Browsing by Author "Gregory, Lucas"
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Item Demonstration and Transfer of Selected New Technologies for Animal Waste Pollution Control(Texas Water Resources Institute, 2009-04) Mukhtar, Saqib; Gregory, LucasThe Demonstration and Transfer of Selected New Technologies for Animal Waste Pollution Control project was conducted by the Texas AgriLife Extension Service and Texas Water Resources Institute and was designed as a means for evaluating animal waste treatment methods and their ability to remove phosphorus (P) from dairy waste. A variety of factors present in the North Bosque River watershed have led to the excessive loading of P and subsequent algal growth in the water body. As a result, the Texas Commission on Environmental Quality developed two Total Maximum Daily Loads (TMDLs) for the North Bosque River mandating that P loading to the water body be reduced by at least 50 percent. Upper portions of the North Bosque River watershed are home to numerous dairy operations that can be a source of manageable P and other nutrients to the watershed. Prior to the development of this project, dairy producers in the area were approached by different companies soliciting their respective products that ‘guaranteed’ P removal from their dairy waste and/or lagoons; however, the diary producers were not presented with scientific evidence to support these claims and were skeptical about actual results. This project was designed in response to the need for scientific evidence and evaluated the ability of four products/technologies to remove P from liquid dairy manure prior to its application on nearby fields. The program was set up so that an unbiased, third party laboratory analyzed samples collected from dairy waste prior, during, and after treatment by each respective product or technology to provide scientifically sound information to dairy producers so they can make an informed decision about implementing a specific treatment to reduce P from their dairies. Each technology provider utilized a different approach for applying or implementing their respective treatments; the providers were allowed to demonstrate their technology without any modifications recommended by Texas AgriLife Extension Service. Specific sampling procedures and locations were not consistent between each evaluation due to the nature of the technologies; two physiochemical methods treated the waste stream to separate solids and nutrients from liquid manure while two biological treatment methods utilized microbes to treat the entire lagoon. Though each technology resulted in improvements of lagoon characteristics, only the physiochemical treatments effectively removed more than 50 percent of P present in the dairy waste. As an addendum to the project, a demonstration was conducted to evaluate the feasibility of growing turfgrass on soils amended with byproduct from one of the physiochemical treatment evaluations. The large volume of solids remaining after treatment raised the question of how to effectively dispose of the solids in a beneficial way. The demonstration assessed the response of turfgrass growth and leachate/runoff water quality from small cylinders containing soils amended with the particular byproduct. Results showed that turf production increased as a result of the amendment and water quality was not drastically compromised. This report summarizes the results of each demonstrated product or technology and the turfgrass growth demonstration. It highlights both positive and negative aspects of each treatment methodology so producers who consider implementing one of the technologies may have science-based findings predicting respective performance.Item Field Demonstration of the Performance of a Geotube® Dewatering System to Reduce Phosphorus and Other Substances from Dairy Lagoon Effluent(Texas Water Resources Institute, 2009-01) Mukhtar, Saqib; Wagner, Kevin; Gregory, LucasTwo upper North Bosque River segments were designated as impaired in 1998 due to point source and nonpoint source (NPS) pollution of phosphorus (P) to these segments in the watershed. As a result, two Total Maximum Daily Loads (TMDLs) were applied which called for the reduction of annual loading and annual average soluble reactive P (SRP) concentrations by about 50%. This demonstration was conducted to evaluate the efficacy of a prospective new technology, the Geotube® dewatering system that may aid dairy farmers in reducing P from lagoon effluent to be applied to waste application fields and thus reducing NPS pollution. In this Geotube® dewatering system, effluent is pumped from the dairy lagoon using a PTO-driven chopper pump into a PVC pipe with a series of elbows that facilitate thorough mixing of the chemical pretreatment. Alum and a polymer are added to the effluent agglomerate solids and precipitate P as it flows through the elbows to the Geotubes®. Two 14’ x 50’ geotextile fabric tubes were installed on a 6 millimeter impermeable polyethylene sheet next to a primarily dairy lagoon that received flushed manure. After the tubes were filled, they were allowed to dewater for a period of 6 months. Rainwater typically sheds off of the tubes and does not soak into the tubes. At the first two sampling events in March and April 2005, samples of the dairy lagoon effluent, the lagoon effluent after the addition of the chemical pre-treatment, and the effluent dewatering from the tubes were taken and flow rates into the tube were measured. At the last sampling event in October 2005, samples of residuals and depth of the dewatered residuals were taken from both