Emerging Technologies in Biological and Hybrid Wastewater Treatment: Lessons from Developed to Enhancing Practices in Developing Countries

Refractory organic contaminants in significant amounts have recently entered wastewater treatment facilities from different sources. These contaminants are usually found in modest concentrations and have been dubbed “emerging contaminants” as they are recalcitrant to conventional biological treatments. These contaminants originate from different sources, including industrial chemicals, pharmaceuticals, personal care products, and agricultural runoff, and necessitate advanced treatments for their removal from the waste streams. Hence, hybrid treatment technologies work in conjunction with contemporary traditional treatment technologies that might serve the intended purpose of removing these contaminants of emerging concern. The present chapter dives deeply into understanding the various sources and types of emerging contaminants that enter wastewater treatment plants together with wastewater, and emphasis is given to the implications of these trace organic contaminants on the operation of conventional treatment systems. Special emphasis is given to the necessity of implementing alternative and sustainable hybrid technologies and present a brief overview of the latest state-of-the-art advancements in this field. This chapter addresses the current state of wastewater treatment, provides background information and an overview of the topics covered in this book. Furthermore, this chapter emphasises the necessity of a biological-hybrid treatment system for the efficient treatment of wastewater generated from various sources to preserve the water quality in the receiving water bodies and safeguard aquatic life.

Trace organic contaminants like pharmaceuticals, pesticides, surfactants, and phenolic compounds impose a threat to human health as well as aquatic plants and animals. A significant source of these contaminants entering the aquatic ecosystem is through the discharge of sewage from households, veterinary, agricultural runoff, pharmaceutical industries, and others. Besides, biological treatments are cost-effective and environmentally friendly technologies for wastewater treatment. Thus, it is essential to discuss and compare the traditional biological technologies that effectively treat trace organics from sewage. Different microbes present in the biological setups might break these organics into more environmentally liable and non-toxic compounds. However, further development of efficacious biological technologies is crucial for future full-scale application and commercialization. Therefore, this chapter deals with the technologies, such as activated sludge process, trickling filter, up-flow anaerobic sludge blanket reactor, stabilization ponds, and others used to remove organics present in the wastewater. The factors impacting the removal efficiency, like organic loading rate, and hydraulic retention time have also been elucidated. In addition, the mechanism of removal of organics in traditional biological technologies is comprehensively discussed. Lastly, the need for hybrid treatment technologies for remediation of organic pollutants has been discussed.

The growing need for a reliable water supply has outstripped the availability of modern technologies for water treatment. Advanced water treatment methods using membranes have a strong track record of producing clean water. This chapter aims to present the progress of membrane technology and its applications, types; challenges, and the necessity to develop membrane technologies for long-term water treatment. By collecting the literature about membrane technology, the process description and its applications, advantages and disadvantages, investigation of monitoring and control the membrane technologies and comparing with different types of membrane bioreactors and how to improve the efficiency of membrane technology while reducing the adverse impacts. on the environment. While there is a huge attention to green and sustainable membranes, also, analysis of membrane materials and several factors affecting its efficiency such as fouling or toxicity of contaminants so there is a need for further studies to be done and it will be discussed on this chapter. Therefore, many traditional membrane synthesis methods are presented in this chapter. In recent years, various sustainable alternatives have been proposed. In addition, this chapter will examine some of the latest developments in membrane technology for desalination and wastewater treatment in order to improve membrane sustainability. Some of the current trends in membrane science and technology for sustainable water treatment include membrane reuse, the reuse of wasted brine or sludge, the collection of energy from waste, and the application of membrane antifouling techniques to reduce waste. Concluded at last how emerging membrane technology has a promising future for water purification and treatment.

Creating wastewater from olive oil mills (OMW) represents a real environmental challenge in food manufacturing. These wastewater effluents contain several complex components. This study investigated the capacity of a sequential batch reactor (SBR) to treat diluted olive oil mill wastewater in conjunction with domestic sewage. The study examined two OMW dilutions. The D1 dilution increased OMW biodegradability and reduced pollution. The efficacy of each reactor in reducing pollution from both dilutions was monitored throughout the experiment. Both systems operated on a continuous 24-h repeating procedure. The SBR D1 showed considerable reductions in COD, polyphenols, nitrates, ammonium, and phosphorus, reaching 68.9%, 67.1%, 75.3%, and 95.3%, respectively. In contrast, 40.2%, 47%, 61.2%, 61.1%, and 94.1% of COD, polyphenols, nitrates, ammonium, and phosphorus, respectively, were removed by SBR D2. The proposed treatment method represents a simple, cost-effective process that could be used in the olive oil sector.

