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Survey of the home sewage disposal systems in Northeast Ohio.

[ILLUSTRATION OMITTED]

Introduction

Water is arguably ar·gu·a·ble  
adj.
1. Open to argument: an arguable question, still unresolved.

2. That can be argued plausibly; defensible in argument: three arguable points of law.
 one of our most valuable resources, yet the quality of this resource remains a serious issue facing both the federal government and the state of Ohio, because these entities are challenged with the task of its protection. While we often think of waterborne diseases Waterborne diseases are caused by pathogenic microorganisms which are directly transmitted when contaminated drinking water is consumed. Contaminated drinking water used in the preparation of food can be the source of foodborne disease through consumption of the same microorganisms.  from contaminated contaminated,
v 1. made radioactive by the addition of small quantities of radioactive material.
2. made contaminated by adding infective or radiographic materials.
3. an infective surface or object.
 drinking water drinking water

supply of water available to animals for drinking supplied via nipples, in troughs, dams, ponds and larger natural water sources; an insufficient supply leads to dehydration; it can be the source of infection, e.g. leptospirosis, salmonellosis, or of poisoning, e.g.
 as being a problem for poorer countries or third world locations, from January 2003 to December 2004, 30 reported outbreaks occurred of waterborne diseases associated with contaminated drinking water in the U.S. (Centers for Disease Control and Prevention Centers for Disease Control and Prevention (CDC), agency of the U.S. Public Health Service since 1973, with headquarters in Atlanta; it was established in 1946 as the Communicable Disease Center.  [CDC See Control Data, century date change and Back Orifice.

CDC - Control Data Corporation
], 2006).

A critical part of protecting water quality is the appropriate collection, treatment, and disposal of domestic wastewater. Within the U.S., while most domestic wastewater management is a centralized system In telecommunications, a centralized system is one in which most communications are routed through one or more major central hubs. Such a system allows certain functions to be concentrated in the system's hubs, freeing up resources in the peripheral units.  (i.e., collection into sanitary sewers A sanitary sewer (also called, especially in the UK, a foul sewer) is a type of underground carriage system for transporting sewage from houses or industry to treatment or disposal.  and treatment at a wastewater treatment plant Wastewater treatment plant also called wastewater treatment works
  • Sewage treatment – treatment and disposal of human waste.
  • Industrial wastewater treatment – the treatment of wet wastes from manufacturing industry and commerce including mining, quarrying and
 that typically produces secondary or tertiary treated effluent effluent

waste from an abattoir carried away in liquid form. Disposal is a major problem because of the need to avoid pollution of waterways. See aerobic effluent treatment, anaerobic effluent treatment.
), about 25% of the country's population and 33% of new developments are served by decentralized de·cen·tral·ize  
v. de·cen·tral·ized, de·cen·tral·iz·ing, de·cen·tral·iz·es

v.tr.
1. To distribute the administrative functions or powers of (a central authority) among several local authorities.
, often individual onsite wastewater treatment systems (Siegrist et al., 2005; U.S. Environmental Protection Agency Environmental Protection Agency (EPA), independent agency of the U.S. government, with headquarters in Washington, D.C. It was established in 1970 to reduce and control air and water pollution, noise pollution, and radiation and to ensure the safe handling and  [U.S. EPA EPA eicosapentaenoic acid.

EPA
abbr.
eicosapentaenoic acid


EPA,
n.pr See acid, eicosapentaenoic.

EPA,
n.
], 2003). The U.S. EPA has found that such on-site treatment systems offer cost-effective alternatives for waste treatment and the protection of human health (U.S. EPA, 2002 and 2003).

Ohio does not vary from the national trend, with approximately 25% of Ohio's households being served by some type of onsite sewage treatment Sewage treatment

Unit processes used to separate, modify, remove, and destroy objectionable, hazardous, and pathogenic substances carried by wastewater in solution or suspension in order to render the water fit and safe for intended uses.
 systems (Ohio Department of Health [ODH ODH Ohio Department of Health
ODH Oxygen Deficiency Hazard
ODH Oklahoma Department of Health
ODH Off da Hook (hip hop song)
OdH Octopus Dofleini Hemocyanin
ODH Oracle Data Hub
], 2008). From 1979 to 2000, the most commonly installed system in Ohio was the septic septic /sep·tic/ (sep´tik) pertaining to sepsis.

sep·tic
adj.
1. Of, relating to, having the nature of, or affected by sepsis.

