45 research outputs found
APPROBATION OF MICROBIALLY AVAILABLE PHOSPHORUS (MAP) DETERMINATION METHOD BY FLOW CYTOMETRY
Get PDFPhosphorus (P) is among the most important nutrients required for bacterial growth. It has a great influence on microbial activity even at very small concentrations. Existing chemical methods are not able to determine P at low enough concentrations and to quantify biologically available phosphorus fractions. Therefore, a method of microbially available phosphorus (MAP) determination is used to quantify the amount of P at concentrations below 20 Āµg/l. Additionally, this method determines the amount of P that can be directly used by microorganisms.
Originally it was determined by inoculating sample by Pseudomonas fluorescens (now Ps. brenneri) P17 strain and spread-plated on R2A agar for enumeration. Further, a more rapid method was developed by replacing heterotrophic plate count (HPC) by flow cytometry (FCM).
In this paper the use of FCM for MAP determination is validated and compared with HPC method. The results of calibration are presented. The original pure P17 strain was used as inoculum and standards with different PO4-P concentrations were inoculated at 30Ā°C. The gained yield factor by FCM was 1.59x108. FCM results showed strong correlation (R2=0.99) with HPC results, as pure culture was used. Therefore, flow cytometry is a rapid alternative to heterotrophic plate count method for microbially available phosphorus determination
Current research about biological stability of drinking water in the Riga water supply system
No full textLiteratÅ«ras apskats par faktoriem, kas ietekmÄ dzeramÄ Å«dens mikrobioloÄ£isko stabilitÄti
ÅŖdens patÄriÅa uzskaite RÄ«gas pilsÄtas dzÄ«vokļos
No full textRakstÄ atspoguļota Å«dens skaitÄ«tÄju apsekoÅ”ana RÄ«gas pilsÄtas dzÄ«vojamo mÄju dzÄ«vokļos. ÅŖdens skaitÄ«tÄju precizitÄte atkarÄ«bÄ no to montÄžas veida pÄrbaudÄ«ta uz stenda. Doti ieteikumi dzeramÄ Å«dens uzskaites sistÄmas pilnveidoÅ”anai dzÄ«vokļos
Ways of Water Counting Significantly Effect Drinking Water Consumption in Riga City (Latvia)
No full textPÄtÄ«jums par dzeramÄ Å«dens uzskaites problÄmÄm RÄ«gÄ
ÅŖdens patÄriÅa uzskaite RÄ«gas pilsÄtas dzÄ«vokļos = Counting of Water Consumption on Apartment Buildings in Riga City
No full textThe Full-Scale Study on Phosphorus Addition to Biologically Activated Carbon Filters
