Environment Group Assignment

7/31/2019 Environment Group Assignment

1/22

1

Group Assignment 1 : Landfill Leachate Treatment

CHEMICAL ENGINEERING PROGRAMME

SEMESTER I (2011/2012)

KC 41503 ADVANCE ENVIRONMENTAL ENGINEERING

Group Members MATRIX NUM

ADELINE JELUNG BK08110232

BENJAMIN KAM BK08110127

CHEOH LIEW CHUAN BK08110093

DAVID SIAW WEN CHIIN BK08110031

EWAN TAMBAKAU @ WILLIAM BK08110189

FIRDAUS AZMEE BK08110175

LIOW KAI SING BK08110077

LOWEL CHONG BK08110131

SUSYANA SAMIRAN BK08110338


2/22

2

Table of Contents

1.0 Introduction ........................................................................................................ 3

1.1 Leachate ......................................................................................................... 3

1.2 Leachate Quality .............................................................................................. 3

1.3 Impact of Leachate .......................................................................................... 3

1.4 Leachate Treatment ......................................................................................... 4

2.0 Landfill Selection ................................................................................................. 5

3.0 Leachate Type and Data ...................................................................................... 7

3.1 Kayu Madang Landfill Leachate Data ................................................................. 7

3.1.1 Analysis .................................................................................................... 7

3.2 Environmental Quality (Sewage) Regulations 2009 ............................................ 11

3.3 Available Water Treatment Technology ............................................................. 12

4.0 Process Selection ............................................................................................... 13

4.1 Process Description ......................................................................................... 13

5.0 Conceptual Design and Calculation ...................................................................... 14

6.0 Discussion ......................................................................................................... 17

7.0 References ........................................................................................................ 18

Appendix A Questions Asked During Presentation ......................................................... 20

Appendix B Discharge Limit Set by Department of Environment ..................................... 22


3/22

3

1.0 Introduction

1.1 Leachate

Leachate is any liquid that, in passing through matter, extracts solutes, suspended solids or

any other component of the material through which it has passed. The precipitation that

falls into a landfill, coupled with any disposed liquid waste, results in the extraction of the

water-soluble compounds and particulate matter of the waste, and the subsequent

formation of leachate. Leachate produced from municipal solid waste landfill sites is

generally heavily contaminated and consist of complex wastewater that is very difficult to

deal with. Leachate produced form these waste dumping sites is heterogeneous and exhibits

huge temporal and seasonal variations.

1.2 Leachate Quality

The composition of leachate varies widely depend on waste type and the waste age

(Christensen et al., 1994). Leachate is characterized by high concentration of organic matter

(biodegradable and non-biodegradable), ammonia nitrogen, heavy metals, and chlorinated

organic and inorganic salts. Typically, the leachate can be characterized into three major

groups. The three major groups are mainly organic matters, inorganic matters and

xenobiotic organic compounds. Leachate pollution index (LPI) provides an overall pollution

potential of a landfill site.

Table 1.1 Pollutants in leachate (Aik H. L. et al., 2010)

Group of Pollutants In Leachate Components

Organic Matters Acids, alcohols, aldehydes and others such as Chemical

Oxygen Demand (COD), Biochemical Oxygen Demand

(BOD), Dissolved Organic Carbon (DOC), Volatile fatty

acis and refractory compound include fulvic-like and

humic like compounds

Inorganic Matters Sulfate, chloride, ammonium, calcium, magnesium,sodium, potassium, hydrogen carbonate, iron and

manganese and heavy metal like lead, nickel, copper,

cadmium, chromium and zinc

Xenobiotic organic compounds Aromatic hydrocarbon, phenols, chlorinated aliphatics,

pesticides and plasticizers include PCB, Dioxin, PAH, etc.

1.3 Impact of Leachate

A poorly designed landfill with no leachate collection system would face the consequences of

groundwater pollution. A release of leachate to the groundwater may present several risks

to human health and the environment. The release of hazardous and non-hazardous


4/22

4

components of leachate may render an aquifer unusable for drinking-water purposes and

other uses. Leachate impacts to groundwater may also present a danger to the environment

and to aquatic species if the leachate-contaminated groundwater plume discharges to

wetlands or streams.

