Electrochemical treatment of wastewater from the process of surface protection of metals

U radu je ispitana mogućnost primjene elektrokemijskih metoda (elektroredukcije, elektrokoagulacije, indirektne anodne oksidacije) korištenjem željezovog i aluminijevog seta elektroda sa ili bez dodatka elektrolita za obradu otpadne vode koja nastaje u procesu površinske zaštite metala. Otpadna voda je karakterizirana visokim vrijednostima cinka (2029 mg dm-3) i željeza (78,4 mg dm-3) te povišenim vrijednostima Cr(VI) (5,4 mg dm-3) i kemijske potrošnje kisika (820 mg dm-3) koje premašuju granične vrijednosti za ispust u okoliš za 1014, 39, 56, odnosno 6,6 puta. U svrhu optimizacije procesa u radu je ispitan utjecaj vrste elektroda (željezo, aluminij), kontaktnog vremena (5-30 minuta), mase elektrolita (0,5-1,5 g NaCl) te jakosti struje (20-50 A) na stupanj uklanjanja navedena četiri pokazatelja. Između dvije testirane elektrode, željezova se pokazala značajno efikasnijom u uklanjanju svih mjerenih pokazatelja, a naročito Cr(VI) i KPK. Statistički značajno bolji rezultati u uklanjanju KPK za obje elektrode su postignuti dodatkom elektrolita te porastom jakosti struje s 20 na 40 A. Najveći udio anorganskog onečišćenja se ukloni u prvih 5 minuta obrade. Najbolji rezultati su postignuti kombinacijom dviju elektroda uz dodatak klorida kao elektrolita. Nakon 15 minuta elektroredukcije/elektrokoagulacije/indirektne anodne oksidacije pomoću željezovih elektroda, 15 minuta elektrokoagulacije pomoću aluminijevih elektroda te 20 minuta koagulacije/flokulacije i oksidacije zrakom uklonjeno je 99,79% Cr(VI), 99,97% Fe, 98,23% Ni, 99,23% Cu, 99,999% Zn, 98,00% Pb i 86,46% KPK a svi mjereni pokazatelji su zadovoljavali uvjete za ispust u okoliš, dok su se izlazne koncentracije teških metala kretale od 0,009 do 0,023 mg dm-3.The paper investigated a possibility of implementing electrochemical methods (electroreduction, electrocoagulation, indirect anodic oxidation) by using iron and aluminium electrode sets, with or without the addition of electrolytes for treatment of wastewater generated in the process of surface protection of metals. The wastewater is characterized by high values of zinc (2029 mg dm-3) and iron (78.4 mg dm-3) as well as increased values of Cr(VI) (5.4 mg dm-3) and chemical oxygen demand (820 mg dm-3) that exceed limit values for discharge into the environment by 1014, 39, 56 and 6.6 times, respectively. In order to optimize the process, the paper investigated the impact of electrode type (iron, aluminium), contact time (5-30 minutes), electrolyte mass (0.5-1.5 g NaCl) and amperage (20-50 A) on the removal level of the stated four indicators. Of the two tested electrode types, iron electrodes proved to be significantly more efficient in the removal of all measured indicators, in particular Cr(VI) and COD. A statistically significant improvement of the results in COD removal for both electrode types was achieved by the addition of electrolytes and increased amperage from 20 to 40 A. The majority of inorganic pollution is removed in the first 5 minutes of treatment. The best results are achieved by a combination of the two electrode types, with the addition of chloride as an electrolyte. After 15 minutes of electroreduction / electrocoagulation / indirect anodic oxidation by iron electrodes, 15 minutes of electrocoagulation by aluminium electrodes and 20 minutes of coagulation / flocculation and oxidation by air, 99.79% Cr(VI), 99.97% Fe, 98.23% Ni, 99.23% Cu, 99.999% Zn, 98.00% Pb and 86.46% COD were removed. All measured indicators complied with the conditions for discharge into the environment whereas all output concentrations of heavy metals ranged from 0.009 to 0.023 mg dm-3

