Eight subsurface-flow wetlands in Texas, which represented different households and effluent quality and quantity, were evaluated to assess wastewater-quality improvement. All of the constructed ...wetlands consisted of lined gravel beds supporting aquatic plants. Analysis of the data revealed that the quality of influent varied among locations over the whole sampling period. On average, the BOD of the wetland effluents was below 20 mg/ml, and good reductions were achieved for ammonium nitrogen, phosphorus, total suspended solids, and volatile suspended solids. Populations of total and fecal coliforms were reduced by 90 99%. When chlorination was applied at one of the wetland sites, fecal coliform populations were reduced to less than 2 colony-forming units/100 ml.
An on-site wastewater treatment project with two separate drip fields was operated for 6 years and received no maintenance. The two drip fields (with different design configurations) contained ...pressure-compensating emitters (PC) and non-pressure-compensating emitters (NPC), respectively, and received wastewater with an average 5-day biochemical oxygen demand concentration of 23 mg/L. Flowrates of the PC emitters reduced from rated average of 3.50 to 1.00 L/h, and the average flowrate of the NPC emitters reduced from 2.00 to 1.53 L/h. The statistical uniformities were 48 and 71%, and the uniformity coefficients were 70 and 86% for PC and NPC emitters, respectively. Significant, but incomplete, recovery was achieved with field-flushing and consecutive shock-chlorination treatments of 500 and 1000 mg/L.
Subsurface drip distribution is an important on-site wastewater treatment technique widely used with various soil types and restricted site conditions. This study evaluated the performance of five ...subsurface wastewater drip products under eight pressures, ranging from 0 to 310 kPa. Results showed that Netafim Bioline pressure-compensating emitters (Netafim Irrigation Inc., Fresno, California) had an application uniformity coefficient of 95% and a coefficient of variance (C v ) of 4.9%. The average uniformity coefficient of Geoflow Wasteflow products (Geoflow USA, Charlotte, North Carolina) was 94.4%, with a C v value of 6.8%. Flowrate and pressure relationships were developed by analyzing low and normal operational pressure ranges, and R-square values ranged from 1.000 to 0.301. Geoflow pressure-compensating products were non-pressure-compensating emitters under low pressure. Netafim pressure-compensating emitters were partially pressure-compensating under low pressures. In normal operational pressure ranges, both Geoflow and Netafim products were fully pressure-compensating. Netafim pressure-compensating products were characterized as pressure-compensating over the full range of operational pressures.
Compost has been evaluated as a stormwater best management practice for erosion control, but site revegetation is the ultimate goal of most stormwater plans. In this study, three different composts ...applied as a surface layer or mulch at two depths of 5 and 10 cm were compared with topsoil and subsoil as a medium for crop growth and weed suppression during revegetation of a highway right-of-way. Compost was shown to be as effective as topsoil and subsoil controls for crop growth, while significantly reducing growth of weed species. There were no significant differences between 5- and 10-cm depths of composts, indicating that the shallower depth would be adequate for establishing a cover crop and achieving weed suppression. Compost mulches offer promising opportunities for crop and weed management during revegetation of roadsides and other disturbed landscapes.
Food-service establishments that use on-site wastewater treatment systems are experiencing pretreatment system and/or drain field hydraulic and/or organic overloading. This study included ...characterization of four wastewater parameters (five-day biochemical oxygen demand ${\rm BOD}_{5}$ ; total suspended solids TSS; food, oil, and grease FOG; and flow) from 28 restaurants located in Texas during June, July, and August 2002. The field sampling methodology included taking a grab sample from each restaurant for 6 consecutive days at approximately the same time each day, followed by a 2-week break, and then sampling again for another 6 consecutive days, for a total of 12 samples per restaurant and 336 total observations. The analysis indicates higher organic $({\rm BOD}_{5})$ and hydraulic values for restaurants than those typically found in the literature. The design values for this study for ${\rm BOD}_{5}$ , TSS, FOG, and flow were 1523, 664, and 197 mg/L, and 96 L/day-seat respectively, which captured over 80% of the data collected.
The components of this management system include automation of the check gates (used to control water levels in the canals), head gates, and flow-measurement structures; software to automate the ...water order and billing system; and software to calculate the water mass balance that is needed to support water orders and compare recommendations to actual measurements. ...last The third component of the water management system is the dam-release calculator.
Compost blanket applications from three sources in Iowa were compared to two conventional soil treatments on a highway embankment. Composts were applied as blankets over the existing subsoil at 5- ...and 10-cm depths. A topsoil treatment, a conventional Iowa Department of Transportation method, was applied at a depth of 15-cm. Rainfall was applied using a rainfall simulator at a target intensity of 100 mm/hr. Plots were measured for performance based on runoff, interrill and rill erosion, cover crop production, and water quality for two different conditions. Plots were sampled shortly after construction to simulate construction activities at startup, and six weeks after cover crop establishment. Compost applied as a surface layer or mulch has been compared with topsoil and subsoil as a media for crop growth and weed suppression during revegetation of a highway right-of-way. In this study compost was shown to be as effective as topsoil and subsoil controls for crop growth, while significantly reducing growth of weed species. There were no significant differences between 5- and 10-cm depths of composts, indicating that the shallower depth would be an adequate depth for establishing a cover crop and achieving weed suppression. Compost mulches offer promising opportunities for crop and weed management during revegetation of roadsides and other disturbed landscapes. Interrill runoff samples were collected on all treatments for the 1 st hour after runoff began. Compost application depth was not an important factor in measured interrill erosion rates. Compost treatments had significantly lower interrill erosion rates compared to topsoil and control treatments on un-vegetated plots. Rill erosion was measured on treatments using rainfall simulation at a target rate of 100 mm/hr and adding 5 inflows at the top of the rill on both vegetated and un-vegetated plots. Rill erodibility and critical shear values were calculated for all treatments using the shear stress model, but R-squared values were lower on composts compared to the two soils. Runoff from compost and soil treatments resulted in one or more of the composts containing significantly higher concentrations of N, P, K, and nine heavy metals than the control soil or the topsoil. Similarly, soluble and adsorbed concentrations of nutrients and metals contained in runoff and erosion products exported from the compost-treated test plots were generally much higher than those from the topsoil and control plots. The Water Erosion Prediction Project (WEPP) model was used to evaluate solids loss and runoff from the application of composts and two conventional soil treatments on a backslope and foreslope application at four different slopes (5%, 10%, 20%, and 30%). The results of calculated solids loss and runoff were coupled with water quality data to determine the environmental impacts of applying composts. (Abstract shortened by UMI.)
Participants in ASAE's first student environmental design competition won more than a cash prize or trophy could ever give them. They walked away with a real-life experience that will help them in ...future careers. The competition attracted student teams from throughout North America.
The great Society Persyn, Russell
Resource,
11/1997, Volume:
4, Issue:
11
Trade Publication Article
The 1997 American Society of Agricultural Engineers International Meeting focused on opportunity, diversity, transition, and responsiveness. More than 50 industry representatives and over 100 ...students attended the Student/Industry Exchange and the Student-Mentor program.
The 1997 ASAE Annual International Meeting promises to provide both opportunity and ability, with the help of students and industry representatives. The Student/Mentor program is discussed.
