Application of faecal stretococci in the microbiological assessment of composted sewage sludge sanitization

Ze względu na obecność w surowym osadzie ściekowym zarówno niebezpiecznych związków chemicznych, jak i patogennych drobnoustrojów, musi być on poddany procesowi uzdatniania. Wykorzystanie w rolnictwie niewłaściwie higienizowanych osadów ściekowych stanowi zagrożenie dla środowiska oraz zdrowia ludzi i zwierząt. Celem badań była mikrobiologiczna ocena skuteczności kompostowania osadów ściekowych wraz z odpadami z miejskich terenów zielonych w technologii kontenerowej, na podstawie tempa inaktywacji paciorkowców kałowych. Doświadczenie prowadzono w trzech cyklach - wiosną, latem i jesienią. Bakterie wskaźnikowe wprowadzano do kompostowanego materiału w postaci nośników. W czasie trwania procesów kompostowania stwierdzono całkowitą eliminacje paciorkowców kałowych w nośnikach z górnej i środkowej warstwy biomasy we wszystkich cyklach. Teoretyczny czas przeżywalności bakterii wynosił od 19 do 49 dni. Latem i jesienią w nośnikach zwarstwy dolnej liczebność bakterii wskaźnikowych po 35 i 38 dniach zmniejszyła się z wartości 109 NPL·g-¹ do odpowiednio 104 i 103 NPL·g-¹. W nośnikach w warstwie dolnej nie uzyskano więc pełnej higienizacji biomasy.Due to the presence of dangerous chemical compounds and pathogenic microorganisms in crude sewage sludge, it must be subjected to pre-treatment. Application of improperly sanitized sewage sludge in agriculture poses a threat to people and animal's health. The aim of the study was to perform microbiological assessment of the effectiveness of sewage sludge composting together with wastes from municipal greens in the container technology based on the inactivation rate of faecal streptococci. The experiment was carried out in three cycles - in spring, summer and autumn periods. Indicator bacteria were introduced into composted material in the form of carriers. In the course of composting the total elimination of faecal streptococci was found in carriers from the top and middle layers of the biomass in all cycles. Theoretical time of bacterial survival ranged from 19 to 49 days. In summer and autumn, however, after 35 and 38 days the number of indicator bacteria in carriers from the bottom part decreased from 109 MPN·g-¹ to 104 and 10³, respectively. Thus, the complete biomass sanitization was not obtained in carriers in the bottom layer

Composting and anaerobic digestion technologies as methods for reduction of virus transmission in the environment

Survival of bovine enterovirus was studied in animal by-products subjected to sanitization processes. Composting technology and anaerobic digestion under mesophilic (37 °C) and thermophilic (55 °C) conditions were tested in terms of their effectiveness. Viruses were introduced into the biomass in the course of waste treatment processes and virus titres were determined at appropriate time intervals. Technology which allowed the most effective virus elimination, after 2 h, was thermophilic fermentation. During composting, bovine enterovirus survival ranged from 12 to 17 days, whereas the survival time for mesophilic fermentation was 28 days

