Wastewater Treatment by Artificial Wetlands

1985 ◽  
Vol 17 (4-5) ◽  
pp. 443-450 ◽  
Author(s):  
R. M. Gersberg ◽  
B. V. Elkins ◽  
C. R. Goldman

This report describes studies of artificial wetlands at Santee, California which demonstrate the capacity of these systems for integrated secondary treatment (BOD and suspended solids removal) and advanced treatment (nitrogen removal) of municipal wastewater effluents. When receiving a blend of primary (1°) and secondary (2°) wastewaters at a blend ratio of 1:2 (6 cm per day 1° : 12 cm per day 2° ), mean removal efficiencies for a complete year of operation from July, 1982 through July, 1983 were 80% for total nitrogen (TN) and 80% for total inorganic nitrogen, with the mean inflow TN level of 21.5 mgl−1 reduced to a mean value of 4.3 mgl−1 in the wetland effluent. The BOD and suspended solids removal efficiencies were 93% and 88% respectively. The mean wetland effluent values for both BOD and suspended solids were below the 10/10 mgl−1 standard for advanced secondary treatment. When primary effluent was the sole source of inflow to the artificial wetlands, BOD and suspended solids levels approaching the quality of a secondary treated effluent (30/30 mgl−1) could be attained at an application rate of 6-8.3 cm per day. In this case, mean BOD and suspended solids removal efficiencies for the complete year from July, 1982 through August, 1983, were 78% and 80% respectively, with the effluent levels reduced to mean values of 33 mgl−1 for BOD and 10 mgl−1 for suspended solids. At the application rate of 6 cm per day, our study shows that only 16 acres (6.5 ha) of constructed wetlands would be required to treat 3785 m3 of primary wastewaters to secondary treatment levels. Data on capital and O&M cost show that artificial wetlands are competitive with other treatment technologies available to small to medium sized communities.

2012 ◽  
Vol 65 (6) ◽  
pp. 1109-1115 ◽  
Author(s):  
L. Rodríguez-Hernández ◽  
A. L. Esteban-García ◽  
A. Lobo ◽  
J. Temprano ◽  
C. Álvaro ◽  
...  

A new hybrid membrane bioreactor (HMBR) has been developed to obtain a compact module, with a small footprint and low requirement for aeration. The aim of this research was to assess its performance. The system consists of a single vertical reactor with a filtration membrane unit and, above this, a sponge fixed bed as support medium. The aeration system is located under the membrane unit, allowing for membrane cleaning, oxygenation, biofilm thickness control and bulk liquid mixing. Operated under continuous aeration, a bench-scale reactor (70 L) was fed with pre-treated, raw (unsettled) municipal wastewater. BOD5 and suspended solids removal efficiencies (96 and 99% respectively) were comparable to those obtained with other membrane bioreactors (MBRs). Total nitrogen removal efficiencies of 80% were achieved, which is better than those obtained in other HMBRs and similar to the values reached using more complex MBRs with extra anoxic tanks, intermittent aeration or internal deflectors.


2009 ◽  
Vol 59 (4) ◽  
pp. 723-728 ◽  
Author(s):  
P. Castilla ◽  
L. Aguilar ◽  
M. Escamilla ◽  
B. Silva ◽  
Z. Milán ◽  
...  

Municipal wastewater was amended with organic garbage leachates at a concentration around 700 mgCODsoluble/L and fed to three different anaerobic systems to compare their performance: a down flow fluidized bed (DFFB), an expanded granular sludge bed (EGSB) and a zeolite-packed anaerobic filter reactor (ZPF). The DFFB and EGSB reactors were operated at HRT of 6 and 4 h and the ZPF reactor at 12 and 36 h. Organic loads rate for the DFFB reactor were 2.3±0.9 and 4.8±1.8 gCOD/L·d, with removal efficiencies around 40% and a methane productivity of 0.2±0.03 L/Lreactor·d. For the EGSB reactor, organic loads tested were 2.1±0.9 and 4.3±1.3 gCOD/L·d, removal efficiencies attained were of 77.6±12.7% and 84.4±4.9%, respectively at both conditions and total suspended solids were removed in 54.6±19.3%, while methane productivity at 4 h HRT was of 1.29±0.4 L/Lreactor·d. The ZPF reactor was operated at lower organic loading rates, 1.4±0.27 and 0.42±0.13 gCOD/L·d and attained removal efficiencies of 48±18% and 83±8%, respectively, reaching a methane productivity of 0.21±0.09 and 0.12±0.04 L/Lreactor·d, 83±8.0% of total suspended solids were retained in the reactor and as HRT was increased ammonium concentrations increased in 39%. Specific methanogenic activity in all systems was around 0.2 gCOD-CH4/gVSS d.


