Septic Waste Research Articles

Extent of Nitrate and Nitrite Pollution in Ground Water of Rural Areas of Lucknow, U.P., India

The present world is facing problems with a wide variety of pollutants. Water pollution is a major global problem. It has been suggested that it is the leading worldwide cause of deaths and diseases and that it accounts for the deaths of more than 14,000 people daily in Lucknow Capital of Uttar Pradesh in India.Nitrate and Nitrite pollution is one of groundwater’s most commonly identified contaminants, an indicator of serious pollution as they are associated with septic waste and agricultural endeavours, leads to numerous health problems to human beings and animals.4 rural areas of Lucknow were selected and 15 samples from each station to check the level of nitrite and nitrate parameters in groundwater. Further our studies reveal that the extent of nitrate and nitrite varied with reference to sampled site and maximum nitrate was found to be 250.224 and maximum nitrite was 1.8998 both are high.

Hydrologic fragmentation-induced eutrophication in Dove Sound, Upper Florida Keys, USA

Anthropogenic impacts to island systems can have deleterious effects on coastal aquatic ecosystems. These effects can alter water quality, primary production as well as habitat. Land development often fragments hydrologic connectivity within aquatic ecosystems forcing alterations in nutrient transport and increases the potential for eutrophication. Dove Sound, a tidal lagoon located in the Upper Florida Keys on Key Largo, has been subjected to anthropogenic influences of land development during the last century. To investigate these influences a short sediment core was collected from within Dove Sound and investigated using 210Pb dating, stable isotopes of carbon and nitrogen, and sedimentary pigments. Results indicated that Dove Sound has undergone eutrophication and the primary producer community structure has shifted from dominantly macrophytic to a system that supports substantial algal production. While septic waste was a possible source for eutrophication, low δ15N did not support this conclusion. However, the timing of the shifts in Dove Sound along with indicators of anoxia leads to the conclusion that fragmentation caused by the construction of a railroad was the root cause. The hydrologic fragmentation reduced the flushing rates, thereby enhancing anoxic conditions in the system and increasing the internal nutrient loading.

Roadside ditches as conduits of fecal indicator organisms and sediment: Implications for water quality management

Roadside ditches are ubiquitous, yet their role in water pollution conveyance has largely been ignored, especially for bacteria and sediment. The goal of this study was to determine if roadside ditches are conduits for fecal indicator organisms and sediment, and if land use, specifically manure amendment, affects the concentrations and loadings. Seven roadside ditches in central New York, adjacent to either manure amended fields or predominately forested land, were monitored for one year for Escherichia coli (E. coli), total suspended solids (TSS) and flow. E. coli concentrations in water samples following storms averaged 4616 MPN of E. coli/100 mL. Concentrations reached as high as >241,960 MPN of E. coli/100 mL and frequently exceeded New York State and US EPA recommendations. Concentrations peaked in both summers following manure spreading, with declining levels thereafter. However, viable organisms were detected throughout the year. The concentrations were also high in the forested sites, with possible sources including wildlife, pets, septic wastes and livestock. E. coli concentrations and loadings were related to TSS concentrations and loadings, whether manure had been spread in the last 30 days and for concentrations only, antecedent rainfall. Viable E. coli were also present in ditch sediment between storm events and were available for resuspension and transport. Total suspended solids concentrations averaged 0.51 g/L and reached as high as 52.2 g/L. Loads were similarly high, at an average of 631.6 kg/day. Both concentrations and loads tended to be associated with discharge and rainfall parameters. The cumulative pollutant contribution from the ditch network was estimated to be large enough to produce detectable and sometimes high concentrations in a receiving stream in a small, rural watershed. Roadside drainage networks need to be actively managed for water quality improvements, because they capture and rapidly shunt stormwater and associated contaminants to streams.

