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1

Characteristics of natural organic matter removed from water along with its treatment

Urbanowska A., Kabsch-Korbutowicz M.

Environment Protection Engineering

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2016

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Vol. 42, nr 2

183--195

EN

The object of this study was to examine the nature of natural organic matter (NOM) removed on each stage of water treatment train used in the “Mokry Dwór” Wrocław Water Treatment Plant (WTP) and to compare obtained results with water treatment efficiencies achieved with the use of membrane ultrafiltration, ion-exchange and UF/ion-exchange integrated processes. In the experiments fractional analysis with the use of polymeric resins (DAX-8, XAD-4 and IRA-958) was used. Obtained results have shown that most (56%) of the raw water NOM was found in fraction characterized by presence of humic and fulvic acids (VHA and SHA fractions). VHA fraction made the most of DOC removed in examined water treatment train and coagulation was mainly responsible for this effect. Integrated process consisting of MIEX®DOC ion exchange and PES 10 kDa ultrafiltration turned out to be very effective at high molecular weight hydrophobic compounds removal from water being much less efficient with hydrophilic compounds.

2

Effect of polyaluminium chlorides overdosage on effectiveness of coagulation and filtration

Gumińska J., Kłos M.

Environment Protection Engineering

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2015

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Vol. 41, nr 1

5--14

EN

PACls overdosage has negative impact on the operation and the effectiveness of coagulation and separation of post-coagulation suspensions. The results of the pilot study revealed that a sharp increase of fine particles was observed at reaching and exceeding the isoelectric point. Based on the full-scale research with PACl_1 (B = 2, 4) it was stated that these particles did not cause deterioration of standard quality parameters (turbidity, absorbance UV254, colour, TOC, CODMn) of water purified in conventional treatment. However, the particles not retained in sedimentation tanks supplied rapid filters and caused their overloading, and hence shortening of filtration cycles.

3

Efficiency of ozonation followed by filtration through a biologically active adsorption bed at removing biogenic organic substances from surface water

Świderska-Bróż M, Wolska M.

Environment Protection Engineering

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2012

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Vol. 38, nr 2

19--28

EN

Water entering the plant varies significantly in the content of total organic carbon and its fractions. The treatment train includes coagulation, sedimentation, rapid sand filtration, ozonation, biofiltration, disinfection and alkalization. The study aimed at assessing the applicability of ozonation, followed by biological filtration, to remove organic substances from surface water. Upon coagulation, sand filtration, ozonation, adsorption onto a biological activated carbon filter (BAF), and disinfection with chlorine and chlorine dioxide, water samples differed considerably in organic matter content before ozonation, as well as before and after biofiltration. The ozonation process brought about a reduction in total organic carbon and dissolved organic carbon concentrations, which was concomitant with a significant increase in the concentrations of biodegradable dissolved organic carbon fractions and in assimilable organic carbon. This may be attributed to the transformation of non-biodegradable substances to lower molecular weight compounds that are easier to assimilate by the microorganisms normally colonizing an adsorption bed. Even though the substances that originated from the ozonation process were effectively removed during biofiltration, the extent of removal was still insufficiently high to provide desired biological stability of the water. A benefit of biofiltration was efficient removal of refractory substances as a result of adsorption. The efficiency of the ozonation and biofiltration processes at removing organic substances increased in proportion with the increase in their concentrations in the water being treated.

4

Analysis of post-coagulation properties of flocs in terms of coagulant choice

Gumińska J., Kłos M.

Environment Protection Engineering

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2012

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Vol. 38, nr 1

103-114

EN

The knowledge of properties of floes produced in coagulation may enable one to reduce effects of their breakage in a treatment system. This is particularly important in treatment of water contaminated mainly with natural organic matter; produced floes are fragile and susceptible to rupture. The purpose of the research was to determine the influence of a coagulant type on postcoagulation suspension strength. The results show that floes produced based on prehydrolyzed coagulants are more resistant to breakage than those produced by a hydrolyzing coagulant. Strength of post-coagulation suspension increased with the increase of polynuclear Al species (Alb species).

5

Preliminary research into the digestion of post-coagulation sludge

Płonka I., Barbusiński K.

Environment Protection Engineering

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2010

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Vol. 36, nr 3

59-67

EN

An increasingly higher number of water treatment plants are currently searching for a technology which would make it possible to dispose post-coagulation sludge from water treatment processes. Due to the fact that sludge contains a substantial amount of organic compounds, some tests were conducted to see how such sludge can be stabilised in anaerobic conditions. Sludge supplied by two water treatment plants was tested. Sludge 1 was a mixture of sludge from the treatment of filter backwash water and backwash water separated from water after coagulation. Sludge 2 was the product of the treatment of backwash water from carbon and contact filters as well as wastewater produced when primary settling tanks are cleaned. Prior to digestion, post-coagulation sludge was inoculated with the sewage sludge collected from the anaerobic digester of a municipal wastewater treatment plant. To determine the effectiveness of the tests, the sewage sludge used as an inoculate was also digested. The digestion process was conducted for 35 days at a temperature of 37 °C. Compared to sewage sludge, a small amount of the sludge-digestion gas produced by the post-coagulation sludge was observed during the process. For the sewage sludge, the sludge-digestion gas evolution rate per volatile solids (VS) input was 0.19 m3/kg VS, for post-coagulation sludge 1-0.09 m3/kg VS and for post-coagulation sludge 2-0.05 m3/kg VS. The sludge mineralization rate expressed as a percentage loss of dry volatile solids was the highest for the sewage sludge alone and it was 19%, whereas for the post-coagulation sludge it was 11.8% (sludge 1) and 5.8% (sludge 2). The digestion process substantially enhanced the filtration properties of the tested sludge. The post-coagulation sludge produced small volumes of sludge digestion gas, thus it can be stated that the digestion of this sludge alone would not be technically nor economically profitable. Therefore, research into the digestion of post-coagulation sludge with a considerably higher share of sewage sludge should be done to identify the potential for their costabilization. Such a solution would provide a potential opportunity for resolving the problem of post-coagulation sludge through its disposal in wastewater treatment plants.

6

Improvement of atypical ground water conditioning processes

Puszkarewicz A., Kaleta J., Piech A.

Environment Protection Engineering

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2009

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Vol. 35, nr 4

41-48

EN

Laboratory research into the treatment technology of ground water from the Huta Komorowska water intake was carried out. The water is drawn for drinking purposes. The results of research were used in order to improve water conditioning technology for the existing water treatment plant. This new technology is based on two stages of filtration. A water to be treated contains various forms of iron which forms chelates with humus compounds. They have to be removed in a contact coagulation process. In the first stage of filtration, raw water was passed through a triplex filter consisting of aquacleanit - support layer, quartz sand - proper layer and anthracite - surface layer. Coagulant SAX-18 (sodium aluminate) at the dose of 2 mg Al/dm3 proved to be most effective in reducing colour intensity, turbidity, iron content, oxygen demand and absorbance. It also increased pH, hence the water alkalinity, which made it less aggressive. In the frame of the second filtration stage, the filter with chemical active mass (Defeman) was used. The water in the first and second stages was filtered at the rate of 7.5 m/h.