Phosphorous Loadings to Streams in Residential Watersheds Using On-site Wastewater Systems in Comparison to Centralized Sewer

It is well documented that excessive nutrients can degrade ground and surface water quality. Phosphorus is a limiting nutrient in algae growth under certain circumstances, which can lead to fish kills and environmental problems (Fear et al. 2004). Waste water is a major source of nutrients in residential ground and surface waters. This study attempts to compare the nutrient loads to groundwater from two similar watersheds, one which uses on-site waste water treatment systems (OWTS), or septic systems, and another which uses a municipal sewer system. Physical characteristics such as rainfall, flow volume, soil types; and chemical parameters such as pH and nutrient and ion concentrations will be monitored strategically to gain understanding of what effects each system has on the local water quality. Surface water will be compared among the different watersheds to distinguish what differences can be expected among two different land uses, and compared to the effluent of municipal wastewater treatment plant.  Soil borings will capture characteristics of soils such as phosphorus and mineral content at each site. The overall goal is to better understand mechanisms and variances in nutrient loads to surface waters among sites using OWTS and municipal sewer in the context of Pitt County, NC, with a focus on phosphorus. As bulk this paper should add to the aggregate of evidence showing human interaction with the natural environment can have discreet measurable and sometimes acutely negative effects.

ECOLOGICAL WASTEWATER TREATMENT AND REUSE: THE DECENTRALIZED MODEL

Today's centralized model of wastewater treatment is expensive, energy intensive, complex, wasteful, and damaging to the nation’s freshwater, estuarine and marine ecosystems. Conversely, there are new innovative decentralized approaches to wastewater management that are energy efficient, cost effective and protective of the environment. The decentralized model also provides greater opportunities for water conservation and water reuse, thereby providing viable solutions to increasing water shortages. Critics of decentralized treatment and reuse argue that public health may not be adequately protected with distributed systems. Many decentralized treatment and reuse projects have relied on membrane bioreactors (MBRs), advanced treatment systems that provide excellent treatment performance but at very high energy and operations costs. Recently advanced wetland treatment systems have been used as energy efficient and cost effective treatment technology for water reuse in urban and rural locations. These systems provide performance equivalent to MBRs, with much lower capital and operating costs. Tidal-flow wetlands are modular energy-efficient advanced wetland treatment systems that utilize plants, microbial fixed-film ecosystems and innovative fill-and-drain "tidal cycling" to enhance aerobic and anoxic treatment processes. The ill-and-drain process allows the wetland footprint to be radically reduced, making these systems suitable for urban locations and larger flow rates. This presentation will provide in-depth information on the design, operation, and performance of recent advanced wetland treatment systems for reuse. Case studies will be presented from a Marine Corps base in San Diego, a school system in North Carolina, the headquarters facility of the Port of Portland at PDX, a pineapple plantation for Dole Foods in Hawaii, a CAFO pilot study in California, and the new headquarters for the San Francisco Public Utilities Commission in downtown San Francisco. Case studies cover a spectrum of wastewater concentrations and a number of water reuse applications, including irrigation, toilet flushing, and cooling tower make-up. Third-party performance data, including a recent CDC analysis of one of the case study sites, is used to address questions regarding public health of decentralized treatment and reuse. Regulatory challenges and solutions to achieving safe and cost effective reuse will be discussed.

Assessing Wastewater Infrastructure Needs – Using Trends to Establish Priorities in Environmental Programs

The most common approach in the United States for dealing with wastewater is the centralized sewer. Environmental laws and public funding largely promote and support the construction, operation and maintenance of large wastewater treatment facilities. Contrast that with historic population declines in many small communities in rural areas of the Upper Midwest and other rural areas of the United States of America, a trend that continues. For example, according to figures provided by the U.S. Census Bureau the median population of communities in Nebraska was 342 in 2000 which declined to 318 by 2010.