Industrial wastewater commonly contains a lot of pollutants, which contributes to eutrophication in aquatic systems. To improve the treatment of vegetable oil refining wastewater, we investigated the potential of a biological treatment, precisely an aerobic-anoxic sequencing batch reactor system. The reactors were operated on a 24-h cycle, consisting of 20 min for filling, 17 h for aeration, 4 h for anoxic conditions, 2 h for settling, 20 min for draw, and 20 min of idle time. Results showed removal efficiencies of 83%, 94%, 80%, 93%, 96%, and 91% for COD, BOD₅, turbidity, nitrate, ammonium, and phosphate, respectively. Despite its complexity, the SBR biological reactor is considered a promising solution for industrial wastewater treatment. The O/A-SBR system is an effective treatment process for the vegetable oil refining industry.

The ecosystem is severely harmed by industrial pollution discharges from wastewater from cleaning fuel oils, especially the maritime environment that receives these discharges. The effectiveness of biological treatment of fuel oil washing wastewater using a sequential batch reactor (SBR) is assessed in this work on a laboratory scale. The sequential batch reactor experiment for fuel-washing wastewater lasted 25 days, operating continuously in a 24-h cycle (with 30 min of filling, 17 h of aeration, 4 h of anoxia, 2 h of settling, and a final 30 min of emptying). To evaluate how effectively the fuel oil washing wastewater treatment process worked, key pollution indicators including turbidity, total suspended particles, chemical oxygen demand (COD), biological oxygen demand (BOD5), ammonium, and nitrate were measured. The removal efficiency of COD is 81%, BOD5 91%, TSS 72%, ammonium 100%, and nitrate 52%. The treatment of industrial wastewater from fuel oil washing wastewater of SBR-type discharges could be a potential approach to limit pollution because of its simplicity, low environmental impact, low energy consumption, and lack of requirement for highly qualified workers.

Treating the Wastewater produced in domestic or industrial source has been a practice associated with the human civilization since early stages and continues to be relevant in modern society. The primary focus of wastewater treatment is the removal of nutrients, specifically nitrogen and phosphorus. These nutrients are present in effluents and their presence can lead to eutrophication in water bodies in the natural environment. Nutrient removal techniques have evolved from primitive techniques to the most advanced methodologies historically. The incorporation of scientific knowledge has played a vital role in the modernization of wastewater treatment technologies just like in most modern technologies we enjoy. The objectives of nutrient removal from wastewater have significantly shifted from the sole aim of safeguarding public health and preventing diseases to encompass sustainable initiatives, such as resource recovery from wastewater. This book chapter provides a comprehensive discussion on emerging technologies designed to improve nutrient removal in wastewater treatment systems. Transition from traditional nutrient removal methods to contemporary techniques is also important for any professional who is looking in to learn about the wastewater technologies, which will be thoroughly explored, providing insights into the underlying mechanisms and highlighting the associated advantages and implementation challenges. Additionally, this chapter delves into the investigation of high-rate nutrient removal systems that have proven successful in full-scale wastewater treatment plants. Understanding the notable advancements achieved in conventional wastewater treatment is another important area that will be covered in this chapter. Under the recent advancements, implementation of advanced initiatives, including granular biomass systems, sequencing batch reactors (SBRs), wetland treatment, integrated up-flow anaerobic sludge blanket (UASB) systems, and short aerobic systems will be discussed. Microbial consortia are utilized to remove nutrients in wastewater as an effective strategy. Present trend is to focus on further enhancing the efficiency and economy of biological nutrient removal from wastewater, aligning with sustainable initiatives. Key areas of interest are biological phosphorus removal, biofilm technology for water treatment, and the utilization of microalgae which have been covered in this chapter.

