Showing papers on "Water quality published in 1985"

Water supply and pollution control

Abstract: Water management - institutions and technology water management - environmental considerations water use and wastewater generation the availability of water water quanitity water quality hydrology and water management surface-water supplies reservoirs groundwater conveying and distributing water types of aqueducts hydraulic considerations design considerations distribution systems pumping wastewater and stormwater systems design of sanitary sewers design of storm drainage systems water quality microbiological quality chemical quality of drinking water quality criteria for surface waters selected pollution parameters systems for treating wastewater and water wastewater treatment systems water treatment systems physical treatment processes flow-measuring devices screening devices hydraulic characteristics of reactors mixing and flocculation sedimentation filtration chemical treatment processes chemical considerations water softening iron and manganese removal chemical disinfection and by-product formations disinfection of potable water disinfection of wastewater taste and odour fluoridation corrosion and corrosion control reduction and dissolved salts nitrate removal volatile organic chemical removal synthetic organic chemical removal biological treatment processes biological considerations characteristics of wastewater trickling (biological) filters rotating biological contractors activated sludge stabilization ponds odour control individual on-site wastewater disposal marine wastewater disposal processing of sludges sources, characteristics, and quantities of waste sludges arrangement of unit processes in sludge disposal gravity thickening flotation thickening biological sludge digestion vacuum filtration pressure filtration centrifugation recovery of chemicals ultimate disposal advanced wastewater treatment processes limitations of secondary treatment selection of advanced wastewater treatment processes suspended-solids removal carbon adsorption phosphorous removal nitrogen removal wastewater reclamation water-quality models.

Water Treatment Principles and Design

Abstract: Physical and Chemical Quality. Microbiological Quality. Water Quality Criteria and Standards. Principles of Process Engineering. Precipitation, Coagulation, Flocculation. Gravity Separation. Filtration. Adsorption. Ion Exchange and Demineralization. Gas Transfer. Disinfection. Residuals Management. Water Reuse. Inorganics. Organics. Taste and Odor. Corrosion. Predesign. Plant Siting. Facilities Design. Special Plant Hydraulic Topics. Process Control. Operation and Maintenance. Construction and Operating Cost Estimating. Index.

Modeling the Effects of Acid Deposition: Estimation of Long‐Term Water Quality Responses in a Small Forested Catchment

Abstract: Research in recent years has led to conceptualizations of the long-term responses of catchment surface water quality to acidic deposition. That research has focused attention on certain soil processes as likely keys to catchment responses (anion retention, cation exchange, primary mineral weathering, aluminum dissolution, and CO2 solubility). We present a mathematical model which uses quantitative descriptions of these soil chemical processes to estimate the long-term chemical changes that occur in the soil, soil water, and surface waters of catchments in response to changes in atmospheric deposition. The model is applied to a small forested catchment in the Shenandoah National Park, Virginia. Historical changes in surface water quality are reconstructed for the catchment for the last 140 years. The model indicates that alkalinity of surface waters in the catchment may have been reduced by as much as 50%. Water quality is forecast for the catchment under three different scenarios of future changes in atmospheric deposition. The model indicates that all but very large reductions in deposition will result in further deterioration of the catchment water quality. The process-oriented, lumped-parameter approach used is consistent with all currently available observations of water quality in the catchment. Due to the lack of long-term records of catchment water quality, strict verification of the model estimates and an assessment of the model validity is problematic. This is the case for all models of long-terrn catchment chemical responses to acid deposition. Nonetheless, the model provides a means of integrating the results of individual process level laboratory and field studies. Used this way, the model becomes a vehicle for examining the interactions and long-term implications of our conceptualization of the acidification process.

