Statistical analysis of the equivalent design rainfall

Statistical analyses of rainfall data are used for the design of sewerage systems and pump-stations, for the evaluation of the duration and the frequency of overflow in runoff detention facilities, for the determination of the critical influence on a municipal wastewater-treatment plant or for the protection of watercourses from storm-water runoff (e.g., from highways). The basic data in this calculation are the intensity and the duration of a rainstorm. Different procedures used in the analysis of Equivalent Design Rainfall (EDR) in Slovenia and abroad are described. The stochastic model used is presented in more detail because of its applicability for the determination of the probability of the occurrence of partial rainfalls of higher frequencies and the determination of the lower limit of rainfall evaluation. Computation procedures and the results of the evaluation of rainfall data according to the stochastic model are presented for Ljubljana

Relating nutrient ratios to mucilage events in Northern Adriatic

The north western part of the northern Adriaticexhibits eutrophic to mesotrophic characteristicswith recurrent algal blooms and quiteunpredictable mucilage events. To contribute to theunderstanding of the mucilage events in thenorthern Adriatic, a machine learning algorithmfor induction of regression trees was applied to adata set comprising physical and chemicalparameters, measured at six stations on the profilefrom the Po River delta (Italy) to Rovinj on thewestern Istrian coast (Croatia). A modeldescribing the connection between the TIN/PO 4ratio, considered as a necessary factor andsometimes even a trigger for mucilage events, andthe environmental conditions in northern Adriaticwas elaborated. The model for TIN/PO 4 ratioconfirmed the assumption that the mucilage eventsare connected with the changes of this ratio in thesystem. This indicates that at certain levels of Plimitation (TIN/PO 4 signal indicate) mucilageevent frequency increases. The model also revealswhich triggers are responsible (salinity andtemperature) for the changes of the TIN/PO 4 ratioas well as their threshold values. As contrasted toto the TIN/PO 4 ratio, the mucilage events could notbe attributed to the TIN/SiO 4 ratio

Performance analysis of small wastewater treatment plants for mountain lodges

This paper presents the operation of seven small municipal wastewater treatment plants (WWTP) at mountain huts all over Slovenia. The studied WWTPs were selected as a representative sample based on inventory of all WWTPs of Alpine Association of Slovenia. Performance efficiency of selected WWTPs was carried out on the basis of 20 parameters obtained by field measurements and laboratory analyses of wastewater, which was sampled in winter and summer. Together, we carried out 200 hours of field research in the mountains.\ud Based on the assessment of the operation efficiency of selected WWTPs, proposals for their improvements were suggested. In addition to improvement proposals, the paper includes suggestions for Slovenian legislation complementation, proposals for engineers and planers, operators, producers, and suggestions for improvement and standardization of field measurements and sampling. This paper presents the first extensive survey of WWTP performance in the frame of Alpine Association of Slovenia and can serve as a basis for further studies of WWTPs at mountain huts, characterized by high fluctuations of influent wastewater.\ud The paper presents research, primarily based on field work, the key results and describes the main findings and unanswered questions. It also presents the key changes in the frame of new Regulation (2012) regarding mountain huts or non-permanent inhabited buildings.\u

Use of machine learning for determining phytoplankton dynamic on station RV001 in front of Rovinj (Northern Adriatic)

The paper describes the use of machine learning (ML) and discusses various approaches in modeling phytoplankton based on data from station RV001 in front of Rovinj which well represents the main processes in the open northern Adriatic (NA). Station RV001 is an example of oligotrophic seawater in NA. In order to contribute to the understanding of phytoplankton dynamics at the observation station, based on data covering physical, biological and chemical parameters, ML techniques were used. The final result is a construction of models in the form of regression and model trees, respectively; there were models constructed to be used to explain the dynamics of phytoplankton concentrations at the mentioned station as a result of independent environmental variables. Models in an affordable way combine and show knowledge collected by measurements during 35 year period, which have greatly contributed to a better understanding of ecosystem functioning

