Surfactants in the Environment Ivankovic, Tomislav; Hrenovic, Jasna
Arhiv za higijenu rada i toksikologiju,
03/2010, Letnik:
61, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Surfactants are a diverse group of chemicals that are best known for their wide use in detergents and other cleaning products. After use, residual surfactants are discharged into sewage systems or ...directly into surface waters, and most of them end up dispersed in different environmental compartments such as soil, water or sediment. The toxic effects of surfactants on various aquatic organisms are well known. In general, surfactants are present in the environment at levels below toxicity and in Croatia below the national limit. Most surfactants are readily biodegradable and their amount is greatly reduced with secondary treatment in wastewater treatment plants. The highest concern is the release of untreated wastewater or wastewater that has undergone primary treatment alone. The discharge of wastewater polluted with massive quantities of surfactants could have serious effects on the ecosystem. Future studies of surfactant toxicities and biodegradation are necessary to withdraw highly toxic and non-biodegradable compounds from commercial use and replace them with more environmentally friendly ones.
Surfaktanti ili površinski aktivne tvari raznolika su skupina molekula najpoznatijih po uporabi u sastavu deterdženata i ostalih sredstava za pranje i _išćenje. Nakon uporabe u kućanstvu ili industriji, surfaktanti se ispuštaju u kanalizacijski sustav ili izravno u površinske vode te većina surfaktanata završi raspršena u vodi, sedimentu ili tlu. Toksi _ni utjecaj surfaktanata na vodne organizme dobro je istražen i opisan u literaturi. U većini slu _ajeva surfaktanti su u okolišu prisutni u koncentracijama nižim od toksi _ne te nižim od maksimalne koncentracije dopuštene hrvatskim zakonskim odredbama. Većina surfaktanata klasificirana je kao biološki razgradiva i njihova se koncentracija znatno smanjuje biološkom obradom otpadne vode pa je najveći rizik za okoliš ispuštanje prethodno pro _išćene ili nepro _išćene otpadne vode. Takva otpadna voda opterećena visokim koncentracijama surfaktanata može nepovoljno utjecati na okoliš. Potrebno je prou _avati toksi _nost i biološku razgradnju surfaktanata u svrhu uklanjanja visoko štetnih i biološki nerazgradljivih surfaktanata iz komercijalne uporabe te njihovu zamjenu tvarima manje štetnim za okoliš.
Biological air treatment devices, biofilters, of four different structures with different origin charges, composed of natural zeolite granules, foam cubes and wood chips, were used for the ...experimental investigation. Biological and ad-sorptive air treatment methods are employed to clean the air from volatile organic compounds by mixing foam and zeolite with wood chips. The use of complex cleaning technologies improves the efficiency of the device and extends the useful life of a charge. The investigation showed that microorganisms predominant in the process of biocleaning could also propagate in the charges of inorganic origin composed of natural zeolite. The dependences of biofilter treatment efficiency on the nature, concentration and filtration time of the fed pollutant were determined when cultivating associations of spontaneous microorganisms in a charge. The best filtration efficiency of the charge was achieved when acetone-polluted air was fed into the device at a speed of 0.3 m/s. The treatment efficiency of a biofilter with a humidifying chamber reached 98% when cleaning the air from acetone with an initial concentration of the pollutant of 305 mg/m
3
. The cleaning efficiency of the device increases when reducing the concentrations of pollutants fed into the device and increasing the time of their filtration.
The investigation was carried out using a biological air-treatment device, i.e. a biofilter with an aeration chamber filled with water saturated with biogenic elements. To accelerate the absorption ...of organic compounds, air polluted with volatile organic compounds is directed to a water reservoir installed in the lower part of the filter where organic compounds are destructed. In the process of aeration, microorganisms propagate in the chamber, degrading part of pollutants to harmless products, carbon dioxide and water. Since all hydrocarbons are water-soluble, the aeration chamber is the first phase in a hydrocarbon degradation process. Application of such a polluted air-feeding model improves the sorption qualities of a charge. When relative air humidity reaches 100%, water-drops evenly distribute over the entire surface area of the charge and improve the activity of microorganisms. Having passed through the aeration chamber, polluted air is filtered via charges of a different origin, composed of zeolite, foam, wood chips or their mixtures. The carried out experiment shows that the best charge filtering capacity is achieved when supplying air polluted with acetone at the rate of 0.1 m/s. At the initial pollutant concentration of 115 mg/m
3
the biofilter treatment efficiency reached 96%. The aeration chamber installed in the biofilter increases both microbiological activity of the charge and air treatment efficiency.