Catchment source contributions to the sediment-bound organic matter degrading salmonid spawning gravels in a lowland river, southern England

The ingress of particulate material into freshwater spawning substrates is thought to be contributing to the declining success of salmonids reported over recent years for many rivers. Accordingly, the need for reliable information on the key sources of the sediment problem has progressed up the management agenda. Whilst previous work has focussed on apportioning the sources of minerogenic fine sediment degrading spawning habitats, there remains a need to develop procedures for generating corresponding information for the potentially harmful sediment-bound organic matter that represents an overlooked component of interstitial sediment. A source tracing procedure based on composite signatures combining bulk stable 13C and 15N isotope values with organic molecular structures detected using near infrared (NIR) reflectance spectroscopy was therefore used to assess the primary sources of sediment-bound organic matter sampled from artificial spawning redds. Composite signatures were selected using a combination of the Kruskal–Wallis H-test, principal component analysis and GA-driven discriminant function analysis. Interstitial sediment samples were collected using time-integrating basket traps which were inserted at the start of the salmonid spawning season and extracted in conjunction with critical phases of fish development (eyeing, hatch, emergence, late spawning). Over the duration of these four basket extractions, the overall relative frequency-weighted average median (±95% confidence limits) source contributions to the interstitial sediment-bound organic matter were estimated to be in the order: instream decaying vegetation (39±<1%; full range 0–77%); damaged road verges (28±<1%; full range 0–77%); septic tanks (22±<1%; full range 0–50%), and; farm yard manures/slurries (11±<1%; full range 0–61%). The reported procedure provides a promising basis for understanding the key sources of interstitial sediment-bound organic matter and can be applied alongside apportionment for the minerogenic component of fine-grained sediment ingressing the benthos. The findings suggest that human septic waste contributes to the interstitial fines ingressing salmonid spawning habitat in the study area.

An evaluation of breeding conditions of flies and optimum food waste rations for effective composting in Municipal Solid Waste composting site in Southern Sri Lanka

Composting is effective way of solving problems associated with solid waste management. Some of the main issues associated with municipal solid waste composting are the increase of food waste percentage and development of breeding conditions favourable for various fly species causing public health issues. Experimental composting piles were constructed by changing food waste composition (0%, 25%, 50%, 75%), roofing and outer covering of the piles to estimate the composting efficiency and fly breeding conditions. House fly (Musca domestica) and fruit fly (Drosophila melanogaster) was associated with food and vegetable waste and blowflies (Calliphorid species) with septic and fish waste. Optimum composting efficiency and minimum fly emergence was recorded for the piles containing 50% food waste and 50% garden waste and constructed under the roof cover. Covering of piles containing food and vegetable waste, with a clean garden waste outer cover reduced the incidence of fly breeding. The findings of this study suggest that proper combination of bulking agents with food waste is essential for effective composting. Fly management require a good understanding of composting process and relationship between fly breeding conditions.

Design and development of decentralized water and wastewater technologies: a combination of safe wastewater disposal and fertilizer production

Modern wastewater treatment plants are often inappropriate for communities in developing countries. Such communities lack the funding, resources and skilled labour required to implement, operate, and maintain these plants. This research was conducted to investigate and establish an appropriate wastewater treatment system for the district of Gunung Kidul, Indonesia. Due to its lack of water during the dry season, this district is considered one of the poorest areas in the nation. First, wastewater was stored in septic tank units for a retention time of 26 days. Anaerobic conditions occurred, resulting in an 80% reduction of initial COD. The retained sludge was well stabilized with great potential, if dewatered, for reuse as fertilizer. Consequently, supernatant was separated for experiments consisting of lab scale aerobic sand filtering unit. Through filtration, further removals of COD (about 30%) and pathogens were achieved. Rich in nitrogen, the resulting effluent could be used for irrigation and soil conditioning. With faecal sludge and also a mixture of septic sludge and food waste, the hydrolysis stage of anaerobic digestion was examined. This paper discusses the laboratory findings in Karlsruhe and the design and implementation of a treatment system in Glompong, Indonesia.

Use of Environmental Isotopes (13C, 15N, and 18O) for Evaluating Sources and Fate of Nitrate and Tetrachloroethene in an Alluvial Aquifer

Environmental isotopes and geochemical parameters were used to evaluate the sources and fate of nitrate (NO− 3) and tetrachloroethene (PCE) in an alluvial contaminated aquifer. Isotope data and redox parameters data indicated that biodegradation does not play any role in the attenuation of these compounds along the groundwater flow system. Furthermore, nitrate isotopes and concentration data allowed the authors to distinguish two nitrate inputs and relate them to their possible sources. The primary source originates from septic waste and the secondary source is associated with nitrogenous fertilizer application. Regarding PCE, the δ13C values do not change for approximately 1000 m along the groundwater flow system despite large decreases of PCE concentration, thus confirming that physical processes do not alter the isotopic composition of organic compounds; this finding has a significant implication for the use of carbon isotope ratios for fingerprinting sources of PCE in VOC plumes. This study has shown that combined use of environmental isotopes and geochemical parameters is an efficient approach for water resource management studies in sites polluted by various types of contaminants.

