Water Quality Management
Evesham Municipal Utilities Authority (EMUA)
Omni has provided NPDES permitting assistance for all of EMUA's several treatment plants, including review of draft permit terms and conditions, preparation of comments on draft permits, preparation of final permit appeals, negotiations with NJDEP regarding permit terms and particularly effluent limitations, water quality studies including phosphorus studies and ammonia toxicity studies, and calculation of effluent limitations for various parameters. Omni's work has led to the deletion of unnecessarily stringent effluent limitations for phosphorus and ammonia.
Ewing Lawrence Sewerage Authority (ELSA)
Omni has provided various forms of NPDES permit assistance for nearly 20 years to the ELSA wastewater treatment facility, which has a permitted capacity of 16 mgd and discharges to the Assunpink Creek, a tributary to the Delaware River. Services have included review of draft permit terms and conditions, preparation of comments on draft permits, and preparation of final permit appeals; negotiations with NJDEP regarding permit terms and conditions, particularly effluent limitations; water quality studies including phosphorus studies and metals translator studies; calculation of effluent limitations for conventional pollutants as well as metals and toxic organic pollutants; and NPDES permit compliance assistance and representation. Omni's work has resulted in the deletion of unnecessary effluent limitations for cadmium, lead, nickel, silver, zinc and chloroform.
Southwest Delaware County Municipal Authority (SWDCMA)
Omni performed the recalculation procedure to determine site-specific acute and chronic criteria in Chester Creek, to which the SWDCMA wastewater treatment plant discharges. Chester Creek is protected under the classification of warm water fishery, and the Pennsylvania Department of Environmental Protection proposed an effluent limit that was assumed to be necessary to protect the Creek's indigenous biota. Omni used national laboratory data on species representative of Chester Creek to determine the criteria needed to protect the Creek's biota, allowing for relaxation of the permit limit.
DuPont Chambers Works Wastewater Treatment Plant
Omni completed an effluent dilution study for a proposed outfall diffuser at the DuPont Chambers Works wastewater treatment plant in Deepwater, New Jersey. The study involved application of the computer simulation model CORMIX to calculate the amount of mixing that would be achieved by a new outfall diffuser. The results of the model output were used to calculate the size of the mixing zone to be allocated to the discharge. Effluent and receiving water data analysis along with water quality modeling calculations were performed to determine the required effluent dilution factor such that there would be no reasonable potential for water quality criteria exceedances outside of a specified mixing zone. The mixing zone corresponding to the required effluent dilution factor was then determined and formed the basis for a request for an alternative mixing zone under applicable regulations promulgated by the Delaware River Basin Commission (DRBC). This project required close interaction with DRBC and a thorough understanding of DRBC's regulations and USEPA's and NJDEP's methods for calculating NPDES effluent limitations.
Montgomery Township Wastewater and NPDES Support
Over the last 20 years, Omni has assisted the Township in addressing a wide range of wastewater and other environmental issues including: alternatives evaluation, facility planning, and design for an $11.2 million upgrade of the Skillman Village Wastewater Treatment Plant using state-of-the-art membrane bioreactor (MBR) technology; design management for the $14 million upgrade and expansion of the Pike Brook Wastewater Treatment Plant using MBR technology; extensive regulatory support for all seven of the Township's treatment plants; evaluation of cost effectiveness of eliminating one of those plants and consolidating treatment at another; current design of two replacement pumping stations; monitoring in and modeling of each of the Township's streams, including extensive water quality and hydrologic data collection; stormwater engineering services utilizing green technologies; and serving as the Township's Wastewater Engineer to provide technical, regulatory, and permitting support on an as-needed basis.
Saylor Grove Treatment Wetland
Omni designed and oversaw construction of a stormwater treatment wetland to help protect the water supply of the City of Philadelphia. The wetland system was incorporated in Fairmount Park, and was designed to capture and treat the first flush runoff volume of larger storms and the entire runoff volume for smaller storms. Features include a series of falls and pools to dissipate energy, easy-to-clean sediment traps, and a four-foot-deep permanent pool to promote a diverse ecosystem. Volunteers were trained and supervised to assist with the wetland planting, reducing costs and promoting wetland stewardship.
Frenchtown Borough Wastewater Support
Omni completed an expansion and upgrade facility plan and recently finalized design of the recommended alternative for a new advanced wastewater treatment plant to replace an existing trickling filter plant constructed in the 1960s. The new plant will have an expanded capacity of 0.4 mgd to meet future development and redevelopment needs and will provide an advanced level of treatment to comply with the Delaware River Basin Commission's Special Protection Waters requirements. Challenges include a very tight site in the 100-year flood plain that is surrounded by threatened and endangered species habitat, and exceptional resource value wetlands within 150 feet.
