Simulation and evaluation of odor pollution from da phuoc landfills in ho chi minh city masters thesis major sciences and management of the environment

17 Table 1.2 Compsition of solid waste at Đa Phuoc and Phuoc Hiep landfill site .... 26 Table 1.5 Volume of solid waste collected at Da Phuoc landfill .... 81 Table 4.6 The composition o

THE JOINT ACADEMIC PROGRAM OF EXECUTIVE MASTER IN SCIENCES AND MANAGEMENT OF THE ENVIROMENT BETWEEN INDUSTRIAL UNIVERSITY OF HOCHIMINH CITY

AND LIÈGE UNIVERSITY

TA QUANG

SIMULATION AND EVALUATION OF ODOR POLLUTION FROM DA PHUOC LANDFILLS

IN HO CHI MINH CITY

Major: EXECUTIVE MASTER IN SCIENCES AND MANAGEMENT OF THE ENVIRONMENT

MASTER’S THESIS

HO CHI MINH CITY, YEAR 2018

To complete the master thesis topic, I would like to thank the school board, Graduate School of Ho Chi Minh City University of Industry, teachers Institute of Environment, together Teachers in various disciplines have enthusiastically taught and equipped me with knowledge during my studies

I would like to thank my advisor, Dr Luong Van Viet for his support and advice throughout this thesis I would also like to thank professor of university de liege for taught and supported me during my studies

Lastly but most importantly I would like to thank my parents for bringing me into this world and supporting me in every way possible Without them I would not be the man I

am today

Although there are many attempts to complete the topic But due to the early learning in scientific research, access to reality as well as knowledge is limited and lack of experience should not be avoided shortcomings I look forward to the comments of teachers and friends to complete the thesis

Author

Ta Quang

Odor,which refers to unpleasant smells, is nowadays considered an inportant

enviroment pollution issue Odor pollution abatement has involves a number of bodies

In this thesis, odor pollution in the inviroment will be reviewed, including its sources

and dispersion, the plysical and chemical properties of odor, odor emission from Da

Phuoc landfill in Ho Chi Minh city Determining the pollutant load from which the

intensity of the odor gas is calculated Simulate the spread of odor pollution and

evaluate to give the measures of reduction

Keyword: odor, odor pollution, olfactometry, pollution load (NH3, H2S,CH3SH), E- Gauss,Arcgis

TABLE OF CONTENTS

LIST OF TABLES 5

LIST OF FIGURES 8

LIST OF ABBREVIATIONS 10

INTRODUCTION 11

1 The reason for choosing the topic 11

2 Objectives of the study 12

3 Object and area of the study 12

4 The methodology 13

5 The meaning of the topic 13

CHAPTER 1 OVERVIEW OF THE FIELD OF THE STUDY 14

1.1 Overview of Ho Chi Minh City 14

1.1.1 Natural condition 14

1.1.1.1 Geography 14

1.1.1.2 Hydrogeology 14

1.1.1.3 Climate, weather 15

1.1.2 Social and economic conditions 15

1.1.2.1 Economic growth 15

1.1.2.2 Characteristics of population, society 15

1.2 Overview of domestic solid waste and solid waste management in HCM city 16

1.2.1 Situation of domestic solid waste generation 16

1.2.2 Volume and composition of the domestic solid waste 16

1.2.3 Current status of collection and transportation of the domestic solid waste 20

1.2.3.1 Collection time 20

1.2.3.2 Means of collection 20

1.2.3.3 Save at source 20

1.2.3.4 Collector at source 21

1.2.3.5 Collected at intended destinations (on the street) 22

1.2.3.6 Commercial Transfer Station 22

1.2.3.7 Transportation network 23

1.2.4 Purchasing and recycling of the solid waste 24

1.2.4.1 Reusing and recycling 24

1.2.4.2 Scrap collection facalities 24

1.2.4.3 Purchasing activity 25

1.2.5 Treating and landfilling of the domestic solid waste 26

1.3 Overview of Da Phuoc Solid Waste Treatment Complex 27

1.4 Components and process of forming foul odor gases from landfill sites 33

1.4.1 Components of odor gases from landfill sites 33

1.4.2 Process of forming gases from landfill site 34

1.4.3 Source causing foul odor from landfill sites 38

1.5 Method of assessment and odor meter 38

1.5.1 The nature of the odor 39

1.5.2 Measurement of odor by the olfactory sensitivity method 43

1.5.3 Measurement of odor by Electronic nose (E-nose) 45

1.5.4 Relationship between odor intensity and odor concentration 45

CHAPTER 2 RESEARCH METHOD AND CONTENTS 49

2.1 Situation of research on the spread of odor pollution 49

2.1.1 Abroad research situation 49

2.1.2 Domestic research situation 50

2.2 Research contents 51

2.3 Research methods 53

2.3.1 Statistical methods 53

2.3.2 GIS-RS method 53

2.3.3 Method of determining the intensity of odor 54

2.2.4 Method of determining the amount of odor pollutant load 55

2.3.5 Process of simulating odor pollution 62

CHAPTER 3 CHARACTERISTICS OF CLIMATE AND CIRCULATION IN HO CHI MINH CITY 65

3.1 Characteristics of climate in studied area 65

3.1.1 Rainfall 65

3.1.2 Temperature 68

3.1.3 Relative humidity 70

3.2 Wind speed and direction 72

CHAPTER 4 RESEARCH RESULTS AND DISCUSSION 76

4.1 Analysis of opinion survey 76

4.2 Garbage formula in Da Phuoc landfill site 80

4.3 The results determine the amount of odor gas 82

4.3.1 Loading of NH3 83

4.3.2 Loading of H2S and MER 87

4.4 Results of the odor intensity equation 92

4.5 The level of odor pollution around the landfill site through simulation results 93

4.3.1 The level of odor pollution through the dry season 93

4.3.2 The level of odor pollution through the rainy season 96

4.3.3 The level of odor pollution during the transition from dry to rainy season 99

4.4.4 The level of odor pollution during the transition from rainy to dry season 102

4.5 Proposing a plan to reduce odor pollution from the landfill site 105

4.5.1 Proposed scenarios 105

4.5.2 Analysis of pollution mitigation through scenarios 108

4.5.2.1 Scenarios 1 (Reduce 50% of the pollutant load) 108

4.5.2.2 Scenarios 2 (Reduce 50% of the pollutant load) 110

4.5.2.3 Scenarios 3 (Reduce 70% of the pollutant load) 111

4.5.3 Suggestions for reduction of pollution load 113

CONCLUSION & RECOMMENDATION 117

REFERENCES 118

APPENDIX 120

LIST OF TABLES

Table 1.1 Composition of solid wastefrom households, schools, restaurants and hotels in

