Novel "Single-Pass" Wastewater Treatment Process Design
The system is designed with reduced process complexity, and to provide additional functionality, enabling a reduction in overall tankage. This was accomplished by re-evaluating each step and achieving more removal / treatment per tank. The result is a streamlined single-pass wastewater treatment design. Complexity, (i.e. moving parts) is removed where possible to keep operator maintenance and energy costs to a minimum.
As part of identifying enabling technologies we have analyzed all current solutions for wastewater treatment and have identified fixed film solutions as offering the best option for reducing the energetic input (kWh/m3) to the system. IWT carried out 2 years of R&D focused on identifying polymer materials that are best suited to biofilm formation. Our studies have shown an increase in treatment rates of up to 50% when compared to control samples, as shown in Figure 3. Improved polymer materials have been identified or developed that can allow for the enhanced removal of BOD, TSS and TKN. As shown in Figure 4, the fixed film was developed to have both a polished and treated side. The material alterations were tested by Carleton University. This unique setup allows for improved solids settling on the polished side, while providing additional surface area for bacteria growth on the treated side. When the media is used in the reactor, the fixed film is angled along the flow-path in the reactor. The fixed film serves a dual purpose of lamella plate type clarification at the same time as providing a surface area for biological growth. This structure essentially creates "tubes" which the wastewater is forced through. The tube "top" is treated specifically to provide additional surface area for biological growth. The tube "bottom" is smooth to allow solids the chance to accumulate and slide down the media and settle out of solution.
IWT has developed a biological filter for the REGEN product. This component provides the dual purpose of solids / COD filtration as well as a large surface area for bio-growth and some adsorption processes. Depending on the treatment requirements of the REGEN, this granular material has the option of being just a physical filter unit, or with the addition of aeration, it can provide additional bio-active filtration and Nitrogen removal. The large surface area provides an excellent medium for biological growth and for solids removal. GAC filtration allows the unit to meet treatment standards rapidly during start-up, and helps produce a higher quality effluent. The biomass is attached directly to the fixed film surface. This results in a lower concentration of suspended solids in the bulk liquid. As a consequence, the advanced fixed film system produces approximately 50% less sludge at the end of the treatment process when compared to conventional activated sludge processes.
The power skid, otherwise known as the backup power system, includes all the control and automation to ensure that the overall AC dependent system is powered correctly and on a consistent basis. This involves the control, monitoring and selection of the following sources:
Solar Photovoltaic (PV) Paneling;
Battery Based Energy Storage System;
13 kW 120/240VAC Auxiliary Generator; and
120/240VAC Grid power.
Source selection is carried out via the combined inverter battery charger major device and is set to consider a supply hierarchy which prioritizes solar power and energy storage over diesel generation and grid power. Bypass functionality is also built into the design with a safety interlock system. During the testing period the REGEN 20 was powered fully by solar energy and energy storage system.