Ammonia is difficult to measure, especially for the dusty environment and relatively high ammonia levels found in poultry concentrated animal feeding operations (CAFO's). Literature and discussions with operators suggest that its measurement and control is highly desirable with significant economic, health and regulatory impacts. A sensor with suitable sensitivity, range and durability would find additional significant applications in monitoring waste lagoons, feedlots, or land where waste is applied. However, there are no commercially available devices that are sufficiently economical, robust, and practical for use in a typical CAFO to control ammonia exposure levels, ventilation, air-quality control or feeding systems, and environmental emissions. The optical ammonia monitor described in this proposal provides a unique, low-cost sensor system resistant to the fouling and poisoning that plagues both inexpensive and high-cost conventional instrument systems. Components of the system have been successfully deployed for leak monitoring in ammonia refrigerated controlled-atmosphere storage rooms and for human breath-testing where it has been shown to measure very low concentrations of ammonia. The development described in this proposal will extend the measurement range of the sensor system and develop quantitative algorithms for translation of the optical signals to ammonia levels. After modifications to the instrument that allow for up to one-month of unattended operation, these ammonia sensor systems will then be tested in an environmental chamber over a range of ammonia, humidity and temperature conditions followed by tests in an operational poultry house. OBJECTIVES: This project addresses agricultural needs in Concentrated Animal Feeding Operations (CAFO) for low-cost, low maintenance, continuous ammonia-monitoring systems to help ensure the health of animals and workers, provide economic benefits to the farms, as well as meet ammonia emission regulations of the US and Europe. It develops ammonia sensor membranes and instrumentation to quantitatively measure ammonia over a range of concentrations found at CAFOs. Most importantly, it addresses the problem of working reliably over periods of months in the dusty, high ammonia-level environment found in and around agricultural buildings. Sensor membranes we have previously constructed are designed for measurement of ammonia over limited concentration ranges of 0-5 ppm, 2-50 ppm, and 40-2,000 ppm. A multi-wavelength optical instrument has been built that measures our ammonia sensitive membranes over relatively narrow ranges. This predecessor sensor system was optimized for highly sensitive but non-quantitative measurements. Our overall objective is to adapt this optical sensing technology to be useful for long-term ammonia monitoring and control in a variety of agricultural buildings and applications. Our Phase I objectives will focus more specifically on adaptation and performance of the system under conditions found in poultry CAFO operations. Our Phase I objectives are to: 1. Optimize the optical ammonia sensors to extend the ammonia measurement range to a minimum of 5 - 100 ppm. 2. Develop robust signal processing algorithms to convert the optical signals to PPM ammonia. 3. Make engineering changes to the instrument allowing for battery operation, manual data collection, and automated data storage for up to 1 month in a poultry house environment. 4. Demonstrate and confirm the response characteristics of the ammonia monitor in a controlled environmental chamber using a variety of ammonia, humidity, temperature and interfering gas conditions that mimic those likely to be found in a poultry facility. 5. Demonstrate the performance feasibility for use of the Pacific Technologies' optical ammonia gas monitor for real-time measurement of ammonia in a poultry facility over a 1 month period. APPROACH: Our summary objectives are to build and test an ammonia sensor system capable of measuring 5-100 ppm ammonia gas in conditions found in a poultry breeder CAFO environment. We plan to adapt a multi-wavelength optical ammonia sensor and instrument previously developed for making highly sensitive but non-quantitative measures over narrow ranges of ammonia. Specific modifications are outlined that allow us to demonstrate our approach's utility. Our Phase I work has five major objectives. The first objective is to increase the ammonia concentration range measured by the system. Phase I focuses on optimizing the sensor membrane's ammonia-response range while Phase II will optimize the instrument's measuring capability. Sensor optimization will take two related development paths: (i) utilization of ammonia sensitive indicators suited to the 5-50 ppm range and (ii) utilization of multiple indicators with sensitivities that span the desired ammonia range. The second objective is to provide a quantitative measure of ammonia. Spectral changes in the membrane will be measured as a function of ammonia concentration and various non-specific effectors (e.g. humidity and dust) using both a spectral-scanning instrument (SkinSkan) and our 4-wavelength instrument. Sensor candidates will be measured under a variety of defined conditions and a multi-parameter regression will be developed that minimizes the standard error over a 5-100 ppm ammonia range. The third objective is to build in several features to the instrument that allow for simple deployment and use in a poultry house. These features include a small built-in digital indicator of the ammonia concentration, a humidity sensor and provision for up to 1 month of battery operation as well as increasing the memory size to allow storage of more (longer) data periods. Our fourth and fifth objectives are to test our system's ammonia response, accuracy and stability in both controlled lab conditions and in actual field evaluations. A small environmental test-chamber will be built that can modulate ammonia, humidity, and temperature conditions found in a typical poultry house using either injected ammonia gas or a small manure box in the chamber. Sensors will be tested in conditions representative of those found in layer barns. At least three levels of relative humidity (50, 65 and 80% RH) and two temperature levels (20C, 30C) in conjunction with five levels of ammonia concentration will be tested. Finally, we will place three optical sensing instruments in a poultry facility and monitor them for one month. The instrument will automatically collect optical, RH and calculated ammonia data and a worker will periodically measure and record the ammonia levels near the sensors using a conventional hand-held meter. In one months time, there will be sufficient dust accumulation to judge whether this or any other gases and conditions in the barn environment adversely affect the sensor performance. At the test conclusion, the optical sensor data will be compared to the "conventional" data for its accuracy and general performance