Thermal/electrochemical processing of slaughterhouse wastewater

U radu je prikazana obrada klaoničkih otpadnih voda kombinacijom termičke predobrade i glavne elektrokemijske obrade uz simultano ozoniranje. Ispitana je učinkovitost uklanjanja karakterističnih pokazatelja te količina generiranog mulja obzirom na vrstu elektroda (nehrđajući čelik, željezo, aluminij), vrijeme obrade (5-30 minuta) i jakost struje (50-100 A). Otpadna voda je karakterizirana vrlo neugodnim mirisom, visokim vrijednostima boje (17400 CoPt), mutnoće (4230 NTU) ukupne suspendirane tvari (1730 mg dm-3), kemijske potrošnje kisika (3720 mg dm-3) te biokemijske potrošnje kisika (1870 mg dm-3) te povišenim vrijednostima amonija (128 mg dm-3) i fosfata (93 mg dm-3). Termičkom predobradom je uklonjeno 98,23% mutnoće, 89,94% boje, 75,14% ukupne suspendirane tvari (UST), 49,73% BPK5 i 36,29% KPK. Set elektroda od nehrđajućeg čelika se pokazao najučinkovitijim u uklanjanju organskih pokazatelja i amonija, a rezultirao je i najmanjim volumenom otpadnog mulja, dok su aluminijeve elektrode najučinkovitije u uklanjanju boje, ali uz najveću produkciju mulja. Najbolji rezultati su dobiveni kombinacijom sve tri vrste elektroda uz istovremeno ozoniranje uz kontaktno vrijeme 20 minuta, jakost struje od 70 A i napon od 10 V. Nakon elektrokoagulacije/elektroksidacije pomoću elektroda od nehrđajućeg čelika, elektrokoagulacije/ozoniranja pomoću željezovih elektroda, elektrokoagulacije/ozoniranja pomoću aluminijevih elektroda te završnog ozoniranja uklonjeno je 100% boje, mutnoće i UST, 99,77% KPK te 99,25% BPK5, 99,98% fosfata, 99,80% amonija i 43,86% ukupne otopljene tvari, a svi mjereni pokazatelji su zadovoljavali uvjete za ispust u okoliš.The paper presents slaughterhouse wastewater treatment implemented as a combination of thermal pre-treatment and main electrochemical treatment, with a simultaneous ozonation. The efficiency of the characteristic indicator removal and the quantity of generated sludge according to electrode types (stainless steel, iron and aluminium), treatment time (5-30 minutes) and amperage (50-100 A) was tested. The wastewater is characterized by a very unpleasant odour, high colouring value (17400 CoPt), turbidity (4230 NTU), total suspended solids (1730 mg dm-3), chemical oxygen demand (3720 mg dm-3) and biochemical oxygen demand (1870 mg dm-3) as well as increased values of ammonium (128 mg dm-3) and phosphates (93 mg dm-3). Thermal pre-treatment removed 98.23% turbidity, 89.94% colour, 75.14% total suspended solids (TSS), 49.73% BOD5 and 36.29% COD. A stainless steel electrode set proved to be the most efficient in the removal of organic indicators and ammonium and the lowest sludge volume, whereas aluminium electrodes were the most efficient in colour removal, although with the highest sludge production. The best results were achieved by a combination of all three electrode types, with a simultaneous ozonation of 20-minute contact time, amperage of 70 A and voltage of 10 V. Following the electrocoagulation / electrooxidation by stainless steel electrodes, electrocoagulation / ozonation by iron electrodes and electrocoagulation / ozonation with aluminium electrodes and the final ozonation, 100% colour, turbidity and TSS were removed as well as 99.77% COD and 99.25% BOD5, 99.98% phosphates, 99.80% ammonium and 43.86% total dissolved solids. All measured indicators complied with the conditions for discharge into the environment

Treatment of Acidic Mine Effluents and Wastewater from Ship Cleaning Facilities by Application of Red Mud

