Application of UV-Based Advanced Oxidation Processes in Water and Wastewater Treatment

The presence of hazardous micropollutants in water and wastewater is one of the main concerns in water management system. This micropollutant exists in a low concentration, but there are possible hazards to humans and organisms living in the water. Moreover, its character that is recalcitrant to microbiological degradation makes it difficult to deal with. Advanced oxidation processes (AOPs) are efficient methods to remove low concentration micropollutants. AOPs are a set of processes consisting the production of very reactive oxygen species which able to destroy a wide range of organic compounds. The main principal mechanism in UV-based radical AOP treatment processes is the use ultraviolet light to initiate generation of hydroxyl radicals used to destroy persistent organic pollutants. Therefore, this chapter presents an overview on the principle of radical oxidant species generation and degradation mechanism by various type of UV based AOP in treating contaminants present in water and wastewater. The current application and possible improvement of the technology is also presented in this chapter.

Ozonation With Catalyst in Landfill Leachate Treatment

Landfill leachate is a hazardous pollutant generated from a landfill site. Discharge of landfill leachate has caused a major contamination to the environment and detrimental to human health. This chapter introduces an alternative method to treat recalcitrant pollutant in leachate by using ozonation with catalyst. The production of hydroxyl radical in ozonation was not enough to oxidize complex molecular structure in the leachate. Theoretically, the addition of catalyst enhances the capacity of radical and accelerates the chemical reaction. The effectiveness of ozonation with Fenton (O3/Fenton), hydrogen peroxide (O3/H2O2), and zirconium tetrachloride (O3/ZrCl4) in removing pollutant such as chemical oxygen demand (COD), color, and improvement of biodegradability by using this process were also discussed in this chapter. Comparison in term of treatment cost and benefits of the application of chemical as catalyst are briefly elaborated at the end of this chapter.

Application of Persulfate in Textile Wastewater Treatment

As textile and dyeing industries increase, pollution due to effluent discharges from the same industries also increase and become of great concern to a healthy environment. In an attempt to understand the generation and treatment of textile wastewater, this chapter discusses the processes from which textiles are made, items of importance that are used in the production process which may account for the characteristics of the wastewater and persulfate, applied in the treatment of textile wastewater. Although these wastewaters are generally characterized by color, fluctuating pH, heat, salts, suspended solids (SS), the presence of metal ions, biological oxidation demand (BOD), and chemical oxygen demand (COD), color is the most obvious. The presence of color in the effluents from textile dyeing and finishing is due to the inefficient dyeing processes, resulting in unfixed forms of the dyestuff. To achieve the primary objective of obtaining a clean environment, there is a need for continuous monitoring of textile wastewater discharges, of which major concern is color.

Advanced Oxidation Processes (AOPs) in Landfill Leachate Treatment

Sanitary landfilling is the most acceptable method to eliminate solid urban wastes. However, it is known that sanitary landfill generates large amount of heavily polluted leachate. High concentrations of recalcitrant organics make its degradation more complicated and high concentration of organic material can be toxic and reduce bioremediation process. Landfill leachate treatment by advanced oxidation processes (AOPs) have been intensively studied with high successful rate for removing refractory pollutants (biological degradation) from leachate. Fenton reaction which is one basic AOPs is based on the addition of hydrogen peroxide to the leachate in the presence of ferrous salt as a catalyst. Because of that, many improvement and development of new Fenton-based methods have been reported in the literature. This review discussed the application of Fenton and related processes in terms of wide application in landfill leachate treatment. The effects of various operating parameters and their optimum ranges for organics contaminant removed were also discussed.

Groundwater Treatment via Ozonation

Groundwater is the source of drinking water that needs to be maintained from pollution. Groundwater pollution is a major problem caused by human activities that are invaluable to human health. When high levels of organic and inorganic substances do not exceed the standard of drinking water, various studies have been made by researchers to overcome the problem. Various alternatives such as in-situ and ex-situ treatment have been carried out to eliminate pollutants from groundwater. Among the treatment, ozone becomes a major alternative because of its effectiveness in treating raw water. Ozone treatment has several advantages such as disinfectants, oxidize of organic and inorganic pollutant, and remove taste and color from groundwater. The performance of ozonation process becomes better when combined with other treatments. Therefore, application of ozone can replace chlorine because of its good potential to improve quality of groundwater effluent and comply drinking water standard adopted by World Health Organization.

