Etiket Arşivleri: Alkalinity

Water Hardness and Alkalinity

Water Hardness and Alkalinity
It may be that your water hardness and alkalinity are perfect for discus but unfortunately this is not always the case. It is far easier to adjust hardness and alkalinity upwards as when keeping hard-water fishes, but lowering these values is by no means impossible. It simply involves another step in the water conditioning process. Total hardness (general hardness) is the sum combination of carbonate and noncarbonate hardness of your water. Total hardness is measured as, degrees, dH, or ppm (parts per million). One dH is 17.9 ppm. How total hardness is expressed depends upon the author and his orientation. I prefer dH simply because as a discuskeeper, I like to see smaller numbers when I am measuring water hardness! If I were keeping African cichlids I might prefer to measure my water’s hardness in ppm. Total hardness is usually not a big issue in keeping discus; alkalinity is a far more important factor in the breeding of discus. Alkalinity is sometimes referred to as carbonate hardness(KH)or buffering capacity. Alkalinity is the important factor in breeding discus and controlling the pH of the water. Alkalinity refers to the level of calcium, carbonate and bicarbonate in the water. It is measured in KH or mg/L CaCo3 or parts per million. One milligram per liter (mg/L) is the equivalent of one part per million. Soft water is 3dH and 0 to 50 mg/L CaCo3; medium soft water is 3 to 6 dH and 50 to 100 mg/L CaCo3; slightly hard water is 6 to 12 dH and 100 to 200 mg/L CaCo3; moderately hard water is 12 to 18 dH and 200 to 300 mg/L CaCo3; hard water is over 18 dH and over 300 mg/L CaCo3. The values for general hardness and alkalinity given above do not always match each other. It is entirely possible to have a higher reading of general hardness and a lower reading of alkalinity. The lower reading for alkalinity is the more desirable for discus water. Discus will do quite well in slightly to moderately hard water. In fact, many breeders routinely keep their fish in these values to ensure proper development of the young fish, but for development of the eggs, soft to moderately soft water, particularly concerning alkalinity is critical. Therefore, it is not necessary to drastically adjust the general hardness or alkalinity when you first start to keep discus unless the values are very high.

Analysis of Water Chemistry

Analysis of Water Chemistry

  • Urban Stream Restoration Project

  • Outline

  • Water Chemistry Background

  • Chemistry in Urban Streams

  • Methods

  • 2003 Results

  • Comparison to 2002

  • Conclusions

  • Outline

  • Water Chemistry Background

  • Chemistry in Urban Streams

  • Methods

  • 2003 Results

  • Comparison to 2002

  • Conclusions

  • Temperature

  • Most aquatic organisms are cold-blooded and have an ideal temperature range, specific to the organism:

  • Diatoms 15-25 degrees C

  • Green algae 25-35 degrees C

  • Blue greens 30-40 degrees C

  • Salmonids – cold water fish

  • Temperature, continued

  • Affects development of invertebrates, metabolism of organisms

  • Affects dissolved oxygen (warm water holds less oxygen)

  • Warm water makes some substances more toxic (cyanide, phenol, xylene, zinc) and, if combined with low DO, they become even more toxic

  • Dissolved Oxygen

  • Oxygen that is dissolved in water

  • DO increases with cooler water and mixing of water through riffles, storms, wind

  • Nutrient loading can lead to algal blooms which result in decreased DO

  • 4-5 ppm DO is the minimum that will support large, diverse fish populations. Ideal DO is 9 ppm. Below 3 ppm, all fish die.

  • Dissolved Oxygen, continued

  • Dissolved oxygen can also be expressed as % saturation

  • 80-124% = excellent

  • 60-79% = ok

  • < 60% = poor

  • Conductivity

  • Measures the ability of water to carry an electric current

  • Measures the ions such as Na+, Cl- in the water

  • Differences in conductivity are usually due to the concentration of charged ions in solution (and ionic composition, temp.)

  • Reported as microsiemens per cm

  • pH

  • pH measures the degree of acidity or alkalinity of the water (each number is a 10-fold difference)

  • 0-6 = acid; 7 = neutral; 8-14 = base

  • Ideal for fish = 6.5 –8.2

  • Ideal for algae = 7.5 – 8.4

  • Acid waters make toxic chemicals (Al, Pb, Hg) more toxic than normal, and alter trophic structure (few plants, algae)

  • Turbidity

  • Measures the cloudiness of the water

  • Turbidity caused by plankton, chemicals, silt, etc.

  • Most common causes of excess turbidity are plankton and soil erosion (due to logging, mining, farming, construction)

  • Turbidity, continued

  • Excess Turbidity can be a problem:

  • Light can’t penetrate through the water – photosynthesis may be reduced or even stop – algae can die

  • Turbidity can clog gills of fish and shellfish –can be fatal

  • Fish cannot see to find food, but can hide better from predators

  • Phosphorus (Reactive)

  • Is necessary for plant and animal growth

  • Natural source = phosphate-containing rocks

  • Anthropogenic source = fertilizer and pesticide runoff from farming

  • Can stimulate algal growth/bloom

  • Nitrates

  • Formed by the process of nitrification (addition of O2 to NH3 by bacteria)

  • Used by plants and algae

  • Is mildly toxic, fatal at high doses

  • Large amounts (leaking sewer pipes, fertilizer runoff, etc.) can lead to algal blooms, which can alter community structure, trophic interactions and DO regimes)

  • Below 90 mg/L seems to have no effect on warm water fish, but cold water fish are sensitive

  • Alkalinity

  • A measure of the substances in water that can neutralize acid and resist changes in pH

  • Natural source = rocks

  • Ideal water for fish and aquatic organisms has a total alkalinity of 100-120 mg/L

