A study on the main sewage channel in Erbil city Destiny and its matching to irrigation purpose

Studying the water quality of Erbil waste water, and how much it match with the world criteria to irrigation purpose, during Spring 2007 to Winter 2008 , ten stations within and along the city wastewater channel were chosen , the first formation (Qalaa in the city centre) till the last gathering station to form the main channel in the southern west of the city (Areb qand).Important measurements were taking in consideration :T. coliform, TP, TN, BOD5, COD and TSS .The main results were : * The seasonal values followed certain rhythm which was; Summer > Spring > Winter . * Only for the reason of high number of T. cliform in the studies season except the winter season which was in low value, the wastewater in the main channel match to irrigation purpose only in Winter season. Introduction Any comprehensive wastewater monitoring for controlling pollution degree ,some important indicators must be taken in consideration like ; five days biochemical oxygen demand ( BOD5 ), chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP), total coliform ,and total suspended solid (TSS).Because these are good indicators to the pollution degree of the wastewater which get municipal ,agricultural , and industrial discharge with high amounts of chemical pollutants such as N , P and C with high degree of oxygen demand,(chemical or biochemical) and biological by microbial pollutants such as faecal coliform. (Sonune & Gate, 2004; Sarioglu, 2005; Hussein, 2004; Henz et al., 2002; Viessman & Hammer,1996 and Upadhyay,2004). The area of Erbil city, which is about 150 square kilometers, according to WFP of Erbil sector (2002),the population of the city during that year was 589000an became 762,139 inhabitants in 2006 while it reaches 1491460 inhabitants in 2010.(Al-Naqshabandi,2002) . The necessity of water for different purposes of life has been doubled with progress development of Journal of Kirkuk University –Scientific Studies , vol.5, No.2,2010 62 technology and lifestyle in different areas. According to WFP of Erbil sector (2002) water requirement for domestic uses may reach to more than 320000 m 3 .d -1 , while water demand for agricultural and industrial uses was not estimated in Erbil city yet. The main source of water supply is the Greater Zab river (Ifraz project), in addition to more than 500 wells scattered within the city. Yet, Erbil city like many other cities in Iraq dose not have sewage treatment or pre treatment plant .So, this research is an attempt to understand Erbil’s wastewater destiny following its formation in the beginning in which mixing of many types of wastes; municipal, agriculture and industrial, till they gathered to form the main sewage channel in Twreq village, even after this point by several kilometers in (Areb qand village). And studying wastewater recovery by the action of so called self purification, then to compare these information with the world standards and how far it matching irrigation purposes, and as a result to establish database of Erbil’s waste water. Materials and Methods Description of the stations: Location of Areb qend ( station 10) is the north-western downtown by about 12 kilometers which is the final point, then discharged to Greater Zab river. The location of station (9) is in Tureq village which is a small village (about 50 small houses) , it is about 10 kilometers far from the city centre, and it collect only the villages wastewater and discharged it to the main pathway. Station (8) is about one kilometer above station (7).Station (7) is the gathering point branches and the formation of the main sewage pathway, it is about 9 kilometers down the city centre, Station (6) is collecting waste waters from (Alaskary quarter) and discharged to the main channel ,located just few meters before station 7. Station (5)is the main channel in the (Sailo quarter) and it is(5)kilometers down the city centre. Station (4) is the branch which collects the sewages from the previous station. Station (3), is the branch which collects the wastewater from the southern industry area located in south east of the city centre by (5) kilometers. Station (2) , is the (Runaky quarter) sewage branch , away from the city centre by (1.5) kilometers. Station (1) is the central of Erbil city (Qalaa quarter), it is the start point of the study and the highest elevation point of the city. (Figure, 1 shows the city and the studied stations allocation on Iraq satellite map). Journal of Kirkuk University –Scientific Studies , vol.5, No.2,2010


Introduction
Any comprehensive wastewater monitoring for controlling pollution degree ,some important indicators must be taken in consideration like ; five days biochemical oxygen demand ( BOD 5 ), chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP), total coliform ,and total suspended solid (TSS).Because these are good indicators to the pollution degree of the wastewater which get municipal ,agricultural , and industrial discharge with high amounts of chemical pollutants such as N , P and C with high degree of oxygen demand,(chemical or biochemical) and biological by microbial pollutants such as faecal coliform. (Sonune & Gate, 2004;Sarioglu, 2005;Hussein, 2004;Henz et al., 2002;Viessman &Hammer,1996 andUpadhyay,2004).
The area of Erbil city, which is about 150 square kilometers, according to WFP of Erbil sector (2002),the population of the city during that year was 589000an became 762,139 inhabitants in 2006 while it reaches 1491460 inhabitants in 2010. (Al-Naqshabandi,2002) . The necessity of water for different purposes of life has been doubled with progress development of technology and lifestyle in different areas. According to WFP of Erbil sector (2002) water requirement for domestic uses may reach to more than 320000 m 3 .d -1 , while water demand for agricultural and industrial uses was not estimated in Erbil city yet. The main source of water supply is the Greater Zab river (Ifraz project), in addition to more than 500 wells scattered within the city.
Yet, Erbil city like many other cities in Iraq dose not have sewage treatment or pre treatment plant .So, this research is an attempt to understand Erbil's wastewater destiny following its formation in the beginning in which mixing of many types of wastes; municipal, agriculture and industrial, till they gathered to form the main sewage channel in Twreq village, even after this point by several kilometers in (Areb qand village). And studying wastewater recovery by the action of so called self purification, then to compare these information with the world standards and how far it matching irrigation purposes, and as a result to establish database of Erbil's waste water.

