A Study on the Effect of Chemical Remediation and Phytoremediation on Soils Contaminated by Hospital Waste, Chemical Fertilizers and Slurry Waste

A Study on the Effect of Chemical Remediation and Phytoremediation on Soils Contaminated by Hospital Waste, Chemical Fertilizers and Slurry Waste

Febina A Manaf Post Graduate student

Geotechnical Engineering St.Thomas Institute for ScienceandTechnology

Trivandrum,Kerala,

Susan K Santy Post Graduate student

Geotechnical Engineering

St. Thomas Institute for Science and Technology Trivandrum, Kerala

Abstract Soil contamination has now become one of the major concerns over the past few decades. It has increased the concern over help and ecological imbalance, which has lead to the need for cost-effective remediation techniques for soil contamination. The use of plants and introduction chemical oxidants to contaminated soils are found to be extremely effective degrading several types of contaminants including polyaromatic hydrocarbon (PAH), high organic contents, metal concentrations, chlorinated compounds, polyvinyl chloride (PVC) and others. This paper deals with studying three types of contaminated soils, viz; Hospital waste contaminated soils, chemical fertilizer contaminated soil and slurry waste contaminated soils and their remediation techniques using chemical reagents including Condys crystals and sodium Hydroxide and phytoremediation using Arrowroot plants. It was found that chemical reagents are more effective than phytoremediation in concern with contaminant reduction and time. Remediation using Condys crystals gave best effective results than with other two remediation techniques for the differently contaminated soils.

Keywords Condys crystals, phytoremediation, chemical reagents, contaminants,chmical fertilizers, slurry

1. INTRODUCTION

   Soil contamination is defined as the changes in the soil properties due to the accumulation and build-up in soils of harmful substances including toxic compounds, chemicals, disease causing agents, salts, radioactive materials, pharmaceutical leftovers which cause adverse effect on the plant and animal lives. Soil pollution can retard the plant growth, cause health issues to the animals and affect the useful microorganisms present in the soil. The sources of soil pollution include wastes from industries, household areas, hospitals, kitchen wastes, ,nuclear plants and fertilizer using agricultural areas and so on.

   The wastes from hospitals, agricultural areas, and household activities are the commonly met soil contaminants. Thus there arise a need to study about the soil contamination due to above mentioned wastes and to implement cost- effective remediation techniques, which gain commercial acceptance. Chemical analysis of the contaminated soils indicated that organic compounds ,polyaromatic hydrocarbons (PAH),Polyvinyl chloride (PVC),chlorinated compounds,

   metals, pharmaceutical leftovers were present in the three samples containing hospital waste, chemical fertilizers and slurry waste taken for the analysis.

   Since the amount of contaminants is more the remediation has to be done to these soils, that too in a cost effective way. Here both chemical remediation and phytoremediation techniques are used for the study. Condys crystals and Sodium hydroxide were used as the chemical reagents for the study. Condys crystals are promising when the contaminants are amenable to their mineralization to water and Carbon dioxide or oxidation to a less harmful product, which enables subsequent treatment. The relative oxidation power of Permanganate ion is 1.24. it when reacts with organic compound produce Manganese dioxide and Carbon dioxide. Sodium hydroxide is useful in degrading metal concentration present in the soil and other organic compounds. Phytoremdiation is done to the soil for a period of 3.5 months. Arrowroot plant is used for the purpose of study.

   In this study an attempt is made to determine the efficiency of three remediation techniques in degrading the contaminants of three different soils contaminated with hospital waste, chemical fertilizer and slurry waste.

2. OBJECTIVE OF THE STUDY

   • To determine the amount and type of contaminants present in the three types of soils.

   • To perform suitable remediation techniques for the contaminated soils.

   • To find out the most efficient method of remediation among the three methods.

