Effect of primary treatment and organic loading on methane emissions from horizontal subsurface flow constructed wetlands treating urban wastewater

Methane is emitted in horizontal subsurface flow constructed wetlands (HSSF CWs) during wastewater treatment. The objective of this work was to determine the influence of primary treatment and organic loading rate on methane emissions from constructed wetlands. To this aim, methane emissions from a HSSF CW pilot plant were measured using the closed chamber method. The effect of primary treatment was addressed by comparing emissions from wetlands receiving the effluent of an anaerobic (HUSB reactor) or a conventional settler as primary treatments. Alternatively, the effect of organic loading was addressed by comparing emissions from wetlands operated under high organic loading (52 g COD m (2) day (1)) and low organic loading (17 g COD m (2) day (1)). Results showed that methane emission rates were affected by the type of primary treatment and, to a lesser extent, by the organic loading applied. Accordingly, lower redox conditions and slightly higher organic loading of a wetland receiving the effluent of a HUSB reactor resulted in methane emissions twelve times higher than those of the wetland fed with primary settled wastewater. Moreover, systems subjected to three times higher organic loading than that recommended lead to higher methane emission rates, although high data variability resulted in no statistically significant differences.Peer ReviewedPostprint (published version

Reviewing factors affecting the effectiveness of decentralised domestic wastewater treatment systems for phosphorus and pathogen removal

Environmental pollution and risks to human health can result from diffuse sources of pollution originating from decentralised wastewater treatment systems (DWTS). In particular phosphorus pollution can lead to eutrophication and the downgrading of the quality of water bodies, for example, under the Water Framework Directive (WFD) in the EU, and pathogen pollution can result in increased risks of human exposure to pathogens and impacts on industries such as shellfish growing and tourism. The study reported in this paper reviews the effectiveness of various DWTS in removing phosphorus and pathogens from onsite systems. It was found that DWTS are typically not designed to specifically treat these pollutants and the most common type of DWTS, septic tanks, provide only basic treatment. Additional treatment such as filtration-based or wetland systems must be used to achieve desired levels of treatments. The performance of these systems is affected by site specific conditions, such as input load and sources, and climatic conditions and as such operational characteristics and treatment measures must be designed to take account of these factors

Intensified organics and nitrogen removal in the intermittent-aerated constructed wetland using a novel sludge-ceramsite as substrate

© 2016 Elsevier Ltd. In this study, a novel sludge-ceramsite was applied as main substrate in intermittent-aerated subsurface flow constructed wetlands (SSF CWs) for treating decentralized domestic wastewater, and intensified organics and nitrogen removal in different SSF CWs (with and without intermittent aeration, with and without sludge-ceramsite substrate) were evaluated. High removal of 97.2% COD, 98.9% NH4+-N and 85.8% TN were obtained simultaneously in the intermittent-aerated CW system using sludge-ceramsite substrate compared with non-aerated CWs. Moreover, results from fluorescence in situ hybridization (FISH) analysis revealed that the growth of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in the intermittent-aerated CW system with sludge-ceramsite substrate was enhanced, thus indicating that the application of intermittent aeration and sludge-ceramsite plays an important role in nitrogen transformations. These results suggest that a combination of intermittent aeration and sludge-ceramsite substrate is reliable to enhance the treatment performance in SSF CWs

Effects of interspecific competition on the growth of macrophytes and nutrient removal in constructed wetlands: A comparative assessment of free water surface and horizontal subsurface flow systems

© 2016 Elsevier Ltd. The outcome of competition between adjoining interspecific colonies of Phragmites and Typha in two large field pilot-scale free water surface (FWS) and subsurface flow (SSF) CWs is evaluated. According to findings, the effect of interspecific competition was notable for Phragmites australis, whereby it showed the highest growth performance in both FWS and SSF wetland. In a mixed-culture, P. australis demonstrates superiority in terms of competitive interactions for space between plants. Furthermore, the interspecific competition among planted species seemed to cause different ecological responses of plant species in the two CWs. For example, while relatively high density and shoot height determined the high aboveground dry weight of P. australis in the FWS wetland, this association was not evident in the SSF. Additionally, while plants nutrients uptake accounts for a higher proportion of the nitrogen removal in FWS, that in the SSF accounts for a higher proportion of the phosphorous removal

