Dr. K. Reddy

In this thesis I deal with the drainage of Hněvošice village (the village up to 2000 inhabitants). I made a technical and economic evaluation of three possible drainage systems (gravity sewers, vacuum sewers, pressure sewers). After assessing I have chosen one of them, the gravity sewers. Then I made a complete design of the sewers including design sewerage treatment plant.

Modelling wastewater temperature variations in a network of 3048 sewer pipes was achieved in this project. Recovering heat from sewers presents attractive options for producing clean energy. However, heat recovery from sewerage may result in wastewater temperature drops which may reduce the influent temperature at the wastewater treatment plant (WWTP). This drop in the WWTP influent temperature may result in the degradation of the biological treatment stage. Therefore, it is vital to predict the impact of recovering heat from sewers on the wastewater temperature. Sewer temperatures along with hydraulic data were measured for up to a year in four different Belgian sites. The measured data was utilised to calibrate a deterministic sewer pipe model that estimates the wastewater temperature variation along the sewer pipe profiles. The latter model was calibrated using data from two sites and then validated using independent data from the other two sites. The sewer pipe model was then further developed to model wastewater temperature variations in a large (3048 pipe) network. The large network model was tested by implementing three different heat recovery scenarios. It was observed that 9 MW may be recovered from the 3048 pipe network, serving a catchment with a population equivalent of 79500 inhabitants, without impacting negatively on the biological processes.

Following large rain events, extraneous freshwater contributions known as inflow and infiltration (I/I) bypass the storm sewer and enter the sanitary sewer system. In areas with a high water table, like Pinellas County and the surrounding Tampa Bay area, a majority of the wastewater infrastructure is submerged year round exacerbating the rate of groundwater infiltration. This excess flow overloads the existing wastewater infrastructure leading to sanitary sewer overflows (SSOs). These SSOs result in serious problems for municipalities and utilities across the country. This study was performed in order to assist Pinellas County Utilities in rehabilitating their southern sewer system. To do this, 59 sub-basins across 8 sewer zones were monitored through Pinellas County’s Phase 1 Flow Monitoring Program accounting for over 150 miles of gravity pipe. For each sub-basin, a flow meter was utilized to measure the flow from May to October, 2017. This data was analyzed to separately quantify the amount of infiltration and inflow in each sub-basin, respectively. Once quantified, a Severity Index (SI) was developed in order to give each sub-basin a score from 1-100 as it relates to the condition of the gravity mains in the sub-basin. The SI was a function of locational features available with the use of a Geographic Information System (GIS), such as the distance to water bodies and the soil hydrologic group (SHG), as well as intrinsic pipe properties including the type of pipe material and the age of pipe. Once validated with additional flow monitoring data, the developed SI framework can serve as an additional tool utilized by Pinellas County Utilities to identify areas in need of sanitary sewer rehabilitation. Being that the model only requires easily attainable information, this approach is less time consuming and is inexpensive as compared to traditional flow monitoring efforts. The study also examined the required monetary investment by Pinellas County Utilities in order to abate the 17 sub-basins observed in the study with an infiltration rate greater than the marginal threshold put forth by the Environmental Protection Agency (EPA). The study indicated that gravity pipe rehabilitation does not make a significant impact on groundwater infiltration until at least 30% of the gravity pipes in the sub-basin are lined. This is due to the groundwater table submerging a majority of the wastewater infrastructure. Once this threshold is met, lining was observed to abate groundwater infiltration linearly. The results found that $4.4 million will be required to rehabilitate the affected sub-basins to a marginal rate of infiltration and reduce the flow to South Cross Bayou Water Reclamation Facility (SCBWRF) by an average of 0.72 mgd (million gallons per day). On an annual basis, this reduction in flow will result in approximately $650,000 in treatment costs savings.