1991 ◽  
Vol 24 (7) ◽  
pp. 285-292 ◽  
Author(s):  
F. A. El-Gohary ◽  
S. I. Abo-Elela ◽  
S. A. Shehata ◽  
H. M. El-Kamah

Physico-chemical sewage treatment via coagulation-sedimentation is put in action for suspended solids removal. The effectiveness of this technology concerning the soluble organic content is extremely low. In direct comparison, the use of a biological sand-bed and a high-rate oxidation pond as a tertiary treatment for the chemically treated effluent brought about a substantial increase in efficiency. Experimental investigations performed led to the conclusions that, for the reuse of wastewater for irrigation, chemical treatment is appropriate. For discharge of treated effluents into surface water, combination of the physico-chemical-biological scheme is recommended.


2015 ◽  
Vol 10 (2) ◽  
pp. 319-327 ◽  
Author(s):  
A. Franchi ◽  
D. Santoro

Rotating belt filtration (RBF) is a technology designed for the removal of suspended solids, and effluent organic matter from wastewater that has been recently undergoing intensive development and testing. Generally, RBF can remove solids to meet Ten State Standards (‘Primary settling of normal domestic wastewater can be expected to remove approximately one-third of the influent BOD5 when operating at an overflow rate of 41 m3/(m2 d) [1,000 gallons per day/square foot]’) and European council directive standards (at least 50% total suspended solids (TSS) and 20% Biological Oxygen Demand (BOD) removal). Recent testing have also shown that, when a polymer is added upstream of the RBF, solids and organics removal is significantly enhanced. Advantages of RBF include reduced space requirement, ability to support small mesh without clogging, reduced civil engineering site work, and modular construction allowing for reduced design work, faster installation, and ease of plant expansion. Additional site-specific advantages may include reduced capital and operation costs, and energy savings (e.g. reduced aeration costs following the addition of primary solids removal by RBF against the baseline case where primary solids removal is not practiced). As a matter of fact, when RBF is operated as a pretreatment to remove 50% of the incoming TSS prior to the biological aerated tank, a significant decrease in power consumption ranging from 22 to 28% can be expected if compared to the case where no primary treatment is used. This paper focuses on the current status of development of the technology and provides a literature review of recent experimental studies focused on testing RBF.


1992 ◽  
Vol 27 (3) ◽  
pp. 575-600 ◽  
Author(s):  
J. Fein ◽  
M. Beavan ◽  
A. Effio ◽  
N. Gray ◽  
N. Moubayed ◽  
...  

Abstract A comprehensive study (physical, chemical and biological parameters) was made of a conventional secondary treatment system (aeration stabilization basin) linked to a state-of-the-art bleached kraft mill. Overall the system removed 88% of the BOD, 62% of the COD, 47% of the TOC, 56% of the AOX and 69% of the suspended solids present in the influent stream. Of the total removed, the first aeration cell was the most active area of the system, responsible for the removal of 70% of the BOD5, 57% of the COD, 43% of the TOC, 75% of the AOX, and all of the acute toxicity entering the system. Cell 2 was found to be carbon limited. Unlike Cell 1, Cell 2 played a significant role in suspended solids removal.


2018 ◽  
Vol 2017 (1) ◽  
pp. 48-57
Author(s):  
Tayla Gabriela da Luz ◽  
Valber Sales ◽  
Raquel Dalla Costa da Rocha

Abstract Biopolymers have the ability to form gels that can be used in coagulation/flocculation processes. For this reason, the present work evaluated the application of the Aloe arborescens gel as a biopolymer in the treatment of the effluent generated in galvanic processes. The centesimal, thermogravimetric and texture profiles, as well as the functional groups and the biopolymer's performance in the treatment was analyzed. The performance results were evaluated by central composite rotational design 23. The variables biopolymer concentration, aluminum sulphate and initial pH of the effluent were significant at the confidence level of 95%. The Cr(VI) removal efficiency ranged from 6.37% to 37.74%; significant reductions in dissolved solids (89.80% to 94.13%) and suspended solids (71.06% to 90.00%) were also observed. The treated effluent still presents parameters above the regulatory limits stated by the legislation, therefore, the biopolymer could be used as initial treatment for solids removal.