3. MATERIALS AND METHODS

   1. Materials

      Both contaminated and uncontaminated soil samples of each type were collected purpose of study. All three samples were collected from a depth of 0.5m at spacing of 0.5m from their respective sites and mixed thoroughly to get a uniform mix.

      Soil sample 1: Soil samples were collected from an area where the wastes from a Multispecialty hospital at Trivandrum area are dumped in heaps before it goes into the

      treatment plant. The contaminated samples were collected as mentioned above. Uncontaminated samples were collected from a distance of 3 km away from the contaminated site from a depth of 0.5m at a spacing of 0.5m

      Soil sample 2: Soil samples were collected from an area where excessive amount of chemical fertilizers are used for agricultural purpose at Pallickal, Trivandrum. The soil here is polluted with high doses of fertilizers. The fertilizer used in this type of soil is FACTOMFOS (Ammonium Phosphate Sulphate). Sample collection was carried out according to the above mentioned way. Uncontaminated samples were collected from a distance of 1km away from the contaminated site at a depth of 0.5m at a spacing of 0.5m. Table 1 shows the chemical composition of the fertilizer.

      TABLE1. CHEMICAL COMPOSITION OF FERTILIZER

      MINERAL	AMOUNT (%)
      Nitrogen	20
      Phosphorous	20
      Sulphur	13
      Ammonium Phosphate	40
      Ammonium Sulphate	60

      Soil sample 3: The slurry waste contaminated soil samples were collected from a housing colony sharing same biogas plant at Pallickal, Trivandrum. All types of kitchen wastes and garbages excluding plastics and shells, goes into the plant. The organic content of such soils will be very high. Samples were collected according to the above mentioned way. Uncontaminated samples were collected from a distance of 1 km away from the contaminated site from a depth of 0.5m at a spacing of 0.5m. Table 2 shows the properties of slurry that contaminates the soil. 50ml of slurry was collected for 7days and mixed to get a uniform fluid.

      TABLE 2. PROPERTIES OF SLURRY

      PROPERTY	VALUE
      pH	7.4
      Solids (%)	12
      Ammonia (g/l)	0.9
      Nitrogen (g/l)	3
      Phosphorous (g/l)	2.75
      Volatile acids (g/l)	5.25
      BOD (g/l)	1200

   2. Properties of the representative soil samples

      pH of the selected soil samples, both contaminated and uncontaminated soils were determined by standard methods. Specific gravity of the three soil samples were determined according to IS: 2720(part 3 Bureau of Indian standards 1980 a). Atterberg limits of the representative soil samples were found out according to IS 2720 part 5, (Bureau of Indian standards1985 b) and IS 2720 (part 6 Bureau of Indian

      standards 1972). Particle size distributios of soil samples were determined according to IS2720 (part 4 Bureau of Indian standards 1985a). The standard proctor compaction test was done according to IS 2720(part 7 Bureau of Indian standards 1980b). Table 3, Table 4, Table 5, shows the properties of both contaminated and uncontaminated samples.

      TABLE 3.INDEX PROPERTIES OF SOIL SAMPLE 1

      PROPERTY	UNCONTAMINATED SAMPLE	CONTAMINATED SAMPLE
      pH	6.2	4.5
      Specific Gravity	2.55	2.97
      Liquid limit	42	50
      Plastic limit	30	25
      Plasticity index	37	55
      Shrinkage limit	22	15
      Grain size distribution
      Sand	58.8	30
      Silt	25	45
      Clay	16.2	24
      Compaction characteristics
      Maximum dry density(mg/m3)	1.2	1.37
      Optimum moisture content (%)	36	30

      TABLE 4.INDEX PROPERTIES OF SOIL SAMPLE 2

      PROPERTY	UNCONTAMINATED SAMPLE	CONTAMINATED SAMPLE
      pH	5.5	4.23
      Specific Gravity	1.9	2.55
      Liquid limit	40	50
      Plastic limit	30	25
      Plasticity index	14.6	21.9
      Shrinkage limit	22	10
      Grain size distribution
      Sand	30.6	27.7
      Silt	50.2	40.2
      Clay	19.2	30.1
      Compaction characteristics
      Maximum dry density(mg/m3)	1.43	1.26
      Optimum moisture content (%)	22	30

