Water and Wastewater (original) (raw)
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Water and Waste Water Treatment
Multiple-barrier approach: Wastewater operations 15 Challenges facing water and wastewater operations Compliance with new, changing, and existing regulations Sustaining infrastructure Sustaining energy Privatization or reengineering Benchmarking Benchmarking: The process 34 Maintaining a viable workforce Upgrading security Consequences of 9/11
Book Chapter, 2011
Waste Water-Evaluation and Management 380 Today there have been great advances to make portable water from wastewater. In recent times, regardless of the capacity of the receiving stream, a minimum treatment level is required before discharge permits are granted (Peavy, Rowe and Tchobanoglous, 1985). Also presently, the focus is shifting from centralized systems to more sustainable decentralized wastewater treatment (DEWATS) especially for developing countries like Ghana where wastewater infrastructure is poor and conventional methods are difficult to manage (Adu-Ahyia and Anku, 2010). 1.2 Objectives of wastewater treatment Wastewater treatment is very necessary for the above-mentioned reasons. It is more vital for the: Reduction of biodegradable organic substances in the environment: organic substances such as carbon, nitrogen, phosphorus, sulphur in organic matter needs to be broken down by oxidation into gases which is either released or remains in solution. Reduction of nutrient concentration in the environment: nutrients such as nitrogen and phosphorous from wastewater in the environment enrich water bodies or render it eutrophic leading to the growth of algae and other aquatic plants. These plants deplete oxygen in water bodies and this hampers aquatic life. Elimination of pathogens: organisms that cause disease in plants, animals and humans are called pathogens. They are also known as microorganisms because they are very small to be seen with the naked eye. Examples of microorganisms include bacteria (e.g. vibro cholerae), viruses (e.g. enterovirus, hepatits A & E virus), fungi (e.g. candida albicans), protozoa (e.g entamoeba hystolitica, giardia lamblia) and helminthes (e.g. schistosoma mansoni, asaris lumbricoides). These microorganisms are excreted in large quantities in faeces of infected animals and humans (Awuah and Amankwaa-Kuffuor, 2002). Recycling and Reuse of water: Water is a scarce and finite resource which is often taken for granted. In the last half of the 20th century, population has increased resulting in pressure on the already scarce water resources. Urbanization has also changed the agrarian nature of many areas. Population increase means more food has to be cultivated for the growing population and agriculture as we know is by far the largest user of available water which means that economic growth is placing new demands on available water supplies. The temporal and spatial distribution of water is also a major challenge with groundwater resources being overdrawn (National Academy, 2005). It is for these reasons that recycling and reuse is crucial for sustainability. 1.3 Types of wastewater Wastewater can be described as in the figure below. Wastewater Stormwater Runoff Blackwater Grey water Industrial Domestic Urine Faeces Kitchen Bathroom Laundry Fig. 1. Types of Wastewater www.intechopen.com Wastewater Management 381 2. Definition of concepts and terminology Stormwater Runoff is water from streets, open yard etc after a rainfall event which run through drains or sewers. Industrial wastewater is liquid waste from industrial establishments such as factories, production units etc. Domestic wastewater also known as municipal wastewater is basically wastewater from residences (homes), business buildings (e.g. hotels) and institutions (e.g. university). It can be categorized into greywater and blackwater. Greywater also known as sullage is liquid waste from washrooms, laundries, kitchens which does not contain human or animal excreta. Blackwater is wastewater generated in toilets. Blackwater may also contain some flush water besides urine and faeces (excreta). Urine and faeces together is sometimes referred to as night soil. Sewage is the term used for blackwater if it ends up in a sewerage system. Septage is the term used for blackwater if it ends up in a septic tank. Sewerage system is the arrangement of pipes laid for conveying sewage. Influent is wastewater which is yet to enter in a wastewater treatment plant or liquid waste that is yet to undergo a unit process or operation. Effluent is the liquid stream which is discharged from a wastewater treatment plant or discharge from a unit process or operation. Sludge is the semi-solid slurry from a wastewater treatment plant. On-Site System: this is wastewater disposal method which takes place at the point of waste production like within individual houses without transportation. On-site methods include dry methods (pit latrines, composting toilets), water saving methods (pourflush latrine and aqua privy with soakage pits and methods with high water rise (flush toilet with septic tanks and soakage pit, which are not emptied). Off-Site System: in this system, wastewater is transported to a place either than the point of production. Off-site methods are bucket latrines, pour-flush toilets with vault and tanker removal and conventional sewerage system. Conventional sewerage systems can be combined sewers (where wastewater is carried with storm water) or separated sewers. Septic Tank is an on-site system designed to hold blackwater for sufficiently long period to allow sedimentation. It is usually a water tight single storey tank. Faecal sludge refers to all sludge collected and transported from on-site sanitation systems by vacuum trucks for disposal or treatment. Unit Operation: this involves removal of contaminants by physical forces. Unit Process: this involves biological and/or chemical removal of contaminants. Wastewater Treatment Plant is a plant with a series of designed unit operations and processes that aims at reducing certain constituents of wastewater to acceptable levels. How to reference In order to correctly reference this scholarly work, feel free to copy and paste the following:
