Removal of some Heavy Metals from Industrial Wastewater and Gray Water by using some Natural and Organic Materials

A study was conducted for knowing the quantity and quality of heavy metal ions adsorbed on surfaces of treatment materials used in treatment of polluted water and to know the most efficient in removal process. Study included conducting two experiments, the first is laboratory, which is treatment of two polluted waters, namely industrial water and gray water, using four natural treatment materials as filters, which are activated Charcoal, Eichhornia crassipes plant powder, Ceratophyllum plant powder, and Arundo donax plant powder. It used poles made of polyethylene with a length of 100 cm and a diameter of 10 cm equipped with a tap from bottom, a layer of glass wool was placed at bottom, and then treatment materials were placed on top of it at a height of 50 cm. A piece of gauze cloth was placed over it for filtering polluted water from solids. Polluted water was passed after being filtered from top of column and left for 24 hours for equilibrium, then filtrate was collected from bottom of column. Second experiment, it is liberation experiment for heavy metals adsorbed on treated materials, where heavy metals were extracted by a 0.005M concentration of DTPA solution. This process was repeated five times for same treatment material and concentration of heavy metals adsorbed was measured each time. Results showed the following: 1-High concentrations of heavy metals, each of Lead, Cadmium, Zinc and Nickel in industrial water, where they reached 5.190, 0.043, 3.727 and 0.371 mg L-1, respectively, exceeding the limits allowed by World Food and Health Organization for each of Cadmium, Zinc and Nickel, while concentrations of Lead is within internationally permitted limits. As for the gray water, concentrations of Cadmium excelled the internationally permitted limits, while concentrations of Lead, Zinc and Nickel were within internationally permitted limits. 2-Concentration of Lead and Cadmium in all materials used in bioremediation, with exception of coal, exceeded internationally permitted limits in plants. Concentrations of Zinc and Nickel in all materials used in bioremediation did not exceed the internationally permitted limits, while coal did not record the presence of Zinc and Nickel because it is a porous, burned carbonaceous material. 3-Increasing amount of heavy metals liberated from various treatment materials through bioreclamation process in first three extractions, then it began to gradually decrease in fourth and fifth extractions. The different treatment materials varied in amount of heavy metals released, and they can be arranged as follows in terms of amount released of heavy metals: Eichhornia crassipes plant powder > Ceratophyllum plant powder > activated charcoal > Arundo donax plant powder. 4-Highest amount of heavy metals was released from materials used in industrial water, then gray water for Lead and Cadmium, while treatment materials used in industrial water and then gray water excelled in amount released for elements Zinc and Nickel.


