Why there is environmental science in civil engineering? We know that Civil Engineering work affect environment, why still study this?
The Environmental Science is the study of the use of water, air and land resources. The role of a civil engineer in environmental science is to manage the surface water and water quality standard also the groundwater quality in the bodies of water such as river near the cities. The water supply and the proper installation of sewerage in the houses, hospital needs to be also checked. It also applies on the solid waste management and the remediation of the contaminated sites for example the oil spillage in Pandacan, Manila when not proper dispose it can harm people living near the area of the factory. The leakage of the oil produces unwanted smell and later on causes people to have allergy and lung problems. The oil spillage can actually cause air pollution and land pollution. Another cause is that it can harm aquatic life and the water may be polluted. The activities of engineers also include the design, planning, construction and operation of the wastewater treatment facilities in the industries and municipalities. To define more the responsibility of a civil engineer involve on the construction and design of the infrastructure of the society which involved highway, bridges, transit systems, and dams, the sewage treatment systems and the municipal water. Analysis of the groundwater quality and surface water is needed to make sure it is safe to use for the households. Environmental science often study about the pollution of the air, water and soil and other environmental issues which related to civil engineering work. The soil design and remediation systems, the collection, transport, the disposal of the wastes and disposal of the wastewater and ways on how to reuse it are include in civil engineering practices. The remediation systems in the construction is the removal of the hazardous material on the site and or the contaminated wastes if ever it is a old factory of gasoline or fuel, the site conditions is another factor, if there is an existing building in the area and lastly nearby environment such as forest. The wastewater treatment has a great deal in civil engineers for they need to develop and recycling the one of the most natural resources in the earth which is the ware. In the wastewater treatment process it is complex and innovative as it need a lot of time rational thinking and planning to be sure on the proper uses of the natural surroundings. Moreover, the solid waste management is another job for the civil engineers it is the process of eliminating and minimizing of the wastes in reduce, reuse and recycle. The civil engineers need to think on how to make it possible. The transportation in land and air also take part in civil engineers such as the drainage and the water disposal in the road, the maintenance and repair. It is important to civil engineers to study environmental science to understand the process of involving the natural science in earth and the people surrounding it. The environmental science is also related to conserving the environment and our natural resources as population is growing the wastes are also increasing our role as civil engineers is to show to the people how to minimize the garbage and to introduce ways on conserving the water and to lessen the pollution on the earth.
The civil engineer plays a vital role in environmental science as they are responsible for conserving the natural resources of the earth and it involves the solid waste management, wastewater treatment, planning and designing the dams, transportation, analysis of the groundwater quality in the municipalities and industries.
1.0 Wastewater Engineering
The wastewater is a water that has been used in the industrial, agricultural crops and animals, feces of a human, chemicals such as the household products (shampoo, aerosol sprays, soap and others) it is also from the oils and food scraps. In household or community it includes the shower we used for bathing, the sink when cleaning dishes, the washing machine for washing and drying the clothes and the toilet and sink. The wastewater can have directly effect on the environment causes by the human activity it is made up of liquid discharged by the industrial factories, municipal, agriculture and commercial properties that can raise possibility of contaminants and concentrations in the water. One of the parts of the wastewater is the sewage which contains feces and urine. It usually disposed via pipe or sewer system and when not treated properly it causes harm to human. The sewage that is not treated properly contains bacteria, viruses and protozoa, water and solid waste such organic matter. It also includes greases from the oils and toxic and chemicals from the roofs and vehicles. These are some examples of waste from the wastewater that can cause health problems to humans, industrial wastes, domestic wastes and the feces; some are also from the agricultural fertilizer which comes from the animals. When the wastewater is released in the river and ocean some of the nutrients and polluted water are its contents and causes harm to the habitat and life of the aquatic resources. The sanitation is the best way to prevent the health problems. Sanitation is related onto sources of drinking clean water and proper disposal of excreta from human and sewage. Some of good habits to prevent human from directly contact with the feces is washing with hand soap. When the water is treated it reduces the risks of environmental pollution thus also improving one’s health. Wastewater is also important as it still water and does need to be treated to use again the aim in wastewater treatment is to have clean water supply and protect the water from bad substances. The wastewater engineering also known as the sanitation engineering are the ones designing, planning and analyzing the wastewater treatment process. The job for wastewater engineering is to make a dam that will protect the people and the community from flooding and to regularly check the water supply, to also site where to place or located the water treatment facility, how to maximize the conservation of water and especially on testing daily the water produce and used by the citizen to ensure that it is safe to drink. The wastewater has negative effect to the humans because of its characteristics it contains chemical oxygen, organic carbon, metals, the water has high acidity or alkaline and is probably from the trade or induced from the industrial factories, trace elements and priority pollutants; it also contains bacteria and microbial pollution. The physical characteristics of the wastewater are its foul odor, turbidity, its high temperature and some solid wastes. There are different processes in recycling the wastewater one of which is biological waste treatment plant in this step of treatment they use biological matter to break the solid waste and other bacteria, viruses and toxins in the wastewater making it safe and clean once again. The other method is physical wastewater treatment plant which uses reactions from the chemicals and physical processes for the sewage. The first method is usually used on the homes and communities while the other are used for the commercial and industrial properties. In reusing wastewater it can purify the water and reclaimed its use again.
