Resilience of green roofs to climate change

The successful management of cities growth rely in part on the maximization of the benefits delivered by the built environment while minimizing the environmental degradation. Circular and resourceful cites are the mainstream for climate change resilience. Green roofs, as a nature-based solution, contribute to climate change adaptation and mitigation through the provision of several ecosystem services. Value of green roofs can be achieved at the level of environmental (e.g., air quality enhancement, carbon sequestration, biodiversity promotion stormwater management, acoustic insulation, and noise reduction), social (e.g., esthetic integration, well-being and life quality, rooftop gardens), and economic (e.g., life span extension, energetic efficiency, energy production, real-state valorization, business development) spheres. Buildup green roof resilience maybe underpinned by the selection of efficient and sustainable components for its installation. This chapter aims at giving an overview on the role of green roofs resilience to climate change, highlighting the provision of services and the mitigation and adaption capacity.info:eu-repo/semantics/acceptedVersio

Treatment of tannery wastewater in a constructed wetlands operating in series with different plant species

The treatment of tannery wastewater has been a very important issue for pollution control in leather producing countries due to its high pollutant content. Biological processes offer a natural way of treating wastewaters, when compared to more aggressive types of treatment. Constructed wetlands can be an alternative to more conventional biological treatment systems. The species Phragmites australis, Typha spp, Scirpus spp. and Phalaris arundinacea are some of the plants frequently used in subsurface flow constructed wetlands. The present study aimed at assessing the performance of constructed wetland systems operating in series for the treatment of wastewater derived from a tannery plant. Pilot units were operated with horizontal subsurface flow and planted with Typha latifolia and Phragmites australis in an expanded clay matrix. They were subject to two different hydraulic loadings: 180mm/d and 60 mm/d. For an hydraulic loading of 180 mm/d, maximum removal efficiencies of 2100 KgCOD/had (48%) were achieved for unit 1 and 1500 KgCOD/had (33%) for unit 2. For an hydraulic loading of 60 mm/d, maximum removal efficiencies of 360 KgCOD/had (66%) were achieved for unit 1 and of 250 KgCOD/had (60%) for unit 2. No significant differences in performance were found between units with different plant species

The effects of tannery wastewater on the development of different plant species and chromium accumulation in phragmites australis

Toxicity tests were performed to assess the effect of tannery wastewater with different treatment levels on two wetland plants, Phragmites australis and Typha latifolia, which are frequently used in constructed wetlands (CWs) for water treatment, and thus deepen the knowledge on their capacity to withstand the application of industrial wastewater. Trifolium pratense, a plant generally used as an indicator in toxicity tests, was included as a control. End points measured were germination percentage, shoot length, root elongation, and biomass growth of the plants. When tannery effluent, with a low treatment level, was supplied to the wetland plants germination occurred even at effluent concentrations of 100%, whereas germination of T. pratense was completely inhibited, almost invariably, at effluent concentration of 50%. Higher germination levels were achieved when the plants were exposed to effluent originating from the outlet of constructed wetland pilot units, allowing germination of all tested plants, indicating a significant decrease in its toxicity level. Experiments conducted with the same plants using different growing substrata as the germination matrix, namely expanded clay aggregates (Filtralite® MR3-8 and Filtralite® NR3-8) and two types of sand (fine gravel and standard sand) have shown that higher germination levels were achieved in standard sand and that P. australis was the plant species showing higher germination in all cases, reinforcing the robustness of this plant to environmental stress. The phytoextraction potential of P. australis, was evaluated by subjecting the plant to tannery wastewater supplemented with 50 and 150 mg Cr/L. After 6 weeks of exposure, levels up to 4825, 883, and 627 mg Cr/kg were found in the rhizome, shoot, and leaves, respectively, although phytotoxic signs in the plant were evident. This plant might not be considered a chromium hyperacumulator, but the potential to extract and accumulate this metal on its rhizomes is high

Evaluation of different substrates to support the growth of Typha latifolia in constructed wetlands treating tannery wastewater over long-term operation

The aim of this study was to investigate the performance of horizontal subsurface flow constructed wetlands planted with Typha latifolia treating tannery wastewater under long-term operation. Two expanded clay aggregates (Filtralite® MR3–8-FMR and Filtralite® NR3–8-FNR) and a fine gravel-FG were used as substrate for the constructed wetland units plus one unit with FMR was left as an unvegetated control. The systems were subject to three hydraulic loadings, 18,8 and 6cm d⁻¹, and to periods of interruption in the feed. The relationship between the substrate, plant development and removal efficiency, especially of organic matter, was investigated. Organic loadings up to 1800 kg BOD5 ha⁻¹ d⁻¹ and 3849 kg COD ha⁻¹ d⁻¹ were applied leading to mass removals of up to 652 kg BOD₅ ha⁻¹ d⁻¹ and 1869 kg COD ha⁻¹ d⁻¹, respectively. The three different substrates were adequate for the establishment of T. latifolia, although the clay aggregates allowed for higher plant propagation levels. The units with FNR and FMR achieved significantly higher COD and BOD₅ removal when compared to the FG and to the unplanted units. The systems proved to be tolerant to high organic loadings and to interruptions in feed suggesting this technology as a viable option for the biological treatment of tannery wastewater