Introduction
Great development in various industries and technologies and chemical and environmentally hazardous waste they produce, as well as expansion of use pesticides, disinfectants and sterilization materials, what is thrown out of sewage and industrial wastewater and process of random proliferation of service workshops and all these activities lead to pollution of water sources, especially rivers and streams and internal channels of various types of pollutants, including toxic elements [1][2][3].Industrial waste, agricultural waste and sewage water are among the main sources of pollution of aquatic environment with many organic and inorganic pollutants and heavy metals when thrown into surface water without proper treatment.These pollutants change characteristics of natural water, heavy metals are considered dangerous pollutants due to their dangerous toxic effects on environment, and they are very harmful compounds due to their non-dissolving nature.It possesses vital properties that make it accumulate and concentrate in various organs of human and animal bodies [4].There is no doubt that the entry of heavy metals into aquatic environment causes an imbalance in ecosystem and poisons aquatic plants, fish and other living organisms in that environment.One of the most important sources of environmental pollution with heavy metals is releasing of factory waste and washing water, as well as sewage water directly to environment [5,6] in addition, many heavy metals accumulate in agricultural lands as a result of irrigation with untreated wastewater, which causes many health problems [7], which in turn are transmitted to human and animal bodies through feeding on plant crops contaminated with heavy metals [8].As a result, heavy metals will accumulate in human body automatically.Water is used in industry as raw materials or in production, and after its use for many purposes, it becomes waste (industrial wastewater).It differs from one factory to another, and it contains chemicals and toxic substances emitted from factories and hospitals.It emits foul and toxic odors when temperature rises.As for gray water, it is all used water generated from domestic use, except for sewage water.They are the ones that come from showers, bathrooms, dishwashing, sinks and kitchen sinks.Gray water from kitchens contains food residues and high amounts of oils, fats, and cleaning materials such as shampoo, soap, toothpaste, and other body care products.However, it may also contain disease-causing microorganisms, and some chemical elements are concentrated in gray water from laundries because it contains soap powders such as Sodium, Phosphate, and Nitrogen [9].[10], indicated that concentrations of heavy metals Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn were low in gray water and did not exceed critical limits.[11], showed the presence of a high percentage of heavy metals such as Lead, Cadmium, Iron and Manganese in irrigation water due to discharge of water from factories and hospitals.[12], demonstrated possibility of using Eichhornia crassipes plant powder in treatment of industrial wastewater, which proved to be highly efficient and less expensive than use of various physical and chemical methods.[13], showed that activated carbon is characterized by its high ability to adsorb pollutants to water and more quickly compared to other materials, and that adsorption of heavy metals on Charcoal is by forming complexes with active groups of OH -1 and COO -1 on surface of Charcoal, [14], also indicated high ability of Charcoal to adsorb ions of heavy metals such as Pb, Ni, Cd and other contaminated water due to large number of small pores present in its composition .Mechanism of adsorption of heavy metals on activated charcoal includes electrostatic interference, ion exchange, chemical precipitation, and complexation with active aggregates on surfaces of Charcoal particles.[15], found, when evaluating quality of industrial water coming out of Cotton textile factory in Al-Kadhimiya-Baghdad, that it was contaminated with Zn and Pb, which are among most common elements in textile waste, whose concentrations were 0.98 and 0.30 mg L -1 , respectively.[16], indicated that main elements contained in liquid waste of textile factory are Fe, Cu, Cd, Cr and Zn, which exceeded upper limits allowed by FAO/WHO (2007).[17], showed increased pollution with heavy metals, especially Pb, in soil of battery factories in Al-Waziriyah-Baghdad has exceeded internationally permitted limit.[18], showed that irrigation with water contaminated with heavy metals leads to accumulation of these elements in soil and makes it polluted.Process of draining contaminated water is difficult and relatively expensive, and there are many traditional treatment methods that are usually ineffective and expensive [19], therefore, many new technologies that are considered natural bio-alternatives have been used for easy cleaning elements from polluted water by adsorption method using biomass adsorbent.Use of low-cost adsorbents for treatment of contaminated water is currently recommended because adsorbents are usually available in large quantities and are therefore cost-effective and inexpensive [20].The biomass that has attracted most attention for sequestering element ions from water primarily includes agricultural residues such as rice husks [21], leftcorn cobs [22], among others.The research aims to know quantity and quality of heavy metal ions adsorbed on surfaces of treatment materials used in the treatment of industrial water and polluted gray water and to know most efficient in removal process.

Materials and Methods
Two laboratory experiments were conducted, the first to treat polluted water (industrial wastewater and gray water) and the second was a liberation experiment to know quantity and quality of ions adsorbed on surfaces of treatment materials.In the treatment experiment, natural and organic materials were used (as filters), which are activated charcoal, Eichhornia crassipes plant powder, Ceratophyllum plant powder, and Arundo donax plant powder.These materials were dried, ground and sifted with a sieve with a diameter of 4 mm.Solid polyethylene poles, 100 cm long and 10 cm in diameter, were used.Column is open from top and closed from bottom, and is equipped with a tap, in order to control the process of opening and closing column.A layer of glass wool was placed at bottom of column to avoid clogging tap first, and to avoid part of treatment material going down secondly.Then, treatment materials were placed on top of it (each separately) at a height of 50 cm.Columns were rammed well to maintain approximately equal weights.A piece of gauze cloth was placed on layer of treatment materials for filtering water from solid materials.Polluted water was passed after filtration with a piece of safari cloth to rid it of solid materials (hair or wool and other coarse solid materials), from top of column to fullness of column leaving a height of 3 cm from top and left for 24 hours for balancing process, treatment materials were replaced every two days , Then filtrate was collected in polyethylene tanks.As for liberation experiment, 10 gm of each dry treatment material was taken separately after its use in process of treating contaminated water, and it was treated with DTPA solution, concentration of 0.005M, and volume was completed to 100 ml, then samples were shaken for two hours and filtrates were separated from them.Concentration of heavy metals adsorbed each time.Total content of heavy metals (Cd, Pb, Ni, and Zn) in treatment materials was estimated after digestion of samples by mixture of the two acids HCLO 4 -H 2 SO 4 , and it was measured by atomic absorption spectrophotpmetry apparatus [23], (Table 1), concentrations of heavy metals in polluted water were estimated by atomic absorption spectrophotpmetry apparatus Table (2).