Ho Chi Minh City 17

Table 1.2 Compsition of solid waste at Đa Phuoc and Phuoc Hiep landfill site 19

Table 1.3 Composition and volume of solid waste at purchasing and recycling facilities

25

Table 1.4 Domestic solid waste disposal and treatment plants are in operation 26

Table 1.5 Volume of solid waste collected at Da Phuoc landfill 31

Table 1.6 Componentsof gases from landfill sites by percentage by dry volume 33

Table 1.7 The effect of hydro sulfua gas on humans 39

Table 1.8 The effect of SO2 gas on humans 40

Table 1.9 The effect of NH3 gas on humans 41

Table 1.10 Scale of 4 on assessment of odor intensity 43

Table 1.11 Scale of 6 on assessment of odor intensity 43

Table 1.12 Odor threshold of H2S 46

Table 2.1 The value of k for tropical regions 59

Table 3.1 Average monthly rainfall in Tan Son Hoa station (mm) 65

Table 3.2 Monthly statistics of Tan Son Hoa station (0C) 68

Table 3.3 Monthly humidityof Tan Son Hoa station (%) 71

Table 3.4 Frequency of wind direction of Tan Son Hoa station (%) 73

Table 3.5 Average wind speed of Tan Son Hoa station (m/s) 74

Table 3.6 Average wind speed and standard deviation of Tan Son Nhat station 75

Table 4.1 Odor sign in the questionnaire 76

Table 4.2 Frequency of occurrence of odors over time in Nhon Duc commune (%) 79

Table 4.3 Frequency of occurrence of odors over time in Đa Phuoc commune (%) 79

Table 4.4 Composition of solid waste is capable of decomposing at Da Phuoc landfillsites 80

Table 4.5 The composition of domestic solid waste 81

Table 4.6 The composition of domestic solid waste in Da Phuoc landfill sites 81

Table 4.7 Data on NH3, H2S and MER emissions of Da Phuoc landfill site on average dry season and rainy season (tons/month) 83

Table 4.8 Coefficient k in calculated emissions of NH3 85

Table 4.9 The result of monthly and seasonal NH3 emission in Da Phuoc landfill site (ton/month) 87

Table 4.10 Coefficient k in calculated emissions H2S and CH3SH 88

Table 4.11 The results of average monthly and seasonal H2S emission at Da Phuoc landfill site (tons /month) 90

Table 4.12 The results of average monthly and seasonal CH3SH emission at Da Phuoc landfill site (tons /month) 91 Table 4.13 The results of H2S and CH3SH emission at Da Phuoc landfill in 2016 (mg/m2.h) 92 Table 4.14 Data on the concentration of odors and odor levels 92 Table 4.15 Frequency of occurrence of odors at the ward level during the dry season(%) 96 Table 4.16 Frequency of occurrence of odors at the ward level during the rainseason(%) 99 Table 4.17 Frequency of odors occurring at commune and ward levels during transitionfrom dry to rainy season (%) 102 Table 4.18 Frequency of odors occurring at commune and ward levels during transition from rainy to dry season (%) 105 Table 4.19 Frequency ofl odor in communes with Scenario 0 (%) 108 Table 4.20 Frequency of level odor with KB 1 and the decrease compared to KB 0 (%) 109 Table 4.21 Frequency of level odor with KB 2 and the decrease compared to KB 0 (%) 111 Table 4.22 Frequency of level odor with KB3 and the decrease compared to KB 0 (%) 112

LIST OF FIGURES

Figure 1.1 Da Phuoc Solid Waste Treatment Complex 27

Figure 1.2 The system of reservoirs and leachate treatment 30

Figure 1.3 Olfactometry 42

Figure 1.4 Relationship between odor concentration and odor intensity of Butanol and Hydrogen Sulphide 47

Figure 3.1 Average surface temperature of Tan Son Hoa station (oC) 69

Figure 3.2 High temperature on Tan Son Hoa station (oC) 70

Figure 3.3 Average humidity of Tan Son Hoa station, 2 m height (%) 71

Figure 3.4 Wind at 10m in Tan Son Hoa station 72

Figure 3.5 The prevailing wind speed and average wind speed of Tan Son Nhat station

74

Figure 3.6 Wind direction and average wind speed on the elevation of Tan Son Hoa station 75

Figure 4.1 Percentage of time people live in their current place of residence 76

Figure 4.2 Odor sensitivity level 77

Figure 4.3 Feel about the characteristic odors 79

Figure 4.4 Relationship between monitoring data and NH3 emission calculation 86

Figure 4.5 Relationship between monitoring data and calculation of H2S emission 89

Figure 4.6 Relationship between monitoring data and calculation of CH3SH emission

90

Figure 4.7 Frequency of first class odor in dry months 94

Figure 4.8 Frequency of third level odor in dry months 94

Figure 4.9 Frequency of secondary level odor in dry months 95

Figure 4.10 Frequency of fourth level odor in dry months 95

Figure 4.11 Frequency of first class odor in the rainy season (%) 97

Figure 4.12 Frequency of third class odor in the rainy season (%) 97

Figure 4.13 Frequency of secondary class odor in rainy season (%) 98

Figure 4.14 Frequency of fourth class odor in the rainy season (%) 98

Figure 4.15 Frequency of first level odor in the transition months from dry to rainy season (%) 100

Figure 4.16 Frequency of first level odor in the transition months from dry to rainy season (%) 100

Figure 4.17 Frequency of third level odor in the transition months from dry to rainy season (%) 101

Figure 4.18 Frequency of fourth level odor in the transition months from dry to rainy season (%) 101

Figure 4.19 Frequency of first level odor in the transition months from rain to dry

season (%) 103

Figure 4.20 Frequency of second level odor in the transition months from rain to dry season 103

Figure 4.21 Frequency of third level odor in the transition months from rain to dry season (%) 104

Figure 4.22 Frequency of foutth level odor in the transition months from rain to dry season (%) 104