U radu je prikazan postupak obrade kiselog efluenta nastalog u toku eksploatacije i prerade bakrene rude kompleksa Borskih rudnika (Bor- Krivelj-Cerovo) pomoću crvenog mulja - otpadnog produkta iz procesa proizvodnje glinice u bivšoj tvornici glinice iz Obrovca te primjena nastalog otpadnog mulja za pročišćavanje otpadnih voda iz prališta brodova. Izvršena je karakterizacija otpadnih voda i crvenog mulja te su utvrđeni optimalni uvjeti uklanjanja ključnih pokazatelja iz otpadnih voda. Rudnička otpadna voda je karakterizirana niskom pH vrijednošću (3,21), visokom koncentracijom sulfata (10830 mg dm-3), visokim vrijednostima željeza (921 mg dm-3), mangana (107 mg dm-3), bakra (92 mg dm-3) i cinka (59 mg dm-3), dok su u otpadnoj vodi iz prališta brodova ključna onečišćivala bakar (34 mg dm-3), cink (59 mg dm-3) i boja (11470 PtCo). Obzirom na visok neutralizacijski i sorpcijski kapacitet crvenog mulja, njegovo miješanje s rudničkom otpadnom vodom u optimalnim omjerima dovodi do neutralizacije oba otpadna produkta te uklanjanja teških metala iz otpadne vode ispod graničnih vrijednosti. Pri optimalnim uvjetima uklanjanja (pH = 8; kontaktno vrijeme = 15 minuta) uklonjeno je više od 99,9% Cr, Mn, Fe, Cu i Zn te 65,5% sulfata. Preostali otpadni mulj je moguće ponovo upotrijebiti za pročišćavanje otpadnih voda iz prališta brodova visoko opterećenih bojama protiv obraštaja, a s jednom dozom mulja je moguće izvršiti pet ciklusa pročišćavanja s učinkovitošću uklanjanja ključnih pokazatelja preko 99%.The paper presents a procedure for treating acidic effluent generated during the exploitation and proce¬ssing of copper ore at the Bor mining complex (Bor-Krivelj-Cerovo) by application of red mud, a waste by-product of the alumina production process at the now-defunct alumina plant in Obrovac, and the application of the generated waste mud to treating wastewater from ship cleaning facilities. The characterisation of wastewater and red mud was carried out, resulting in the determination of optimal conditions for the removal of key indicators from wastewater. The acidic mine wastewater is characterised by a low pH value (3.21), high sulfate concentration (10,830 mg dm-3), high values of iron (921 mg dm-3), manganese (107 mg dm-3), copper (92 mg dm-3) and zinc (59 mg dm-3), whereas the key polluters in the wastewater from ship cleaning facilities include copper (34 mg dm-3), zinc (59 mg dm-3) and paint (11470 PtCo). Considering a high neutralisation and adsorption capacity of red mud, its mixing with mine drainage wastewater in op¬timal ratios leads to the neutralisation of both waste by-products and the removal of heavy metals from wastewater to below their limit values. Under the optimal removal conditions (pH = 8; contact time = 15 minutes), more than 99.9% of Cr, Mn, Fe, Cu and Zn as well as 65.5% of sulfates were removed. The remaining waste mud can be reused in the treatment of wastewater from ship cleaning facilities which has a high load of anti-fouling paint. A single mud dosage is sufficient for five treatment cycles and has a key indicator removal efficiency rate of over 99%

Electrochemical treatment of wastewater from potato chips production

U radu je prikazan novi kombinirani pristup u obradi otpadne vode koja nastaje u procesu prerade krumpira u čips kombinacijom elektrokemijskih metoda i ozoniranja. Otpadna voda je karakterizirana visokim vrijednostima ukupne suspendirane tvari (1517 mg dm-3), kemijske potrošnje kisika (2240 mg dm-3) te biokemijske potrošnje kisika (1780 mg dm-3) koje premašuju granične vrijednosti za ispust u okoliš za 43, 18 odnosno 71 puta. U svrhu optimizacije procesa u radu je ispitan utjecaj vrste elektroda (nehrđajući čelik, željezo, aluminij), kontaktnog vremena (5-30 minuta) te jakosti struje (30-100 A) na stupanj uklanjanja navedena tri parametra. Iako se aluminijev set elektroda pokazao najefikasnijim za uklanjanje navedenih pokazatelja, značajno bolji rezultati su dobiveni kombinacijom sve tri vrste elektroda uz istovremeno ozoniranje. Nakon 10 minuta elektrokoagulacije/elektroksidacije pomoću elektroda od nehrđajućeg čelika, 5 minuta elektrokoagulacije/ozoniranja pomoću željezovih elektroda, 15 elektrokoagulacije/ozoniranja pomoću aluminijevih elektroda te 15 minuta ozoniranja uklonjeno je 100% boje, mutnoće i UST, 94,5% KPK te 98,9% BPK5 a svi mjereni pokazatelji su zadovoljavali uvjete za ispust u okoliš.The paper presents a new approach which combines electrochemical methods and ozonation to wastewater treatment from potato processing in potato chips production. This wastewater is characterized by high values of total suspended solids (1517 mg dm-3), chemical oxygen demand (2240 mg dm-3) and biochemical oxygen demand (1780 mg dm-3) that exceed the limit values for discharges into the environment by 43.18 and 71 times, respectively. For the purpose of optimisation of this process, the paper investigated the impact of different electrode types (stainless steel, iron, aluminium), contact time (5-30 minutes) and amperage (30-100 A) on the degree of removal of these three parameters. Although the aluminium electrode set proved the most effective for the removal of these indicators, significantly better results were obtained by a combination of all three electrode types with simultaneous ozonation. After 10 minutes of electrocoagulation / electrooxidation with stainless steel electrodes, 5 minutes of electrocoagulation / ozonation with iron electrodes, 15 minutes of electrocoagulation / ozonation with aluminium electrodes and 15 minutes of ozonation, 100% colour, turbidity and TSS, 94.5% COD and 98. 9% BOD5 were removed, and all measured indicators met the requirements for discharges into the environment