Environmental Science & Technology, 1994
The essential tasks and capabilities that were identified through this process are called the core competencies. The following pages list the core competencies for water treatment operators. The core competencies are clustered into the following job duties:
National Alliance for Water Innovation (NAWI) Municipal Sector Technology Roadmap 2021
2021
2.4. Nontraditional Waters of Interest 2.4.1. Sources of Nontraditional Waters NAWI has identified eight nontraditional water supplies of interest for further study (Figure 1): Seawater and Ocean Water Water from the ocean or from bodies strongly influenced by ocean water, including bays and estuaries, with a typical total dissolved solids (TDS) between 30,000 and 35,000 milligrams per liter (mg/L). Brackish Groundwater Water pumped from brackish aquifers with particular focus on inland areas where brine disposal is limiting. Brackish water generally is defined as water with 1,000 to 10,000 mg/L TDS Industrial Wastewater Water from various industrial processes that can be treated for reused Municipal Wastewater Wastewater treated for reuse through municipal resource recovery treatment plants utilizing advanced treatment processes or decentralized treatment systems Agricultural Wastewater Wastewater from tile drainage, tailwater, and other water produced on irrigated croplands as well as wastewater generated during livestock management that can be treated for reuse or disposal to the environment Mining Wastewater Wastewater from mining operations that can be reused or prepared for disposal Produced Water Water used for or produced by oil and gas exploration activities (including fracking) that can be reused or prepared for disposal Power and Cooling Wastewater Water used for cooling or as a byproduct of treatment (e.g., flue gas desulfurization) that can be reused or prepared for disposal NAWI identified these broad "PRIMA" sectors because they are major users of water with opportunities for reuse. Figure 2 expands on the industries included in NAWI's PRIMA broad end-use sectors. These areas are not meant to be exhaustive, as nearly all industries and sectors rely on water in one way or another. Power Water used in the electricity sector, especially for thermoelectric cooling Resource Extraction Water used to extract resources, including mining and oil and gas exploration and production Industrial Water used in industrial and manufacturing activities not included elsewhere, including but not limited to petrochemical refining, food and beverage processing, metallurgy, and commercial and institutional building cooling Municipal Water used by public water systems, which include entities that are both publicly and privately owned, to supply customers in their service area Agriculture Water used in the agricultural sector, especially for irrigation and food production Nature Urban Water Use Wastewater Treatment Advanced* Treatment Disinfection
National Alliance for Water Innovation (NAWI) Master Technology Roadmap
2021
I n t r o d u c t I o n Clean water is critical to ensure good health, strong communities, vibrant ecosystems, and a functional economy for manufacturing, farming, tourism, recreation, energy production, and other sectors' needs. Research to improve desalination technologies can make nontraditional sources of water (i.e., brackish water; seawater; produced and extracted water; and power sector, industrial, municipal, and agricultural wastewaters) a cost-effective alternative. These nontraditional sources can then be applied to a variety of beneficial end uses, such as drinking water, industrial process water, and irrigation, expanding the circular water economy by reusing water supplies and valorizing constituents we currently consider to be waste. As an added benefit, these water supplies could contain valuable constituents that could be reclaimed to further a circular economy. I n t r o d u c t I o n 1.2. Pipe-Parity and Baseline Definitions A core part of NAWI's vision of a circular water economy is reducing the cost of treating nontraditional source waters to the same range as the portfolio of accessing new traditional water sources, essentially achieving pipe-parity. The costs considered are not just economic but include consideration of energy consumption, system reliability, water recovery, and other qualitative factors that affect the selection of a new water source. To effectively assess R&D opportunities, pipeparity metrics are utilized; they encompass a variety of information that is useful to decision makers regarding investments related to different source water