Figure 4.23 Frequency of second level odor with Scenario 0 (%) 107

Figure 4.24 Frequency of third level odor with Scenario 0 (%) 107

Figure 4.25 Frequency of second level odor with Scenario 1 (%) 108

Figure 4.26 Frequency of third level odor with Scenario 1 (%) 109

Figure 4.27 Frequency of second level odor with Scenario 2 (%) 110

Figure 4.28 Frequency of third level odor with Scenario 2 (%) 110

Figure 4.29 Frequency of third level odor with Scenario 3 (%) 111

Figure 4.30 Frequency of third level odor with Scenario 3 (%) 112

Figure 4.31 Vertical wells 116

Figure 4.32 Horizontal wells 116

LIST OF ABBREVIATIONS

Department of Labor

INTRODUCTION

1 The reason for choosing the topic

In the strategy of industrialization and modernization of the country by the Party and the Government set out and by the National Assembly through in the strategy for socio-economic development, 10-year period from 2011 to 2020, important goal is to develop faster and stronger to increase the contribution of the industry, construction and services

in the economy structure [1] The manufacturing business service in urban areas; industry zones (IZ) have increasingly expansion and development has spurred the growth of the economy - society Economic growth - social contribute positively to the development of the country, on the other hand gave increase to solid waste (SW) and more (include municipal solid waste, industrial solid waste, medical solid waste, ) The disposal indiscriminate and the lack management of uniformity of the authorities, is one of the causes of environmental pollution, spread of diseases, affecting the health and human life

Our country is one of the countries with the highest population density in the world with

a population ranks 3rd in Southeast Asia, 14th in the world The process of rapid population growth led to demands for housing, healthcare, transportation, increasing pressure on the natural environment and social environment Load capacity of the natural environment is limited, when the amount of waste not been disposal increase being discharged into the environment would exceed the self-cleaning ability of the natural environment, cause environmental pollution Municipal solid waste mainly domestic solid waste accounting for about 60-70% of the solid waste generated, followed by the construction of solid waste, industrial solid waste, medical solid waste, The collection rate of domestic solid waste, services and industries today has increased significantly in urban areas is 83-84%, however not meet the actual needs Beside, the majority of domestic solid waste had unclassified and transported to landfills It is this that the disposal of solid waste in Vietnam living complex than advanced countries Therefore, the solid waste is one of the main reasons, pollute surface water, air, soil,

urban landscape and the adverse impact on the community This time, separately in Ho Chi Minh City receiving more than 7,500 tons of solid waste / day, which makes the landfills become overloaded and not guaranteed to be the issues related to the environment The solution for the management of landfills just focus on the problem of leachate, collapse or subsidence, groundwater The study on air pollution has formed the foundation but have not been applied in practice Especially odor pollution, the problem is not interested in the EIA report, The annual environmental report So, when planning the landfill sites were met with opposition from people around

From these issues, topic: "Simulation and evaluation of odor pollution from Da Phuoc landfills in Ho Chi Minh City" to be studied in order to make the assessment, long-term solution to the problem of odors from the landfill sites in the city

2 Objectives of the study

2.1 General Objective

Applying simulation software spreads the odor pollution from the Da Phuoc landfill activities serve tge assessement, planning and management of solid waste

2.2 Spectific Objectives

Determine the natural conditions, terrain meteorological survey area

Odor level determination based on the components related pollution for assessing pollution levels and simulated smells odors

Determine the load of pollutants related to odor and serving smell spread simulation Applying the model to spread the smell: Mapping the spread of odor simulation based

on odor pollution levels

3 Object and area of the study

3.1 Objectives

- Odor pollution from Da Phuoc landfill

- Model of odor diffusion in the air

- Areas affected by odor arising from Da Phuoc landfill

- Method of determining the intensity of odor

- Method of determining the amount of odor pollutant load

5 The meaning of the topic

5.1 Scientific significance

The research was based on the scientific basis, approaching the object through investigation, survey and analysis, and then assess the extent of odor spread at the Da Phuoc landfill to the residential areas surrounding the landfill site and propose appropriate solutions for mitigation and protection of the environment

5.2 Practical significance

The study was conducted to assess the spread of odor pollution and to propose remedies and mitigation measures This will create favorable conditions for industrial and agricultural production of people in the area and ensure the living of people in the area surrounding the Da Phuoc landfill

CHAPTER 1 OVERVIEW OF THE FIELD OF THE STUDY

1.1 Overview of Ho Chi Minh City

1.1.1 Natural condition

1.1.1.1 Geography

Coordinating location of Ho Chi Minh City:

- North latitude: 10°10' – 10°38' North

- East longitude: 106°22' – 106°54' East

Ho Chi Minh City is located in the south-eastern region of Vietnam, 1,760 km (1,090 mi) south of Hanoi The average elevation is 19 metres (62 ft) above sea level It borders:

- The north borders with Tây Ninh Province and Bình Dương Province;

- The east borders with Đồng Nai Province and Bà Rịa–Vũng Tàu Province ;

- The west borders with Long An Province ;

- The south borders with The East Sea;

With its central location in Southeast Asia, Ho Chi Minh City is an important transport hub for both land, water and air, connecting the provinces in the region and also as an international gateway.[1]

1.1.1.2 Hydrogeology

Geology of Ho Chi Minh City consists mainly of two generations of Pleistocene and Holocene sediments exposed on the surface Pleistocene sediments occupy most of the North, Northwest and Northeast of the city Under the influence of natural factors and human activities, alluvial sediment formation forming specific soil group: gray soil With more than 45 thousand hectares, or about 23.4% of the city, the gray soil in Ho Chi Minh City has three types: gray soil, gray soil with reddish-brown and reddish-gray soil.[2]

On hydrography, Ho Chi Minh City located in the downstream of Dong Nai river

system - Sai Gon Ho Chi Minh City have many different rivers and canals Dong Nai River originates from the Lam Vien plateau, confluence with many other rivers, with large basins, about 45,000 km² With an average flow of 20-500 m³/s, annually provides

15 billion m³ of water, Dong Nai River becomes the main freshwater source of the city The Saigon river originates from the area of Hon Quan district, flowing through Thu Dau Mot to Ho Chi Minh City It has a length of 200 km and runs along the city about 80 km.[3]

1.1.1.3 Climate, weather

Located in the tropical savanna, Ho Chi Minh City has only two seasons: rainy season – dry season The rainy season starts from May to November (hot and humid climate, low temperature, heavy rain), and dry season from December to April next year (dry climate, high temperature and low rainfall) Average, Ho Chi Minh City has 170 to 275 hours of sunshine per month, average temperature is 28.7 °C, highest temperature is

