Background and Objective:Due to the severe shortage of water resources in Iran, the application of wastewater effluent for agriculture has become inevitable. Disinfection is one of the crucial steps in water treatment. Common disinfection technologies such as chlorinati More
Background and Objective:Due to the severe shortage of water resources in Iran, the application of wastewater effluent for agriculture has become inevitable. Disinfection is one of the crucial steps in water treatment. Common disinfection technologies such as chlorination can effectively control microbial pathogens; however, undesirable disinfection byproducts (DBPs) are known to be toxic and carcinogenic. Therefore, the present study aimed to compare disinfection efficiency and regrowth control of microorganisms in urban wastewater effluent using gamma radiation and Ultra Violet treatments.
Method: The pre-disinfection effluent (before chlorination unit) was collected from south Tehran wastewater treatment plant, Tehran, Iran. The applied gamma radiation doses were 0.5, 1, 2, 4 and 6 kGy. UV disinfection systems were developed using a reactor with 1 L of liquid volume. The disinfection efficiency was evaluated based on the total colony count and total Coliform. For bacterial regrowth evaluation, the samples were incubated at 22 ◦C, 100rpm for three days in dark condition.
Findings: The number of total Coliform in all gamma ray doses was zero at the beginning of the experiment. The re-growth of total Coliform was observed at doses less than 2 kGy. In the treatment of ultraviolet radiation, at the beginning of the experiment, the lowest flow rate had the highest disinfection efficiency. However, after three days, the total Coliform population was higher than the allowed limit in all of the inflow rates.
Discussion and Conclusion: Gamma radiation can be applied as an effective alternative technique to UV treatment for disinfection processes without bacterial regrowth.
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Background and Objective: the aim of this survey was prevent the environmental pollutant, urban sewage sludge management and vermicompost production by beneficial usage of rice straw as an agricultural trash which burn in arable rice grounds.
Method: This study conduct More
Background and Objective: the aim of this survey was prevent the environmental pollutant, urban sewage sludge management and vermicompost production by beneficial usage of rice straw as an agricultural trash which burn in arable rice grounds.
Method: This study conduct to evaluate the nutrition matter consist of nitrogen, phosphorus, potash in (21±4˚c) temperature and pH (7±0.5) in urban sewage management, and provided the suitable vermicompost by pure dehydrate urban sewage mixed in rice straw as compared with rice straw and manure complex and pure dehydrate urban sewage (control; PDUS) containing E. feothida from three replication in 8 week. At the end of the test amount of nutrition matter was compared between treatments in (p<0.05) value.
Findings: Results shown, significant difference between treatment and reduced the amount of nitrogen, phosphorus, potash (p<0.05).So, the best level of nitrogen (1.21±022)% ,phosphorus(0.69±0.03)% and potash(0.07±0.01)% was determined in rice chaff and manure complex treatment. After this treatment, the PDUS mixed by rice chaff group had best point than control group innutrition matter except in amount of potassium. In potassium level after rice chaff and manure complex, control group was set in second station and the lower point was in dehydrate urban sewage mixed by rice chaff group.
Discussion and Conclusion: Followed our results, we can say that rice chaff was more effective to produce the urban sewage vermicompost. Also this is good agricultural manure cause to best nutritional value and it could be help us in urban sewage management.
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A large number of implementation projects regarding construction or rehabilitation of urban infrastructure systems are conducted in heavily populated areas; As a result, noise pollution generated from these operations is not limited to only a few people and will annoy c More
A large number of implementation projects regarding construction or rehabilitation of urban infrastructure systems are conducted in heavily populated areas; As a result, noise pollution generated from these operations is not limited to only a few people and will annoy community in large scale. Noise pollution may cause sleep disturbance, stress, loss of productivity in schools, offices, etc; This fact necessitates the need for considering social costs of noise pollution more carefully in urban areas. In this paper a model for evaluating monetary equivalent of noise pollution social costs in implementation of urban infrastructures has been proposed; General approach in this model is based on determining maximum allowable noise pollution in the affected area as well as determining intensity of the noise generated from operations in the adjacent receptors; Difference between the “existing” and “maximum allowable” noise levels is considered as part of the social costs of the project; Some methods for evaluating monetary equivalent of this social cost has been proposed in this paper; if the estimated value was large, some mitigation measures shall be taken to reduce the social costs of noise pollution; A number of these measures are also reviewed in the final part of the paper. In the end, suggested model has been utilized for quantification of noise pollution social costs in a small pilot area of Tehran where a sewage network has been implemented.
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