Irrigation water quality criteria

Abstract: This chapter focuses on how to evaluate the chemical quality of treated wastewater for use in irrigating plants. The quality of treated municipal wastewater depends to a great extent on the quality of the municipal water supply, nature of the wastes added during use, and the degree of treatment the wastewater has received. There are no specific requirements in California on the frequency of sampling reclaimed wastewater used for irrigation. The primary factor in evaluating water quality for irrigation is the quantity and kind of salt present in the water supplies. As salinity increases in the reclaimed wastewater used for irrigation, the probability for certain soil, water, and cropping problems increases. Salinity, measured by electrical conductivity, is the single most important parameter in determining the suitability of water for irrigation. Occasional problems of abnormal pH, corrosion of pipelines and equipment, irrigation water system clogging and high residual chlorine occur when using reclaimed wastewater is used.

Water Quality Management in Aquaculture

Abstract: Water quality includes all physical, chemical and biological factors that influence the beneficial use of water. Where fish culture is concerned, any characteristic of water that affects the survival, reproduction, growth, production, or management of fish in any way is a water quality variable. Obviously, there are many water quality variables in pond fish culture. Fortunately, only a few of these normally play an important role. These are the variables that fish culturist should concentrate on, and attempt to control to some extent by management techniques.

Stream, lake, estuary, and ocean pollution

Abstract: Biological aspects of stream pollution. Hydrological considerations in stream analysis. Biochemical factors involved in stream analysis. Mathematics involved in predicting stream pollutant deoxygenation rates. Stream reaeration. Stream oxygen sag analysis. Receiving water quality objectives. Estuarine analysis. River basin administration stream studies - illustrative complete case. Lakes. Coastal area characteristics and pollution. Models for receiving water quality. Summary. Appendices.

Water quality : characteristics, modeling, modification

Abstract: 1. Sources and Uses of Water. 2. Physical, Chemical, and Biological Characteristics of Water. 3. Significance of the Characteristics of Water. 4. Water Quality: Standards and Global Perspectives. 5. Stoichiometry, Reaction Kinetics, and Materials Balances. 6. Mathematical Models of Physical Systems. 7. Movement of Contaminants in the Environment. 8. Water Quality in Rivers and Estuaries and Near Ocean Outfalls. 9. Water Quality in Lakes and Reservoirs. 10. Water Quality in Groundwater Systems. 11. Introduction to Water and Wastewater Treatment. 12. Physical Treatment Methods. 13. Chemical Treatment Methods. 14. Biological Treatment Methods. 15. Synthesizing Water and Wastewater Treatment Systems.

Ground water quality

Abstract: This book covers the sources, types, and quantities of contaminants in ground water, methods for ground water quality research, subsurface characterization in relation to ground water pollution, and transport and fate of subsurface contaminants. It focuses on the scientific and technological challenges and accomplishments in ground water quality research and assesses the state-of-the-art developments in this area on an international scale.

Particles, Pretreatment, and Performance in Water Filtration

Abstract: Relationships among raw water quality, pretreatment facilities, and the design of packed bed filters are presented and applied. The particle size, particle concentration, particle surface characteristics, and solution chemistry in the raw water supply have important and predictable effects on filter design. An integrative approach to water treatment plant design, from raw water quality to filter bed performance, will facilitate process evaluation and has the potential for providing a basis for optimal plant design.

Water-quality assessment: a screening procedure for toxic and conventional pollutants in surface and ground water. Part 2, (revised 1985)

Abstract: New technical developments in the field of water quality assessment and a reordering of water quality priorities prompted a revision of the first two editions of this manual. The utility of the revised manual is enhanced by the inclusion of methods to predict the transport and fate of toxic chemicals in ground water, and by methods to predict the fate of metals in rivers. In addition, major revisions were completed on Chapter 2 (organic toxicants), Chapter 3 (waste loadings), and Chapter 5 (impoundments) that reflect recent advancements in these fields. Applying the manual's simple techniques, the user is now capable of assessing the loading and fate of conventional pollutants (temperature, biochemical oxygen demand-dissolved oxygen, nutrients, and sediments) and toxic pollutants (from the U.S. EPA list of priority pollutants) in streams, impoundments, estuaries, and ground waters. The techniques are readily programmed on hand-held calculators or microcomputers. Most of the data required for using these procedures are contained in the manual.

