الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 313 |  |  |
| | | from | 313 | | |
Abstract
The quantities of sewage sludge in Egypt are about 4 million tons annually, and this sludge represents a big problem if it is not treated and disposed of in a healthy and safe manner. In Egypt, using what is known as sludge drying basins, where liquid sludge is pumped into basins with very large areas and small depths of no more than 40-60 cm.
This is for the purpose of drying it by evaporating water from it naturally and filtering it through a layer of sand at the bottom of the drying basins. This method is characterized by ease of operation and low operating costs, but it requires huge areas that may reach 42.4, -52% of the total area of the station in traditional stations such as stations that they depend on the activated sludge system, and the lack of space required for drying basins which may constitute an obstacle to expanding the capacities of the existing stations in almost all central stations in Egypt.
The sewage sludge can also be dried by other mechanical methods, but these methods are disadvantaged by the very high construction and operating costs, in addition to their needs for skilled and trained labor to operate them, so there was a need for an easy-to-operate and inexpensive system that suits the Egyptian conditions in addition to the possibility of applying it to increase the capacity of drying sludge in the existing stations without increasing Large in cost, so this research aims to study the possibility of using phytoremediation to increase the drying rate of sludge compared to traditional drying basins protectors in agriculture. Therefore, this research was carried out by conducting four experiments:
• The first experiment:
This experiment aimed to the study the four (4) plant types cultivated in pond filled with sewage sludge only and or plus with biochar in order to determine the rate of growth of the investigated plants. Also, the ability of the growing studied plant to absorb the sludge, and to how range remove the metals from the sewage sludge (growth media). The number of ponds that used in this experiment are (10 ponds) including one of them filled with sewage sludge effluents only. The same five ponds were filled with other with the sludge effluents repeated beside addition of biochar (1 g/L). For the cultivated ponds (8 ponds), each of the studied plants cultivated separately (one plant type in each pond) as 18 plants of each in a pond.
• Second experiment:
This experiment is aimed to study the ability of every two different plants to grow in each pond. The number of ponds that used in this experiment are 12 ponds, six of them filled with sludge effluents only and the other 6 ponds filled with sludge effluents plus 1g biochar / L (200g / 200L) in each pond.
• The third experiment:
This experiment is aimed to study the ability of every three different plants together in each pond. The number of ponds that used in this experiment are (8 ponds), 4 pond of them filled with sludge effluents only, while the other 4 ponds filled with sludge effluents beside 1g biochar / L (200g / 200L) in each pond.
• Fourth experiment:
This experiment is aimed to study the growth of the studied 4 plant types when cultivated together in pot. The number of ponds that used in this experiment are (2 ponds), filled with sludge effluents only, while one of them treated with 1g biochar / L (200g / 200L) in each pond.
All experiments were carried out in ponds of 200 liters insulated against water leakage, which were filled with sludge effluents. A sample of sludge was taken from the sewage plant in Arab Abu Saed, Helwan, south of Cairo Governorate. Plants samples were also collected from the Zahra Canal Shatt in the village of
Al-Baslaqoun in the governorate the lake. The studied plant species are Common reed, Pardee, Sammar and Niseila as a total of 18 plants per each pond.
To determine the efficiency of plants and dehydration of the sludge, the weight of the removed water was measured every three days by measuring the weights of the plants and measuring the height of the sludge remaining in the ponds. The concentration of heavy metals (Cadmium - Lead - Zinc - Copper – Iron - chromium) measured in plants (shoots and roots) as well go the remaining sludge solid plant in the pond to determine the efficiency of each plant for growth at a coverage rate of 80% and in the removal of various elements.
The weight of plants was done every three days up to 48 days. The studied parameters were weight of plants every three days, the RGR (Relative Growth Rate), Volume of water removal, efficiency of dewatering in both plant and sewage sludge (Solid Phase) at the end of the experiment.
• RESULTS:
The obtained results revealed the following:
It may be found from the first experiment that all plants are initially affected by sewage sludge, which leads to a decrease in their weight at the beginning of the experiment. After that, the interaction of plants with the growth conditions in the sludge varies according to the type of plants.
