GENERAL ENGINEERING

Wastewater

water whose physical, chemical or biological properties have been changed as a result of the introduction of certain substances which render it unsafe for some purposes such as drinking.

wastewater treatment

the process and technology that is used to remove most of the contaminants that are found in wastewater to ensure a sound environment and good public health

waste water management

handling wastewater to protect the environment to ensure public health, economic, social and political soundness

carbon, nitrogen, phosphorus, sulphur

needs to be broken down by oxidation into gases which is either released or remains in solution to reduce biodegradable organic substances in environment.

nitrogen and phosphorous

enrich water bodies or render it eutrophic leading to the growth of algae and other aquatic plants wherein the plants deplete oxygen in water bodies and this hampers aquatic life.

Pathogens

organisms that cause disease in plants, animals and humans

Stormwater runoff

water from streets, open yard etc after a rainfall event which run through drains or sewers

industrial wastewater

liquid from industrial establishments

domestic wastewater

"municipal wastewater" from residences grey to blackwater

greywater

from washrooms, laundries, kitchens

blackwater

generated in toilets

sewage

blackwater if ends in sewerage system

septage

blackwater if ends up in septic tank

sewerage system

arrange of pipes laid for conveying sewage

influent

wastewater which is yet to enter in a wastewater treatment plant

effluent

liquid discharge from wastewater treatment plan

sludge

semi-solid slurry from wastewater treatment plant

On-site system

wastewater disposal method which takes place at the point of waste production

off-site system

wastewater transported to a place either than the point of production.

off-site methods

examples are bucket latrines, pour-flush toilets with vault and tanker removal and conventional sewerage system.

conventional sewerage system

can be combined sewers or separated sewers

septic tank

an on site system designed to hold blackwater for sufficiently long period allowing sedimentation

faecal sludge

all sludge collected and transported by vacuum trucks

unit operation

involves removal of contaminants by physical forces

unit process

involves biological and chemical removal of contaminants

wastewater treatment plant

plant with series of designed unit operations and processes

electrical conductivity (EC)

indicates salt content

Total dissolved solids (TDS)

comprise inorganic salts and small amounts of organic matter dissolved in water

suspended solids (SS)

comprisessolid particles suspended but not dissolved in water

dissolved oxygen (DO)

indicates the amount of oxygen in water

biochemical oxygen demand (BOD)

indicates amount of oxygen required by aerobic microorganisms to decompose

chemical oxygen demand (COD)

indicates oxygen equivalent of organic matter content of a sample that is susceptible to oxidation

total kjeldhal nitrogen

measurement of organically-bound ammonia nitrogen

total-P

reflects the amount of all forms of phosphorus in a sample

Total coliforms (TC)

encompassing faecal coliforms as well as common soil microorganisms, and is broad indicator of possible water contamination

Faecal coliforms (FC)

indicator of water contamination with faecal matter

Escherichia coli / E.coli

common lead indicator

helminth

analysis looks for worm eggs in water

Coagulation

used to remove turbidity, color and bacteria from drinking waters.

goal is to change the surface charge on the particles so they can stick together to form larger particles that will settle by gravity.

Coagulant

a chemical that is added to the water to cause the particles to coagulate

aluminum and ferric ion

Most commonly used coagulants

pH & dose

Two important factors in coagulant addition

Mixing or Rapid Mixing

the process whereby the chemicals are quickly and uniformly dispersed in the water.

Flocculation

contacting process in which precipitates must be brought into contact with one another so they can form flocs.

Hardness

used to characterize a water that does not lather well, causes a scum in the bath tub and leaves hard, white, crusty deposits

Ion Exchange Softening

defined as the reversible exchange of an ion on a solid phase with an ion of like charge in an aqueous phase.

Sedimentation

required process prior to subsequent treatment when surface water contains high turbidity.

Sedimentation basins

also called clarifiers or settling tanks.

usually rectangular or circular with either a radial or upward water flow pattern.

Filtration

process by which water flows slowly through a bed of granular media, usually sand, anthracite coal or garnet.

Disinfection

used in water treatment to kill pathogens present I water that would cause mild to fatal illness if ingested.

not the same as sterilization as this implies to destruction of all living organisms.

Sludge

semi-solid slurry and can be produced as sewage sludge from wastewater treatment processes or as a settled suspension

Generic term for solids separated from suspension in a liquid.

Thickening

separating as much water as possible by gravity or flotation.

Stabilization

converting the organic solids to more refractory (inert) forms so that they can be handle or used as soil conditioners without causing a nuisance or health hazard through processes referred to as digestion.

Conditioning

treating the sludge with chemicals or heat so that the water can be readily separated.

Dewatering

separating water by subjecting the sludge to vacuum, pressure or drying.

Reduction

convening the solids to a stable form by wet oxidation or incineration. These are chemical oxidation processes which decrease the volume of sludge

Limited Plants

have a high quality water source and employ very specific like disinfection, corrosion control, fluoridation, iron/manganese removal and softening.

-used only for the treatment of groundwater as a raw water source.

Coagulation Plants

-used to treat surface water.

-rapid mixing, flocculation, sedimentation, filtration and disinfection are employed to remove color, turbidity, taste and odors and bacteria.