2.
 (anaerobic anaerobic /an·aer·o·bic/ (an?ah-ro´bik)
1. lacking molecular oxygen.

2. growing, living, or occurring in the absence of molecular oxygen; pertaining to an anaerobe.
) system with a soil adsorption adsorption, adhesion of the molecules of liquids, gases, and dissolved substances to the surfaces of solids, as opposed to absorption, in which the molecules actually enter the absorbing medium (see adhesion and cohesion).  field for ultimate treatment and disposal, accounting for approximately 75% of the total on-site, individual wastewater treatment systems (CT Consultants [CTC CTC - Cornell Theory Center ], 2001). This trend seems to be holding steady or slightly increasing according to according to
prep.
1. As stated or indicated by; on the authority of: according to historians.

2. In keeping with: according to instructions.

3.
 the Ohio Department of Health (ODH), which reported that between January 1 and June 30, 2007, 87% of systems installed were septic tanks septic tank, underground sedimentation tank in which sewage is retained for a short period while it is decomposed and purified by bacterial action. The organic matter in the sewage settles to the bottom of the tank, a film forms excluding atmospheric oxygen, and  discharging to soil absorption systems Absorption Systems is a company based in Exton, Pennsylvania that conducts contract research for the pharmaceutical industry with a focus on ADME analyses.  (ODH, 2008).

Onsite systems can also contribute to contamination of drinking water sources, however. U.S. EPA has estimated that as many as 168,000 viral illnesses and 34,000 bacterial illnesses occur each year from contaminated drinking water and that onsite sewage treatment systems (STS (Synchronous Transport Signal) The electrical equivalent of the SONET optical signal. In SDH, the European counterpart of SONET, STS is known as STM (Synchronous Transport Module). ) are one potential source of the contamination (U.S. EPA, 2002). Yet, despite the extensive use of onsite STS in Ohio, little knowledge currently exists about the actual failure rate of these systems; some states report failure rates as high as 50% to 70% (U.S. EPA, 2002). The only comprehensive survey of systems in Ohio reported in the literature was performed by Mancl (1990). That study, however, did not examine systems in the field, but rather surveyed county health departments to estimate failing systems, which was reported to be approximately 27% statewide (Mancl, 1990). In this article, we report on failure rates in onsite STS that were found as part of a comprehensive seven-county survey that was performed under the auspices of the Northeast Ohio Areawide Coordinating Agency (NOACA NOACA Northeast Ohio Areawide Coordinating Committee (Ohio) ) during the summer of 2000. A complete report on all aspects of the project, which included development of extensive databases, can be found in the NOACA Report (CTC, 2001). This paper focuses solely on the information collected on failing systems as part of the comprehensive report.

Materials and Methods

Definition of Failure

The ultimate goal of a home sewage disposal Sewage disposal

The ultimate return of used water to the environment. Disposal points distribute the used water either to aquatic bodies such as oceans, rivers, lakes, ponds, or lagoons or to land by absorption systems, groundwater recharge, and irrigation.
 system (HSDS HSDS High-Speed Data Switch
HSDS High Speed Dial-up Service (FTS2000)
HSDS High-Speed Digital System
HSDS Hawaii State Dressage Society
HSDS High Speed Data Services
HSDS Hierarchical Subdivision Surfaces
) is to treat and dispose of home wastewater by infiltration infiltration /in·fil·tra·tion/ (in?fil-tra´shun)
1. the pathological diffusion or accumulation in a tissue or cells of substances not normal to it or in amounts in excess of the normal.