Once leachate is formed and is released to the groundwater environment, it will migrate

downward through the unsaturated zone until it eventually reaches the saturated zone.

Leachate then will follow the hydraulic gradient of the groundwater system and eventually

pollute the groundwater. It is therefore important to collect and treat the leachate formed in

the landfill.

1.4 Leachate Treatment

A number of ways may be applied to treat the leachate, these usually resulting in changes

of chemistry and a general reduction of strength from the original release. These treatment

are either physical (filtration, sorption, advection, and dispersion), chemical (oxidation-

reduction, precipitation-dissolution, adsorption, hydrolysis, and ion exchange), and biological

(microbial degradation).


5/22

5

2.0 Landfill Selection

Overall there are more than 200 landfills in Malaysia serving the need of the city to remove

solid waste. Our group has chosen the landfill in Kayu Madang which is located in Kota

Kinabalu.

Location (GPS 6 o 06' 25.9" N; 116o 10' 29.1" E)

The site is located at Kg. Lapasan, Telipok within the Kota Kinabalu Industrial Park, 18 km

northeast of Kota Kinabalu City, see Figure 5.9. The waste disposal site covers an area of

8.9 hectares (22 acres).

History

Disposal of waste at this site started in 1997 and is expected to last until 2015. It has a

capacity of 15,333 cubic metres. The following picture shows the layout of the landfill.

Figure 1.1 Layout plan of Kayu Madang Landfill (Christianus, 2005)


6/22

6

Waste collection coverage and amount of waste received

This site receives all types of waste except scheduled and hazardous waste from the rating

areas of Kota Kinabalu City, Penampang, Tuaran and Kota Belud. It receives an estimated

total of 9,000 tonnes of waste per month.

Site characteristics

The site is located in a gently sloping northeast-southwest trending valley with sloping hills

at the northeast and southwest. The valley floor is underlain by alluvium while sandstone

and shale underlie the hills. The surface runoff at the north western part of the valley flows

northwest into the Salut Bay. The immediate surrounding has not been developed and is

covered with secondary forest.

Design

Kayu Madang landfill is a Level IV sanitary landfill. It has a bottom liner but it is only in the

middle part; the liner comprises clay (1 m), sand (2 inches) and aggregate (5 inches). The

area is fenced with a gate and guard. Leachate is collected and pumped to the oxidation

pond. Groundwater wells have been installed. There is also weigh bridge and wheel wash.

Figure 1.2 Schematic diagram of Kayu Madang Landfill (Christianus, 2005)

Existing Leachate Treatment

It is to be noted that there is existing treatment for the leachate produced in the landfill.

The existing treatment plant, however, is inefficient in treating the leachate. The raw

leachate is pumped into a facultative pond before channeled into two maturation ponds.


7/22

7

3.0 Leachate Type and Data

The selection of water treatment technology should be based on the type of influent

received by the water treatment facility. A water treatment facility for a palm oil mill might

be different from the water treatment facility for paper mill; this is true for landfill leachate

as well. By knowing the content of the effluent that needs to be treated, we can select

appropriate method that would best treat the effluent.

In this paper, we will evaluate the composition of leachate produced by Kayu

Madang landfill and select a suitable water treatment technology in comply with the

standard set by the Malaysian Government which can be referred in the Environmental

Quality (Sewage) Regulations 2009.

3.1 Kayu Madang Landfill Leachate Data

The selection of process presented in this paper will rely mostly on the data gathered from

journals and internet. Below is the leachate composition for the landfill site in Kayu Madang.