A new composting technology of waste with high fat content was developed in JSC "Biocentras". The composting technology of fat-contaminated waste is based on the use of fat-oxidizing microorganisms. ...Developed technology is commended for cleaner production/pollution prevention approach as well as meets strict environmental and hygiene requirements. The composting process was investigated for the process optimization by applying the response surface methodology. Values of parameters of composting process were monitored in lab-scale composters. The optimal composition of the composing mixture was determined: the initial fat content - 5%, the concentration of bacterial preparation cells - 10
9
CFU/g, the quantity of structural materials - 9.5%. Fat degradation rate slowed down 3 times if the initial fatty concentration increased from 5% to 20%. Concentrated fatty-waste disposal site prototype was designed. Composting process duration lasted 1 to 1.5 year.
Many modern technologies for treatment of soil polluted with oil products are developed through creation of new and efficient bio-agents that help to degrade oil products. Another trend in ...development of new technologies aims to speed up the growth of soil microorganisms, this way accelerating biodegradation of oil products without the help of introduced microorganisms. The biodegradation of diesel fuel and heavy fuel oil was tested in the soil using chemical additives (oxidizing agents). The tests aimed to ascertain the impact of H
2
O
2
, KMnO
4
and MnSO
4
on residual concentrations of heavy fuel oil and diesel fuel, and the total number of microorganism colonies, as well as the number of oil-oxidizing microorganism colonies in the soil. After the statistical analysis of the data obtained during the experiment, a statistically significant (p <0.05) difference between control samples and samples with introduced chemical additives was obtained both in the soil contaminated with heavy fuel oil and diesel fuel. It was determined that use of KMnO
4
as an oxidizing agent in the soil contaminated with heavy fuel oil, resulted in 3 times less statistically significant residual value of the heavy fuel oil concentration than in the control samples; however, no statistically significant difference was found between oxidizing agents (potassium permanganate and hydrogen peroxide). In cases where soil is contaminated with diesel fuel, there is a significant difference between KMnO
4
and H
2
O
2
, which shows that potassium permanganate has a bigger impact on the degradation of diesel fuel than hydrogen peroxide. The residual concentration of diesel fuel in the samples with KMnO
4
was 3 times less statistically significant than in the samples with H
2
O
2
, and 5 times less than in the control samples. The use of both - KMnO
4
and MnSO
4
- created more favourable conditions for biodegradation of diesel fuel and heavy fuel oil in the soil. A positive growth of microorganisms using Mn of different valence was observed during the entire course of experiment. Various chemical additives could be used in the technological process of biotreatment, when soil is contaminated with oil products.
The complex, effective and innovative cleaning technology for lipid-rich wastewater and pipelines contaminated by lipids, was developed. For this purpose, laboratory experiments were performed to ...verify the efficiency of bacterial preparation (Enterobacter aerogenes E13, Arthrobacter sp. N3 and Bacillus coagulans S1) to degrade the grease in water and in drainpipes. The results showed that selected microorganisms intensively degrade grease to light odourless precipitate, water and CO
2
, thus could be applied in industry. For optimization of technological cleaning processes, the response surface methodology was used. The optimal parameters for biological model wastewater treatment were determined: concentration of grease − 4.5-6.0 g/l, amount of bacterial preparation −5.5-6.0%, pH - 8-9. Due to optimization, the grease degradation rate increased by 20-30%. The optimization of drainpipe cleaning technology was achieved in two stages. During the first stage, the experiments were performed in laboratory flasks; during the second stage, optimized cleaning process was tested in a pilot plant. The following optimal parameters were set: pH - 8, amount of bacterial preparation -1.25 l/m
2
and harness of water - 0.0 mmol/l. In water of medium hardness, the rate of biodegradation process is 15-20% less. A satisfactory efficiency of grease biodegradation was achieved in the pilot plant: the 86.7% of grease were digested in 21 days. Besides, living microorganisms were detected inside the clean drainpipe.
Microorganisms can reproduce only in such substrata which contain a certain amount of water and dissolved nutritious substances. Therefore, it is necessary to search for such charges that are ...distinguished by a large filtering surface and good humidity-retaining properties. In experiments three types of materials - wood, zeolite and foam - were used as a charge for the biological air-cleaning process. The charges were mixed up to maintain humidity necessary for the microorganisms in the biofilter as long as possible. The charges were placed into three different cassettes in the biofilter. The wood charge consisted of wood chips of 10-15 mm and that of zeolite contained 10-12 mm of zeolite granules. The foam rubber was cut into separate cubes each having the dimensions of 30×30×20 mm. Dependence of the charge humidity on the airflow rate, temperature, time and charge thickness was determined in the work. During the experiments the airflow rate reached 0.1-0.6 m/sec., and the temperature ranged from 15 to 35 °C. Foam showed the best sorption properties, but a better distribution of humidity was found in the wood-chip charge.
