This paper reviews the literature on noise monitoring, noise mapping and noise modeling studies carried out in different countries by many researchers. The article reveals the current status of the noise-related studies and noise mapping studies. It was discovered that 90% of the noise monitoring studies were focused on the traffic noise, while the remaining 10% focused on the residential, commercial and industrial areas. Sometimes, there may be a necessity to analyze the sound pressure levels all over the place, or around a particular piece of land and machinery of industry. Researchers have used the noise monitoring data for the development of 2D and 3D noise maps which gives a clear picture of the noise level around the source of noise in X, Y, and Z direction. For taking a decision regarding the noise level for any development project, predicting the noise level is always necessary. The traffic noise models are generally used for the purpose of prediction. Early models are based on constant vehicle speed, later some models predicted the noise level for interrupting the traffic flow. For instance, the Stop and Go model can be used for the prediction of the noise level in an interrupted flow. Four such models were reviewed and compared in this article.

BACKGROUNDThis study explores the feasibility of three different inoculum sources (anaerobic, aerobic, and anoxic sludge from conventional sewage treatment plants) together with the potential of biomass carrier for Anaerobic ammonium oxidation bacteria (anammox) cultivation. Fed‐batch reactors were operated with synthetic medium at different temperatures.RESULTSThe reactor inoculated with anaerobic sludge and biomass carrier showed close to stoichiometric nitrite to ammonia utilization (1.2:1) and the highest ammonia removal (12.2 mg NH4+·g VS−1·day−1), followed by the reactor inoculated with activated sludge without carrier (4.3 mg NH4+·g VS−1·day−1), which also showed close to stoichiometric nitrite to ammonia utilization. Anammox development was recorded by higher nitrogen removal, gradually increasing gas production rate, and the presence of Brocadiaceae anammox family bacteria. All batch reactors revealed significant phosphorus removal (>80%), which was attributed to the co‐existence of anammox bacteria (Brocadiaceae) with denitrifying polyphosphate accumulating organisms (flavobacterium sp.).CONCLUSIONThe results of this study revealed that anaerobic sludge and activated sludge from sewage treatment plants with biomass carriers for microbial immobilization were suitable for anammox bacteria enrichment. The co‐existence of anammox bacteria with denitrifying polyphosphate accumulating microorganisms reveals new possibilities for simultaneous nitrogen and phosphate removal. © 2020 Society of Chemical Industry (SCI)

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Noise pollution has been rising as a critical issue in recent days particularly for the people living in urban areas. This study has been conducted to find out the effects of traffic induced noise on nearby residential building through 3D noise mapping with and without noise Barriers. Monitoring has been carried out at various densely populated preselected locations of Delhi, India. Thereafter, 3D noise mapping has been done using hourly average noise levels for the locations exposed with maximum noise. The developed 3D noise map shows the variation of noise level along X, Y and Z direction for all selected locations before and after installation of noise barriers. Moreover, the result also shows that exact assessment of noise impact is possible through 3D noise mapping, when a multistory building close to the source of noise is taken into consideration. This paper also elaborates the adequate height, distance and NRC value of noise barrier to reduce the effect of road traffic noise on nearby high rise building. Reduction pattern of noise level can easily be visualized and evaluated by using these maps. This type of study could support decision makers during adaptation of suitable remedial measures.

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