      TABLE 5.INDEX PROPERTIES OF SOIL SAMPLE 3

      PROPERTY	UNCONTAMINATED SAMPLE	CONTAMINATE D SAMPLE
      pH	6.0	4.7
      Specific Gravity	2.01	2.7
      Liquid limit	55	75
      Plastic limit	32	25
      Plasticity index	25.5	40.15
      Shrinkage limit	21.7	13
      Grain size distribution
      Sand	50.8	55.7
      Silt	32.1	28.1
      Clay	17.1	27.6
      Compaction characteristics
      Maximum dry density(mg/m3)	1.25	1.45
      Optimum moisture content (%)	21	25

   3. Preparation of soil samples for chemical analysis

      The soil samples collected were dried under shade by spreading them on plastic sheet s on ground. These air-dried samples were then sieved and soil passing through 2.00 mm sieve was taken for the analysis. These three samples were then mixed with the chemical reagents.300g of each soil sample were taken and mixed with 200 ml of Condys crystal solution. Condys crystals solution was prepared by mixing 10g of Condys crystals with 200 ml of distilled water. The prepared solution was kept in a beaker. 150g of the mixture was kept in a beaker and left undisturbed for a period of 1 week. Another 150gg mixture was kept in another beaker and left undisturbed for a period of 2 weeks. The reaction taking place between the soil contaminants and Condys crystals are represented as follows.

      R+KMnO4 > MnO2 +CO2 or Rox + others R Organic contaminant

      Rox – Oxidized intermediate organic compounds

      Soil 1, Soil 2 and Soil 3 were mixed with Sodium Hydroxide in the next set of treatment. 300g of each soil sample were mixed with 150ml of 0.1N Sodium Hydroxide solution and kept in a beaker for further analysis. 150g of soil- sodium hydroxide mixture is kept in a beaker and left undisturbed for 1 week and another 150g of same mixture was kept in a beaker and left undisturbed for 2 weeks. The reaction taking place between sodium hydroxide and soil contaminants are as follows.

      R+NaOH > NaR +H2O

      R Organic contaminants

      The three soil samples were also given phytoremedation. Arrowroot plants were used for the purpose of study, since

      they have very good contaminant absorption capacity. 3 kg of the representative samples were taken in a grow bag and single arrowroot plants were planted in it.

   4. Chemical analysis of soil samples

   Soil pH was determined using a standard pH meter according to IS: 2720(part 26, 1987). The ratio of soil to water ratio taken is 1:2.5. The salinity of the samples were determined using a conductivity meter with soil to water ratio 1:1.5. The organic carbon content of the soil samples were determined according to IS: 2720 (part 22, 1972). Cation exchange capacity was determined according to IS: 2720 (part 24, 1976).total soluble sulphates were determined according to IS: 2720 (part 27, 1977). Total nitrogen content was determined according to IS: 14684, 1999) using Macro- kjeldhals flask method. The Phosphorous content was determined according to IS: 5305, 1969. The amount of potassium and sodium were determined using a Flame photometer. Figure 1 shows the soil samples mixed with Condys crystals and Figure 2 shiws the soil samples mixed with NaOH solution.

   Figure 1. Soil Samples mixed with Condys Crystals

   Figure 2. Soil samples mixed with NaOH

4. RESULTS AND DISCUSSIONS

   The soil samples kept for chemical analysis using two reagents were analyzed after two weeks and four weeks. The chemical analysis results are given in Table 6, Table 7 and Table 8.