1st experiment:
The highest weight ponds of studied plants are 5300 g for Sammar at 48 days,
4,200 g for Pardee at 48 days, 2950 g for Niseila at 36 days and 4542 g for Common reed at 6 days. At addition of biochar, the highest weight was 3,700 g for Sammar at 48 days, 3911 g for Pardee at 48 days, 2687 g for Niseila at 36 days and 6050 g for Common reed at 48 days.
At addition of biochar the weight of plants under all the studied periods decreased if compared with the weights of the same plants not treated with biochar.
The efficiency of dewatering at the end of experiment are 79, 83, 90 and 80% for Sammar, Pardee, Niseila and Common reed plants respectively.
The volume of water removal of the studied plants at the end of experiment are 157.5, 165, 180 and 160 L for Sammar, Pardee, Niseila and Common reed plants respectively. The correspond value for the studied plants at addition the biochar to ponds are 165, 135, 180 and 170 L.
The highest concentration of Cu is associated with Pardee, Fe, ZN and Pb with Niseila, Cd and Cr with Sammar plants. At addition of biochar the highest concentration of Cu, Cd and Pb with Pardee plants, Fe with Niesila, Zn and Cr with Niseila.
The highest concentration of studied elements in sewage sludge at the end of the experiment are in the following, Cu with Common reed plants, Fe, Cd and Cr with Niseila plants, and Zn and Pb with Pardee. At addition of biochar the correspond high value of elements associated with Cu, Zn and Cd with Common reed plants, Fe with Pardee plants, Pb with Sammar and Niseila plants and Cr with Sammar plants.
2nd experiment:
The highest weight pond when two plants cultivated in the same pond are 3240 g for (Niseila & Sammar) at 36 days, 5015 g for (Niseila & Pardee) at 39 days, 4231 g for (Niseila & Common reed) at 42 days, 6800 g for (Common reed & Pardee) at 48 days, 7600 g for (Common reed & Sammar) at 45 days and 7046 g for (Pardee & Sammar) at 45 days. At addition of biochar, the highest weight is 2431 g for (Niseila & Sammar) at 45 days, 2637 g for (Niseila & Pardee) at 45 days, 7450 g for (Niseila & Common reed) at 45 days, 7195 g for (Common reed & Pardee) at 45 days, 4979 g for (Common reed & Sammar) at 45 days and 7043 g for (Pardee & Sammar) at 45 days.
Addition of biochar indicated weights less than found for the same pond and plant through the studied period, when compared with untreated with biochar.
The efficiency of dewatering at the end of experiment are 90% for the (Niseila & Sammar, Niseila & Pardee and Niseila & Common reed), 85% for the (Common reed & Pardee) and 80% for the (Common reed & Sammar and Pardee & Sammar). at addition of biochar the value reached 83% for the (Niseila & Sammar), 78% for the for the (Niseila & Pardee) and (Niseila & Common reed), 75% for the (Common reed & Sammar), (Common reed & Pardee) and (Pardee & Sammar).
The volume of water removal of the studied plants at the end of experiment are 180 L for (Niseila & Sammar), 195 L for (Niseila & pardee), 180 L for (Niseila & Common reed), 160 L for (Common reed & Sammar), 170 L for (Common reed & Pardee) and 160 L for (Pardee & Sammar). At addition of biochar the obtained values are 165 L for (Niseila & Sammar), 155 L for (Niseila & pardee and Niseila & Common reed) and 150 L for (Common reed & Sammar, Common reed & Pardee and Pardee & Sammar).
The highest concentration of the studied elements varied from one element to another and according the plants type where the highest concentration of Cu, Fe, Zn and Cd are associated with (Niseila & Pardee), Pb with (Niseila & Common reed) and Cr with (Sammar & Niseila). At addition of biochar the highest concentration is associated with Cu with (Niseila & Sammar), Fe with (Sammar & Pardee), Zn with (Niseila & Sammar), Pb with (Niseila & Pardee), Cd with (Common reed & Sammar) and Cr (pardee & Common reed).
The highest concentration of the studied elements in sewage sludge at the end of experiment are Cu in pond cultivated with (Pardee & Sammar), Fe in pond cultivated with (Pardee & Common reed), Zn in ponds cultivated with (Sammar & Common reed and Pardee& Sammar), Pb in pond cultivated with (Common reed & Niseila), Cd and Cr in pond cultivated with (pardee & Niseila).