32 °C, lowest temperature is 25 °C Every year, the city has 330 days average temperature 25-28 °C Average rainfall of the city reached 1,760 mm/year.[4]

Ho Chi Minh City is affected by two main winds are the southwest monsoon - southwest and north - northeast West-Southwest wind from the Indian Ocean, average speed is 3.6 m/s in rainy season North-East wind from the East Sea average speed 2.4 m/s in the dry season There is also a south-southeastern trade wind around March to May, average speed is 3.7 m/s It can be said that Ho Chi Minh City is not a wind storm

1.1.2 Social and economic conditions

In 2016, the average population in HCMC estimated to be 8.426,1 thousands of people,

an increase of 2.16% over 2015 [6] The distribution of people in HCMC is uneven While districts such as districts 4, 5, 10 and 11 have a density of over 40,000 persons/km² and Can Gio district has a relatively low population density of

98 persons/km² In recent years, The population of central districts tends to decrease, while the population of new districts is rising rapidly Estimated in 2005, there are about

1 million visitors per day in HCM City By 2015, this figure could increase to 2 million.[7]

1.2 Overview of domestic solid waste and solid waste management in HCM city

1.2.1 Situation of domestic solid waste generation

Ho Chi Minh City is a large urban area with high annual domestic solid waste generation The volume of domestic solid waste generated in HCMC is shown in Table 1.1 According to this table, the volume of municipal solid wastes is rather highthe average annual increase in the period 2000-2015 is 7.22%

According to the Department of Natural Resources and Environment, total volume of daily-life waste arising in HCM city is estimated at 7,500 - 8,000 tons/day ( 2,7-2,9 million tons/year) With the volume of collection and transportation to the landfill about

7000 – 7.200 tons/day, the rest is solid waste for recycling Only a small part, mainly organic waste discharged to the field in the suburbs Comparisons of the volume of daily-life solid waste generated are calculated according to the population figures coefficients of solid wastes (kg/person) and the volume of solid wastes are collected and processed by weighing stations at solid waste treatment complexes over the years showed: The rate of collection and treatment of domestic solid waste is approximately 85% in 2014, 85,3% in 2015 and 100% in 2016.[8]

1.2.2 Volume and composition of the domestic solid waste

Domestic solid waste generated mainly from the following sources: residential area, commercial area, offices, hospital, schools, construction, public works, factory, agricultural activities Composition of domestic solid waste at sources such as

household, schools, restaurants, hotels in HCMC is analyzed in table 1.1

Table 1.1 Composition of solid wastefrom households, schools, restaurants and hotels in

Ho Chi Minh City[9]

- “-“ – Unknown

Households: Composition of solid waste accounted for most of is the food (The average value on the sample is 61 – 96 %), Nylon (0,5 – 13,0%), nhựa plastic (0,5 – 10,0%), paper (0,7 – 14,2%), glass (1,7 – 4,0%), fabric (1,0 – 5,1%), debris and leaves (1 – 2%), can (0,98 – 2,30%), wood (0,7 – 3,1%) [9] Special, Carton hardly appears in samples of solid waste from households Data on solid waste composition of households showed that although households now classify waste for reuse but the waste can be recycled still much However, most recyclable components are often contaminated and have high humidity

Schools: Data analysis of solid waste generated from the school shows components garbage can recycle a high percentage, ssuch as nylon (8,5 – 34,4%), plastic (3,5 – 18,9%) and paper(1,5 – 27,5%) [9] The percentage of components varies depending on the student's grade level and mode of activity (boarding school, day-boarding school )

In the solid waste samples were analyzed activities in schools, The highest percentage

of food waste at boarding schools occupy (23,5 – 75,8%), The other schools have smaller proportions (23,5 – 32,5%) [9] In addition, when comparing the percentage of solid waste discharged from schools compared to households and markets, day-boarding schools have the same percentage of solid waste as those of the household

Restaurants, Hotels: Depending on the size and management, composition of solid waste of the restaurant and the hotel varies greatly For the hotels with large size or restaurants almost all solid waste has been classified before being discharged While hotels are small in size, solid waste has most of the household components

At the source, Solid waste is usually "clean”, easy to classify and collect, low humidity (excluding food solid wastes) The major component of solid waste at landfill sites is food waste at a relatively high rate (83,0 – 88,9% ww) Composition of soil waste can recylable such as plastics, paper, metals are significantly reduced by classification and scrap collection The rest is less recyclable, mostly inorganic (sludge, soil)

Table 1.2 Compsition of solid waste at Đa Phuoc and Phuoc Hiep landfill site[9]

0,1 – 0,2%, The cause is due to the separation activities (outside the house) to collect valuable scrap This work is picked up by scavengers, collecters from waste sources and scrap collecter at rendezvous and Commercial Transfer Station

1.2.3 Current status of collection and transportation of the domestic solid waste

1.2.3.1 Collection time

The work of cleaning and gathering on the street today is mainly done at night, Working time starts from 18 to 22 hours and ended before 6 am the following morning However, for some central districts (district 1, district 3, district 10, .) are arranged throughout the day to ensure the maintenance of the quality of street cleaning

1.2.3.2 Means of collection

Collection means is being invested in the direction of safety, modern However, there are still some rudimentary means of collection with small quantities and most concentrated in Binh Chanh district, the amount of dustbin (660 l capacity) for solid waste is only 69% In addition, some districts such as Districts 4, 9, Phu Nhuan, Go Vap, Cu Chi still use other means available for cleaning and moving However, because these means do not ensure sealing and often spills contaminated waste so districts are still actively investing and converting their means of collection to dustbin 660 liters to ensure street hygiene, labor safety and traffic safety

1.2.3.3 Save at source

Solid waste is not currently classified at the source Households use plastic dustbin for containing solid waste, others use metal dustbin or bamboo baskets Most commonly, people use nylon bags that contain solid waste and put them in dustbin At the time of solid waste collection, households bring dustbin or dustbin bags to the front door so that collectors can easily collect them For those who are not home at the time of collection, solid waste is often put in tightly packed dustbin bags, in front of the door

At the market, due to the limited business area, most small traders are making full use of space as storage space very few places have dustbin , Most of the generated solid waste

is disposed of in the market aisles After the market, the sanitation workers will collect solid substances in the market For schools, offices, restaurants, hotels, solid waste is stored in small dustbin are equipped in the unit After that, most of the soil waste was delivered to dustbin 240L

