Simulation of wastewater dispersion of recycling scrap paper from Muc Son Paper factory to the downstream Chu river

This research simulates and forecasts the area as well as the level of pollution dispersion of Muc Son Paper Factory’s wastewater to the downstream of Chu River under two scenarios: Scenario 1 - wastewater treatment system is broken; treatment efficiency is equal to 0; Scenario 2 - wastewater treatment system is working with its designed capacity. The applied results of the MIKE 11 model show that: the impacted area from the plant’s discharge is 0.2 km upstream and 2 km downstream of the confluence point. The simulation results under Scenario 1 show TSS, BOD5 and COD contents being 18.3–35.7 mg/L, 8.3–17.2 mg/L and 12.2–23.7 mg/L, respectively, negatively affect the water environment downstream of Chu river. The results are then compared with measured data to confirm the reliability of the model. This research is a scientific and practical basis for the Muc Son Paper factory to operate the wastewater treatment system and manage the water quality output to ensure environmental regulations.

A STUDY ON IMPACT OF CLIMATE CHANGE TO SALINITY AT WATER INTAKE POINTS OF SUPPLY WATER FACTORIES AND ADAPTATION SOLUTIONS PROPOSAL

The paper presents a research on impact of climate change to salinity at water intake points of supply water factories and proposes adapting solution. In the research, the change precipitation induced flow as well as the change of discharge of reservoirs flow according to climate change scenarios are calculated by NAM and regulation of reservoirs models. These flows will be upstream boundary data for Mike 11 model to simulate salinity intrusion on the whole system, and sea level rise condition will be the downstream boundary data. After calculating salinity change at water intake points, solutions will be proposed based on simulation results as well as supply water planning under climate change condition.

IMPACTS OF CLIMATE CHANGE AND SEA LEVEL RISE ON SALINITY INTRUSION IN THE LOWER DONG NAI RIVER SYSTEM

Ho Chi Minh City (HCMC) is ranked among the top 10 cities in the world most likely to be severely affected by climate change and sea level rise (SLR). This study was to assess the impacts of change of upstream flow and sea level rise due to climate change on salinity intrusion in HCMC. The MIKE 11 model with modules hydrodynamic (HD) and advection-dispersion (AD) was applied to this problem by setting up the whole lower Dong Nai river system. Based upon the observed water level and salinity concentration data in 2009, the calibration and validation results indicated that the MIKE11 model was able to simulate the streamflow and salinity concentration with NSE values exceeding 0.6 for both calibration and validation periods. As a result, the differences in salinity concentration under climate change and SLR scenarios were analyzed. The simulated results illustrate that the saltwater will move inland in the future, especially in the dry season.

Simulation of organic carbon loading using MIKE 11 model: a case of River Nzoia, Kenya

River Nzoia is the largest river draining into the Kenyan portion of Lake Victoria. This river receives both point sources of pollution from industrial and municipal wastes, and non-point sources from agricultural runoff in the catchment. The objective of this study was to simulate dissolved oxygen (DO) and biochemical oxygen demand (BOD) of the middle section of River Nzoia using MIKE 11 model. The model was calibrated using discharge and water quality data for 2009 and validated with March–April 2013 data. The model performance was good with coefficient of determination (R2) values of between 0.845 and 0.995, Nash–Sutcliffe efficiency values of between 0.748 and 0.993 and percent bias of less than 10 for both calibration and validation of electrical conductivity (EC), DO and BOD. EC and BOD values were lower for April compared to March which could be attributed to dilution during high flows. DO values were above the recommended minimum level of 4 mg/l in all the sections of the river in the wet period but some sections had lower than 4 mg/l during low flow period. The government agencies such as Water Resources Management Authority and National Environment Management Authority should enforce the effluent standards to ensure that industries and wastewater treatment plants adhere to the maximum allowable limit for BOD and also improve their treatment efficiencies of wastewater plants so as to improve the quality of River Nzoia which is important in the overall management of the Lake Victoria basin.