Modelling wastewater temperature variations in a network of 3048 sewer pipes was achieved in this project. Recovering heat from sewers presents attractive options for producing clean energy. However, heat recovery from sewerage may result in wastewater temperature drops which may reduce the influent temperature at the wastewater treatment plant (WWTP). This drop in the WWTP influent temperature may result in the degradation of the biological treatment stage. Therefore, it is vital to predict the impact of recovering heat from sewers on the wastewater temperature. Sewer temperatures along with hydraulic data were measured for up to a year in four different Belgian sites. The measured data was utilised to calibrate a deterministic sewer pipe model that estimates the wastewater temperature variation along the sewer pipe profiles. The latter model was calibrated using data from two sites and then validated using independent data from the other two sites. The sewer pipe model was then further developed to model wastewater temperature variations in a large (3048 pipe) network. The large network model was tested by implementing three different heat recovery scenarios. It was observed that 9 MW may be recovered from the 3048 pipe network, serving a catchment with a population equivalent of 79500 inhabitants, without impacting negatively on the biological processes. / INNERS project funded by EU Interreg IVB

No description available.

A single political issue, public financing of a sewage treatment facility for the city of Logan, was studied in an attempt to determine the effect of certain variables on the formation of public policy. The case study method of research was followed, and conclusions were based on data obtained through personal interviews as well as through study of public documents. Among factors which influenced the decisional process was the degree to which technological knowledge was accepted. Policies developed by the state legislature and the federal bureaucracy to deal with environmental pollution also affected the local situation. A conflict which arose over interpretation of certain of these policies was largely resolved in court.

The area of study is the Avery Drive drainage area. The objective of these projects is to alleviate frequent flooding at the Avery Drive neighborhoods. RC&A designed two options for improving the Avery Drive drainage area. Option one increases the capacity of the existing sewer system, and option two constructs a new storm drain system along Simon Street while keeping the existing system in place. Although both options offer preliminary solutions for alleviating flooding, the designs are unviable due to the lack of data that was available for the study. The following research will prove that RC&A fulfilled its contractual obligation of practicing due diligence by recommending further investigation to obtain valuable data for a complete and successful final design, rather than providing a solid recommendation based on existing data. / text

In this study, die-off patterns of helminth ova, fecal coliforms, and Salmonella spp. in biosolids were documented using three small-scale sand drying beds located in a greenhouse. Treatments involved tilling the biosolids with differing frequencies. The results indicate that the inactivation rate for helminth ova was 0.88, 0.55, and 0.22 eggs/4 g TS day-1 for the intensively-tilled, moderately-tilled, and control beds, respectively. Achievement of Class A criteria was only possible in the intensively-tilled bed by Day 70 of the experiment. Salmonella spp. were inactivated to Class A levels in 9 days for the intensively and moderately-tilled beds. Regrowth of Salmonella spp. occurred thereafter in all beds, but high levels were seen only in the control bed. Fecal coliforms reached Class A criteria late in the experiment. Tilling treatments enhanced the inactivation rate of helminth ova and offer a potentially cost-effective method of pathogen reduction.

The design of service connections to deeply buried sewers involves a number of challenges. In practice, the loads that develop from vertical risers can damage the Tee or Wye fitting to which it is connected. This thesis studies the expected loads and resistance of these connections, and provides some recommendations for the solution of this engineering problem. Laboratory tests have been performed to explore the capacities of the existing fittings both in air and when buried in uniform sand. A test procedure different from the standard quality control test methods described in ASTM F1336-02 is used to study the performance of the fittings in air. A special test configuration was also developed for an existing pipe test cell to explore the capacities of the existing PVC Tee and Wye fittings when buried in uniform sand. An analytical formula analogous to pile downdrag and numerical analyses have been used to evaluate the test results, to calculate the capacities of the buried heavy-wall fittings, and to explore the downdrag forces that develop along vertical risers. Through comparisons with experimental measurements, it was demonstrated that these methods of analysis can be used to estimate the downdrag forces and determine the adequacy of specific fittings to resist those forces. The major conclusions drawn for the specific fittings tested in this project are summarized as follows. When axially loaded in air, both Tee and Wye fittings experience plastic yield failure. When buried, the Tee fitting fractures or yields only along the base of the riser part; while the Wye fitting itself does not fail, the riser cracks near its base where it connects to the curved pipe (450 elbow) above the Wye. Both the capacities and stiffness of the buried fitting system (either Tee or Wye) are approximately linear functions of the confining stress supplied by the surrounding soil. The accumulated downdrag along the riser in the coarse-grained soil is much smaller than that in fine-grained soil. Various practical solutions for the vertical riser problem are then discussed and recommended. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2008-12-28 21:18:30.363