City's Treatment Plant Research Articles

Chlorella vulgaris in wastewater treatment processes – practical experience

Wastewater from human settlements contains a significant amount of organic and biogenic substances. Insufficiently treated wastewater enters surface water and leads to their eutrophication. The usage of microalgae in wastewater treatment has significant advantages in comparison with other methods of removing biogenic substances. Namely: effective and simultaneous removal of nitrogen and phosphorus without reagents management facilities, oxygen formation. Using microalgae in wastewater treatment is a new environmentally friendly biotechnological method. Microalgae grow well in wastewater, from which they absorb pollutants. The purpose of the study is to analyze the work and determine the possibility of intensification of sewage treatment plants in the western region of Ukraine with a population of about 18,900 inhabitants. Productivity of treatment plant is 3400 m3/day. Experimental investigation consisted in adding a concentrate of a living microalgae strain of the species Chlorella vulgaris to the wastewater that was entered to the treatment plant during May-September 2019. During the research, the results of wastewater analyzes conducted by the chemical laboratory of the municipal water supply and sewerage company were used. The results of the survey and analysis of the city's treatment plant indicate an insufficient degree of wastewater treatment. The effectiveness of Chlorella vulgaris at the treatment plant has been experimentally proven. Mathematical dependences of the effect of wastewater treatment (using Chlorella vulgaris) on their temperature according to the indicators: BOD5, COD, concentration of ammonium nitrogen, phosphates and suspended solids were obtained. Dependencies are described by a linear function that characterizes the general behavior of the obtained data. The obtained results made it possible to significantly reduce the negative impact of treatment plants on the environment.

An update on San Francisco's wastewater master planning process and implementation

The City and County of San Francisco embarked on a 30 year master planning process in part prompted by public concerns over environmental justice related to the neighborhood impacts of the Southeast Water Pollution Control Plant. The Sewer System Master Plan, as it is called, developed a long term Integrated Watershed Management Plan for the City's treatment plants and collection system. This paper will focus on the planning framework and public input to the process and how the master plan of 2009 evolved into the current implementation plan, the Sewer System Improvement Program. The paper describes the public process and public concerns; and compares the master plan project recommendations with the implementation projects.

San Francisco's Vision for the Future: An Integrated Urban Wastewater Management Plan

The City and County of San Francisco (“City”) embarked upon a 30-year master planning process in part prompted by public concerns related to the neighbourhood impacts of the Southeast Water Pollution Control Plant (SEP). The Sewer System Master Plan, as it is called, developed a long term Integrated Urban Watershed Management Plan for the City's treatment plants and collection system. This paper focuses on the planning framework and public input to the process, particularly as it relates to proposed changes to the SEP. The resulting improvements address issues of replacing aging infrastructure, eliminating odor emissions, and visually screening the treatment plants that are situated within an urban setting. The recommended project addresses the needed repair of the existing infrastructure; and proposes that the City move towards an integrated urban watershed approach, initially through localized rainwater harvesting and opportunistic water reclamation.

Groundwater Under the Influence: What to Do When Process Changes Cause Turbidity Problems

Sioux City, Iowa, obtains a large percentage of its drinking water supply from a horizontal collector well and 12 vertical wells adjacent to the Missouri River. Because the water supply is classified as groundwater under the direct influence of surface water, the city was required in the late 1990s to expand its treatment process to deal with potential surface water contaminants. After constructing a chlorine contact chamber to improve the disinfection contact time and replacing filter media to lower iron and manganese levels, the city's treatment plant experienced elevated, fluctuating turbidity levels and manganese oxidation after filtration. The treatment problems led to treatment technique violations, and the city had to conduct an extensive investigation into what caused the problems. After many parameters were investigated, the elevated turbidity levels were attributed to manganese oxidation after filtration, new filter media, and increased contact time. This article discusses the investigation, causes, and the operational changes implemented to control manganese oxidation and turbidity levels.

PERFORMANCE OF A NEW POLYMERIC WATER DISINFECTANT1

ABSTRACT: A new insoluble N‐halamine polymeric disinfectant material has been tested in a water filter application to determine (1) its tendencies to leach undesirable decomposition products, (2) its range of potential applicability, and (3) its regenerability. In flowing water tests, poly‐1,3‐dichloro‐5‐methyl‐5‐(4‘‐vinylphenyl)hydantoin (Poly‐I) leached only small amounts of total organic carbon, free and total chlorine, anions, and volatile organics such as trihalomethanes. Furthermore, Poly‐I provided bactericidal efficacy over the pH range 4.5 to 9.5 and at temperatures as high as 37°C. Poly‐I is deactivated by reducing agents such as sodium thiosulfate and by ethanol; following deactivation, it can be regenerated by exposure to flowing aqueous free chlorine. Poly‐I appears suitable for use as a biocidal filter for small potable and recreational waters, for it is effective over a wide pH and temperature range and is readily regenerable. It would not be useful, however, for disinfection of large bodies of water such as in city treatment plants because of its cost and the large amount of the material that would be necessary.