Sustainable Water Treatment

Engineering Solutions for a Variable Climate

Miklas Scholz

• Publisher: Elsevier
• Year: 2018
• Print ISBN: 9780128162460
• eBook ISBN: 9780128162477
• Topic: Technology & Engineering
• Subtopic: Chemical & Biochemical Engineering
• Index: Technology & Engineering

Sustainable Water Treatment: Engineering Solutions for a Variable Climate covers sustainable water and environmental engineering aspects relevant for the drainage and treatment of storm water and wastewater. The book explains the fundamental science and engineering principles for the student and professional market. Standard and novel design recommendations for sustainable technologies, such as constructed wetlands, sustainable drainage systems and sustainable flood retention basins are provided to account for the interests of professional engineers and environmental scientists. The book presents the latest research findings in wastewater treatment and runoff control that are ideal for academics and senior consultants.The book offers a challenging, diverse, holistic, multidisciplinary, experimental and modelling-orientated case study, covering topics such as natural wetlands, constructed treatment wetlands for pollution control, sustainable drainage systems managing diffuse pollution, specific applications, such as wetlands treating dye wastewater and ecological sanitation systems recycling treated waters for the irrigation of crops.- Explains the fundamental science and engineering principles behind each topic- Provides an easy-to-understand, descriptive overview of complex 'black box' drainage and treatment systems and general design issues involved- Includes a comprehensive analysis of asset performance, modelling of treatment processes, and an assessment of sustainability and economics

Chapter 1

Introduction to Sustainable Water Management

Abstract

The water industry is changing rapidly, adapting to increased population pressure and climate change. There is considerable pressure on industry and academia to develop sustainable water management strategies and technologies. This chapter briefly highlights a selection of cutting edge research projects highly relevant to sustainable water management. The recognition that droughts and floods will put more strain on society has also been highlighted. Indicating the need for adequate adaptation and mitigation strategies supported by sustainable technology and engineering principles is a special purpose of this chapter. For example, the recycling of wastewater should help to address water shortages in the agricultural sector. Furthermore, a new concept to learn to life with flooding has been introduced. For example, Sustainable Flood Retention Basins have both a flood and diffuse pollution control function. Finally, an integrated approach to sustainable water management in urban and rural areas has been advocated.

Keywords

Domestic wastewater; drought; graywater; hydrology; pond; sustainable drainage; Sustainable Flood Retention Basin; variable climate; water resources engineering; wetland

Summary

The water industry is changing rapidly, adapting to increased population pressure and climate change. There is considerable pressure on industry and academia to develop sustainable water management strategies and technologies. This chapter briefly highlights a selection of cutting-edge research projects highly relevant to sustainable water management. The recognition that droughts and floods will put more strain on society has also been highlighted. Indicating the need for adequate adaptation and mitigation strategies supported by sustainable technology and engineering principles is a special purpose of this chapter. For example, the recycling of wastewater should help to address water shortages in the agricultural sector. Furthermore, a new concept to learn to life with flooding has been introduced. For example, Sustainable Flood Retention Basins (SFRB) have both a flood and diffuse pollution control function. Finally, an integrated approach to sustainable water management in urban and rural areas has been advocated. As an example, the concept of integration of trees into sustainable drainage systems within urban areas has been outlined.

1.1 Water Resources Engineering Solutions for a Variable Climate

The world is changing rapidly. This is also the case for the water industry, which has to adapt to increased population pressure, lack of finances, and climate change. Traditional water resources engineering solutions are often expensive and unsustainable for many case studies. Therefore, there is considerable pressure on industry and academia to develop sustainable water management strategies and technologies.

The author and his research team have acknowledged in this book that traditional civil engineering approaches to water resources management need to be questioned, and more smart answers to a changining world need to be found with the help of other subject disciplines such as ecology, economics, sociology, and computer science. This book can not cover the entire spectrum of sustainable water engineering and management solutions for a variable climate. Therefore, only highlights of cutting-edge research projects relevant to the topic have been selected in this book to outline the topic to interested readers.

The basis of water resources engineering is a good understanding of applied hydrology. The recognition that droughts and floods will put more strain on society should motivate engineers to find alternative sustainable solutions to wastewater treatment and recycling. Recycling of wastewater such as urban water will certainly help to address water shortages in agriculture. The challenge is to produce crops that require less water and do not pose any health risks to the public and animals.

