This pilot study was conducted to assess the utility of using a health insurance database for the automated detection of waterborne outbreaks of acute gastroenteritis (AGE). The weekly number of AGE cases for which the patient consulted a doctor (cAGE) was derived from this database for 1,543 towns in three French districts during the 2009–2012 period. The method we used is based on a spatial comparison of incidence rates and of their time trends between the target town and the district. Each municipality was tested, week by week, for the entire study period. Overall, 193 clusters were identified, 10% of the municipalities were involved in at least one cluster and less than 2% in several. We can infer that nationwide more than 1,000 clusters involving 30,000 cases of cAGE each year may be linked to tap water. The clusters discovered with this automated detection system will be reported to local operators for investigation of the situations at highest risk. This method will be compared with others before automated detection is implemented on a national level.
Case study - An air/ozone Sparge curtain to protect a municipal supply well
DescriptionReleases of petroleum contaminants from a retail gasoline station in a medium-sized California Central Valley town threatened a municipal supply well immediately adjacent and approximately 200 ft downgradient to the station. Methyl tert-butyl ether (MTBE) was present in groundwater concentrations up to 30,000 micrograms per liter (µg/L) and GRO up to 33,000 µg/L in the first-encountered groundwater aquifer, between 30 to 45 feet below ground surface (BGS). The concern was that the MTBE...
Case study - Hong Kong
To meet the forecasted increases in demand for potable water, the new Tai Po Water Treatment Works has been built in Hong Kong. The plant has a production capacity of 1200 Ml/dayThis solution strongly reduced the chlorine demand for the plant compared to the alternative execution with break point chlorinaThe water treatment works takes water from the river Dongjiang in the Guangdong Province north of Hong Kong. The raw water has an average turbidity level of around 11 NTU and contents, among other things, ammonia...
Ballast water treatment on Alaskan coastline - Case Study
An Alaskan oil terminal had to deal with contaminated ballast water that needed to be collected and treated before discharge. They had a biological treatment process on site, but it was difficult to operate in the temperature and contaminant loading extremes the site experiences and they struggled to get it to work consistently. The plant is also required to treat spring snowmelt and rain that falls within the site boundaries, creating extremes of liquid temperatures and contaminant concentrations. QED ran...
PRB Installation at Superfund Site Using Angled Drilling - Case Study
ABSTRACT BOS 100® was injected adjacent to and beneath a stream using a direct push angle drilling technique to successfully create a PRB and limit PCE flux from the upgradient source area into the stream. CHALLENGES The Superfund site is a former textiles facility where tetrachloroethylene (PCE) was used in dry-cleaning operations. Approximately one-half mile downgradient of the source PCE (100-300 μg/L PCE) was discharging into a stream through the saprolitic formation (weathered gneiss and schist)....
Ceramic Membranes in Sludge Thickening Applications
The Aerobic Digestion group has recently been conducting pilot testing of silicon carbide ceramic membranes manufactured by the Danish company Cembrane A/S. This promising technology shows a great ability to filter water even in the challenging high solids environment of sludge thickening. The results of the pilot testing have led the aerobic digestion group to utilize Cembrane’s membranes as the basis of design for sludge thickening projects moving forward and have signed an exclusive distribution license...