The concern of a Cryptosporidium or Giardia waterborne outbreak due to treated wastewater has had water treatment utilities using some of the highest water cleansing technologies available. Cryptosporidiosis and Giardiasis are severe diarrheal diseases which can lead to death, thus it is important that appropriate steps are taken to assure these parasites are not present in the effluent of treated wastewater. This study examined the results of 863 assays for Giardia and Cryptosporidium on the effluent of wastewater treatment facilities and found that county of collection, watershed of collection, and laboratory analyzing the sample have the most significant impact on the detection of Cryptosporidium oocysts and Giardia cysts in wastewater effluent and that there were minimal but significant differences in method of treatment and method of filtration. To date no other comprehensive analysis of this data has been done.

Biogas is becoming a more important source of green, renewable energy however, its production results in a liquid wastewater, known as centrate, which must be treated due to its high levels of total dissolved solids (TDS), and chemical oxygen demand (COD). Currently, biogas generation facilities treat centrate using a combination of biological and physical treatments (via a membrane bioreactor (MBR)), which produces a stream known as MBR permeate. While MBR permeate achieves improved quality, MBR usage has several challenges including difficulty of scaling biological processes, and handling capacity limitations. In this study, membrane only treatment of centrate, collected from an operating biogas generation facility, was investigated to determine if similar quality permeates could be obtained without any biological treatments. Single- stage treatment of centrate using either polymeric or ceramic nanofiltration membranes with molecular weight cut offs between 400 and 800 Da, produced a permeate similar to MBR permeate. These membrane types caused average COD rejections of 92% and 90% respectively. However, the permeates from the nanofiltration membranes had very high levels of ammonia, which was not present in the MBR permeate. The ceramic nanofiltration membranes can achieve higher permeate fluxes than the polymeric nanofiltration membranes. Both membrane types experienced significant fouling which was removed using cleaning procedures. Two-stage treatment of centrate using ceramic nanofiltration membranes followed by polymeric reverse osmosis membranes further improved the quality of permeate and achieved COD rejections of 99% overall. While the reverse osmosis membranes did remove some ammonia, the levels were still higher than what was seen in the MBR permeate. The two-stage treatment of centrate can provide the permeate which is closest to the MBR permeate however, further studies are required to address the higher ammonia concentration values. The research shows that only using membranes is a potential treatment pathway for real centrate samples. / Thesis / Master of Applied Science (MASc) / The production of biogas, which is a green, renewable energy source results in a liquid wastewater known as centrate. This wastewater is very dirty and complex and requires treatment as it cannot be dumped and disposed of in its current state. Current treatment methods for centrate use combinations of biological treatment and filtration processes, which has its own challenges due to the complexity of biological treatments. An alternative treatment method for the centrate is nanofiltration membranes which offer the ability to treat large volumes of centrate wastewater without the complexity of relying on biological treatment options. Four different nanofiltration membranes, including two polymeric and two ceramic membranes, were used to treat real industrial wastewater samples of centrate collected from a biogas generation facility. Both types of nanofiltration membranes provided similar quality permeate to the current treatment method of centrate, which uses a combination of biological and physical treatment methods.