Concentration of some Heavy Metals in Materials used in Bioreclamation
Lead concentration for each of Eichhornia crassipes plant powder, Ceratophyllum plant powder, and Arundo donax plant powder was 66.78, 56.86, and 39.25 mg kg -1 dry matter, respectively, while Cadmium concentration was 1.86, 1.37, 1.05, and 0.044 mg kg -1 dry matter, for each of Eichhornia crassipes plant powder, Ceratophyllum plant powder, and Arundo donax plant powder and Charcoal, respectively ( table 1), concentration of Pb and Cd in all materials used in bioremediation, with the exception of Charcoal, excelled on internationally permissible limits in plants according to the World Food and Health Organization (WHO/FAO, 2007) of 5.00 mg kg -1 dry matter for Pb, and 0.20 mg kg -1 dry matter for Cd.As for Zn, its concentrations reached 53.49, 41.12, 28.50, and Ni 32.76, 24.21, and 19.85 mg kg -1 dry matter, for each of Eichhornia crassipes plant powder, Ceratophyllum plant powder, and Arundo donax plant powder, respectively.Concentration of Zn and Ni in all materials used in bioremediation did not exceed internationally permitted limits for plants (WHO/FAO, 2007) of 60 mg kg -1 dry matter for Zn and 67 mg kg -1 dry matter for Ni, while Charcoal did not record presence of Zn and Ni because it is a porous carbon material burnt.High concentrations of heavy metals in materials used in bioremediation is due to fact that most aquatic plants have a high ability to absorb heavy metals from water, and this is in line with what [24] mentioned, who showed that most aquatic plants have ability to absorb heavy metals in water and sediment by their roots and its ability to accumulate these elements in aquatic plants and used as a vital evidence for accumulation of heavy metals in water.Eichhornia crassipes plant powder excelled on Ceratophyllum plant powder and Arundo donax plant powder is due to its large vegetative and root system, and this is consistent with what [25], mentioned, which showed that Eichhornia crassipes plant powder has the ability to absorb some heavy metals from surrounding aquatic environment.

Heavy Metals in Polluted Water (Untreated)
Table 2 shows high concentration of heavy metals, (Pb,Cd ,Zn and Ni )in industrial water, as they reached 5.190, 0.043, 3.727 and 0.371 mg L -1 , respectively, and it exceeded critical limits allowed by World Food and Health Organization (WHO/FAO) 2007), As for the gray water, the concentrations of Pb, Zn, and Ni were within the internationally permitted limits, amounting to 4.491, 1.314, and 0.166 mg L -1 , respectively, except concentration of Cd, which exceeded internationally permitted limits of 0.01 mg L -1 , it reached 0.036 mg.L -1 .Increase in concentration of Pb,Cd , Zn, and Ni in polluted water, including industrial water, is due to the fact that most of this water is produced from wastes of industrial facilities, which contain heavy metals in different concentrations.This is consistent with what [26] mentioned, who showed that most factories deliberately dispose of their waste and the products of their industries, such as factory waste, oil derivatives, city waste, chemical fertilizers, pesticides, disease-causing organisms, and radioactive materials by dumping them into water such as oceans, seas, and rivers, so that water becomes less suitable for natural uses such as drinking and agriculture [27], showed that most important sources of Cadmium pollution are industry and mining, while gray water, high concentration of Cd in it is due to products and waste of laundry and cleaning water, such as soap, shampoo and brighteners, which contain Cadmium at a higher concentration than rest of studied elements.

Effect of Number of Times of Extraction on Concentration of Lead Released from Different Treatment Materials of Industrial Water
Table 3 shows the amount of Lead released for five consecutive extractions with aggregate amount extracted with a DTPA solution from different treatment materials of polluted industrial water, as it notes a general trend that represents a gradual decrease in amount of Lead released from treatment materials from first extraction to last, release speed of Lead was high In first, second and third extractions, then a gradual decline began until last extraction.This may be due to release of ions with low binding strength at beginning, which are in high quantities as a result of saturation, then ions with high binding strength are released, which are in a somewhat lower quantity.Eichhornia crassipes plant powder, reached 47.30, 33.15, and 25.06 mg Pb kg -1 dry matter, for first, second, and third extractions in succession, then decreased to 19.20 and 15.22 mg Pb kg -1 dry matter, for fourth and fifth extractions in succession, and so on for rest of treatment materials.Accumulated amount released was 139.93 mg Pb kg -1 dry matter.Ceratophyllum plant powder came second, accumulated amount released was 128.53 mg Pb kg -1 dry matter, then activated charcoal, accumulated amount released from Lead was 120.36 mg Pb kg -1 dry matter.Finally, Arundo donax plant powder, accumulated amount was 90.38 mg Pb kg -1 dry matter.Release of Lead is affected by degree of saturation of treated materials with Lead and its original content of element, and then amount released is greater when saturating with element is higher.
Table 3. Released Lead (mg kg -1 dry matter) for different industrial water treatment.