Pilot-scale study on the removal of pharmaceuticals by LECA based SSF-constructed wetlands

In recent years, the occurrence and fate of pharmaceutically active compounds (PhACs) in the aquatic environment has been recognized as one of the emerging issues in environmental chemistry. Some compounds are just resistant to degradation in the sewage treatment plants (STPs) while others, although suffering partial degradation, still end up in receiving water bodies due to the large inputs received in STPs [1]. Clofibric acid (a metabolite from a series of widely used blood lipids lowering agents), ibuprofen (an anti-inflamatory non-prescription drug) and carbamazepine (an anticonvulsant and mood stabilizing drug) are some of the most frequently found PhACs in environmental monitoring studies [1]. Wastewater treatment by sub-surface flow constructed wetland systems (SSF-CWs) is a low-cost technology that has shown some capacity for removal of several organic xenobiotic pollutants, but fewer studies exist on pharmaceuticals behavior. The aim of the present work was to evaluate the efficiency of a pilot SSF-CW assembled with the plants cattail (Typha spp.) and a clay material (LECA 2/4) as support matrix, for the removal of three pharmaceuticals, namely ibuprofen (IB), carbamazepine (CB) and clofibric acid (CA), from contaminated wastewaters. Four beds were planted with pre-grown cattails (density of 80 plants/m2) and four were left unplanted to be used as controls. Experiments were conducted both in batch and in continuous mode with a flooding rate of 100%. Pharmaceutical concentrations were quantified by HPLC with UV detection at 210 nm (CB), 222 nm (IB) and 230 nm (CA). Solid phase extraction was used for sample pre-concentration whenever the measured pharmaceutical concentrations fell under the limit of quantification of the analytical method. The physico-chemical characterization of the support matrix material, LECA, involved the determination of properties such as pH, point of zero charge, electrical conductivity, apparent porosity, bulk density and hydraulic conductivity. In order to shed some light on the tolerance mechanisms developed by Typha spp. in the presence of these pharmaceuticals, biochemical and physiological parameters were evaluated. Typha spp. showed good tolerance to the presence of CA, CB and IB concentrations of 1 mg L-1, which is a value much higher than those usually reported in wastewaters. LECA alone was able to remove about 90% of the initial amounts of CB and IB in solution, and 50% of CA. IB was very susceptible to microbial degradation and up to 80% of the initial concentration could be removed by the microbial population present in the wastewater used. Overall, the CWS shows a higher removal performance for CA, CB and IB than any of its individual components (plants, support matrix, microorganisms) considered separately. CA proved to be the most resilient compound, which comes in agreement with other published data. However, this system enabled the removal of substantially higher amounts of CA than has previously been reported in other studies. The use of systems of this kind for the removal of pharmaceuticals from wastewaters seems like a promising alternative to the less efficient processes of conventional wastewater treatment

Model Fisik Sub Surface Flow Constructed Wetland untuk Pengolahan Air Limbah Musala Al-Jazari Fakultas Teknik Universitas Riau

Musala Al-Jazari is located in the Faculty of Engineering, University of Riau. Activity in musala every day produces a wastewater effluent. Wastewater directly discharged and allowed to seep in flooded soil without first processing that can affect groundwater quality. One of the appropriate technology is simple, inexpensive and easy in operation and maintenance system to reduce pollutants in wastewater was constructed wetland. The purpose of this study is to plan physical model of Sub Surface Flow Constructed Wetland (SSF-Wetland) field scale, determine the effectiveness of SSF-wetland in reducing water waste and calculate budget construction costs SSF-Wetland. Research using medium black soil and water jasmine plants (Alisma plantago). Water quality parameters tested were pH, Chemical Oxygen Demand (COD) and Total Suspended Solid (TSS). The results of the study resulted in the highest efficiency value of 78.07% reduction in COD, TSS of 78.72% and an increase in the pH value of 27.59%. From planning SSF-Wetland obtained the total planned budget of Rp. 6,574,527.16. Overall the results showed that the constructed wetland besides being able to improve the quality of waste water can also beautify the area musala

