PROJECT REPORT TITLE OF PROJECT:

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1 PROJECT REPORT TITLE OF PROJECT: Demonstration of Real-Time Monitoring Systems to Increase the Intensity of Lagoon Management and to Reduce Water Pollution From Overflows and Illegal Discharges. Name and Contact Information of the PIs: Saqib Mukhtar, 303-B Scoates Hall, 2117, TAMU, College Station, TX (979) , Brent W. Auvermann, 6500 Amarillo Blvd. West, Amarillo, TX (806) , Raghavan Srinivasan, 1500 Research Parkway Suite B223, College Station, Texas (979) , The goal of this project is to demonstrate the viability of a real-time monitoring and alarm system to alert the CAFO operator to imminent (a) encroachment on design runoff volumes in lagoon and (b) overtopping of the lagoon embankment. Specific water-quality objective of this on-farm demonstration project is to: Reduce the probability of illegal discharges by providing facility managers with real-time notice of critical water levels in anaerobic lagoons, levels requiring management attention to prevent overtopping or emergency-spillway use. Work Plan: 1. Purchase real-time liquid level monitoring equipment Progress to date: Two lagoon liquid level depth probes, a pressure transducer probe (PTP) and an ultrasonic probe (USP), data loggers, modems and other accessories were purchased for realtime lagoon depth monitoring and remote acquisition of depth data. 2. Install the monitoring equipment at a lagoon. Progress to date: The 2-cell anaerobic treatment lagoon at the Animal Science Teaching, Research and Extension Complex (ASTREC) was selected to test the monitoring equipment. Probes were installed in the second cell of this lagoon (Figure 1). Effluent from this cell is pumped to irrigate the pasture land in the vicinity. Two probes (PTP and USP) were lowered in the cell and tied to a pre installed depth marker (fiberglass staff with graduations) in the middle of this cell (Figure 2). This marker is currently used to visually assess the liquid level of the cell. 1

2 Cell 1 Cell 2 Figure 1. A 2-cell anaerobic treatment lagoon at the Animal Science Teaching, Research and Extension Complex (ASTREC). Marker Figure 2. Pressure transducer probe (left) and Ultrasonic probe (middle) being installed next to the existing depth marker. The schematic in Figure 3 shows exact locations of the two probes installed in reference to the lagoon bottom and the liquid level at the time of probe installation. Other accessories such as data loggers, modems, and a solar panel to charge batteries for data loggers, antennas, and modems were installed on site using an existing wooden post and a concrete pad (Figure 4). 2

3 Initial liquid Level when probe was installed 108" Existing depth marker Initial liquid Level 93" Liquid level at time x Ultrasonic Probe 44" Pressure Transducer Probe 38" Lagoon bottom Figure 3. Locations of pressure transducer probe (PTP) and ultrasonic probe (USP) in lagoon. Antenna with RF modem Solar panel and data loggers Figure 4. Data logging and communications equipment installed on site at ASTREC lagoon. 3

4 3. Monitor lagoon liquid level data continuously Progress to-date: In October 2003, the data logger for the PTP was connected to a cellular digital modem. A special Internet Protocol address issued by the Verizon Wireless Company and the software provided by the supplier of PTP system were used to establish communications with the data logger for downloading liquid level depths. This arrangement allows individuals to download real-time data from anywhere in the world using a computer and the internet. The modem for the PTP system was programmed to record the liquid level depth every 10 minutes on a continuous basis. The PTP system was programmed and tested to trigger a strobe light alarm if the liquid level rose above a pre determined critical height. During the first few days, the data down loaded from the probe was compared with the liquid level depth indicated by the pre existing depth marker in the lagoon cell. Additionally, this data was also compared with the liquid level depth measured by the USP. The USP system was also installed in October 2003 with the exception that no remote sensing of the data could be established. The radio frequency modems used to communicate with the data logger of this system were unable to send/receive signal beyond a 2 mile radius due to tree and building obstructions. This has restricted the data recording to on-site, once per week only, by physically reading the digital output from the data. A new set-up using a third modem and telephone (analog signal) communication was tested for the remote down loading of data from USP probe. It was confirmed that this set-up was operational and data could be downloaded successfully to a desktop or a laptop computer. Figure 5 shows the lagoon liquid level depths, rainfall data (obtained from the Easter wood airport, about 2 miles from the ASTREC) and dates when the effluent was pumped out from the lagoon cell between October 5 and November 5, The solid line is the 10-min continuous data from the PTP system downloaded via the internet. The squares and the triangles are the weekly USP and existing depth marker readings of the liquid level depth. It is clear that both probes are measuring the depths within one inch of that indicated by the marker. The response of rainfall and effluent pump out events on liquid levels of the lagoon is also evident from this figure. For example, a 3.01 inch rain event on October 9, raised the lagoon liquid level from 87 to 95 above the bottom followed by pumping of effluent on October 9 and 10 (nearly 350 gallons per min for a total of about 30 hours) reduced the liquid level from 95 down to 79 above the bottom. Figure 6 shows the resolution and scatter of the lagoon liquid level data collected every 10 minutes from the PTP for 22 hours on October 5. This data shows an increasing trend in the liquid level as influent from the first lagoon cell was flowing into this cell. The variation (fluctuations) among data points were within 0.1. These small variations are mostly attributed to the wave and wind action that sways the marker to which this probe is tied. 4

5 Lagoon Liquid Level PT probe (in) Utrasonic probe (in) Marker reading (in) Rain (in) h pumping Effluent Pumped out 23.4h pumping 6.2h pumping Pumping in progress Depth (in) Rain (in) /2 10/6 10/10 10/14 10/18 10/22 10/26 10/30 11/3 11/7 11/11 Date Figure 5. Lagoon liquid level depths, rainfall and effluent pumping events between October 5 and November 5,

6 Pressure Transducer Probe Measurements (10-min data) Depth (in) :48 PM 12:00 AM 1:12 AM 2:24 AM 3:36 AM 4:48 AM 6:00 AM 7:12 AM 8:24 AM 9:36 AM 10:48 AM October 5, 2003 Figure 6. Accuracy of the lagoon liquid level data collected every 10 minutes from the Pressure transducer probe. 4. Continue monitoring and summarizing data beyond project termination Progress to-date: The monitoring is expected to continue through May This is important for inspection of the physical condition and performance of these probes after a prolonged use in the wastewater. 5. Leverage demonstration results with grants supporting broader implementation of the real-time monitoring system in the Upper North Bosque River and Leon River watersheds Progress to-date: A USEPA 319 grant to demonstrate these systems in Leon and Bosque River watersheds was submitted to the Texas State Soil Water Conservation Board in September Using state-appropriated funds, support staff in Amarillo has been tasked with building a lagoon sludge-profiling system by basing an ultrasonic depth probe and a WAAS-capable global positioning system on a remote-control boat platform. This technology, adapted from a recent design by North Carolina State University, will be capable of measuring up to 18,000 6

7 sludge depths in ten minutes across the entire surface of an anaerobic lagoon or runoff holding pond. It appears that this sludge-profiling system will complement the real-time liquid-level monitoring system by providing not only a single-point sludge-depth measurement but also a more accurate estimate of the total sludge volume in a lagoon. Acknowledgements: We would like to thank TWRI for their financial support of this project; Mr. Greg Spanel, Systems Analyst with the Blackland Research and Extension Center, for his technical assistance; and Messrs. Daryl Spillman and Kenneth Pounder, ASTREC, for their cooperation. 7