Feasibility and efficacy of in-home water chlorination in rural North-eastern Brazil.

Abstract: The purpose of this study was to assess the feasibility, acceptability and effect of an in-home water chlorination programme in a rural village. Previous studies at this site showed high levels of faecal coliforms in household water, high diarrhoea rates in children, and enterotoxigenic Escherichia coli and rotaviruses were the most common pathogens isolated from patients. Household water came from a pond and was stored in clay pots. No homes had sanitary facilities. A blind, cross-over trial of treatment of household water with inexpensive hypochlorite by a community health worker was carried out over 18 weeks among 20 families. Water in the clay pots was sampled serially, and symptom surveillance was done by medical students. The programme was generally acceptable to the villagers and no change in water use patterns were apparent. The mean faecal coliform level in the chlorinated water was significantly less than in the placebo treated samples (70 vs 16000 organisms/dl, P less than 0.001). People living in houses receiving placebo treatment had a mean of 11.2 days of diarrhoea per year, and the highest rate of 36.7 was among children less than 2 years old. Diarrhoea rates were not significantly different among the participants while exposed to water treated with hypochlorite. We conclude that a low-cost programme of this type, which utilizes community resources, is logistically feasible, appears to be culturally acceptable in this setting, and can result in a marked reduction in water contamination. The lack of effect on diarrhoea rates suggests that improvement in water quality may affect morbidity only when other variables relating to faecal-oral agent transmission are ameliorated at the same time.

Buffer strip management in forest operations: a review

Abstract: Summary Buffer strips form an integral part of contemporary forest management practices for stream protection and maintenance of water quality by providing an opportunity for detention of sediment-contaminated water orginating from roads and forest harvesting areas. Formulae devised for making the required recommendations for stream protection areas can only provide a guide to the catchment manager. The most commonly recommended width for stream buffers is 30 m. However, this width should increase with increasing site limitations. Buffers should extend to the runoff confluence point or spring-head of any sub-catchment. The costs associated with the provision of stream protection areas are significant and must be weighed against cost of water treatment and other costs to the community. The provision of stream buffers in catchment areas allows the optimal use of the land for timber and water production.

Regional water quality impacts of intensive row-crop agriculture: A Lake Erie Basin case study

Abstract: Intensive row-crop agriculture dominates land use in the northwestern Ohio River basins draining into Lake Erie. Detailed, longterm studies of water quality in these rivers reveal high unit-area P loads entering Lake Erie, even though gross erosion rates are relatively low. Concentrations of nitrate-N and currently used herbicides are also high from May through July, both in surface waters and in public water supplies derived therefrom. To reduce P loading to Lake Erie, water quality management agencies are advocating adoption of conservation tillage. Conservation tillage could increase nitrate and herbicide contamination of area waters. This region9s detailed baseline nutrient and herbicide data provide an opportunity to evaluate the effects of conservation tillage on a variety of water quality parameters. To separate weather-related from management-related effects, an ecosystem approach is advocated.

Sediments and water quality

Abstract: Sediments play a crucial role in water quality. On the one hand they remove pollutants from the water column whereas on the other hand pollutants accumulated in the sediments may provide the surface water (long after the source of pollution has ceased) with contaminants. An overview of the immobilization and remobilization processes affecting heavy metals and organic micro‐pollutants is given.