1.2.3.4 Collector at source

Today in HCMC, solid waste is collected through the following three forms:

Form 1: daily, solid waste are collected by dustbin trolleys and gathered at the indicated destination, and then solid waste from the dustbin trolleys will be poured into small compactor trucks (from 2-4 tons) and transferred to the Commercial Transfer Station

At the Commercial Transfer Station, large trucks pick up solid waste from small garbage compactor trucks and transport them to the landfill site

Form 2: Solid waste are collected by dustbin trolleys and gathered at the indicated destination, then solid waste from the dustbin trolleys will be poured into compactor trucks (or large garbages compactor system) and transported directly to landfill site This technology is being used and increasingly expanded to reduce the destinations concentrating too many solid waste and to restrict pollution

Form 3: Solid waste available in dustbin (240-600L) along the roads or at large sources

of waste (markets, commercial areas, offices ) are poured into small compactor trucks (from 2-4 tons) and transported to the Commercial Transfer Station At the Commercial Transfer Station, large trucks pick up solid waste from small compactor trucks and transport them to the landfill site In this form, if the solid waste from the dustbins are poured into the large compactor trucks, the trucks will transport them straight to the landfill site

Domestic solid waste collection activities in the city are carried out by 03 groups of units: (1) the public system operated by Urban Environment Company and 22 District Public Service Companies (Tan Phu and Binh Tan districts are newly established so that they have no public service company), now all of these companies have been

transformed into one-member limited liability companies; (2) the private system run by the private solid waste collection force, which is located outside or in about 30 collecting syndicates and (3) solid waste collection cooperatives (District 2, District 4, District 6, Go Vap District, Thu Duc District) [9]

The statistics show:

60% of the volume of solid waste generated from households due to the private solid waste collection force, 40% due to solid waste collection cooperatives and public service companies There are 4.000 collectors in the private solid waste collection, and 1.500 collectors in solid waste collection cooperatives and public service companies

1.2.3.5 Collected at intended destinations (on the street)

Currently in Ho Chi Minh City, there are 241 intended destinations, mainly in districts such as Tan Phu (76 destinations), District 10 (41 destinations), District 8 (17 destinations) that are inner districts in the city, the rest are scattered in some districts The number of existing intended destinations (in 2015) are greatly reduced compared to period of 2005-2010 The locations of the intended destinationsare frequently displaced due to poor environmental sanitation This will affect the beauty and traffic of the city

1.2.3.6 Commercial Transfer Station

Currently in HCMC, there are 45 commercial transfer stations with the task of concentrating the amount of solid waste from private solid waste collection force, cooperatives, companies At the commercial transfer station s, solid waste are picked up large trucks and transported to the landfill site (10-15 ton/car)

The commercial transfer station s are divided into 4 categories:

Type 1 :

- Large reception capacity of over 800 tons /day

- The workshop is designed to meet the requirements, large campus

- Technology: hooklif facilities, environmentally controlled, leaked water collection system

Type 2:

- Small receiving capacity: 20 - 100 tons /day

- Applied technology is the hooklif facilities

- The commercial transfer station has wall surrounding, a security gate, a roof, a

cement floor, a leaking water collection system

Type 3:

- The commercial transfer station has wall surrounding, with guard, with / without roof, cement floor, with / without leachate collection system

- Means of transportation closed

- Capacity : over 100 tons/day

Type 4:

- The commercial transfer station has wall surrounding, no guard gate, with/ without roof, cement floor, without leachate collection system

- Means of transportation closed

- Capacity: less than 100 tons/day

Currently, the total of 45 commercial transfer station and garbage dumps, there are 33 commercial transfer station of type 3 and 4 This is an open commercial transfer station

or open rubbish dumps (73%) Therefore, it is necessary to invest in replacing open rubbish dumps into closed rubbish dumps with advanced technology In addition, it is necessary to build a substation with a waste recycling station

1.2.3.7 Transportation network

The solid waste transportation network from the intended destinations to the landfill sites is carried out by 3 units: HCMC Urban Environment Company Limited (53%), District Public Service Companies (30%) và Cooperatives (17%)

Form of execution: the existing districts (District 1, Tan Binh District, Binh Chanh District, Cu Chi District, Can Gio District) and two newly established districts carry out the bidding (Tan Phu District, Binh Tan District), which received funds from District

People's Committee The remaining districts will be executed by HCMC Urban Environment Company Limited, District Public Service Companies and Cooperatives City People's Committee assigned Urban Environment Company Limited as a unit main contractor, which signed contracts with the remaining units

Transportation: including motor vehicles of all kinds (garbage trucks, trucks, excavators) In particular, the number of vehicles used for solid waste collection and transportation from the intended destinations or commercial transfer station to the landfill sites are 261 vehicles

Statistics also show that about 55% of solid waste transportation vehicles have a leachate collection system, which made sure the leachate does not leak out But, the remaining vehicles have not a leachate collection system There are still a large number

of vehicles that do not guarantee the environment is still functioning

Average distance of transportation of domestic solid waste of Ho Chi Minh City on the landfill sites (Northwest and Da Phuoc complexes) as follows: Phuoc Hiep 47.66 km;

Da Phuoc 29.08 km; Vietstar 50.17 km

1.2.4 Purchasing and recycling of the solid waste

1.2.4.1 Reusing and recycling

Currently, recyclable solid waste is collected by scrap collectors These types of solid waste come from the daily activities of households, offices, factories, commercial centers, garbage dumps Most of scrap collectors are small, backwar so it is not possible

to create high quality products

1.2.4.2 Scrap collection facalities

According to the survey of 202 scrap collection facalities, most the scrap collection facalities have to rent premises to do business Of the surveyed in 202 scrap collection facalities, 178 ones (78.2%) [10]haveto rent premises And most the scrap collectors’s areas are small or very small There are only a few ofthe scrap collectors(4.5%) with large areas (several hundred of m2) and many workers (from 6 people or more)

1.2.4.3 Purchasing activity

In 202 scrap collection facalities always buy scrap materials such as plastic, paper, plastic, glass, copper, aluminum, iron These scrap collection facalities mostly purchase scrap from collectors And there are facilities that only purchase liquidated and scrap materials from the factory

Table 1.3 Composition and volume of solid waste at purchasing and recycling facilities

[10]

(tons/month)

Recycling volume (tons/month)

The majority of workers in recycling facilities have a low level of education according

to a survey of 202 recycling facilities, about 80% of them have secondary education) so this will be difficult to apply new technology for recycling industry

