The detection of Entamoeba histolytica and Toxoplasma gondii in wastewater

To increase current knowledge on the epidemiology of protozoan parasites in wastewater treatment plants (WWTP), the occurrence of Entamoeba histolytica and Toxoplasma gondii in raw and treated wastewater was investigated. Samples were collected from WWTP twice a month over a period of 8 months. Determination of protozoa was performed using polymerase chain reaction (PCR) and light microscopy. After concentration and purification of wastewater samples, DNA extraction was conducted followed by PCR amplification of small subunit ribosomal RNA (SSU rRNA) gene sequences of E. histolytica and B1 gene of T. gondii. Loop-Mediated Isothermal Amplification (LAMP) primer set was designed from E. histolytica hemolysin gene HLY6. Amplification of DNA in the LAMP mixture was monitored by naked eye as a blue color solution after addition of, hydroxynaphthol blue (HNB) to the reaction tube. Light microscopy revealed the presence of Entamoeba in all raw wastewater samples and treated water samples. PCR amplification of DNA products revealed that all, (9/9) wastewater samples were positive for Entamoeba. None was positive for Toxoplasma. These findings, which corroborate recent observations, indicate that E. histolytica may pose a public health risk.

Microbial pathogens in wastewater treatment plants (WWTP) in Hamburg

Microbial pathogens are among the major health problems associated with water and wastewater. Classical indicators of fecal contamination include total coliforms, Escherichia coli, and Clostridium perfringens. These fecal indicators were monitored in order to obtain information regarding their evolution during wastewater treatment processes. Helminth eggs survive for a long duration in the environment and have a high potential for waterborne transmission, making them reliable contaminant indicators. A large quantity of helminth eggs was detected in the wastewater samples using the Bailanger method. Eggs were found in the influent and effluent with average concentration ranging from 11 to 50 eggs/L. Both E. coli and total coliforms concentrations were significantly 1- to 3-fold higher in influent than in effluent. The average concentrations of E. coli ranged from 2.5×10(3) to 4.4×10(5) colony-forming units (CFU)/100 ml. Concentrations of total coliforms ranged from 3.6×10(3) to 7.9×10(5) CFU/100 ml. Clostridium perfringens was also detected in influent and effluent of wastewater treatment plants (WWTP) at average concentrations ranging from 5.4×10(2) to 9.1×10(2) most probable number (MPN)/100 ml. Significant Spearman rank correlations were found between helminth eggs and microbial indicators (total coliform, E. coli, and C. perfringens) in the WWTP. There is therefore need for additional microbial pathogen monitoring in the WWTP to minimize public health risk.

The detection of Giardia cysts in a large-scale wastewater treatment plant in Hamburg, Germany

Giardia is one of the most common human enteric parasites that continue to be a major cause of diarrheal disease globally. Wastewater is an important source of Giardia transmission, and control of the pathogen by appropriate treatment of wastewater would limit its transmission. In this study the occurrence of Giardia cysts at various stages of the wastewater treatment plants was monitored for a period of 18 mo. Using immunomagnetic separation and immunofluorescence with monoclonal antibodies, cysts were detected in all samples throughout the sampling period at a concentration ranging from 50 to 7548 cysts/L. The overall removal efficiency of the cysts in the treatment plants was 78%. Seasonal analyses of results revealed that the pathogens (cysts) were most prevalent in influents and effluents during autumn and winter.

Occurrence of Cryptosporidium in a wastewater treatment plant in North Germany

Cryptosporidium parvum is one of the most common human parasitic protozoa and is responsible for many waterborne outbreaks in several industrialized countries. The oocyst, which is the infective form, is known to be highly resistant to wastewater treatment procedures and represents a potential hazard to human populations through contaminated raw or treated wastewater. In this investigation, the occurrence of Cryptosporidium in wastewater samples was monitored and removal efficiency was assessed. Treated (effluent) and untreated (influent) wastewater samples were collected seasonally over a period of 2 years. Oocysts were repeatedly detected in influent and effluent samples collected from the treatment plant during all sampling seasons, with a mean concentration of 782 oocysts/L. The seasonal distribution showed that oocysts are predominant during autumn and winter. Molecular analyses via the small (18S) subunit of rRNA amplification and subsequent sequencing with an objective of characterizing the oocysts revealed that Cryptosporidium parvum was the dominant Cryptosporidium parasite present in wastewater.

Terra Preta sanitation: re-discovered from an ancient Amazonian civilisation - integrating sanitation, bio-waste management and agriculture

The recent discovery of the bio-waste and excreta treatment of a former civilisation in the Amazon reveals the possibility of a highly efficient and simple sanitation system. With the end product that was black soil they converted 10% of former infertile soil of the region: Terra Preta do Indio (black soil of the Indians). These soils are still very fertile 500 years after this civilisation had disappeared. Deriving from these concepts, Terra Preta Sanitation (TPS) has been re-developed and adopted. TPS includes urine diversion, addition of a charcoal mixture and is based on lactic-acid-fermentation with subsequent vermicomposting. No water, ventilation or external energy is required. Natural formation processes are employed to transform excreta into lasting fertile soil that can be utilised in urban agriculture. The authors studied the lacto-fermentation of faecal matter with a minimum of 4 weeks followed by vermicomposting. The results showed that lactic-acid fermentation with addition of a charcoal mixture is a suitable option for dry toilets as the container can be closed after usage. Hardly any odour occured even after periods of several weeks. Lactic-acid fermentation alone without addition of bulking agents such as paper and sliced-cut wood to raise the C/N ratio is creating a substrate that is not accepted by worms.