Wastewater Treatment Plant City Of Valentine FRANK X. SPENCER & ASSOCIATES Consulting Civil Engineers & Land Surveyors INTERNSHIP PROJECT PRESENTATION BAAS 4392 The University of Texas at the Permian Basin December 2010 by Rojelio Alvarado

Presentation Outline Part I - INTRODUCTION Reports’ Objective Needs for project Part II – PROJECT DESCRIPTION Part III – FUNDING Part IV – DESIGN/CONSTRUCTION Waste Water Collection System Headworks Treatment Process (Integrated Facultative Pond) Treatment Process (Storage Pond) Treatment Process (Irrigation pond/field): Part V - CLOSING

Part I - INTRODUCTION Report Objective: My report’s objective will be to describe the waste water treatment process of a small city plant and the construction of plant with its distribution lines which was being constructed during my internship period. Engineering services for the project was provided by the Civil Engineering firm of Frank Spencer & Associates, (FXSA). Project was approximately 70% completed at the end of my report. Need for Project: This project was being done to address the sanitary sewer services for the community which did not have any. The small town’s residents had been on septic tanks or cesspool type sewer systems. Part I - INTRODUCTION

Part II – PROJECT DESCRIPTION The project that I worked on during my Internship period was the construction of a waste water treatment plant and the gravity gathering lines. The waste water project was for the town of Valentine Texas. This town has 221 residents and is located 34 miles west of Marfa Texas. The construction project consisted of constructing all of the main gravity lines, 36 manholes and a big lift station. Approximately one quarter mile outside of town is the location of the waste water treatment plant (WWTP). This plant consists of an integrated facultative pond, a storage pond, head works, irrigation/recirculation pump station, maintenance building and an irrigation pond/field. The WWTP is a pond/lagoon treatment system with effluent land irrigation application. The plant removes BOD and suspended solids to the level provided by primary treatment followed by land application. The treated effluent is stored in the storage pond before being pumped to land application. The plant is designed to handle a flow of 40,000 gallons per day.

Part III – FUNDING The City of Valentine requested and qualified for funding through the American Recovery and Reinvestment Act (ARRA), to construct the new waste water treatment facility along with waste water collection system.

Part IV – DESIGN/CONSTRUCTION

Waste Water Collection System: The gravity gathering lines is the pipeline network of PVC pipeline that collects the waste water from residential or commercial building. These pipelines are usually installed along the alleys where they collect waste water from the houses. The pipelines are usually line segments 300’-400’ in length and connect with each other at manholes. These manholes are concrete vessels that are buried underground and have a heavy cast iron cover that can withstand vehicle loads. The manholes are not meant for collecting waste water, t hey are used by maintenance personnel for cleaning out the plugged line segments. This network of pipeline is designed with a controlled elevation where they start from a shallow elevation usually around four feet deep and start sloping down towards a deeper elevation. Eventually the line is too deep to construct, so at this point a lift station will usually be installed.

Typical Manhole Installation

Lift station This lift station consists of a deep cylindrical tank with pumps which collect collects the waste water and pumps it to a shallower line or as in our case, it pumps directly to the headworks at the waste water treatment plant.

Headworks Raw wastewater is delivered from the collection system to the treatment plant is first received at the headworks facility. It is called this because it is at the head of the plant. No biological treatment occurs, its purpose at this stage is to remove floatables and other solids from the stream to avoid damage to pumps and plant piping. At the headworks five functions are performed: sampling, flow measurement, chemical addition, screening, and grit removal. The bar screen’s objective is to remove solids greater than one inch in size, thereby reducing the solids and BOD load on the downstream processes. Screen clogging reduces the space for water flow thereby reducing the flow rate of water. For measuring the flow rate and volume of the waste water as it passes through the headworks a Parshall flume is used. The 2” parshall flume installed on this project was precast out of fiberglass construction and anchored down to the concrete after the headworks was poured. Water coming into the flume is forced by a bottleneck and by a bottom dip to pass over a critical depth where it goes from river-speed motion into rapid speed motion. Due to this transition of speed, water flow and volume can be measured from the water levels before the neck. The flume is attached with a transducer which displays flow rate of water with a digital screen. Once the waste water passed this point it will exit the headworks and flow down a gravity line into the concrete pit of the Integrated Facultative Pond where it will start its treatment process.

Headworks Parshall flume

Treatment Process (Integrated Facultative Pond): After the waste water has been screened and measured it will flow into the integrated facultative pond (IFP). This pond has a surface area of 0.55 acres and a volume of 3.2 acre feet. The bottom elevation of the pond is 4403 ft and the top of the embankment elevation is 4415 ft. During normal operation, water elevation is expected to be at 4411 ft, thereby having a depth of 8 feet. In the event of continuous odor problems from the IFP, a recirculation pump will be used to circulate the waste water from the storage pond back to the IFP. Approximately 20% of the effluent coming out of the storage pond will be re-circulated. If odor problems continue, the percentage of effluent recirculated will be increased by 10 percent every week to a maximum not to exceed 50% recirculation. Construction of both IFP and storage ponds was dug out with a bulldozer and scraper. The earth that was cut was used for building up the pond’s embankments. The ground was moistened and compacted. Once the concrete pit was constructed, both ponds were lined with a poly membrane liner. The HDPE lining had two layer of 60mil liner with a poly mesh layer.

Treatment Process (Integrated Facultative Pond):

Treatment Process (Storage Pond): When the IFP pond’s water level reaches a certain level, it will overflow into the storage pond. The storage pond feeds the irrigation/recirculation pump basin, which will circulate the waste water back to the IFP or direct it to the irrigation field. The storage pond has a surface area of 0.62 acres and a volume of 3.l5 acre feet. The bottom elevation of the pond is 4403 ft and berm elevation is 4415 ft. The water level will vary throughout the year.

Treatment Process (Storage Pond):

Treatment Process (Irrigation pond/field): The treated effluent from the IFP will be stored in the storage pond and be used for land application via surface irrigation. The irrigation will be done by a water reel that will be watering the field with a sprinkler head. The entire irrigation area on the treatment plant site is of 11 acres. The number of acres to be irrigated will depends on the flow rate of the wastewater. Alfalfa will be the major crop to be irrigated. Once in a period of three years, alfalfa needs to be replaced with Jose Wheat Grass. This will maintain the productivity of alfalfa.

Treatment Process (Irrigation pond/field):

Since my internship period has come to an end. The project is still not complete and will lack the pump stations in full operation, electrical work, a finished maintenance building and road construction and paving. The closing out of the project will require that the contractor have all of the construction work completed without any pending punch list items. The contractor will provide his marked up set of plans showing the as built changes done during construction, along with equipment operation manuals, personnel training and provide proof that all sub-contractors have been paid off. CLOSING