Phosphorus removal from trout farm effluents by constructed wetlands

2001 ◽  
Vol 44 (11-12) ◽  
pp. 55-60 ◽  
Author(s):  
Y. Comeau ◽  
J. Brisson ◽  
J.-P. Réville ◽  
C. Forget ◽  
A. Drizo

Freshwater trout farms need a high and continuous clean water flow to keep fish exposed to a non-toxic ammonium concentration. As a result, the concentration of effluents from these farms are even below standard effluent criteria for municipal wastewater effluent for solids, nitrogen and phosphorus. Nevertheless, the mass of pollutants discharged, originating mostly from excreta and undigested fish food, must be reduced by simple and economical treatment processes. We designed and operated a three-stage system aimed at retaining solids by a 60 μm nylon rotating microscreen followed by treatment with a phosphorus-retaining constructed wetland system. Washwater from the microscreen was pumped to a series of two horizontal flow beds of 100 m3 each (0.6 m deep). Coarse (2 mm) and finer (<2 mm) crushed limestone were used in each bed, respectively, with the first one being planted with reeds (Phragmites australis) and the second one designed to remove even more phosphorus by adsorption and precipitation. Preliminary results indicated that the microscreen captured about 60% of the suspended solids and that greater than 95% of the suspended solids and greater than 80% of the total phosphorus mass loads were retained by the beds. The potential of constructed wetlands as an ecologically attractive and economical method for treating fish farm effluents to reduce solids and phosphorus discharge appears promising.

2007 ◽  
Vol 56 (3) ◽  
pp. 233-240 ◽  
Author(s):  
G. Langergraber ◽  
A. Tietz ◽  
R. Haberl

The multi-component reactive transport module CW2D has been developed to model transport and reactions of the main constituents of municipal wastewater in subsurface flow constructed wetlands and is able to describe the biochemical elimination and transformation processes for organic matter, nitrogen and phosphorus. It has been shown that simulation results match the measured data when the flow model can be calibrated well. However, there is a need to develop experimental techniques for the measurement of CW2D model parameters to increase the quality of the simulation results. Over the last years methods to characterise the microbial biocoenosis in vertical subsurface flow constructed wetlands have been developed. The paper shows measured data for microbial biomass and their comparison with simulation results using different heterotrophic lysis rate constants.


1999 ◽  
Vol 40 (3) ◽  
pp. 265-271 ◽  
Author(s):  
T. O. Okurut ◽  
G. B. J. Rijs ◽  
J. J. A. van Bruggen

The viability of the use of constructed wetlands planted with indigenous Cyperus papyrus and Phragmites mauritianus plants for the purification of pre-settled municipal wastewater in tropical environments was investigated in concrete lined constructed wetlands for a period of 11 months. BOD and total suspended solids concentrations in the effluents from both systems were below 20 mg/l and 25 mg/l, respectively. In the C. papyrus systems, the removal rates for COD, NH4+ and o-PO4− averaged to 3.75, 1.01 and 0.05 (g/m2.day), respectively. In P. mauritianus units, the rates were 1.52, 0.97 and 0.068 (g/m2.day), respectively. A high degree of faecal coliform removal was attained at longer retention times in the two systems.


Author(s):  
Shalini Saxena

Land areas which are wet during part or all of the year are referred as wetlands. Constructed wetlands are manmade systems that mimic the functions of natural wetlands and applied for wastewater treatment. Aim of the present study is to investigate the feasibility of using a Tracheophyte, Phragmiteskarka in constructed wetland for treatment of wastewater in an public park. The daily inlet and outlet wastewater physico-chemical parameters were analysed during the period of two months. The parameters studied were pH, BOD, COD, DO, Total Suspended Solids, Total Dissolved Solids, Nitrogen and Phosphorus. The percentage removal of the parameters were analysed and studied until the percent removal rate gets stabilized. The study showed that the subsurface flow constructed wetlands are best alternative among modern treatments.