Remote sensing of water quality in the Neuse River Estuary, North Carolina

Abstract: Les parametres etudies comprennent la salinite, la chlorophylle a, la turbidite et les solides totaux en suspension

Stream-watershed relations in the Missouri Ozark Plateau Province

Abstract: Impact des pratiques d'occupation des sols (zone urbaine, pâture et foret) ainsi que des facteurs edaphiques (geologie, type de sol) sur la chimie de l'eau et les concentrations de chlorophylle dans les cours d'eau

Predictive models for the biomass of blue-green algae in lakes

Abstract: In lakes which experience water quality problems due to the nuisance growth of blue-green algae, summer concentrations of chlorophyll a may not always be a meaningful measure of water quality for making management decisions. Models for the prediction of summer mean blue-green algal biomass were thus developed from data collected from five systems located in North America and Sweden. It is suggested that the model of choice is log BG =−0.142 + 0.596 log TP – 0.963 log Z, where BG is the biomass of blue-green algae (g m−3), TP is the concentration of total phosphorus (mg m−3), and Z is the mean depth of the lake (m). When coupled to current loading models, this model can potentially be used to assess the impacts of phosphorus loading reductions on threshold odor in water supplies.

Drip irrigation of cotton with saline-sodic water

Abstract: A two-year study was conducted in the Negev region of Israel, using the drip method, to determine the effect of four levels of water quality (EC =1.0, 3.2, 5.4 and 7.3 dS/m) in combination with three soil amendment treatments (gypsum spread on the soil surface along the drip laterals after planting, injection of H2SO4 into the water during each irrigation, and a control) on plant response, salt distribution in the soil profile, and soil sodification processes. Salinity did not reduce yields even at the highest level, in spite of sodium and chloride accumulation. The highest seed cotton yield (6.4 t/ha) was obtained with the local well water (EC =3.2 dS/m), indicating an optimal response to salinity. The addition of soil amendments during the irrigation season, although reducing exchangeable sodium accumulation near the emitter, endangers the next crop by increasing sodium accumulation under the plant row. It is therefore, recommended that the amendment be applied only before the winter.

Bacterial Colonization of Point-of-Use Water Treatment Devices

Abstract: Point-of-use water treatment devices were investigated to identify organisms that may colonize these filters, to determine the magnitude of the postcolonization release of microorganisms into the product water during daily use or after periods of nonuse, and to demonstrate the effect of tap water of marginal bacteriological quality on the quality of the product water. The bacterial count was found to vary between units of different design, between units of the same design, and between water samples from the same filter unit collected at different times of the day; it was affected by the length of time the filter cartridge had been in use, the design of the cartridge, and the temperature of the water, as well as by the species of microorganism. Installation and use by the public of in-the-home, point-of-use water treatment devices have increased in the United States during the last several years. This trend has paralleled increased consumer awareness of the potential health risks posed by some community drinking water systems. Interest in these point-of-use devices is usually based on a desire to improve the aesthetic quality of drinking water, including a reduction of thecontaminants that cause taste and odor, turbidity, hardness. and other undesirable effects. Manufacturers of point-of-use water treatment devices have estimated that some 6 million families already use their products and that the market is increasing. A study of the designs of commercially available point-of-use devices indicates that granular activated carbon (GAC) is often the major component for treatment; other components include ion exchange resins, spirally wound acrylicfilament spools, controlled-pore-size membranes for reverse osmosis systems, and paper filters. The quantity of activated carbon ranges from 30 g in a faucetmounted device to 266-593 g in the larger cartridges. Some designs precoat the carbon on a fibrous fluted material or press the carbon into a dense core rather than packing the cartridge bed

Sediment and Nutrient Export in Runoff from Burned and Harvested Pine Watersheds in the South Carolina Piedmont

Abstract: Soil and nutrient export in ephemeral flow were studied over a 3-yr period following clearcutting three loblolly pine (Pinus taeda L.) watersheds (0.60–1.24 ha). Two preharvest, low-intensity prescribed fires had no effect on flow or water quality. Harvesting after the third prescribed fire significantly increased sediment concentration and export, but increases were minor compared with sediment export reported for mechanical site preparation. Nutrient concentrations varied among watershed locations because of differences in surface soil depth, but were generally unaffected by harvest. Because harvest increased runoff, nutrient export (concentration × flow) was generally increased. Results of this study show that loblolly pine stands in the erosive Piedmont physiographic region can be harvested following a series of low-intensity prescribed fires with minimal soil loss or degradation of water quality.