Možnosti odstranjevanja ogljikovega dioksida iz zraka

Excessive atmospheric greenhouse gas concentrations currently represent an insolvable problem, as their quantities being emitted into the atmosphere far exceed the planet’s ability to extract them. In the realm of politics and the industry, management of this issue (eco-management) is being handled in what is a completely one-sided manner. The emphasis is almost entirely placed on ways to lower greenhouse gas emissions into the atmosphere, while the possibilities of extracting excess greenhouse gases from the atmosphere are being overlooked. As a consequence, resources are being predominantly devoted to the development of new technologies that generate lower greenhouse gas emissions. While these technologies can provide immediate relief, there is no reason to believe they are the most economically efficient options available. There are myriad new technologies in various stages of development that will be capable of extracting excess greenhouse gas emissions from the atmosphere, much like water treatment plants extract excess pollutants from water.Previsoka vsebnost toplogrednih plinov v zraku predstavlja trenutno nerešljiv problem, ker jih narava ni sposobna tako hitro odstranjevati iz ozračja, kot se v ozračje sproščajo. Upravljanje z okoljem (eko-management) na političnem in gospodarskem nivoju se ukvarja s tem vprašanjem povsem enostransko. Poudarek je skoraj izključno na tem, kako zmanjšati emisije toplogrednih plinov v ozračje, skoraj popolnoma pa je zanemarjen vidik odstranjevanja le-teh iz ozračja. Posledično se predvsem podpira razvoj novih tehnologij, pri katerih nastanejo bistveno manjše emisije toplogrednih plinov. To so trenutne rešitve, za katere pa ni nujno, da bodo v prihodnosti tudi ekonomsko najučinkovitejše. V razvoju so namreč nove tehnologije, ki bodo odstranjevale odvečno količino toplogrednih plinov iz zraka, podobno kot to počnejo čistilne naprave z onesnaževali v vodi

Effect of advanced oxidation processes (AOPs) on the biodegradability of municipal wastewater for its reuse in the textile industry

Reuse of treated municipal wastewater to supplement part of fresh water is becoming more and more\ud important. However, treated water can contain some pollutants that cannot be successfully removed with\ud classical biological wastewater treatment processes. Aim of the study presented was to assess whether\ud advanced oxidation processes (AOPs) and special enzymes enhance biodegradation of municipal wastewater\ud and if treated municipal wastewater can be reused in the production process of textile industry. To test\ud biodegradability we used a small-scale pilot wastewater treatment plant (PWWTP) consisting of six parallel\ud bioreactors with suspended activated sludge (CAS type). Bioreactors were supplied with untreated municipal\ud wastewater, AOP-treated municipal wastewater and AOP-treated municipal wastewater with addition of\ud special enzymes. The results showed that AOPs contributed to better biodegradation while enzymes did not.\ud Municipal wastewater treated by a combination of AOP and biological treatment was not suitable for reuse\ud in the dyeing process, but could potentially be reused in some other processes in the textile industry

Recycling of textile wastewaters treated with various combinations of advanced oxidation processes (AOP)

Advanced oxidation processes (AOPs) are widely used for treatment of wastewaters containing recalcitrant\ud organic compounds from industrial and municipal wastewater; many advantages over other technologies\ud have been found and good treatment results have been obtained so far. Approaches which reduce fresh water\ud consumption are especially important for regions with shortage in fresh water resources and in high waterconsuming\ud industries. Within AOP4Water (a multinational project funded under the CORNET programme),\ud combinations of different AOP methods are being tested with the final aim to enable cost-efficient reuse of\ud AOP-treated effluents from textile industry. The key to wastewater reuse lies in increasing the efficiency of\ud AOP treatment that ensures the required water quality and decreasing operational costs. In the present study\ud a series of experiments was performed with real textile industry effluents using a single AOP method as well\ud as combinations. Following AOP treatments were applied: ozone (O3); O3+ UV irradiation (UV); O3 +\ud hydrogen peroxide (H2O2); and O3 + H2O2 + UV. The most effective combination for colour and COD\ud removal was O3 + H2O2 + UV with 75% - 86% of colour removal and 15% of COD removal