In order to effectively manage this system, the city needs to prepare a land fund to relocate these facilities, and at the same time, it must create a fund to support technology innovation and improve its scale

1.2.5 Treating and landfilling of the domestic solid waste

By the end of 2015, urban solid waste treatment will be fully funded by domestic and foreign capital Current solid waste treatment technologies are landfilling (85% by volume) and composting (15% by volume) Cities are calling for investment in new processing technologies such as solid waste incinerators

Table 1.4 Domestic solid waste disposal and treatment plants are in operation[9]

Capacity (tons/ day)

Since the end of 2007, the city has secured the reception and handling of all solid waste

in the city, to create conditions for searching and applying new technologies (production compost, burning gas generators, production of building materials, …) To manage the process of recycling, reusing and reducing waste volumes to landfills in order to effectively use land However, the volume of solid waste is increasing so cities need to plan technology orientation in order to save land fund and at the same time identify

areas for future solid waste treatment Management must be consistent with the policy

of the state and ensure order and security in solid waste management

1.3 Overview of Da Phuoc Solid Waste Treatment Complex

Da Phuoc Solid Treatment Complex is located in the South of HCM, which belonging

to Hamlet 1 and 2 of Da Phuoc Commune, Binh Chanh District:

- The north borders with Rach Chieu River;

- The south borders with Ba Dinh intersection;

- The south borders with Ba Lao canal;

- The west borders with Nga Cay canal

Figure 1.1 Da Phuoc Solid Waste Treatment Complex [11]

This complex was built on semi-desert wet soils in Da Phuoc Commune, Binh Chanh District, Ho Chi Minh City

Da Phuoc Waste Treatment Complex was started in July 2005 The complex is owned

by Vietnam Waste Solutions (VWS) company responsible for construction design and operation Total capital investment will exceed US$ 100 million The founder of VWS,

Mr David Duong who is a Vietnamese-American and also Chairman and CEO of California Waste Solutions, Inc., (CWS), California, US

CWS is currently the 37th ranked waste management company on the top 100 list by

Waste Age magazine The project covers an area of 138 hectares, divided into four phases, operating for 24 years Phase 1 of the project is a landfill area of approximately 30.6 hectares and approximately 3 million m3 of airspace This is a landfill site built in accordance with a class II landfill, as defined by California Regulations

Phase 1 has a design capacity of 12.000 tonnes per day and current treats 3,000 tonnes per day for Hochiminh City and 20 tonnes per day for Long An

The project also includes ancillary facilities, which are located in the north-west corner

of the property limits, and bordered by canals to the north and west The facilities area is approximately 15 hectares in size Ancillary facilities at the DPIWMF include: Access bridge; guard house; Scale house-Weighstation; Material recycling facility (MRF); Commercial Transfer Station; Composting area; Employee Canteen; Administrative buildings; Equipment Maintenance Facility; Fuel Depot; High Voltage/ Low Voltage Switchroom; Water Supply and Fire Water Systems; Leachate Storage Ponds; Leachate Treatment Facility – with Multipe Treatment Processes; Landfill Gas to Electricity Facility

DSW is collected to the commercial transfer station, after passing the weighbridge will

be poured at the floor to check the garbage Through inspection (mainly by the senses),

if detecting garbage not or not allowed to bury will be transported to other disposal places as prescribed The types of garbage allowed to be buried will be excavated from the floor to the specialized trucks, transported to the garbage box

Landfill sites are lined with sand, clay, HDPE plastic sheets and PE pipes are installed

to collect leachate At each garbage dumps, the garbage is leveled in layers of not more than 60cm in thickness (to achieve max) and compacted by special vehicles Landfill Compactor 826G CAT (number of compaction times 6-8 times through 1 point) to ensure the minimum density after compaction is 0.75 tons/m3 [11]

After each day of receiving garbage, the thickness of waste after compaction of 2.2 m will be covered with an intermediate layer of 15cm thick (has been compacted) After that, the trucks is used to transport land from the reserve (500m) to the landfill and a

bulldozer is used to level ground in the landfill, which creating rain water drainage slope Each Landfill sites will be filled with 9 layers of garbage (each thick layer is 2.2m thick) The last garbage will be completed in the order: clay thick layer is 30cm; HDPE plastic thick layer is 1,5mm; sand layer thick is 20cm; top soil thick is 80cm to plant trees

The slope from the foot to the top of the landfill site increases from 3-5% to ensure good drainage and not slip or subsidence In the course of landfilling garbage, it will be paved with filter stones, put vertical pipes to collect gases from the landfill Gas hoses

in horizontal direction will be connected to these vertical pipes conducting to the treatment plant The garbage collectorsare sprayed with EM and EEM bio-preparations during the time of receiving garbages and additionally sprayed at night

Material recycling facility : The 15,168 m2 (96 x 158m) building will contain the sorting and separating facilities for recycling The MRF facility can receive and process over

500 tons/day of select material separated from the incoming refuse Based on similar MRF designs in the United States, the building includes access for different waste streams and multiple outgoing recycled products With mentioned Transfer Station, this building is currently the largest building in Vietnam constructed without columns in the middle

Currently, VWS runs tests with capacity of 100 tons/day Composting will utilize a closed bag and blower process which will eliminate odor during operations After the commission, the capacity will be increased to 1.000 tons/day

Leachate Storage Ponds : Two leachate storage ponds provide leachate storage prior to treatment The allotted area for the leachate storage pond is approximately 2.4 ha (110

m by 225 m), and have a combined holding capacity of 26,000 m3

Leachate Treatment Facility: Phase 1: Water Treatment Plant is a reverse-osmosis process capable of treating over 280 m3/day meeting all Vietnamese discharge standards This technology is firstly applied in Viet Nam for leachate treatment purpose Phase 2: Water Treatment Plant is a chemical dosing filtration process currently treating

3,000 m3/day Phase 3 Treatment: this 1,000 m3/day process with utilize a Membrance Bio-Reactor Process This technology is firstly applied in Viet Nam leachate treatment purpose

Figure 1.2 The system of reservoirs and leachate treatment [11]

Water treatment system is the aerobic treatment system mainly by activated sludge (USB), the pre-treatment stage usesphysical and chemical method Waste water after being treated and tested reaching to discharge standards (Class C) shall be discharged into the watercourse surrounding the landfill site