Processing materials
Released Lead (mg kg  1) on one hand, and its high adsorption capacity for heavy metals on other hand.These results are consistent with what [25], concluded, which showed high ability of Eichhornia crassipes plant to absorb heavy metals and accumulate them in their internal tissues.Ceratophyllum plant powder came second in terms of amount of Lead released.This may be due to relatively high Lead content of original plant (56.86 mg Pb kg -1 dry matter, Table 1) and its high ability to adsorb heavy metals.Activated charcoal was excelled on Arundo donax plant powder in increasing amount of Lead released.This may be due to high capacity of Charcoal in adsorption of heavy metals ions such as Lead, which leads to saturation of its pores with Lead, and then an increase in amount released from it upon extraction.This is consistent with what was found by [28], who indicated presence of active groups such as carboxyl group and phenol in charcoal, which increase adsorption process and thus increase amount released from element after extraction.Capacity and efficiency of activated charcoal powder in adsorption of heavy metals is greater than other used treatment materials, but Eichhornia crassipes plant powder and Ceratophyllum plant powder contains high levels of Pb in its tissues before use in treatment and increased amount of Pb adsorbed by them.It led to an increase and excelled of released amount of Lead compared to activated charcoal powder.

Effect of Number of Extraction Times on Concentration of Cadmium Released from Different Treatment Materials of Industrial Water
Table 4 shows gradual decrease in amount of Cadmium released from treatment materials from first extraction to last.This may be due to release of ions with low binding strength at the beginning, which are in high quantities as a result of saturation, then ions with high binding strength are released, which are somewhat less.When comparing the amount released of Cadmium from different treatment materials, we notice that highest amount released was in treatment with Eichhornia crassipes plant powder, accumulated amount released was 1.29 mg Cd kg -1 dry matter, and Ceratophyllum plant powder came in second place, accumulated amount released was 1.05 mg Cd kg -1 dry matter.Activated charcoal, came in third place, and accumulated amount released from Cd was 0.95 mg Cd kg -1 dry matter, finally, Arundo donax plant powder, accumulated amount was 0.63 mg Cd kg -1 dry matter.Increase in amount released when using Eichhornia crassipes plant powder may be due to high content of Eichhornia crassipes plant of Cadmium before experiment (1.86 mg Cd kg -1 dry matter, Table 1) on one hand, and its high ability to adsorb heavy metals on the other hand.These results are consistent with what has been reached by [25], which showed high ability of Eichhornia crassipes plant to absorb heavy metals and accumulate them in their internal tissues.Ceratophyllum plant powder came second in trait of amount of Cadmium released.This may be due to relatively high Cadmium content of original plant (1.37 mg Cd kg -1 dry matter, Table 1) and its high ability to adsorb heavy metals.This is in line with what [29], mentioned, who showed that Ceratophyllum plant has a high efficiency in removing heavy metals, including Cadmium, from polluted water.Activated charcoal was excelled on Arundo donax plant powder in increasing amount of released Cadmium,this may be due to high capacity of Charcoal to adsorb ions of heavy metals such as Cd, which leads to saturation of its pores with Cd, and then an increase in amount released from it upon extraction.This is consistent with what was found by [28], who indicated presence of active groups such as the carboxyl group and phenol in charcoal, which increase the adsorption process and thus increase the amount released from element after extraction.Efficiency of activated charcoal powder in adsorption of heavy metals is greater than other used treatment materials, but Eichhornia crassipes plant powder and Ceratophyllum plant powder contains high percentages of Cadmium in its tissues before use in treatment, and increasing amount adsorbed from Cadmium by them, led to an increase and exceeding amount released from Cadmium compared to activated charcoal powder.

