

2009 ◽  
Vol 60 (12) ◽  
pp. 3025-3033 ◽  
Author(s):  
Filipe Lima Dornelas ◽  
Matheus Boechat Machado ◽  
Marcos von Sperling
Keyword(s):  
Constructed Wetlands ◽  
Subsurface Flow ◽  
Typha Latifolia ◽  
Post Treatment ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Horizontal Subsurface Flow ◽  
Subsurface Flow Constructed Wetlands ◽  
Belo Horizonte

A system comprised by a UASB (Upflow Anaerobic Sludge Blanket) reactor followed by two horizontal subsurface-flow constructed wetlands in parallel was evaluated for the treatment of the wastewater generated in the city of Belo Horizonte, Brazil (50 inhabitants each unit). One unit was planted (Typha latifolia) and the other was unplanted. Influent and effluent samples were collected for a period of seven months. The systems were able to produce final effluents with low concentrations of organic matter and suspended solids, but showed not to be efficient in the removal of nutrients. Mean effluent concentrations for the planted and unplanted units were, respectively: BOD: 15 and 19 mg/L; COD: 42 and 64 mg/L; TSS: 3 and 5 mg/L; TN: 27 and 33 mg/L; N-NH3: 25 and 29 mg/L; P Total: 1.2 and 1.5 mg/L. The planted wetland presented effluent concentrations and removal efficiencies significantly (Wilcoxon matched-pairs test, 5% significance level) better than the unplanted unit for most constituents. The study shows that horizontal subsurface-flow constructed wetlands can be effectively used as a post-treatment option for the effluent from UASB reactors.

scholarly journals Performance of horizontal flow constructed wetland for secondary treatment of domestic wastewater in a remote tribal area of Central India

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Reetika Shukla ◽  
Deepak Gupta ◽  
Gurudatta Singh ◽  
Virendra Kumar Mishra
Keyword(s):  
Constructed Wetland ◽  
Typha Latifolia ◽  
Oxygen Demand ◽  
Central India ◽  
Domestic Wastewater ◽  
Quality Parameters ◽  
Surface Flow ◽  
Fecal Coliforms ◽  
Commelina Benghalensis ◽  
Treated Effluent

AbstractThe purification of the primary treated domestic sewage was performed in the present study through the horizontal sub-surface flow constructed wetland (CW) of 10 × 3.5 m dimension. The study was performed using three setups of CW 1 (Unplanted CW), CW 2 (CW planted with macrophyte Typha latifolia), and CW 3 (CW planted with two species of macrophyte T. latifolia and Commelina benghalensis). The purification experiments were performed by converting one type of CW into the other form sequentially, i.e., CW 1 was built first and after the experiments, it was converted into CW 2 and then CW 3. The CW was filled with a layer of coarse and fine gravel of 70 cm depth as filter media in 1:2 ratio. Each set of wetland was operated for 3 months (12 wk) during which the treatment performance of wetlands for basic physicochemical parameters was evaluated. The CW was operated in continuous mode at an average hydraulic loading rate of 250 L h− 1 and the treated effluent was analysed twice every week at four different sampling points having hydraulic retention times (HRT) of 12, 24, 36 and 48 h for important sewage quality parameters All the three setups of CW were able to clean the primary treated sewage significantly. Among the three sets of wetlands used, CW 3 was the best performer removing 79, 77, 79, 79, and 78% of biochemical oxygen demand, chemical oxygen demand, nitrate, ammonia, and phosphate respectively in 48 h HRT. Among the three sets of wetlands, the CW 3 removed the highest percent of total coliforms, fecal coliforms, and E. coli as 64, 61 and 52% respectively.

Nitrogen dynamics in a constructed wetland system treating landfill leachate

2007 ◽  
Vol 56 (3) ◽  
pp. 151-158 ◽  
Author(s):  
C.B. Kinsley ◽  
A.M. Crolla ◽  
N. Kuyucak ◽  
M. Zimmer ◽  
A. Laflèche
Keyword(s):  
Constructed Wetland ◽  
Plug Flow ◽  
Domestic Wastewater ◽  
Pilot Scale ◽  
Surface Flow ◽  
Treatment System ◽  
Organic Loading Rate ◽  
Sand Filters ◽  
Ammonium Removal ◽  
Hydraulic Loading