Regulatory requirements and demands on wastewater treatment systems continue to increase. The blanket application of environmental regulations and resources to all communities, especially small communities with declining populations on limited incomes, can result in costly upgrades or new construction, and onerous sampling, record keeping and reporting requirements. There may be better ways of assessing needs and maintaining or obtaining regulatory compliance.

Some basic questions are worth asking:

• What is and what will be the overall or comparative watershed impact from
• these small sources (or how can resources best be applied to meet environmental goals and achieve compliance with regulatory requirements)?
• Are all wastewater treatment options or combinations considered equally, or do funding source limitations restrict these choices?
• Can a risk-based approach to wastewater treatment be developed that would
• optimize available resources and still result in adequate and acceptable levels of environmental protection?
• How can wastewater treatment systems, centralized and decentralized, best be
• selected, funded and used consistently and appropriately in each situation?

No single method of wastewater treatment is the answer for all situations and this presentation is not intended to determine the most appropriate wastewater treatment method for any particular situation. However, the intent of the AWIN (Assessing Wastewater Infrastructure Needs) effort is to help develop, enhance and continue the discussion, look at a possible approach to provide a qualified assessment of infrastructure needs, and work towards solving the problem of how best to use available resources to meet wastewater infrastructure needs while providing adequate and appropriate environmental protection.

Control of Methane Emissions from Anaerobic Digestion

Anaerobic digestion from septic tanks or other sources give off gases, a large part of which is methane that is a greenhouse gas (GHG) 21 times more damaging than carbon dioxide.  Municipal systems can trap and reuse the methane but this is not practical for smaller systems.  Injection of the gases into the soil through a subsurface drip system will convert the methane to carbon dioxide thereby reducing the GHG damage by 95%; and furthermore, if there is vegetation on the surface the carbon dioxide will be taken up by this vegetation resulting in increased growth.  Studies by U.C. Davis (funded by WERF) and the California State University at Fresno will be referenced.

Onsite System Management without meaningful public involvement is like a septic tank without an effluent filter. Neither will work at peak efficiency and both will yield disappointing results.

Built on the experiences of a suburban municipality in central Pennsylvania, this presentation will detail the successful local policy development, citizen communications, and program implementation processes that resulted in an onsite system management program.  Roughly 1,200 onsite systems are covered in this program. Located in the land of the self-proclaimed, self-important, the elected officials successfully transferred more than 90% of the ongoing management program implementation costs to the landowners while achieving a 100% participation rate.  In the first three years of the program, no court actions were needed to achieve participation.

Basic principals of governmental leadership and program ownership, effective public communications and involvement, and a strong public-private linkage were the crisscrossing paths that led to success. Keeping government officials off residents’ land leveraged support and amplified acceptance.  Appealing to self interest, personal financial benefit and residents’ propensity toward frugality were key and intentionally unstated ingredients.

These concepts and their underlying principals can be used in any municipality where a potentially controversial public policy issue will be raised. When the intention is for there to be some sort of public intervention into what are held to be individual rights, the process described can overcome obstacles and garner support.

The goals of this program were repair/replace malfunctioning onsite systems, identify under performing systems for enhanced scrutiny, identify areas of concern where future sewer extensions may be needed, establish and continue a septic system focused communications program with landowners, and avoid costly state mandates.

This presentation will also detail program components which can benefit from a robust industry-government-public dialog.  For success, it is essential to remove all aspects of the  “I’m in it for my advantage” agenda. Weaknesses and missing links in current PA statute will be presented as they are likely missing elsewhere.