   Table 6 gives the results of first chemical analysis done to determine the amount of contaminants present in each type of soil before the treatment. Both normal soils samples and contaminated soil samples were given for the analysis. This analysis gives an idea about the extent of contamination in the three types of contaminated soils. Here TCC represents Total Carbon Content, CEC represents Cation Exchange Capacity, N represents Nitrogen content, P represents Phosphorous content, K represents Potassium content. NS denotes normal soil in all cases, HWS denotes Hospital Waste contaminated soil , CFS denotes Chemical fertilizer contaminated soil and SWS denotes Slurry Waste contaminated soils.

   Table 7 gives the results of chemical analysis of Hospital

   TABLE 6. CHEMICAL ANALYSIS OF SOILS BEFORE TREATMENT

   Table 11 and 12 gives the chemical analysis results of slurry waste contaminated soils using Condys crystals and NaOH respectively after 2 weeks and 4 weeks.

   Soil type	pH	Salinity mm/ho	TCC (%)	CEC (meq)	C:N ratio	P kg/h a	K kg/ha
   NS	6.2	2	0.76	75	25	50	22
   HWS	4.5	4	0.9	50	32	75	40		Time week	pH	Salinity mm/ho	TCC %	CEC	C:N ratio	P Kg/ ha	K Kg/ ha
   NS	5.5	1.7	0.66	60	23	65	25
   CFS	4.2	4.55	0.83	35	37	79	45
   NS	6.0	2.37	0.7	55	27	57	23		2	5.5	3.9	0.98	75	31.3	64	38
   SWS	4.7	5.0	1.1	100	34.5	69	49		4	5.7	3.01	0.87	68	29	59	29

   TABLE 11 .CHEMICAL ANALYSIS OF SLURRY WASTE CONTAMINATED SOILS TREATED WITH CONDYS CRYSTALS

   Table 7 and 8 give the chemical analysis results of hospital waste contaminated soil with Condys crystals and NaOH after 2weeks and 4 weeks respectively.

   TABLE 7. CHEMICAL ANALYSIS RESULTS OF HOSPITAL WASTE CONTAMINATED SOILTREATED WITH CONDYS CRYSTALS

   Time week	pH	Salinity mm/ho	TCC %	CEC	C:N ratio	P Kg/h a	K Kg/ ha
   2	5.5	2.9	0.85	65	29	60	32
   4	5.9	2.5	0.80	71	27	54	28

   TABLE 8. CHEMICAL ANALYSIS RESULTS OF HOSPITAL WASTE CONTAMINATED SOIL TREATED WITH NaOH

   Time week	pH	Salinity mm/ho	TCC %	CEC	C:N ratio	P Kg/ ha	K kg/ ha
   2	5.3	3.2	0.88	63	33	65	37
   4	5.5	2.8	0.82	69	29	55	31

   Table 9 and 10 gives the chemical analysis results of chemical fertilizer contaminated soil treated with Condys crystals and NaOH respectively.

   TABLE 9.CHEMICAL ANALYSUS OF CHEMICAL FERTILIZER CONTAMINATED SOILS SOILS TREATED WITH CONDYS CRYSTALS

   Time week	pH	Salinity mm/ho	TCC %	CEC	C:N ratio	P Kg/h a	K Kg/h a
   2	4.9	3.01	0.75	48	30.1	73	36
   4	5.2	2.32	0.70	52	26.5	67	29

   TABLE 10.CHEMICAL ANALYSUS OF CHEMICAL FERTILIZER CONTAMINATED SOILS SOILS TREATED WITH NaOH

   TABLE 12. CHEMICAL ANALYSIS RESULTS OF SLURRY WASTE CONTAMINATED SOIL TREATED WITH NaOH

   Time week	pH	Salinity mm/ho	TCC %	CEC	C:N ratio	P Kg/h a	K Kg/ ha
   2	5.2	3.99	0.97	76	32.4	67	41
   4	5.6	2.98	0.83	70	28.1	60	33

   Table 13 gives the chemical analysis results of Hospital waste contaminated soils after phytoremediation taken at 1.5,2.5 and 3.5 months.

