Evaluation and comparison of centralized drinking water softening technologies: Effects on water quality indicators

Trends toward closure of white water recirculation loops in papermaking often lead to a need for system modifications. We conducted a pilot-scale study using pulsed electrocoagulation technology to treat the effluent of an old corrugated containerboard (OCC)-based paper mill in order to evaluate its treatment performance. The operating variables were a current density of 0–240 A/m2, a hydraulic retention time (HRT) of 8–16 min, and a coagulant (anionic polyacrylamide) dosage of 0–22 mg/L. Water quality indicators investigated were electrical con-ductivity, suspended solids (SS), chemical oxygen demand (COD), and true color. The results were encouraging. Under the operating conditions without coagulant addition, the highest removals for conductivity, SS, COD, and true color were 39.8%, 85.7%, 70.5%, and 97.1%, respectively (with an HRT of 16 min). The use of a coagulant enhanced the removal of both conductivity and COD. With an optimal dosage of 20 mg/L and a shortened HRT of 10 min, the highest removal achieved for the four water quality indicators were 37.7%, 88.7%, 74.2%, and 91.7%, respectively. The water qualities thus attained should be adequate to allow reuse of a substantial portion of the treated effluent as process water makeup in papermaking.

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MONITORING OF WATER QUALITY INDICATORS FOR IMPROVING WATER RESOURCES MANAGEMENT OF BAHLUI RIVER

Environmental Engineering and Management Journal ◽

10.30638/eemj.2011.048 ◽

2011 ◽

Vol 10 (3) ◽

pp. 327-332

Author(s):

Igor Cretescu ◽

Roxana Elena Benchea ◽

Matei Macoveanu

Keyword(s):

Water Quality ◽

Water Resources ◽

Quality Indicators ◽

Water Resources Management ◽

Water Quality Indicators ◽

Resources Management

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Spatio-temporal Variations in Water Quality Parameter Trends in River Waters

Revista de Chimie ◽

10.37358/rc.18.10.6659 ◽

2018 ◽

Vol 69 (10) ◽

pp. 2940-2952 ◽

Cited By ~ 1

Author(s):

Martina Zelenakova ◽

Pavol Purcz ◽

Radu Daniel Pintilii ◽

Peter Blistan ◽

Petr Hlustik ◽

...

Keyword(s):

Water Quality ◽

Chemical Oxygen Demand ◽

Quality Indicators ◽

Water Resource Management ◽

Oxygen Demand ◽

Temporal Variations ◽

Water Quality Parameter ◽

Agricultural Activity ◽

Water Quality Indicators ◽

Nitrite Nitrogen

Evaluating trends in water quality indicators is a crucial issue in integrated water resource management in any country. In this study eight chemical and physical water quality indicators were analysed in seven river profiles in the River Laborec in eastern Slovakia. The analysed water quality parameters were biochemical oxygen demand (BOD5), chemical oxygen demand (CODCr), pH, temperature (t), ammonium nitrogen (NH4+-N), nitrite nitrogen (NO2--N), nitrate nitrogen (NO3--N), and total phosphorus (TP). Data from the monitored indicators were provided by the Ko�ice branch of the Slovakian Water Management Company, over a period of 15 years from 1999 to 2013. Mann�Kendall non-parametric statistical test was used for the trend analysis. Biochemical and chemical oxygen demand, ammonium and nitrite nitrogen content exhibit decreasing trends in the River Laborec. Decreasing agricultural activity in the area has had a significant impact on the trends in these parameters. However, NO2--N was the significant parameter of water quality because it mostly exceeds the limit value set in Slovak legislation, Regulation No. 269/2010 Coll. In addition, water temperature revealed an increasing trend which could be caused by global increase in air temperature. These results indicate that human activity significantly impacts the water quality.

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Assessment of Automatically Monitored Water Levels and Water Quality Indicators in Rivers with Different Hydromorphological Conditions and Pollution Levels in Greece

Hydrology ◽

10.3390/hydrology8020086 ◽

2021 ◽

Vol 8 (2) ◽

pp. 86

Author(s):

Angeliki Mentzafou ◽

George Varlas ◽

Anastasios Papadopoulos ◽

Georgios Poulis ◽

Elias Dimitriou

Keyword(s):

Water Quality ◽

Time Series ◽

Quality Indicators ◽

High Frequency ◽

Automatic Monitoring ◽

Water Levels ◽

High Temporal Resolution ◽

Water Quality Indicators ◽

Pollution Levels ◽

Riverine Ecosystems

Water resources, especially riverine ecosystems, are globally under qualitative and quantitative degradation due to human-imposed pressures. High-temporal-resolution data obtained from automatic stations can provide insights into the processes that link catchment hydrology and streamwater chemistry. The scope of this paper was to investigate the statistical behavior of high-frequency measurements at sites with known hydromorphological and pollution pressures. For this purpose, hourly time series of water levels and key water quality indicators (temperature, electric conductivity, and dissolved oxygen concentrations) collected from four automatic monitoring stations under different hydromorphological conditions and pollution pressures were statistically elaborated. Based on the results, the hydromorphological conditions and pollution pressures of each station were confirmed to be reflected in the results of the statistical analysis performed. It was proven that the comparative use of the statistics and patterns of the water level and quality high-frequency time series could be used in the interpretation of the current site status as well as allowing the detection of possible changes. This approach can be used as a tool for the definition of thresholds, and will contribute to the design of management and restoration measures for the most impacted areas.

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