Fate and Transport of Onsite Wastewater Treatment System Derived Nitrogen in Coastal, North Carolina

A two year study (2009-2011) was conducted to assess the impacts that on-site wastewater systems (OSW) have on contributing nitrogen to water resources in coastal North Carolina. More specifically, soil water and shallow groundwater adjacent to two OSW, deeper groundwater from nearby water supply and/or irrigation wells, and estuarine waters were sampled and analyzed for both organic and inorganic nitrogen species. Nested piezometers were installed up and down-gradient of the on-site wastewater systems to allow for sampling groundwater at different depths beneath the water column. Multi-depth, suction lysimeters were installed up and down-gradient of the OSW for soil water sampling and analyses. The levels and quality of groundwater were monitored for 2 years. Various isotopic analyses were used to help quantify nitrogen concentration reduction processes. Results indicated that the concentration of nitrogen in soil water, shallow groundwater beneath and down-gradient from OSW were elevated relative to background wells. Nitrogen concentrations in shallow groundwater decreased with increasing distance from the OSW due to dilution, denitrification, and other processes. Nitrogen concentrations in existing irrigation wells (deeper than the monitoring piezometers) at sites 1 and 2 were similar to background levels. However, shallow groundwater down-gradient of OSW and near the estuary did contain elevated nitrogen concentrations. Above average rainfall was observed during the first year of study, leading to high water tables, while the second year had below average rainfall and deeper water tables. Organic and NH4 were the dominant N species during high water table periods, while NO3 was the dominant nitrogen species during periods of deeper water tables.

Onsite Economics

The amount of data that a typical county collects and manages can be staggering. Where onsite systems are concerned, it can appear time- and cost-prohibitive to administer a management program for onsite data effectively and pro-actively. In an era of ever-eroding funding sources, mandated septic programs are having difficulty getting started or staying afloat.  However, onsite system data is just that: data. Methods exist to help manage data efficiently and cost-effectively. Good data management can, in turn, generate more revenue, allow personnel to spend less time on repetitive clerical tasks, and facilitate a more prioritized, need-based response to problem systems.  This presentation will look at varying methods to approach revenue generation, management efficiencies and, once the program is in place, methods to measure its success.  Community differences dictate which methods are appropriate; however, each method requires technological support to provide the necessary efficiencies to run a streamlined program.   

Using the onsite programs of Napa County, California; Pierce County, Washington; and Lewis & Clark County, Montana, as examples, this presentation will illustrate how various management methods and technologies can be adapted and customized to a particular jurisdiction’s needs. Through the use of real data, the presenter will show how using technological tools and process improvements can increase administrative efficiencies, improve compliance for both consumers and service providers, and help regulators more effectively protect public health.                 

Performance evaluation of new onsite wastewater technologies – experiences with recycled media biofilters

A pretreatment system using media derived from the recycled husks of coconuts (100% coir fiber) was evaluated using 20 permanently occupied single-family residences located in the State of Virginia.  Sampling began in the summer of 2009 and continued to the summer of 2011.  Home locations ranged from the mountainous regions of western Virginia to sandy low relief sites on the Eastern Shore of Virginia.  Concentrations of biochemical oxygen demand, total suspended solids, and nitrogen species (TKN, nitrate + nitrite) were measured in system influent and effluent four times (once in each season) for each home.  Total phosphorus was measured from each home’s influent and effluent once during the study.  This paper provides information on the performance of this attached growth treatment system under real world conditions.                         

Measuring Gravity Sewer Flow Accurately

Flow measurement is a missing link in computing why septic systems may fail. Calculating the estimated flow on a sewer system can be impacted by inflow and infiltration issues. The actual flow may be further impacted with wet weather events and its impact may be ignored. Measuring flow should indicate a state of hydraulic overloading if evident in the performance of any septic or sewer system. The importance of knowing anticipated sewer flow can gauge potential problems. Daily flow can exceed the system design capacity, resulting in frequent sewer backups or puddling of sewage onto the ground surface.

Sanitary sewer overflows are evident in cases where potential problems are compacted with additional flows. Values for estimated sewage flows will be compared. Inflow and infiltration are often not considered when sizing an onsite wastewater system or sewer collection system. Ways to correct I&I will be shared. Several solutions to measure gravity sewer flow accurately will be discussed.