The main aim of this study was to investigate the enhanced performance of a horizontal subsurface flow constructed wetland (HSSFCW) in terms of nitrogen and organics removal through a proper spatial distribution of aeration to ensure simultaneous aerobic and anaerobic conditions. Two HSSFCWs, one aerated in its front section only and the other one non-aerated (as control), were operated in parallel at a hydraulic retention time (HRT) of 24 h, a hydraulic rate (HLR) of 0.16 m day and a water depth of 0.4 m. Three distinct types of synthetic effluents were prepared and fed in the systems to simulate a wide range of wastewaters. The rate of aeration provided in the aerated (or intensified) bed was also varied to assess its impact on the intensified removal of ammonium-N (NH₄-N) and chemical oxygen demand (COD).The enhanced performance of the aerated bed, when compared to the non-aerated one, in terms of COD, NH₄-N and total nitrogen (TN) removal efficiency were found to be 26.0 ± 14.7% (N = 68), 61.6 ± 11.7% (N = 60) and 18.2 ± 5.5% (N = 60), respectively. Aeration did impact significantly (p < 0.05) and positively on the aerated bed performance in terms of COD and NH₄-N removal efficiency. The rate constant of COD and NH₄-N degradation in the aerated bed were 3 times and 10 times higher than in control bed, indicating that aeration indeed enhanced the performance of HSSFCW. This study shows that without aeration, such a natural treatment system may not be capable of effectively treating medium to high strength wastewater. This aeration strategy had overcome its oxygen transfer limitation and will constitute a sustainable solution to treat different kind of wastewater with high organic and nitrogen concentration.

Wastewater treatment is an energy- and resource-intensive process due to the necessity to meet the effluent discharge standards. Besides, wastewater contains substantial quantities of valuable resources, mainly carbon, nitrogen, and phosphorous, which could be recovered and recycled for secondary applications. Furthermore, resource recovery from wastewater leads to positive economic and environmental impacts while enhancing the sustainable maintenance of a circular bioeconomy. Among various techniques, algae-based wastewater treatment has gained attention in recent years due to sustainable, low-cost, and highly efficient treatment. In general, the proliferation of algae provides the oxygen needed for the degradation of organic compounds by anaerobic microorganisms, which simultaneously provide the carbon dioxide required for algal photosynthesis. Meanwhile, solar irradiation with elevated oxygen and pH, resulting from algal photosynthesis, enhances the disinfection of pathogens in wastewater. Thus, algae cultivation is being immensely exploited in primary, secondary, and tertiary stages of wastewater treatment plants, which has demonstrated significantly high removal efficiencies of pollutants, nutrients, and pathogens, which consequentially lead to advanced wastewater treatment. In addition, algae biomass generated from wastewater-based cultivation contains high-value metabolites, namely lipids, proteins, carbohydrates, and carotenoids, among others, which are beneficial in biorefining value-added products, such as food/feed, biofuels, biofertilizers, biopolymers, etc. Nevertheless, there are challenges associated with coupling wastewater treatment and algal cultivation including, but not limited to, maximizing biomass yields and enhancing nutrient removal rates, to develop commercially viable full-scale treatment systems. In this context, the current chapter holistically scrutinizes the prospects of integrating algae cultivation in wastewater treatment plants for efficient energy and resource recovery while focusing on the techno-economic feasibility of algae-based technologies.

The presence of pharmaceutical compounds (PCs) in aqueous systems poses a significant threat to ecological systems. Additionally, antibiotic contamination poses a risk to microbial communities and human health. If antibiotic-resistant bacteria develop, this could lead to an increase in multi-resistant bacterial infections in the coming days and have serious consequences for human health, ecosystems and the environment. One of the most prospective approaches consists of combining biological and physicochemical methods to treat these effluents. Accordingly, hybrid systems must be fabricated by mixing biological and physicochemical methods. In some cases, these hybrid processes help improve pharmaceutical disposal performance by overcoming each disadvantage of one method over the other. They appear to be a potential means of reducing the impact of pharmaceutical emissions on the environment, ecosystems, wastewater treatment plants and public health. This is about better and more sustainable management of this complex environmental issue.

An optimization study using composite central designs, responce surface methodology, and Analysis of Variance (ANOVA) was conducted to treat olive oil mill wastewater using Moringa oleifera. This study uses the natural coagulant Moringa oleifera, to explore the coagulation-based treatment of OMW. Process optimization is accomplished by combining the response surface methodology (RSM) with central composite design (CCD). This process examines at four factors: pH, agitation speed, duration, and concentration of Moringa oléifera, in order to determine the relationship between Turbidity, COD, and polyphenols. The models’ significance is verified by the ANOVA. The study's highly adjusted coefficient of determination (R2Adj = 86.73%, R2Adj = 90.39%, and R2Adj = 93.33% for turbidity, COD, and polyphenols, respectively) indicates a strong model fit. Moreover, the following conditions are shown to be optimal for achieving effective OMW purification with Moringa oleifera: Moringa oleifera concentration [Mo] = 65 g/L, pH = 6, agitation time (St) = 25 min, and speed (Ss) = 35 rpm. Turbidity removal efficiency is 96%, COD removal efficiency is 88%, and polyphenol removal efficiency is 86% at these optimal conditions. To sum up, this method provides a practical way for addressing the environmental issues that OMW raises.