types. Pipe-parity is defined as technological and non-technological solutions and capabilities that make marginal water sources viable for end-use applications. Like the concept of grid parity (where an alternative energy source generates power at a levelized cost of electricity [LCOE] that is less than or equal to the price of power from the electricity grid), a nontraditional water source achieves pipe-parity when a decision maker chooses it as their best option for extending its water supply. Specific pipe-parity metrics of relevance can include: Cost Cost metrics can include levelized costs of water treatment as well as individual cost components, such as capital or operational and maintenance (O&M) costs. Energy Performance Energy performance metrics can include the total energy requirements of the water treatment process, the type of energy required (e.g., thermal vs. electricity), embedded energy in chemicals and materials, and the degree to which alternative energy resources are utilized. Water Treatment Performance Water treatment performance metrics can include the percent removal of various constituents of concern and the percent recovery of water from the treatment train. Human Health and Environment Externalities Externality metrics can include air emissions, greenhouse gas emissions, waste streams, societal and health impacts, and land-use impacts. Process Adaptability Process adaptability metrics can include the ability to incorporate variable input water qualities, incorporate variable input water quantity flows, produce variable output water quality, and operate flexibly in response to variable energy inputs. I n t r o d u c t I o n Seawater and Ocean Water Water from the ocean or from bodies strongly influenced by ocean water, including bays and estuaries, with a typical total dissolved solids (TDS) between 30,000 and 35,000 milligrams per liter (mg/L). Brackish Groundwater Water pumped from brackish aquifers, with particular focus on inland areas where brine disposal is limiting. Brackish water generally is defined as water with 1-10 grams per liter (g/L) of total dissolved solids (TDS). Industrial Wastewater Water from various industrial processes that can be treated for reused Municipal Wastewater Wastewater treated for reuse through municipal resource recovery treatment plants utilizing advanced treatment processes or decentralized treatment systems Agricultural Wastewater Wastewater from tile drainage, tailwater, and other water produced on irrigated croplands, as well as wastewater generated during livestock management, that can be treated for reuse or disposal Mining Wastewater Wastewater from mining operations that can be reused or prepared for disposal Produced Water Water used for or produced by oil and gas exploration activities (including fracking) that can be reused or prepared for disposal Power and Cooling Wastewater Water used for cooling or as a byproduct of treatment (e.g., flue gas desulfurization) that can be reused or prepared for disposal These nontraditional water sources range widely in TDS (100 milligrams per liter [mg/L]-800,000 mg/L total) as well as the type and concentrations of contaminants (e.g., nutrients, hydrocarbons, organic compounds, metals). These different water supplies require varying degrees of treatment to reach reusable quality.
ON-SITE WASTEWATER: A CRITICAL PART OF A SUSTAINABLE & INTEGRATED WATER INFRASTRUCTURE
Water plays such a vital role in everyday life that we cannot afford to ignore aging infrastructure, changing sources, status quo operations, complex sociological issues, and their interactions. On-site wastewater systems have been and will remain an important part of our nation's water infrastructure, but they have yet to be considered as an integral part of the " main stream " centralized water and sewer infrastructure. On-site wastewater systems, when responsibly managed, offer a sustainable alternative to centralized systems and allow for cost-effective water reuse compared to centralized systems. Recent drought and flood conditions across the country have increased awareness to the risks and limitations of a centralized water infrastructure and created interest in developing alternative options. A team of researchers and engineers at Texas A&M AgriLife asked the question-what constitutes a " sustainable " water infrastructure? Answering this question is the goal of a long-term research project entitled the Sustainable and integrated Water infrastructure (SiWi™) program. This paper gives details on SiWi, outlines the role on-site wastewater systems play in SiWi, and presents policy options for making current and future on-site wastewater systems an integral part of SiWi. The paper also discusses software under development that will assist in evaluation of infrastructure alternatives (e.g., centralized versus distributed, single use versus reuse of available water, use of rain/storm water harvesting and desalination to supplement surface and groundwater sources, etc.) allowing stakeholders to analyze large amounts of data and make critical multi-objective decisions. The resulting " SiWi index " of a proposed water infrastructure project will provide stakeholders a better understanding of their options and lead to informed decision making. Finally, the paper reports on an ambitious project to develop the first SiWi demonstration on the new Texas A&M RELLIS Campus located in Bryan, Texas.