THE REDUCING OF ORGANIC LOADING AND PHOSPHATE (PO4) IN DOMESTIC WASTEWATER TREATMENT BY CONSTRUCTED WETLAND SYSTEM USING CANNA INDICA AND CYPERUS ALTERNIFOLIUS

The domestic wastewater is mostly produced in settlement areas and usually directly discharged into the environment. Its high organic matter and nutrients will pollute the environment. As an alternative, one of the good wastewater treatment systems is the Sub Surface Flow Constructed Wetland. This system has some advantages such as easy implementation, low cost, and doesn’t need a large area. The aim of this study is to determine the efficiency of Canna indica and Cyperus alternifolius to reduce organic matter and phosphate. This study is an experimental study with two treatments (T1: SSF CW with Canna indica; T2: SSF CW with Cyperus alternifolius). The SSF CW system contains gravels those diameters are 3-5 cm, 1-3 cm, and <1 cm, as well as paddy soil as media with HRT of 3 days. The parameters measured included temperature, BOD, DO, PO4, and pH. Based on this study, it can be concluded that the higher removal efficiency of organic matter is shown by the CW SSF system with Cyperus alternifolius. It is 48,86% in T2 and 42,69% in T1. While the removal efficiency of phosphate in T1 and T2 are 65,70% and 67,21% respectively

THE REDUCING OF ORGANIC LOADING AND PHOSPHATE (PO4) IN DOMESTIC WASTEWATER TREATMENT BY CONSTRUCTED WETLAND SYSTEM USING CANNA INDICA AND CYPERUS ALTERNIFOLIUS

The domestic wastewater is mostly produced in settlement areas and usually directly discharged into the environment. Its high organic matter and nutrients will pollute the environment. As an alternative, one of the good wastewater treatment systems is the Sub Surface Flow Constructed Wetland. This system has some advantages such as easy implementation, low cost, and doesn’t need a large area. The aim of this study is to determine the efficiency of Canna indica and Cyperus alternifolius to reduce organic matter and phosphate. This study is an experimental study with two treatments (T1: SSF CW with Canna indica; T2: SSF CW with Cyperus alternifolius). The SSF CW system contains gravels those diameters are 3-5 cm, 1-3 cm, and <1 cm, as well as paddy soil as media with HRT of 3 days. The parameters measured included temperature, BOD, DO, PO4, and pH. Based on this study, it can be concluded that the higher removal efficiency of organic matter is shown by the CW SSF system with Cyperus alternifolius. It is 48,86% in T2 and 42,69% in T1. While the removal efficiency of phosphate in T1 and T2 are 65,70% and 67,21% respectively

Analisis Luasan Constructed Wetland Menggunakan Tanaman Iris Dalam Mangolah Air Limbah Domestik (Greywater)

Perkembangan penduduk dan ketidakcukupan sarana sanitasi dan instalasi pengolah limbah menyebabkan tingginya pencemaran sungai. Instalasi Pengolah Limbah rumah tangga dipandang mahal dan sulit diterapkan di negara berkembang. Namun, bana buatan (constructed wetland) menawarkan teknologi yang mudah dan murah dalam perencanaan maupun pengoperasian sistem pengolahan air limbah rumah tangga. Dalam penelitian ini dibangun bana buatan dengan sistem sub surface flow (SSF) menggunakan media kerikil dan botol bekas serta tanaman Iris p. dengan ukuran (2 x 1 x 0,650) m3 di sebuah rumah tinggal. Pemilihan tanaman Iris berdasarkan kinerjanya dalam menghilangkan bahan pencemar air limbah serta kemudahannya untuk diperoleh. Tujuan dari penelitian ini adalah mengolah air limbah rumah tangga non-tinja (grey water) untuk mengurangi pencemaran air tanah. Analisis kecukupan luasan dikaji dengan metode Reed, Kadlec dan Knight, serta Crites dan Tchobanoglous. Analisis didasarkan atas penurunan nilai BOD limbah setelah diolah menggunakan bana buatan. Hasil analisis menunjukkan bahwa penurunan BOD dengan waktu tinggal 3 hari mencapai lebih dari 91%, sedangkan luasan yang dibutuhkan antara 1,0 hingga kurang dari 2,5 m2 saja. Hasil tersebut menunjukkan bahwa disain ini bisa diterapkan di halaman rumah tinggal tipe kecil sekalipun