Table 3.1 physico-chemical of leachate in Kayu Madang (Christianus, 2005)

Parameter Range Average

BOD 22 208 mg/L 80 mg/L

COD 46 829 mg/L 313.4 mg/L

Suspended Solid 18 346 mg/L 121 mg/L

pH 6.61 7.61 7.184

Ammoniacal N 10.28 277 mg/L 168.256 mg/L

Nitrogen 35.18 296 mg/L 210.23 mg/L

Phosphate 0.5 mg/L 0.5 mg/L

Cadmium 0.01 mg/L 0.01 mg/L

Plumbum (Lead) 0.06 mg/L 0.06 mg/L

Chromium 0.05 mg/L 0.05 mg/L

Copper 0.03 mg/L 0.03 mg/LManganese 0.05 1.3 mg/L 0.49 mg/L

Nickel 0.04 mg/L 0.04 mg/L

Zinc 0.05 0.06 mg/L 0.055 mg/L

Iron 2.4 7.7 mg/L 4.67 mg/L

3.1.1 Analysis

The data in the table was acquired from the year 1997 to year 1999, with the landfill built

and began operation in 20 September 1997 (Christianus, 2005). The landfill is now 14 years

old, we expect some variation in the content of leachate as it age. Regrettably, the most


8/22

8

recent data regarding the physico-chemical of the leachate is not available. In order to

select an appropriate water treatment process, we need to know the composition of the

leachate for the landfill. In this paper, we will attempt to compare the composition of Kayu

Madang Landfill Leachate with other data from other researches that are based in Malaysia

and other tropical countries.

As stated by Tchobanoglous et al. (1993) in his research, the composition of the

leachate will change as the landfill age. According to the data he collected, the magnitude of

pollutant in the leachate will depreciate overtime; this finding is in accordance with the

research done by Robinson & Luo (1991).

The selection of data will focus on the old landfill especially those in Malaysia and our

neighbouring countries and other tropical countries. The table below shows the place of

landfill, location, its corresponding age and the source of the data:

Table 3.2 Various Landfill in Malaysia and other tropical countries

Landfill Location Country Year Operated Reference

Pulau Burung Penang Malaysia 1991 Aziz H.A et al. (2003)

Kulim Penang Malaysia 1996 Aziz S.Q. et al. (2010)Nonthaburi Bangkok Thailand 1982 Theepharaksapan S. (2010)

Table 3.3 Comparison of values of leachate composition

Parameter Unit Pulau Burung Kulim Nonthaburi Kayu Madang

BOD mg/L 48 -105 135 476 400 22 208

COD mg/L 1533 2580 630 2860 2700 46 829

Suspended Solid mg/L 159 233 232 1374 290 18 346

pH - 7.5 9.4 6.93 8.26 8.44 6.61 7.61

Ammoniaca-N mg/L 360 730 130 1309 112 10.28 277

Nitrate-N mg/L 900 3200 400 2600 - 35.18 296

Phosphate mg/L 10 43 8.0 40 - 0.5

Cadmium mg/L - - 0.05 0.01

Plumbum (Lead) mg/L - - - 0.06

Chromium mg/L - - 0.17 0.05

Copper mg/L 4.60 - 0.50 0.03

Manganese mg/L 15.5 - - 0.05 1.3

Nickel mg/L - - 0.32 0.04

Zinc mg/L 0.10 0 1 - 0.05 0.06Iron mg/L 4.1 -19.5 0.6 11.4 2.95 2.4 7.7


9/22

9

Both Tchobanoglous et al. (1993) and Kostova (2006) did a research and published their

findings regarding the variation of leachate composition over time. The findings can be

found in the table below:

Table 3.4 Concentration of some leachate characteristic at different phases (Kostova, 2006)

Leachate Transition

phase

Acid-formation

phase

Methane fermentation

phase

Final maturation

phase

Constituents (0 5 years) (5 10 years) (10 20 years) (> 20 years)

BOD 100 11000 1000 57000 100 3500 4 120

COD 500 22000 1500 71000 150 10000 30 900

TOC 100 3000 500 28000 50 2200 70 260

Ammonia 0 190 30 3000 6 430 6 430

NO2-N 0.1 500 0.1 20 0.1 1.5 0.5 0.6TDS 2500 - 14000 4000 - 55000 1100 - 6400 1460 4640

Table 3.5 leachate characteristic for new and mature landfills (Tchobanoglous et al., 1993)