Photocatalysis (TiO2/Solar) in Water and Wastewater Treatment

Advanced oxidation processes (AOPs) have gained growing importance for the removal of organic pollutants from water. Heterogeneous photocatalysis has been rapidly expanding for water treatment. This approach has economic and sustainability advantages compared with other processes. The main advantage of this process is its capability to gain complete oxidation or mineralization of organic contaminants at conditions of near ambient temperature and pressure. This chapter aims to review the mechanism involved in this process, characteristics of semiconductor photocatalyst, difference between suspended and immobilized photocatalyst system, comparison between the use of natural sunlight and commercial lamp, also the reactor involved. Potential advantages and limitations, as well as the application of photocatalysis in water and wastewater are also discussed.

Concentrated Landfill Leachate Treatment by Electro-Ozonation

Municipal solid waste has continued to be a major problem in many nations of the world. The primary methods of treating landfill leachate include physical-chemical and biological treatment processes. Pressure-driven membrane processes, such as microfiltration, ultrafiltration, nanofiltration, and reverse osmosis (RO), are among the utmost promising and capable ways for treating landfill leachate. The concentrated leachate created from pressure-driven membrane processes typically represents 13%–30% of total incoming landfill leachate. Concentrated leachate is a dark brown solution with high levels of pollutants. Treating concentrated leachate is extremely difficult, and thus, a combined treatment system is suggested. In the present study, concentrated landfill leachate was treated using a combined treatment technique that included electro-ozonation. The removal efficacies of chemical oxygen demand (COD), color, and nickel were monitored at original pH (7.3) as well as current and voltage of 4 A and 9 V, respectively.

Introduction to Water and Wastewater Treatment

This chapter elaborates the importance of water and wastewater treatment to human, environment, and world. It further discusses the water-borne diseases and other effects without implementation of water and wastewater treatment system. The principles of treatments are elaborated in detail as well. The standard parameters and value needed to be checked and compiled by the water and wastewater treatment system are not forgotten. This chapter explains the sources of water pollution such as from geography, ecology, and industry site. It also includes thoughtful discussion on causative factors behind water pollution, either human or other activity. The chapter views the importance of clean water in a variety of economic aspects. Without clean water what will happen to the world economy?

An Overview of Treatment of Antibiotics Using Advanced Oxidation Process

Antibiotics present in the environment are originated from pharmaceutical manufacturing processes or through wastes such as urine and feces. As antibiotics remain recalcitrant and persist in the treated water, consumption of treated water containing antibiotics raises a concern in the development of antibiotic resistance bacteria which would be later released to the environment. It might result in a vicious cycle which new antibiotics needs to be developed and dosage has to increase. Advanced oxidation processes (AOP) have been studied to effectively degrade antibiotics. During this process, hydroxyl radicals are formed to degrade organic compounds. Different APO are available in the literature such as photo-Fenton, Fenton, ozonation, sonolysis (UV), ultrasound combined with ozone, TiO2/direct photolysis, UV/H2O2, UV/ TiO2, UV/IGBT. To treat the high level of concentration of antibiotics, retention time of AOPs needs to be extended or/and OH• radicals need to be produced in a higher concentration for a complete mineralization.

Applications of Advanced Oxidation Processes in Palm Oil Mill Effluent Treatment

This chapter presents a review on limited studies that have been conducted using advanced oxidation processes (AOPs) in treating biologically treated palm oil mill effluent. Palm oil mill effluent is the byproducts of palm oil production that is normally treated using a series of biological processes. However, despite being treated for a long period of retention time, the effluent still possesses high concentration of organics, nutrients, and highly colored, and will pollute the environment if not treated further. Advanced oxidation processes that utilized hydroxyl radicals as their oxidizing agents have the potential of further treating the biologically treated POME. Fenton oxidation, photocatalysis, and cavitation are the main AOPs that have been studied in polishing the biologically treated POME. Depending on the experimental conditions, the removal of organics, in terms of COD, TOC, and color, could reach up to more than 90%. Nevertheless, each of this process has its own limitations and further studies are needed to overcome these limitations.