2.0 Constituents in Wastewater
The wastewater constituents include the physical, chemical and biological characteristics that show the difference of the safe drinking water to the untreated water. There are important constituent of concern of the wastewater these are the suspended solids which is the indicator of the quality of water depending on its size it is likely to have high pollutant load when the size of the particle is smaller and thus it can removed through sedimentation or filtering the water to eliminate the suspended solids on the water and so to reclaimed almost as closed to drinking quality then followed by the disinfection of the water to ensure that the pathogens are already eliminated. The pathogens that are still linked in the suspended solid while filtering the water will be considered as ineffective and not safe to drink. The biodegradable organics is also part of the constituents as its basis is the biological oxygen demand (BOD) when there is a high demand in oxygen the support life from the earth will also lessen. Next is the pathogen which can spread diseases when not completely removed on the wastewater it is an organism that can enter your body and has different ways on entering for example directly contact with the feces or skin contact. It has different types such as the viruses, fungi, protozoa, parasites and bacteria all of which can be fatal when not treated fast. The nutrients in the wastewater when disposed on the aquatic environment may lead to damaging the habitat and aquatic life and when there is a lot of excess can cause land pollution. The priority pollutants which are consisted of the heavy metals and some organic pollutant chemicals that have high toxicity level are frequently found in the wastewater. The compounds are considered to be refractory organics when it is poorly biodegradable from biological oxygen demand to chemical oxygen demand. The heavy metals are compounds that are highly soluble to the water and when mix it became wastewater. When the heavy metals are disposed into the bodies of water the aquatic environment will be unbalanced and there is a high chance that the living organisms will absorbed it. It is proven in studies that the heavy metals affects the growth of the various species of fish making them have weak muscle tissues and preventing the fish to increase. The heavy metals have many disadvantages in the human, living organisms and environment. The dissolved inorganic substances are also constituents of the wastewater there are many chemical substances that are present in the ocean and are remarkably constant. It has various impacts on the world in the aquaculture the fishes may thrive but in land the growth of animals may decrease and lesser chance of survival. The ionic imbalance may be one of the cause as it leads to osmotic gradients and the gradients will eventually gone because of the flow of the water in its concentration. The depletion of the oxygen has biggest impact in the humanity because of the organic pollution and biodegrading processes but the water quality standard depends on the measurement of the aggregate organic compounds. The individual organic compounds has important role in the environment in accumulating the water on the surface of the planet. The biological characteristics of the wastewater are to determine the type of the contaminants present in the water. The treatment for the biological characteristic process is to set traps or filter the bacteria and the microorganisms in the water. The different identification of the toxicity components in the wastewater are filtration of the suspended solids where sedimentation is one of the process in removing it. Next is the filtration of the colloidal solids to remove the turbidity and color of the water. Then the ion exchange it is the process of disinfection and demineralization of the substances in water. The other processes are the molecular weight classification, biodegradability test, oxidant reduction, metal chelation, air stripping and lastly resin absorption and solvent extraction to reuse the wastewater again safely.
