Physical, Chemical And Biological Characteristics Of Wastewater 47701z

INTRODUCTION: WW CONSTITUENTS AND REGULATIONS

THE HYDROLOGIC CYCLE AND WATER QUALITY • Water - cover ¾ of the earth surface • Over 97% of the total water is not readily usable – oceans and other saline bodies of water • Over 2% is inaccessible – ice caps and glaciers, atmospheric and soil moisture • Only 0.62% for human – fresh water lakes, rivers & groundwater supplies

HYDROLOGIC CYCLE Atmosphere Condensation

Evaporation

Evapotranspiration

Earth’s surface

Surface runoff Percolation

Ground water flow

IMPURITIES IN WATER 1. Surface, or nuclei during condensation 2. Liquid water travels through the remainder of the hydrologic cycle – with other material in air or earth 3. Human activities – industrial and domestic waste * Impurities can be both in suspended and dissolved form

WATER QUALITY • Predicted on the intended use of the water • Water pollution – defined as the presence in water of impurities in such quantity and of such nature as to impair the use of the water for a stated purpose • Standard method – analytical procedures to measure the impact of impurities on water

WASTEWATER CONSTITUENTS • Predicted on the intended use of the water • Water pollution – defined as the presence in water of impurities in such quantity and of such nature as to impair the use of the water for a stated purpose • Standard method – analytical procedures to measure the impact of impurities on water

WASTEWATER CONSTITUENTS

1. SUSPENDED SOLIDS SOURCES Natural contaminants resulting from the erosive action of water flowing over surfaces Result from human use of water – domestic wastewater Contain inorganic (clay, silt) or organic (plant fibers, bacteria)particles, immiscible liquids (oil and grease)

IMPACT Aesthetically displeasing Provide adsorption site for chemical and biological agents May be degraded biologically or may include diseases-causing organisms MEASUREMENT Filtering the water, drying the residue and filter to a constant weight at 104oC and lastly determine the mass of the residue retained on the filter

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FILTERABLE RESIDUE AND NONFILTERABLE RESIDUE Term used in laboratory analysis to represent the SS and DS Filterable residue closely related to DS while nonfilterable residue more closely to SS USE Measure the quality of wastewater influent Monitor several treatment processes Measure the quality of the effluent

2. TURBIDITY • A measure of the extent to which light is either absorbed or scattered by suspended material in water • Not a direct quantitative measurement of SS SOURCES  results from the erosion of colloidal material such as clay, silt, rock fragments, metal oxides from the soil, vegetables fiber, microorganism, soaps, detergent, emulsifying agents

IMPACT Aesthetically displeasing opaqueness will appear Provides adsorption sites for chemicals and biological organism that may be harmful or cause undesirable tastes and odors May interfere with light penetration and photosynthetic reactions in streams and lakes

MEASUREMENT Measured photometrically by determining the percentage of light of a given intensity that is either absorbed or scattered Turbidity is a relative measure, not absolute measures. It is usually expressed as nephelometric turbidity units (NTU) or as metres depth. Other units, formazin turbidity units (FTU) or Jackson turbidity units (JTU)

Turbidimeter using the scattered/transmitted light method

USE Made on ‘clean’ waters

3. COLOR • Apparent color – color of water partly due to suspended matter • True color – color contributed by DS SOURCES Yellowish-brown – water with organic debris Reddish – cause by iron oxide Brown/blackish – manganese oxide Industrial waste – textile and dyeing operations, food processing

IMPACT Unsuitable for laundering, dyeing, papermaking, dairy production Affect the market of domestic and industrial company Organic compound – reduce the effectiveness of chlorine as disinfectant MEASUREMENT Comparison with standardized colored materials (unit used TCU)

4. TASTE & ODOR SOURCES Mineral, metals and salts from the soil end products from biological reactions Inorganic substances – taste Alkaline material & metallic salts cause a bitter taste to water Organic material – contributed to both taste and odor

IMPACT Consumer associates T&O with contamination Organic substances – carcinogenic MEASUREMENT Can be made if the causative agents are known Organic cause – gas or liquid chromatography Qualitative test – threshold odor number (TON)

TON = (A + B)/A Where A = volume of odorous water (mL) B = volume of odor-free water required to produce a 200-mL mixture USE Serves as guideline for potable water TON of 3 recommended by the Public Health Service

5. TEMPERATURE Algae growth higher in warm water, causes algae mats – secrete oil and dead algae will causes taste & odor prob.

Affect solubilities of gases in water

Affect chemical reaction rate

IMPACT OF TEMPERATURE

Physical properties e.g viscosity and density – affect planktonic microorg.

Biological activities higher in higher T

CHEMICAL WATER QUALITY PARAMETERS

1. TDS

• Materials remaining in water after SS removal • Organic sources – decayed product of vegetation, organic chemical • Inorganic sources – minerals, metals, gases • Produce undesirable substances in water (color, taste, odor, toxicity problem) • Some are essential: distilled water taste flat, readily dissolved added to pure water to reduce its tendency to dissolve pipes and plumbing

2. ALKALINITY

• The ability of water to neutralize acids (quantity of ions that can neutralize H +) • Ions sources – dissolution of mineral substances in soil and atm (CO32-, HCO3-, OH-, NH3 etc) - HPO42- from detergent, fertilizers and insecticide - HS- and NH3- from byproduct of decomposition of organic material

3. HARDNESS • Amount of multivalent metallic cation in water – Sum of Ca & Mg ions in water – Other ions very little – Fe, Mn IMPACT

• Soap consumption higher • Form precipitation with soap – sticks to surface of sinks, dishwasher, rough skin, stain clothes • Economic loss: fouling of water heaters and boilers