No full textDarbÄ apskatÄ«ta fosfora dozÄÅ”anas ietekme uz organisko vielu izdalÄ«Å”anu bioloÄ£iski aktÄ«vÄs ogles filtros. PÄtÄ«jums veikts Å«dens attÄ«rÄ«Å”anas iekÄrtÄs, kurÄs mikroorganismu attÄ«stÄ«bu limitÄ fosfors. Organisko vielu izdalÄ«Å”anu biofiltros mÄrÄ«jÄm nosakot kopÄjÄ organiskÄ oglekļa (TOC) koncentrÄciju, Ä·Ä«miskÄ skÄbekļa patÄriÅu un ultraviolÄto absorbciju. Mikroorganismu koncentrÄciju biofiltru izplÅ«dÄ noteicÄm mÄrot heterotrofo koloniju skaitu. TOC koncentrÄcija biofiltrÄ ar fosfora (50 Āµg P/l) dozÄÅ”anu bija 5.13 mg l-1 un filtrÄ bez dozÄÅ”anas 5.52 mg l-1. HPC izplÅ«des Å«denÄ« no biofiltra ar fosfora dozÄÅ”anu bija par vienu kÄrtu lielÄks nekÄ filtrÄ bez fosfora dozÄÅ”anas jeb 2573 kolonijas veidojoÅ”Äs vienÄ«bas ml-1 and 265 kvv ml-1katrÄ. PÄtÄ«jums parÄdÄ«ja, ka nebija ievÄrojamas statistiskas atŔķirÄ«bas organisko vielu izdalÄ«Å”anai filtrÄ ar fosfora dozÄÅ”anu un filtrÄ bez dozÄÅ”anas
AksiÄlÄs dispersijas ietekme uz dzeramÄ Å«dens kvalitÄtes izmaiÅÄm dzeramÄ Å«dens apgÄdes tÄ«klÄ
No full textTÄ«rs dzeramais Å«dens ir jebkuras civilizÄcijas pamatÄ, lÄ«dz ar to tÄ kvalitÄtei ir jÄpievÄrÅ” ļoti liela uzmanÄ«ba. Lai arÄ« dzeramÄ Å«dens kvalitÄte Å«dens sagatavoÅ”anas un attÄ«rÄ«Å”anas iekÄrtÄs ir augsta, tÄ mÄdz pasliktinÄties dzeramÄ Å«dens apgÄdes tÄ«klÄ. PasaulÄ problÄmas, kas saistÄ«tas ar dzeramÄ Å«dens estÄtiskÄm Ä«paŔībÄm, dzÄ«vÄ«bai bÄ«stamu dezinfekcijas blakusproduktu samazinÄÅ”anu, kÄ arÄ« attiecÄ«ga rÄ«cÄ«bas plÄna sagatavoÅ”anai, gadÄ«jumos, ja patÄrÄtÄji saindÄjas ar nekvalitatÄ«vu dzeramo Å«deni, arvien biežÄk parÄdÄs prasÄ«bÄs dzeramÄ Å«dens apgÄdes sistÄmu apkalpojoÅ”ajiem uzÅÄmumiem. Å Ä«s visas problÄmas ir saistÄ«tas ar dzeramÄ Å«dens kvalitÄtes izmaiÅÄm dzeramÄ Å«dens apgÄdes tÄ«klÄ. Å Ädu problÄmu risinÄÅ”anai un prognozÄÅ”anai tiek izmatotas datorsimulÄcijas. DatorsimulÄcijÄm izmantotÄs modelÄÅ”anas programmas ir neprecÄ«zas, jo tÄs nespÄj precÄ«zi modelÄt, kÄ dzeramÄ Å«dens apgÄdes sistÄmÄ izplatÄs Ä·Ä«misko vai bioloÄ£isko vielu daļiÅas, jo visÄs lÄ«dz Å”im izstrÄdÄtajÄs modelÄÅ”anas programmÄs ir iestrÄdÄts pieÅÄmums, ka daļiÅas cauruļvados kustas tikai ar advekcijas mehÄnisma palÄ«dzÄ«bu un netiek Åemta vÄrÄ aksiÄlÄs dispersijas ietekme. Tas ir, tiek pieÅemts, ka daļiÅas kustas reizÄ ar Å«dens daļiÅÄm.
Cauruļvados plÅ«stoÅ”u Ŕķidrumu aksiÄlÄ jeb garuma dispersija rodas masas transporta procesÄ, kad piesÄrÅojuma daļiÅas Å«denÄ« nevienmÄrÄ«ga plÅ«smas ŔķÄrsgriezuma Ätruma sadalÄ«juma ietekmÄ izpleÅ”as garenvirzienÄ.
Darba mÄrÄ·is ir ar mÄrÄ«jumiem speciÄli izveidotÄ miniatÅ«rÄ Å«densapgÄdes tÄ«klÄ, noskaidrot aksiÄlÄs dispersijas ietekmi uz piesÄrÅojuma izplatÄ«bu Å«denÄ« un lÄ«kumu ietekmi uz to, kÄ arÄ« pilnveidot Å«densapgÄdes tÄ«klu modelÄÅ”anÄ izmantoto programmu Epanet 2.0 iekļaujot tajÄ aksiÄlÄs dispersijas ietekmi.
