The Tala drain is the second major source of pollution along the Rosetta branch. The Tala drain receives discharge from dairy industry and agricultural drainage, as well as untreated domestic wastewater. This research involved attempting to improve water quality at the Rosetta branch by improving water quality at the Tala drain. Water quality at the Tala drain will be improved through improving effluent water quality from the dairy industry using aluminum chloride (AlCl 3) as a coagulant, with injections of carbon dioxide (CO 2), and constructing a new WWTP. Results indicated that the optimum aluminum chloride dosage was 225 mg/L at a pH value of 6.15. The estimated treatment cost of 1.0 m 3 of dairy wastewater is $0.0425 per day. The river pollutant (RP) modeling was also used to study the effect of improving water quality at the Tala drain in the Rosetta branch water quality. The RP modeling showed that applying the proposed solutions will significantly improve water quality at the Tala drain and at the Rosetta branch.
The Nile River in Egypt divides at Cairo into two branches, Damietta and Rosetta, which form the Nile delta. The Tala drain is the second major source of pollution along the Rosetta branch [
Dairy products include fresh milk, icecream, yogurts, processed milk, and cheeses. Milk and whey, the main components of waste streams, contain a high concentration of BOD (reaching up to 100,000 mg/L). Thus, any loss likely leads to a significant increase in the concentration of BOD in wastewater [
Wastewater samples were collected from the effluent of the dairy industry and analyzed for different parameters. The parameters include pH, COD, TSS, TDS, and turbidity. The concentration of contaminants must not exceed the limits specified in Egyptian Law 44/2000. The analysis of wastewater samples thus far has indicated that the concentrations of TDS, COD, and TSS exceeded the limits specified in Egyptian Law 44/2000, as shown in
This research involved attempting to improve water quality at the Rosetta branch by improving water quality at the Tala drain. Water quality at the Tala drain will be improved through improving effluent water quality from the dairy industry using aluminum chloride (AlCl3) as a coagulant, with injections of carbon dioxide (CO2), and constructing a new WWTP.
Dairy wastewater samples were collected in 10.0 liter plastic containers from the effluent of the plant. Waste
Parameter | Dairy Effluent | Law 44/2000 |
---|---|---|
COD, mg/L | 1290 | <100 |
BOD, mg/L | 600 | <60 |
TSS, mg/L | 601 | <60 |
TDS, mg/L | 2387 | <2000 |
Turbidity, NTU | 167 | <50 |
pH | 7.70 | 06 - 09 |
TOC, mg/L | 148.20 | N/A |
Clˉ, mg/L | 250 | <250 |
COD: chemical oxygen demand, BOD: biochemical oxygen demand, TOC: total organic carbon, TSS: total suspended solids, TDS: total dissolved solids, Cl−: chlorides.
water samples were placed in an ice box for transfer to the laboratory. A series of jar tests were used to evaluate the effectiveness of AlCl3 in dairy wastewater treatment. pH, is an important component for proper coagulation performance, it can affect the surface charge of floc particles and the coagulant solubility. The optimal pH values for the elimination of the turbidity, BOD, COD, and TSS ranged from 6.1 to 6.2 for the AlCl3 [
The river pollutant (RP) modeling was then used to study the effect of improving water quality at the Tala drain in the Rosetta branch water quality [
The proposed scenario is to improve water quality at the Tala drain through improving effluent water quality from the dairy industry and constructing a WWTP with a capacity of more than 200,000 m3/day (52,834,410.5 gal/day). Equal amounts of the wastewater sample were poured into a series of plastic beakers, and then each beaker was treated with 180 mg/L AlCl3. The contents were rapidly stirred at a speed of 150 rpm for 1 minute, followed by slow mixing for 10 minutes at 30 rpm. The optimum time for settling was found to be about 65 min, as shown in
Jar tests were also used to determine the optimum dosage of AlCl3. According to the above results, the following doses were selected: 120, 150, 180, 225, 250, and 300 mg/L. Results indicated that the optimum aluminum chloride dosage was 225 mg/L at a pH value of 6.15, as shown in
Water samples for analysis were collected from point sources discharging to the Tala drain. Mass balances were used to estimate the concentrations of different parameters at the Tala drain after applying the proposed solution, as shown in the equations below. Water flow and characterization at the Tala drain for the current and proposed solution, are presented in
Term | Current situation | Proposed solution (Improve water quality at the Tala drain) |
---|---|---|
Flow, m3/day | 449,878 | 449,878 |
BOD, mg/L | 89.6 | 24.8 |
COD, mg/L | 181.77 | 48.34 |
TOC, mg/L | 10 | 5.1 |
TDS, mg/L | 896.4 | 629.7 |
TSS, mg/L | 94.87 | 30.2 |
DO, mg/L | 2.23 | 2.42 |
pH, dimensionless | 7.8 | 7.9 |
COD: chemical oxygen demand, BOD: biochemical oxygen demand, TOC: total organic carbon, TSS: total suspended solids, TDS: total dissolved solids, DO: dissolved oxygen.
