Application of Freeze Concentration Technologies to Valorize Nutrient-Rich Effluents Generated from the Anaerobic Digestion of Agro-Industrial Wastes

The production of biogas through anaerobic digestion implies the generation of 90–95% of digested raw material, namely digestate. A nutrient-rich stream is generally applied to cropland to enhance yields, due to its high abundance of nutrients. Nevertheless, the intensive digestate farming brings about nutrient saturation and groundwater contamination. The application of downstream emerging technologies that focus on the recovery of nutrients from digestate have been studied, yet freeze concentration technology (FC) has never been considered for this purpose. This study evaluates the performance of FC technology applied to concentrate nitrogen (N), phosphorus (P) and potassium (K) from an effluent of a reverse osmosis unit that is treating the digestate of agro-industrial waste effluents. For this aim, two lab-scale methodological approaches were investigated, namely, progressive FC (PFC) and suspension FC (SFC), set through the utilization of different FC configurations. The concentrates obtained in both FC methods agreed with the regulations for fertilizers in terms of nutrients and metals content; meanwhile, the diluted fraction can be delivered as water for irrigation in high-density livestock areas. The application of FC solves the transportation cost side effect of livestock waste on the one hand, and soil contamination with nutrient on the other hand.

Protocol for local on-site dialysate production for continuous renal replacement therapy during the COVID-19 pandemic

Acute kidney injury frequently occurs in patients with COVID-19 and injury severe enough to require renal replacement therapy (RRT) is a common complication among critically-ill patients.[1-3] During the surge, there was a high demand for dialysate for continuous RRT, and this increase in demand coupled with vulnerabilities in the supply chain necessitated alternative approaches, including internal production of dialysate. Using a standard hemodialysis machine and off the shelf supplies as per Federal Drug Administration (FDA) guidelines, we developed a method for on-site dialysate production that is adaptable and can be used to fill multiple bags at once. The use of a central reverse osmosis unit, dedicated hemodialysis machine, sterile bags with separate ports for fill and use, and frequent testing will ensure stability, sterility and therefore safety of produced dialysate. Dialysate made in house was tested and showed both stability and sterility for at least 30 hours. This detailed description of our process for generating dialysate can serve as a guide for other programs experiencing similar vulnerabilities in the demand vs. supply of dialysate.

Improvement of quality of recirculated water supply of oil refineries

The relevance of this work is associated with the need to reduce the volume of water used by returning it to the start of the technological process. Thus, the work aims to improve the quality of the recycled water supply to petrochemical and oil refineries, in particular Atyrau Refinery LLP. This article provides data on purification of blowdown water by reverse osmosis method. A pilot reverse osmosis unit with a capacity of 600 l / h has been manufactured and a technological scheme for purification to standards that meet the requirements of make-up water has been developed, as well as a technical task for the design of industrial recycling water supply systems and appropriate recommendations have been provided.

RESEARCH OF THE EFFICIENCY OF REAGENT-FREE ELECTROMAGNETIC TREATMENT OF SOURCE WATER AT PETROCHEMICAL ENTERPRISES

A technological scheme and technical documentation for the manufacture of a test bench with a purified water capacity of 300 l/h have been developed. Long-term tests were carried out on a test bench, as well as analysis of the quality of the sampled water before purification, with the use of an electromagnetic treatment device and without it. As a result of the tests carried out, it was found that the total salt content after the reverse osmosis unit decreased from 535.5 to 30.0 mg / l, and in water with the use of magnetic water treat- ment – from 535.5 to 12.7. Moreover, the pH in the first case varied from 8.3 to 6.2, in the second – from 8.3 to 6.44. It has been established that the use of magnetic water treatment in desalination before the reverse osmosis unit has a positive result, namely, calcium and magnesium salts do not settle on the reverse osmosis membranes, thereby prolonging the service life of the reverse osmosis membranes.

Design a Portable Photovoltaic - Reverse Osmosis Unit for Brackish water as Pathway to Develop Remote Communities

In this paper, the operation design of a portable unit for PV RO system for small communities was studied with direct conducting with solar panel and without batters storage system. In this paper the system configurations will be without batteries. In all conditions assessed, the unit showed good performance. The test rig, indicated that the unit comfortably produced at 8.5 l/h with 500 ppm feed salinity, 7.73 l/h with 1000 ppm feed salinity, 5.99 l/h with 1500 ppm feed salinity, 4.69 l/h with 2000 ppm feed salinity, 4.45 l/h with 2500 ppm feed salinity, 4.25 l/h with 3000 ppm feed salinity Sequentially with little work input from an operator. The energy consumed at varies salinity input test as 1.12 Kw.h/m3 with 500 ppm feed salinity, 1.34 Kw.h/m3 with 1000 ppm feed salinity, 1.71 Kw.h/m3 with 1500 ppm feed salinity, 2.20 Kw.h/m3 with 2000 ppm feed salinity, 2.33 Kw.h/m3 with 2500 ppm feed salinity and 2.49 Kw.h/m3 with 3000 ppm feed salinity Sequentially. The unit is easy and efficient to operate without batteries storage and with little regular maintenance. It is not practical to conduct a continuous monitoring of the system. So it needs to operate using automatic control system. In all the conditions assessed, the unit showed good performance. It is clear that the dissemination of this technique is made easier and improves efficiency to be more common.

Hard water syndrome: a case series of 30 patients from a London haemodialysis unit

Severe and life-threatening hypercalcaemia can develop in haemodialysis patients dialysed against a dialysate with a high calcium concentration, the so-called hard water syndrome. Here we describe the development of hard water syndrome in 30 patients following sequential failure of the reverse osmosis unit and water softeners. Serum calcium levels rose from 2.43 ± 0.19 to 3.92 ± 0.51 mmol/L after exposure. All patients required emergency haemodialysis and four acutely deteriorated, one of whom was 24 weeks pregnant. This is the largest reported series of patients affected by this rare and severe condition. This event led to the introduction of processes to minimize future risks.