Removal of E. coli and helminth eggs in UASB: Polishing pond systems in Brazil.

Ponds following anaerobic reactors, such as Upflow Anaerobic Sludge Blanket (UASB) reactors, have been termed polishing ponds in the literature. The present paper analyses the removal of E. coli and helminth eggs in five UASB-polishing pond systems in Brazil. Since there were ponds in series, the total number of ponds was 10. The ponds had average retention times varying from 2 to 21 days, and depths ranging from 0.40 to 2.00 m. The shallow ponds in series, even with low retention times, were able to produce effluents complying with the coliform WHO guidelines for unrestricted irrigation (< or = 1000 MPN/100 ml). An equation for the coliform decay coefficient was proposed: Kb (dispersed flow) = 0.710H(-0955) (20 degrees C). The equation highlights the inverse relationship between the pond depth and the decay coefficient. All polishing pond systems were able to produce effluents with helminth eggs concentrations predominantly equal to zero, and satisfying the WHO guidelines for unrestricted and restricted irrigation (< or = 1 egg/L, arithmetic mean). The approximate range of helminth eggs removal efficiency was predicted satisfactorily.     

Crafting Internal Hybrids: Complementarities,Common Change Initiatives,and the Team-Based Organization

Hybrid governance forms that seek to meld the virtues of both market control and traditional hierarchical control are alluring. Comparatively little research, outside of the M-form literature, has examined internal hybrids - hierarchical forms infused with elements of market control. This paper contends that common change initiatives, such as TQM, re-engineering, autonomous work teams, and group-based rewards, are appropriately viewed as attempts to craft internal hybrids by selectively infusing elements of market control within hierarchy. However, these change initiatives are often implemented in isolation and, as a consequence, violate patterns of complementarity that sustain traditional hierarchy or support the stable infusion of market control.The paper argues that these violations of complementarity often spiral hierarchies toward fundamental transformation. The clear trajectory of these transformations is to quite radically disaggregated organizations structured around teams. The paper presents both theory and evidence supporting the existence of complementarities among these common change initiatives.     

Detection of fatty acid beta-oxidizing syntrophic bacteria by fluorescence in situ hybridization.

A new 16S rRNA-targeted oligonucleotide probe, specific for the cluster of fatty acid beta-oxidizing syntrophic bacteria of the family Syntrophomonadaceae was designed for fluorescence in situ hybridization. This probe was evaluated with target as well as non-target cultures. Moreover this probe was assessed with butyrate and oleate degrading enrichment cultures and methanogenic sludges from full-scale plants. The results showed that the probe revealed the presence of fatty acid beta-oxidizing syntrophic bacteria in some of the samples analyzed. However, cell quantification was possible only in enrichment cultures and in a flocculent sludge from a reactor that treats lipid-rich wastewaters, but not in methanogenic granular sludges from upflow anaerobic sludge blanket reactors.     

Understanding community receptivity to water re-use: Ku-ring-gai Council case study.

This social research project investigated community receptivity to using rainwater and greywater as alternative domestic water sources. It was focused in the Ku-ring-gai local government area in northern Sydney, and involved a household questionnaire followed by community leader interviews and resident focus groups. Trends, such as a prolonged drought and increasing population, compound the current crisis and concern facing Sydney's available water supply. Substitution of domestic potable water has been promoted as part of the solution. The research results revealed that community receptivity was highest for external uses, such as watering gardens and flushing toilets, and progressively decreased with increasing personal contact. Receptivity to greywater reuse fell more rapidly with the community believing there was a higher health risk associated with its use. Gender and cultural background were revealed as significant variables and give insight into the design of strategies to target these demographic groups. This evidence provides a reliable stocktake of current receptivity revealing that the community has good awareness and positive association with water reuse for many household activities. This now needs to be harnessed through programs targeted at developing skills, resources and motivation for new water reuse practices and technologies across diverse social groupings.     

The effects of deep zones on wetland nitrogen processing.

Twelve research wetlands were operated under varying conditions at a site west of the city of Phoenix. These were constructed as a triplicated design, with zero, one, two and three internal deep zones, all containing an inlet distribution and an outlet collection deep zone, together comprising 12.5-35% of the wetland areas. The water supply was partially nitrified effluent from a city wastewater treatment plant. Total nitrogen was reduced by about 50%, from inflow concentrations between 6 and 8 mg/L. Speciation of the inflow was approximately 25% organic nitrogen, 25% ammonium nitrogen and 50% nitrate nitrogen. Typical outflow concentrations were about 1.2 mg/L organic, 0.5 mg/L ammonium and 0.0-2.5 mg/L nitrate. Rate constants for total nitrogen were 15-20 m/year at 20 degrees C, and 20-30 m/year for nitrate, which agree well with other project reports. Temperature factors averaged 1.100 for total nitrogen, and 1.184 for nitrate. There were no differences in the internal hydraulics with deep zone numbers. Deep zone numbers in the wetlands did not affect nitrogen treatment performance. No differences with deep zone numbers were found for temperature, dissolved oxygen, pH, or nitrogen removals or rate constants. In conjunction with other reported results, there appears to be no large treatment benefit or detriment of incorporating internal deep zones in free water surface wetlands.     

Diel Vertical Migration of Round Goby Larvae in the Great Lakes

One hypothesis for the transcontinental and intra-Great Lakes basin transfer of round gobies (Neogobius melanostomus) has been that round gobies were pumped into the ballast water of ships. During June 2005 in Lake Erie, we obtained evidence of a vertical migration of round goby larvae, when we collected 167 round goby larvae in surface ichthyoplankton net tows at night and zero during day. These results complemented similar findings from the Muskegon River estuary of Lake Michigan during 2003 and 2004, documenting diel vertical migration for the first time in larval round gobies. We suggest vertical migration behavior may have allowed larval round gobies to be transported to and within the Great Lakes via ballast water and dispersed in the Great Lakes via advection of 6.5–8.5-mm long larvae at the surface. Based on our results, if ballast water was only taken on near the surface during daylight hours from May through September when larval round gobies were present, it would have mitigated the spread of round gobies throughout the Great Lakes.     

Off flavours in large waterbodies: physics, chemistry and biology in synchrony.

The Laurentian Great Lakes of North America are a drinking water source for millions of Canadian and US consumers. These waterbodies have undergone extensive change over the past century as a result of widespread degradation and remediation. Many of the Lakes are prone to taste and odour (T&O), and although these outbreaks have been poorly monitored, evidence suggests that they are increasing in frequency. Tracing and controlling T&O in such large systems presents a challenging task, due to their physical size and complexity. This paper presents an overview of recent investigative and management approaches to T&O in Lake Ontario and its outflow, the St. Lawrence River. We have identified three distinct patterns of T&O in these source-waters, caused by geosmin and 2-methylisoborneol and differing in their planktonic and benthic sources, and temporal and spatial dynamics. Each pattern has required a different approach by scientists and management, in partnership with the water industry. We have shown these T&O outbreaks are caused and moderated by physical, chemical and biological mechanisms over a spectrum of spatial and temporal scales. Canadian municipalities affected by these outbreaks have been key to the investigation of the links between T&O and ecosystem processes with the aim to develop more proactive water treatment and long-term management.