Ocena mikrobiologiczna osadow sciekowych z zakladow miesnych

Źródłem zanieczyszczeń środowiska naturalnego jest przemysł spożywczy, w tym także zakłady mięsne. W osadach ściekowych pochodzących z rzeźni zagrożenie stanowią chorobotwórcze bakterie, wirusy i jaja pasożytów. Celem badań była ocena mikrobiologiczna surowych i kondycjonowanych wapnem osadów posedymantacyjnych i poflotacyjnych z mechaniczno-chemicznej oczyszczalni zakładów mięsnych. W okresie 11 miesięcy badano metodą płytkową ogólną liczbę bakterii, zaś metodą najbardziej prawdopodobnej liczby (NPL) liczbę E. coli i pałeczek Salmonella w osadzie. W osadzie posedymentacyjnym ogólna liczba bakterii wahała się w zakresie od 4,6 X 10⁷ do 1,6 x 10⁹ jtk·g⁻¹ osadu; w osadzie poflotacyjnym podobnie: od 5,6 x 10⁷ do 4,4 x 10⁹ jtk·g⁻¹ osadu. Miano coli badanych osadów wahało się w granicach od 10⁻⁵ do l0⁻⁷. Niepokojący był fakt wykrywania w badanych osadach pałeczek z rodzaju Salmonella. Liczba pałeczek Salmonella w obu osadach wahała się w zakresie od 1,5 x 10⁻¹ do 0,4 x 10⁰ jtk·g⁻¹. Po 24-godzinnym odkażaniu osadów wapnem palonym lub chlorowanym w mieszaninie osadowo-wapniennej nie wykrywano bakterii E. coli i Salmonella. Wyniki wskazują, że zastosowana w zakładach mięsnych technologia oczyszczania ścieków nie zapewnia dostatecznej higienizacji osadów. Stąd celowe wydaje się zastosowanie tlenku wapnia, jako środka kondycjonującego osady powstające w procesie mechaniczno-chemicznego oczyszczania ścieków.Food processing industry, including meat processing plants, are the source of natural environment pollution. The slaughterhouse sewage sludge with its pathogenic bacteria, viruses and parasite eggs makes a real threat. The present research aimed at microbiological analysis of raw and lime- conditioned post-sedimentation and post-flotation sludge obtained from mechanical and chemical sewage treatment at a meat processing plant. Over 11 months the dish method was applied to determine total number of bacteria, while the most probably number (MPN) method for the numbers of E. coli and Salmonella bacilli in the sludge. In post-sedimentation sludge the total number of bacteria ranged from 4.6 x 10⁷ to 1.6 x 10⁹ cfu·g⁻¹ sludge, whereas in the post-flotation sludge it ranged from 5.6 x 10⁷ to 4.4 x 10⁹ cfu·g⁻¹ sludge. The coli titre in tested sludge ranged within 10⁻⁵-l0⁻⁷. Unfortunately, there were also found some Salmonella bacilli. The number of Salmonella bacilli in both sludge samples ranged from 1.5 x 10⁻¹ to 0.4 x 10⁰ cfu·g⁻¹. After 24-hour sludge disinfection with quicklime or chlorinated lime, neither E. coli bacteria nor Salmonella were observed in the sludge or sludge-lime mixture. The results showed that the sewage treatment technology applied by meat processing plant did not ensure sufficient sludge treatment. Therefore it seems justifiable to apply the calcium monoxide to condition the sludge produced in the process of mechanical and chemical sewage treatment

Survival rate of Suid Herpesvirus (SuHV-1, Aujeszky`s disease virus, ADV) in composted sewage sludge

Sewage sludge constitutes a source of valuable biogenic raw materials, but it is a carrier of many pathogenic microorganisms and viruses. Subjected to an effective sanitization by means of the process of composting, it is suitable to use in agriculture as fertilizers. The aim of this study was to observe the survival rate of Suid Herpesvirus under the influence of the temperature alone (water bath) as well as in sewage sludge subjected to the process of composting (pile). The samples were taken at different time intervals, and the virus titres were determined. The viruses survived considerably longer under laboratory conditions: at 30°C as long as 21 days, at 40°C - 93 hours, and at 50°C - less than an hour. In the compost pile, in spite of the lack of the thermophylic phase, the total survival time of the viruses ranged from 34 to 44.5 hours, which indicates the vast importance of other physicochemical factors, apart from the temperature, contributing to virus inactivation

Survival of BPV and Aujeszky's disease viruses in meat wastes subjected to different sanitization processes

