Analysis of 10 years of virus monitoring data from Los Angeles County treatment plants meeting California wastewater reclamation criteria

Yanko, William A.

doi:10.2175/wer.65.3.5

Cited by 31 publications

(15 citation statements)

References 18 publications

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“…Greater than 98% of the filtered final effluent turbidity values are < 2.0 NTU and essentially all are <2.5 NTU. Furthermore, the disinfected ter tiary filter effluents have been found to be negative on enteric virus detection since the initiation of monthly effluent moni toring in 1982 (Yanko, 1993).…”

Section: Resultsmentioning

confidence: 99%

Evaluation of four different tertiary filtration plants for turbidity control

Kuo¹,

Chen²,

Stahl³

et al. 1994

Water Environment Research

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The County Sanitation Districts of Los Angeles County operate 10 water reclamation plants (WRPs) for wastewater reclamation and reuse. To comply with State of California's stringent wastewater reclamation criteria, tertiary filtration systems are required at seven of these WRPs. Four types of filters, including mono‐medium gravity (activated carbon or anthracite coal), dual‐media gravity, and dual‐media pressure filters, are used. A study has been conducted to evaluate and to compare the filters' performance. The study started with evaluating turbidity and suspended solids (SS) removal by using plant operational data. Ratios of SS to turbidity were determined and found comparable among the plants. Although all filters provide good turbidity control, removal efficiencies are different among the filtration systems. Some plausible explanations for the apparent differences in removal are provided. Particle size distribution (PSD) measurements were made on samples from various locations at the WRPs to provide insights into particle removal. Typical particle size and volume distributions in the wastewater streams were established. Although turbidity and PSD could not be well correlated, particle removals by the four filtration systems were determined for better understanding of their removal mechanisms.

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Section: Resultsmentioning

confidence: 99%

Evaluation of four different tertiary filtration plants for turbidity control

Kuo¹,

Chen²,

Stahl³

et al. 1994

Water Environment Research

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“…Reclaimed water produced by the CSDLAC is disinfected via chlorination and consistently meets CWRC. Through an extensive monitoring program, the CSDLAC have demonstrated that enteric viruses are effectively removed through secondary, tertiary, and chlorine treatment (Yanko, 1993). While UV irradiation holds great potential for wastewater disinfection, further work must be done to ensure that effective removal of a wide range of microorganisms can be achieved.…”

Section: Discussionmentioning

confidence: 99%

“…Of the 16 runs, 4 were devoted to sampling for the indigenous enteric viruses (IEVs) and 12 for the seeded poliovirus (SPV). During the indigenous enteric virus (IEV) experiments, 2 UV influent water samples (tertiary effluent) were collected using a truckmounted portable concentrator as previously described (Yanko, 1993). Four UV disinfected output samples (tertiary effluent) for the IEVs were collected into 760 L holding tanks and concentrated as described below.…”

Section: Large Volume Uv Effluent Sampling For Virus Isolationmentioning

confidence: 99%

Detection of Infectious Adenovirus in Tertiary Treated and Uv Disinfected Wastewater During a Uv Disinfection Pilot Study

Thompson¹,

James²,

Suva-Castillo³

et al. 2000

proc water environ fed

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A pilot study investigating the efficacy of low pressure, high intensity ultraviolet (UV) radiation for disinfection of urban wastewater was conducted. The pilot study utilized a small-scale version of the Ultra Guard UV treatment system provided by UV Systems Technology, Inc. (Burnaby, Canada). The primary objective was to determine whether low pressure, high intensity UV irradiation could potentially be used to meet the California Water Reclamation Criteria (CWRC) for total coliform bacteria in reclaimed water and to determine its potential for a 99.99% reduction of two model enteric viruses (MS2 coliphage and poliovirus). UV pilot unit inactivation of the total and fecal coliform bacteria, sewage indigenous F-specific coliphage, seeded F-specific coliphage (MS2), sewage indigenous enteric viruses, and seeded poliovirus type I in tertiary treated wastewater was investigated. During the course of the pilot study, an infectious adenovirus was isolated from UV disinfected tertiary and secondary treated wastewater. The virus was detected in 15 of 16 experiments involving large volume (352-697 L) sampling and analysis for indigenous enteric viruses and seeded poliovirus. The adenovirus was identified via electron microscopy and enzyme immunoassay after WEFTEC 2000 isolation using traditional cell culture based methods. Tertiary treated samples in which the adenovirus was detected received calculated UV doses in the range of 34-71 mWsec/cm 2 . Turbidity and total coliform bacteria levels in these samples were within the CWRC standards of <2 NTU and no greater than 23 MPN/100 mL for a single sample (30 d sampling period), respectively. Overall, total coliform bacteria were effectively removed from UV disinfected tertiary effluent indicating that low pressure, high intensity UV irradiation could potentially be used to meet the stringent CWRC. Seven-day total coliform median values were not determined from the pilot unit data, however, a conservative estimate suggests that a dose of approximately 60 mW-sec/cm 2 would be sufficient to meet the 7-d median concentration of no more than 2.2 MPN/100 mL for the last 7 samples taken. A 4-log 10 removal of seeded MS2 and indigenous F-specific coliphage in the pilot unit experiments (tertiary effluent) was achieved at doses of 70 and 50 mW-sec/cm 2 , respectively. The seeded poliovirus was not detected in UV treated secondary or tertiary effluents, however, problems with the concentration protocol prevented documentation of a specific 4-log 10 removal of the virus. Comparative collimated UV irradiation studies indicated that the isolated adenovirus was more UV resistant than MS2 coliphage and poliovirus type I. Doses of approximately 33, 112, and 183 mW-sec/cm 2 were required to achieve a 4-log 10 removal of poliovirus, MS2, and the isolated adenovirus, respectively. These findings indicate that UV doses found to be effective at meeting the stringent CWRC total coliform standards may not provide suitable reduction of some naturally occurring pathogenic viruses such as adenovirus...

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“…In addition, there is no consensus among public health experts regarding the health significance of low levels of viruses in reclaimed water. A significant body of information exists indicating that viruses are removed or inactivated to low or immeasurable levels via appropriate wastewater treatment, including filtration and disinfection [5,19,32].…”

Section: Water Quality Monitoringmentioning

confidence: 99%

Water Reclamation and Reuse Criteria

Crook¹

2004

Advances in Water and Wastewater Treatment

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Analysis of 10 years of virus monitoring data from Los Angeles County treatment plants meeting California wastewater reclamation criteria

Cited by 31 publications

References 18 publications

Evaluation of four different tertiary filtration plants for turbidity control

Evaluation of four different tertiary filtration plants for turbidity control

Detection of Infectious Adenovirus in Tertiary Treated and Uv Disinfected Wastewater During a Uv Disinfection Pilot Study

Water Reclamation and Reuse Criteria

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