Detoxification of wastewater from the wine-making process by means of chemical/electrochemical methods

U radu je praćena detoksifikacija otpadne vode od prerade grožđa kroz različite faze kemijske i elektrokemijske obrade. U cilju uklanjanja organskih/anorganskih onečišćivala iz otpadne vode korištena je oksidacija ozonom i taloženje pomoću CaO kao faza predobrade te tri elektrokemijske metode (elektrooksidacija, elektroredukcija i elektrokoagulacija) korištenjem elektroda od nehrđajućeg čelika, željeza i aluminija uz istovremeno ozoniranje u svrhu glavne obrade. Toksični učinak otpadne vode prije i nakon svake od faza pročišćavanja praćen je preko vrijednosti parametara klijavosti nakon izlaganja biljke Hordeum vulgare L. uzorcima nepročišćene/pročišćene otpadne vode. Otpadna voda je okarakterizirana niskom pH vrijednošću (4,02), intenzivnim mirisom i obojenjem (28400 PtCo), visokim vrijednostima organskih pokazatelja (18430 mg dm-3 KPK, 1340 mg dm-3 ukupnih fenola, 1720 mg dm-3 BPK5) te povišenim vrijednostima hranjivih soli i teških metala. Sinergijski i aditivni učinak između organskih pokazatelja, prvenstveno fenola i teških metala te niska pH vrijednost su vjerojatno odgovorni za izuzetno visok fitotoksični učinak s EC50 vrijednošću od svega 0,08 % te potpunim zastojem klijavosti nakon izlaganja sjemena nerazrijeđenoj otpadnoj vodi. Predobrada vapnom pri kojoj je uklonjeno između 46% i 99,8% teških metala, 90,4 % boje, 98,3 % mutnoće, 98,6 % UST, 95,4 % fosfata, 91,5 % sulfata te između 39 % i 47 % organskih pokazatelja je rezultirala 50 %-tnim smanjenjem toksičnog učinka. Završnom obradom dobiven je bistar efluent bez mirisa i s jedva primijetim obojenjem sa stupnjem uklanjanja karakterističnih pokazatelja između 73,8 % i 100 %, čime je u potpunosti uklonjen i njegov toksični učinak (Klijavost = 99,2±0,2 %; Indeks klijavosti = 99,2±0,2 %). Iz navedenog je moguće zaključiti da je odabrani set metoda pogodan za detoksifikaciju biološki slabo razgradljivih efluenata vrlo složenog i varijabilnog sastava kao što su vinarijske otpadne vode. Utvrđivanje parametara klijavosti na biljci Hordeum vulgare L. se pokazalo kao vrlo osjetljiv, jednostavan i jeftin test sustav za praćenje toksičnog učinka industrijskih efluenata te praćenje stupnja njihove detoksifikacije u toku različitih faza i metoda obrade.The paper monitors detoxification of wastewater from the processing of grapes through various phases of chemical and electrochemical treatment. For the purpose of removing organic / inorganic pollutants from wastewater, oxidation with ozone and sedimentation with CaO were used as preliminary treatment phases as well as three electrochemical methods (electro-oxidation, electro-reduction and electro-coagulation) utilizing electrodes made of stainless steel, iron an aluminium, with a simultaneous ozonation as the primary treatment. The toxic effect of wastewater before and after each treatment phase was monitored through the values of the germination parameter after exposure of the plant Hordeum vulgare L. to the samples of untreated/treated wastewater. The wastewater was characterized by low pH value (4.02), intense odour and colouring (28400 PtCo), high values of organic pollutants (18430 mg dm-3 COD, 1340 mg dm-3 total phenols, 1720 mg dm-3 BOD5) and elevated values of nutrients and heavy metals. The synergic and additive impact among organic indicators, primarily phenols and heavy metals and a low pH value, were probably responsible for an extremely high phytotoxic impact with the EC50 value of only 0.08 % and a full cessation of the germination after the seed exposure to undiluted wastewater. A preliminary treatment with lime, which removed 46% - 99.8% of heavy metals, 90.4 % of colour, 98,3 % of turbidity, 98.6 % total suspended solids, 95,4 % of phosphates, 91.5 % of sulphates and 39 % - 47 % of organic indicators, resulted in 50 % toxic impact reduction. The final treatment resulted in clear effluent without odour and a barely noticeable colouring, with a removal degree of characteristic indicators from 73.8 % to 100 %, which also fully removed its toxic impact (germination = 99.2±0.2 %; germination index = 99.2±0.2 %). Based on the above stated, it can be concluded that the selected set of methods is suitable for detoxification of biologically poorly degradable effluents of a very complex and variable composition, such as wastewater from the wine-making process. The determination of the germination parameters on the plant Hordeum vulgare L. proved to be a very sensitive, simple and inexpensive test system for monitoring the toxic impact of industrial effluents and the degree of their detoxification in different treatment phases and with different methods

