Tadeusz MARCINKOWSKI; Wojciech SŁOMKA

Wroclaw University off Technology

Institute of Environment Protection Engineering

 

ANALYSIS OF EFFECTS OF INDUSTRIAL WASTE LANDFILL

ON SUBSURFACE WATER

 

INTRODUCTION

Vehicles scrap, metal scrap, as well as used home and industrial electric and electronic equipment, are waste that contain hazardous components, such as heavy metals, oil products, etc.[1].

In case of inappropriate or erroneous dealing with such waste, they may endanger human life and health or the environment. Recovery and recycling of raw materials from waste is on the one hand a challenge for our civilization, and on the other hand a legal requirement [2,3,4].

During recovery of raw materials from these groups of waste a significant mass of byproducts is created (waste from waste processing), the quantity of which – in case of the neutralization plant analyzed here – may reach as much as 30% of initial mass subjected to processing. This quantity includes a considerable portion that is not suitable for management and can only be disposed on a landfill.

Neutralization plant is located in south-west region of Poland and has the own industrial waste landfill that is being monitored since its launching in the year 2001. Monitoring refers to the quality of piezometric water in the vicinity of the plant.

The obligation of monitoring of landfills results, among other things, from the legislation of the European Union that – with the aim of environmental protection as a whole, and protection of human health in particular – requires avoiding high concentrations of hazardous pollutants in subsurface water, reducing them or preventing their formation [5].

Our research was directed to aspects of safe depositing industrial waste as well as the quality of subsurface water in the vicinity of the landfill.

 

ACTIVITY OF THE SCRAP MATERIAL PROCESSING PLANT

The scrap processing plant presented here is one of the biggest in the country. Apart from purchasing metal scrap, the plant deals with conversion of used household equipment and auto hulks and other large-size waste, and for two years also of used electric and electronic equipment.

Productive activity of the plant is based on the processing line presented schematically on Figure 1. The main element of the line are high-duty rippers crushing scrap and a technological process, in which crushed waste is subjected to sorting and segregation into particular morphological fractions. Some fractions are marked out to reutilization (ferrous and non-ferrous metals and separated so-called alternative fuel). The remainder, in shape of the finest fraction, sorted on a sieve of 15 mm mesh, as well as other unmarketable waste, are transferred to deposition on own landfill located in the southern area of the plant (Figure 2).

 

Figure 1. Processing line for scrap disintegrating.

Description:

1 – ripper-crusher,                                      7 – non-ferrous metals separator,

2 – hopper container,                                8 – band conveyor,

3 – band conveyor,                                    9 – two-stage rotary sieve,

4 – rotary sieve,                                        10 – container for flammable waste,

5 – band conveyor,                                  11 – band conveyor,

6 – ferrous metals separator                   12 – container for waste designed to reutilization.

 

Figure 2. The landfill of industrial waste.

In order to determine the environmental effect of deposited waste, a preliminary analyses of the physicochemical composition of raw waste as well as of water extract of this waste were performed [6]. Results of this research are summarized in Tables 1 and 2.

 

Table 1.  Physicochemical composition of the fine fraction of waste [6].

No.

Parameter

Unit

Trial 1

Trial 2

1

pH

 

7,5

7,5

2

Moisture content

%

13,93

9,03

3

Organic mass

%

11,43

16,47

4

Ammonia nitrogen

mg NNH4/kg d.m.

90,74

74,92

5

Organic nitrogen

mg Norg/kg d.m.

61,13

2140,64

6

Overall nitrogen

mg Nog/kg d.m.

151,87

2215,56

7

Acid-insoluble substances (SiO2)

% d.m.

28,17

24,64

8

Calcium

mg Ca/kg d.m.

21085,92

20644,91

9

Chromium

mg Cr/kg d.m.

484,625

436,099

10

Zinc

mg Zn/kg d.m.

27499,56

27546,20

11

Cadmium

mg Cd/kg d.m.

121,244

132,127

12

Nickel

mg Ni/kg d.m.

510,455

170,075

13

Iron

mg Fe/kg d.m.

273502,0

303775,1

 

The analysis of physicochemical composition of fine fraction of waste from tests 1 and 2  showed high content of zinc, iron and calcium.

Elution tests of these metals, both for trial 1 and trial 2 (Table 2), demonstrated low solubility  in water, that is a result of their metallic form..