  • Groundwater has higher alkalinity than surface water

  • Hardness

  • The amount of Calcium and Magnesium in the water (the two minerals mostly responsible)

  • Natural source = rocks

  • Limestone = hard water, granite = not hard water

  • Hardness, continued

  • Soft water can be a problem: in soft water, heavy metals are more poisonous, some chemicals are more toxic, drinking soft water over long periods can increase chance of heart attack

  • 0 – 60 = soft water

  • 61-120 = moderately hard water

  • 121-180 = hard water

  • 181+ = very hard water

  • Hardness and alkalinity are related

  • Outline

  • Water Chemistry Background

  • Chemistry in Urban Streams

  • Methods

  • 2003 Results

  • Comparison to 2002

  • Conclusions

  • Physical Effects of Urbanization Related to Water Chemistry

  • Riparian Vegetation Removal

  • Decreased Groundwater Recharge

  • Heat Island Effect

  • Increased Surface Runoff / Impervious Surfaces

  • Leaky Storm-water / Sewage Pipes

  • Point Source Pollution

  • Trends in Water Chemistry

  • Temperature increases

  • Nitrate increases

  • Phosphorus increases

  • Conductivity increases (Increased ion concentration)

  • O2 demand increases

  • Outline

  • Water Chemistry Background

  • Chemistry in Urban Streams

  • Methods

  • 2003 Results

  • Comparison to 2002

  • Conclusions

  • Field Measurements

  • Dissolved Oxygen

  • Temperature

  • Conductivity

  • pH

  • Water Collection For Laboratory Analysis

  • Grab Samples

  • Three replicates (from multiple samples)

  • Measured within 24 hours (few exceptions)

  • Laboratory Analysis

  • Nitrate

  • Reactive

Phosphorus

  • Alkalinity

  • Hardness

  • Turbidity

  • Outline

  • Chemistry in Urban Streams

  • Water Chemistry Measurements and Theory

  • Methods

  • 2003 Results

  • Comparison to 2002

  • Conclusions

  • Field Measurements 2003

  • Turbidity

  • All values for 2003 <5 jtu

  • For 2002, all but one sampling date <5 jtu

  • The one date for 2002 >5 was during a storm event

  • Reactive Phosphorus 2003

  • Nitrate 2003

  • Alkalinity 2003

  • Hardness 2003

  • Outline

  • Chemistry in Urban Streams

  • Water Chemistry Measurements and Theory

  • Methods

  • 2003 Results

  • Comparison to 2002

  • Conclusions

  • Field Measurement PB

  • Field Measurement For SAL

  • Paint Branch

  • Stewart April Lane

  • Outline

  • Chemistry in Urban Streams

  • Water Chemistry Measurements and Theory

  • Methods

  • 2003 Results

  • Comparison to 2002

  • Conclusions

Between Site Differences

  • Land use – increased runoff cause increased input of particular constituents

  • Natural site variation – Substrate type

Between Years

  • Increased snow caused more runoff increased use of road-salt

  • Drought (temperature, DO)

“. . . Rivers and the inhabitants of the watery element were made for wise men to contemplate, and fools to pass by without consideration, . . . for you may note, that the waters are Nature’s storehouse, in which she locks up her wonders.”

  Izaak Walton

  (from Ward, 1992)

Experiment-4

FE 211 25.10.2004

EXPERIMENT 4

LAB REPORT

Submitted By : Mutlu DEMİREL Group: 3

MATERIALS:

HCl , HAc , Phenolphthalein , Methyl Orange , NaOh , Dilute Water ,Buret ,

Erlenmayer Flask ,

PURPOSE:

In this experiment we titrated HCI and HAc mixture with NaOH to determine amounth of HCI , HAc and NaOH and the molarity of NaOH.

METHOD:

Gravimetric Analysis

THEORY:

The capacity of water to accept protons is called alkalinity. Alkalinity is important in water treatment and in the chemistry and biology of natural waters. Alkalinity serves as a pH buffer and reservoir for inorganic carbon. It helps to determine the ability of water to support algal growth and other aquatic life; thus, it can be used as a measure of water fertility. In natural waters, the species responsible for alkalinity are OH-, HCO3-, and CO32-. Alkalinity is equal to [OH-] + [HCO3-] + 2[CO32-]. The coefficient of “2” before [CO32-] is necessary because carbonate accepts two protons. However, in natural waters of pH from 7 – 9, the predominant species is bicarbonate.

Alkalinity can be measure by titration with a standard solution of HCl. The titration reaction for the bicarbonate ion is: HCO3- + H+ _ H2CO3 The endpoint can be determined with the methyl orange indicator or by measuring the pH of the solution throughout the titration. In the later case, analysis of the titration curve allows determination of the end point. Alkalinity is expressed as the number of moles of H+ required to titrate one liter of water sample or as mg CaCO3/L of water.

PROCEDURE:

5 ml HCI and 5 ml HAc was poured into a erlenmayer flask. Then 2-3 drops of methyl orange indicator was added to this solution and titrated with standart solution until the color of the solution change. Then 2-3 drops of phenolphthalein was added to the solution and again titrated with NaOH until the end point was observed.

RESULTS AND CALCULATION :

HCI = n NaOH fw of HCI = 36.5 g volume of NaOH = 8 mL

NaOH =

NaOH = n HCI = 0.0008 mol

fw of

volume of NaOH = 11 mL

NaOH = n

NaOH =

NaOH = n = 0.0011 mol

DISCUSSION:

In this titration reaction we have a mixture of strong acid , HCI , and weak acid HAc , as primary solution. The mixture of acids were titrated with base , NaOh because the Ka for weak acid was abouth or less so two end point was observed. The first end point was for HCI , the second was for HAc . To observe the end points of this two different acids, two different indicators were used. Methyl orange for HCI and Phenolphthalein for HAc.