Value, mg/L

New landfill (less than 2 years) Mature landfill

(greater than 10

years)Constituent Range Typical

BOD 2000 30000 10000 100 200

TOC 1500 20000 6000 80 160

COD 3000 60000 18000 100 500

Suspended Solid 200 2000 500 100 400

Organic Nitrogen 10 800 200 80 120

Ammonia nitrogen 10 800 200 20 40

Nitrate 5 40 25 5 10

Total Phosphorus 5 100 30 5 10

Ortho Phosphorus 4 80 20 4 8

Alkalinity (CaCO3) 1000 10000 3000 200 1000

pH (no units) 4.5 7.5 6 6.6 7.5

Calcium 200 3000 1000 100 400Magnesium 50 1500 250 50 200

Potassium 200 1000 300 20 400

Sodium 200 2500 500 100 200

Chloride 200 3000 500 100 400

Sulphate 50 1000 300 20 50

Total Iron 50 1200 60 20 200


10/22

10

By looking at the tabulated data by both Tchobanoglous et al. (1993) and Kostova (2006),

we can make the following assumption:

1. BOD, TOC, COD, Suspended Solid reduce dramatically when the landfill is over 10years old.

2. The leachate becomes more alkaline over the time but not more than 7.5.3. Ammonia and nitrate content varies from time to time but is not significantly larger

than the first few years.

4. The metal content of leachate reduced by more than 50% after 10 years comparedto the first year.

Observing from the table, we noticed that there is a hike in concentration of composition of

leachate between year 5 and year 10. The concentration of the composition of leachate

declines steadily upon after 10 years. Since the leachate of Kayu Madang is more than 10

years. We have come up with the following values for the expected current leachate

composition by drawing values from other available leachate composition (Table 2.2) that is

within the scope of values is table 2.3 and table 2.4.

Table 3.6 Estimated physico-chemical of leachate in Kayu Madang in year 2011

Parameter Average

BOD 400 mg/L

COD 630 mg/L

Suspended Solid 159 mg/L

pH 8.3

Ammoniacal N 112 mg/L

Nitrogen 400 mg/L

Phosphate 10 mg/L

Cadmium 0.01 mg/L

Plumbum (Lead) 0.03 mg/L

Chromium 0.025 mg/LCopper 0.015 mg/L

Manganese 0.25 mg/L

Nickel 0.02 mg/L

Zinc 0.025 mg/L

Iron 2.30 mg/L

The data in the table above will be used in the analysis of the type of water treatment

process used in this paper.


11/22

11

3.2 Environmental Quality (Sewage) Regulations 2009

In December 2009, the Department of Environment (D.O.E) Malaysia has revised the

Environmental Quality (Sewage) Regulation 2009. All the sewage discharge from the

domestic sewage treatment plant is typically subjected to the local, state and federal

regulations and standards. Under the regulation, the acceptable conditions for discharge of

leachate have been amended and can be referred in the appendix B.

The new standard of discharge limit with comparison to the projected composition of

leachate for the need for the treatment is summarized in the table below:

Table 3.7 Projected effluent and discharge limit with required action

Parameter Discharge Limit Projected Effluent Action required

BOD 20 mg/L 400 mg/L Yes

COD 400 mg/L 630 mg/L Yes

Suspended Solid 50 mg/L 159 mg/L Yes

pH 6.0 9.0 8.3 No

Ammoniacal N 5 mg/L 112 mg/L Yes

Nitrate N - 400 mg/L NoPhosphate -

10 mg/L No

Cadmium 0.01 mg/L 0.01 mg/L No

Lead (Pb) 0.10 mg/L 0.03 mg/L No

Chromium 0.20 mg/L 0.025 mg/L No

Copper 0.20 mg/L 0.015 mg/L No

Manganese 0.20 mg/L 0.15 mg/L No

Nickel 0.20 mg/L 0.02 mg/L No

Zinc 2.0 mg/L 0.025 mg/L No

Iron (Fe) 5.0 mg/L 2.30 mg/L No

In accordance with the law gazetted by the government, we come to a conclusion that only

BOD, COD, Suspended Solid and Ammoniacal Nitrogen need to be treated before it is being

discharged into the streams.