2. infiltrate (2).
 into a soil system. Typically, design criteria Noun 1. design criteria - criteria that designers should meet in designing some system or device; "the job specifications summarized the design criteria"
criterion, standard - the ideal in terms of which something can be judged; "they live by the standards of their
 implemented by the counties through regulation are designed to ensure that systems are installed significantly above the water table to avoid groundwater contamination. While many factors can contribute to HSDS failure, soil unsuitability is often a primary cause (Canter canter

a gallop at an easy pace. The rhythm is three-time, first one hind, then the opposite hind with the diagonal fore, then the opposite fore, the leading limb.


collected canter
, 1985). Unfortunately, the majority of soil types in the northeast Ohio are classified as being severely limited for subsurface sub·sur·face  
adj.
Of, relating to, or situated in an area beneath a surface, especially the surface of the earth or of a body of water.

Adj. 1.
 disposal of effluent by the USDA USDA,
n.pr See United States Department of Agriculture.
 Soil Conservation Service. For example, out of 60 different soil types found in Geauga County, 95.0% are severely limited based on soil type, degree of slope, and depth to bedrock. Only 3.3% of the soil types are rated as being moderately limited, while the remaining 1.7% are classified as being only slightly limited (USDA, 1982). Hence, the issue of most concern to county health officials is failure of these systems through surfacing of wastewater. The goal of the study reported here, then, was to determine the percentage of systems in the seven-county area that were "failing" with respect to the elimination of the direct introduction of wastewater into surface waters.

In reality, failure of the system can occur in one of two modes. Either the system can fail to filter and biologically degrade TO DEGRADE, DEGRADING. To, sink or lower a person in the estimation of the public.
     2. As a man's character is of great importance to him, and it is his interest to retain the good opinion of all mankind, when he is a witness, he cannot be compelled to disclose
 the waste before it reaches the groundwater table, or the soil system becomes overloaded and wastewater rises to the surface. Because it was prohibitively expensive and practically impossible to drill wells, collect soil and groundwater samples, and analyze for various wastewater constituents (e.g., nutrients, coliform bacteria coliform bacteria

Rod-shaped bacteria usually found in the intestinal tracts of animals, including humans. Coliform bacteria do not require but can use oxygen, and they do not form spores. They produce acid and gas from the fermentation of lactose sugar.
) for the large number of systems across the seven counties involved in our survey, a system was identified as "failing" if, upon inspection, it had observable surfacing of effluent from the treatment system. For analyses, a system was identified as "surfacing" if surfacing effluent was seen.

Sampling Approach

Number of Systems to Investigate

On-lot systems represent approximately 70% of the total number of home sewage disposal systems present in the seven-county area. The remaining 30% discharge off lot and collect waste from a small group of homes, a small community, or a business. Because 700 total home sewage disposal systems were inspected during the project, we decided to inspect 490 on-lot systems to maintain the same percentage during inspections. The remaining 210 site visits were allocated to investigating off-lot systems and are not discussed further in this paper. As the project progressed, inclement in·clem·ent  
adj.
1. Stormy: inclement weather.

2. Showing no clemency; unmerciful.



in·clem
 weather and issues with access to some sites resulted in it not being possible to inspect all 490 targeted systems within the time frame allotted al·lot  
tr.v. al·lot·ted, al·lot·ting, al·lots
1. To parcel out; distribute or apportion: allotting land to homesteaders; allot blame.

2.
. For example, systems could not be inspected during or immediately after significant precipitation events, as it would not have been possible to distinguish failure (surfacing wastewater) from ponded precipitation. In addition, with the onset of winter, inspections of systems during freezing periods would have resulted in potentially biased data. Hence, we decided to only inspect systems from May through November, and consequently, we only inspected 427 total systems, distributed across the counties as follows: Cuyahoga (five systems), Geauga (93 systems), Lake (105 systems), Lorain (58 systems), Medina (one system), Portage Portage (1, 2 pôr`təj; 3 pôr`tĭj).

1 Town (1990 pop. 29,060), Porter co., NW Ind., a suburb of Gary, on Lake Michigan; inc. 1959.
 (78 systems), and Summit (87 systems). The location of the seven counties included in the survey is shown in Figure 1.

[FIGURE 1 OMITTED]

Grouping of On-Lot System Types and Controlling Variables

Because numerous system types and several potential controlling variables exist, it was not possible to develop a sampling scheme with 490 "samples" (number of on-lot system inspections initially planned to be performed) that would allow statistically and scientifically valid analyses of all potential contributors to system malfunction mal·func·tion
v.
1. To fail to function.