A pilot scale treatment system was established in 2002 at the Laflèche Landfill in Eastern Ontario, Canada. The system consists of a series of treatment steps: a stabilisation basin (10,000 m3), a woodland peat trickling filter (5,200 m2), a subsurface flow constructed wetland planted in Phragmites sp. (2,600 m2), a surface flow constructed wetland planted in Typha sp. (3,600 m2) and a polishing pond (3,600 m2). The system operates from May to December with leachate being recycled within the landfill during the winter months. Hydraulic loading was increased three-fold over four operating seasons with nitrogen and organic mass loading increasing six-fold. Excellent removal efficiencies were observed with 93% BOD5, 90% TKN and 97% NH4-N removed under the highest loading conditions. Almost complete denitrification was observed throughout the treatment system with NO3-N concentrations never exceeding 5 mg·L−1. The peat filter reached treatment capacity at a hydraulic loading of 4 cm·d−1 and organic loading rate of 42 kg BOD·ha−1·d−1, which is consistent with design criteria for vertical flow wetland systems and intermittent sand filters. The first order plug flow kinetic model was effective at describing TKN and ammonium removal in the SSF and FWS wetlands when background concentrations were taken into account. Ammonium removal k-values were consistent with the literature at 52.6 and 57.7 yr−1 for the SSF and FWS wetlands, respectively, while TKN k-values at 6.9 and 7.7 yr−1 were almost an order of magnitude lower than literature values, suggesting that leachate TKN could contain refractory organics not found in domestic wastewater.

Evaluation of clogging in planted and unplanted horizontal subsurface flow constructed wetlands: solids accumulation and hydraulic conductivity reduction

2013 ◽  
Vol 67 (6) ◽  
pp. 1345-1352 ◽  
Author(s):  
André Cordeiro De Paoli ◽  
Marcos von Sperling
Keyword(s):  
Hydraulic Conductivity ◽  
Constructed Wetlands ◽  
Subsurface Flow ◽  
Typha Latifolia ◽  
Surface Flow ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Operational Problem ◽  
Horizontal Subsurface Flow ◽  
Comparative Results

This study aimed to evaluate the behaviour of two horizontal subsurface flow constructed wetland units regarding solids build up and clogging of the filter medium. In order to analyse the causes of this process, which is considered the major operational problem of constructed wetlands, studies were carried out to characterize accumulated solids and hydraulic conductivity at specific points of the beds of two wetlands (planted with Typha latifolia and unplanted units) receiving effluent from an upflow anaerobic sludge blanket reactor treating sanitary sewage (population equivalent of 50 inhabitants each unit). The experiments were performed after the units were operating for 2 years and 4 months. This study presents comparative results related to the quantification and characterization of accumulated solids and hydraulic conductivity along the length and width of the filter beds. Approximately 80% of the solids found were inorganic (fixed). Near the inlet end, the rate interstitial solids/attached solids was 5.0, while in the outlet end it was reduced to 1.5. Hydraulic conductivity was lower near the inlet of the units (as expected) and, by comparing the planted wetland with the unplanted, the hydraulic conductivity was lower in the former, resulting in larger undesired surface flow.

scholarly journals Performance of Filterbeds and Macrophytes in Vertical Constructed Wetland for Treating Domestic Sewage Effluent

2021 ◽  
Author(s):  
Vanitha Thammaiah ◽  
Manjunatha Hebbara ◽  
Manjunatha Mudukapla Virupakshappa
Keyword(s):  
Constructed Wetland ◽  
Suspended Solids ◽  
Typha Latifolia ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Organic N ◽  
Sewage Effluent ◽  
Ammoniacal Nitrogen ◽  
Wetland Treatment ◽  
Nitrogen Phosphorus

Abstract An experiment with different filterbeds and macrophytes was carried-out to study their phytoremediation capacity on the efficiency of domestic wastewater treatment through constructed wetland (CW) during November to March, 2017-18 at University of Agricultural Sciences, Dharwad campus, Karnataka, India. Twenty treatment combinations involving five types of filterbeds (FB-1: gravel, FB-2: gravel-sand-gravel, FB-3: gavel-sand-brick-gravel, FB-4: gravel-sand-charcoal-gravel and FB-5: gravel-sand-(charcoal+brick)-gravel) and four macrophytes (MP-1: Typha latifolia, MP-2: Brachiaria mutica, MP-3: Canna indica and MP-4: Phragmites sps.) were evaluated for treating domestic wastewater. After 120 days from start, across treatment combinations, water electrical conductivity (EC), total dissolved and suspended solids (TDS-TSS), biological oxygen demand (BOD), chemical oxygen demand (COD), sodium, sodium adsorption ratio (SAR), residual sodium carbonate (RSC), bicarbonates, total nitrogen-phosphorus-potassium (N-P-K) and boron (B) were reduced by more than 40 per cent due to wetland treatment. The system enhanced the mineralization of organic nitrogen to ammoniacal nitrogen (NH4+-N) and nitrate nitrogen (NO3-N) fractions. Among filterbeds, Type-5 caused higher reduction in pH, EC, BOD, COD and Organic-N while, Type-4 proved efficient in removing total solids and lowering pH in the sewage effluent. The Type-3 filterbed removed more suspended solids, potassium and ammoniacal nitrogen. Among the macrophytes, Brachiaria (paragrass) removed more nitrogen and potassium while, Phragmites removed more nitrogen, phosphorus and boron. The flexibility of implementation allows the CW to be adapted to different sites with different configurations, being suitable as main, secondary or tertiary treatment stage.

