INDUSTRIAL POLLUTION Prof. Dr. Ir. Nastiti Siswi Indrasti.
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Transcript of INDUSTRIAL POLLUTION Prof. Dr. Ir. Nastiti Siswi Indrasti.
INDUSTRIAL POLLUTION
Prof. Dr. Ir. Nastiti Siswi Indrasti
Water Pollution
Prof. Dr. Ir. Nastiti Siswi Indrasti
Introduction Water pollution is an imprecise tern that reveals nothing
about either the type of polluting material or its source
Municipal wastewater, also called sewage, is a complex
mixture containing water (usually over 99%) together with
organic and inorganic contaminants, both suspended and
dissolved
Principles of Wastewater Treatment
Treatment processes
Physical treatment gravity settling is the most common physical processes for removing suspended solids from wastewater
Biological treatment most of the organic constituents in wastewater can serve as food (substrate) to provide energy for microbial growth
Chemical processes for municipal wastewater, precipitation and disinfection are the only processes having wide application
PRIMARY TREATMENT FACILITY
Screening Bar screens
Mechanical cutting/shredding Comminutor
Grid removal Grit chambers
Primary settling Sedimentation
BAR SCREENS
Bar screens retain floating debris such as wood, rags or other bulky objects that could clog pipes or damage mechanical equipment in the rest of plant
Figure 1. Typical bar screen installations
COMMINUTOR
Usually installed after coarse screens
Shreds and chops solid or rags that pass through the bar screen
Figure 2. Typical comminutor installation
Remove grit by collected them and reduction in velocity.
Figure 3. A mechanically cleaned grit chamber
SECONDARY (BIOLOGICAL) TREATMENT FACILITY
Trickling filters Activated sludge treatment Modification of the activated sludge process Other secondary treatment processes
Trickling filters
Figure 4. Cutaway view of a trickling filter
The trickling filter is a type of fixed-growth system: the microbes remain fixed or attached to a surface while the wastewater flows over that surface to provide contact with the organics.
Activated Sludge Treatment
Primarysettling
Pump
Secondary settling
Airblower
Activated sludgeAeration tank
Excess sludge
Secondaryeffluent
Mixed liquor
Compressed air
Return sludge
Primary effluent
Sewage influent
Figure 5. Typical activated sludge sewage treatment plant
Modifications Of The Activated Sludge Process
Figure 6. A typical extended aeration package plant installation
Modifications Of The Activated Sludge Process
Pump
Secondary clarifier
Activated sludgeAeration tank
waste sludge
Secondaryeffluent
air
Return sludge
Primary effluent
Figure 7. Flow diagram for the step aeration modification o the activated sludge
Other secondary treatment processes
Figure 8. Circular prefabricated steel sewage treatment plants
Other Secondary Treatment Processes
Figure 9. A series of rotating biological contractors, or biodiscs, for secondary wastewater treatment
TERTIARY (ADVANCED) TREATMENT FACILITY
Effluent polishing Phosphorus removal Nitrogen removal Land treatment of wastewater
Effluent polishing
Remove BOD and TSS from secondary effluents Using a mixed-media filter. The schematic diagram
of an automatic-backwash tertiary filter is shown in figure
Figure 10. Auto backwash rapid filters may be used to polish the effluent in a tertiary or advanced sewage treatment plant. Diagram (a) shows the filtration mode, and diagram (b) shows the backwash mode of operation (c) three individual filter cells may be constructed in a single prefabricated
Phosphorus Removal
Involves chemical precipitation of the phosphate ions and coagulation. The organic phosphorus compounds are entrapped in the coagulant flocks that are formed and settle out in a clarifier.
One chemical frequently used in this process is aluminum sulfate (alum), Al2SO4, the same coagulant chemical used to
purify drinking water.