Da Phuoc landfill is advertised as a very modern American technology, especially in the treatment of foundation, waterproofing and minimizing odor However, after being put into use, VWS said that because Ho Chi Minh City does not organize waste classification at the source, garbage can not be recycled or produced as compost as originally planned

In 2007, People's Committee of Ho Chi Minh City approved the Urban Environment Company Limited to build the landfill site No 3 in Phuoc Hiep and Cu Chi Waste Treatment Plant By September 2013, the landfill No 3 came into operation, receiving

about 2,000 tons of garbages per day, up to 2022 the site will be closed

In June 2014, People's Committee of Ho Chi Minh City issued Document No 475 directing Urban Environment Company Limited to work out the plan to close the landfill site No 3 of the Phuoc Hiep landfill site

On October 17, 2014, the Committee continued to send document No 5363 to the Party Committee of Ho Chi Minh City on the closure of landfill site No 3 and transferring domestic wastetoDa Phuoc Solid Waste Treatment Complex with the reason “the landfill technology is in danger of causing pollution” Executing the request of the city government, by the end of November 2014, each day, the company received an additional 2,000 tons of garbage from Ho Chi Minh City Urban Environment Company

In order to do this, VWS invested in new equipment, expanded water treatment plants and recruited more workers Accordingly, the level of waste treatment of Da Phuoc from 3,000 tons per day increasing to 5,000-5400 tons per day and the landfill site area until the end of 2016 was nearly 46 ha

Table 1.5 Volume of solid waste collected at Da Phuoc landfill[11]

Year Volume of solid

Up to now, scientists have reserved their views on the limitations of Da Phuoc landfill,

especially in terms of location In the planning, Ho Chi Minh City is developing urban

to the southeastin District 7, Nha Be but placing a large landfill site at the beginning of the wind direction HCM city is a large city with the expression of the tropical heat island effect to be quite strong, at noon, the 2m level air temperature in the central area may be 1-2oC higher than the suburban area Due to the proximity of the sea and the buffersurface is burned, the mainland winds in this area exist around the year with the main wind direction of SE With this direction, a part of District 7, densely populated areas of communes in the surrounding areas will be affected Moreover, this is a landfill that allows the landfilled height to be quite large Currently, this landfill site has reached

a height of 25m and will reach the standard height of 40m under the new design The large height of the landfill site will facilitate the spread of pollutants going further, affecting the high buildings in District 7, Nha Be and Binh Chanh

“Research on the construction of emission factors of polluted gases from domestic solid waste landfill site”carried out by Mai Thi Thu Thao et al., shows that the emission of foul odor gases on Da Phuoc landfill site is rather high The current annual emission factor of NH3 is 148.75 mg/s.ha; H2S is 62.21 mg/s.ha; CH4 is 1,096.05 mg/s.ha and Mercaptan is 18.79 mg/s.ha.[12]

Currently, the areas surrounding Da Phuoc landfill site are heavily polluted by the operation of landfill site such as transportation and landfill During the 10 years of operation, people in Da Phuoc and neighboring communes have repeatedly submitted their recommendations on the environmental pollution surrounding Da Phuoc landfill Bad stinking situation and water pollution make people unable to grow rice,

aquaculture, affect people’s health

Odor pollution not only occurs in the vicinities of the Da Phuoc solid waste treatment plant but also affects the Saigon South The objects that are suspected of causing foul ordor are the factories located in Da Phuoc Solid Waste Treatment Complex, including: Green Biotech Sai Gon Co ltd., Hoa Binh Urban Environmental Service Company and

Da Phuoc solid waste treatment plant By the end of August, there has been no unit admitted the foul ordor attacking Saigon South caused by them Leader of HCMC People's Committee Office said that after organizing inspection delegations: “the City determined that foul ordor attacking residential areas in District 7, Binh Chanh, Nha Be was from the landfillsite receivinggarbages and Leachate reservoir of Da Phuoc landfill”

1.4 Components and process of forming foul odor gases from landfill sites

1.4.1 Components of odor gases from landfill sites

Landfills are a source of biogas including: NH3, CO2, N2, CO, H2S, CH4…, in which

CO2 accounts for 33.6%, CH4 accounts for 63.8% In addition, the gas composition of landfill sites also contains a number of different gases such as hydrocacbon (CH2), bezen (C6H6)… in landfill conditions stable performance from 1-2 years Major odors from landfill sites include NH3 and sulfur compounds such as H2S, Methyl Mercaptan According to Tchobanoglous, the composition of the gas from the landfill site is expressed as a percentage of dry volume as in table 1.6

Table 1.6 Componentsof gases from landfill sites by percentage by dry volume[13]

Organic + O2 + Nutrients New cell + CHC hard to decay +

CO2 + H2O + NH3 + SO42- +…+ Q

organisms

1.4.2 Process of forming gases from landfill site

The process of forming gases from landfill sites occurs through 5 stages: aerobic decomposition, anaerobic decomposition, acid fermentation, methane fermentation and stablility phases.[14]

Stage 1: Aerobic decomposition

This stage may last from a few days to several months, depending on the decomposition rate During this stage, the organic components are decomposed under aerobic conditions by the amount of air trapped in the disposal siteduring landfill The major source of microorganisms carrying out the waste disintegration process in the soil that is used as the covering material, is present in the organic component of garbage right from the moment the garbage is collected

The aerobic biological metabolism of solid waste can be generalized in the following

The gases produced during this process are mainly CO2 and NH3 A part of NH3produced by the oxidation of organic compounds is further oxidized to nitrate (nitrification) The oxidation of NH3 to nitrate can be calculated by the following equation:

NH3 + 3/2O2 HNO2 + H2O

HNO2 + ½ O2 HNO3

or NH3 + 2 O2 H2O + HNO3

Stage 2: Anaerobic decomposition

When the oxygen in the garbages is exhausted, the decomposition is transformed into anaerobic one The anaerobic decomposition of solid waste in the landfill site is as follows:

Once the landfill site beginstransforming to anaerobic decomposition, nitrates and sulfates (elesolid wasteon acceptors in bioremediation reactions) are often deoxidized to nitrogen gas N2, H2S and CH3SH With reduced oxidation, the microbial community performs the hydrolysis and metabolism of polymeric compounds (lipids, polysaccharides, proteins, nucleic acids) by intermediates into simpler compounds that are suitable for microorganisms Microorganisms use these simple compounds as the source of energy and carbon for their cells During this period, the pH of the leachate will decrease due to the formation of organic acids and the effect of the increase in CO2concentration in the landfill site