12/22

12

3.3 Available Water Treatment Technology

Many leachate treatment methods have been proposed and can be found in the journal. The

table below is the summary of the processes and technology its effectiveness in treating

leachate.

Table 3.8 Comparison based on efficiency, installation and operation cost (Renou S. et

al., 2008; Madu J.I., 2008)

ProcessAverage Removal (%) Installation

& operationSkilled

personnelBOD COD TKN SS

Transfer

Recycling >90 60 80 - - Less No

Lagooning 80 40 95 >80 30 40 Less No

Physico/ChemicalCoagulation/flocculation - 40 - 60 80 Less No

Chemical precipitation - 80 60 90 >80 60 80 Less NoAnaerobic Processes >80 60 80 >80 60 80 Less NoPre-Anoxic Detrification >90 >90 >80 >75 Less NoMembrane Bioreactor >80 >85 >80 >99 Expensive No

Membrane FiltrationUltrafiltration - 50 60 80 >99 Expensive YesNanofiltration 80 60 80 60 80 >99 Expensive YesReverse Osmosis >90 >90 >90 >99 Expensive Yes

*Installation & operation cost and the need for skilled labour varies for Aerobic Process and

Anaerobic Processes. Biological aerated filter, Anaerobic filter are examples of processes

needing expensive installation & operation cost as well as skilled labour.


13/22

13

4.0 Process Selection

A conventional activated sludge system will not be able to meet the new standard imposed

by the government as proven by Kutty S.R.M. et al. (2011). Thus, a more detailed process

with emphasis on the removal of nitrogen needs to be selected. In this case, our group has

chosen the Pre-Anoxic Detrification with activated sludge Process.

4.1 Process Description

The process of Pre-Anoxic Detrification with activated sludge can be best explained from the

diagram below:

Figure 4.1 Process flow of Pre-Anoxic Detrification with activated sludge (Gunasekara,

2011)

The Pre-Anoxic Detrification with activated sludge consists of an anoxic tank followed

by the aeration tank where nitrification occurs. Dissolved nitrogen in the form of ammonium

will be converted into nitrite ions and then to nitrate ions in the presence of oxygen by

nitrifying microorganism.

Nitrate produced in the aeration tank is recycled back to the anoxic tank where

denitrification will occur with the end product as Nitrogen. This overall process will not only

treat BOD, COD, Suspended Solid but also the ammoniacal-Nitrogen contained in the

leachate.


14/22

14

5.0 Conceptual Design and Calculation

The core principle of the design was to have a complete mix activated sludge process

together with anoxic tank.

The leachate pumped up from the flow to the facultative pond first, then to the maturation

pond. After final maturation pond treatment, effluent discharge to the sea through Salut

river. The new system proposed (see Figure 5.1) is to further reduce BOD, COD to meet the

Environmental Quality (Sewage) Regulation 2009.

Figure 5.1: Proposed further treatment system

Existing plant effluent characteristic:

BOD5 = 400mg/L

Let,

Flow, Q= 0.150M3/s

Use Value of growth constants (source: Metcalf & Eddy, 2003 and Shahriari et al., 2006)

Ks = 100mg/L BOD5; m=2.5d-1; kd=0.050; Y=0.50mg VSS/mg BOD5 removed.

Assuming that the secondary clarifier can produce an effluent with only 30.0mg/L SS. We

can extimate the allowable soluble BOD5 in the effluent using the 63-percent assumption.

S = BOD5 allowed BOD5 in suspended solids

S = 30.0 (0.630)(30.0) = 7.4mg/L


15/22


16/22

16

The volume of the aeration tank is then estimated using equation below:

The volume of the anoxic tank is estimated by setting the hydraulic retention time of the

tank roughly 25% of aeration tank as done by a group research team from Universiti

Teknologi PETRONAS in their pilot plant (Kutty S.R.M. et al, 2011)

) )


17/22

17

6.0 Discussion

Many of the values in the table especially the current Kayu Madang landfill leachate might

not be accurate. The values are projected by referring from the other samples from other

landfills and the finding of journals. In order to get a better and more accurate data to

design a suitable waste water treatment facility, a most recent sample collection and

analysis is required.

