1.eBook Ipal Why Treat

TatyAlfiah/Sabtu, 21 September 2013Hlm - 1

Mata Kulia Desain Instalasi Pengolah Air Limbah (IPAL)Kode MK / Sks / Smtr 1309701 / 4 sks / VIIProgram Studi Teknik Lingkungan

Fakultas Teknik Sipil dan PerencanaanInstitut Teknologi Adhi Tama Surabaya [ITATS}

Dosen Taty Alfiah, ST.MT.

Why treat wastewater ?


SOURCES OF WASTEWATER

Wastewater can originate from many sources such as; homes, businesses and industries.Storm water, surface water and ground water can enter the wastewater collection systemand add to the volume of wastewater.The source of a wastewater will determine its characteristics and how it must betreated.

Types of wastewater : Domestic Wastewater wastewater from homes and businesses (from homes,

offices, hotels, institutions) typically contains pollutants such as; sewage (humanwaste; fecal ; black water) and greywater from bathrooms, kitchens, laundries)vegetable matter, grease and scum, detergents, rags and sediment.












Industrial Wastewater is the liquid discharge from manufacturing processes; forexample soft drink and beer companies; sugar processing; metal processing;photo finishing . wastewater from an industrial process (industrial wastewater)may include; toxic chemicals and metals, very strong organic wastes, radioactivewastes, large amounts of sediment, high temperature waste or acidic/causticwaste.

Wastewater could even come from streets and parking lots during a rainstorm(storm wastewater) that could contain; motor oil, gasoline, pesticides, herbicidesand sediment.

yellow water: human urinebrown water: human faeces with flushed water (can include paper if used)black water: human faeces (brown water) mixed with urine (yellow water), in general:

wastewater from toilets. It contains human waste and can be a publichealth risk if not treated properly. (Sometimes, water used in kitchen isalso classified as black water)

grey water: water used in the kitchen, bathroom including sinks, baths, showers andlaundry, etc. or any water that has been used at home, except water fromtoilets


There are two routes by which pollutants enter receiving waters: point sources, such as a wastewater treatment plant discharges from an outfall

pipe. Wastewater treatment plants, and wastewater treatment plant operators,control point source pollution.

non-point sources, such as agricultural and industrial pollution that originatesfrom a widespread discharge. non-point source pollution is not limited to a singleoutfall pipe, it is very hard to control.

Waste discharges pollutant can be placed into two broad categories: Organic Wastes are those substances that contain the element carbon and are

derived from something that was once living. Examples include: vegetable andfecal matter, grease, proteins, sugars and paper.

Inorganic Wastes are those substances that do not contain carbon and are notderived from something that was once living. Examples include: metals, minerals,salts, acids and bases.


EFFECTS OF DISCHARGING WASTES

Organic Waste (in general)Organic waste, such as fecal and vegetable matter, toilet paper and sugars can causea series of problems in receiving waters. One problem is oxygen depletion. Manyaquatic organisms, including fish, need dissolved oxygen (O2) to survive. These typesof organisms are referred to as aerobes and the environment they live in as aerobic.Much like you and I, aerobic bacteria breath in O2 and produce carbondi-oxide (CO2) as a by-product. Natural surface waters typically contain enough dissolved oxygento support aerobic organisms. Oxygen depletion can occur when aerobic bacteriause excess organic waste discharged into a receiving stream as food. As the aerobicbacteria multiply, they require more and more dissolved oxygen to sustain theirgrowing numbers. When the population of aerobic bacteria grows large enough,they utilize more oxygen than is available in the river. After this happens, they (andmost other aerobic organisms) in the river, die.When all of the dissolved oxygen in a river has been consumed, another type oforganism begins to grow in the altered environment. Anaerobic bacteria live inconditions where there is no dissolved oxygen (septic). Anaerobic bacteria breatheby using the oxygen that is chemically combined with other elements, such as sulfate(SO4). When anaerobic bacteria use the oxygen from sulfate for respiration,hydrogen sulfide (H2S) gas is released as a byproduct. Hydrogen sulfide, sometimescalled sewer gas, smells like rotten eggs and is very dangerous due to its explosive,toxic and suffocating characteristics. Oxygen depleted conditions lead to the growthof anaerobic bacteria, which results in odors in receiving waters. Furthermore,anaerobic bacteria release other objectionable by-products, such as organic acids,methane gas and nutrients, all of which can further harm the natural environment inthe receiving stream. Because of the chain of events that the discharge of organicwaste sets into motion, one of the principal goals of wastewater treatment is toprevent as much of it from getting into receiving waters as possible.