Effect of Number of Extraction Times on Concentration of Zinc Liberated from Different Treatment Materials of Industrial Water
Table 5 shows gradual decrease in amount of Zinc released from treatment materials from first extraction to last, and when comparing amount released of Zinc from different treatment materials, highest amount released was in treatment with Eichhornia crassipes plant powder, accumulated amount released was 93.92 mg Zn kg -1 dry matter, while Ceratophyllum plant powder came in second place, accumulated amount released was 85.07 mg Zn kg -1 dry matter.Then activated Charcoal, where the accumulated amount of Zinc released was 83.89 mg Zn kg -1 dry matter.Finally, Arundo donax plant powder comes, accumulated amount reached 73.50 mg Zn kg -1 dry matter.Increase in amount released when using Eichhornia crassipes plant powder may be due to relatively high Zinc content of Eichhornia crassipes plant before experiment (53.49mg Zn kg -1 dry matter, Table 1) on one hand, and its high adsorption capacity for heavy metals on other hand.These results are consistent with what [25], concluded, which showed high ability of Eichhornia crassipes plant to absorb heavy metals and accumulate them in its internal tissues.Powder of Ceratophyllum plant comes second in terms of amount of Zinc released.kg -1 dry matter, Table 1) and its high ability to adsorb heavy metals.This is in line with what [30], found, which showed that Ceratophyllum plant has a high efficiency in removing heavy metals from polluted water, as he noticed that rate of its removal of heavy metals, including Zinc, is high, which led to an increase in bioaccumulation rate of heavy metals in plant tissues with an increase in period exposure to water contaminated with these elements, Activated charcoal excelled on Arundo donax plant powder in increasing amount of released Zinc.This may be due to high capacity of charcoal in adsorption of ions of heavy metals such as Zinc, which leads to saturation of its pores with Zinc, and then an increase in amount released from it upon extraction, due to the large number of pores and increase in area in which the process is carried out adsorption.

Effect of Number of Extraction Times on Concentration of Nickel Released from Different Treatment Materials of Industrial Water
Table 6 shows gradual decrease in amount of Nickel released from treated materials from first extraction to last.This may be due to release of ions with low binding strength at beginning, which are in high quantities as a result of saturation, then ions with high binding strength are released, which are in a somewhat lower amount.with Eichhornia crassipes plant powder, as accumulated amount released was 9.25 mg Zn kg -1 dry matter, Then powder of Ceratophyllum plant ranked second, accumulated amount released was 8.48 mg Ni kg -1 dry matter.Increase in amount released when using Nile flower powder may be due to the nickel content of Eichhornia crassipes before experiment (32.76 mg Ni kg -1 dry matter, Table 1) on one hand, and its high adsorption capacity for heavy metals on the other hand.These results are consistent with what [25], concluded, which showed high ability of Eichhornia crassipes plant to absorb heavy metals and accumulate them in their internal tissues.Ceratophyllum plant powder comes second in terms of amount of released Nickel, which may be due to Nickel content of original plant (24.21 mg Ni kg -1 dry matter, Table 1).andits high ability to adsorb heavy metals, and this is in line with what [30], mentioned, who showed that Ceratophyllum plant has a high efficiency in removing heavy metals from polluted water, as it was noted that removal rate for heavy metals, including Zinc, was high, and this increases rate of bioremediation of heavy metals in plant tissues with increasing time period for plant to exist in water contaminated with heavy metals, including Nickel.Excelled of activated charcoal over Arundo donax plant powder is noted in increasing amount of released Nickel, this may be due to high capacity of Charcoal in adsorption of heavy metals ions such as Nickel, which leads to saturation of its pores with Nickel, and then an increase in amount released from it upon extraction, due to large number of pores and increase adsorption area,this is consistent with what was indicated by Alwan et,al.(2009), who showed that activated carbon is characterized by its high ability to adsorb pollutants to water and more quickly compared to other substances.Efficiency of activated charcoal powder in adsorption of heavy metals is greater than other used treatment materials.However, presence of high levels of Ni in their tissues before use in treatment, and increase in amount of Nickel adsorbed by them, led to an increase and superiority of released amount of Nickel from them compared to activated charcoal powder.Table 6.Released Nickel (mg kg -1 dry matter ) for different greywater treatment materials.