There might be some slight variation in the calculation made as some of the

parameter constant (growth constant for microbes) are taken from journals and researches

from western countries. Very little research on the microbes activities in the tropical country

are observed and hence the limitation on the data during calculation.

While the landfill does not accept scheduled and hazardous waste which could

potentially lower the amount of metal in the leachate, the varying amount of BOD, COD and

TSS should be taken note of. Sabah has a very unique feature of unpredictable rainfall

which could potentially increase the amount of effluent, this could overload the water

treatment system. The equalizer installed at the head of the treatment plant should act as a

medium for concentration and flow equalizer.

The anoxic tank and anaerobic aeration tank could be combined for space efficiency,

such combination commonly dubbed as aeration/anoxic reactor. In this type of system, an

overall oxygen deficit condition is hard to be established across the entire contents of the

reactor and, unlike what is found with the reactors-in-series mode, there is no oxygen

uptake rate gradient to establish an initial oxygen deficit environment. Hence, this system is

generally not preferable.

Due to the stringent enforcement of the effluent limit set by the government, a

special treatment needed to be carried out. The Pre-Anoxic Detrification with activated

sludge process is one of the process modifications where non-conventional method is

applied. To maximize the denitrification performance in anoxic tank, oxygen delivery in the

anoxic tank should be 50% to 70% of the demand.


18/22

18

7.0 References

Aik H. L., Hamid N. & Yung T. H. 2010. Influence of Waste Age on Landfill Leachate Quality.International Journal of Environmental Science and Development. 1(4): 258-264.

Aziz H.A., Yusoff M.S., Adlan M.N., Adnan N.H., and Alias S. 2003. Physico-Chemical

Removal of Iron From Semi0aerobic Landfill Leachate by Limestone Filter. WasteManagement. 24: 353-358.

Aziz S.Q., Aziz H.A., Yusoff M.S., Bashir M.J.K., and Umar M. 2010. LeachateCharacterization in Semi-aerobic and Anaerobic Sanitary Landfills: A Comparative Study.Journal of Environmental Management. 91: 2608-2614.

Barlaz, M., Baun, A., Christensen, T., Kjeldsen, P., Ledin, A. and, Rooker A.. 2002.Presentand Long-Term Composition of MSW Landfill Leachate : A Review. Critical Reviews inEnvironmental Science and Technology. 32(4): 364-371.

Chang, K.C., Chain. E.S.K., Dertien, J.T., Harper, S.R. & Pohland, F.G. 1985. Leachate

generation and control at landfill disposal sites. Water Pollution Resources Journal Canada.20(3): 10-24.

Christensen T.H., Kjeldsen P., Albrechtsen H.J., Heron G., Nielson P.H., Bjerg P.L., and HolmP.E. 1994. Attenuation of Landfill Leachate Pollutants in Aquifers. Critical Reviews inEnvironment Science and Technology. 24: 119-202.

Christianus P. 2005. Leachate Management in Kayu Madang Landfill, Telipok. Thesis.Universiti Teknologi Malaysia.

Gunasekara S.N. 2011. Improvements on Municipal Wastewater Treatment by: ChemicalPre-Precipitation with Ca2+ & Mg2+ and Acid Hydrolysis of Toilet Paper. Master Thesis. Royal

Insitute of Technology.

Ifeanyichukwu M.J. 2008. New Leachate Treatment Methods. Master Thesis. Lund University.

Kostova I. 2006. Leachate from Sanitary Landfills-Origin, Characteristics, Treatment.Borovetz: University of Architecture, Civil Engineering and Geodesy.

Kutty S.R.M., Isa M.H., Leong L.C. 2011. Removal of Ammonia-Nitrogen (NH3-N) and Nitrate(NO3

-) by Modified Conventional Activated-Sludge System to Meet New D.O.E Regulations.Perak: Universiti Teknologi PETRONAS.

Laugesen C.H., Lim P.S. & Mohd Iskandar M.A. Solid waste disposal in Sabah. Environmental

Conservation Department, Sabah Survey Report August 2002.

