J. C. van Dijk

In the context of the present work it is hypothesized that the condition of a PVC push-fit joint can be obtained from the analysis of the joint's gap width. A perfectly jointed and aligned pipe, for example, should have a constant gap for the complete pipe diameter while a bent joint should show variations of the gap width with the diameter. Therefore, laboratory tests were performed to test the applicability of ultrasound in the assessment of PVC push-fit joints which are ubiquitously used in the Netherlands. In those tests the potential of ultrasound to detect changes in geometrical alignment of PVC pipes was evaluated using a specially built metallic loading frame. This frame supported two 2-meters O/315 mm PVC pipes connected with a push-fit joint. This pipe could be kept in horizontal position or be bent up to an angle ofca. 5 degrees in 11 uniform steps. Results show that when two pipes have a perfect alignment (zero degrees angle between the pipes) the tested ultrasound tool describes quite adequately the real situation and gives good information about the joint's real condition. However, when an angle is imposed on a PVC joint the ultrasound results are not consistent with reality. This discrepancy is probably due to both longitudinal and shear ultrasound waves echoing back to the transducer from the PVC wall. The creation of both longitudinal and shear waves occurs when an angle between the ultrasound transducer and the object being studied exists. This factor is known to complicate the resulting ultrasound scans and the interpretation of the results. In conclusion, for this application ultrasound inspection is vulnerable to changes in geometrical alignment of assessed pipes. Even being unanimously considered as a potential technique for the inspection of polymeric pipes, ultrasound tool is not capable of giving results that permit accurate detection of all known failure mechanism of joints.

Advanced Oxidation Processes (AOP) are known as an effective treatment barrier for micropollutants. Well known AOP combinations are UV/H2O2 and O3/H2O2. This paper will present a more detailed view on how to use the different options combining UV; ozone and H2O2. The focus of this investigation is on treatment effects (reduction of specific contaminats), water matrix, energy consumption and cost calculation (CAPEX, OPEX). The presented data are extracted from extended pilot trials carried out at DUNEA in 2009 and 2010. Dunea (The Netherlands,The Hague) produces drinking water from the Meuse River, which contains a variety of organic micropollutants as a result from upstream activity. Dunea is performing research to extend the current multiple barrier treatment (e.g. pre-treatment, artificial recharge and recovery (ARR), post-treatment) with an advanced oxidation processes (AOP), situated at the pre-treatment location in Bergambacht, before ARR. The degradation of organic micropollutants as a result of advanced oxidation using different combinations of hydrogen peroxide, ozone, low pressure (LP) UV lamps has been assessed by means of pilot-scale (5 m3/h) experiments. The influent was pre-treated river water, with an yearly average UV-transmission of 80% and a DOC concentration of 4 mg/L.The peroxide doses were varied as 0, 5 and 10 ppm, the ozone doses were varied as 1, 2 and 3 g ozone/m3. The UV doses were varied between 300 and 650 mJ/cm2. The installed power for the LP reactor was 0.26 kWh/m3. Atrazine, bromacil, ibuprofen and NDMA were spiked (10-20 µg/L) and used as model compounds. Bromacil was completely (>99%) removed by ozone/peroxide. Atrazine and ibuprofen were good (58% and 85% respectively) removed by O3/H2O2 and NDMA was not (9%) removed by this technique, whereas NDMA showed good (82%) removal by UV/H2O2. Atrazine, bromacil and ibuprofen were degraded by UV/H2O2 at 53, 46 and 59 %, respectively. In addition also combined AOP was tested; spiked water was treated by O3/H2O2 first and let over the LP-UV reactor directly afterwards. All four compounds showed highest degradation during combined AOP treatment. With this combined AOP, lower ozone dose and lower UV dose result in comparable degradation compared to single AOP treatment. For all these techniques a detailed capital expenditure operational expenditure (CAPEX / OPEX) evaluation was carried out based on a daily water flow of 240,000 m3/d. This evaluation resulted in the finding, that the combined AOP is the most economical solution with the best treatment result. Other advantages of the combined AOP are limited by-product formation, especially bromate, and a future barrier against OMPs encompassing a broad spectrum of properties.

The end-use model SIMDEUM for residential water demand has been extended to incorporate nonresidential water demand. The model was developed to predict water-demand patterns with a small timescale (1 s) and small spatial scale (at the water meter connection). The end-use model is based on statistical information about users and end uses: data on occupancy; the frequency of use; duration and flow per water-use event; and the occurrence over the day of different end uses, such as flushing the toilet, doing the laundry, and washing hands. The model follows a modular approach, in that each type of building is composed of functional rooms, such as lodgings, restaurants, and conference rooms. A functional room is characterized by its typical users and water-using appliances. With this approach, nonresidential buildings’ water-demand patterns over the day can be simulated. The simulation results for an office building, a hotel, and a nursing home were compared to measured water-demand patterns with regard to att...

The effectiveness of demineralized water backwash on ultrafiltration (UF) fouling control of seawater is investigated in this study. Fouling experiments for two different backwashes (UF permeate and demineralized water) were conducted at three fluxes: 120, 180 and 240 L/(h m2) to compare their fouling control efficiency on UF membranes. Results show that backwashing with demineralized water improved the fouling control of UF membranes. When the UF membranes were backwashed with demineralized water, probably because more foulants were flushed away from the UF membrane than UF permeate backwashes, the increase in trans membrane pressure (TMP) for backwashing with demineralized water was less than that with UF permeate. Furthermore, the fluxes of experiments also played a role on the fouling control. When the flux was 120 L/(h m2), the difference between two different backwashes was small. However, at the flux of 240 L/(h m2), the TMP for backwashing with UF permeate increased faster than that with demineralized water, although the TMP for backwashing with demineralized water increased as well.

A water demand end-use model was developed to predict water demand patterns with a small time scale (1 s) and small spatial scale (residence level). The end-use model is based on statistical information of users and end-uses: census data such as the number of people per household and their ages; the frequency of use; duration and flow per water-use event; occurrence over the day for different end-uses such as flushing the toilet, doing the laundry, washing hands, etc. With this approach, water demand patterns can be simulated. The simulation results were compared to measured water demand patterns on attributes such as peak flow and daily total water use, as well as on the shape of the pattern and the frequency distribution of flows and accelerations in flow. The simulation results show a good correspondence to measured water demands. Because the end-use model is based on statistical information rather than flow measurements, the model is transferable to diverse residential areas in different countries. Th...

There is growing interest in modeling water demands on short time scales (as brief as one second) and small spatial scales (typically single homes). Buchberger et al. (1996, 2003) have developed the Poisson Rectangular Pulse (PRP) model for this purpose. Blokker et al. (in prep.) have developed an end-use model SIMDEUM (which stands for SIMulation of Demand, and End-Use Model) which is based on statistical information from end-uses and does not require any flow measurements. SIMDEUM was developed and validated for Dutch water use. In this paper the PRP model and SIMDEUM are compared with each other and with measured indoor water demands from 21 homes in Milford, Ohio. Both models compare well to the measurements; the PRP model works better in simulating the cumulative flows of a sum of 20, SIMDEUM works better in simulating the flows of a single home.