4. FLUORIDE • Appears in groundwater in few geographical regions • Toxic in high conc, beneficial in low conc – 1 mg/L help prevent dental cavities, stronger teeth – >2 mg/L discoloration of teeth (mottling) – Higher conc – bone fluorosis

5. METALS NONTOXIC METAL • If exist in small amount – Zn, Fe, Mn, Al • Ca and Mg – hardness ions • Na – most common TOXIC • Mining and industrial industry • Ar, Ba, Cd, Pb, Hg – goes up food chain, greatest danger to top of chain MEASUREMENT – by AAS

6. NUTRIENTS • Nitrogen is often the limiting nutrient in ocean waters and some streams • Can exist in numerous forms, but most common are nitrate, nitrite, ammonia • Sources are primarily from fertilizers and acid deposition

• Phosphorus is typically the limiting nutrient in lakes and algae growth is linked to phosphorus inputs • Problems – Taste and odor in drinking water – Can be toxic, especially to farm animals – Fouling – Diurnal DO cycles

• Sources – fertilizers and detergents • Can exist in a variety of chemical forms, so total P is normally measured

7. ORGANICS • Soluble in water • Obtained from natural sources and human activities • Categories of dissolved organic – Biodegradable – Nonbiodegradable

7.1 BIODEGRADABLE ORGANICS • Consist of organics that can be utilized for food by naturally occurring microorg within a reasonable length of time • Organic material exist in dissolved from - starches, fats, proteins, alcohols, acids, aldehydes and esters • Microbial utilization involved oxidation (more efficient) and reduction

• BOD – the amount of O2 consumed during microbial utilization of organics (how much available O2 is used by bacteria to decay organic matter in the water) • BOD test: determine the O2 consumed from a sample placed in an airtight contained in controlled environment fro selected time. • Standard – 300 ml bottle, incubated at 20oC, 5 days in dark room (prevent algae growth – produce O2)

BOD CALCULATION

• Where DOi = initial DO (mg/L) DOf = final DO (mg/L) P = decimal fraction of sample in 300 mL bottle

BOD FROM SEWAGE TREATMENT PLANT IN MALAYSIA (2006) State

No. of STP

Total PE

Flow (m3/day)

BOD Load (kg/day)

Selangor

2,563

5,908,450

1,329,401

332,350.31

Perak

1,343

1,300,430

292,597

73,149.19

Johor

1010

1,198,417

269,644

67,410.96

Negeri Sembilan

928

931,458

209,578

52,394.51

Kedah

755

556,637

125,243

31,310.83

Melaka

725

570,192

128,293

32,073.30

Pulau Pinang

650

2,149,001

483,525

120,881.31

Pahang

486

314,830

70,837

17,709.19

WP Kuala Lumpur

299

2,571,877

578,672

144,668.08

Terengganu

224

75,184

16,916

4,229.10

Perlis

36

16,156

3,635

908.78

WP Labuan

32

39,265

8,835

2,208.66

9

72,833

16,387

4,096.86

9,060

15,704,730

3,533,563

883,391.08

WP Putrajaya Total

Example 1: Determining BOD5 The BOD of w/water is suspected to range from 50 to 200 mg/L. Three dilutions are prepared to cover this range. The procedure is the same in each case. First the sample is placed in the standard BOD bottle and is then diluted to 300 mL with organic-free, oxygen-saturated water. The initial DO is determined and the bottles tightly stoppered and placed in the incubator at 20oC for 5 days, after which the DO is again determined. Given:

Wastewater, L DOi (mg/L)

DOf (mg/L)

0.005

9.2

6.9

0.010

9.1

4.4

0.020

8.9

1.5

7.2 NONBIODEGRADABLE ORGANIC • Some organics materials are resistant to biological degradation – tannic and lignic acid, cellulose,phenols • Polysaccharides (strong bond) and benzene (ringed struct) are also nonbiodegradable e.g detergent compound ABS • Insecticide, herbicide, pesticide accumulate to top food chain, can cause extinction of animal species

BIOLOGICAL WATER QUALITY PARAMETER • All of biological community are water quality parameters 1. PATHOGEN • Organism capable of infecting, or transmitting disease to human • Usually require an animal host for growth and reproduction • Can be transported by natural water systems • Include bacteria, viruses, protozoa and helminths (parasitic worm)

1.1 BACTERIA

•Diseases causes by bacteria – gastrointestinal disorder, cholera, typhoid

1.2 VIRUSES

• Diseases – disorder of the nervous system, poliomyelitis, infectious hepatitis

1.3 PROTOZOA

• Diseases – dysentery, malaria

1.4 HELMINTHS

• Serious case of liver, intestine and urinary system

WATER QUALITY REQUIREMENTS • Vary according to the proposed use of the water • Represent a known/assumed need & based on prior experience of the water • WQS – set by government

WATER QUALITY STANDARDS • Standards

RIVER WATER QUALITY MONITORING • • • • • • •

BOD COD Ammonical nitrogen pH DO SS Optional – heavy metals and bacteria

WATER QUALITY INDEX • Give info on water quality conditions & trends • To measure the degree of water pollution and a tool in water quality classification • Reflect changes in physio-chemical quality of surface water & indicator of ecological change • Easiest method to explain the pollution level of water esp to public – using ranges between excellent, good, medium, bad and very bad

WQI - continuous • Is used to relate a group of variables to a common scale • Varies with changes in parameters values that would be indicative of changes in the quality of waters • WQI system and parameters vary from country to country • Measures general water quality conditions and does not reflect the presence of toxic compounds or specific toxic conditions