Phytoremediation performance of floating treatment wetlands with pelletized mine water sludge for synthetic greywater treatment

Buckets containing floating reed ( ) simulated floating treatment wetlands (FTWs) and were used to improve the remediation performance of synthetic greywater (SGW). The aim of the study was to investigate the behaviour of FTWs for treatment of key contaminants within artificial greywater. Pelletized ochre based on acid mine water sludge was introduced to selected FTWs, because of its capability in sequestration phosphorus and other trace elements. The impact of the following four operational variables were tested in the experimental set-ups of the FTWs (four replicates each): pollutant strength (high- (HC) and low- (LC) concentrations), treatment time (2- or 7-days of hydraulic retention time (HRT)), presence or absence of macrophytes ( ) and cement-ochre pellets. The results showed that 5 - day biochemical oxygen demand (BOD) and chemical oxygen demands (COD) were significantly (  < 0.05) reduced in all wetlands. Nitrate-nitrogen (NO -N) concentrations were significantly (  < 0.05) higher, and those measurements for PO -P were significantly (p < 0.05) lower than the corresponding ones determined for the influent. The existence of ochre pellets with significantly (  < 0.05) decreased B, Cd, Cr, Cu, Mg, Ni and Zn concentrations, but increased Al, Ca, Fe and K concentrations in the effluent, with the exception of sodium (Na). The FTW performances can be improved by utilising ochre-cement pellets to increase the pH of greywater. The presence of acts as a buffer to neutralise the pH of SGW. Rhizomes and biofilms mitigate increases in turbidity, TSS and colour values. [Abstract copyright: © The Author(s) 2019.

Universal Design for Learning (UDL) in Higher Education: A Case Study in LTH

Universal Design for Learning (UDL) is considered an approach to include all students in the university. UDL is based on three main principles providing multiple means of Engagement, multiple means of representation, and multiple means of action and expression. It is relevant for teachers and departments to focus on more flexibility for students to get the required information, expressing their thoughts and knowledge, and enhancing their motivation to learn. This project aims to investigate the possibility of implementing the UDL in the teaching style of the Faculty of Engineering (LTH), Lund University. Two main approaches were considered in this project. The first one was to interview an expert at LTH about the implementation of UDL at LTH. The second one was to analyze three self-experienced teaching situations according to the UDL guidelines. The results of this project stated that LTH management is considerably serious about UDL, and they already planned a seminar series for training teachers at LTH on how to implement UDL in their course design. The analyses for the three different teaching situations showed that the UDL guidelines provide options for making these teaching and learning experiences much better for both teachers and students. We concluded that the UDL is a vital tool to improve teaching in the higher education sector, in Sweden and worldwide

Impact of storage time on characteristics of synthetic greywater for two different pollutant strengths to be treated or recycled

Storage of greywater is controversial for environmental and health reasons. Artificial greywater was assessed after 2 and 7 days of storage time. Two different greywater pollutant strengths were statistically compared at each storage time. A negative significant (p < 0.05) correlation was evident with increasing storage time for the 5-day biochemical oxygen demand for more than 2 days. However, the concentrations of 5-day biochemical oxygen and chemical oxygen demands reduced significantly at 2 days of storage when compared with freshly prepared greywater. Biodegradability (5-day biochemical oxygen demand/chemical oxygen demand ratio) decreased significantly after storage to between 0.14 and 0.39. The nitrification process was improved significantly with increasing storage time concerning low strength greywater with a significant increase in the removal of ammonia-nitrogen and a non-significant decrease in the removal of nitrate-nitrogen. The correlation was significantly positive between ammonia-nitrogen and 5-day biochemical oxygen demand for stored greywater, while it was significantly negative between total suspended solids and both 5-day biochemical oxygen demand and dissolved oxygen. Significant reductions in colour, total suspended solids and turbidity were correlated positively with storage time. Precipitation of dissolved metals was suspected to occur in storing greywater by binding the inorganic components with the sediment and collide surfaces through adsorption, allowing a significant drop in concentrations of dissolved and undissolved metals with increasing storage time through sedimentation. Synthetic greywater of low mineral pollution had significantly higher removals for almost all concentrations compared with those for high concentrations. More advanced technologies for high trace element removal are required

Recycling of domestic wastewater treated byvertical-flow wetlands for irrigating crops

