scholarly journals Removal of Cryptosporidium by wastewater treatment processes: a review

2015 ◽  
Vol 14 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Abidelfatah M. Nasser
Keyword(s):  
Animal Species ◽  
Protozoan Parasite ◽  
High Rate ◽  
Environmental Stability ◽  
Infectious Dose ◽  
Chlorine Disinfection ◽  
Untreated Wastewater ◽  
Treatment Processes ◽  
Cryptosporidium Oocysts ◽  
Suitable Treatment

Cryptosporidium is a protozoan parasite that infects humans and various animal species. The environmental stability and the low infectious dose of Cryptosporidium facilitate its transmission by water and food. Discharge of untreated wastewater may result in waterborne or foodborne Cryptosporidium outbreaks, therefore a suitable treatment may prevent its dissemination. Most studies on the prevalence of Cryptosporidium oocysts in wastewater have reported a concentration range between 10 and 200 oocysts/L and a prevalence of 6 to 100%. Activated sludge has been found to be ineffective for the removal of Cryptosporidium oocysts. Stabilization ponds and constructed wetlands are efficient for the reduction of Cryptosporidium from wastewater, especially when the retention time is longer than 20 days at suitable sunlight and temperature. High rate filtration and chlorine disinfection are inefficient for the reduction of Cryptosporidium from effluents, whereas ultrafiltration and UV irradiation were found to be very efficient for the reduction of Cryptosporidium oocysts. Adequate tertiary treatment may result in high quality effluent with low risk of Cryptosporidium for unrestricted irrigation and other non-potable applications.

Protozoan predation as a mechanism for the removal of cryptosporidium oocysts from wastewaters in constructed wetlands

2001 ◽  
Vol 44 (11-12) ◽  
pp. 191-198 ◽  
Author(s):  
R. Stott ◽  
E. May ◽  
E. Matsushita ◽  
A. Warren
Keyword(s):  
Constructed Wetlands ◽  
Protozoan Parasite ◽  
Epifluorescence Microscopy ◽  
Free Living ◽  
Feeding Experiments ◽  
Treatment Processes ◽  
Ciliate Species ◽  
Cryptosporidium Oocysts ◽  
The Uk ◽  
Stylonychia Mytilus

The removal of the protozoan parasite, Cryptosporidium parvum, from wastewaters is becoming of increasing importance in the UK, especially since contamination of raw waters by sewage effluents has been implicated in major waterborne outbreaks of cryptosporidiosis in recent years. Compared to conventional wastewater-treatment processes, constructed wetlands have demonstrated favourable removal rates for Cryptosporidium oocysts. The removal mechanisms, however, remain unknown. Predation by free-living ciliated protozoa, which are commonly found in constructed wetlands, was investigated as a possible mechanism for oocyst removal. In laboratory feeding experiments, ciliates (Euplotes patella, Stylonychia mytilus, Paramecium caudatum and an unidentified wetland ciliate species), were exposed to doses ranging from 10 to 106 oocysts/ml for between 5 and 60 minutes. Ciliate predatory activities were assessed by enumerating fluorescently labelled ingested oocysts using epifluorescence microscopy. Oocysts were found to be ingested by all species investigated. Paramecium demonstrated the highest mean ingestion rates (up to 170 oocysts/hr) followed by Stylonychia (up to 60 oocysts/hour). Euplotes and the wetland ciliate had lower mean grazing rates (4 and 10 oocysts/hr respectively). These results indicate that protozoan predation may be an important factor in the removal of Cryptosporidium oocysts from wastewaters in constructed wetlands.

scholarly journals Occurrence of SARS-CoV-2 RNA in Six Municipal Wastewater Treatment Plants at the Early Stage of COVID-19 Pandemic in The United States

Pathogens ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 798
Author(s):  
Samendra P. Sherchan ◽  
Shalina Shahin ◽  
Jeenal Patel ◽  
Lauren M. Ward ◽  
Sarmila Tandukar ◽  
...  
Keyword(s):  
United States ◽  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Quantitative Polymerase Chain Reaction ◽  
The United States ◽  
Secondary Effluent ◽  
Untreated Wastewater ◽  
Treatment Processes ◽  
Wastewater Samples

In this study, we investigated the occurrence of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) RNA in primary influent (n = 42), secondary effluent (n = 24) and tertiary treated effluent (n = 34) collected from six wastewater treatment plants (WWTPs A–F) in Virginia (WWTP A), Florida (WWTPs B, C, and D), and Georgia (WWTPs E and F) in the United States during April–July 2020. Of the 100 wastewater samples analyzed, eight (19%) untreated wastewater samples collected from the primary influents contained SARS-CoV-2 RNA as measured by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) assays. SARS-CoV-2 RNA were detected in influent wastewater samples collected from WWTP A (Virginia), WWTPs E and F (Georgia) and WWTP D (Florida). Secondary and tertiary effluent samples were not positive for SARS-CoV-2 RNA indicating the treatment processes in these WWTPs potentially removed SARS-CoV-2 RNA during the secondary and tertiary treatment processes. However, further studies are needed to understand the log removal values (LRVs) and transmission risks of SARS-CoV-2 RNA through analyzing wastewater samples from a wider range of WWTPs.