Constructed wetland pilot units for wastewater treatment in the tannery industry

Constructed wetlands can be used for primary and secondary treatment of domestic wastewaters and for the treatment of a variety of other water sources including stormwaters, landfill leachate, industrial and agricultural wastewaters and acid mine drainage. For the treatment of tannery wastewater no detailed studies using constructed wetlands are known in the literature. Frequent problems occur in this industry concerning the effluent with high organic loadings. In these situations, a constructed wetland can be potentially used to support the existing wastewater treatment. The present study refers to the applicability of subsurface horizontal flow constructed wetlands for the treatment of tannery wastewater in two series of pilot units planted with Typha latifolia and Phragmites australis. The units were subject to different hydraulic loadings, 180 mm/d and 60 mm/d, and the organic matter removal efficiency was evaluated. The average COD for the inflow of the units was 1579 mg/l for an hydraulic loading of 180mm/d (1421 KgCOD/had) and 1297 mg/l for an hydraulic loading of 60mm/d (385 KgCOD/had). Maximum removal efficiencies, in terms of COD, for hydraulic loading of 180 and 60 mm/d in Typha unit were 63% and 92%, respectively. For Phragmites, the maximum values were 64% and 92%. The decrease in COD, BOD5 and TSS at the outflow of the units was found to increase with their influent values in a linear correlation. This behavior corresponds to a first order kinetics, showing that the pollutant removal rate was proportional to the influent strength. There was no significant difference between the two systems in series, indicating that the type of plant did not influence the treatment performance

Toxicity abatement of wastewaters from tourism units by constructed wetlands

The present research intended to investigate the toxicity abatement of domestic wastewater after passing a biosystem composed of a constructed wetland (CW) followed by a pond. The wastewater was generated in a tourism house in a rural and mountainous context and passed through a septic tank before being diverted to a CW followed by a pond. A battery of ecotoxicological tests, comprising microalgae (Raphidocelis subcapitata), macrophytes (Lemna minor), cladocerans (Daphnia magna), and bacteria (Aliivibrio fischeri), was used to assess the toxicity of the wastewater collected before and after the CW and the water of the pond. Physicochemical parameters (pH, conductivity, chemical oxygen demand, biochemical oxygen demand, total suspended solids, phosphates, ammonium, and nitrate) were also determined. The CW was able to remove carbon and nutrients from the water with a concomitant reduction of its toxicity. This study, reinforced the added value of using toxicity tests as a complement to CW operational monitoring to validate the solution and to analyze possible readjustments that may be required to improve efficiency. This study lends further support to the claim that CWs can be a sustainable solution for treating small volumes of domestic wastewater in a rural context.info:eu-repo/semantics/publishedVersio

Constructed wetlands as nature-based solutions for wastewater treatment in the hospitality industry: a review

The hospitality industry is increasing its awareness of how the integration of nature-based solutions can decrease its environmental impact while maintaining or increasing the service level of the sector. Constructed wetlands (CWs) constitute a promising sustainable solution for proper in situ domestic wastewater treatment. This literature review elucidates the status of CWs implementation in the hospitality industry to help foster the exchange of experiences in the field and deliver examples of approaches in different contexts to support future applications of this technology. Most of the studies reported in the literature were conducted in Europe, but studies emanating from Asia and South America are also available. The design of CWs, the horizontal and vertical subsurface flow CWs (HSFCW, VSFCW), and hybrid systems have been reported. The average removal efficiencies of the systems ranged from 83 to 95% for biochemical oxygen demand, 74 to 94% for chemical oxygen demand, 78 to 96% for total suspended solids, 75 to 85% for ammonium, 44 to 85% for ammonia, 50 to 73% for nitrate, 57 to 88% for total Kjeldahl nitrogen, 51 to 58% total nitrogen, and 66 to 99% for total phosphorus. The majority of the systems were implemented as decentralized treatment solutions using HSFCWs, with the second most common design being the hybrid CW systems in order to reduce area requirements, increase treatment efficiency, and prevent clogging. Overall, CWs are a promising sustainable solution which may support access to adequate sanitation worldwide as well as safe wastewater recycling and reuse, leading to more sustainable tourist destinations.info:eu-repo/semantics/publishedVersio

Faecal indicator bacteria and listeria monocytogenes in ponds, natural and constructed wetlands: Evaluating water quality

info:eu-repo/semantics/publishedVersio