   TABLE 13 . PHYTOREMEDIATION RESULTS OF HOSPITAL WASTE CONTAMINATED SOILS

   Time week	pH	Salinity mm/ho	TCC %	CEC	C:N ratio	P Kg/ ha	K Kg/ ha
   1.5	4.9	3.7	0.87	49	30.7	72	36
   2.5	5.8	3.00	0.82	60	28.2	63	30
   3.5	6.5	2.5	0.78	69	26.4	57	28

   Table 14 gives the chemical analysis results of chemical fertilizer contaminated soils subjected to phytoremediation, taken at 1.5,2.5 and 3.5 months.

   Time week	pH	Salinity mm/ho	TCC %	CEC	C:N ratio	P Kg /ha	K Kg/ ha
   1.5	4.4	4.1	0.71	45	34.4	76	41
   2.5	5.6	3.4	0.69	57	30.1	71	35
   3.5	6.3	2.5	0.67	64	27.2	67	27

   TABLE 14 . PHYTOREMEDIATION RESULTS OF CHEMICAL FERTILIZER CONTAMINATED SOILS

   Time week	pH	Salinity mm/ho	TCC %	CEC	C:N ratio	P Kg/ ha	K Kg/ ha
   2	4.6	3.23	0.8	45.1	32.5	75	40
   4	5	2.57	0.73	53	28.7	69	33

   Table 15 gives the phytoremediation results of slurry waste contaminated soils taken at 1.5, 2.5 and 3.5 months.

   TABLE 15 . PHYTOREMEDIATION RESULTS OF SLURRY WASTE CONTAMINATED SOILS

   43

   Time week	pH	Salinity mm/ho	TCC %	CEC	C:N ratio	P Kg/ ha	K Kg/ ha
   1.5	5.0	4.3	0.9	36.7	32	65
   2.5	5.7	3.6	0.84	31.9	30.1	61	38
   3.5	6.6	2.9	0.79	28.7	28.3	58	32

5. CONCLUSION

ACKNOWLEDGEMENT

I am delighted in using this opportunity to express my sincere and solemn thanks to Dr. Usha Thomas, Principal, St.Thomas Institute for Science and Technology and Dr.Mariamma Joseph , Professor and Head of the Department of Geotechnical Engineering for the support given during the preparation of this journal.

I am highly indebted to Dr.Mariamma Joseph, Professor and Head of the department of geotechnical engineering for the valuable guidance, constant encouragement and creative suggestions offered during the preparation of this journal work.

Last but not the least I express my sincere gratitude to Almighty God who made this journal work flawless and trouble free.

• The analysis showed that Hospital waste contaminated soils are highly contaminated than the other two soils.

• Slurry waste soils have the least rate of contamination.

• From the results of chemical analysis done in the three samples, it was found that treatments with Condys crystals are more effective than the other two techniques of remediation.

• Treatment with NaOH is less effective than Condys crystals and more effective that phytoremediation in concern with time as a factor in certain cases.

• It was found that phytoremediation also gave reliable results for the three types of contaminated soils.

REFERENCES

1. E.Wcislo, Soil contamination with PAHs in . Polish journal of Environmental studies, volume 7, No.5 (1998),267-272.

2. Cheryl kluck and Gopal Achari: Chemical oxidation techniques for insitu remediation of Hydrocarbon impacted soils.

3. Thahseen A.S.Sayara; Bioremediation of polyaromatic hydrocarbons (PAHs) contaminated soil process evaluation through composition and anaerobic digestion approach.

4. Achugasim .O, Ojinnake C.M, Osuji L.C, potassium permanganate as an oxidant in remediation of soil polluted by Bonny light crude oil: Sky journal of Soil Science and Environmental management vol.3(2),4 -9

5. Insitu chemical oxidation using KMnO4 by U.S Department of Energy, September 1999