NutrientsNutrients are substances that are required for the growth of living plants andanimals. Some major nutrients are nitrogen and phosphorous. Both are found inwastewater in various forms. Nitrogen is typically present in influent in the forms ofammonia (NH4) and organically bound nitrogen. Both nitrogen compounds can bemeasured by the Total Kjeldahl Nitrogen (TKN) test. Nitrogen may be present ineffluent as ammonia, organically bound nitrogen or even nitrite (NO2) and nitrate(NO3). Phosphorous is present in influent and effluent primarily in the form ofphosphates (PO43). When large amounts of nutrients are allowed to enter into riversand lakes, they can cause problems by increasing the growth of plants, such as algae.


If the algae growth is extensive, it can choke up the water body. As the lower layersof algae are blocked off from the sun, they die and end up as food for bacteria. Thisbegins the cycle described earlier under organic waste discharges, which leads tooxygen depletion.






Suspended SolidsInorganic suspended material like sand, dirt and silt and organic material like sludgeboth deposit on river bottoms and prevent fish from spawning. Point sourcedischarges of sludge and sediment can cause the same problem.

Sludge and ScumSludge and scum are a component of domestic wastewater and some industrialwastewaters. They are primarily organic in nature. If not removed by thewastewater treatment plant, sludge and scum will accumulate on river bottoms andstream banks. Sludge deposits on river bottoms can prevent fish (particularly trout)from being able to spawn. Scum accumulated on stream banks can cause odorproblems, can harbor infectious diseases and is unsightly.

Pathogenic OrganismsThe main microorganisms of concern in wastewater treatment are Bacteria, Fungi,Algae, Protozoa, Viruses, and pathogenic microorganisms groups.Wastewater can potentially contain any disease causing organism, or pathogen, thatthe people contributing waste to the collection system are infected with. Commondiseases caused by water borne pathogens include; typhoid, hepatitis, cholera,dysentery and polio.If pathogens are discharged without treatment into the natural environment, they willpose a danger to anyone that is exposed to them. For this reason, one of the primarygoals of wastewater treatment is to disinfect the effluent before it is discharged.The group of microorganisms that we use to indicate the level of pathogeniccontamination is the Fecal Coliform group. Fecal Coliform are a group of organismsthat live in the intestinal tract of all warm blooded animals, including man. If FecalColiform are detected in water, it indicates that a warm-blooded animal hasdefecated into the water and therefore pathogens could be present. Although somemembers of the Fecal Coliform group are harmful to humans, such as toxin producingstrains of Esterichia Coli (E. coli), they are not pathogens. As a whole, we all live quitecomfortably as host to the billions, if not trillions, of Fecal Coliform in our intestines.

Temperature EffectsHigh temperature discharges can disrupt the natural ecology in surface waters byencouraging the growth of algae and aquatic plants that would not normally be asabundant. In addition, seasonal temperature changes can cause the treatment plantto operate less efficiently. This is most evident during cold weather because thegrowth and activity of the microorganisms in the treatment plant slows downconsiderably.

pH


pH is a measurement of waters acid or alkaline condition. pH is measured on a scalethat spans from 0 to 14 with 7 being the middle, or neutral value. pH values lowerthan 7 are progressively acidic while pH values that are higher than 7 areprogressively basic, (also called caustic or alkaline). Most living organisms live in anarrow pH range that is near neutral. If an effluent has a pH that is higher or lowerthan that of the receiving water, the organisms in the receiving water may be killedoff. In addition, if the pH of the influent coming into a wastewater treatment plantchanges rapidly and significantly, the plant treatment processes may be disrupted.

WHY TREAT WASTEWATER??When untreated wastewater accumulates and is allowed to go septic, the decompositionof the organic matter it contains will lead to nuisance conditions including the productionof malodorous gases. In addition, untreated wastewater contains numerous pathogenicmicroorganisms that dwell in the human intestinal tract. Wastewater also containsnutrients, which can stimulate the growth of aquatic plants, and may contain toxiccompounds or compounds that potentially may be mutagenic or carcinogenic. For thesereasons, the immediate and nuisance-free removal of wastewater from its sources ofgeneration, followed by treatment, reuse, or dispersal into the environment is necessaryto protect public health and the environment.