scholarly journals The Concept of Wastes to Energy Using Sugary Wastes

2012 ◽  
Vol 9 ◽  
pp. 57-62
Author(s):  
Fiza Sarwar ◽  
Wajeeha Malik ◽  
Muhammad Salman Ahmed ◽  
Harja Shahid
Keyword(s):  
Volatile Fatty Acids ◽  
Loading Rate ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Uasb Reactor ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Loading Rates ◽  
Sugar Mills ◽  
Anaerobic Sludge Blanket

Abstract: This study was designed using actual effluent from the sugary mills in an Up-flow Anaerobic Sludge Blanket (UASB) Reactor to evaluate treatability performance. The reactor was started-up in step-wise loading rates beginning from 0.05kg carbon oxygen demand (COD)/m3-day to 3.50kg-COD/m3-day. The hydraulic retention time (HRT) was slowly decreased from 96 hrs to eight hrs. It was observed that the removal efficiency of COD of more than 73% can be easily achieved at an HRT of more than 16 hours corresponding to an average organic loading rate (OLR) of 3.0kg-COD/m3-day, at neutral pH and constant temperature of 29°C. The average VFAs (volatile fatty acids) and biogas production was observed as 560mg/L and 1.6L/g-CODrem-d, respectively. The average methane composition was estimated as 62%. The results of this study suggest that the treatment of sugar mills effluent with the anaerobic technology seems to be more reliable, effective and economical.DOI: http://dx.doi.org/10.3126/hn.v9i0.7075 Hydro Nepal Vol.9 July 2011 57-62

Open trickling filter: an innovative, cheap and simple form of post-treatment of sanitary effluents from anaerobic reactors in small communities

2012 ◽  
Vol 2 (2) ◽  
pp. 59-67 ◽  
Author(s):  
P. C. Vieira ◽  
M. von Sperling
Keyword(s):  
Loading Rate ◽  
Oxygen Demand ◽  
Post Treatment ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Trickling Filter ◽  
Small Communities ◽  
Capital Costs

We aimed to evaluate the performance and cost savings of an innovative design of a trickling filter (TF) for small population sizes, developed at the Federal University of Minas Gerais, Brazil referred to as an open trickling filter (OTF). The OTF had no side walls and no perforated bottom slab, and was applied for the post-treatment of sanitary sewage from an upflow anaerobic sludge blanket (UASB) reactor. The OTF had crushed-stone packing (3.5 m high) and was operated with an average surface hydraulic loading rate of 4.1 m3 m−2 d−1 and an average volumetric organic loading rate of 0.10 kg BOD m−3 d−1 (biochemical oxygen demand). The average concentrations obtained at the OTF effluent were 48 mg TSS L−1 (total suspended solids), 132 mg COD L−1 (chemical oxygen demand), 51 mg BOD L−1, 19 mg TKN L−1 (total Kjeldahl nitrogen), 16 mg NH4+-N L−1 and 10 mg NO3−-N L−1, complying with local discharge standards. Analysis of the construction costs indicated savings of 74% compared to conventional TF. Based on the performance, compactness, simplicity and reduced capital costs, it is believed that the proposed OTF is a good alternative for small communities, especially in developing countries.

Toxicity and treatability of leachate: application of UASB reactor for leachate treatment from Okhla landfill, New Delhi

2012 ◽  
Vol 65 (10) ◽  
pp. 1887-1894 ◽  
Author(s):  
V. Singh ◽  
A. K. Mittal
Keyword(s):  
Oxygen Demand ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
New Delhi ◽  
Leachate Treatment ◽  
Feed Composition ◽  
Laboratory Scale Reactor ◽  
Anaerobic Sludge Blanket

This study reports applicability of upflow anaerobic sludge blanket (UASB) process to treat the leachate from a municipal landfill located in Delhi. A laboratory scale reactor was operated at an organic loading rate of 3.00 kg chemical oxygen demand (COD)/m3 d corresponding to a hydraulic retention time (HRT) of 12 h for over 8 months. The effect of toxicity of leachate, and feed composition on the treatability of leachate was evaluated. Average COD of the leachate, during the study period varied between 8,880 and 66,420 mg/l. Toxicity of the leachate used during a period of 8 months varied from LC50 1.22 to 12.35 for 96 h. The removal efficiency of soluble COD ranged between 91 and 67% for fresh leachate and decreased drastically from 90 to 35% for old leachate having high toxicity. The efficiency varied from 81 to 65%. The reactor performed more efficiently for the treatment of fresh leachate (less toxic, LC50 11.64, 12.35, and 12.15 for 96 h) as compared with old leachate (more toxic, LC50 1.22 for 96 h). Toxicity of the leachate affected its treatment potential by the UASB.

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