Water extracts of waste deposited on the landfill were made four times later, in different periods (Table 2). They showed slightly increased pH, quite low value of specific electrolytic conductivity, as well as low content of nitrogen compounds. Despite of high content of metallic forms of metals (that occur in that form in solid samples due to their origin), they do not produce a significant environmental hazard. Table 2 also shows a beneficial effect of alkalization (with hydrated lime in a dose of 2.5%) on intensivity of elution of metal compounds from waste.  


 

 

Table 2. Physicochemical composition of water extracts from waste – fine fraction after separation of disintegrated scrap.

 

 

 

No.

Parameter

Unit

 

 

Trial 1

[6]

 

 

Trial 2

[6]

Sample of raw waste

Sample with addition of hydrated lime (dose of 2.5%)

Mineral fraction separated on

blooming shear

Mineral fraction separated on

sorting line

 

1

pH

 

7,84

7,64

7,69

10,55

8,22

7,94

2

Specific electrolytic conductivity

mS/cm

0,704

0,884

0,546

0,568

0,802

0,699

3

COD Cr

gO2/m3

99,84

203,52

4

Ammonia introgen

gNNH4/m3

1,3

2,4

0,3

0,4

2,5

1,75

5

Zinc

g Zn/m3

2,60

3,44

3,60

0,35

0,286

0,236

6

Cadmium

g Cd/m3

0,006

0,010

0,02

0,007

<0,003

<0,0030

7

Chromium

g Cr/m3

0,03

0,02

0,02

0,023

0,040

0,032

8

Nickel

g Ni/m3

0,027

0,016

0,28

0,19

0,156

0,140

 


 

DESCRIPTION OF CONTROL RESEARCH

The examination of environmental effects of deposited waste was performed on the ground of cyclic observation of changes in subsurface water quality in the vicinity of the landfill.

In order to do that, four piezometric drawholes were made to the depth of the first water table (about 5-6 m under the ground surface level). The direction of groundwater flow was determined as being from north-east towards south-west. On account of dense industrial building on the northern side, piezometers were localized in the immediate vicinity of the landfill (Figure 2).

Piezometers P1 i P2 were designed to observation of the quality of water flowing into the landfill. Comparing the quality of water in piezometers P3 and P4 to the quality in piezometers P1 and P2, effects of deposited waste on water environment were analyzed. In addition, changes in composition of eluates were observed. Samples of eluate were taken from the pond located in western part of the landfill (Figure 2). Eluates flow down to the pond through the system of drain pipes [8].

For analysis of changes in subsurface water an overall observation of the landfill parameters, as well as of the manner of waste and eluates management were helpful.

Piezometric water was collected with small pumping set equipped with two submerged rotodynamic pumps having efficiency of 5 dm3/min and elevation head of 10 m. Before taking samples, purifying pumping of piezometric drawholes was performed, drawing out about triple volume of stagnating water from each drawhole.

The ground of decision about sampling was a stability of specific electrolytic conductivity and pH, measured during clarification of drawholes.

The following parameters were determined in samples of water: pH, specific electrolytic conductivity, nitrogen compounds, CODCr and metals (Zn, Cr, Ni, Hg).  

Determination of parameters was performed according to the reference methodologies [7].

Results of water research was presented as plots of changes in values of contamination indices during several years’ research cycle, i.e. from September 2003 till September 2007 (Figures 3 and 4).


Figure 3. Changes in subsurface water quality during control observations – general indices.

 

Figure 5. Changes in subsurface water quality during control observations – metals.

InterpretATION OF CHANGES IN COMPOSITION OF SUBSURFACE WATERS

Expected and logical progress of plots of analyzed contaminants concentrations is presented for specific electrolytical conductivity and COD. The correlation between these parameters can be easily found (Figure 3). Values of COD and conductivity in water flowing to the landfill (piezometers P1 and P2) are lower than in water flowing out from the landfill (piezometers P3 and P4). However, this is not a situation observed during the whole period of research, nor for all contaminants analyzed.

In some cases water from piezometer P2 had the highest or very high values, e.g. for CODCr. Observation of the landfill during sampling was helpful in interpretation of such a state. It was found that after heavy precipitations leaks occur through the embankment of the landfill from the pond of drain – on its western side (Figure 2). A portion of this water penetrates into the drain pond, but it does not affect concentrations of contaminants in the pond. It was also observed that a significant portion of leaks found its way out along the access road to the landfill quarter, according to the slope of terrain, to the vicinity of piezometer P2. Soaking in the ground, these leaks cause contamination of water in this piezometer. Therefore piezometer P2 should be excluded from interpretation of measurement results untill the western enbankment would be sealed and subsurface water in the vicinity of this piezometer would purify spontaneously.