Description of the stations:
Location of Areb qend ( station 10) is the north-western downtown by about 12 kilometers which is the final point, then discharged to Greater Zab river. The location of station (9) is in Tureq village which is a small village (about 50 small houses) , it is about 10 kilometers far from the city centre, and it collect only the villages wastewater and discharged it to the main pathway. Station (8) is about one kilometer above station (7).Station (7) is the gathering point branches and the formation of the main sewage pathway, it is about 9 kilometers down the city centre, Station (6) is collecting waste waters from (Alaskary quarter) and discharged to the main channel ,located just few meters before station 7. Station (5)is the main channel in the (Sailo quarter) and it is(5)kilometers down the city centre. Station (4) is the branch which collects the sewages from the previous station. Station (3), is the branch which collects the wastewater from the southern industry area located in south east of the city centre by (5) kilometers. Station (2) , is the (Runaky quarter) sewage branch , away from the city centre by (1.5) kilometers. Station (1) is the central of Erbil city (Qalaa quarter), it is the start point of the study and the highest elevation point of the city. (Figure, 1 shows the city and the studied stations allocation on Iraq satellite map).

Collecting of the samples
The sampling was began at 7 am from the first location and finished at 12 o'clock and the samples were collected in clean and dry polyethylene bags for the chemical analyses and in sterilized bottle for microbiological analysis. The analyses were started on the arrival to the laboratory immediately.

The analyses:
Total coliform: Counting of the most probable number (MPN) of faecal coliform was determined using the method described by APHA, (1998). Total Nitrogen: Total organic nitrogen was determined after digesting the samples using K 2 SO 4 then determined by microkjldahle method as described by Rump,(1999).And the nitrate was determined directly using Nitrachek instrument (from Hanna,Inc.).The two amounts were then collected and expressed as Total nitrogen in mg.l -1 Total phosphorus: Total phosphorus was determined as described in (Rump,1999). The amounts expressed in mg.l -1 Total suspended solids: It was determined using the procedure described in APHA, (1998) , The amounts expressed in mg.l -1 Biochemical oxygen demand (BOD 5 ): Determined as described in APHA, ( 1998). The amounts expressed in mg.l -1 Chemical oxygen Demand (COD): Chemical oxygen demand was determined after oxidation of organic matter in strong acid medium by K 2 MnO 4 . Results were expressed as mg.l -1 . COD. (Rump, 1999 ).