tubes. Samples from the three events were analyzed for concentration of solids, nutrients, metals and pH. Results showed that the Geotube® dewatering system performed very well in filtering solids from the dairy lagoon effluent, removing an average of 93.5% of the total solids between the two pumping and dewatering events of March and April. It was effective in removing nutrients and metals as well. The average percent reduction of SRP for the two events was very high at 85%. It should be noted that these findings were limited to the sampling of the tubes in March and April and the tubes continued to dewater for several months. Therefore, any changes in the concentration of the dewatering effluent, volatilizing solids and precipitating substances after the sampling events could not be accounted for. A brief economic analysis of this dewatering system was furnished by the technology provider. Cost estimates for a long-term dewatering system were $90,000 to treat 1.9 million gallons of dairy lagoon effluent containing 15+ years worth of nutrients and solids that settled to the bottom of the lagoon at a 2000 head lactating cow open-lot dairy. This estimate includes all capital and operating costs except removal of residual solids. Costs will vary depending on the size of the dairy and the length of time between lagoon treatments using Geotubes®.Item Field Demonstration of the Performance of an Electrocoagulation System to Reduce Phosphorus and Other Substances from Dairy Lagoon Effluent(Texas Water Resources Institute, 2009-01) Mukhtar, Saqib; Gregory, Lucas; Wagner, KevinTwo upper North Bosque River segments were designated as impaired in 1998 due to point source and nonpoint source (NPS) pollution of phosphorus (P) to these segments in the watershed. As a result, two Total Maximum Daily Loads (TMDLs) were applied which called for the reduction of annual loading and annual average soluble reactive P (SRP) concentrations by an average of 50%. This demonstration was conducted to evaluate the efficacy of a prospective new technology, an Electrocoagulation (EC) system, to potentially aid the dairy farmers in meeting the goals set by the TMDLs. This EC system used chemical pre-treatment to coagulate and separate solids in slurry pumped from the dairy lagoon, the liquid then flowed over charged iron electrodes giving off ions that cause coagulation and precipitation of P and other metals. The configuration of the system and its components varied from event to event. To accommodate these changes, the points at which samples were taken varied as well. At all sampling events, samples were taken from the lagoon effluent, the lagoon effluent after the addition of the chemical pre-treatments, the effluent from the EC system and the residual solids. Samples were also taken where the mixture exited the centrifuge after it was added to aid in removing solids. These samples were sent to the lab where they were analyzed for solids, nutrients, metals, pH, and conductivity. In order for the EC unit to function properly, the technology provider removed large amounts of solids from the raw lagoon effluent even though its solid concentration was a low 0.6 mg/L. By the time the treated effluent reached the EC unit, concentrations of many analytes were so low it is hard to conclude whether or not it is an effective component for treating dairy lagoon effluent. Samples of effluent from the centrifuge indicated that it was the most efficient component in the system as it removed larger amounts of solids, as well as more of the nutrients and metals than any other component in the system. Overall, the performance of the system was sporadic from event to event, which may be attributed to the changes in the system that occurred. However, it was consistently effective in reducing total phosphorus (TP) and SRP, on average reducing these constituents by 96% and 99.6% respectively from the dairy lagoon effluent. Some uncertainty surrounds the efficacy of this system to reduce both TP and SRP so efficiently because both these and other nutrients are not stable and do change form. Economic data shows that costs to treat dairy lagoon effluent were $0.12 per gallon ($120 per 1,000 gallons). This cost did not include removal of residual material from the farm and will vary depending on the number of cows and volume of process generated influent entering the lagoon. This price per gallon is considerably higher than traditional methods of sludge treatment that range from $5 to $32 per 1,000 gallons of treated effluent.Item Field Demonstration of the Performance of Wastewater Treatment Solution (WTS®) to Reduce Phosphorus and other Substances from Dairy Lagoon Effluent(Texas Water Resources Institute, 2009-01) Gregory, Lucas; Rahman, S.; Mukthar, SaqibIn 1998 two upper North Bosque River segments were designated as impaired due to point source and nonpoint source (NPS) pollution of phosphorus (P) in these segments of the watershed. As a result, two Total Maximum Daily Loads (TMDLs) were applied, which called for the reduction of annual loading and annual average soluble reactive P (SRP) concentrations by about 50%. Under the Clean Water Act (Section 319(h)), a new technologies demonstration project was funded by the U. S. Environmental Protection Agency (USEPA) Region 6 and administered by the Texas State Soil and Water Conservation Board (TSSWCB) for reducing water pollution associated with dairy animal production systems. As part of this demonstration, the efficacy of a prospective new technology (i.e. wastewater treatment solution, WTS®) was evaluated, which may assist dairy farmers in reducing P from