Vpliv naprednih oksidacijskih procesov (AOPs) na biorazgradljivost komunalne odpadne\ud vode za njeno ponovno uporabo v tekstilni industriji

Reuse of treated municipal wastewater to supplement part of fresh water is becoming more and more\ud important. However, treated water can contain some pollutants that cannot be successfully removed with\ud classical biological wastewater treatment processes. Aim of the study presented was to assess whether\ud advanced oxidation processes (AOPs) and special enzymes enhance biodegradation of municipal wastewater\ud and if treated municipal wastewater can be reused in the production process of textile industry. To test\ud biodegradability we used a small-scale pilot wastewater treatment plant (PWWTP) consisting of six parallel\ud bioreactors with suspended activated sludge (CAS type). Bioreactors were supplied with untreated municipal\ud wastewater, AOP-treated municipal wastewater and AOP-treated municipal wastewater with addition of\ud special enzymes. The results showed that AOPs contributed to better biodegradation while enzymes did not.\ud Municipal wastewater treated by a combination of AOP and biological treatment was not suitable for reuse\ud in the dyeing process, but could potentially be reused in some other processes in the textile industry

Raziskava onesnaženosti odpadnih voda v slovenski tekstilni industriji in ekonomska upravičenost učinkovitega čiščenja

Wastewaters from textile industry are generally highly loaded. Their load can be determined by engineering standards, stand­ards of best available technologies and annual operational monitoring. Investigation presented covers all textile factories in Slovenia obligated by the Directive 96/61/ES on integrated pollution prevention and pollution control; two textile factories in Slovenia were studied in details. In the majority of discussed textile factories significantly higher pollution emissions that would be expected on the basis of engineering and Best Available Techniques (BAT) standards were found. The reason is outdated technological equipment which departs significantly from BAT standards. As the textile factories in Slovenia are mostly con­nected to public sewer networks which are terminated by central treatment facility, economic viability of installing treatment plants for efficient wastewater pre-treatment is questionable. It is mandatory to achieve the required criteria for discharge into public sewers. More efficient treatment is justified only when it is cost efficient. Economic viability is assessed in terms of costs, which consist of expenses for fresh water supply, environmental taxes, charges for wastewater collection and wastewater treatment and expenses of effective treatment within the factories.Odpadne vode iz tekstilne industrije so praviloma zelo obremenjene. Njihovo obremenitev lahko ugotavljamo preko inženirskih normativov, normativov najboljših razpoložljivih tehnologij ter z letnimi obratovalnimi monitoringi. Raziskava zajema vse zavezance na podlagi Direktive 96/61/ES o celovitem preprečevanju in nadzorovanju onesnaževanja okolja iz tekstilne industrije v Sloveniji, podrobneje pa smo raziskali dve tekstilni tovarni. Pri večini obravnavanih tekstilnih tovarn smo ugotovili bistveno večje emisije, kot bi jih pričakovali na podlagi inženirskih in Best Available Techniques (BAT) normativov. Razlog je zastarela tehnološka oprema, ki znatno odstopa od BAT normativov. Ker so v Sloveniji tekstilne tovarne večinoma priključene na javna kanalizacijska omrežja, ki se zaključijo s centralnimi čistilnimi napravami, se pojavlja vprašanje ekonomske upravičenosti postavitve učinkovitih čistilnih naprav za predhodno čiščenje odpadnih voda. Obvezno je doseganje pred­pisanih kriterijev za izpust v javno kanalizacijo. Bolj učinkovito čiščenje pa je upravičeno le, če je to ekonomsko upravičeno. Ekonomsko upravičenost presojamo iz vidika stroškov, ki so sestavljeni iz cene sveže vode, okoljske dajatve, cene za odva­janje in čiščenje odpadne vode ter stroškov za učinkovito lastno čiščenje