Presentation Title

Evaluation of Bacterial Inactivation in Decentralized Wastewater Treatment System for Reuse Potential in California

Faculty Mentor

Monica Palomo

Start Date

18-11-2017 11:30 AM

End Date

18-11-2017 11:45 AM

Location

9-243

Session

Engineering/CS 1

Type of Presentation

Oral Talk

Subject Area

engineering_computer_science

Abstract

Decentralized wastewater treatment systems (DEWATS) are alternatives to traditional septic systems due to low maintenance costs, easy maintenance, can be linked to energy production, and be part of systems trains including for example wetlands or ponds to polish the water quality beyond what can be achieved in just a septic tank system. Moreover, DEWATS provide an opportunity to reuse water on site instead of allowing it to percolate it into the ground. Implementation of DEWATS in small rural, low income California communities that are not connected to a centralized wastewater treatment system would be beneficial since the wastewater from multiple homes can be treated and kept on site. This would provide opportunities for local water reuse for agricultural irrigation, site beautification and dust control. California’s Title 22 legislation has stringent and specific requirements for reclaimed water applications. DEWATS reclaimed effluent could be reused onsite as long as California Title 22 requirements are met. This study evaluates the microbial reduction and inactivation through a DEWATS located in Durban, South Africa. Log Inactivation in the DEWATS was determined to average .892 for coliform and .776 for E. Coli during the two weeks duration of the study. Thus, it does not meet the stringent California Title 22 log 5 inactivation. An additional process step such a horizontal and vertical flow wetland or retention pond would be needed and have been documented in other studies to reach the 5 log limits. Even further reduction will be achieved with coupled terminal UV disinfection. The criteria to meet the California Title 22 standards will in these circumstances even achieve a higher treatment efficiency than statued.

Summary of research results to be presented

DEWATS in Durban, South Africa water quality and assessment of suitability for reuse purposes in California.

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Nov 18th, 11:30 AM Nov 18th, 11:45 AM

Evaluation of Bacterial Inactivation in Decentralized Wastewater Treatment System for Reuse Potential in California

9-243

Decentralized wastewater treatment systems (DEWATS) are alternatives to traditional septic systems due to low maintenance costs, easy maintenance, can be linked to energy production, and be part of systems trains including for example wetlands or ponds to polish the water quality beyond what can be achieved in just a septic tank system. Moreover, DEWATS provide an opportunity to reuse water on site instead of allowing it to percolate it into the ground. Implementation of DEWATS in small rural, low income California communities that are not connected to a centralized wastewater treatment system would be beneficial since the wastewater from multiple homes can be treated and kept on site. This would provide opportunities for local water reuse for agricultural irrigation, site beautification and dust control. California’s Title 22 legislation has stringent and specific requirements for reclaimed water applications. DEWATS reclaimed effluent could be reused onsite as long as California Title 22 requirements are met. This study evaluates the microbial reduction and inactivation through a DEWATS located in Durban, South Africa. Log Inactivation in the DEWATS was determined to average .892 for coliform and .776 for E. Coli during the two weeks duration of the study. Thus, it does not meet the stringent California Title 22 log 5 inactivation. An additional process step such a horizontal and vertical flow wetland or retention pond would be needed and have been documented in other studies to reach the 5 log limits. Even further reduction will be achieved with coupled terminal UV disinfection. The criteria to meet the California Title 22 standards will in these circumstances even achieve a higher treatment efficiency than statued.