Kline's Island Wastewater Treatment Plant
Omni has served the City of Allentown, PA since 2007 by addressing various issues related to the 40-mgd treatment plant and its tributary collection system. Projects have included preparing a progress report to the USEPA on complying with an Administrative Order to reduce infiltration and inflow and reduce sanitary sewer overflows, developing and presenting a wet-weather flow management plan, developing and presenting seven feasible alternatives to reduce the use of the plant's emergency bypass outfall, and preparing a Conceptual Expansion Plan to take the plant to 44 mgd under two different scenarios.
Long Hill Township Wastewater Support
Omni completed a study of alternatives to provide sufficient capacity for the current and future development and redevelopment needs of the Township, which has been under a sewer ban for several years due to insufficient treatment plant capacity, as well as alternatives to achieve compliance with a future Total Phosphorus effluent limitation of 0.76 mg/L. The capacity alternatives included various combinations of sewer system rehabilitation to reduce infiltration and inflow and plant improvements to increase treatment capacity.
Parsippany-Troy Hills Treatment Plant Redesign Study
Omni conducted a study to determine the cost effectiveness of reconfiguring the Township of Parsippany-Troy Hills' existing 16-mgd treatment plant to a more efficient and compact process while also achieving anticipated future effluent limitations for phosphorus and nitrogen. Key tasks included data collection and wastewater characterization, screening and ranking of 23 possible reconfiguration alternatives, process modeling of the highest ranked alternatives, and a detailed cost evaluation of the two most viable options.
Stony Brook Regional Sewerage Authority
For over 25 years, Omni has served the Authority in a variety of capacities. Recent projects have included design and construction phase services for an ARRA-funded project to install new and more efficient mechanical aerators and to replace existing chemical storage and feed systems at the 13.2 mgd River Road Plant; evaluation of alternatives to construct new influent screening, grit removal and odor control facilities at the River Road Plant; the current design of the recommended screening, grit removal and odor control facilities; preparation of a Wastewater Management Plan for the 0.3-mgd Pennington Plant; assistance with various regulatory and permitting matters; and general technical support on an on-call basis.
Madison-Chatham Joint Meeting (MCJM) Wastewater and NPDES Support
Omni has assisted MCJM on a number of issues related to its anticipated future Total Phosphorus limit of 0.76 mg/L, including evaluating removal alternatives (chemical precipitation was recommended), developing a detailed work plan for full-scale demonstration testing based on the selected coagulant following jar testing, coordinating with MCJM to set up temporary facilities for coagulant feeding, monitoring and evaluating laboratory data as collected by MCJM as well as assistance with troubleshooting, interpreting data results to estimate the required average and maximum dose, and providing advice and consultation during MCJM's participation in litigation between the Passaic River Basin Alliance and NJDEP. Omni has also provided a variety of NJPDES-related support services to MCJM over the past several years, including a local limits evaluation and the recent preparation of a detailed capacity assurance program report.
Pennington Borough Wastewater Management Planning
Omni performed a comprehensive Wastewater Management Plan Update to accommodate an expansion of the service area and treatment capacity of the Pennington Wastewater Treatment Plant. An Environmental Constraints Analysis was completed to assess the plan's potential impacts on natural resources, and an anti-degradation study was performed to determine if the expansion could be permitted. Services also included development of a complete GIS, preparation of sewer service area maps, identification and mapping of environmentally constrained areas, and mapping and compilation of data and information for multiple treatment plants within the Township.
Non-Tidal Passaic River Nutrient TMDL Study
Omni completed a nutrient TMDL study of the Passaic River Basin. Extensive monitoring was conducted throughout the Passaic River Basin. A total of 70 locations were sampled, including streams, stormwater drainageways, sewage treatment plant effluents, and baseflow locations. Water quality targets (e.g. dissolved oxygen criteria) were defined to solve or prevent nutrient impairments at critical locations in the streams. Omni developed a state-of-the-art interface between a flow model developed by USGS and the water quality model developed by Omni, incorporating a nonpoint source loading model into a GIS. Wasteload allocations for point sources and load allocations for nonpoint sources were calculated to satisfy water quality targets at all critical locations. This study provided a scientifically defensible approach for watershed-specific criteria and a TMDL for the non-tidal Passaic River Basin that was adopted by NJDEP and approved by USEPA. Omni also worked with Rutgers University to develop a point source trading system to optimize the TMDL implementation. Our work on this project was adopted as an amendment to the Northeast Water Quality Management Plan.
Watershed Management Planning for Rancocas Creek
Omni prepared an interactive and educational watershed characterization report for the Rancocas Creek Watershed to allow stakeholders to understand the watershed's baseline conditions through exploring and experiencing rather than simply reading. This included collecting all data from various agencies, municipalities, and counties, along with in-house data, into a database and GIS; presenting and summarizing the information, as well as providing analysis of that information aimed at identifying watershed management issues; and providing recommendations for watershed management initiatives to correct real or perceived problems.
Wetland Restoration in County of Union, NJ
Omni completed a wetlands restoration project in Rahway, NJ that relocated residents from a flood-prone area and restored the filled riparian area to its former wetland state, providing wildlife habitat, managing stormwater runoff quality and quantity, and providing passive recreation. Omni prepared design plans and applied for the necessary permits.
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