2001 ◽  
Vol 44 (1) ◽  
pp. 113-120 ◽  
Author(s):  
G. Esposito ◽  
C. Bastianutti ◽  
G. Bortone ◽  
F. Pirozzi ◽  
S. Sgroi

The effects of suppressing primary sedimentation on nitrogen removal efficiency of a pre-denitrification system have been evaluated for a large municipal wastewater treatment plant. Simulations have been carried out using the STOAT model. For both the process schemes with and without primary sedimentation, nitrification efficiencies are calculated for increasing influent loads of COD, total N and suspended solids. The sensitivity analysis shows that for the usual carbon to nitrogen ratios in the raw influent both the process schemes allow the requested removal efficiencies, whereas for significantly high C/N ratios the scheme with primary sedimentation is preferable.


2020 ◽  
Vol 55 (4) ◽  
pp. 382-393
Author(s):  
Guillaume LeBlond ◽  
Patrick M. D'Aoust ◽  
Chris Kinsley ◽  
Robert Delatolla

Abstract The microsieving discfilter technology was investigated at the pilot scale. The pilot was configured to treat the effluent from a municipal wastewater multi-lagoon facility consisting of two facultative lagoons and a third seasonally aerated lagoon that is aerated to mitigate hydrogen sulfide release. The 10 μm filter, operated without chemical enhancement, demonstrates 60.1 ± 22.6% removal of the lagoon effluent total suspended solids (TSS) during periods of operation without aeration of the third lagoon. Aeration of the third lagoon of the multi-lagoon system prior to discharge renders the 10 μm filter cloth ineffective with respect to solids removal. The 5 μm filter cloth performs effective nonchemically enhanced removal of solids even during aeration of the lagoon, removing 68.2 ± 9.85% of effluent TSS. The greater performance of the 5 μm filter was achieved at the expense of a lower maximum conveyance capacity than the 10 μm filter. The 10 and 5 μm filters decrease the effluent total phosphorus (TP) concentrations by 0.14 and 0.13 mg-P/L, respectively. Algae, characterized as Chlorophyll α, shows removal from influent concentrations of 10.25 ± 4.19 μg/L to concentrations of 4.61 ± 1.28 μg/L for the 10 μm filter, and 4.10 ± 0.65 μg/L for the 5 μm filter.


1989 ◽  
Vol 21 (1) ◽  
pp. 93-99 ◽  
Author(s):  
Fatma A. El-Gohary ◽  
Sohair I. Abo-Elela ◽  
H. M. El-Kamah

The feasibility of applying direct advanced treatment to municipal wastewater has been investigated. A. two-stage scheme was implemented. The first stage was direct chemical coagulation of primary effluent using different coagulants to remove suspended solids and reduce the carbon to nitrogen ratio to a range suitable for nitrification. The second stage was biological sand-bed to oxidize ammonia to nitrate. The pilot plant was designed to treat 6m3/day. The results obtained showed that chemical coagulation using ferric chloride gave high quality effluent suitable for agricultural purposes. Nitrification of the 2 chemically treated effluent using sand-bed at an overflow rate of 1.358 m3/m2/d completely eliminated ammonia. Almost complete removal of suspended solids was achieved. Residual COD and BOD values were 45 mg/l and 15,5 mg/l, respectively. Fish biotoxicity was completely eliminated after nitrification process.


1995 ◽  
Vol 125 (1) ◽  
pp. 87-93 ◽  
Author(s):  
C. Aguilera-Diaz ◽  
L. Recalde-Manrique

SUMMARYA factorial experiment on Vicia faba L. cv. Alameda with three plant densities at three levels of nitrogen fertilization was done for three years (1984–87) at Granada. Yield varied markedly from 403 to 579 g/m2 between seasons. The mean increase in plant population density from 10 to 16 plants/m2 raised seed yield, but a further increase to 21 plants/m2 did not increase yield significantly. There was, however, considerable variation in the response to increasing density (Dl to D3) within each N level (N0, N1 and N2). Application of 30 kg N/ha at the start of flowering increased mean seed yield only at the lowest plant density and in 1986, but 60 kg N/ha increased yield by 135% on average over the 3 years. The highest N application rate resulted in consistently higher overall yields at each plant density. Leaf area index (LAI) showed a significant increase at 20 seeds/m2 compared with that at 10 seeds/m2 but there was no further increase at 30 seeds/m2. Harvest index (HI) was mainly affected by the annual weather conditions, and ranged from 47–4 in 1986 to 62–6 in 1987. HI was related to the mean temperature at flowering (April).


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