Instances of high or the highest values of contaminants concentration (e.g. mercury) were also found in piezometer P1. It proves that some more contaminated water flows into the landfill, causing increased contaminants content in piezometers P3 and P4.

Influence of waste on subsurface water should be interpreted on the ground of correlation between concentrations of contaminants in eluates from the pond and in water from piezometers located in the vicinity of the outlet from the landfill (P3 and P4). Such a situation in water quality can be observed in case of CODCr and specific electrolytic conductivity.  It is additionally confirmed by similar tendency in changes of contamination of water from these piezometers and in drains from the pond.

In general evaluation of changes in contamination during the period of observation only small effect of the landfill on water environment was observed.

Observation of tendencies in changes of contaminants concentration during the last year of research demonstrated the increase of subsurface water contamination with nickel and organic compounds (CODCr), as well as the increase of salinity, measured as the specific electrolytic conductivity.

Concentrations of examined contaminants in subsurface waters (Figures 3 and 4) are lower or comparable to these in water extracts from raw waste (Table 2), what confirms rather slight influence of waste on subsurface water quality in the area of the landfill.

 

SUMMARY

Preliminary examination of raw waste, observation of changes in contaminant concentration in subsurface water, as well as observation of practices employed in landfill exploitation and waste/eluates management, taken altogether into consideration, create ground for proper interpretation of influence of waste on the water environment.

 

CONCLUSIONS

1.      Waste that comes into existence should be utilized to the highest possible degree, therefore minimizing the surface area and volume of the landfill, as well as minimizing its environmental impact (total load of contaminants and diversity of their indices).

2.      Post-production remainders should be deposited in the quarter of landfill and not be used directly in construction of embankments and ground levelling. Such materials do not thicken properly and are evidently leaky. They can also be a direct cause of subsurface water contamination.

3.      Enbankments of the landfill should be sealed and the drainage of eluents made passable. This will enable to avoid influence of leaks on subsurface waters.

4.      Careful choice of location of monitoring piezometers will enable to create actual view of contamination background and explicit interpretation of changes and influence of waste on the environment.

 

References:

1.    Industrial Waste Treatment Handbook. Second Edition. Woodard & Curran, Inc. Elsevier Inc., USA, 2006

2.    Dziennik Ustaw Rzeczypospolitej Polskiej Nr 62. Ustawa o odpadach. Poz. 628 z dnia 27 kwietnia 2001 r.

3.    Dziennik Ustaw Rzeczypospolitej Polskiej Nr 25 Ustawa o recyklingu pojazdów wycofanych z eksploatacji. Poz. 202 z dnia 11 lutego 2005r.

4.    Dziennik Ustaw Rzeczypospolitej Polskiej Nr 180. Ustawa o zużytym sprzęcie elektrycznym i elektronicznym. Poz. 1495 z dnia 29 lipca 2005 r.

5.      Dyrektywa 2006/118/WE Parlamentu Europejskiego i Rady w sprawie ochrony wód podziemnych przed zanieczyszczeniem i pogorszeniem ich stanu. Dziennik Urzędowy Unii Europejskiej L 372/19 z dnia 12 grudnia 2006 r.

6.      Tadeusz Marcinkowski, Wojciech Słomka.  Badania, ocena i opracowanie sposobów wykorzystania ziemi jako frakcji mineralnej powstałej przy sortowaniu złomu
Raport Serii SPR Nr 14 /2001 Instytut Inżynierii Ochrony Środowiska Politechniki Wrocławskiej.2001 r.

7.      Dziennik Ustaw Rzeczypospolitej Polskiej Nr 32. Rozporządzenie Ministra środowiska w sprawie klasyfikacji dla prezentowania stanu wód powierzchniowych i podziemnych, sposobu prowadzenia monitoringu oraz sposobu interpretacji wyników i prezentacji stanu tych wód. Poz. 284. z dnia 11 lutego 2004 r.

8.      Tadeusz Marcinkowski, Wojciech Słomka. Badania i ocena wód piezometrycznych i wody ze stawu odciekowego w rejonie składowiska odpadów ze strzępienia złomu. Prace niepublikowane Instytutu Inżynierii Ochrony Środowiska Politechniki Wrocławskiej z badań z lat 2003-2007.