1998 ◽  
Vol 38 (12) ◽  
pp. 119-122 ◽  
Author(s):  
V. R. Hill ◽  
M. D. Sobsey

Bacterial, viral and parasitic pathogens in swine wastes are of public health concern because many are able to infect humans. Hence, treatment processes must be effective in removing or destroying these microbes before wastewater discharge. Primary treatment by anaerobic lagoon is the current best management practice (BMP) for swine wastewater in the USA but alternative processes were also investigated for their potential to improve treatment. Wastewater samples were collected approximately monthly from March-December 1997 at a North Carolina swine nursery. Geometric mean concentrations for bacterial indicators (faecal coliforms, E coli, enterococci and C perfringens spores) in lagoon effluent were 3.3×105, 2.8×105, 3.4×105 and 2.2×104 CFU/100mL respectively. For somatic and male-specific coliphages they were 1.4×105 and 5.0×103 PFU/100mL respectively. Bacterial indicator levels in swine lagoon effluents are much higher than allowed for municipal wastewater effluents discharged to land or water. The anaerobic lagoon achieved reductions of 1.1–2.2 log10 for all indicators except C perfringens spores (0.2 log10). Of the secondary treatment processes, constructed wetlands achieved the best indicator microbe reductions ranging from 1.1–2.5 log10. A media filter and an overland flow system achieved mean indicator reductions of only 0.2–1.2 and 0.2–0.8 log10, respectively. The results indicate that a primary-secondary treatment system, an anaerobic lagoon and constructed wetlands, can achieve reductions of 2.9–4.8 log10 for bacterial and viral indicators and 1.5 log10 for C perfringens spores.


2005 ◽  
Vol 51 (9) ◽  
pp. 213-223 ◽  
Author(s):  
G. Langergraber

Plants in constructed wetlands have several functions related to the treatment processes. It is generally agreed that nutrient uptake is a minor factor in constructed wetlands treating wastewater compared to the loadings applied. For low loaded systems plant uptake can contribute a significant amount to nutrient removal. The contribution of plant uptake is simulated for different qualities of water to be treated using the multi-component reactive transport module CW2D. CW2D is able to describe the biochemical elimination and transformation processes for organic matter, nitrogen and phosphorus in subsurface flow constructed wetlands. The model for plant uptake implemented describes nutrient uptake coupled to water uptake. Literature values are used to calculate potential water and nutrient uptake rates. For a constructed wetland treating municipal wastewater a potential nutrient uptake of about 1.9% of the influent nitrogen and phosphorus load can be expected. For lower loaded systems the potential uptake is significantly higher, e.g. 46% of the nitrogen load for treatment of greywater. The potential uptake rates could only be simulated for high loaded systems i.e. constructed wetlands treating wastewater. For low loaded systems the nutrient concentrations in the liquid phase were too low to simulate the potential uptake rates using the implemented model for plant uptake.


HortScience ◽  
2008 ◽  
Vol 43 (3) ◽  
pp. 868-874 ◽  
Author(s):  
Robert F. Polomski ◽  
Douglas G. Bielenberg ◽  
Ted Whitwell ◽  
Milton D. Taylor ◽  
William C. Bridges ◽  
...  

Intensive production of container-grown nursery and greenhouse crops in soilless substrate may result in significant leaching of nutrients and pesticides. The resulting runoff can escape from production areas and negatively impact surface and ground water. Constructed wetlands (CWs) have been shown to be a simple, low-technology method for treating agricultural, industrial, and municipal wastewater. We investigated the nitrogen (N) and phosphorus (P) removal potential by a vegetated, laboratory-scale subsurface flow (SSF) CW system. Over an 8-week period, five commercially available aquatic garden plants received a range of N and P (0.39 to 36.81 mg·L−1 N and 0.07 to 6.77 mg·L−1 P) that spanned the rates detected in nursery runoff. Whole plant dry weight was positively correlated with N and P supplied. Highest N and P recovery rates were exhibited by Thalia geniculata f. rheumoides Shuey and Oenenathe javanica (Blume) DC. ‘Flamingo’, Phyla lanceolata (Michx.) Greene also had high P recovery rates. The potential exists for using SSF CWs to concomitantly produce aquatic garden plants and attenuate nutrients in a sustainable nursery enterprise.


