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Key Takeaways: Houston's Northeast Water Purification Plant expansion project is required to comply with subsidence district rules for conversion from groundwater to surface water supply. Innovative solutions for the expanded plant include two coagulation recipes to treat water from Lake Houston; treatment with chlorine dioxide, ozone, and biological filtration; and enhanced residuals treatment. A progressive design–build approach—used for the largest project of this kind presently underway in North America—maximized stakeholder involvement. [ABSTRACT FROM AUTHOR]

As preventive of possible environmental nuisances that can cause discharges water in nature, we undertook this study of the influence of salinity wastewater on the treatment efficiency of a biological filter consisting of dune sand. In this work, we designed six identical columns of filtration with sand from the same region of the N’Goussa city (located in the southeast of Algeria). The filters used are fed with wastewater at six different total salinity rates ranging from 0.065% to 0.265% corresponding to the electrical conductivity of 0.85 mS/cm to 3.5 mS/cm. This filtration efficiency was assessed by monitoring changes in the conductivity and the overall pH of the treated water and the chemical oxygen demand (COD). The results obtained showed that the change in the salinity of sewage water has a negative effect on the degradation of organic matter. Indeed, over the salt content is high, over the effectiveness of the biological treatment is reduced, suggesting in this type of case a prior desalination system and tests are under way in our laboratory. [ABSTRACT FROM AUTHOR]

Biofilters have gained in popularity for drinking water treatment for reasons that include reducing disinfectant demand, disinfection by-product formation, and regrowth in distribution systems. Adenosine triphosphate (ATP) detection is being used more frequently as an easy and rapid method to quantify viable biomass in biofilters; however, there is little information on the relationship of ATP levels to biofiltration parameters and performance. In this study, a comprehensive comparison of published ATP data was conducted, which found that concentrations at the top of active, acclimated biofilters typically were in the range of 102 to 103 ng ATP/cm3 media. The effect of various biofilter parameters (source water characteristics and quality, pretreatment, hydraulic loading rate, temperature, and sampling depth) on ATP levels is discussed and evaluated using published ATP data. The authors also assess the relationship between ATP and biofilter performance in terms of carbon removal and identify a need for further research in this area. [ABSTRACT FROM AUTHOR]

Removal of dissolved organic and inorganic contaminants is an anticipated benefit of the biofiltration of drinking water; however, common biofiltration design and operational practices do not seek to enhance the biological activities associated with those removals. A pilot-scale study identified two enhancement strategies-nutrient and peroxide dosing-that improved both water quality and hydraulic performance of a biofilter. These strategies control the formation of extracellular polymeric substances (a potential foulant of biological filters) while maintaining or increasing microbial activity. Biofilter nutrient enhancement was found to decrease terminal head loss by ∼ 15% relative to a control filter with no nutrient enhancement. Nutrient enhancement also sustainably decreased breakthrough of 2-methylisoborneol (MIB), manganese (Mn), and dissolved organic carbon (DOC). Peroxide enhancement was performed to increase oxidative action of biofilter microorganisms and promote the oxidation of inactive biomass. Peroxide enhancement decreased terminal head loss up to ∼ 60% relative to the control filter, while maintaining MIB, Mn, and DOC treatment performance. This case study is an important step in moving the practice of biofiltration from a passive process to a purposefully operated biological system, i.e., engineered biofiltration [ABSTRACT FROM AUTHOR]

During the past 12 years, six small water treatment systems in Western Canada have used biological filtration as a pretreatment process for reverse osmosis membranes. INSET: EXPLORING PRETREATIVIENT OPTIONS IN YELLOW QUILL F. [ABSTRACT FROM AUTHOR]

Continuous organic characterization at a full‐scale drinking water treatment plant was achieved using fluorescence spectroscopy. The feasibility of this method was demonstrated through monitoring the performance of biological activated carbon contactors (BACCs), which serve as pretreatment for fouling control of ultrafiltration (UF) membranes. Fluorescence monitoring was applied successfully to identify the preferential removal of select fluorescence components and addition of another microbial humic‐like component by the biological filters. Spikes in BACC influent organic matter and fouling development on the downstream UF membranes highlighted the importance of preozonation. To demonstrate possible use of the short‐term continuous fluorescence data, neural networks were used to predict fouling development on downstream UF on the basis of BACC effluent water quality. Short‐term fluctuations in fouling development were well predicted by incorporation of continuous fluorescence characterization data. Continuous organic characterization shows promise for the application of fluorescence spectroscopy for real‐time process optimization and control in drinking water treatment systems. [ABSTRACT FROM AUTHOR]

Biofiltration, a reliable process that has been used to purify water for hundreds of years, can address a wide array of regulated and emerging contaminants of concern. However, the water industry lacks a comprehensive set of best practices for biofiltration use. To address this knowledge gap, the Water Research Foundation (WRF) launched Project 4459, Development of a Biofiltration Knowledge Base (http://bit.ly/OsQUdy), to catalog information from high‐rate biofiltration facilities across North America. [ABSTRACT FROM AUTHOR]

Biological filtration, an important process step for the production of microbially safe and aesthetically pleasing drinking water, has attracted increased attention within the water industry. In many cases,the most economical way to implement biological rapid filtration is to achieve biodegradable organic matter (BOM) removal and particle removal within the same filter unit, i.e., single-stage biological filtration. This requires optimization of the filtration process, keepingin mind both treatment goals: BOM and particle removal. This articlepresents a critical review of the key parameters and engineering variables influencing the biological performance, as well as the conventional performance, of biologically active filters. Several areas requiring further research have been identified. [ABSTRACT FROM AUTHOR]