Due to water scarcity in many semi-arid countries, there is considerable interest in recycling various nutrient-rich wastewater streams, such as treated urban wastewater, for irrigation in the agricultural sector. The aim is therefore to assess if domestic wastewater treated by different sustainable wetland systems (some contaminated by diesel spills) can be successfully recycled to irrigate commercially grown crops such as Sweet Pepper (California Wonder; cultivar of Capsicum annuum Linnaeus Grossum Group) and Chilli (De Cayenne; Capsicum annuum (Linnaeus) Longum Group 'De Cayenne') grown either in compost or sand within a laboratory environment. The objectives were to assess the suitability of the irrigation water for long-term growth when using recycled wastewater, the impact of different treated wastewaters as a function of the wetland type, the impact of treated wastewater volume for irrigation, the suitability of different growth media for vegetable growth irrigated with treated wastewater, the effect of a diesel oil spill on the suitability of the recycled wastewater for vegetable irrigation, the economic return of various experimental systems in terms of marketable yields, the impact of differently treated wastewater on soil and fruit mineral and microbial contamination as a function of the wetland type as well as its operation and management, and the possibility of regenerating Capsicum annuum using the mother plant’s seed and irrigation with recycled wastewater treated by constructed wetlands to obtain a new cultivar adapted to urban wastewater. Vertical-flow constructed wetlands treated the domestic wastewater well, meeting the irrigation water quality standards for most water quality parameters with exception of phosphorus, ammonia-nitrogen, potassium and total coliforms, which showed high values significantly (p < 0.05) exceeding the thresholds set for irrigation purposes. The growth of both Sweet Pepper and Chilli fed with different treated and untreated wastewater types was assessed. A few plants suffered from either a shortage and/or excess of some nutrients and trace minerals. The overall growth development of Sweet Peppers was poor due to the high concentrations of nutrients and trace minerals. However, a high Sweet Peppers 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 irrigated with outflow from 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. In contrast, Chillies did reasonably well but the growth of foliage was excessive and the harvest was delayed. High Chilli yields in terms of economic return were associated with tap water and an organic growth medium, and a wetland with a small aggregate size and short contact time and long resting time with a low inflow loading rate, while the best fruit quality in terms of length, width and weight was observed for plants grown in organic media and irrigated with outflow water from wetlands containing small aggregates with long contact and resting times and fed with a high inflow loading rate (undiluted wastewater), releasing more nutrients into their effluent resulting in a greater marketable profit. Low fruit numbers correlated well with inorganic growth media. Filters contaminated with hydrocarbon were usually associated with a substantially lower Chilli marketable yield than those filters lacking hydrocarbon pollution. Chilli generations were grown successfully when using wastewater treated by constructed wetlands and organic soil. High Chilli generation yields in terms of economic return were associated with wetlands containing small aggregates with long contact and resting times and fed with a high inflow loading rate (undiluted wastewater), releasing more nutrients into their effluent producing the best fruit quality in terms of length, width and weight resulting in a greater marketable profit. Chilli generation plants were grown with considerably shorter heights and produced abundant fruit numbers which were harvested earlier than their mothers due to the reduction of irrigation water volume applied on them compared to their mothers. However, excessive nutrients applied on mother plants via irrigation water resulted in better fruit quality in terms of dimensions and weights compared with their generations, leading to a greater marketable profit. Findings indicate that nutrient concentrations supplied to the crops by a combination of compost and treated wastewater are usually too high to produce a good harvest. However, as the compost was depleted of nutrients after about ten months, the harvest increased for pots that received pre-treated wastewater. The productivity of crops in terms of harvest was independent of the wastewater consumption volume, but may have depended on the water quality. A high yield was related to the most suitable provision of nutrients and trace elements. The mineral content of the organic soil was significantly higher than that for the inorganic soil, before and after irrigation with treated wastewater. No substantial mineral contamination was observed in the soils due to irrigation with treated wastewater. Slight to moderate zinc contamination was detected in harvested fruits based on common standards for vegetables. No bacterial contamination was detected for fruits harvested from plants irrigated with wetland outflow water. In contrast, fruits harvested from those plants irrigated with preliminary treated wastewater showed high contamination by total coliforms, Streptococcus spp. and Salmonella spp., especially for fruits which were located close to the contaminated soil surface. However, findings indicate that vegetables receiving wastewater treated with wetlands can be considered as safe compared to those receiving only preliminarily treated wastewater. The project contributes to ecological sanitation understanding by closing the loop in the food and water chain. Findings will lead to a better understanding of the effects of different wetland treatment processes on the recycling potential of their outflow waters

Highlights of the novel dewaterability estimation test (DET) device

Many industries, which are producing sludge in large quantities, depend on sludge dewatering technology to reduce the corresponding water content. A key design parameter for dewatering equipment is the capillary suction time (CST) test, which has, however, several scientific flaws, despite that the test is practical and easy-to-perform. The standard CST test has a few considerable drawbacks: its lack of reliability and difficulties in obtaining results for heavy sludge types. Furthermore, it is not designed for long experiments (e.g. >30 min), and has only two measurement points (its two electrodes). In comparison, the novel dewaterability estimation test (DET) test is almost as simple as the CST, but considerably more reliable, faster, flexible and informative in terms of the wealth of visual measurement data collected with modern image analysis software. The standard deviations associated with repeated measurements for the same sludge is lower for the DET than for the CST test. In contrast to the CST device, capillary suction in the DET test is linear and not radial, allowing for a straightforward interpretation of findings. The new DET device may replace the CST test in the sludge-producing industries in the future