On the other hand, new strategies to learn to life with flooding need to be developed. It has to be recognized that watercourses have multipurpose usages, and that stakeholders have to share these resources more in the future. The same is the case for smaller waterbodies such as ponds in urban areas. An integrated approach to urban water management is likely to benefit society in the long-term.

1.2 Drought Indices and Impacts

A sound understanding of hydrology is essential to practice sustainable water management. Climate change and variability have impact on many decision-making processes. The impact of climate variability on water demand and availability estimations in drylands is substantial. Establishing methods to analyze precipitation and evapotranspiration data sets may generate useful tools that assist in drought recognition and regional variations therein. Therefore, the development of an index that simultaneously integrates both these variables in a climate variability analysis is important.

Mohammed and Scholz (2017) have proposed the alpha and normalized forms of the reconnaissance drought index (RDI) as a single climatic index for the recognition of geographical areas with differing drought characteristics and potential weather variability. The prime application is that the RDI combines in a single index both precipitation and potential evapotranspiration. A more consistent trend of climate variability can be identified by applying time series of different durations of RDI compared to using time series of precipitation and potential evapotranspiration separately.

Sustainable water management of transboundary watersheds is a particular challenge. Recent increases in human activities in shared river basins have unquestionably raised concerns about potential hydrological impacts, especially impacts of dams and large-scale water withdrawal schemes in the highlands. Anthropogenic pressures twinned with drought impacts have exacerbated water management challenges. Chapter 2, Reconnaissance Drought Index, provides a more detailed discussion.

Al-Faraj and Scholz (2014) have assessed the cumulative consequences of upstream anthropogenic pressures and drought spells on temporal river flow regimes for downstream areas (see Chapter 3: Hydrologic Anomalies Coupled with Drought Impact for a River Flow Regime). They were particularly concerned with transboundary challenges and tried to develop a technical framework supporting decision-makers. Findings indicated that anthropogenic river-regulation coupled with the impact of drought periods have noticeably modified the natural flow paradigm. The yearly average runoffs, which are no longer available for the downstream country, have soared to very high levels. More adverse impacts were detected in the nonrainy season. Findings also reveal that damming and considerable water diversion to large-scale irrigation projects in the upstream state are the main regulations affecting the management of shared water resources in the downstream country. The findings will help decision-makers to develop sustainable water management frameworks for shared watersheds.

1.3 Recycling of Domestic Wastewater Treated by Wetlands for Irrigation

The availability of freshwater in many dry regions is an increasing challenge. Therefore, due to water scarcity in many arid countries, there is considerable interest in recycling wastewater streams such as treated urban wastewater for irrigation in the agricultural sector.

Almuktar and Scholz (2016) assessed the contamination of soil and the example crop Capsicum annuum (chilies grown in pots) irrigated by domestic wastewaters and treated by different wetland types (Chapter 4: Mineral and Biological Contamination of Soil and Crops Irrigated With Recycled Domestic Wastewater). Ortho-phosphate-phosphorus, ammonia-nitrogen, potassium, and manganese concentrations in the irrigation water considerably exceeded the thresholds. High water contamination levels by total coliforms, Salmonella spp. and Streptococcus spp. were detected. No mineral contamination was observed in the soils due to irrigation with treated wastewater.

Results also showed that slight to moderate zinc contamination was detected in some vegetables. Potassium accumulation in the yield showed the highest values followed by zinc. In contrast, the lowest mineral accumulation of the yield was observed for iron. No bacterial contamination was detected for fruits harvested from plants irrigated by wetland outflow water. In contrast, fruits harvested from those plants irrigated by 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 preliminary treated wastewater. High 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 a low contact time (Almuktar and Scholz, 2016).

The creation of crop cultivars used to contaminated irrigation waters is a special challenge as discussed in Chapter 5, Recycling of Domestic Wastewater Treated by Wetlands for Irrigation of Two Crop Generations. Therefore, Almuktar et al. (2017) evaluated, if domestic wastewater treated by various wetland systems can be successfully recycled to irrigate generations of commercial crops such as chili grown in compost within a laboratory environment to obtain a cultivar adapted to domestic wastewater. The vertical-flow wetlands treated domestic wastewater well, meeting the irrigation water quality standards for most water quality parameters, except for phosphorus (4.2 mg/l), ammonia-nitrogen (4.2 mg/l), potassium (7.0 mg/l), and total coliforms (69,647 CFU/100 ml), which showed high values significantly exceeding common thresholds set for irrigation applications of 2 mg/l, 5 mg/l, 2 mg/l, and 1000 CFU/100 ml.

