David H. Paul Inc.

Farmington, NM, United States

David H. Paul Inc.

Farmington, NM, United States
SEARCH FILTERS
Time filter
Source Type

Paul D.H.,David H. Paul Inc.
AWWA/AMTA Membrane Technology Conference and Exposition 2012 | Year: 2012

This paper documents the results of a 2,000 hour nanofiltration (NF) pilot study on very challenging North Carolina well water. The challenges were: • Very high iron, up to over 8 mg/L in some wells • Very high silica, up to over 70 mg/L in some wells • A combination of at least two wells is always required to be in operation at all times resulting in both very high iron and very high silica feed water • Silica and iron precipitation in the last elements occurred even at silica concentrations below the published maximum limit for the scale inhibitor used • Experimentation was required using different recovery rates and different scale inhibitors to control silica scaling. © 2012 American Water Works Association.


Dees W.E.,David H. Paul Inc. | Paul D.H.,David H. Paul Inc.
AWWA/AMTA Membrane Technology Conference and Exposition 2012 | Year: 2012

This paper documents the results of some of the first applications of the Direct Osmosis-High Salinity (DO-HS) technology used in the United States. The paper consists of: • A description of the mechanisms of fouling and how fouling is greatest in the first element of the first stage due to the high water flux rate at this location due to reverse osmosis (water flux from the feed side to the permeate side). • The reasons why chemical cleanings typically become ineffective over time. Illustrations and pictures of fouling on the surface of the membrane and on the downstream side of feed spacer fibers will be shown as well as video showing the flow path through new and fouled feed channels. It is then clear why chemical cleaning can be ineffective. • The process of direct osmosis as compared to reverse osmosis. Depending upon the feed water, a short-term pulse of typically 6-7% sodium chloride is injected into the RO or NF unit's feed stream just ahead of the high pressure pump for 10-15 seconds. Where the high salinity short-term pulse is present, there is a net movement of water molecules from the permeate side of the membrane to the feed side of the membrane. This lifts the fouling material off the surface of the membrane without causing any damage to the membrane. The fouling material then goes to drain. • Details of the equipment, process and results of one of the first applications of the DO-HS technology in the United States and why the facility choose to implement it. © 2012 American Water Works Association.


Decker R.,David H. Paul Inc.
Ultrapure Water | Year: 2010

DI is the removal of ions from a water stream. In high-purity water applications, the IX technology exchanges undesirable feedwater ions for hydrogen ions, and hydroxide ions to create ptue water. The EDR technology uses an applied electrical potential to "pull" ions out of a feedwater stream. The electrodeionization technology combines the ion exchange and electrodialysis technologies.


Siandfield H.,Newton Energy Center | Dees B.,David H. Paul Inc. | Paul D.,David H. Paul Inc. | Wilf M.,ROletlmulugy
Ultrapure Water | Year: 2012

The water treatment plant at Ameren Energy Resources' Newton Energy Center was constructed and commissioned in 1997. The plant consists of membrane filtration followed by reverse osmosis treatment. From the time of initial startup of the RO system, fouling of the membranes has been a continuous problem. The Direct Osmosis-High Salinity process has been implemented to control biofouling and reduce the frequency of membrane cleaning. The effectiveness of DO-HS process was initially tested on one RO train for a period of six months. Prior to membrane filtration, sodium hypochlorite, an aluminum-based coagulant, and a cationic polymer are injected into the influent. The presence of a coagulation in the feedwater prior to membrane filtration increase the operational time between backwash steps. A scale inhibitor, isothiazolin disinfectant, and sodium hydroxide are added to the RO feedwater before the cartridge filtration unit.


Decker R.,David H. Paul Inc.
Ultrapure Water | Year: 2010

A plate-and-frame EDI module comprises cell pairs stacked with an anode and cathode at opposite ends. ADC electrical potential applied across the stack causes cations and anions to migrate towards their respective electrodes. The membrane sheets are made of the same materials as conventional ion-exchange resin beads, and are mixed with a binder to hold them in sheet form. Feedwater anions are attracted to the anode and pass through the anion-exchange resin sheets. A unique phenomenon that occurs during EDI is water splitting. The more conductive the materials in the stack are the easier it is to pass the required current with the voltage available. The ion-exchange materials are many times more conductive than the water to be treated. The biggest source of resistance in a stack is typically the C-compartment because or due to the lack of resin beads.


Paul D.,David H. Paul Inc.
Ultrapure Water | Year: 2010

Compendial waters are made from PW or WFI. There are conductivity, TOC, and bacterial count limits for PW and WFI. There is also an endotoxin limit for WFI. There are generally several treatment steps using different water treatment technologies required to process a drinking-water-quality feedwater to PW and WFI. Each plant will have a unique process.


Turner E.,David H. Paul Inc.
Ultrapure Water | Year: 2010

An RO unit's operational data that is already being taken should be inputted into a trending program on a daily basis, and the trends analyzed on a weekly basis to catch problems at an early stage as possible before irreversible fouling/scaling can occur. The three trends to be graphed are NPF, DP, and % SR, or % SP. IfNPF decreases by 10% to 15%, or if DP increases by 15% to 25%, whichever comes first, the RO unit must be chemically cleaned. When trending is implemented at a plant, it generally results in smoother operation, less down time, and cost reduction of the overall operation of the water plant, which can save the company money.

Loading David H. Paul Inc. collaborators
Loading David H. Paul Inc. collaborators