ANALYSIS AND SELECTION OF FLOWRATES AND CONSTITUENTS
The components of the wastewater flow may depend and based on the collection type of the system. The wastewater composed mostly of water with only 0.1 percent of the waste. The water that goes down from the toilet and drain is considered as wastewater. The basis of knowing the various components of the wastewater is the different ways in wastewater treatment process. One of the types of the wastewater flow is the domestic wastewater which came from the residential areas and it is sometimes called as sanitary sewage. It also means that the waste comes from the humans and not proper household operations such as bathing, preparation of food, washing dishes in the kitchen and laundry can cause problem and needed to be undergo the water treatment process. The industrial wastewater is also a type of collection system which comes from the combustion of the fossil fuels, atmospheric deposition and oil from the sailing ships. The industrial wastewater possibly dominates when the industrial water has been discharged. The solutions that have been dissolved from the substances and mixed with the water can also cause industrial wastewater. Moreover, there are different types of the infiltration or inflow rates, the infiltration is a process of water entering on soil in the earth’s surface in the case of the wastewater flow the water may enter on the defective pipe. One of the factor that affecting the infiltration is the precipitation which in the form of rain or in the of the other country the snow, the water can continuously flow in the streambeds and sometimes when there is no proper aquifer to hold the water it may overflow causing it to released on the pipes. The inflow is water that is dumped on the drainage or the sewer system without proper connections. The steady inflow is water that can found on the foundation drains and can be easily measured because the flow is steady. The direct inflow has direct connections on the sewer line system. For example the kitchen sinks and toilet when properly installed has directly connected to the sewerage system. The total inflow is the discharged of the direct inflow in any point of the system. The delay inflow is when the water is stuck on the drainage it will days to drain. The storm water is water which comes from the rain that is drain on the site, on the roof of the house and everything with it. The storm water is source that is valuable as it can be reuse and reduce the impacts on the environment. There are strategies on how to reduce the wastewater; one of the strategies is interior water use reduction. Interior water is the indoor use of water in a household for example you can turn off the faucets when not much of needed, reduce your time in showering and most important is to use every drop of the water and do not waste any of it. Another strategy is the reduction of the energy consumption in this way we can save more money and we can also help to balance the environmental impact. The last one are the flow of the usage in the devices and the appliances the examples is turning off the lights when not needed, if you have computer on your home unplug it when not in used as it consumes biggest energy. There are also different types of the collection system this are the sanitary, storm collection and combined systems. The sanitary collection system composed of the manhole, septic tanks, pipes and other it is mainly the collector of water on the residential and non residential houses. The storm collection system it helps on preventing a flood when raining if there are proper catch basin and drainage where the water flows. The combined collection system is a system that collects the water and wastewater from one pipe such as the industrial wastewater, domestic wastewater, and rainwater runoff.
INTRODUCTION TO PROCESS ANALYSIS AND SELECTION
There are different reactors for the treatment of the wastewater and the different processes are involved such as the physical unit, chemical and biological. These processes are carried to vessels and tanks which is known to be the reactors. The batch reactor is one of the reactors used to mix and blends the chemical completely to make sure there is no factor leaving. The batch reactor usually absorbs the heat while blending the contents and can be removed using cooling pipe to achieve the desired temperature. The batch reactor then poured the contents and if necessary purified. The complete-mix reactor it is the reactor where all the contents should be mixed thoroughly and uniform to have same composition. The plug-flow reactor only moves in one direction and no involved mixing usually more on the aeration systems. The complete-mix reactors in series it is the pattern of using continuously using the plug-flow and complete-mix reactor. The packed-bed reactors these can be operated in either up flow or down flow mode it has different type of materials such as rock, slag and others. The fluidized-bed reactor it used to carry many type of chemical reactions. It use gas and liquid to suspend the solids and this is called the process of fluidization. The applications of the reactors are based on the treatment process of the wastewater. One of the factors are the nature of the water that needs to be treated in the batch reactors it considered the color of the water from yellowish to black color, it can also considered the smell as water is known to be odorless and can be considered to be wastewater because of the odor, color and change in temperature. The other nature to be considered is the nature of the reactions if it is either homogenous or heterogeneous if