Water Quality and Its Control

Abstract: Introduction Some Important Characteristics of Water Some Concepts of Aquatic Biology Characteristics and Availability of Water Resources Water Uses Methods of Evaluating Water Quality Constituents in Natural Waters Types and Causes of Water Quality Problems Water and Health Oxygen Balance in Streams Municipal Water Systems Municipal Wastewater Systems Industrial Water and Wastewater Standards Used in Water Quality Control Regulation of Water Quality Progress, Problems and Prospects Appendix Index.

Policies for nonpoint-source water pollution control

Abstract: POINT-SOURCE water pollution controls alone are insufficient to meet the objectives of the Clean Water Act. Agricultural and urban non-point sources account for more than half of the biological oxygen demand (BOD5), nearly all the suspended solids, and in some regions, most of the phosphorus, nitrogen, and many toxics discharged into water-ways ( 6 ). Despite its importance, nonpoint-source pollution continues largely unregulated. This is in stark contrast to the attention paid to point sources. For municipal sewage treatment plants alone, federal outlays were authorized at $2.4 billion per year for fiscal years 1984 and 1985. By comparison, funds for cost-sharing and subsidy programs that can reduce agricultural water pollution are minuscule, and most of the programs are directed more at slowing soil erosion than improving water quality. Section 208 of the Clean Water Act, which requires states to develop nonpoint-source plans, has not resulted in significant water quality improvements either. Although 20 states and the District of Columbia have erosion and sediment control laws directed at urban nonpoint sources, these sources nevertheless continue to be a major source of water pollution. The failure of existing policies to reduce nonpoint pollution, together with the …

Empirical Methods for Predicting Eutrophication in Impoundments. Report 3. Phase II. Model Refinements.

Abstract: : Empirical eutrophication models are useful tools for some aspects of reservoir water quality assessment and management. This report modifies existing model structures and parameter estimates to improve their generality and permit application under a wider spectrum of reservoir conditions. A network of models is assembled for predicting reservoir-average concentrations of total phosphorus, total nitrogen, chlorophyll-a, transparency, organic nitrogen, particulate phosphorus, and hypolimnetic oxygen depletion rate (near-dam) as functions of reservoir mean depth, hydraulic residence time, and inflow concentrations of total phosphorus, ortho-phosphorus, total nitrogen, and inorganic nitrogen. Models are tested against several independent lake and reservoir data sets compiled from the literature. An error analysis indicates that the prediction of chlorophyll-a, the most direct measure of eutrophication response, is limited more by variabilities in the biological responses to a given set of nutrient concentrations and other environmental conditions than by uncertainties in predicting pool nutrient levels from external loadings. Inflow available phosphorus concentration and mena depth are shown to explain most of the variance in reservoir tropic state indicators and hypolimnetic oxygen status. Keywords include: Eutrophication; Reservoirs; Reservoir operation; Water quality--measurement; Water quality management.

Bacterial Quality of Runoff from Manured and Non-Manured Cropland

Abstract: INDICATOR bacteria concentrations in non-snowmelt runoff from adjacent manured and non-manured watersheds were monitored for 4 years. Significant differences in the quality of runoff from the manured and non-manured cropland were not consistently observed. Hydrological conditions greatly affected bacterial concentrations. Heavy runoff under wet weather conditions resulted in water quality degradation irrespective of cropping or manuring activity. Under relatively dry weather conditions, runoff from both the manured and non-manured cropland often met the recommended bacterial quality criteria for water to be used for recreation or as a source of public water supplies. The relatively better quality of manured cropland runoff in our study compared to other studies was attributed mainly to the management practice of dry weather manure application followed by immediate plowdown and the mostly level topography of the watersheds. Much lower indicator bacteria concentrations in long-term stored manure than in relatively fresh manure suggested a lower potential for runoff pollution from land application of the former.

