Using long term simulations to understand heat transfer processes during steady flow conditions in combined sewers

This paper describes a new heat transfer parameterisation between wastewater and in-sewer air based on understanding the physical phenomena observed in free surface wastewater and in-sewer air. Long-term wastewater and in-sewer air temperature data were collected and studied to indicate the importance of considering the heat exchange with in-sewer air and the relevant seasonal changes. The new parameterisation was based on the physical flow condition variations. Accurate modelling of wastewater temperature in linked combined sewers is needed to assess the feasibility of in-sewer heat recovery. Historically, the heat transfer coefficient between wastewater and in-sewer air has been estimated using simple empirical relationships. The newly developed parameterisation was implemented and validated using independent long-term flow and temperature datasets. Predictive accuracy of wastewater temperatures was investigated using a Taylor diagram, where absolute errors and correlations between modelled and observed values were plotted for different site sizes and seasons. The newly developed coefficient improved wastewater temperature modelling accuracy, compared with the older empirical approaches, which resulted in predicting more potential for heat recovery from large sewer networks. For individual locations, the RMSE between observed and predicted temperatures ranged between 0.15 and 0.5 °C with an overall average of 0.27 °C. Previous studies showed higher RMSE ranges, e.g., between 0.12 and 7.8 °C, with overall averages of 0.35, 0.42 and 2 °C. The new coefficient has also provided stable values at various seasons and minimised the number of required model inputs

Using long term simulations to understand heat transfer processes during steady flow conditions in combined sewers

This is the final version. Available from MDPI via the DOI in this record. Data Availability Statement: Restrictions apply to the availability of these data.This paper describes a new heat transfer parameterisation between wastewater and in-sewer air based on understanding the physical phenomena observed in free surface wastewater and in-sewer air. Long-term wastewater and in-sewer air temperature data were collected and studied to indicate the importance of considering the heat exchange with in-sewer air and the relevant seasonal changes. The new parameterisation was based on the physical flow condition variations. Accurate modelling of wastewater temperature in linked combined sewers is needed to assess the feasibility of in-sewer heat recovery. Historically, the heat transfer coefficient between wastewater and in-sewer air has been estimated using simple empirical relationships. The newly developed parameterisation was implemented and validated using independent long-term flow and temperature datasets. Predictive accuracy of wastewater temperatures was investigated using a Taylor diagram, where absolute errors and correlations between modelled and observed values were plotted for different site sizes and seasons. The newly developed coefficient improved wastewater temperature modelling accuracy, compared with the older empirical approaches, which resulted in predicting more potential for heat recovery from large sewer networks. For individual locations, the RMSE between observed and predicted temperatures ranged between 0.15 and 0.5 °C with an overall average of 0.27 °C. Previous studies showed higher RMSE ranges, e.g., between 0.12 and 7.8 °C, with overall averages of 0.35, 0.42 and 2 °C. The new coefficient has also provided stable values at various seasons and minimised the number of required model inputs

ISOLATION, IDENTIFICATION AND MOLECULAR CHARACTERIZATION OF PECTINASE PRODUCING BACTERIAL ISOLATE Klebsiella oxytoca

Twenty two bacteria were isolated from soil samples local. were assayed for pectinolytic activity after optimization condition for pectinase production. isolate No. 22 showed high pectinase specific activity (91.4U/ml)  on glucose supplemented medium. the identification of the isolate revealed that it belongs to the Genus klebseilla bassed on morphological, biochemical characteristic, growth and molecular level 16s rRNA indicated that isolate was 99% similarity with Klebsiella oxytoca JKo3. Therefore, it was named Klebsiella oxytoca N22

Modelling the potential for multi-location in-sewer heat recovery at a city scale under different seasonal scenarios

A computational network heat transfer model was utilised to model the potential of heat energy recovery at multiple locations from a city scale combined sewer network. The uniqueness of this network model lies in its whole system validation and implementation for seasonal scenarios in a large sewer network. The network model was developed, on the basis of a previous single pipe heat transfer model, to make it suitable for application in large sewer networks and its performance was validated in this study by predicting the wastewater temperature variation across the network. Since heat energy recovery in sewers may impact negatively on wastewater treatment processes, the viability of large scale heat recovery was assessed by examining the distribution of the wastewater temperatures throughout a 3000 pipe network, serving a population equivalent of 79500, and at the wastewater treatment plant inlet. Three scenarios; winter, spring and summer were modelled to reflect seasonal variations. The model was run on an hourly basis during dry weather. The modelling results indicated that potential heat energy recovery of around 116, 160 & 207 MWh/day may be obtained in January, March and May respectively, without causing wastewater temperature either in the network or at the inlet of the wastewater treatment plant to reach a level that was unacceptable to the water utility

Optimisation of a fuzzy logic-based local real-time control system for mitigation of sewer flooding using genetic algorithms

Urban flooding damages properties, causes economic losses and can seriously threaten public health. An innovative, fuzzy logic (FL)-based, local autonomous real-time control (RTC) approach for mitigating this hazard utilising the existing spare capacity in urban drainage networks has been developed. The default parameters for the control algorithm, which uses water level-based data, were derived based on domain expert knowledge and optimised by linking the control algorithm programmatically to a hydrodynamic sewer network model. This paper describes a novel genetic algorithm (GA) optimisation of the FL membership functions (MFs) for the developed control algorithm. In order to provide the GA with strong training and test scenarios, the compiled rainfall time series based on recorded rainfall and incorporating multiple events were used in the optimisation. Both decimal and integer GA optimisations were carried out. The integer optimisation was shown to perform better on unseen events than the decimal version with considerably reduced computational run time. The optimised FL MFs result in an average 25% decrease in the flood volume compared to those selected by experts for unseen rainfall events. This distributed, autonomous control using GA optimisation offers significant benefits over traditional RTC approaches for flood risk management

Effects of oral ginkgo biloba extract on pregnancy complicated by asymmetrically intrauterine growth restriction: a double-blinded randomized placebo-controlled trial

Objectives: to evaluate the effect of oral ginkgo biloba extract (GB)) on asymmetrical intrauterine growth restriction (IUGR). Study Design: A randomized trial conducted at Assiut Women Health on 226 pregnant women with asymmetrical IUGR. The patients randomly received GB extract or placebo for 6 weeks. The main outcome measures were improvement in fetal weight and feto-maternal blood flow. The data were analyzed by Student’s t- test and chi-squared tests. Result: There was a significant increase in the estimated fetal weight in the GB group (3047+ 127 gm) when compared to the placebo group (2734+ 127 gm) (p= Conclusions: GB extract improves placental functions, Doppler indices and fetal weight in pregnancies complicated with IUGR fetuses

Effects of oral ginkgo biloba extract on pregnancy complicated by asymmetrically intrauterine growth restriction: a double-blinded randomized placebo-controlled trial

Objectives: to evaluate the effect of oral ginkgo biloba extract (GB)) on asymmetrical intrauterine growth restriction (IUGR). Study Design: A randomized trial conducted at Assiut Women Health on 226 pregnant women with asymmetrical IUGR. The patients randomly received GB extract or placebo for 6 weeks. The main outcome measures were improvement in fetal weight and feto-maternal blood flow. The data were analyzed by Student’s t- test and chi-squared tests. Result: There was a significant increase in the estimated fetal weight in the GB group (3047+ 127 gm) when compared to the placebo group (2734+ 127 gm) (p= Conclusions: GB extract improves placental functions, Doppler indices and fetal weight in pregnancies complicated with IUGR fetuses