Processing materials
Released Nickel (mg kg

Effect of the Number of Extraction Times on Concentration of Cadmium Released from Different Grey Water Treatment Materials
It is noted from Table 7 gradual decrease in amount of Cadmium released from treated materials from first extraction to last.Release speed of Cd was high in first, second and third extractions, then it began to gradually decrease until last extraction, this may be due to release of ions with low binding strength at beginning, which they are in high quantities as a result of saturation, then ions with high binding strength, which are somewhat less, are released.When comparing released quantity of Cd from different treated materials, it notice that highest amount released was in treatment with Eichhornia crassipes plant powder, where accumulated amount released was 0.97 mg Cd kg -1 dry matter, then came powder of Ceratophyllum plant in second place, accumulated amount released was 0.83 mg Cd kg -1 dry matter.As for activated charcoal, it ranked third in terms of amount of Cd released.Acumulative amount released from Cd was 0.76 mg Cd kg -1 dry matter.Arundo donax plant powder came in last place, as accumulated quantity was 0.41 mg Cd kg -1 dry matter.Increase in amount released when using Eichhornia crassipes plant powder may be due to high content of Eichhornia crassipes plant of CD before experiment (86 mg Cd kg -1 dry matter, Table 1) on the one hand, and its high ability to adsorb heavy metals on the other hand, these results are consistent with what [25], has reached., who showed high ability of Eichhornia crassipes plant to absorb heavy metals and accumulate them in their internal tissues.Activated charcoal came in third place, and accumulated amount of Nickel released was 7.98 mg Ni, kg -1 dry matter.As for plant powder, Arundo donax plant powder comes in the last rank, as the accumulated amount reached 7.34 mg Ni kg -1 dry matter.Powder of Ceratophyllum plant came second in terms of amount of Cd released, this may be due to relatively high Cadmium content of original plant (1.37 mg Cd kg -1 dry matter, Table 1) and its high ability to adsorb heavy metals,this is in line with what [30], concluded, which showed that Ceratophyllum plant has a high efficiency in removing heavy metals from polluted water, as it was noted that removal rate was high for heavy metals, including Cadmium, so bioremedation rate of heavy metals in plant tissues increases with increase of the time period exposure to polluted water.Activated charcoal was excelled on Arundo donax plant powder in increasing the amount of Cadmium released, and this is consistent with [28], who indicated presence of active groups such as carboxyl group and phenol in charcoal, which increase adsorption process and thus increase amount released from element upon extraction.Efficiency of powder Activated charcoal in adsorption of heavy metals is higher than other treatment materials used.However, presence of high levels of Cadmium in tissues of the Eichhornia crassipes plant and Ceratophyllum plant before use in treatment, and increasing amount adsorbed of Cadmium by them, led to an increase and superiority of amount released of Cadmium from them compared to activated charcoal powder.Table 7. Released Lead (mg kg -1 dry matter) for different greywater treatment materials.

Processing materials
Released lead (mg kg

Effect of Number of Times of Extraction on Concentration of Nickel Released from Different Treatment Materials of Gray Water
Table 9 shows gradual decrease in amount of Nickel released from treated materials from first extraction to last.When comparing amount of Nickel released from different treated materials, note that highest amount released was in using treatment with Eichhornia crassipes plant powder.Accumulated amount released was 4.78 mg Ni kg -1 dry matter, and Ceratophyllum plant powder came second, accumulated amount released was 4.25 mg Ni kg -1 dry matter, then activated Charcoal, where accumulated amount released from Nickel was 3.79 mg Ni kg -1 dry matter.Finally, Arundo donax plant powder, total amount was 3.03 mg Ni, kg -1 dry matter.Increase in amount released when using Eichhornia crassipes plant powder may be due to Nickel content of Eichhornia crassipes plant before experiment (32.76 mg Ni kg -1 dry matter, Table 1) on the one hand, and its high adsorption capacity for heavy metals on the other hand, these results are consistent with what has been reached [25], who showed high ability of Eichhornia crassipes plant powder to absorb heavy metals and accumulate them in their internal tissues.Powder of Ceratophyllum plant, it came second in terms of amount of released Nickel, this may be due to content of original plant of Nickel (24.21 mg Ni kg -1 dry matter, Table 1) and its high ability to adsorb heavy metals, this is in line with what [30] showed, who showed that Ceratophyllum plant has a high efficiency in removing heavy metals from polluted water, as it was noted that removal rate was high for heavy metals, including Nickel, so bioremedation rate of heavy metals in plant tissues increases with increase in time period of exposure to water contaminated, Activated charcoal excelled on Arundo donax plant powder in increasing amount of released Nickel, this may be due to high capacity of Charcoal in adsorption of ions of heavy metals such as Nickel, which leads to saturation of its pores with Nickel and then an increase in amount released from it upon extraction, due to large number of pores and increase in adsorption area, this is what it is consistent

Table 1 .
Concentration of some heavy metals in materials used in bioremedation.