both the contents are the same or immeasurable. The nature of kinetics governing the process of wastewater treatment it is because of the pH level content of the water. The process of performance requires in knowing the biological demand oxygen and suspended solids of the wastewater, to also know the local environment conditions if the water is extremely toxic and the drainage for the water treatment process. There are factors to be considered leading to non ideal flow in reactors one of which is the difference in temperature wastewater is high in temperature compare to the water that we usually drink. The wind-driven circulation patterns when there is a suspended solids content in water the circulation pattern does not match compare to usually one direction flow of the water. Inadequate mixing can result water quality problems led to short-circuiting it can cause suffocating fish and other aquatic life in the bodies of water. The axial dispersion in plug-flow reactors can cause problems because of the entrance and exit of water disturbances. It also refers to back mixing in axial direction. The mass transfer operations in wastewater treatment are also an important factor in the process of transferring the components and chemical gradient from one phase to another. The chemical reactions in the operation are also involved as it determines the distribution of the mass. The importance of the computations and is to possibly design and control the treatment process of the wastewater. The important factors in process selection are the process applicability, to know the range of the flow defining such as the steady, direct and inflow of the wastewater. The influent wastewater treatment refers to the basin and flow of the water in aquifers it also includes the pipe, reservoirs, and processes that involved in treating the wastewater. Other important factors are the Economics life analysis and the availability of the land.
PHYSICAL UNIT OPERATIONS
This process involved screening and there are different types of the screening. The coarse screen defines as the process of removing large solids suspended on the wastewater the others are the debris. The typical size of the coarse screen is 6 mm or larger. There different types of the coarse screens including hand cleaned, mechanical and manual. The hand cleaned coarse screen is bypass channel that includes small water pumping stations. There is a bar set on the bypass channel to make sure of the uniform approach of the distribution of the solids through the flow in the screen. The coarse screens also have trash rack to prevent the large debris on entering in the water treatment process. The mechanical coarse screen are composed of chain driven screens, reciprocating rake, catenary screen, and continuous belt screen they cleaned the screen and engages with the base screens to remove coarse solids found in the wastewater. The manually coarse screen is the simplest type of screening as it removes the large particle before entering in the waste treatment plant. The fine screens are process in removing that can create maintenance problems. The typical type of the fine screen is less than 6 mm. There is an also very fine screen which is placed on the coarse or fine screens in reducing solids that are suspended. The micro screens to remove the suspended solids on the secondary wastewater treatment. The screening characteristics and quantities for the coarse screen it can retained material about 12mm or greater while the fine screens can only retained less than 6 mm for example rags and razor blades. In coarse solid reduction have three types one of which is comminutors it is shape as cylinder and the wastewater freely pass through it. The process of cutting the large materials to reduce the size of the solids, the grinders it is the process of rotating the blades at high speed to pulverized the materials. The macarators used blades to cut all the solids and pumps through the pipeline to remove all the dirt from the water. The flow equalizations are the process of cleaning of the basin with the screening and grit removal. There are design considerations in the flow equalizations first is the location of the equalization facilities the location of the facilities must be based on the collection type of the system. The location facility must be based on the availability of the land and the characteristics and type of the waste water. The in-line and off-line equalization it is achieving the considerable damping of the loadings of the mass. The volume requirements for the equalization basin must also be considered to be using on inflow cumulative diagram. The mixing and flocculation process involved continuous rapid mixing in wastewater treatment it is used when both the substances are mixed together. Next is continuous mixing in wastewater treatment it is a process where the mixing used to trap the substances that are harmful it is need to increase the flocculation and some substances that are undesirable. The energy dissipation in mixing and flocculation it is needed to divide the particles from the chemical substances. The timescale in mixing is very important as it plays role of the balancing the rate of the rapid mixing of the liquid but for the slow mixing substances it is not that critical. The primary sedimentation is also a process of removing and breaking down of the suspended solids and some organic material floating on the wastewater. There are different type of tanks such as the rectangular tanks and circular tanks. The rectangular tank is a type of bridge collector and circular with the shape of radial.
Nice article... It's very informative🙂