1993 ◽  
Vol 28 (7) ◽  
pp. 1-7 ◽  
Author(s):  
Chiu-Yang Chen

The objective of this study is to evaluate the effectiveness of primary treatment on municipal wastewater before it is discharged into the ocean. A series of filter papers of specified pore size was applied to measure the removal of organics and solids in wastewater through various primary treatment processes. For plain sedimentation, the removal of suspended solids was always less than 50% while COD and BOD removals were 23-41% and 15-27%, respectively. For chemical coagulation with the addition of poly aluminium chloride (PAC), 70% SS removal was obtained with a PAC dose of 30 mg/l. If polyelectrolyte is added (about 1 mg/l), the dosage of PAC can be reduced to around 10 mg/l to maintain the SS removal efficiency at the same level. For air flocculation treatment by preaeration followed by sedimentation, the most achievable removal of solids from wastewater of more than 80% was obtained at an aeration rate of 0.5-1.0 Nl air/l. In particular it is more effective for smaller solids than for larger solids in wastewater. On organic removal, about 15-40% removal in terms of COD or BOD was obtained by treating wastewater with either plain sedimentation or air flocculation and sedimentation processes. The efficiency of organic removal from wastewater increased to about 60% by utilizing chemical coagulation and sedimentation treatment. Based upon the characteristics of tested municipal wastewater, in order to maintain the SS removal at 65% or above as regulated, the treatment processes of chemical coagulation or air flocculation followed by sedimentation should be employed.


2006 ◽  
Vol 5 (4) ◽  
pp. 685-692
Author(s):  
Elisabeta Chirila ◽  
Ionela Carazeanu Popovici ◽  
Techin Ibadula ◽  
Alice Iordache

1997 ◽  
Vol 32 (1) ◽  
pp. 101-118 ◽  
Author(s):  
Q.J. ROCHFORT ◽  
W.E. Watt ◽  
J. Marsalek ◽  
B.C. Anderson ◽  
A.A. Crowder

Abstract Two subsurface flow constructed wetlands were tested for pollutant removal performance in conjunction with an on-line stormwater detention pond, in Kingston Township, Ontario. The 4.9 m2 wetland cells were filled with 9 mm limestone gravel, and planted with cattail, common reed and spike rush. Changes in nutrient (total organic carbon, PO43- and NH4+), suspended solids and metal (Cu, Pb, Zn) concentrations were used to assess performance. Contaminant removal occurred through a combination of physical, chemical and biological means. As with any biological system, variation in performance of stormwater wetlands can be expected to occur as a result of fluctuations in contaminant loading, contact time and ambient environmental conditions. Storm pond effluent was delivered in continuous flow through the wetlands (during baseflow and event conditions), with a detention time of 1 to 3 days. The wetlands were able to maintain removal rates of up to 39% for orthophosphate even during the more severe conditions of fall dieback. Average removal of suspended solids (46%) and dissolved metals (Cu 50%) remained similar throughout all tests. Organic carbon was reduced by less than 10% during these tests. Low nutrient levels in the pond effluent were supplemented by spiking with sources of carbon, nitrogen and phosphorus during pulsed loading conditions. Daily sampling produced a time series, which illustrated the rates of decline in concentration of nutrients. First order kinetic assimilation rates ranged from 1.7 d-1 for NH4002B to 0.12 d-1 for organic carbon, which were noticeably lower when compared with municipal and industrial wastewater treatment rates. Three methods of sizing stormwater wetlands (impervious surface area, volumetric load and kinetic reaction rates) were compared using the same design storm and data from this study. From this comparison it was seen that the kinetic sizing approach proved to be the most versatile, and allowed for adaptation to northern climatic conditions and anticipated nutrient loading.


1995 ◽  
Vol 31 (10) ◽  
pp. 103-121
Author(s):  
J.-O. Frier ◽  
J. From ◽  
T. Larsen ◽  
G. Rasmussen

The aim of waste modelling in aquaculture is to provide tools for simulating input, transformation, output and subsidiary degradation in recipients of organic compounds, nitrogen, and phosphorus. The direct purpose of this modelling is to make it possible for caretakers and water authorities to calculate waste discharge from existing and planned aquaculture activities. A special purpose is simulating outcome of waste water treatment and altered feeding programmes. Different submodels must be applied for P, N, and organics, as well as for the different phases of food and waste treatment. Altogether this calls for an array of co-operating submodels for a sufficient coverage of the options. In all the required fields there is some scientific background for numerical model approaches, and some submodels have been proposed. Because of its multidisciplinary character a synthesized approach is still lacking. Within trout farming this work attempts to establish the different submodels and outlines future possibilities for synthesizing the knowledge to a numerical model.


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