Compostagem aeróbia conjugada de lodo de tanque séptico e resíduos sólidos vegetais

O lodo sanitário, principal subproduto do tratamento de esgotos, constitui um dos maiores problemas ambientais urbanos da atualidade. Em meio a este contexto, objetivou-se nesse estudo avaliar o processo da compostagem conjugada de lodo de tanque séptico (LS) e resíduos sólidos vegetais (RV) e determinar a importância da temperatura para o processo de sanitização do substrato tratado. O experimento, inteiramente casualizado com três tratamentos e três repetições, consistiu de nove reatores aeróbios com 100 litros de capacidade. Os resíduos foram utilizados nas seguintes proporções - T1: 100% RV; T2: 5% LS + 95% RV; T3: 10% LS + 90% RV. A compostagem aeróbia conjugada mostrou ser uma alternativa viável para destruição de ovos de helminto e estabilização dos resíduos, sendo fundamentais para tal, a temperatura, o pH e as relações ecológicas presentes nos reatores.

Using the Cl/Br ratio as a tracer to identify the origin of salinity in aquifers in Spain and Portugal

Summary A study on the applicability of the Cl/Br molar ratio for identifying the origin of groundwater salinity is presented according to the experience gained in Spain and Portugal. Cl/Br ratios in atmospheric bulk deposition have helped to distinguish groundwater in which Cl derives only from atmospheric sources, from groundwater in which Cl is contributed by endogenous, lithological or anthropogenic sources. Considering the seawater Cl/Br ratio of 655 ± 4, Cl/Br ratios may be increased up to 1500 in groundwater by the addition of wastewater loaded with NaCl or leaching of solid waste, and decreased to 300 by the use of Br-based pesticides or leaching farm-animal or septic waste. Leaching and dissolution of natural and industrial NaCl, and of gypsum-rich formations containing some NaCl may yield Cl/Br ratios between one thousand and several thousand, although leaching of potassium halides near salt mines produces Cl/Br ratios below the seawater ratio. When Cl content in groundwater is not affected by extreme evaporation (up to halite saturation at ∼6.2 mol L −1 of NaCl) and if there are no other Cl sources, recharge by rainfall can be estimated by relating Cl in atmospheric bulk deposition to derived groundwater. The Cl/Br ratio appears to be a good tracer for discriminating non-atmospheric Cl contributions to groundwater, provided chemical analyses are accurate, since its variability is not wide. Data have been collected from different areas of Spain and Portugal and are explained and illustrated by two cases described in detail, the Donana aquifer in southwest Spain and the Canary Islands, both showing the mixing paths.

Eutrophication study at the Panjiakou-Daheiting Reservoir system, northern Hebei Province, People's Republic of China: Chlorophyll- a model and sources of phosphorus and nitrogen

Concentrations, loads, and sources of nitrate and total phosphorus were investigated at the Panjiakou and Daheiting Reservoir system in northern Hebei Province, People's Republic of China. The Luan He River is the primary source of water to these reservoirs, and the upstream watershed has a mix of land uses including agriculture, forest, and one large urban center. The reservoirs have a primary use for storage of drinking water and partially supply Tianjin City with its annual needs. Secondary uses include flood control and aqua culture (fish cages). The response of the reservoir system from phosphorus input, with respect to chlorophyll- a production from algae, was fitted to a model of normalized phosphorus loading that regresses the average summer-time chlorophyll- a concentration to the average annual phosphorus concentration of the reservoir. Comparison of the normalized phosphorus loading and chlorophyll- a response of this system to other reservoirs throughout the world indicate a level of eutrophication that will require up to an approximate 5–10-fold decrease in annual phosphorus load to bring the system to a more acceptable level of algal productivity. Isotopes of nitrogen and oxygen in dissolved nitrate were measured from the headwater streams and at various locations along the major rivers that provide the majority of water to these reservoirs. Those isotopic measurements indicate that the sources of nitrate change from natural background in the rivers to animal manure and septic waste upstream of the reservoir. Although the isotopic measurements suggest that animal and septic wastes are a primary source of nutrients, measurements of the molar ratio of nitrogen to phosphorus are more indicative of row-cropping practices. Options for reduction of nutrient loads include changing the management practices of the aqua culture, installation of new sewage treatment systems in the large urbanized area of the upper watershed, and agricultural management practices that would reduce the loading of nutrients and soil erosion from that land use.