Assessment of the effluents of Basra City main water treatment plants for drinking and irrigation purposes

A severe water scarcity challenge is facing Iraq, which is predominantly due to the absence of water management policies, negatively impacting the water quantity and quality provision from the Tigris and Euphrates Rivers. Moreover, these practices have led to the intrusion of the Arabian Gulf salinity wedge into the Shatt Al-Arab River (SAR), which is the main water source for most water treatment plants (WTPs) in Basra city. In addition, the inadequate management and operation for most WTPs is another reason for the deterioration of water quality provided to Basra province. Accordingly, the aim of this study is to evaluate the performance of the main WTP within Basra province and to subsequently make recommendations for decision-makers to come up with new management strategies and policies. The effluents from eight WTPs were selected to study the quality of water supply for Basra city during the period between January 2018 and December 2018. The results showed that all WTPs were inadequate to treat raw water for drinking or irrigation purposes mainly due to the very bad raw water quality provided by the SAR as well as the lack of maintenance for such plants, resulting in very low removal efficiencies for various water contaminants

Impact of climate change on wetland ecosystems: A critical review of experimental wetlands

Climate change is identified as a major threat to wetlands. Altered hydrology and rising temperature can change the biogeochemistry and function of a wetland to the degree that some important services might be turned into disservices. This means that they will, for example, no longer provide a water purification service and adversely they may start to decompose and release nutrients to the surface water. Moreover, a higher rate of decomposition than primary production (photosynthesis) may lead to a shift of their function from being a sink of carbon to a source. This review paper assesses the potential response of natural wetlands (peatlands) and constructed wetlands to climate change in terms of gas emission and nutrients release. In addition, the impact of key climatic factors such as temperature and water availability on wetlands has been reviewed. The authors identified the methodological gaps and weaknesses in the literature and then introduced a new framework for conducting a comprehensive mesocosm experiment to address the existing gaps in literature to support future climate change research on wetland ecosystems. In the future, higher temperatures resulting in drought might shift the role of both constructed wetland and peatland from a sink to a source of carbon. However, higher temperatures accompanied by more precipitation can promote photosynthesis to a degree that might exceed the respiration and maintain the carbon sink role of the wetland. There might be a critical water level at which the wetland can preserve most of its services. In order to find that level, a study of the key factors of climate change and their interactions using an appropriate experimental method is necessary. Some contradictory results of past experiments can be associated with different methodologies, designs, time periods, climates, and natural variability. Hence a long-term simulation of climate change for wetlands according to the proposed framework is recommended. This framework provides relatively more accurate and realistic simulations, valid comparative results, comprehensive understanding and supports coordination between researchers. This can help to find a sustainable management strategy for wetlands to be resilient to climate change

Assessment of capsicum annuum L. grown in controlled and semi-controlled environments irrigated with greywater treated by floating wetland systems

Accumulation of trace elements, including heavy metals, were evaluated in soil and fruits of chilli plants (Capsicum annuum L.) grown under both laboratory-controlled and semi-controlled greenhouse location conditions. Chilli plant biomass growth in different development stages and fruit productivity were evaluated and compared with each other for the impact of growth boundary conditions and water quality effects. Treated synthetic greywaters by different operational design set-ups of floating treatment wetland systems were recycled for watering chillies in both locations. Effluents of each individual group of treatment set-up systems were labelled to feed sets of three replicates of chilli plants in both locations. Results revealed that the treated synthetic greywater (SGW) complied with thresholds for irrigation water, except for high concentrations (HC) of phosphates, total suspended soils, and some trace elements, such as cadmium. Chilli plants grew in both locations with different growth patterns in each development stage. First blooming and high counts of flowers were observed in the laboratory. Higher fruit production was noted for greenhouse plants: 2266 chilli fruits with a total weight of 16.824 kg with an expected market value of GBP 176.22 compared to 858 chilli fruits from the laboratory with a weight of 3.869 kg and an estimated price of GBP 17.61. However, trace element concentrations were detected in chilli fruits with the ranking order of occurrence as: Mg > Ca > Na > Fe > Zn > Al > Mn > Cu > Cd > Cr > Ni > B. The highest concentrations of accumulated Cd (3.82 mg/kg), Cu (0.56 mg/kg), and Na (0.56 mg/kg) were recorded in chilli fruits from the laboratory, while greater accumulations of Ca, Cd, Cu, Mn, and Ni with concentrations of 4.73, 1.30, 0.20, 0.21, and 0.24 mg/kg, respectively, were linked to fruits from the greenhouse. Trace elements in chilli plant soils followed the trend: Mg > Fe > Al > Cr > Mn > Cd > Cu > B. The accumulated concentrations in either chilli fruits or the soil were above the maximum permissible thresholds, indicating the need for water quality improvements

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 &lt; 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