Electrochemical treatment of wastewater from potato chips production

U radu je prikazan novi kombinirani pristup u obradi otpadne vode koja nastaje u procesu prerade krumpira u čips kombinacijom elektrokemijskih metoda i ozoniranja. Otpadna voda je karakterizirana visokim vrijednostima ukupne suspendirane tvari (1517 mg dm-3), kemijske potrošnje kisika (2240 mg dm-3) te biokemijske potrošnje kisika (1780 mg dm-3) koje premašuju granične vrijednosti za ispust u okoliš za 43, 18 odnosno 71 puta. U svrhu optimizacije procesa u radu je ispitan utjecaj vrste elektroda (nehrđajući čelik, željezo, aluminij), kontaktnog vremena (5-30 minuta) te jakosti struje (30-100 A) na stupanj uklanjanja navedena tri parametra. Iako se aluminijev set elektroda pokazao najefikasnijim za uklanjanje navedenih pokazatelja, značajno bolji rezultati su dobiveni kombinacijom sve tri vrste elektroda uz istovremeno ozoniranje. Nakon 10 minuta elektrokoagulacije/elektroksidacije pomoću elektroda od nehrđajućeg čelika, 5 minuta elektrokoagulacije/ozoniranja pomoću željezovih elektroda, 15 elektrokoagulacije/ozoniranja pomoću aluminijevih elektroda te 15 minuta ozoniranja uklonjeno je 100% boje, mutnoće i UST, 94,5% KPK te 98,9% BPK5 a svi mjereni pokazatelji su zadovoljavali uvjete za ispust u okoliš.The paper presents a new approach which combines electrochemical methods and ozonation to wastewater treatment from potato processing in potato chips production. This wastewater is characterized by high values of total suspended solids (1517 mg dm-3), chemical oxygen demand (2240 mg dm-3) and biochemical oxygen demand (1780 mg dm-3) that exceed the limit values for discharges into the environment by 43.18 and 71 times, respectively. For the purpose of optimisation of this process, the paper investigated the impact of different electrode types (stainless steel, iron, aluminium), contact time (5-30 minutes) and amperage (30-100 A) on the degree of removal of these three parameters. Although the aluminium electrode set proved the most effective for the removal of these indicators, significantly better results were obtained by a combination of all three electrode types with simultaneous ozonation. After 10 minutes of electrocoagulation / electrooxidation with stainless steel electrodes, 5 minutes of electrocoagulation / ozonation with iron electrodes, 15 minutes of electrocoagulation / ozonation with aluminium electrodes and 15 minutes of ozonation, 100% colour, turbidity and TSS, 94.5% COD and 98. 9% BOD5 were removed, and all measured indicators met the requirements for discharges into the environment

Treatment of Acidic Mine Effluents and Wastewater from Ship Cleaning Facilities by Application of Red Mud