Regulations 2009. Environmental Quality (Control of Pollution From Solid Waste TransferStation and Landfill) Regulations 2009 (Regulation 13). Kuala Lumpur: International LawBook Service.

Renou S., Givaudan J.G., Poulain S., Dirassouyan F., Moulin P. 2007. Landfill LeachateTreatment: Review and Opportunity. Journal of Hazardous Materials. 150: 468-493.

Robinson H. and Luo M. 1991. Characterisation and Treatment of Leachates From HongKong Landfill Site. Journal of the Institution of Water and Environmental Management. 5(6):326-335.


19/22

19

Shahriari H., Eskicioglu C. and Droste R. L. 2006. Simulating Activated Sludge Systems bySimple-to-Advanced Models. Journal of Environmental Engineering. ASCE 132(1): 42-50.

Tchobanoglous G., Theisen H., and Vigil S. 1993. Integrated Solid Waste ManagementEngineering Principles and Management Issues. Singapore: McGraw-Hill, Inc.

Theepharaksapan S., Chiemchaisri C., Chiemchaisri W., and Yamamoto K. 2011. Removal ofPollutants and Reduction of Bio-toxicity in a Full Scale Chemical Coagulation and ReverseOsmosis Leachate Treatment System. Bioresource Technology. 102: 5381-5388.


20/22

20

Appendix A Questions and Answer During Presentation

1. What is the capacity of the landfill?A: The Kayu Madang landfill have a capacity of 15,333 cubic metres.

2. Please cite the reference for the schematic diagram of landfill.A: Christianus P. 2005. Leachate Management in Kayu Madang Landfill, Telipok. Thesis.

Universiti Teknologi Malaysia.

3. Why you did not choose tropical work and data (calculation part)?A: Very little research on the microbes activities in the tropical country are observed and

hence the limitation on the data during calculation.

4. For the process proposed in UTP thesis (Kutty S.R.M. et al.), criticize the method.Nothing is perfect.

A: They uses a pilot plant where the leachate is made up of lab chemicals and not real

leachate, hence the possibility of inaccuracy. In the process, steady state flow were used for

the pilot plant, real life situation may differ from the pilot plant. The calculation for tank size

were BOD based and not Ammoniacal-Nitrogen. It is optimized for BOD and not

Ammoniacal-Nitrogen.

5. How do you achieve constant flow?A: By using equalizer tank, we can achieve constant flow

6. How do you measure the flow rate of leachate?A: Any flow measuring device such as rotameter can be used to measure the flow.

7. Where the waste comes from?A: This site receives all types of waste except scheduled and hazardous waste from the

rating areas of Kota Kinabalu City, Penampang, Tuaran and Kota Belud.

8. How do you maximize the performance of denitrification? What is the parameterinvolved?

A: Nitrification largely depended on the food/mass ratio and the deficiency of oxygen in the

liquid. The retention time also affect the performance. By increase the food/mass ratio,

adjusting the oxygen of 50-70% of the demand and lengthen the rentention time.


21/22

21

9. Why use anoxic tank instead of other tank? Think of a simultaneous treatment withanoxic and anaerobic.

A: Anoxic tank is used for its denitrification process which is good in eliminating the

ammoniacal-nitrate. The anoxic tank and anaerobic aeration tank could be combined for

space efficiency, such combination commonly dubbed as aeration/anoxic reactor. In this

type of system, an overall oxygen deficit condition is hard to be established across the entire

contents of the reactor and, unlike what is found with the reactors-in-series mode, there is

no oxygen uptake rate gradient to establish an initial oxygen deficit environment. Hence,

this system is generally not preferable.

10.How much sludge come out? How do you measure?A: The amount of sludge coming out has yet to be ascertain as not enough data is available

for calculation at the moment. Sludge can be treated as viscous liquid and can be measure

same as liquid.

11.If during heavy rainfall, how do you prevent it from overflow?A: Equalizer would be able to contain the rainfall and adjust the flowrate to prevent overflow

of the tank.

12.How to maximize performance of nitrification, is the aeration control important, how doyou control it?

A: Similar to question number 8.


22/22

22

Appendix B Discharge Limit Set by Department of Environment

Environment Group Assignment

Documents