Incidence of the Enterococcal Surface Protein (esp) Gene in Human and Animal Fecal Sources

The occurrence of the enterococcal surface protein (esp) gene in the opportunistic pathogens Enterococcus faecalis and E. faecium is well-documented in clinical research. Recently, the esp gene has been proposed as a marker of human pollution in environmental waters; however, information on its relative incidence in various human and animal fecal sources is limited. We have determined the occurrence of the esp gene in enterococci from human (n=64) and animal (n=233) fecal samples by polymerase chain reaction using two primer sets: one presumably specific for E. faecium (esp(fm)) and the other for both E. faecalis and E. faecium (esp(fs/fm)). We believe that this research is the first to explore the use of esp(fs/fm) for the detection of human waste in natural environmental settings. The incidence in human sources was 93.1% esp(fm) and 100% esp(fs/fm) in raw sewage influent; 30% for both esp(fm) and esp(fs/fm) in septic waste; and 0% esp(fm) and 80% esp(fs/fm) in active pit toilets. The overall occurrence of the gene in animal feces was 7.7% (esp(fs/fm)) and 4.7% (esp(fm)); animal types with positive results included dogs (9/43, all esp(fm)), gulls (10/34, esp(fs/fm); 2/34, esp(fm)), mice (3/22, all esp(fs/fm)), and songbirds (5/55, all esp(fs/fm)). The esp gene was not detected in cat (0/34), deer (0/4), goose (0/18), or raccoon (0/23) feces. The inconsistent occurrence, especially in septic and pit toilet sewage, suggests a low statistical power of discrimination between animal and human sources, which means a large number of replicates should be collected. Both esp(fm) and esp(fs/fm) were common in raw sewage, but neither one efficiently differentiated between animal and other human sources.

Using the aquatic macrophyte Vallisneria americana (wild celery) as a nutrient bioindicator

Human sewage and septic waste are significant sources of nutrient loading to many aquatic ecosystems. Ecologically relevant nitrogen sources can be traced by analyzing nitrogen stable isotope ratios (δ15N signatures) in aquatic plants. Elevated δ15N signatures can suggest increased uptake of nitrogen derived from human and/or animal waste. In the current study, Vallisneria americana, a freshwater angiosperm, was collected from several locations in Upper Saranac Lake, NY, USA. Samples were also collected from Lake George, NY and the Sassafras River, MD, USA. Plant material was analyzed for δ15N and % N; some samples were also analyzed for δ13C, % C, and % P. Results suggest that there is variation in septic inputs to Upper Saranac Lake, with some areas of the lake receiving more input than others. Results also show that increased watershed population density is correlated with elevated δ15N signatures of Vallisneria americana. Taken together, these results suggest that nitrogen stable isotope analysis of aquatic plant tissue is an effective method for assessing and monitoring septic inputs to freshwater ecosystems.

Geochemical characteristics of trace elements in sediments of Dongting Lake, central China

water to this reservoir, and within the two reservoirs. Those isotopic measurements indicate the rapid change of natural sources of nitrate to one indicative of anthropogenic influences from inputs of animal manure and septic waste. Although the isotopic measurements suggest that animal and septic wastes are a primary source of nutrients, measurements of the ratio of nitrogen to phosphorus are more indicative of row cropping practices. Options for reduction of nutrient loads included changing the management practices of the aqua culture, installation of new sewage treatment systems, especially in the one major urbanized area of the upper watershed, and agricultural man.