Results and Discussions
Total coliform; It is a group of microorganisms which are used as indicators to show the hygienic condition of the water, they are not pathogens by themselves but their appearance is an indicator to the pathogens (Cunningham and Saigo,2001), from table,2. And the graph, we found the Summer reading with high values and it reached 1600 cells /100ml water in three stations within the city,(Runaky, Askary Q. and Areb Qend), and dropped to 240 cells /100ml water , only in one occasion which was in an industrial area .Whereas in winter the value were too low and in many stations there were no detected ,even in spring the readings were so low but not as in winter states which ranged between (3-1200) cells /100ml water. Moreover the seasonal values followed certain rhythm which was; Summer > Spring > Winter due to the effect of the temperature and the evaporation action in the Summer, (Shekha, 2008). (Fig.2 and tables,1,2 and).    ,1978). It ranged between 0.00 -7.9mg/l( Industrial area and Runaky quarter, respectively) and it followed ascending increases which was the Summer with higher records then the Spring and the lowest records was going to the Winter. (Table,2  This rhythm with high records of Summer time may be due to the effect of the low levels of the wastewater in the Summer (certainly in the house area), so the detergents and the fertilizers concentrated in these season, while the industrial area gain lowest vales. (Round, 1972).
Our results were higher than what was found by other researchers who studied the area, (Shekha, 1994(Shekha, , 2008Ali, 2002 andAzez et al., 2001) and also from those who studied other places within Iraq wastewater, (Khamees,1979,and Rasheed,2008 who studied Sulaimanya sewage water). Still it can be used in irrigation purposes with regarding of this element , because there is not any limit of this element in the waste water. (W.H.O., 1993;Al-Radayda, 2002 andAl-Hussain , 2004).
(Mg/L) Total Nitrogen; Ranged with high variation which was between 5.85-57.80 mg/l (Klik mishik and Tureq village, respectively), the values followed ascending arrangement in the farm area differ from that arrangement of the house area, which in the first case was; Spring >Summer > Winter, and in the farm area the arrangement was; Summer >Spring > Winter, in which the reason goes to that in the farm area and because of the high use of the fertilizers by the farmers in the summer, which contains nitrogen element and discharged to the wastewater way, and the high values in the domestic area to discharge organic wastes rich with nitrogen, and these values decrease at winter season because of dilution action of the rain water. (Table,2and fig.4). (Upadhyay, 2004). Although the nitrogen quantities are higher than what was found by Shekha, (2008)who studied the same area, still it is suitable for irrigation purposes according to (WHO , 1989;Al-Radayda, 2002 andAl-Hussain ,2004) .(Table1). Biochemical oxygen demand (BOD 5 ); As table (2) and fig.(5). shows the great variations of BOD 5 records, either between the different stations or within the same station in the different seasons, which ranged between 3.5 -140 mg/l at spring in the industrial area and at summer in Runaky quarter, which may return to that the Runaky quarter containing houses discharge organic wastes continuously, as this test reflect the amount of the organic waste ( Miller,1992 ) so it obtained high variables along the year seasons, on the other hand the lower value goes to the industrial area which the area is void of houses, so the wastewater here, did not contain high amount of organic wastes this records of variable were lower than what was found by other researchers, who studied the same location, (Aziz,2006;Lak,2007 andshekha,2008)in which BOD 5 in their studies ranged between 5-208 mg/l, and it was close to what other searchers found like; Amen and Aziz,in 2005 andBapeer, in 2004, when they studied the same area, and also with, Sherif et al. When they studied Saklawyea irrigation channel in Baghdad governorate, in 1992, and what found by Rashid, et al. , in 2000 when they studied the lower part of Diyala river in the middle of Iraq. And the results were higher than what found by Rasheed in (2008) in Tanjero polluted river and other tributaries of Darbanekhan reservoir in Sulaiymania city in which never exceeded more than (8) ppm. And in almost all stations the variation between the seasons in the same station follows a rhythm that was highest value in summer, moderate in winter and the lowest in spring, in which the high value of winter returns to the high erosion of the soil and the organic wastes with it discharged into the main channel. In which any reduction or rhythm was not found between the different stations, because the main channel when it pass through the different regions within the city it gets more amounts of different types of organics carrying wastewaters; Like domestic wastes rich of organic waster ,agricultural wastes ,(point and non-Point discharge). (Cunningham & Saigo,2001). Finally we can classify the wastewater of Erbil city as week to moderate category, depending on BOD 5 values, according to Bitton classification (2005) which ranged BOD 5 between 0-220mg/l. Chemical oxygen demand(COD): Its amount were with high variation , as BOD 5, between or within the stations, the highest level recorded in station 0ne,which is the started point of the study as table,2 and fig.6 shows that, in another speech it is the fist location that gets wastewater in which it is at its richness with the organic materials and when we followed the levels we found a gradual declination in the COD amounts in which it showed the decreasing in the organic materials due to the so called self purification which oxidized different types of organics in the water. (Hynes,1960). This phenomenon found by other workers studied the area (Shekha,2008;Anber,1984;and Lak,2007).COD levels between the different seasons followed certain sequence which was; summer value> spring value > winter value, (as shown in the table), which may due to the dilution act by the water of the wintertime rain and less of the springtime rain, which act to dilute the amount of the COD gradually, which the (Mg/L) results are close of what found by Shekha, in 2008 who studied the area previously. Erbil wastewater ,can be classify as fare to moderate level ,depending on COD records, according to Bitton,(2005) category who classified the wastewater types according to COD ranges . Total suspended solid(TSS); It reflects the degree of the chemicals dissolved in the water body such as carbonate salts, and other minerals which dissolved or discharged in the water, (Cunnengham &Saigo,2001), so no wonder if we found that the content of this factor is highest throughout whole periods of the study in the station three,(spring,1000;,summer;280 and winter,96 mg/l, respectively) (table,2  which collects the waste water from the industrial area especially ,cement brick cast, mosaic, aluminum ,factories with high levels of chemicals such as carbonate salts, minerals metals....close to results found by other investigators worked in the same area, (Ganjo et al.2006;Lak,2007 andShekha, 2008). (Mg/L)