2. To function improperly.

n.
1. Failure to function.

2. Faulty or abnormal functioning.
. Therefore, based on the type of systems actually sampled, and after discussions with the County Health Department representatives, NOACA, and their consultant, we decided to focus on the effect of two control variables: oxygen status (aerobic vs. septic) and filtration (filter vs. no filter). The systems were grouped into four sets based on the two control variables. The resulting data parameters, estimated number of systems in each group, and the proposed and actual number of investigations performed are shown in Table 1. The data in Table 1 indicates that the inspection scheme resulted in a data set that satisfactorily approximates the distribution of the system types installed in the counties.

Field Survey

A certified soil scientist accompanied by a representative of the relevant local health district conducted each on-site investigation for this study. By having the same soil scientist do all surveys, consistency in methodology of assessing the site and determining if the system was surfacing were ensured throughout the seven-county area. In addition, the soil scientist was able to provide verification of soil types for each installation.

Statistical Methods

Confidence Intervals confidence interval,
n a statistical device used to determine the range within which an acceptable datum would fall. Confidence intervals are usually expressed in percentages, typically 95% or 99%.
 

During the investigation, on-lot systems were recorded as either surfacing or not surfacing. Similarly, off-lot systems were recorded as having poor effluent or not based on odor and color. To calculate a confidence interval, these "yes-no" answers were converted to 0s and 1s. It does not matter statistically what numerical values are used for "yes" and "no" because the statistical method normalizes for this selection. Standard practice, however, is to use 0 for "yes" and 1 for "no." This protocol was followed throughout the analyses in this report. Both the 95% and 90% confidence intervals are discussed below.

Significant Difference in Means

The sampling rationale and system grouping built into the survey design allowed comparative analyses to be conducted on the data collected from the inspected systems, as well as grouping system types to allow more robust statistical analyses. The grouping of the systems was designed to allow the analysis of the effect of aeration aeration /aer·a·tion/ (ar-a´shun)
1. the exchange of carbon dioxide for oxygen by the blood in the lungs.

2. the charging of a liquid with air or gas.


aer·a·tion
n.
 and filtration on system performance. The percentage of systems failing (i.e., surfacing) was compared across groupings using a standard t-distribution and comparison of the means (Box, Hunter, & Hunter, 1978). Difference is significant when

d > (ta/2) (s) = (1/na + 1/nb)1/2 (1)

where

d = absolute value of the difference between the means;

(ta/2) = t-value at desired confidence interval (90% used);

na and nb = number of samples in populations a and b, respectively; and

s = pooled standard error, calculated using Equation 2 (below) and

s = {[(na - 1)sa2 + (nb - 1)sb2]/ [(na - 1) + (nb - 1)]}1/2. (2)

Results and Discussion

Table 2 provides the total percentage of surfacing systems and the failure rates by control variable (system type and the 90% and 95% confidence intervals for each value). From the data, one can be 95% sure that at least 12.7% and as much as 19.7% (16.2% [+ or -] 3.5%) of all on-lot systems in the seven-county survey area met the definition of a surfacing system as defined in this study.

Table 3 shows the comparison of the data for various control variables. The data does not show any significant differences in the percentages of surfacing systems between any of the various groupings possible. This indicates that the addition or exclusion of either an aeration system or a filter to a home sewage disposal system does not significantly impact the probability of the system failing due to surfacing.

Effect of Soil Rating

The inspection team also verified soil classification and rating at the location of the on-lot systems inspected. Because soil type is considered to be a significant factor in on-lot system performance, it is of great interest to examine the differences in the percentages of systems surfacing in different soil types. Soil ratings and classifications were based on the USDA county surveys of soil types (Ernst, Musgrove, & Hayhurst, 1976; Hayhurst & Milleron, 1977; Musgrove & Holleran, 1980; Ritchie, Bauder, Christman, & Reese, 1978; Ritchie & Reider, 1979; USDA, 1982). It is important to note that the soil ratings and classifications found in the records at the various counties did not correspond completely with the reality found in the field. All analyses in this study were performed on soil ratings and soil classifications as verified during the inspections.