The development of policy approaches for reducing nitrogen pollution to coastal waters of the USA

Two-thirds of the coastal rivers and bays in the United States are degraded from nutrient pollution, and nitrogen inputs these waters continue to increase. The nitrogen comes from a variety of sources, including runoff from agricultural fields, concentrated animal feeding operations, atmospheric deposition from fossil fuel combustion, and sewage and septic wastes. Technical solutions for nitrogen pollution exist at reasonable cost. That most of these solutions have not yet been implemented to any significant extent across the United States suggests that new policy approaches are necessary. The best solution may involve a combination of voluntary and mandatory approaches, applying different approaches to different sources of nitrogen pollution. A watershed-based approach that relies heavily on voluntary mechanisms (such as crop-yield insurance to reduce over-fertilization) is likely to be the most effective for some sources of nitrogen (such as runoff from agricultural fields), while a uniform national regulatory approach may be better for others (such as NO(x) emissions from fossil fuel combustion). Implementation of management strategies should be carefully coupled to monitoring programs to assess the effectiveness of these strategies. While both nitrogen and phosphorus are important to control, the focus should be on nitrogen management, in part because nitrogen is more generally the causal agent of coastal eutrophication. Also, while nitrogen-control practices tend to also reduce phosphorus pollution, phosphorus-control practices often have little effect on nitrogen. Although current scientific and technical knowledge is sufficient to begin to make substantial progress toward solving coastal nitrogen pollution, progress will be made more quickly and more cost effectively with increased investment in appropriate scientific research.

Use of tracers and isotopes to evaluate vulnerability of water in domestic wells to septic waste

AbstractIn Nebraska, a large number (&gt;200) of shallow sand‐point and cased wells completed in coarse alluvial sediments along rivers and lakes still are used to obtain drinking water for human consumption, even though construction of sand‐point wells for consumptive uses has been banned since 1987. The quality of water from shallow domestic wells potentially vulnerable to seepage from septic systems was evaluated by analyzing for the presence of tracers and multiple isotopes. Samples were collected from 26 sand‐point and perforated, cased domestic wells and were analyzed for bacteria, coliphages, nitrogen species, nitrogen and boron isotopes, dissolved organic carbon (DOC), prescription and nonprescription drugs, or organic waste water contaminants. At least 13 of the 26 domestic well samples showed some evidence of septic system effects based on the results of several tracers including DOC, coliphages, NH4+, NO3−, N2, δ15N[NO3−] and boron isotopes, and antibiotics and other drugs. Sand‐point wells within 30 m of a septic system and &lt;14 m deep in a shallow, thin aquifer had the most tracers detected and the highest values, indicating the greatest vulnerability to contamination from septic waste.

Evaluation of sewage sludge, septic waste and sludge compost applications to corn and forage: Ca, Mg, S, Fe, Mn, Cu, Zn and B content of crops and soils

This is the second of two papers presenting the data from an experiment on the application of aerobically-digested sewage sludge (AES), anaerobic lagoon septic wastes (ANS), sewage sludge compost and fertilizer to soils for grass forage and feed corn production at two different sites in Nova Scotia. Crop yields, plant tissue and Mehlich-1 extractable soil nutrients were evaluated; 15 elements were analyzed in the plant tissue and 9 elements in the soil extracts. This paper describes the Ca, Mg, S, Fe, Mn, Cu, Zn and B content of the crops and the Mehlich-1 extractable content of the soils. The response to the amendments was not consistent at the two sites with the two different crops. We found that the septic sludge (ANS) produced the highest forage Fe, Cu and Zn levels and was equal to compost in elevating corn stover and forage S and the forage B content. The compost produced the highest forage Ca and corn Zn, the AES produced the highest corn Mn, and fertilizer produced the highest forage Mn. None of the amendments produced excessive levels of the above nutrients; rather, the amendments improved the feed quality of the forage and corn stover. Lastly, it was noted that the Mehlich-1 extract only had a significantly positive correlation with forage Cu content.

Evaluation of sewage sludge, septic waste and sludge compost applications to corn and forage: yields and N, P and K content of crops and soils

This paper presents the data from two years of experiments concerned with the application of aerobically-digested sewage sludge, anaerobic lagoon septic sludge, sewage sludge compost or fertilizer to soils for grass forage and feed corn ( Zea mays L.) production at two different sites 45 km from Truro, Nova Scotia. Crop yields, plant tissue and Mehlich-1 extractable soil nutrients were evaluated; 15 elements were analyzed in the plant tissue and nine elements in the soil extracts. This paper describes the results of crop yields, plant N, P and K content and Mehlich-1 extractable P and K. The research demonstrated the fertilizer produced higher yields of grass forage than the sludge and the compost but equivalent to the sludge in corn yields. Forage and corn N, P and K contents, however, varied with treatment, crop and year, while the compost-amended soils were highest in extractable nutrients. Both sludges and the compost, therefore, could be effective sources of N, P and K for crop production. Compared to the conventional fertilizer, the nutrient availability from the organic amendments (especially N and P) was considerably lower than the 50% assumed at the start of the experiment; the sludges however, provided higher nutrient availability than the compost.