Chili generations were grown successfully when applying wastewater treated by wetlands and organic soil. High chili generation yields concerning economic returns were linked 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 with respect to weight, length, and width resulting in a greater marketable profit of about 46% compared with the others. First generation chili plants were grown with considerably shorter heights and produced abundant fruit numbers, which were harvested earlier than their mothers due to the reduction (approximately 55%) of irrigation water volume used for them compared to their mothers. However, excessive nutrients (particularly nitrogen) applied on mother plants via irrigation water resulted in better fruit quality regarding dimensions and weights compared with their corresponding first generation plants, leading to a greater marketable profit by about 25% (Almuktar et al., 2017).

1.4 Constructed Wetlands and Ponds Treating Urban Wastewater

There is uncertainty about the potential benefits and shortcomings of mature constructed treatment wetlands. Therefore, Al-Isawi et al. (2017) compared the performance, design, and operation variables of two wetland technologies treating domestic wastewater with each other. An experimental artificial pond system and a mature experimental vertical-flow constructed wetland system were operated in parallel. The wetland system planted with Phragmites australis (Cav.) Trin. ex Steud. (common reed) was operated between June 2011 and October 2015, while the pond system was only operated between July 2015 and October 2015. Three different types of ponds were compared: ponds with wastewater; ponds with wastewater and reeds; and ponds with wastewater, reeds, and aeration.

Findings regarding the performances of mature wetlands showed that the wetland systems improved the water quality except for ortho-phosphate-phosphorus, where the treatment performance reduced slightly over time. In general, the aerated pond systems showed better treatment performances in terms of ammonia-nitrogen and ortho-phosphate-phosphorus. Both systems were linked with medium to high levels of 5-day biochemical oxygen demand (BOD) removal. The highest chemical oxygen demand (COD) and suspended solids (SS) removals were observed for wetlands in comparison to ponds. Moreover, mature wetlands were better in removing ammonia-nitrogen and ortho-phosphate-phosphorus than ponds unless the ponds were aerated. The nitrate-nitrogen concentration increased in the aerated ponds reflecting the high oxygen availability (Al-Isawi et al., 2017). Readers might refer to Chapter 6, Comparative Study of Domestic Wastewater Treatment by Wetlands and Ponds, for more details.

There is considerable pressure on the waste industry to find sustainable technology applications recycling their waste economically (see also Chapter 7: Graywater Treatment Using Pelletized Mine Water Sludge). Therefore, Abed et al. (2017) considered precipitated ochre waste sludge obtained from a mine water treatment plant as an adsorbent substance for pollutants, since ochre is relatively free from problematic levels of toxic elements, which could impair on the quality of water to be treated. Artificially created ochre pellets from mixing Portland cement with raw ochre sludge were utilized to remediate either high or low contaminated (HC or LC) synthetic graywater (SGW) in mesocosm-scale stabilization ponds at 2-day and 7-day contact times under real weather conditions in Salford, United Kingdom. After a specific retention time, treated SGW was agitated before sampling to evaluate pollutant removal mechanisms (other than sedimentation) such as adsorption by ochre pellets, before replacing the treated water wi...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Dedications
• About the Author
• Preface
• Acknowledgments
• Chapter 1. Introduction to Sustainable Water Management
• Chapter 2. Reconnaissance Drought Index
• Chapter 3. Hydrologic Anomalies Coupled With Drought Impact for a River Flow Regime
• Chapter 4. Mineral and Biological Contamination of Soil and Crops Irrigated With Recycled Domestic Wastewater
• Chapter 5. Recycling of Domestic Wastewater Treated by Wetlands for Irrigation of Two Crop Generations
• Chapter 6. Comparative Study of Domestic Wastewater Treatment by Wetlands and Ponds
• Chapter 7. Graywater Treatment Using Pelletized Mine Water Sludge
• Chapter 8. Dye Wastewater Treatment by Vertical-Flow Constructed Wetlands
• Chapter 9. Shallow Pond Systems Planted With Duckweed Treating Azo Dyes
• Chapter 10. Tree Species for Supporting Sustainable Water Management in Urban Areas in Temperate Climate
• Chapter 11. Classifying Adaptive Sustainable Flood Retention Basins
• Chapter 12. Predicting Dam Failure Risk for Sustainable Flood Retention Basins
• Index