In order to carry out an experimental investigation a biological air-treatment device was used, namely, a biofilter with a charge of a different origin composed of zeolite, foam and wood chips. When ...mixing foam and zeolite together with wood chips for air treatment from volatile organic compounds, not only a biological but also adsorptive air-treatment method is used. Using complex treatment technologies the device efficiency and the charge service period are improved. The investigation has shown that microorganisms, being predominant in the bio-treatment process, can breed in charges of on inorganic origin made of natural zeolite and foam. While cultivating spontaneous microorganism associations in the charge, biofilter treatment efficiency was determined to be dependent on the sort of the supplied pollutant, concentration and filtration period. The charge filtration function was most efficient at a velocity of 0,1 m/s when the device was supplied with acetone-polluted air. Cleaning air from acetone, when the original concentration of the pollutant was 103 mg/m
3
, the filter treatment efficiency reached 95%. When the concentration of pollutants supplied into the biofilter is reduced and the filtration period is increased, the device treatment efficiency increases as well.
This article presents the use of natural abundance stable isotope (hydrogen, carbon, nitrogen, oxygen, chlorine) analysis data as a tool for providing important information about the origin of ...contaminants, the contribution of different sources to a multi-source plume, characterisation of their complex transport (rate and mechanisms) and for evaluating the success of contaminated site remediation. Isotopic signatures of contaminants are useful tracers of their sources, while isotopic fractionation can be used to quantitatively assess the progress of an environmental process such as biodegradation. This new isotopic approach is reliable and can offer more information than traditional techniques in pollutant migration studies, particularly after waste disposal. During biological degradation of any organic compound, molecules containing lighter isotopes are degraded, and the portion of heavier isotopes in the substrate is increased, identifying specific microbial roles in biogeochemical cycling. Since isotopic fractionation is proportional to degradation, depending on the type of contamination, a microbial degradation of 50% to 99% of the initial concentration can be quantified using isotope ratio measurements.
Cilj ovog rada je da se prikaže korištenje podataka analize prirodne obilnosti stabilnih izotopa (vodika, ugljika, dušika, kisika i klora) kao alata za dobivanje važnih informacija o porijeklu onečišćujućih tvari, doprinosu različitih multikomponentnih onečišćivača, karakterizaciji njihova kompleksnog transporta (brzine i mehanizma) i praćenja uspjeha remedijacije onečišćenih mjesta. Izotopski sadržaji onečišćujućih tvari koriste se kao traseri za određivanje njihovih izvora, dok se izotopsko frakcioniranje može iskoristiti za kvantitativnu procjenu toka procesa kao što je biodegradacija. Takav nov izotopski pristup je pouzdan i nudi više informacija od tradicionalnih tehnika kontrole putovanja onečišćivala, napose nakon odlaganja opasnog otpada na zemljištu. Za vrijeme biodegradacije nekog organskog spoje molekule koje sadržavaju lake izotope lakše se degradiraju, a dio težih izotopa u supstratu se povećava, što upućuje na mikrobiološku ulogu u biokemijskom ciklusu. Kako je izotopsko frakcioniranje proporcionalno degradaciji zavisno od tipa onečišćenja, korištenjem podataka mjerenja izotopskih odnosa može se procijeniti mikrobiološka degradacija od 50 % do 99 % od početne koncentracije.
Pasaulyje kasmet susidaro milijonai tonu ivairiausiu organiniu atlieku. Tačiau bioduju gamybai tinka tik tam tikra ju dalis, kita dalis del ivairiu priežasčiu negali būti panaudota biodujoms gaminti ...ir yra ivairiais metodais utilizuojama arba kaupiama savartynuose. Mūsu šalyje susidarančios organines atliekos dažnai yra sumaišomos su kalnais ivairiausiu kitos rūšies buitiniu bei gamybiniu atlieku. Todel, norint sekmingai pritaikyti anaerobinio organiniu atlieku apdorojimo technologijas ir kuo labiau sumažinti šiu atlieku kenksminga poveiki aplinkai bei gauti didžiausia ekonomini efektyvuma, šias atliekas būtina rūšiuoti (geriausia iš pat pradžiu ju nesumaišyti su kitomis atliekomis). Aprašomi eksperimentiniai tyrimai su vaisiu, daržoviu ir mesos atliekomis, atlikti jas sluoksniuojant su pjuvenomis ir keramzitu. Eksperimento metu stebimos išsiskiriančio metano bei deguonies koncentracijos ir fiksuojami temperatūru pokyčiai talpyklose. Nustatyta, kad biodegradacijos procesas leteja atliekas sluoksniuojant su keramzitu.
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