hazardous waste-management
DESCRIPTION
TRANSCRIPT
Hazardous Waste Management:Overview
Waste Management
Definition of Hazardous Waste
A solid or liquid wastes which because of its quantity, concentration or physical, chemical or infectious characteristics, may:
1. Cause increase in mortality or severe illness,
2. Pose a substantial potential hazard to human health or environment, when improperly treated, stored, transported or disposed
Definition of Hazardous Waste
Characteristics of Hazardous Waste
Ignitability (flash point >60oC)
Corrosivity (pH <2 or >12.5)
Reactivity (unstable materials or material that cause violent reaction when in contact with another material)
Toxicity (Leachate Test)
Nature of Hazardous Waste Management
Hazardous Waste field is interdisciplinary
Requires professionals with diverse background working together to solve the complex issue of hazardous waste management
Environmental Impact and Risk Assessment
Treatment, Storage and Disposal
Waste Minimization, Recycling and Reduction
Management and Cost
Past Disposal Practice
Soil Spreading
Pits/Ponds/Lagoons
Sanitary Landfills
Drum Storage Areas
Underground Storage Tanks
Midnight Dumping
Uncontrolled Incineration
Waste Generation Rates By Industry
Chemical Products Electronics
Petroleum & Coal Products Primary Metals
Transportation Equipment All Other Industries
Typical Hazardous Waste Types
70%
25%
Inorganic Liquid Organic Liquid Sludge
Why the need for HWTC?
Protect public health and the environmentReduce impact of hazardous waste on surface water and ground waterProvide the means to enhance:
Waste minimization at various industrial operations, andWaste recycling
Objectives of HWTC 1. Avoid and minimize environmental
and health pollution risks associated with the generation, storage, collection, transport, handling, recycling, and disposal of hazardous wastes
2. Ensure the movement and disposal practice of hazardous wastes is always controlled and environmentally safe, flexible, and economically sustainable for local conditions
Technical Feasibility Can the wastes be
separated at source to avoid co-mingling and analyzed before shipping to the facility?
What characteristics are the separated wastes likely to have?
What quantity of the wastes should be considered as wastewater?
Market and Economic Feasibility Is there a local market for the products
of recycling? Is there an international market for the
products of recycling?What scale of disposal fees is to be
expected for each category of waste?What rate of return would a Private
Sector investor expect for providing and operating a Hazardous Waste Recycling Facility?
Materials Disposed in HWTC Liquid organic wasteOily sludge and residue from petroleum industry Spent oil and catalystsContaminated soil Liquid heavy metalsAcidic and basic solids and liquids Liquid ammonia and ureaOff-Specification products
Estimation of Hazardous Wastes Quantities??
Hazardous Waste Inventory:
Estimate the total waste stream quantityDeduct the portion of these wastes that are being recycled or processed at the generator’s own facilitiesDeduct any co-mingled wastes that are impossible to separate in a cost-effective manner
Estimation of Hazardous Wastes Quantities (cont.)
Deduct waste quantities being disposed without permitPrepare an integrated treatment system for the remainder with add-on facilities for growth and improvement in anticipation of reducing any unauthorized disposalPropose action as necessary for treatment and disposal facilities for the co-mingled and improperly disposed wastes
HWTC Design Approach
1. A flexible modular design will provide the Project Authority with the opportunity to attract private sector investments and will minimize capital cost in the long-term
– Focus initially on the major polluters– Provide HWTC to treat part of the waste– Initiate and monitor
HWTC Design Approach (cont.)
2. Due to the nature of the hazardous wastes and their potential to change characteristics and properties over time, the HWTC needs to be properly designed and equipped with facilities that are capable of safely meeting the needs of handling and disposing the hazardous waste
Description of the HWTC
Liquid Waste Treatment FacilityLand Farming FacilityClass I Hazardous Waste LandfillClass II Regular Waste Landfill Solidification and Stabilization UnitIncinerator
Important Points
The priorities of hazardous Waste management in decreasing order of importance:
Minimization/Prevention
Treatment/Remediation
Disposal
Liquid Waste Treatment Facility
Separate tank farm storage for acidic and basic waste as well as drum storage areaNeutralization reactorsSludge storage reactorStandby neutralization reactors to be used during maintenance
Activated Carbon Column
Liquid Phase Adsorption Treatment System
Industrial Wastewater Treatment
Chemical Oxidation
In general the objective of chemical oxidation is to detoxify waste by adding an oxidizing agent to chemically transform waste componentsChemical oxidation is a well established technology that is capable of destroying a wide range of organic molecules, including chlorinated VOCs, phenols and inorganics such as cyanide
Process Description Chemical Oxidation is based on the delivery of oxidants to contaminated media in order to either destroy the contaminants by converting them to innocuous compounds commonly found in nature
The oxidants applied are typically hydrogen peroxide (H2O2), potassium permanganate (KMnO2), ozone (O3)
Process Description
Land farming is the preferred technology for the treatment of oily sludge and hydrocarbon contaminated soils, which constitute the main component of hazardous organic wastes to be treated at the HWTC
Land Farming Facility
Base Liner Detail
SUBSOILGEOMEMBRANE
WASTE