Odors arise when the solid wastesare stored for a long time at the intended destinations, Commercial Transfer Station transfer stations, and landfill sites In hot, humid climate areas, the rate of odorgenerating is high The formation of odor is the result of anaerobic decomposition of organic components in the garbage Under anaerobic conditions, sulphate SO42- can be decomposed into sulfur S2- and S2- will combine with H+ to form

a compound with the smell of rotten eggs as H2S The H2S formation is the result of two chemical reactions

2CH3CHOHCOOH + SO42- 2CH3COOH + S2- + 2H2O + 2CO2

Organic + H2O

organisms

Micro-New cell + CH4 + CO2 + Other biodegradable gas

4H2 + SO42- S2- + 4H2O

S2- + 2H+ H2S Ion Sunphide (S2-) can also be combined with metal salts such as iron to form metal sulphides

S2- + Fe2+ FeS Leachate at the landfill is black due to the formation of sulfuric salts in anaerobic conditions Therefore, without the formation of sulfuric salts, the formation of odor at the landfill site is a serious environmental problem The biochemical degradation of sulfur-containing organic substances can produce strong-smelling substances such as methyl mercaptan and aminobutyric acid:

Metyl mercaptan may be formed by biochemical hydrolysis metanol và hidro sunphua

CH3SH + H2O  CH3OH + H2S

Stage 3: Acid fermentation

In this stage, the transformation of the compounds formed in the above steps takes place into intermediates of low molecular weight such as acetic acid CO2 is the principal gas formed during this period, a small amount of H2, H2S is also formed The activemicroorganisms in this stage are mostly arbitrary and aerobic The pH of the leachate will decrease to value <5 due to the presence of organic acids and CO2 in the landfill BOD5, COD and conductivity increase considerably throughout this period due

to the dissolution of organic acids into the leachate Because of the low pH of the leachate, some inorganic components, mainly heavy metals, will be dissolved in this stage III

Stage 4: Methane fermentation (CH 4 )

CH3SCH2CH2CH(NH2)COOH + 2H  CH3SH + CH3CH2CH2(NH2)COOH

The active microorganisms in this stage are anaerobic ones, called methane bacteria In this stage, the formation of methane and acid occurs simultaneously, although acid formation is significantly reduced As acid and hydrogen are converted to CH4 and CO2, the pH of the leachate in the landfill will increase to reach the average value from 6.8 to

8 BOD5 and COD values, heavy metal concentrations and leachate conductivity will be reduced

Stage 5: Stability

The stage of stability occurs after the biodegradable organic materialsare converted to

CH4 and CO2 in the stage 4 As moisture continues to penetrate into the newly added waste stream, the transformation process continues The speed of generating gas will be reduced significantly during this stage as most of the available nutrients have been washed away with leachate in earlier stages and the remaining substances are mostly slowly biodegradable ones The gas produced mainly in this stage is CH4 and CO2 On the surface of the landfill pit, a group of aerobic bacteria will begin to appear and oxidize methane into CO2 During thisstage of stability, the leachate often contains humic acid and fulvic acid which are difficult for biological processes to continue to take place

The duration of each stage of the process of froming gases varies depending on the composition of the organic matter, nutrient composition, and moisture content of the solid waste, the humidity of the landfill site If not sufficiently humid, the burial velocity of the landfill site will be reduced Compaction (reduction of voids) and good cover will reduce the possibility of wetting the waste in the burial site and leading to a reduction in the rate of biochemical transformation biology and vitality

Biogas is generated by the decomposition of organic matter through the five stages described above In the first stage, the gas generates mainly carbon dioxide and some other gases such as N2, O2 and NH3 The presence of CO2 in the garbage dumps facilitates the anaerobic microbial growth and hence initiates the formation of methane (CH4) and produces odor gas such as H2S, CH3SH

1.4.3 Source causing foul odor from landfill sites

According to scientific literature, anaerobic biodegradation of solid waste at landfill sites generates about 168 odorous compounds such as organic acids, aldehydes, aldehydes, gas mixtures, esters, sulphites, mercaptans.… and most of them have characteristic odors The main odor groups are as follows:

- Group of volatile fatty acids

- Group of indols and phenol compounds

- Amino group and volatile amines

- Group of compounds containing volatile sulphides such as sulphite, mercaptans The odor of landfill sites is derived from the following main sources:

Dumping fresh garbage: Due to the influence of aerobic microorganisms, some biodegradable organic compounds and amine compounds in the garbages, especially food components, will be degraded to produce compounds causing main odor such as NH3, fatty acids Besides the odor from fresh garbages, the smell is also derived from leachate

Decomposition of solid waste: Due to the major impact of anaerobic microorganisms, the biodegradation process will take place in a long time and the amount of gas generated is very large The compounds causingthe odorduring this decomposition have many different components and are concentrated mainly in the 4 odor groups mentioned above The process of producing odor at this stage is highly dependent on landfill and overlay measures

Leachate: The compounds causing odorproduced during the leachate degradation process depend on the surface of the leachate reservoirs, the treatment measures, the weather conditions of each season, etc

In addition, social impacts can also be seen through the reduction of land values in areas affected by bad odors

1.5 Method of assessment and odor meter

1.5.1 The nature of the odor

An odor can be described as either pleasant or unpleasant, and odors from a landfill fall under the unpleasant category The actual smell of an odor gives very little information

on the compounds in that odor, since there are various compounds that can be mixed together that cause the odor from any landfill as was seen in table : Sulfides and ammonia are the most common odor causing source in a landfill, but sulfides can cause the strongest of smells since humans can detech them at very low concentrations Odors are highly unlikely to cause any major health effects, but have been known to cause eye irritation and headaches at high concentrations It depends on the individual, since every person reacts differently to certain odors The effects of some major gases are as follows

Harms of sulfur compounds (H 2 S)

H2S is a turbid gas, easy to spread in the air with a characteristic rotten egg odor H2S is rapidly oxidized to form sulphates and compounds with lower toxicity When exposed

to H2S ill cause the phenomenon of hypoxia, and can lead to death This is the typical syndrome of sulfur poisoning in workers working in the sewers In addition, frequent exposure to H2S also results in chronic poisoning Symptoms such as depression, sleep disturbances, headaches, dizziness, difficulty focusing, increased sweating, autoimmune disorders, bronchitis

Table 1.7 The effect of hydro sulfua gas on humans [12]