The removal of impurities from wastewater and its transformation into effluent, which can be recycled into the water cycle, are the two primary goals of the treatment process for wastewater. Treatment of wastewater, also known as sewage treatment, is the process of removing contaminants from wastewater, also known as sewage before it enters aquifers or natural sources of water such as rivers, ponds, marshes, and seas. Wastewater treatment is also known as sewage treatment. Any separation between safe drinking water and polluted water, given that pure water cannot be found in nature (that is, outside of chemical plants), is contingent on the nature and presence of impurities that are present in the water, in addition to the purpose for which the water will be put to use. A body of water is said to be contaminated, in a general sense, when it possesses a level of contaminants that renders it inappropriate for a particular use, such as swimming, fishing, or even just drinking.
The acceleration of the natural processes that occur during water purification is the primary goal of wastewater treatment. Waste management is broken down into its primary and secondary stages, both of which are described in detail in this article. During the initial stage of treatment, solids are permitted to settle out of the wastewater and are then removed. The biological methods used in the secondary step further purify the wastewater that has been collected. At last, an additional step takes place, which involves the disinfection of all the germs and microorganisms from the water.
The activated sludge plant at the laboratory sewage treatment facility also has upstream denitrification. Only the biological phases of treating wastewater are included in this process. The feedwater is first sent into the denitrification basin, where it remains for some time before moving on to the nitrification and secondary clarifying stages on its way to the drain water container. Internal recirculation is the process that guarantees the nitrate that is produced during the nitrification process is returned to the denitrification basin for recycling. Through the process of sludge recirculation, the active biomass removed during secondary clarification is returned to the denitrification basin.
Figure: Components of the lab sewage plant. A: Denitrification basin. B: Nitrification basin. C: Secondary clarifier. D: Feedwater container. E: Drain water container. F: Feedwater inlet. G: Internal recirculation. H: Sludge recirculation.
Nitrification is a biochemical process that transforms ammonia into nitrite and then nitrite to nitrate. Nitrate is an essential component in many biological processes. Denitrification is a process that converts nitrate back into nitrogen gas and can be used as an alternative treatment option in the event that certain regulations mandate the removal of the nitrate that was produced. Ammonia goes through a two-step process to become nitrate while undergoing nitrification, which takes place in the presence of oxygen (oxidation). First, Nitrosomonas convert ammonia (NH4+) into nitrite (NO2-), which is then subsequently converted to nitrate (NO3-) by Nitrobacter. Nitrite is a byproduct of the process. Pseudomonas and other heterotrophic bacteria are responsible for transforming nitrate (NO3-) into nitrogen (N2) during the denitrification process. This transformation takes during the absence of oxygen. To carry out this reduction process, organic material is employed as an electron donor.
Because it significantly impacts the concentrations of contaminants, particularly nutrients, the procedure of internal recirculation in treatment plants for wastewater is an essential component of the myriad of various biological activities that take place there. However, in sludge recirculating settling tanks, there is a zone called the clarification zone where the sludge is segregated from the clarified water. The aeration tank combines settled sewage with new sludge redistributing from the separating funnel. This process occurs continuously. Pumping air into a tank during the activated sludge process fosters the growth of microorganisms in the wastewater. This is referred to as aeration.
In labs, this work can be done by GC-MS. The analytes under study are separated using gas chromatography. A 15 to 100 m cylinder-filled capillary that is filled with inert gas, such as helium, makes up the chromatography column. Based on their chemical and physical characteristics, the evaporated analytes are introduced into the gas stream and move through the column. Very complicated analyte combinations can be broken down into their constituent parts in this manner. The separated compounds are identified and measured using mass spectrometry. The particles are fragmented in the mass spectrometer after being energized by electron impact ionization (EI). The chemical formula can be ascertained from the mass numbers of the mol peak and distinctive pieces and from the isotope pattern.
The majority of students taking biology classes are likely to be intimidated by the chemical sciences. Because analytical methods such as wastewater treatment and other chromatographic methods work at the intersection of distinct chemistry concepts, students of biology may become anxious at the mere presentation of these ideas.
The process of treating wastewater involves a wide variety of processes, including the separation of waste, treatment of waterways, and disinfection of the water. These procedures include a large number of chemical and biological processes, which can be quite challenging for pupils. A learner who has a limited understanding of chemistry could find it challenging to comprehend the function of each step.
As a chemistry-based topic, wastewater treatment can be difficult for students. In most cases, theoretical education with diagrams is used to cover the subject of chromatography as well as its various varieties and underlying principle. Using a flow chart may help pupils form an image in their heads of what is going on. However, students have a difficult time understanding the relevance of each phase in the process. The transition from one idea to the next is the most important factor that determines how difficult HPLC is to do. Before you can have that level of understanding in relation to the HPLC process, you need to have proper knowledge of a few different subjects first. It is vital to keep in perspective that the answer to this problem does not lie in determining the underlying mechanism of each subject, which once would be accomplished in a theoretical environment.
Here, the basic ideas of the solution, mixture, solvent, buffer, saturation, and concentration are developed. The ability to distinguish between these ideas is a must for students. Giving real-world examples will help with this. The properties that distinguish mixtures from solutions are briefly explained to the pupils. During a demonstration led by the teacher in the classroom, the students will have the opportunity to try and evaluate the physical characteristics of a few simple combinations and solutions. By doing so, the focus turned to chromatography and how we were able to separate combinations of various substances, bioactive molecules, and medications.
Providing facts is always the best way to increase students' interest in the topic. Here are some facts about the current topic:
Students want to learn the science with facts and proof. However, students want to see the process at the molecular level. Visual graphics make students more interested in the topic and make it easy for teachers to put words into action.
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To give more actual, personal experience, you can arrange a tour for your students if your schedule permits. Students can better understand the complexity and reality of the water and wastewater treatment system by participating in an activity that involves taking a tour of the water or wastewater treatment plant in their local community. In addition to that, it is an effective tool to raise awareness about potential career paths in the water industry for the years to come.
A helpful technique to teach the water cycle is using a virtual laboratory simulation. At Labster, we're committed to providing a fully interactive advanced diagnostic simulation laboratory that makes use of gamification components like narrative and score systems inside a captivating 3D setting. After touring a full-scale sewage facility, you'll work on a lab-scale water treatment facility with all the important stages. You and your students must use GC-MS to evaluate water samples during treatment.
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