lagoon effluent. In many cases, this effluent is applied to waste application fields (WAF) as irrigation water. Therefore, reducing P in the effluent can have a direct impact on NPS pollution in the watershed. Before treating a dairy’s anaerobic lagoon with WTS® and an oxygenating additive, O2T, three separate background (pre-treatment) samplings were conducted to gather baseline information on nutrients (e.g., total phosphorus [TP], soluble reactive phosphorus [SRP], and total Kjeldahl nitrogen [TKN]) and solids (e.g., total solids [TS], total suspended solids [TSS], total dissolved solids [TDS]) data prior to inoculation. Following the third pre-treatment sampling in September 2007, the anaerobic lagoon was treated with WTS® at an averaged application rate of 1 gallon/head as a start-up. Thereafter, WTS® was applied at a rate of 0.5 gal/100 head-day (based on 600 heads), while O2T was applied at a rate of 0.1 gal/100 head-day (based on 600 heads). To mimic the repeatability of lagoon treatment, two large tanks were filled with untreated flushed manure to assess the treatment effect on flushed manure from free-stall. Tank 1 (T1) was treated manually on a monthly basis, with WTS® at a rate of 16 oz (0.5 L) and with O2T at a rate of 7 oz (0.25 L) and Tank 2 (T2) was used as the control (no treatment was applied). Following treatment, lagoon samples were collected monthly or bi-monthly from two different profiles: lagoon supernatant (LS), sampled from the top of the liquid level to 2 ft (0.61 m) depth and lagoon profile (LP), sampled from the entire depth of the lagoon using a sludge judge (a sampling tube with a check valve at the bottom to take lagoon sample at different depths). For each LP and LS, 27 samples (3 samples per location × 9 locations) were collected during each sampling event. A set of 9 LP and 9 LS samples were mixed separately to get two composites of each for nutrients including P, solids, pH, conductivity and metals. Similarly, samples were collected from tank supernatant (1 ft or 0.30 m below liquid surface) and profile (from the entire depth of the tank) in each sampling event. During each sampling event, a total 36 (9 samples per tank × 2 tanks × 2 profiles) samples were collected from the two tanks. Each set of 9 tank supernatant and 9 tank profile sample bottles were mixed separately to get two tank supernatant (T1S and T2S) and two tank profile (T1P and T2P) composite samples of each for analysis. WTS® treatment was somewhat effective in reducing sludge depth by 10% compared to its pre-treatment level. This reduction of sludge depth was due to microbial treatment, which will likely improve lagoon effluent characteristics, increase lagoon capacity and reduce maintenance cost for this lagoon. This treatment system increases pH in the LS significantly as compared to LP. Similar to lagoon pH, the treated tank T1 had a slightly higher pH as compared to untreated tank T2 in both tank profiles, although differences were not statistically significant. There was no significant reduction in TS either in lagoon or tank environments due to WTS® treatment. Overall TSS was reduced by 7% and 9% for LP and LS, respectively, when concentrations of these parameters averaged across post-treatment events were compared with the averages across pre-treatment events. There were no differences in TSS concentrations of treated and untreated tank samples at either LS or LP. Following microbial treatment of the lagoon, TDS concentration both in LS and LP increased, although no significant differences were observed between the two profiles. Overall, the TDS concentration in LS was 13% higher than that of LP. There was not a significant reduction in TP in either lagoon sampling profile. TP concentration in the treated tank profile was reduced by 17%, yet increased by 2% in the untreated tank profile samples. However, TP reduction values for treated and untreated tank supernatant samples were 60 and 55%, respectively. This suggested that the differences in TP reduction between treated and untreated samples were due to treatment effects. SRP concentration in both LP and LS samples increased gradually, although differences were not significant between LP and LS. A similar SRP increasing trend was also observed for tank samples, but differed in that the treated tank had a higher SRP concentration than that of untreated tank samples, due to greater TDS in tank supernatant. TKN in LP and LS reduced by 29 and 19%, respectively, but a greater TKN reduction was observed in tank profile (60 and 47% in treated and untreated tank profile samples, respectively) and tank supernatant samples (88 to 86% in treated and untreated tank supernatant samples, respectively) as compared to lagoon samples. Following the microbial treatment, the conductivity and potassium (K) concentration increased in both profiles of the lagoon and treated tank (T2). Three chemical quality parameters indicate the effectiveness of a wastewater treatment system such as biological oxygen demand (BOD), suspended solids, and TP (van Loon and Duffy 2000). Suspended solids and TP were both monitored in this study and had insignificant variation between pre-treatment and post-treatment. The purpose of this study was to evaluate the effectiveness of WTS® in reducing P and other substances from lagoon effluent to be applied to WAFs. Therefore, this treatment system was not very effective in reducing phosphorus and other nutrients from the lagoon effluent, especially soluble parameters. Conclusions indicate that more studies are needed to assess the effectiveness of this treatment over a longer time period.