Evaluation of flocculation and dissolved air flotation as an advanced wastewater treatment

2001 ◽  
Vol 43 (8) ◽  
pp. 83-90 ◽  
Author(s):  
A. C. Pinto Filho ◽  
C. C. Brandão
Keyword(s):  
Wastewater Treatment ◽  
Domestic Wastewater ◽  
High Rate ◽  
Advanced Treatment ◽  
Dissolved Air Flotation ◽  
Anaerobic Reactor ◽  
Treatment Processes ◽  
Domestic Wastewater Treatment ◽  
Air Flotation ◽  
Dissolved Air

A bench scale study was carried out in order to evaluate the applicability of dissolved air flotation (DAF) as an advanced treatment for effluents from three different domestic wastewater treatment processes, namely: (i) a tertiary activated sludge plant ; (ii) an upflow sludge blanket anaerobic reactor (UASB); and (iii) a high-rate stabilization pond.

Modeling Mass Transfer in Biological Wastewater Treatment Processes

1986 ◽  
Vol 18 (6) ◽  
pp. 35-45 ◽  
Author(s):  
John C. Kissel
Keyword(s):  
Mass Transfer ◽  
Computer Simulation ◽  
Wastewater Treatment ◽  
Biological Treatment ◽  
Process Models ◽  
High Rate ◽  
Biological Wastewater Treatment ◽  
Trickling Filter ◽  
Treatment Processes ◽  
Individual Effects

Parameters characterizing intrasolid, liquid/solid, and gas/liquid mass transport phenomena in biological treatment systems are required if mass transfer is to be included in process models. Estimates of such parameters are presented and discussed. Collective and individual effects of mass transfer resistances are illustrated by computer simulation of a high-rate trickling filter.

Intelligent control system based on blackboard concept for wastewater treatment processes

1998 ◽  
Vol 37 (12) ◽  
pp. 77-85 ◽  
Author(s):  
T. Ohtsuki ◽  
T. Kawazoe ◽  
T. Masui
Keyword(s):  
Wastewater Treatment ◽  
Control System ◽  
Activated Sludge ◽  
Intelligent Control ◽  
Software Agents ◽  
High Rate ◽  
Target System ◽  
Activated Sludge Process ◽  
Intelligent Control System ◽  
Treatment Processes

An intelligent control system for wastewater treatment processes has been developed and applied to fullscale, high-rate, activated sludge process control. In this control system, multiple software agents that model the target system using their own modeling method collaborate by using data stored in an abstracted database named ‘blackboard’. The software agents, which are called ‘expert modules’, include a fuzzy expert system, a fuzzy controller, a theoretical activated sludge model, and evaluators of raw data acquired by various online sensors including a respirometer. In this paper, the difficulties of controlling an activated sludge system by using a single conventional strategy are briefly reviewed, then our approach to overcome these difficulties by using multiple modeling methods in the framework of an ‘intelligent control system’ is proposed. Case studies of applications to a high-rate activated sludge process that treats BOD and nitrogen of human excrement are also presented.

scholarly journals Cryptosporidium spp. Infections in Livestock and Wild Animals in Azerbaijan Territory

2020 ◽  
Vol 2 (1) ◽  
pp. 44
Author(s):  
Simuzer Mamedova ◽  
Panagiotis Karanis
Keyword(s):  
Staining Method ◽  
Current Knowledge ◽  
Protozoan Parasite ◽  
Structural Features ◽  
Cryptosporidium Spp ◽  
Faecal Samples ◽  
Cryptosporidium Oocysts ◽  
Stool Specimens ◽  
Intracellular Protozoan Parasite ◽  
Acid Fast Staining

Cryptosporidium is an intracellular protozoan parasite and is increasingly gaining attention as a human and an animal pathogen, mainly due to its predominant involvement in worldwide waterborne outbreaks. This paper reviews the current knowledge and understanding of Cryptosporidium spp. in terrestrial and aquatic animals in Azerbaijan. The diagnosis of cryptosporidiosis relies on the identification of oocysts in faecal samples released by the infected host. Stool specimens were processed using the modified acid-fast staining method (Ziehl-Neelsen) and microscopically examined for Cryptosporidium oocysts. Thirteen species of Cryptosporidium (C. fragile, C. ducismarci, C. serpentis, C. varani, C. baileyi, C. meleagridis, C. muris, C. parvum, C. ubiquitum, C. andersoni, C. bovis, C. hominis, C. suis) from amphibians, reptiles, birds and mammals have been identified as a result of studies conducted between 1987 and 2019 on the structural features of Cryptosporidium oocysts in Azerbaijan territory.