U radu je prikazan postupak obrade kiselog efluenta nastalog u toku eksploatacije i prerade bakrene rude kompleksa Borskih rudnika (Bor- Krivelj-Cerovo) pomoću crvenog mulja - otpadnog produkta iz procesa proizvodnje glinice u bivšoj tvornici glinice iz Obrovca te primjena nastalog otpadnog mulja za pročišćavanje otpadnih voda iz prališta brodova. Izvršena je karakterizacija otpadnih voda i crvenog mulja te su utvrđeni optimalni uvjeti uklanjanja ključnih pokazatelja iz otpadnih voda. Rudnička otpadna voda je karakterizirana niskom pH vrijednošću (3,21), visokom koncentracijom sulfata (10830 mg dm-3), visokim vrijednostima željeza (921 mg dm-3), mangana (107 mg dm-3), bakra (92 mg dm-3) i cinka (59 mg dm-3), dok su u otpadnoj vodi iz prališta brodova ključna onečišćivala bakar (34 mg dm-3), cink (59 mg dm-3) i boja (11470 PtCo). Obzirom na visok neutralizacijski i sorpcijski kapacitet crvenog mulja, njegovo miješanje s rudničkom otpadnom vodom u optimalnim omjerima dovodi do neutralizacije oba otpadna produkta te uklanjanja teških metala iz otpadne vode ispod graničnih vrijednosti. Pri optimalnim uvjetima uklanjanja (pH = 8; kontaktno vrijeme = 15 minuta) uklonjeno je više od 99,9% Cr, Mn, Fe, Cu i Zn te 65,5% sulfata. Preostali otpadni mulj je moguće ponovo upotrijebiti za pročišćavanje otpadnih voda iz prališta brodova visoko opterećenih bojama protiv obraštaja, a s jednom dozom mulja je moguće izvršiti pet ciklusa pročišćavanja s učinkovitošću uklanjanja ključnih pokazatelja preko 99%.The paper presents a procedure for treating acidic effluent generated during the exploitation and proce¬ssing of copper ore at the Bor mining complex (Bor-Krivelj-Cerovo) by application of red mud, a waste by-product of the alumina production process at the now-defunct alumina plant in Obrovac, and the application of the generated waste mud to treating wastewater from ship cleaning facilities. The characterisation of wastewater and red mud was carried out, resulting in the determination of optimal conditions for the removal of key indicators from wastewater. The acidic mine wastewater is characterised by a low pH value (3.21), high sulfate concentration (10,830 mg dm-3), high values of iron (921 mg dm-3), manganese (107 mg dm-3), copper (92 mg dm-3) and zinc (59 mg dm-3), whereas the key polluters in the wastewater from ship cleaning facilities include copper (34 mg dm-3), zinc (59 mg dm-3) and paint (11470 PtCo). Considering a high neutralisation and adsorption capacity of red mud, its mixing with mine drainage wastewater in op¬timal ratios leads to the neutralisation of both waste by-products and the removal of heavy metals from wastewater to below their limit values. Under the optimal removal conditions (pH = 8; contact time = 15 minutes), more than 99.9% of Cr, Mn, Fe, Cu and Zn as well as 65.5% of sulfates were removed. The remaining waste mud can be reused in the treatment of wastewater from ship cleaning facilities which has a high load of anti-fouling paint. A single mud dosage is sufficient for five treatment cycles and has a key indicator removal efficiency rate of over 99%

Electrochemical treatment of wastewater from the process of surface protection of metals