Table 2 .
Concentrations of heavy metals (mg L -1 ) in polluted water used in agriculture.

-1 ) dry matter Number of extraction times first second third Fourth Fifth Cumulative quantity
Increase in amount released when using Eichhornia crassipes plant powder may be due to high lead content of Eichhornia crassipes plant before experiment (66.78 mg Pb kg -1 dry matter, Table

Table 4 .
Released Cadmium (mg kg -1 dry matter) for different industrial water treatment.

Table 5 .
This is consistent with whatAlwan et, al. (2009)found, who showed that activated carbon is characterized by its high ability to adsorb pollutants to water and more quickly compared to other materials.Efficiency of activated charcoal powder in adsorption of heavy metals is greater than other used treatment materials.However, presence of high percentages of Cadmium in tissues of Eichhornia crassipes plant and Ceratophyllum plant before use in treatment, increase in amount of Zinc adsorbed by them, led to an increase and excelled of amount released of Zinc from them compared to activated charcoal powder.Released Zinc (mg kg -1 dry matter) for different industrial water treatment.

-1 dry matter) Number of extraction times First Second Third Fourth Fifth Cumulative quantity
(30)ct of Number of Times of Extraction on Concentration of Zinc Released from Different Treatment Materials of Gray WaterTable8indicates gradual decrease in general of amount of Zinc released from processed materials from first extraction to last, highest amount released was in treatment with Eichhornia crassipes plant powder, where accumulated amount released was 31.14 mg Zn kg -1 dry matter, while powder of Ceratophyllum plant comes second, accumulated amount released was 28.72 mg Zn kg -1 dry matter.Then activated charcoal, acumulative amount released from Zinc was 24.50 mg Zn kg -1 dry matter, and finally Arundo donax plant powder, as acumulative amount reached 13.49 mg Zn kg -1 dry matter.Increase in amount released when using Eichhornia crassipes plant powder may be due to relatively high Zinc content of Eichhornia crassipes plant before experiment (53.49mgZn kg -1 dry matter, Table1) on the one hand, and its high ability to adsorb heavy metals on the other hand.Results are consistent with what[25], concluded, who showed high ability of Eichhornia crassipes plant to absorb heavy metals and accumulate them in their internal tissues.Ceratophyllum plant powder comes second in terms of amount of released Zinc, this may be due to original plant's Zinc content (41.12 mg Zn kg -1 dry matter, Table1) and its high adsorption capacity for heavy metals,this is in line with what(30)found, who showed that Ceratophyllum plant is efficient in removing heavy metals, including Zinc, from polluted water.Therefore, rate of bioremedation of heavy metas in plant tissues increases with increase in time period of exposure to polluted water.Activated charcoal was superior to Arundo donax plant powder in increasing amount of released Zinc, this is consistent with results Alwan et,al.(2009),who showed that activated carbon is characterized by its high ability to adsorb pollutants to water and more quickly compared to other materials.Efficiency of activated Charcoal powder in adsorption of heavy metals is higher than other used treatment materials .However, presence of high percentages of Zinc in tissues of Eichhornia crassipes plant and Ceratophyllum plant before use in treatment, and increase in amount of Zinc adsorbed by them, led to an increase and superiority of amount released Zinc from them, compared to activated Charcoal powder.

Table 8 .
Released Zinc (mg kg -1 dry matter) for different greywater treatment materials.

Table 9 .
IOP Publishing doi:10.1088/1755-1315/1259/1/01200310withwhat was mentioned by Alwan et, al. (2009), who showed that activated carbon is characterized by its high ability to adsorb pollutants to water and more quickly compared to other substances.Efficiency of activated Charcoal powder in adsorption of heavy metals was greater than that of other used treatment materials.However, Eichhornia crassipes plant powder and Ceratophyllum plant contained high levels of Nickel in its tissues before use in the treatment, and increase in amount of Nickel adsorbed by them, led to an increase and exceeding amount released from Nickel compared to activated Charcoal powder.Released Nickel (mg kg -1 dry matter) for different grey water treatment materials.