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