Suhad A.A.A.N. Almuktar

Rapid expert tool for different professions based on estimated ecosystem variables for retrofitting of drainage systems

There is a need for a geospatial decision support tool for different professions such as drainage engineers and urban planners, which is useful for a quick assessment of the potential of ecosystem services when retrofitting sustainable drainage systems (SuDS) in urban areas. Therefore, the aim of this paper is to develop an innovative rapid decision support tool based on ecosystem service variables for retrofitting of key SuDS techniques by different professionals such as drainage engineers, developers, ecologists, planners and social scientists. This unique and transparent spreadsheet-based tool proposes the retrofitting of a SuDS technique that obtained the highest ecosystem service score for an urban site. This approach is based on a novel ecosystem service philosophy adapted to SuDS rather than on traditional engineering judgement associated with variables based on quick community and environment assessments. For the Greater Manchester example case study area, a comparison with the traditional approach of determining community and environment variables indicates that infiltration trenches, soakaways and belowground storage systems are usually less preferred than permeable pavement systems regardless of the professional perspective. However, ponds also received relatively high scores, because of their great potential impact in terms of water quality improvement and flood control. The estimation of variables was undertaken with high confidence and manageable error.

Experimental Assessment of Recycled Diesel Spill-Contaminated Domestic Wastewater Treated by Reed Beds for Irrigation of Sweet Peppers.

The aim of this experimental study is to assess if urban wastewater treated by ten different greenhouse-based sustainable wetland systems can be recycled to irrigate Capsicum annuum L. (Sweet Pepper; California Wonder) commercially grown either in compost or sand within a laboratory environment. The design variables were aggregate diameter, contact time, resting time and chemical oxygen demand. The key objectives were to assess: (i) the suitability of different treated (recycled) wastewaters for irrigation; (ii) response of peppers in terms of growth when using recycled wastewater subject to different growth media and hydrocarbon contamination; and (iii) the economic viability of different experimental set-ups in terms of marketable yield. Ortho-phosphate-phosphorus, ammonia-nitrogen, potassium and manganese concentrations in the irrigation water considerably exceeded the corresponding water quality thresholds. A high yield in terms of economic return (marketable yield expressed in monetary value) was linked to raw wastewater and an organic growth medium, while the plants grown in organic medium and wetlands of large aggregate size, high contact and resting times, diesel-spill contamination and low inflow loading rate produced the best fruits in terms of their dimensions and fresh weights, indicating the role of diesel in reducing too high nitrogen concentrations.

Vertical-flow constructed wetlands treating domestic wastewater contaminated by hydrocarbons

The aim was to compare the impact of different design (aggregate size) and operational (contact time, empty time and chemical oxygen demand (COD) loading) variables on the long-term and seasonal performance of vertical-flow constructed wetland filters operated in tidal flow mode before and after a one-off spill of diesel. Ten different vertical-flow wetland systems were planted with Phragmites australis (Cav.) Trin. ex Steud. (common reed). Approximately 130 g of diesel fuel was poured into four wetland filters. Before the spill, compliance with secondary wastewater treatment standards was achieved by all wetlands regarding ammonia-nitrogen (NH4-N), nitrate-nitrogen (NO₃-N) and suspended solids (SS), and non-compliance was recorded for biochemical oxygen demand and ortho-phosphate-phosphorus (PO₄-P). Higher COD inflow concentrations had a significantly positive impact on the treatment performance for COD, PO₄-P and SS. The wetland with the largest aggregate size had the lowest mean NO₃-N outflow concentration. However, the results were similar regardless of aggregate size and resting time for most variables. Clear seasonal outflow concentration trends were recorded for COD, NH4-N and NO₃-N. No filter clogging was observed. The removal efficiencies dropped for those filters impacted by the diesel spill. The wetlands system shows a good performance regarding total petroleum hydrocarbon (TPH) removal.

Contaminations of soil and two Capsicum annuum generations irrigated by reused urban wastewater treated by different reed beds

Background: In order to save potable water, this study aims to evaluate the contamination of soil and Capsicum annuum L. (chilli) watered with urban wastewater (sewage) pre-treated by various wetland systems. Methods: The appropriateness of wetland outflow for irrigation when applying reused wastewater with high contamination of minerals and pathogens was assessed. The impact of wastewaters pre-treated by various wetlands on soil and harvest was tested in terms of mineral and biological contamination risk. Results: The wetlands met the standards for irrigation water for most water quality variables. However, the thresholds for key water quality parameters were significantly (p < 0.05) exceeded. The highest values for total coliforms, ammonium-nitrogen, phosphorus and potassium were 157,072 CFU/100 mL, 8.5 mg/L, 5.0 mg/L, and 7.0 mg/L, respectively. The harvest was moderately polluted only by zinc according to vegetable quality standards (threshold of 50 mg/kg). Zinc concentrations for Filters 2, 4, 6, 7 and 8 were 35.8, 60.6, 65.1, 65.5 and 53.2 mg/kg, respectively. No bacterial contamination was detected. Conclusions: Treatment of domestic wastewater applying constructed wetlands and subsequent recycling of the treated wastewater for irrigation of crops is a good substitute to the traditional application of drinking water for irrigation purposes.

Wetlands for wastewater treatment and subsequent recycling of treated effluent: a review

Due to water scarcity challenges around the world, it is essential to think about non-conventional water resources to address the increased demand in clean freshwater. Environmental and public health problems may result from insufficient provision of sanitation and wastewater disposal facilities. Because of this, wastewater treatment and recycling methods will be vital to provide sufficient freshwater in the coming decades, since water resources are limited and more than 70% of water are consumed for irrigation purposes. Therefore, the application of treated wastewater for agricultural irrigation has much potential, especially when incorporating the reuse of nutrients like nitrogen and phosphorous, which are essential for plant production. Among the current treatment technologies applied in urban wastewater reuse for irrigation, wetlands were concluded to be the one of the most suitable ones in terms of pollutant removal and have advantages due to both low maintenance costs and required energy. Wetland behavior and efficiency concerning wastewater treatment is mainly linked to macrophyte composition, substrate, hydrology, surface loading rate, influent feeding mode, microorganism availability, and temperature. Constructed wetlands are very effective in removing organics and suspended solids, whereas the removal of nitrogen is relatively low, but could be improved by using a combination of various types of constructed wetlands meeting the irrigation reuse standards. The removal of phosphorus is usually low, unless special media with high sorption capacity are used. Pathogen removal from wetland effluent to meet irrigation reuse standards is a challenge unless supplementary lagoons or hybrid wetland systems are used.