Bangladesh's primary source of foreign exchange earnings is the textile sector, employing over three million women. The industry’s unexpected growth has led to adverse repercussions on the environment, shown by the release of untreated textile wastewater into aquatic bodies. Compliance concerns emerge due to the exorbitant expenses associated with treatment, which result from the utilization of expensive imported chemicals and reliance on energy-intensive equipment. A series of technology development projects were conducted at the bench and field scale to find an environmentally friendly approach for treating textile effluent utilizing materials and chemicals that are readily available in the local supply chain. The process involved chemical oxidation using calcium hypochlorite followed by waste blast furnace iron slag- aided micro-filtration. Complete removal of color, reduction in Chemical Oxygen Demand (COD), Total Dissolved Solids (TDS), and Total Suspended Solids (TSS) were achieved, producing waster in compliance with the discharge limits for both as a pretreatment option and as final polishing post-tertiary treatment. The developed process, reliant on locally available resources, has the potential to serve as a sustainable textile wastewater treatment option for resource-challenged Bangladesh and other resource-limited economies in South Asia. Implementing the developed process may help achieve Sustainable Development Goals.

Scientific innovators have provided the inhabitants of Earth with a better quality of life. However, sometimes the road to self-destruction is paved with good intentions. Humankind is under existential threat. The burning issue on planet Earth is now the mitigation of climate change and sustaining our lifestyle with less energy, materials, and other factors of production. This chapter aims to guide process designers in treating textile processing wastewater in a less energy-intensive manner with a lower carbon footprint and reusing the wastes that have been rejected in various biological and chemical processes. The second law of thermodynamics explains how much materials or energy are wasted in the transformation processes. The objective is to recover the potential material or energy and reuse it to achieve Sustainable Development Goals. Circular economy of wastewater treatment and how waste by-products from textile processing wastewater treatment plants can be turned into value-added components to build sustainability. In this regard, wastewater recycling will be treated substantially by discussing technologies and processes available and the economy—examples of smart operating facilities where wastewater is turned into assets.

Wastewater treatment methods aim to protect public health and the environment by removing contaminants and preventing water pollution of natural water bodies. Most of the existing treatment methods, inclusive of the costly high-tech methods, are mostly focused on single-objective, end-of-pipe solutions devised under linear production and consumption framework. Such approaches are categorized as lower-order strategies under the concept of circular economic principles which present also a set of higher-order circulatory strategies to effectively maximize resource efficiency whilst minimizing waste generation. This chapter focuses on opportunities for application of higher-order circulatory strategies in wastewater treatment, and demonstrates its viability via a case study from vernacular settlements of Sri Lanka, known as the Ellangava system. An ellangava system is an ensemble of multi-objective, ecologically-comprehensive, expansive subsystems weaved together towards effectively employing cost-effective ecological services to enhance water quality and to ensure its availability throughout the year. We extend the discussion to identify the advantages of subsystems contribution in achieving the ecosystem sustainability goals in wastewater treatment through a roadmap.

Untreated greywater that negatively impacts our environment is directly discharged even though it has the potential to be treated. Unlike traditional wastewater which requires a large-scale centralized treatment plants with huge infrastructural costs, greywater can be treated in a small-scale manner for use in irrigation. Hence, this chapter examines the primary quality of greywater present in Chattogram city by conducting an environmental assessment. 10 greywater samples were collected for chemical analysis and 5 for microbial examination from 5 different locations in Chattogram City. Water parameters like pH, Total Dissolved solids (TDS), Electrical conductivity (EC), Total hardness, Dissolved Oxygen (DO), Oxidation–Reduction potential, and other chemical analysis such as fluoride, chloride, phosphates, Sulphate, and nitrate levels were tested. Total coliforms and fecal coliforms were also evaluated through MPN tests and again cultured on EMB agar. Water parameters like Total hardness, Fluoride, Nitrates, and Sulfates conformed international standards which makes the water suitable for reuse. However, due to the exceeded turbidity and chloride levels found in the greywater, targeted treatment procedures are necessary for its reuse in irrigation. All samples were found to be contaminated with fecal matter (10⁴ CFU/100 ml) and total coliform (1100 CFU/100 ml) that could cause diseases. In this regard, the chapter further reviews low-cost treatment systems from Kenya, India and Egypt which could be used in a developing country like Bangladesh. Moreover, this chapter gives recommendations for proper management approaches towards greywater reuse.