For COD:
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For BOD:
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For TSS:
\
For DO:
\
For TDS:
\
For TOC:
\
For Chloride:
\
For pH:
\
Cost is one of the most important parameter in wastewater treatment. A sedimentation tank and a chemical mixer tank are needed for treating wastewater by using coagulants. The treatment cost of dairy wastewater with AlCl3 and CO2 is calculated using the below equation. The cost of aluminum chloride to treat one cubic meter of dairy wastewater at pH equal 6.14 is 0.2936 EGP. The total cost to treat 20 m3 of dairy wastewater is 6.0 EGP or $0.85.
The river pollutant (RP) modeling was used to predict improvement in the Rosetta branch water quality after improving water quality at the Tala drain by constructing a WWTP with a capacity of more than 200,000 m3/day, and after improving effluent water quality from the dairy industry with the application of AlCl3 at a lower pH value. The simulations of the current situation and the proposed solution are shown in Figures 3-10. The water quality standard specified in Egyptian law 48/1982 and EPA standards for BOD is 6.0 mg/L [
The water quality standard specified in Egyptian law 48/1982 and EPA standards for COD is 10.0 mg/L [
concentration downstream of the Tala drain by about 8.77%. Applying the proposed solution will decrease the negative affect of the Tala drain in the Rosetta branch water quality. The water quality standard specified in Egyptian law 48/1982 and EPA standards for TDS is ≤500 mg/L [
solution, the pH value along the Rosetta branch is in agreement with the water quality standards specified in Egyptian and EPA standards. Consequently, the pH value in the Rosetta branch is not negatively affected by using carbon dioxide in dairy wastewater treatment.
The DO concentration specified in Egyptian law 48/1982 and EPA standards is ≥4.0 mg/L [
ceeded the 20 mg/L maximum value specified in Egyptian law 48/1982 and EPA standards [
Environmental laws have been enacted to protect public health and the environment. The company may be exposed to the risk of criminal and civil liability as a result of noncompliance with environmental regulations. Treating the dairy wastewater is very important for preventing high loading pollutants from entering and polluting the environment. The optimum time for settling was found to be 65 min. The application of 225 mg/L of AlCl3 at pH value of 6.15 caused a reduction in COD, BOD, TSS, TDS, TOC, chlorides, and turbidity of up to 84.10%, 86.60%, 87.40%, 42.30%, 50.10%, 42.0%, and 91.80%, respectively. Aluminum chloride is very effective in treating dairy wastewater, especially at pH between 6.1 and 6.2; the estimated treatment cost of treating the daily effluent (20 m3) is approximately $0.85.
The RP modeling showed that the concentrations of COD, TDS, BOD, TSS, and TOC along the Rosetta branch downstream of the Tala drain are expected to decrease after improving water quality at the Tala drain. The modeling results also showed that the proposed scenario, improving water quality at the Tala drain, will have a minor effect in reducing the chloride concentration and increasing the DO concentration. The pH is also expected to increase slightly downstream of the Tala drain after the proposed scenario is applied. In the two cases, the BOD, TSS, and DO concentrations along the study area exceeded the limit specified in the Egyptian and EPA standards; in contrast the TDS, pH, TOC, and chlorides values along the study area are within the limits specified by Egyptian and EPA standards.
This research was supported by the Department of Civil, Construction, and Environmental Engineering at the University of Alabama at Birmingham. The authors also thank the Egyptian Housing Building Research Center for their help in collecting samples and performing the chemical analyses.
Mohamed K.Mostafa, (2015) Impact of Improving Water Quality at the Tala Drain on the Rosetta Branch Water Quality. Journal of Environmental Protection,06,1149-1157. doi: 10.4236/jep.2015.610102