Other coagulant chemicals that may be used to precipitate the phosphorus include ferric chloride (FeCl3) and lime, CaO
Phosphorus removal
Figure 9. Perspective view showing the basic components of micro-strainer unit
Nitrogen Removal
Figure 10. Schematic Diagram of Nitrogen Removal
Land treatment of wastewater Slow-rate infiltration systems spray irrigation, the most
popular land application process, involves the intermittent application of secondary effluent (usually) on crops, vegetation, or forest land
Rapid infiltration systems these systems require highly permeable soils to which wastewater is applied at high loading rates, to shallow, unvegetated basins
Overland flow in this systems, pretreated wastewater is applied to fairly impervious land having a slope o 2 to 8% so that substantial runoff (as laminar flow) is produced and then collected
On-Site Treatment Facilities Waterless Systems where no pressurized water is available
or soil conditions are unsuitable or effluent disposal, the choice for on-site treatment are limited to privies or waterless toilets
Septic Tank the most common method of on-site wastewater treatment and disposal, can be designed for a small family or a large institution
Package Plants where treatment by septic tank would be inadequate, anaerobic package plants can produce an effluent with a BOD and SS concentration 30 to 50% of that from a septic tank
SLUDGE FACILITY
Sludge treatment Sludge disposal
Sludge treatment
Land applicationCompost
Thickening Digestion
Sludge disposal options
Landfill
Dewatering
Incineration
Co-composting
Ash Sewage sludge
Dewatering
Figure 11. Alternative Pathways or Sewage Sludge Treatment and Disposal.
Figure 11. Schematic diagram of the two-stage anaerobic sludge digestion process
Digestion reduces the total mass or weight of sludge solids, destroys pathogens and makes it easier to dry or dewater the sludge
Figure 11. A section of a sludge drying bed
DEWATERING
Sludge dewatering is a process of removing enough water from a liquid sludge in order to change its consistency to that of moist earth
SLUDGE DISPOSAL
Ocean dumping Land filling Incineration Land application Sale as fertilizer
INTRODUCTION
Definition
The present of certain substances in the air in high enough concentrations and for long enough durations
to cause undesirable effects
Global & Regional Pollution
pollutants : acid deposition ; C02 ; CFC ; atomic reaction pollutants in nature or industry; heavy metal ; organochlorine from pesticide ;mountain activities; forest fire.
The example of regional pollutants : acid deposition
The component of acid deposition : SO2 and NO from the oxidation and hydrolysis H2SO4 ,HNO3 and CO2
CO2 is the main component of greenhouse effect and global warming beside the CFC and methane.
The effect in atmosphere causing the diminished ozone
The main pollutants in atmosphere
In the beginning, the air pollutants is detected by sensory perception without equipment
SO2 causing silver layer into black, damaged plants and in extreme situation causing hard breathing
Ozone causing rubber and synthetic material disturbed , in high concentration stimulate tear
The Influence Of Air Pollution
The Influences For Human Health
Base on US EPA 450-R-92-001 (1992), in the open air, Base on US EPA 450-R-92-001 (1992), in the open air, there are :there are :
solid particle and liquid particlesolid particle and liquid particle
Sulfur oxideSulfur oxide
carbon monoxidecarbon monoxide
Nitrogen dioxideNitrogen dioxide
PbPb
The Influences for Plants and HumanThe Influences for Plants and Human
In A biotic environmentIn A biotic environment
SulfurSulfur Nitrogen Nitrogen FluorineFluorine Hydrogen sulfide with Pb oxide Hydrogen sulfide with Pb oxide
Gas Emission Control
1. Decrease or omitted the unnecessary production
2. Produce the good gas emission for the environment
3. Transfer the unnecessary gas emission by absorption, there are transferring the gas into water or deposition of gas molecule into solid surface
There are 3 general ways to reduce the gas emission :
SOLID WASTE
Prof. Dr. Ir. NASTITI SISWI INDRASTI
SOLID WASTE MANAGEMENT
INFRASTRUCTUREACTIVITIES
Design
Planning
Financing
Construction
Operation Disposal
Recycling
Processing
Transport
Collection
Solid waste characteristic Type of solid waste
Municipal solid waste (MSW): non-hazardous solid waste from a city, town, village that requires routine or a periodic collection and transport to a processing or disposal site
NON Municipal Solid Waste: include industrial process waste, construction and demolition debris, sewage sludge, mining waste or agricultural waste.
Municipal solid waste
Rubbish
a periodic collection Routine collection
Waste processing Energy recovery
Recycling
Final disposal
Garbage
Refuse Trash
Figure 1. General classification of municipal solid wastes (MSW)
Solid waste collection
Collection includes temporary storage or containerization, transfer to a collection vehicle and transport to a site where the waste undergoes processing and ultimate disposal.
Waste collection is the most expensive phase, largely because it is labor intensive.