FILTER SOILGRAVEL W/PERFORATED PIPE
Compounds to be treated at the land Farming Facility:
Volatile Organic Compounds (VOCs): benzene, ethylbenzene, toluene, xylenes;
Semi-Volatile Organic Compounds (SVOCs): phenols, creosol, naphthalene, phennathrene, benzo(a)pyrene, flourrene, anthracene, chrysene; and
Heavy Metals: chromium, cyanides, lead and nickel
Land Farming Facility (cont’d)
Aerobic Biodegradation
ORGANICPOLLUTANT + MICROORGANISMS + NUTRIENTS + OXYGEN
CARBON DIOXIDE + WATER + BIOMASS
HYDROCARBONPRODUCT
Microorganisms
• Regarding the natural breakdown of hydrocarbon products, bacteria are the main microorganism in the bioremediation process
• Bacteria act as decomposers and utilize hydrocarbon product as a source of energy
Nutrients
Nutrients enhance the biodegradation process by supplying essential elements required for optimal microbial growth and maintenance
Nutrients can be supplied in the field through the application of manure or fertilizer
C:N:P = (100-300):10:1
Requirements for Biodegradation
Proper nutrient balance Temperature 15 – 30 oCAcceptable pH 5.5 - 8.5Moisture content of 60% - 80% of
field capacityOxygen concentrationPresence of toxic heavy metals
Naphthalene Removal Efficiency
0
20
40
60
80
100
0 100 200 300 400
TIME (hours)
AV
ER
AG
E N
AP
TH
AL
EN
E
RE
MO
VA
L E
FF
ICIE
NC
Y (
%)
Non-Acclimatized Acclimatized Control
Bio-piles
Soil Composting
Hazardous Waste Landfill
Class I Landfill should include:
Double liner Leachate collection Leachate detection
system Surface water
control mechanism Impermeable cover
system
Hazardous Waste Landfill
Hazardous Waste LandfillLiner System
Regular Waste Landfill
Class II Landfill should include:
Single liner Leachate
collection Surface water
control mechanism Impermeable
cover system
Regular Waste Landfill
Solidification and Stabilization
The solidification and stabilization facility (SSF) will be designed to inactivate and immobilize contaminants prior to landfilling
Solidification and Stabilization
The following waste will be processed by SSF plant prior to landfilling:
Mercury contaminated solid wastes;
Solid miscellaneous inorganic sulfur;
Semi-solid hazardous waste; and
Sludge from Liquid Hazardous Waste Treatment
Solidification and StabilizationS/S reduces the mobility of hazardous substances and contaminants in the environment through both physical and chemical meansS/S seeks to trap or immobilize contaminants within their host medium (i.e. soil, sand and binding agent)Leachability testing is usually performed to measure the immobilization of contaminants from the stabilized matrix
Solidification and Stabilization
• General binding and sorbent materials: Cement Pozzolans Lime Silicates Organically
Modified Clays
High Temperature Thermal Desorption
HTTD is a technology in which wastes are heated to 320 to 560 oC Produce final contaminant concentration level below 5 mg/kg
Incinerator
Structure to house the furnace
Tipping floor where the Hazardous Waste is disposed
Storage pit to store the Hazardous Waste delivered
Charging system
Furnace
Air pollution control
Ash handling system
HWTC Control Philosophy
Provide a Supervisory Control and Data Acquisition (SCADA). The SCADA system will provide two levels of control:
Level 1 control operates equipment directly and bypasses all interlocks.
Level 2 is initiated directly by computer programming. Level 2 controls, operates equipment and processes remotely.
Typical Control System
Environmental Monitoring
Air Quality Groundwater
Quality Surface Water
Quality Dust and Noise
Environmental Monitoring
Selection of the parameters of concern
Sampling methodology
Quality assurance /quality control plan
Project Approach
Task 1: Review of Existing Data
Task 2: Discussion with Project Authority
Task 3: Development and Finalization of HWTF Design
Task 4: Prepare Final Design Drawings and Design Basis Memorandum
Project Approach (cont.)
Task 5: Design of Liquid Hazardous Waste Treatment Facility
Task 6: Class I and II Landfills Design
Task 7: Land Framing Facility Design
Task 8: Solidification and Stabilization Facility Design
Project Approach (cont.)
Task 9: HWTC Construction
Task 10: Facility Commissioning and Operation
Task 11: Facility Handing Over
Conclusions
1. Key to proper design of HWTC is system flexibility to adjust to hazardous waste quantities and properties over time
2. Enforcement of environmental law and regulations
Leachate Treatment Using Wetlands
Department of Environmental Engineering Beijing University of Chemical Technology December 2003
Wetlands
Wetland is define as land having the water table at, near or above the land surface or which is saturated for long enough period to promote wetland or aquatic processes as indicated by hydric soils, hydrophilic vegetation, and various kinds of biological activity which are adapted to the wet environment.
Treatment Mechanisms in a Wetland System
Type of Engineered wetlands
Constructed wetland systems are classified into
two general types: Horizontal Flow System (HFS)
Surface Flow (SF) Sub-surface Flow (SSF)
Vertical Flow System (VFS).
Horizontal Flow Wetland System
Surface Flow Wetland System
Subsurface Flow Wetland System
Field Monitoring
Monitoring wells
Pond #1
Pond #2Peat Filter
SW-1
SW-4SW-3
SW-2
DBA
C
FSW-1
FSW-2
FSW-3
W-2
W-1
MW-4
MW-1
MW-2
MW-5MW-3
Manhole
Pump
Field Monitoring
Boron Concentration
0
2
4
6
8
10
12
14
16
189
6-1
96
-2
96
-3
96
-5
96
-6
96
-7
96
-8
97
-1
97
-2
97
-3
97
-4
97
-5
97
-6
Monitoring Event
Co
ncen
trati
on
(m
g/L
)
Pond MW-A MW-B MW-C MW-D SW
Field Monitoring
Boron adsorption was directly related to organic content
Peat filter was effective in treating landfill leachate
The adsorption capacity of the peat can be significantly enhanced by lime addition
Conclusions