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Irrigation with treated wastewaters and the protection of Hennaya groundwater – Tlemcen, Algeria

Bemmoussat Abdelkader, Adjim Mohammed, Bensaoula Fouzia

Journal of Water and Land Development

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2019

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no. 43

19--27

EN

The Henaya Irrigated Perimeter (HIP) is an agricultural area irrigated by treated wastewater (TWW) of Ain El Hout treatment plant. Various analyses have shown that i) this water has low concentration of heavy metals and toxic elements, ii) the average values of the physicochemical parameters for 136 samples are satisfactory (29.2 mg O2∙dm–3 for chemical oxygen demands – COD, 13.14 mg O2∙dm–3 for biological oxygen demands – BOD, 14.2 mg∙dm–3 of suspended matter – SM, 1.82 mg∙dm–3 of N-NO3, 7.7 for pH and 927.74 μS∙cm–1 for electric conductivity – EC). Thirdly, it contains a high number of bacteria and nematodes (7200 CFU∙(100 dm3)–1 for faecal coliforms and 30 eggs∙dm–3 for intestinal Nematodes) which makes it dangerous for groundwater contamination. The objective in this work is to characterize the TWW and evaluate the impact of it use for irrigation on the quality of Hennaya groundwater. Before this, one has to prove that there is an amount of TWW that feeds the water table to show that there is a risk of pollution. We then estimated the aquifer minimum recharge value by TWW using the Thormthwaite method. The estimation has given 92 mm which is an important quantity. The results of the groundwater microbiological analyses reveal no sign of contamination. The cause is the efficiency of the degradation of pollutants of the Vadose zone. The soil purifying power Md of the HIP was evaluated by the Rehse method and gave values ranging from 2.1 to 12.7 which indicated a complete purification.

PL

Obszar nawodnień Hennaya to grunty rolnicze nawadniane oczyszczonymi ściekami z oczyszczalni Ain El Hout. W wyniku analizy stwierdzono, że w oczyszczonych ściekach stężenia metali ciężkich i substancji toksycznych jest małe, a średnie wartości parametrów fizycznych i chemicznych mierzonych w 136 próbkach są zadowalające (ChZT – 29,2 mg O2∙dm–3, BZT – 13,14 mg O2∙dm–3, zawiesina – 14,2 mg∙dm–3, N-NO3 – 1,82 mg∙dm–3, pH – 7.7 i przewodnictwo – 927,74 μS∙cm–1). Ścieki zawierają dużą liczbę bakterii coli pochodzenia kałowego (7200 jtk∙(100 dm3)–1) i jaj nicieni przewodu pokarmowego (30 jaj∙dm–3), co stanowi zagrożenie dla jakości wód gruntowych. Celem badań była analiza oczyszczonych ścieków i ocena ich wpływu na wody gruntowe nawadnianych nimi obszarów. Wstępnie należało dowieść, że ścieki zasilają wody gruntowe i istnieje ryzyko zanieczyszczenia. Za pomocą metody Thormthwaite’a oszacowano minimalne zasilanie wód podziemnych – 92 mm, czyli jest to znacząca ilość ścieków. Nie stwierdzono mikrobiologicznych zanieczyszczeń wód gruntowych. Przyczyną tego jest zdolność strefy aeracji do redukcji zanieczyszczeń. Redukcję zanieczyszczeń przez gleby nawadnianej strefy oceniano metodą Rehse, a uzyskane wartości wynoszące od 2,1 do 12,7 wskazują na całkowite oczyszczenie.

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The usage of ultrasounds to disintegrate escherichia coli bacteria contained in treated wastewater

Hawrylik Eliza

Architecture Civil Engineering Environment

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2019

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Vol. 12, no. 3

131--136

EN

Sewage and sewage sludge is a place of the occurrence of many microorganisms, including pathogenic and relatively pathogenic bacteria. They may reach other environments, e.g. receiver waters or soil, thus creating a biological threat. The aim of this paper was to study, in laboratory conditions, the effect of low-frequency ultrasound on the disintegration of Escherichia coli bacteria present in purified wastewater. E. coli bacilli and ultrapure water were used for the study. The samples were exposed to ultrasounds at 20 and 40 kHz for variable time of sonication and at two different modes of the ultrasonic cleaner operation: continuous and pulsed. Studies have shown that ultrasound has an effective impact on E. coli bacilli. Already the 3-minute interaction of ultrasounds at 20 kHz with the pulsation mode of impact of the device caused a decrease in the number of these bacteria by over 90%. The 20-minute operation of 40 kHz ultrasound waves resulted in a decrease in the amount of bacteria by nearly 70% compared to the control. The obtained results, therefore, indicate the possibility of using the disintegration process of low frequency ultrasounds for removing Escherichia coli bacteria present in treated wastewater.

3

Uptake of Toxic Trace Metals (Cd, Pb) and Micro Nutrients (Cu, Zn, Mn) by Sugarcane (Saccharum Officinarum L.) Irrigated with Treated Effluents of Sugar Industry

Damodharan U., Reddy M. V.

Archives of Environmental Protection

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2014

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Vol. 40, no. 1

13--22

EN

The accumulation and translocation of trace metals in soil and in sugarcane crop irrigated with treated effluents from sugar industry compared to soil and sugarcane crop irrigated with bore-well water were determined. In the present study the impact of irrigation with treated effluent from the sugar industry on the trace metal contamination of sugarcane juice was assessed. It revealed that the mean concentrations of Cd, Pb, Cu, Mn and Zn in the soil of fields irrigated with effluent and in juice from sugarcane grown on such fields were higher than those from bore-well water irrigated fields. The concentrations of trace metals in treated effluent exceeded the permissible limits of the Indian standards (Central Pollution Control Board-2000). The concentrations of Cd, Pb, Cu and Zn in juice of sugarcane grown on fields irrigated with effluent also exceeded the permissible limits of Indian standards and WHO/FAO expert committee recommendations. Their concentrations in juice of sugarcane grown in fields irrigated with bore-well water were within the limits of safety, except for Cd. The transfer factor for Zn was considerably higher than those of the other trace metals. The metal concentrations of sugarcane juice showed significant correlations with those of soil, which was not the case when bore well water was used for irrigation.