In fully automatic systems, an articulated arm mechanism on the vehicle engages, lifts, empties and replaces the container without manual assistance.
Semiautomatic systems require a truck crew member to place the container in position to be automatically hoisted and emptied into the collection truck and then manually returned to its setout position
Mechanical collection systems
Semiautomatic systemsAutomatic systems
Transfer station is a facility at which solid wastes from individual collection trucks are consolidates into larger vehicles, such as tractor-trailer units. There are two basic modes of operation: direct discharge or storage discharge.
In storage discharge transfer station, the refuse is first emptied from the collection trucks into a storage pit or onto a large platform.
In a direct discharge station, each refuse truck empties directly into the larger transport vehicles.
Solid waste collection
Solid waste processing Reduce the total volume and weight Changes its form and improve its handling
characteristic To recover natural resources and energy in the waste
material for reuse or recycling The most widely used municipal waste treatment
processes including incineration, shredding, pulverizing, baling and composting.
Incineration Incineration is a thermal oxidation with the furnace
temperatures are about 815-1400 0C. Incineration result:
POC (product of complete combustion): CO2, H2O PIC( product of incomplete combustion): CO2,
hydrocarbon, amine, organic acid, polycyclic organic matter, etc.
The incineration result composition is influenced with the waste characteristic
Incineration requirements: excessive oxygen to minimize the PIC
Operation of incinerator
• Good understanding of waste characteristics
• Technical skills• Control of waste feed • Mixing of wastes • Temperature to be kept at required
level despite variations in waste• Excess air• Flue gas control• Regular maintenance
Must be consistentNeeds:
Source: David C Wilson
Energy recoveryWaste combustion produces heat but combustion of low CV wastes may not be self-supporting
Energy recovery is via production of steam to generate electricity
• Only steam production: 80% efficiency is typical• Steam can be used for in-house demands• Steam can be delivered to adjacent users eg other industrial
plants• Electricity can be generated: 25% efficiency typical
Opportunities to sell heat are improved where facilities are in industrial areas
Sale of surplus energy improves plant economics
Source: Indaver
Figure 4. Schematic of rotary kiln waste-to-energy furnace
Pyrolysis
Pyrolysis = thermal decomposition process which takes place in the total absence of oxygen
Products of pyrolysis: •combustible gases•mixed liquid residue
Advantages: •low operating temperature •no need for excess air so less flue gas•by-products are combustible
Gasification
Gasification = incomplete combustion in the partial absence of oxygen
Enables efficient destruction of hazardous waste at lower temperatures than incineration
Thermal destruction is ensured by a combination of high-temperature oxidation followed by high temperature reduction
Size reduction of municipal solid waste such as cutting and tearing, where as pulverizing refers to the actions of crushing and grinding
Shredding and Pulverizing
Hammer mills: types of equipment used for processing MSW into uniform or homogeneous mass
Figure 5. Vertical Hammer Mill
Baling: compacting solid waste into the form of rectangular blocks or bales.
High-pressure compaction units
Composting Composting is a process in which the organic portion of
MSW is allowed to decompose under carefully controlled conditions by the action of bacteria, fungi and other microorganism
With proper control of moisture, temperature and aeration, a composting plant can reduce the volume of the raw organic material by as much as 50 percent.
A complete municipal solid waste composting operation includes sorting and separating, shredding and pulverizing, digestion product upgrading and marketing.
The composting waste is aerated by periodically turning each windrow. This can be done manually with a pitchfork, but at most large facilities it is machinery. Some of these machines turn and rebuild the windrow directly behind the machine; others rebuild the turned windrow adjacent to its original position figure 6
Figure 6. (a) windrow turning machine (b) windrow turning arrangement
Co-composting An interesting example of integrated
waste management is a co-composting of municipal solid waste and sewage sludge.
Sewage sludge adds nitrogen, phosphorus and other elements that enrich the solid waste and helps the composting process
Figure 7. Enclosed mechanical-type composting system(reprinted with permission from composting and recycling, Louis F. Diaz, 1993)
Figure 8. Schematic of aerated static pile composting system.(Tchobanglous, G., et. al.)
Recycling
What is recycling? • The re-use and remanufacture of
waste materials
What is the purpose of recycling?• To recover useful materials and save
resources• To prevent pollutants reaching the
waste stream
What are the benefits of recycling?• More efficient resource use, lower
energy consumption, reduced pollution