The goals of wastewater treatment are : Protection of public health

o Wastewater contains pathogenic microorganisms lead to dangerous












o diseases to humans and animalso Hazardous matter such as heavy metals that are toxico Produces odorous gases and bad smell

Protection the environment (to prevent groundwater pollution, to prevent soilpollution, to prevent sea shore , to prevent marine life)

o Raw Wastewater leads to septic conditions in the environment andconsequently leads to the deterioration of surface and groundwaterquality and pollutes the soil.

o Raw wastewater is rich with nitrogen and phosphorus (N, P) andleads to the phenomena of EUTROPHICATION. EUTROPHICATION isthe growth of huge amounts of algae and other aquatic plantsleading to the deterioration of the water quality.

o Raw wastewater is rich with organic matter which consumes oxygenin aquatic environment.

o Raw wastewater may contains toxic gases and volatile organic matter To reuse the treated effluent (For agriculture ; For groundwater recharge ; For

industrial recycle) Solving social problems caused by the accumulation of wastewater

The ultimate goal of wastewater engineering is the protection of public health in amanner commensurate with environmental, economic, social, and political concerns. Toprotect public health and the environment, it is necessary to have knowledge of(1) constituents of concern in wastewater,(2) impacts of these constituents when wastewater is dispersed into the environment,(3) the transformation and long-term fate of these constituents in treatment processes,(4) treatment methods that can be used to remove or modify the constituents found in

wastewater, and(5) methods for beneficial use or disposal of solids generated by the treatment systems.


Schematic diagram of a wastewater management infrastructure.

WASTEWATER MANAGEMENTGenerationCollectionTreatmentDisposal

Collection of WasTeWaTerIn a modern society wastewater is carried from houses in underground pipes or sewers.Normally the wastewater (sewage) flows by gravity but sometimes pumping stations areneeded in flat areas. As sewers meet and flow increases the sewer gets bigger and inlarge cities can be several metresIn older parts of towns and cities sewers may also collect rainwater from roofs androadways. In wet weather some cannot cope with the high flows and are designed tooverflow to watercourses.These are called combined sewer overflows and in recent years the impact of these onthe water environment has been considerably reduced.


.


Levels of wastewater treatment

Preliminary Removal of wastewater constituents such as rags, sticks, floatables, grit, andgrease that may cause maintenance or operational problems with the treatmentoperations, processes, and ancillary systems

Primary Removal of a portion of the suspended solids and organic matter from thewastewater

Advanced primary Enhanced removal of suspended solids and organic matter from thewastewater. Typically accomplished by chemical addition or filtration

Secondary Removal of biodegradable organic matter (in solution or suspension) andsuspended solids. Disinfection is also typically included in the definition ofconventional secondary treatment

Secondary with nutrients Removal of biodegradable organics, suspended solids, andnutrient removal (nitrogen, phosphorus, or both nitrogen and phosphorus)


Tertiary Removal of residual suspended solids (after secondary treatment), usually bygranular medium filtration or microscreens. Disinfection is also typically a part oftertiary treatment. Nutrient removal is often included in this definition

Advanced Removal of dissolved and suspended materials remaining after normalbiological treatment when required for various water reuse applications

How you can help

Treatment plants do an amazing job of cleaning wastewater, but they are the last line ofdefense in protecting water quality. You are the first line of defense. Here are threeeasy things you can do to protect water quality and minimize treatment cost.1. Keep non-biodegradable materials out of the system.

Put hair, feminine hygiene products, cotton swabs, and grease in the garbage. The system is only designed to handle biodegradable waste such as human waste,

toilet paper, and non-greasy food scraps. Non-biodegradable materials must be removed at the treatment plant and sent to

a landfill. Non-biodegradable materials cause problems by clogging pipes.

2. Keep hazardous waste out of the system. Never put hazardous waste down the drain! Hazardous waste is any material that can catch fire, explode, corrode, or is toxic. Hazardous waste includes pesticides, herbicides, solvents, paint thinners, and

engine oil.3. Reduce your water consumption.

Contact us for a brochure full of tips to reduce your water use. Conserving water saves money and protects the environment since the less water

you use, the less wastewater we have to treat.

1.eBook Ipal Why Treat

Documents

Transcript of 1.eBook Ipal Why Treat