U radu je ispitana mogućnost primjene elektrokemijskih metoda (elektroredukcije, elektrokoagulacije, indirektne anodne oksidacije) korištenjem željezovog i aluminijevog seta elektroda sa ili bez dodatka elektrolita za obradu otpadne vode koja nastaje u procesu površinske zaštite metala. Otpadna voda je karakterizirana visokim vrijednostima cinka (2029 mg dm-3) i željeza (78,4 mg dm-3) te povišenim vrijednostima Cr(VI) (5,4 mg dm-3) i kemijske potrošnje kisika (820 mg dm-3) koje premašuju granične vrijednosti za ispust u okoliš za 1014, 39, 56, odnosno 6,6 puta. U svrhu optimizacije procesa u radu je ispitan utjecaj vrste elektroda (željezo, aluminij), kontaktnog vremena (5-30 minuta), mase elektrolita (0,5-1,5 g NaCl) te jakosti struje (20-50 A) na stupanj uklanjanja navedena četiri pokazatelja. Između dvije testirane elektrode, željezova se pokazala značajno efikasnijom u uklanjanju svih mjerenih pokazatelja, a naročito Cr(VI) i KPK. Statistički značajno bolji rezultati u uklanjanju KPK za obje elektrode su postignuti dodatkom elektrolita te porastom jakosti struje s 20 na 40 A. Najveći udio anorganskog onečišćenja se ukloni u prvih 5 minuta obrade. Najbolji rezultati su postignuti kombinacijom dviju elektroda uz dodatak klorida kao elektrolita. Nakon 15 minuta elektroredukcije/elektrokoagulacije/indirektne anodne oksidacije pomoću željezovih elektroda, 15 minuta elektrokoagulacije pomoću aluminijevih elektroda te 20 minuta koagulacije/flokulacije i oksidacije zrakom uklonjeno je 99,79% Cr(VI), 99,97% Fe, 98,23% Ni, 99,23% Cu, 99,999% Zn, 98,00% Pb i 86,46% KPK a svi mjereni pokazatelji su zadovoljavali uvjete za ispust u okoliš, dok su se izlazne koncentracije teških metala kretale od 0,009 do 0,023 mg dm-3.The paper investigated a possibility of implementing electrochemical methods (electroreduction, electrocoagulation, indirect anodic oxidation) by using iron and aluminium electrode sets, with or without the addition of electrolytes for treatment of wastewater generated in the process of surface protection of metals. The wastewater is characterized by high values of zinc (2029 mg dm-3) and iron (78.4 mg dm-3) as well as increased values of Cr(VI) (5.4 mg dm-3) and chemical oxygen demand (820 mg dm-3) that exceed limit values for discharge into the environment by 1014, 39, 56 and 6.6 times, respectively. In order to optimize the process, the paper investigated the impact of electrode type (iron, aluminium), contact time (5-30 minutes), electrolyte mass (0.5-1.5 g NaCl) and amperage (20-50 A) on the removal level of the stated four indicators. Of the two tested electrode types, iron electrodes proved to be significantly more efficient in the removal of all measured indicators, in particular Cr(VI) and COD. A statistically significant improvement of the results in COD removal for both electrode types was achieved by the addition of electrolytes and increased amperage from 20 to 40 A. The majority of inorganic pollution is removed in the first 5 minutes of treatment. The best results are achieved by a combination of the two electrode types, with the addition of chloride as an electrolyte. After 15 minutes of electroreduction / electrocoagulation / indirect anodic oxidation by iron electrodes, 15 minutes of electrocoagulation by aluminium electrodes and 20 minutes of coagulation / flocculation and oxidation by air, 99.79% Cr(VI), 99.97% Fe, 98.23% Ni, 99.23% Cu, 99.999% Zn, 98.00% Pb and 86.46% COD were removed. All measured indicators complied with the conditions for discharge into the environment whereas all output concentrations of heavy metals ranged from 0.009 to 0.023 mg dm-3

Mega2: validated data-reformatting for linkage and association analyses.

BACKGROUND: In a typical study of the genetics of a complex human disease, many different analysis programs are used, to test for linkage and association. This requires extensive and careful data reformatting, as many of these analysis programs use differing input formats. Writing scripts to facilitate this can be tedious, time-consuming, and error-prone. To address these issues, the open source Mega2 data reformatting program provides validated and tested data conversions from several commonly-used input formats to many output formats. RESULTS: Mega2, the Manipulation Environment for Genetic Analysis, facilitates the creation of analysis-ready datasets from data gathered as part of a genetic study. It transparently allows users to process genetic data for family-based or case/control studies accurately and efficiently. In addition to data validation checks, Mega2 provides analysis setup capabilities for a broad choice of commonly-used genetic analysis programs. First released in 2000, Mega2 has recently been significantly improved in a number of ways. We have rewritten it in C++ and have reduced its memory requirements. Mega2 now can read input files in LINKAGE, PLINK, and VCF/BCF formats, as well as its own specialized annotated format. It supports conversion to many commonly-used formats including SOLAR, PLINK, Merlin, Mendel, SimWalk2, Cranefoot, IQLS, FBAT, MORGAN, BEAGLE, Eigenstrat, Structure, and PLINK/SEQ. When controlled by a batch file, Mega2 can be used non-interactively in data reformatting pipelines. Support for genetic data from several other species besides humans has been added. CONCLUSIONS: By providing tested and validated data reformatting, Mega2 facilitates more accurate and extensive analyses of genetic data, avoiding the need to write, debug, and maintain one's own custom data reformatting scripts. Mega2 is freely available at https://watson.hgen.pitt.edu/register/