Water Quality Management in the Chemical Industry – BASF's Ludwigshafen Complex as an Example – Investigations, Design, Operation

1984 ◽  
Vol 16 (12) ◽  
pp. 583-607
Author(s):  
H Engelhardt ◽  
W G Haltrich ◽  
W Weisbrodt
Keyword(s):  
Water Quality Management ◽  
Treatment Plant ◽  
High Rate ◽  
Halogenated Hydrocarbons ◽  
Volume Index ◽  
Treatment Procedure ◽  
Metal Compounds ◽  
Suitable Treatment ◽  
Treatment Facilities ◽  
Waste Water Management

The BASF works Ludwigshafen - the largest integrated chemical complex in Europe - via re-organization of its waste water management (installation of a separate sewerage system, intra-plant measures, central chemical-mechanical-biological treatment plant) has achieved a reduction of the substance load discharged to the Rhine by ca. 98% in terms of BOD5 and by ca. 94% for COD and TOC. During many years (1961 - 1974) investigations have been carried out with pilot plants on laboratory scale (50l) as well as on semi-industrial scale (20 000 population equivalents) for selecting the suitable treatment procedure and dimensioning of the central treatment plant. The treatment procedure developed according to tests in the pilot plant (high-rate primary sedimentation to avoid activated sludge with poor settling properties, followed by an aeration stage in form of a circular basin according to the carrousel system, including a denitrification zone of variable volume) has proven successful in practice. The sludge volume index is 50 ml/g. In spite of varying nitrate concentrations the denitrification is working without problems. In the central treatment plant (dimensioning data 375 000 kg/d BOD5, ca. 100 000 kg/d NO3−, DWF 660 000 m3/d) BOD5 is degraded by 96%, COD as well as TOC by ca. 80 - 85%, while nitrate is eliminated by 95 %. It will be reported mainly on the operation experience. In addition to the central treatment facilities there are numerous decentralized measures in regard to the treatment of concentrated waste waters or waters containing poorly degradable substances like halogenated hydrocarbons and heavy metal-compounds.

scholarly journals Innovative Biological Treatment Processes for Wastewater in Canada

2003 ◽  
Vol 38 (2) ◽  
pp. 243-265 ◽  
Author(s):  
Catherine N. Mulligan ◽  
Bernard F. Gibbs
Keyword(s):  
Biological Treatment ◽  
Waste Treatment ◽  
Oil Spills ◽  
Metal Removal ◽  
Oxygen Demand ◽  
High Rate ◽  
Future Research ◽  
New Developments ◽  
Treatment Processes ◽  
Stage Of Development

Abstract Biological treatment of wastewater has been employed successfully for many types of industries. Aerobic processes have been used extensively. Production of large amounts of sludge is the main problem and methods such as biofilters and membrane bioreactors are being developed to combat this phenomenon. Anaerobic waste treatment has undergone significant developments and is now reliable with low retention times. The UASB, the original high rate anaerobic reactor, is now becoming less popular than the EGSB reactor. New developments such as the Annamox process are highly promising for nitrogen removal. For metal removal, processes such as biosorption and biosurfactants combined with ultrafiltration membranes are under development. Biosurfactants have also shown promise as dispersing agents for oil spills. If space is available, wetlands can be used to reduce biological oxygen demand (BOD), total suspended solids (TSS), nutrients and heavy metals. These innovative processes are described in this paper in terms of applications, the stage of development, and future research needs particular to Canada.

scholarly journals Cryopreservation of boar semen

2020 ◽  
Vol 65 (No. 4) ◽  
pp. 115-123
Author(s):  
Marija Jovičić ◽  
Eva Chmelíková ◽  
Markéta Sedmíková
Keyword(s):  
Animal Species ◽  
Semen Quality ◽  
Egg Yolk ◽  
High Rate ◽  
Freezing And Thawing ◽  
Long Term Storage ◽  
Boar Semen ◽  
Boar Spermatozoa ◽  
Term Storage

Sperm cryopreservation is the best technology for long-term storage of the semen. However, the damage of boar spermatozoa by cryopreservation is more severe than in other animal species and a standardized freezing protocol for efficient cryopreservation has not been established yet. Semen quality and freezability vary greatly between breeds as well as between individual boars and even the season. Boar spermatozoa are sensitive to low temperatures; they sustain damage and a high rate of mortality and freezing/thawing the boar semen may strongly impair the sperm function and decrease the semen quality. The freezability of boar semen can be influenced by a cryopreservation procedure, and also by using various additives to freezing and thawing extenders such as antioxidants. In order to obtain acceptable results after thawing the boar semen, it is necessary to combine an optimal amount of additives (glycerol, egg yolk, sugars, antioxidants), cooling and warming velocities.

Sign in / Sign up

Export Citation Format

Share Document