Conventional Wastewater Treatments

Conventional wastewater treatment consists of chemical, biological, physicochemical, and mechanical processes to remove organic loading, solids, and nutrient contents from wastewater. Biological processes are more commonly used in wastewater treatment as secondary or tertiary treatments, as it is more effective and more economical than chemical and mechanical processes. In this chapter, several types of wastewaters generated from municipal or industrial activities are discussed. Wastewater has different pollutant contents depending on the point of generation which consequently requires different ways of treatment. Some commonly used conventional wastewater treatment technologies are introduced. A particular focus is given to both aerobic and anaerobic treatments.

Conventional Water Treatments

Conventional water treatments have several successive processes in series to produce potable water. This chapter talks about the conventional water treatment processes which are mainly used to treat water originated from freshwater sources. Besides, the discussion covers some typical water quality, both raw and treated, as well as the standards of water quality. One of the highlighted topics in this chapter is the common issues that are frequently happening in the conventional water treatment facilities around the rural regions experiencing tropical climate, which is centred on the issues affecting the raw water quality and treatment processes. The major issue during post-treatment which is on sludge management is also discussed by underlining some alternative to the traditional way of using sludge lagoons. Topics in this chapter provide a better perspective to the water treatment operators and students who are interested in this topic of major processes used in conventional water treatment plants as well as the common issues encountered.

Mass Transfer Phenomenon and Transport Resistances in Membrane Separation

The inevitable decline of membrane performance in membrane separation processes can be optimized through a good understanding of the mass transfer phenomenon and the transport resistances involved in the operation. Thus, this chapter focused on the discussions of mass transfer mechanisms and models in membrane separation based on several types of driving forces. This includes the pressure from a mechanical operation, partial pressure, osmotic pressure, concentration, and also thermal gradients. The chapter elaborates on the transport resistances in membrane resulting from membrane fouling and concentration polarization. The author hopes that readers, especially engineers and technical operators, gain a deep understanding and comprehensive knowledge regarding the theories and are able to utilize the knowledge to optimize the membrane operation.

Fundamentals of Membranes and Membrane Processes

Research into the wide possibilities of membrane-based applications is an interesting subject for the modern study of membrane science and technology. Membrane processes have been established as viable and recognized separation techniques in water and wastewater treatment processes. Membranes can be prepared into many forms, each with its intrinsic properties which ultimately determine its suitability for specific applications as well as the overall performance of the process. Thus, this chapter highlights the fundamental concepts of membranes and membrane processes. The critical parameters in membrane processes, and membranes' structural characteristics and parameters are reviewed.

Membranes and Microalgae in Wastewater Treatment

The application of microalgae-based wastewater treatment was first introduced in the 1940s to treat municipal wastewater. Microalgae have been studied for its various potentials such as for nutrients removal, carbon dioxide (CO2) removal, biofuel production from biomass, etc. This chapter focuses on the potential of microalgae membrane bioreactors for wastewater treatment, microalgae cultivation, and harvesting. Furthermore, the selection of microalgae species is covered by comparison of nitrogen, phosphorus, COD, and BOD removal from various studies. Microalgae membrane bioreactors combine the biological treatment of microalgae with the conventional membrane bioreactor. Still, membrane fouling phenomenon is a challenge in microalgae membrane technology. Thus, several other technologies of immobilized microalgae are introduced which can potentially reduce the membrane fouling occurrence and concurrently remove the need for microalgae harvesting process.

Membrane Processes in Water and Wastewater Treatment

Membrane technologies play a very important role in water and wastewater treatments. These membrane processes provide key advantages over the conventional processes, such as lower energy requirement, lower footprint, easier to operate, and more effective contaminants removal. This chapter introduces different membrane processes: (1) pressure-driven membrane processes which are the most widely used in water and wastewater treatments, and (2) several advanced membrane processes. These processes perform physical or physicochemical separations. Most of the separations occur between liquid-liquid phases, but liquid-gas and gas-gas separation phases are also performed in the latest membrane development. The contemporary membrane bioreactor is the heart of membrane technologies that are used in various applications. However, fouling is a common phenomenon that reduces the efficiency of the membrane operation. Thus, the concept of critical flux and introduction of some control and preventive mechanism could prevent or reduce the fouling in membrane bioreactors.

Clean Water Production for Isolated Areas

The provision of clean water is a global concern that must be critically addressed by all government bodies. However, lack of attention to this matter presents difficulties to many rural regions, especially in the developing countries. Most rural regions around the world experience lack of clean water due to various factors such as shortage of water resources and lack of water treatment facilities due to geographical constraint and scatter of population. Thus, small-scale water treatment system is an attractive technology for clean water production in isolated areas as it only requires a small footprint and it is more cost-effective than conventional water treatment plants. This chapter focuses on the small-scale water treatment systems for each of surface water, groundwater, rainwater, and brackish water resources. Considerations are taken based on the type of water resources and geographical conditions of the rural areas which include flat grounds, hills, and island areas. Besides, rainwater harvesting and treatment is reviewed for individual house application.

Membrane Characterizations

Membrane characterization is a critical necessity throughout the membrane's lifecycle. It mainly provides the connection between the fabrication and performance of the membrane. At the fabrication stage, membrane characterization allows us to study the membrane's characteristics in terms of its structure, morphology, chemical and physical properties, transport properties, etc. Membrane operation allows the determination of whether membrane cleaning is required or replacement is necessary. Finally, characterization at the end stage of membrane usability provides the causes of membrane failure which are significant data for future references. In that essence, this chapter discusses several methods that are used in membrane characterization processes, which are mainly categorized into the transport/flow, electron microscopy, scattering, and spectroscopy characterization methods.

Palm Oil Mill Wastewater and Treatment

Palm oil is an essential agricultural commodity in Malaysia, as Malaysia is one of the largest producers and exporters globally. The processes of palm oil extraction and purification generate a large amount of wastewater known as palm oil mill effluent (POME). Currently, most treatment processes are carried out using a conventional ponding system which is outdated as it requires large land areas and long retention time. Discharge of poorly treated POME directly to the surroundings leads harms the environment, as it contains high contents of oil and BOD. Therefore, this chapter discusses the treatment method of POME from a newer perspective of membrane technology integrated with biological treatment. Various methods such as clarification system with nanofibre unit, cooling system, activated sludge system, and anaerobic membrane bioreactor, are reviewed on their principles of operation.

Sewage Management and Treatment

Accumulation of sewage is a global issue that occurs primarily due to the rising rate of population growth. Without proper treatment and management, uncontrolled sewage generation threatens human health, environment, and society. This chapter briefly introduces sewage management and regulations. The conventional method of sewage and sludge treatment consists of pre-treatment, primary, secondary, and tertiary treatments before the sewage is safe to be discharged. Several sewage treatment technologies are introduced, namely the septic tank, intermittent decanted extended aeration, activated sludge system, membrane sewage treatment system, and finally the anaerobic digester.