The effect of composting and anaerobic fermentations under meso- and thermophylic conditions (37° and 55℃) on the survival of bovine parvovirus (BPV) and Aujeszky’s disease viruse (ADV) in meat wastes has been examined in this study. Viruses were adsorbed on filters and introduced into carriers which were made of meat fragments of different sizes and bones or in the form of suspension they were introduced into the biomass in the course of processes of waste treatment. Carriers were removed at appropriate time intervals and virus titres were determined. The thermoresistant parvovirus survived for the longest time during mesophylic fermentation (almost 70 days), slightly shorter during composting (7-9.5 days depending on the type of carrier) and for the shortest time – at 55℃ (46-76 hours). Its inactivation rate was the fastest in a suspension, slower in meat and bone carriers. ADV inactivation proceeded considerably faster, as compared with BPV. Its active particles were not detected as early as in the 30th minute of thermophylic fermentation, the 6th hour of mesophylic fermentation and at the first sampling time during composting (at the 72nd hour). Total survival time ranged from 50 min to 13 hours. All the tested technologies enabled the effective elimination of ADV and on average twofold decrease in BPV titre. From the study conducted it follows that of both viruses, the BPV should be applied for validation processes of methods used in meat waste processing, particularly if this refers to methods where higher temperature is the factor inactivating pathogens

Enzymatic and antagonistic properties of fluorescent pseudomonas bacilli isolated from flax rhizoplane

W pracy zbadano stopień aktywności enzymów pektynolitycznych, celulolitycznych, amylolitycznych i proteolitycznych, a także zdolność do uruchamiania nierozpuszczalnych fosforanów przez fluoryzujące pałeczki z rodzaju Pseudomonas. Bakterie wyizolowano z ryzoplany lnu włóknistego, uprawianego w systemie zmianowania i monokultury. Żaden z izolatów nie wykazywał aktywności enzymatycznej wobec celulozy, natomiast pozostałe wielocukry hydrolizowane były przez wszystkie izolaty. Bakterie były najbardziej aktywne wobec białka. Oceniono również ich właściwości antagonistyczne względem wybranych patogenów grzybowych wyizolowanych z tego samego środowiska. Wszystkie z nich, chociaż w różnym stopniu, hamowały rozwój grzybów.The degree of pectinolytic, celulolytic, amylolytic and proteolytic enzymes activity as well as the ability to set in motion insoluble phosphates by the fluorescent bacilli of the genus Pseudomonas were evaluated. The bacteria were isolated from the rhizoplane of flax (Linum usitatissimum L.) grown in crop rotation and monoculture. None of the Pseudomonas isolates showed the enzymatic activity towards cellulose, while the other polysaccharides were hydrolyzed by all of them. Bacteria were most active towards protein. Their antagonistic properties towards selected pathogenic fungi isolated from the same environment were also evaluated. Isolates of the genus Pseudomonas were tested towards selected fungal pathogens. All of them inhibited the development of fungi, though to different extent

Effects of spring season solar drying process on sanitation indicators in sewage sludge and potential as a method for fertilizer production

The agricultural use of sewage sludge is possible on condition of maintaining microbiological and parasitological standards, and one of the most modern methods improving its sanitary state is solar drying. In the presented study, the effect of this process on the elimination of indicator microorganisms (Escherichia coli, Salmonella Senftenberg W775, Enterococcus spp.) and eggs of Ascaris suum introduced into the biomass of sludge was examined. The experiment was carried out in the spring period with a maximal temperature of 18 °C inside the drying plant. Bacteria and parasite eggs were introduced into special carriers (cylinders filled with sewage sludge) and placed at selected points of the drier. The carriers were removed every 7 days and subject to a research procedure in order to estimate the number of bacteria and percentage of live eggs of Ascaris suum. Sanitization of the material was not obtained, since after 28 days of the process the final product contained a large concentration of Enterococcus spp. and S. Senftenberg W775 (105-109 MPNg-1). Only the number of E. coli decreased by 6 log. During the process, the fastest decrease in the number of bacteria was observed in E. coli (ca 0.2 log/day), slower in enterococci (0.02-0.081 log/day), and the slowest in bacilli of the genus Salmonella (0.011-0.061 log/day). Sludge after drying also still contained 57-66% of live eggs of A. suum. The study proved that the solar drying of sludge in the spring period results in a product which poses a hazard for public and animal health and environmental sustainability, and should not be used as a fertilizer