3rd experiment:
The highest weight pond when three of plant species cultivated together in pond are 5397 g for (Common reed & Niseila & Pardee) at 42 days, 5025 g for (Common reed & Sammar & pardee) at 33 days, 5236 g for (Common reed & Niseila & Sammar) at 42 days, 4797 g for (Niseila & Sammar & Pardee) at 36 days. at addition of biochar the correspond values are 5751 g for (Common reed & Niseila & Pardee) at 45 days, 7501 g for (Common reed & Sammar & pardee) at 45 days, 5226 g for (Common reed & Niseila & Sammar) at 42 days, 5099 g for (Niseila & Sammar & Pardee) at 42 days.
The efficiency of dewatering at the end of experiment are 85% for (Common reed & Niseila & Pardee and Niseila & Sammar & pardee) and 83% for (Common reed & Sammar & Pardee and Common reed & Niseila & Sammar). At addition of biochar, the obtained values are 73% for (Common reed & Niseila & Pardee), 80% for (Common reed & Sammar & pardee), 75% for (Niseila & Sammar & Pardee) and 78% for (Common reed & Niseila & Sammar).
The value of water removal of studied plants at the end of experiment are 170, 165, 135 and 165 L for (Common reed & Niseila & Pardee), (Common reed & Sammar & pardee), (Niseila & Sammar & Pardee) and (Common reed & Niseila & Sammar) respectively. At addition of biochar, the corresponding values are 135 L for (Common reed & Niseila & Pardee), 160 L for (Common reed & Sammar & pardee), 150 L for (Niseila & Sammar & Pardee) and 155 L for (Common reed & Niseila & Sammar).
The highest concentration of the studied elements are as follows: Cu in ponds cultivated with (Sammar & Common reed & Pardee), Fe in ponds cultivated with (Sammar & Common reed & Niseila), Zn in ponds cultivated with (Common reed & Niseila & Pardee), Pb, Cd and Cr in ponds cultivated with (Sammar & Pardee & Niseila). At addition of biochar, the value of Cu and Cd are associated with (Common reed & Niseila & pardee), Fe and Cd are associated with (Sammar & Common reed & Pardee), Zn is associated with (Sammar & Common reed & Niseila) and Cr is associated with (Sammar & Pardee & Niseila).
The highest concentration of studied elements in sewage at the end of experiment are showed that the pond cultivated of (Sammar & Pardee &Niseila) indicated the high value of all the studied elements (Cu, Fe, Zn, Pb and Cd), while the pond cultivated with (Common reed & Niseila & Pardee) indicated the higher Cr concentration compared with the combined plants. At addition of biochar the highest concentration of the studied elements Cu and Pb for (Sammar & Pardee & Niseila), Fe, Cd and Cr for (Common reed & Niseila & Pardee) and Zn for (Sammar & Common reed & Pardee).
4th experiment:
The highest weight of the studied plants when all of the (4 plant species) cultivated in the pond either treated with biochar or no treated.
Addition of biochar led to decrease the weight of plants throughout the studied growth period if compared with plants when cultivated in the pond filled with sludge effluent only.
The efficiency of dewatering at the end of the experiment indicated 83% even the ponds treated or untreated with the biochar.
The volume of water removal at the end of experiment 165 L and 185 L for plants cultivated in ponds untreated and treated with biochar respectively.
The highest concentration of the studied elements was observed for
Fe > Zn > Cu > Pb > Cd > Cr, where addition of biochar indicated the arrangement Zn > Fe > Cu > Pb > Cd > Cr.
Addition of biochar showed higher concentration of Cu, Zn, Pb and Cr compared with plants cultivated in the pond untreated with the biochar, while Fe and Cr took the opposite trend.
The concentration of studied elements in sewage sludge at the end of the experiment in the ponds treated with biochar showed higher value for Cu and Cd, while the elements (Fe, Zn, Pb and Cr) took the opposite trend when compared the concentration of these elements in the filled with sludge effluents only.
The uptake of the studied elements showed different patterns compared with their depending on plant type and the combined of plants (double or triple or all of plants together).
Also, the pH, Ec and TDS during the studied four experiments depending on time of sample and the addition of biochar and the type of plants cultivated.