Modified Design Model for the Adsorption of Dye onto Peat

For over 20 years, peat has been recognized as a potential biosorbent for the treatment of wastewaters. Several studies have been reported in the literature including its use in cleaning oil spills 1 , the removal of heavy metals from wastewaters 2 , the removal of herbicides 3 , the treatment of slaughterhouse wastewaters, septic tank effiuents and dairy wastes 4 . The ability of peat to remove several dyes from aqueous effiuent was reported some time ago 5 . Further studies on single component adsorption of basic and acid dyes were carried out to study equilibrium isotherms 6 , diffusion based mass transport processes for batch and fixed bed systems 7 . Carbon has been used for acid dyes in fixed beds 8 . However, in these previous studies, conventional simplifi ed design methods—namely, bed depth service time (BDST) and empty bed residence time (EBRT) models—were applied to the experimental breakthrough curve data but failed to correlate these data due to the non-linearity of the BDST versus bed height data obtained. In the present paper new modifications have been developed based on an expression, N t / N 0 = 1 – exp(– a * sqrt ( t )), where N t , N 0 , a, t represent the bedcapacity at service time t, the saturated bed capacity found in isotherm experiments, a rate constant and the service time of the bed respectively. The expression correlates the residence time in the adsorption bed with the time dependent fraction degree of saturation of the bed. It enables modified BDST and EBRT models to be applied and correlate the experimental data very accurately. This model is particularly suited to predicting the performance of fixed bed adsorbers, when the system requires a long time to reach equilibrium or when several fixed bed adsorbers are used in series.

Application of Electromagnetic Logging to Contamination Investigations in Glacial Sand‐and‐Gravel Aquifers

AbstractElectromagnetic (EM) logging provides an efficient method for high‐resolution, vertical delineation of electrically conductive contamination in glacial sand‐and‐gravel aquifers. LM. gamma, and lithologic logs and specific conductance data from sand‐and‐gravel aquifers at five sites in the northeastern United States were analyzed to define the relation of KM conductivity to aquifer lithology and water quality. Municipal waste disposal, septic waste discharge, or highway deicing salt application at these sites has caused contaminant plumes in which the dissolved solids concentration and specific conductance of ground water exceed background levels by as much as 10 to 20 limes.The major hydrogeologic factors that affected KM log response at the five sites were the dissolved solids concentration of the ground water and the silt and clay content in the aquifer. KM conductivity of sand and gravel with uncontaminated water ranged from less than 5 to about 10 millisiemens per meter (mS/m); that of silt and clay zones ranged from about 15 to 45 mS/m: and that of the more highly contaminated zones in sand and gravel ranged from about 10 to more than 80 mS/m. Specific conductance of water samples from screened intervals in sand and gravel at selected monitoring well installations was significantly correlated with KM conductivity.CM logging can be used in glacial sand‐and‐gravel aquifer investigations to (1) determine optimum depths for the placement of monitoring well screens: (2) provide a nearly continuous vertical profile of specific conductance to complement depth‐specific water quality samples; and (3) identify temporal changes in water quality through sequential logging. Detailed lithologic or gamma logs, preferably both, need to be collected along with the F.M logs to define zones in which elevated EM conductivity is caused by the presence of sill and clay beds rather than contamination.

NONPOINT POLLUTION CONTROL STRATEGIES FOR MOSES LAKE, WASHINGTON

ABSTRACT Nutrient sources influencing eutrophication of Moses Lake, Wash., have been evaluated in a multistage investigation of urban and agricultural land uses in the watershed. Nutrient loadings from surface and groundwater contributions were quantified in a year-long monitoring program. Subsequent studies have assessed effectiveness of various control techniques to reduce nutrient input to the lake. These recent (1984) investigations include full-scale field demonstrations of agricultural irrigation practices involving cablegation, wheel line, and center pivot systems monitoring nutrient and water movement through coarse native soils. Over 75 percent of local farmers are trying control measures under a unique agricultural cost-sharing program. Other nutrient sources and controls evaluated and ranked for nutrient removal effectiveness include shallow detention ponds to enhance nutrient trapping, local septic tank management policies, animal waste and fish hatchery controls, and miscellaneous in-lake imp...