Lai noteiktu potenciÄla piesÄrÅojuma izplatÄ«bu, tiek veikti eksperimenti pielietojot tÄ saucamo ātreiseruā metodi. Eksperimentos Å«dens apgÄdes sistÄmÄ tiek ievadÄ«ts Ŕķidrums ar paaugstinÄtu elektrovadÄ«tspÄju (EVS), kurÄ pÄc tam tÄlÄk tÄ«klÄ tiek mÄrÄ«ta ar rokas un on-line EVS mÄrÄ«tÄjiem (Cond 315i, (WTW, Germany) ar mÄrÄ«jumu precizitÄti 1.5% un HACH 3400scTM (Dr.Bruno Lange GmbH&Co, Germany) ar mÄrÄ«jumu precizitÄti 2 %). KopumÄ tika veikti 48 eksperimenti, lai noskaidrotu piesÄrÅojuma izplatÄ«Å”anÄs atkarÄ«bu no lÄ«kumu skaita cauruļvadÄ, attÄluma un plÅ«smas Ätruma. Eksperimentu veikÅ”anai tiek izmantota daļa no RTU ÅŖITK telpÄs esoÅ”Äs pilota iekÄrtas, kÄ arÄ« tika speciÄli konstruÄts 36 metru garÅ” taisns cauruļvads. AttÄlÄ redzama atŔķirÄ«ba starp modelÄto piesÄrÅojuma izplatÄ«bu un eksperimentÄli noteikto. Darba rezultÄti ļaus paredzÄt citu vielu piemÄram Bacillus subtilis sporu, izplatÄ«bu minÄtajÄ pilota iekÄrtÄ, kÄ arÄ« dos iespÄju pilnÄ«gÄk izprast vielu koncentrÄciju izmaiÅas Å«densapgÄdes sistÄmÄs
Problem of DOC Removal during Biological Treatment of Surface Water with a High Amount of Humic Substances
No full textChemical precipitation in combination with biological treatment is a commonly used method for removal of turbidity and dissolved organic carbon (DOC) from drinking water. DOC is largely removed during biological treatment, which includes ozonation and filtration through a biologically active carbon (BAC) filter. Ozone converts humic substances into a biologically labile form that is mineralised by bacteria living in the following BAC filter. This study shows that this approach is often not efficient for removal of DOC from waters with a high amount of humic substances. During chemical treatment, the microbiologically available phosphorus is very efficiently removed, which results in shortages of phosphorus needed for bacteria to mineralise carbon in BAC filters. To enhance removal of DOC by biological treatment, addition of phosphorus prior to the BAC filters should be considered
Accumulation of Loose Deposits in Pipe Segments
No full textLoose deposits in drinking water distribution systems (WDS) on nowadays cause serious problem causing accumulation of bacteria and discoloration. The present study was designed to calculate amount of loose deposits accumulated in WDS of cast iron, polyethylene and polyvinylchloride pipes. The loose deposits were resuspended and collected during planned unidirectional flushing of isolated pipe segments. The flow (Siemens Sitrans FM MAG 8000 (Siemens Energy & Automation Inc., Germany)) and turbidity (Hach 2100P, Dr. Bruno Lange GmbH&Co, DĆ¼sselfdorf, Germany) during flushing was measured with online instruments. The average velocities of flushing ranged from 0.2-2.34 m/s and shear stress 0.43N/m2 -2.05N/m2 acting on pipe walls. The calculations of hydraulic values indicated that the different types of pipes has various potential of particles and new polyethylene pipes sometimes has even more deposits than old cast iron pipes. The concentrations of loose deposits per meter of pipe were observed from 0.05kg/m till 2.4kg/m. Results showed that flow velocity of flushing and daily hydraulic regime are the key factors for accumulation of loose deposit amount in pipe segments. Dead-end treads has more loose deposits than transit without influence of pipe material. More attention should be paid for model validations, so the daily flow regime could indicate critical pipe segments, where most of sediments are settled
Evaluating the Potential of Biofilm Control in Water Supply Systems by Removal of Phosphorus from Drinking Water
No full textRakstÄ apskatÄ«ti eksperimenti bioplÄves reaktorÄ Propella dzeramÄ Å«dens apgÄdes sistÄmÄ RÄ«gÄ. PÄtÄ«jumÄ konstatÄta mikrobioloÄ£iski pieejamÄ fosfora ietekme bioplÄves attÄ«stÄ«bai dzeramÄ Å«dens sadales sistÄmÄs
