Water supply and sewerage of the "Stoun" microdistrict in Konopnytsia (818 inhabitants), Lvivskyi Distr., Lviv Region
Students Name: Diachyshyn Nataliia Myronivna
Qualification Level: magister
Speciality: Water Supply and Sewerage System
Institute: Institute of Civil Engineering and Building Systems
Mode of Study: full
Academic Year: 2024-2025 н.р.
Language of Defence: англійська
Abstract: In the master’s qualification work, water supply and drainage networks are designed for the "Stone" residential area in the village of Konopnytsia, Lviv district, Lviv region, modular local treatment facilities for biological treatment of domestic wastewater of the BioTech system type with a capacity of 300 m3/day are designed for domestic wastewater treatment. Taking into account the significant length of gravity sewer networks and the complex relief of the development site, a sewage pumping station is designed to lift wastewater. The sewage pumping station is a sealed underground tank in plan 3000 mm with a sanitary zone of 15 m, where two submersible fecal pumps with cutting mechanisms (1 working, 1 backup) of the Wilo Rexa PRO (q=35.0 m?/h, H=10.0 m). The volume of the receiving chamber of the sewage pumping station tank is taken for 10 minutes of pump operation and is 7.5 m3. Sewerage networks are designed from polyethylene pressureless and pressure pipes. The concentration of pollutants in domestic wastewater discharged for treatment is 325 mg/l, BODtotal – 375 mg/l, COD – 480 mg/l, NH4 – 20 mg/l. According to the equipment passport data, wastewater undergoes complete biological treatment with the content of suspended solids brought to 5 mg/l; BODtotal to 5 mg/l; ammonium nitrogen to 1 mg/l; dissolved oxygen to 3.5 mg/l. After treatment and disinfection, wastewater is discharged into the reclamation canal of the settlement, which is located next to the construction site of the treatment facilities. The work provides a scheme for complete biological treatment of wastewater and disinfection of wastewater to enable water discharge into a water body. On the above equipment, wastewater treatment takes place in several stages: - Mechanical wastewater treatment, which takes place in the first chamber-well, where a basket is installed to catch coarse debris with 2.2 mm slots.; - Mechanically purified water enters the aerator, where preliminary aeration takes place to enrich the wastewater with oxygen, after which the wastewater is dosed by aerolifts and pumping equipment into aeration tank No. 1; - The next chamber of the aeration tank with bioloading. Thanks to the biofilter with attached aerobic microflora, the bulk of the contaminants are cleaned, in the presence of bacteria, nitrification occurs when air is supplied - wastewater is cleaned of pollutants, including organic substances, nitrogen and phosphorus compounds, under aerobic conditions using activated sludge, where microbubble aeration occurs and pumping equipment doses the clarified wastewater into the next chamber; - Then, after passing through the second zone of the aeration tank, the water is further purified by the 2nd stage of the aeration tank; - Wastewater enters the secondary settling tank, where it is divided into purified water and sludge. In this case, the activated sludge is sent for recycling, and the excess sludge is sent to a separate storage and stabilization compartment; - After the activated sludge stabilizer, the sludge is diverted for recycling to the first aeration tank; - From the sludge stabilizer chamber, the excess sludge enters the screw dehydrator to dry the sludge and drain it into a separate container for disposal; - Water after the secondary settling tank enters a contact well with a UV lamp to disinfect water from viruses; - Biologically purified water exits the system by gravity and is diverted to the discharge point. The object of the study is rainwater. The subject of the study is quality indicators. The purpose of the study is to analyze the quality of rainwater as an alternative source of domestic water supply. Often, in pursuit of health, people find various sources of "living" and "healthy" water, but it turns out that the water from them is even more dangerous than, for example, tap water. In order to understand the composition of rainwater, you need to understand where it comes from. When sunlight hits the water surface, part of the water evaporates and disperses in the atmosphere. When warm air masses come into contact with cold ones, rain clouds are formed. They consist of ice crystals and supercooled droplets. When the mass becomes critical, the crystals connect with each other, sinking lower, melt and fall to the ground as rain, forming stormwater, which then flows into the oceans, reservoirs and groundwater through the surface of the earth. So it can be assumed that rainwater is absolutely clean and safe for human health. But the atmosphere, that is, the air around, depending on the region, can contain a huge amount of various pollutants. Water, accordingly, is able to absorb almost everything. According to the table attached to the law on the protection of atmospheric air of settlements, there can be 509 different types of pollutants in the atmosphere of cities. The main ones are: nitrogen and sulfur oxides, ammonia, vapors of ldehydes and phenols, including formaldehyde, as well as soot, dust containing heavy metals and their compounds. Sulfur and nitrogen oxides, which are perhaps the main air pollutants and are present wherever there are cars, thermal power plants and heavy industries. They are capable of forming sulfuric and nitric acids in the process of reaction with water. Of course, drinking such water will not be useful, it is not rational to use it even for irrigation. The next common pollutant is small solid particles - dust, ash, soot, inorganic and organic compounds of lead (it is this that is released when using leaded gasoline), mercury, etc. These components are mainly only partially soluble in water, but after being introduced into the soil and water bodies by rain, they successfully enter the human food chain. Another consequence of dust pollution of rainwater is that bacteria perfectly attach to solid particles. Their presence in the air will not be dangerous, but after accumulating in water, they are capable of forming very viable colonies. It turns out that one liter of rainwater is capable of absorbing pollution from 300 m? of air. Ammonia, phenols, benzopyrene - all this is also in the air of large cities and will definitely be contained in stormwater. So, there are few full-fledged chemical analyses, but they say that such water is not worth drinking. We can conclude that rainwater, distilled on the way to the cloud, is no longer the same when it reaches the ground, so it is not worth evaluating it as a safe source of water supply without proper purification. Before implementation, each rainwater purification technology must be evaluated, tested and confirmed. Verification monitoring should be based on three microbiological indicators (E. coli, L. pneumophila and P. aeruginosa with a cut-off value of less than 3 CFU/MPN/100 ml) and physicochemical indicators (pH, turbidity, total organic carbon, odor, free chlorine, temperature, etc.). Key words: rainwater, treatment, rainwater, quality indicators. References. 1. ДБН В.2.5-64:2012. Внутрішній водопровід та каналізація. Частина І. Проектування. Частина ІІ. Будівництво. 2. ДБН В.2.5-74:2013. Водопостачання. Зовнішні мережі та споруди. Основні положення проектування. 3. ДБН В.2.5-75:2013. Каналізація. Зовнішні мережі та споруди. Основні положення проектування. 4. Water Code of Ukraine. 5. Rules for the protection of surface waters from pollution by return waters. 6. ДСТУ 7525:2014 Вода питна. Вимоги та методи контролювання якості. 7. Chidamba L, Korsten L. Relative proportions of E. coli and Enterococcus spp. may be a good indicator of potential health risks associated with the use of roof harvested rainwater stored in tanks. Environ Monit Assess. 2018;190(3):177. 8. Hamilton K, Reyneke B, Waso M, Clements T, Ndlovu T, Khan W, et al. A global review of the microbiological quality and potential health risks associated with roofharvested rainwater tanks. Npj Clean Water. 2019;2:7.