Expression for Drinking Water Supply Standards

Abstract: Various authorities and regulating agencies have set standards for deciding the suitability of a water for drinking purposes. These standards prescribe the permissible concentrations of quality variables. When some variables exceed the permissible levels, a decision for permitting further use of the water supply has to be based on the importance of those variables with exceeded concentrations. It is proposed that standards for a drinking water supply should be set through a single number representing the integrated effect of all the variables, keeping due regard to the importance of each variable. Such an integrated water quality index (WQI) would help in decision making. Models and curves have been presented to evolve a WQI for drinking water supplies. It is suggested that water with a WQI lower than 90 should not be permitted. The acceptable quality therefore, should be in the 90–100 range of the WQI.

Mortality of Striped Bass Larvae in Relation to Contaminants and Water Quality in a Chesapeake Bay Tributary

Abstract: Numerous factors have been implicated in the decline of striped bass Morone saxatilis along the east coast of the United States. This study was designed to evaluate the effects of contaminants and water quality on survival of striped bass larvae in a natural spawning habitat (Nanticoke River, Maryland). Larvae were tested in chambers submerged in the river. Organic and inorganic contaminants and water quality variables were monitored to correlate survival of larvae with habitat quality. In two 96-h experiments at three river stations, 90–99% of larvae died whereas control mortality was only 15–25%; the differences were significant. None of the 69 organic contaminants specifically analyzed were detected in river water and can be eliminated as causes of larval mortality. Of the eight metals analyzed, seven never exceeded 50 μg/L in river water, but total aluminum concentrations were 480–4,100 μg/L (39–181 μg/L filtered sample). Factors suspected as contributors to mortality were low pH (6.0–6.8), h...

Headwater Stream Losses of Nitrogen from Two Coastal Plain Watersheds

Abstract: Nitrogen concentrations and water flow were measured for a 3-yr period from two watersheds of the Atlantic Coastal Plain in North Carolina to assess sinks for NO₃-N₄ Both of the areas are typical of the largest agricultural producing area in the region. From the Middle Coastal Plain watershed with 1299 ha of predominantly well- to moderately well-drained soils, the losses of NO₃-N and total N in surface drainage water were 2.5 and 4.5 kg ha⁻¹ yr⁻¹, respectively. The Lower Coastal Plain watershed with 6998 ha of somewhat poorly- to poorly-drained soils had NO₃-N and total N losses of 0.5 and 2.5 kg ha⁻¹ yr⁻¹, respectively. These values were much lower than expected based on agricultural production, fertilizer used, and crop efficiency. The soils included in the study were Typic Paleudults to Aquic Paleudults and Aquic Hapludults to Aeric Paleaquults. Denitrification between the field and stream was concluded to be the primary reason for these low values. However, the concentrations of NO₃-N in streams near the field outlets decreased significantly as N enriched water moved through the transport system. The lowest stream elevations sampled on the Middle and Lower Coastal Plain watersheds averaged 0.6 and < 0.1 mg L⁻¹ NO₃-N with maximum values of 2.5 and 0.6 mg L⁻¹, respectively. Comparing changes in nitrate and chloride concentrations and the reducing Eh in the stream and floodplain sediments suggest denitrification as the loss mechanism in the stream transport system. Ostensibly the stream is responsible for the loss rather than the riparian area; however, the area inundated by the stream is small compared to the flood plain. The Middle and Lower Coastal Plain watersheds have 2.5 and 94 ha inundated by the stream while confined to the channel, but while in a moderate flood these values increase to 20 and 250 ha, respectively. While instream losses of NO₃-N are important in this region to maintain water quality, they are not sufficient to completely counter heavy loading by nonpoint sources.