Softening Plants

-used to treat waters having a high hardness level

INDUSTRIAL WASTEWATER TREATMENT

deals with the processes used for treating wastewater (liquid wastes) produced by industries as undesirable by-products.

absolute hazardous

hazardous not because of the composition of the wastes but by virtue of process that produced them, the same is true for the non-hazardous absolute

mirror entries

can either be nonhazardous or hazardous depending on the waste composition

Food industry

SOURCES OF INDUSTRIAL WASTEWATER

it is non-toxic Biodegradable -has high concentrations of Biological Oxygen Demand (BOD) and suspended solids (SS)

Iron and steel industries

SOURCES OF INDUSTRIAL WASTEWATER The contamination of waste streams includes the gasification products such as naphthalene, benzene, anthracene, ammonia, phenols, cyanide, cresols along with a variety of more complex organic compounds collectively called polycyclic aromatic hydrocarbons

Mines and quarries

SOURCES OF INDUSTRIAL WASTEWATER

slurries of the rock particles in water

Battery manufacturing

SOURCES OF INDUSTRIAL WASTEWATER

The pollutants generated at battery manufacturing plants includes lead, manganese, mercury, nickel, chromium, cobalt, copper, cadmium, cyanide, iron, oil and grease, silver and zinc

Electric power plants

SOURCES OF INDUSTRIAL WASTEWATER

discharge wastewater with significant amounts of metals such as lead, cadmium, chromium, and mercury, as well as arsenic, nitrogen compounds (nitrites and nitrates), and selenium.

Wastewater streams include fly ash, flue-gas desulfurization, bottom ash, and flue gas mercury controls

Textile industries

SOURCES OF INDUSTRIAL WASTEWATER

Pollutants generated by textile mills include oil and grease, BOD, sulfide, phenols and chromium

Insecticide residues in fleeces are particular problem in treating wastewater generated in wool processing.

Petroleum refining and petrochemicals industries

SOURCES OF INDUSTRIAL WASTEWATER Pollutants discharged include the conventional pollutants (BOD, oil and grease, COD, SS), ammonia, phenols, sulfides, and chromium.

Paper and pulp industries

SOURCES OF INDUSTRIAL WASTEWATER Effluents are generally high in BOD and suspended solids.

INDUSTRIAL WASTE

can be solid, liquid, or gas and each type has different methods of disposal and management.

Waste in general is produced by human activity, for instance, extraction and processing of raw materials.

INDUSTRIAL WASTE MANAGEMENT

deals with all types of wastes relating to industries, including industrial, biological and household, before, during, or after production, and even after usage by consumers.

intentionally done to reduce the adverse effects of waste on the environment and human health.

WASTE CHARACTERIZATION

process by which the composition of different streams of waste are analyzed

plays important role in any waste treatment; industrial or non- industrial.

RISK ASSESSMENT

the systematic process of evaluating the potential risks which may be involved in a projected waste management activity or undertaking.

1. Hazard Identification

2. Exposure Assessment

3. Risk Characterization

HAZARD

something that could potentially cause harm

RISK

the degree of likelihood that harm will be caused

Hazard Identification

identifying and characterizing source of the potential risk

Exposure Assessment

determining exposure routes and pathways from the source to individual

EXPOSURE

the bridge between what is regarded as a hazard and what in reality presents a risk

Risk Characterization

determining who can be likely affected and what likely effects could be.

Air Pollution

occurs when gases, dust particles, fumes (or smoke) or odour are introduced into the atmosphere in a way that makes it harmful to humans, animals and plant.

It creates smog and acid rain, causes cancer and respiratory diseases, reduces the ozone layer atmosphere and contributes to global warming.

Air Pollutant

Substance in the air that can be adverse to human and the environment

can be in form of solid particles, liquid droplets or gases

it can be natural or man made

Primary pollutants

directly produced from a process

Secondary pollutants

not emitted directly

they form in air when primary pollutants react or interact

sulphur oxides

PRIMARY produced by volcanoes and in various industrial processes

Combustion of coal and petroleum

Nitrogen oxides

PRIMARY expelled from high temperature combustion

also produced naturally during thunderstorms by electric discharge

Can be seen as the brown haze dome above or plume downwind of cities

Carbon monoxide

PRIMARY is a colourless, odourless, non-irritating but very poisonous gas.

It is a product by incomplete combustion of fuel such as natural gas, coal or wood. Vehicular exhaust is a major source of carbon monoxide

Volatile organic compounds

PRIMARY divided into the separate categories of methane (CH4) and nonmethane (NMVOCs).

Particulates

PRIMARY alternatively referred to as particulate matter (PM), atmospheric particulate matter, or fine particles, are tiny particles of solid or liquid suspended in a gas.

can be manmade or natural.

Persistent free radicals

PRIMARY connected to airborne fine particles could cause cardiopulmonary disease

chlorofluorocarbons

PRIMARY harmful to ozone layer emitted from products currently banned from use

Ammonia (NH3)

PRIMARY emitted from agricultural processes. Building block for synthesis of many pharmaceuticals

Radioactive Pollutants

PRIMARY Produced by nuclear explosions, nuclear events, war explosives and natural processes

Particulates

SECONDARY Created from gaseous primary pollutants and compounds in photochemical smog

Ground Level Ozone

SECONDARY formed from NOx and VOCs

At abnormally high concentrations brought about by human activities (largely the combustion of fossil fuel), it is a pollutant, and a constituent of smog.

Industrial air pollutants

Thermal Power Plants Boilers Thermic Fluid Heaters Incinerators blast furnace Coke oven Basic Oxygen Furnace Induction and air Furnace Cement kilns

AIR POLLUTION CONTROL

Control measure examples are: a. collecting pollutants using equipment b. destroying the pollutants by thermal or catalytic combustion c. changing the pollutants to less toxic form d. releasing pollutants through tall chimneys/stack for greater dispersion

SOLID WASTE

refers to the range of garbage materials arising from animal and human activities that are discarded as unwanted and useless.

generated from industrial, residential, and commercial activities in a given area, and may be handled in a variety of ways.

landfills

are typically classified as sanitary, municipal, construction and demolition, or industrial waste sites.

INDUSTRIAL WASTE SITE

non-hazardous industrial solid waste

commercial solid waste