Nutrient (nitrogen and phosphorus) removal from wastewater is becoming even more important due to climate change. The basic principles of both aerobic and anaerobic processes, including microbiological characteristics for industrial, stormwater and municipal wastewater systems are described. Nitrogen removal is often a two-step process including nitrification and denitrification. More recent attention has been given to the annamox process, an anaerobic ammonium oxidation process that converts ammonia and nitrite to nitrogen gas without the addition of carbon containing compounds. A combination of aerobic and anaerobic conditions is needed for phosphorus removal. In addition, combined nitrogen and phosphorus systems can also be considered. Various reactor configurations are described for nutrient (nitrogen and/or phosphorus) removal including aerated tanks, sequencing batch reactors, biofilters, fixed film, UASB, airlift, and membrane bioreactors, among others. Applicability, design parameters, monitoring, maintenance, and operational requirements for each reactor type are discussed. In addition to conventional nutrient removal processes, nature-based solutions such as wetlands will be described. Challenges and future research directions are identified.

Antibiotic resistance genes (ARGs) as emerging contaminants (ECs) of concern, has raised alarming health concerns globally across geographical locations. Municipal wastewater treatment plants (WWTPs) have emerged as a significant cause for these ARGs and associated antibiotic-resistant bacteria (ARBs). WWTPs receives an influx of antibiotics from a plethora of anthropogenic sources ranging from municipal wastes, livestock wastes, hospitals, and pharmaceutical manufacturing industry. Conventional treatment methods have shown limited capabilities in effectively removing these emerging contaminants ranging from antibiotic residues, active pharmaceutical ingredients (APIs) and ARGs. It puts selection pressure on the proliferating microbes to develop antimicrobial resistance (AMR) and aid in their distribution through the system into the environment. Various disinfection methods have been implemented to remove ARGs in WWTPs such as chlorination and UV to eliminate microbial loads in wastewater, but ARGs have been shown to be persistent and survive these conventional treatments. In recent times, advanced oxidation processes (e.g. Ozone, UV/H₂O₂, Fenton) have gained attention due to their increased efficacies in ARG abatement, albeit showing variable results. However, adequate data on the effect of influencing factors on the occurrence, dissemination, and fate of ARGs is lacking in the literature. Therefore, the key objective of this review chapter is to provide a comprehensive overview of the fate of ARGs in WWTP systems and discuss the influence of operational factors and the efficacy of treatment technologies regarding its mitigating potential. In addition, current challenges pertaining to AOPs are discussed, and key knowledge gaps are suggested for future research which could aid in better understanding the impact of influencing factors on the ARGs fate during implementation of various AOPs.

The efficacy of wastewater treatment technologies is primarily evaluated based on their ability to remove the desired contaminants. Once, the performance parameters are established, attention is paid to the economic feasibility of the field scale application of the technology. However, in the present era of awareness, a third evaluation criteria alternate to the technical feasibility and economic suitability of the treatment options, is the consideration of the environmental sustainability. The impacts of a technology application are not only limited to receiving water systems in concern to removal of contaminants present in wastewater. With a wide vision, the impacts encompass the effect of the technology on the flora and fauna, human health, and the exploitation of natural resources. This is an upcoming parameter of consideration for evaluation of new technologies as well as upgradation of existing options for wastewater treatment. One such tool is the life cycle assessment (LCA), which evaluates the impacts associated with a process/technology inclusive of the material and energy consumption and the overall emissions. Various studies have carried out LCA for lab-scale or field scale treatment technologies. LCA studies can estimate significant environmental parameters such as global warming potential, eutrophication, ozone layer depletion, water consumption, land utilization, etc. This book chapter will provide views and discussion on the potential of LCA as a tool for evaluation of various wastewater treatment technologies.