The precipitation of struvite (MgNH₄PO₄.6H₂O) from wastewater streams simultaneosuly recovers nitrogen (N) and phosphorus (P) for reuse as fertilisers. Struvite crystallisation is controlled by pH, saturation index, temperature and other ions in the solution (e.g., Ca²⁺, Mg²⁺ and CO₃²⁻). This work studies the effect of pH and temperature on phosphorus and nitrogen removal via struvite precipitation and the quality of the resulting precipitate product (i.e., crystal size, morphology and purity). Struvite was precipitated in batch reactors from the supernatant produced during anaerobic sludge dewatering at a wastewater treatment works, under controlled pH (8, 9 and 10) and temperature (25, 33 and 40 °C) conditions. The optimal P removal as struvite, reduction of the co-precipitation with Ca and the increase in particle size of the struvite precipitates were determined. The results showed that temperatures of 33 °C and 40 °C are not recommended for struvite precipitation—i.e., at 33 °C the purity is lower, and at 40 °C the ammonia losses are induced by volatilisation. At all pH-tests, the P removal efficiency was >93%, but the highest phosphate content and purity as struvite were obtained at a pH of 9.0. The optimum pH and temperature for the formation of large crystals (84 µm) and a high purity (>70%) of the struvite precipitates were 9 and 25 °C, respectively.

Significance of PBDE diffusivities in polymers for passive sampling and for the risk to biota when associated with microplastics.

Hepatitis E virus (HEV) is one of the main causes of acute viral hepatitis of enteric transmission. HEV has been detected in environmental samples in several countries from Europe and Asia, constituting a risk factor for waterborne infection. In Colombia, HEV has been identified in samples obtained from patients as well as from swine, but no environmental studies have been carried out. To determine if HEV is present in environmental waters, samples from the main source of drinking water plant and of wastewater system of eight municipalities and two villages of Antioquia state (North West Colombia), were collected between December 2012 and April 2014. The HEV genome was detected by RT-PCR in 23.3% (7/30) of the samples from the main source of drinking water plants and in 16.7% (5/30) from sewage. Viral concentrates obtained from three positive sewage samples were used to inoculate HepG2 cell cultures that were followed for one month; however, the viral genome was not detected in any cell culture. This study demonstrates the circulation of HEV in both source of drinking water plants and wastewater in Antioquia state, Colombia. The presence of HEV in environmental waters could be a risk for waterborne transmission in this population. The findings of the present study, together with the evidence of HEV circulation in human and swine in Colombia, should be consider by public health authorities for the development of surveillance programs and the inclusion of HEV infection diagnosis in the guidelines of viral hepatitis in the country. This is the first report of HEV in environmental samples in Colombia and the second one in Latin America.

This work aims to systematize the study of indicators for two types of wastewaters: carbohydrate-based and protein-based synthetic wastewaters. Characterization of steady states and dynamic response analysis against disturbances were carried out using both a factorial discriminant analysis (FDA) and a phenomenological analysis, respectively. This research seeks reconciling both sets of indicators in order to optimize resources and provide a minimal cost in instrumentation for its implementation at industrial scale. According to the results of this research, the best indicators for the two types of wastewaters, considering both process steady states and organic load perturbations are: Biogas flow rate or Methane flow rate, and Hydrogen concentration in the biogas; Volatile fatty acids and Partial alkalinity in the liquid phase.

This paper describes a validation procedure applied for an on-line titrimetric analyzer (AnaSense^®-Anaerobic Control Analyzer) prototype designed to detect of volatile fatty acids (VFA) and alkalinity (bicarbonate). The AnaSense^® analyzer was recently developed under the framework of the TELEMAC European Project. A pilot-scale evaluation of the analyzer was carried out in an anaerobic wastewater treatment plant, in a hybrid Upflow Sludge Bed Filter (USBF) reactor with an overall volume of 1.15 m³. The sensor uses two methods, both based on two-point titrimetric analyses, for determining VFA and alkalinity concentration. AnaSense^® performed on-line monitoring of VFA (13–4,900 mg · L⁻¹) and bicarbonate (2.5–49.5 mEq · L⁻¹), and demonstrated sufficient accuracy for both VFA and bicarbonate detection. Intermediate Alkalinity/Total Alkalinity (IA/TA) and Intermediate Alkalinity/Partial Alkalinity (IA/PA) ratios were also evaluated to test the suitability of the sensor for anaerobic digestion process control.