The data indicates that systems installed in severe soils have a significantly higher percentage of systems that were found to have surfacing effluent (23.3%) than the overall percentage of surfacing systems (16.2%) at the 95% confidence level. Even with a limited data set for non-severe soils, the data show that systems in "slightly inadequate" soils show a significantly lower percentage of surfacing systems (2.8%) at the 90% confidence level.

Because the severe soil classification represents 63% of the systems investigated, additional information on the parameters leading to a severe soil rating were also analyzed. A soil is rated as "severe" in the soil classification handbook for six reasons: a) excessive wetness (categorized cat·e·go·rize  
tr.v. cat·e·go·rized, cat·e·go·riz·ing, cat·e·go·riz·es
To put into a category or categories; classify.



cat
 as "wet"); b) slow permeability permeability /per·me·a·bil·i·ty/ (per?me-ah-bil´i-te) the property or state of being permeable.

per·me·a·bil·i·ty
n.
1. The property or condition of being permeable.

2.
 ("slow"); c) shallow bedrock ("shallow"); d) inappropriate slope; e) susceptibility to flooding; and f) susceptibility to ponding. Sufficient data existed to show soils that were rated as severe because they were wet, wet and slow, or wet, slow, and shallow with respect to the impact on the percentage of systems found to be surfacing. The data indicates that systems in soils that have any combination of excessive wetness, poor permeability, or shallow bedrock have a significantly higher probability of surfacing than systems in other soils rated "severe" by inspection (e.g., inappropriate slope, susceptibility to flooding, and susceptibility to ponding).

Effect of Soil Classification

Only those soil classifications in which at least 10 or more systems were investigated and in which the variance of the control variable (presence of surfacing effluent) was sufficiently low could be used to calculate reliable statistics on the percentage of surfacing systems. For five soils, sufficient data was collected to calculate reliable statistics. The results are provided in Table 4. The data reveals that those systems in Chili (language) CHILI - D.L. Abt. A language for systems programming, based on ALGOL 60 with extensions for structures and type declarations.

["CHILI, An Algorithmic Language for Systems Programming", CHI-1014, Chi Corp, Sep 1975]
 soils or soil complexes have a significantly lower percentage of failing systems at the 95% confidence interval. Out of 48 systems inspected in this soil type, none was reported as surfacing. Conversely, systems installed in either Mahoning or Ravenna soils (or soil complexes predominantly of these types) have a significantly higher percentage of trouble. Systems installed in Wadsworth soil or soil complexes have a significantly higher percentage of surfacing systems at the 90% confidence interval, but are not significantly different from the overall percentage at the 95% confidence level.

Effect of Inspection Date

Because numerous systems were inspected, a time factor existed in the inspection scheme. In addition, different weather patterns before an inspection (e.g., significant precipitation or lack thereof) could also have had an impact on the determination of whether or not effluent was surfacing in a given system. To examine the effects of the date of inspection, the systems were grouped by the month inspected, and the percentage of surfacing systems compared.

An analysis of the percentage of surfacing systems found during each month indicates that little effect occurred in the rate at which systems were identified as "surfacing" depending on the month in which the system was inspected. Only systems inspected in May were more likely to be identified as surfacing, and then only at the 90% confidence level. Because only about 5% of the total number of systems inspected were inspected in May, this difference does not represent an overall significant effect on the data collected.

Correlations between Selected Disposal System/Site Characteristics and Surfacing Effluent

During the investigation of on-lot systems, information on the number of bedrooms, tank volume, and other variables was collected. This data was used to determine whether systems that were found to be surfacing were more often associated with characteristics of the homes (e.g., number of bedrooms) or system design characteristics (e.g., tank size filter bed area, surface slope, and depth to ground water as indicated in as-builts). Sample correlation coefficients Correlation Coefficient

A measure that determines the degree to which two variable's movements are associated.

The correlation coefficient is calculated as:
 were calculated between comparison sets of data were calculated using Equation 3 as follows.

R([y.sub.1],[y.sub.2]) = S[([y.sub.i]-[y.sub.ave1])([y.sub.2]-[y.sub.ave2])]/(n-1)/[s.sub.1][s.sub.2] (3)

where

R([y.sub.1],[y.sub.2]) = the sample correlation coefficient between variable [y.sub.1] and [y.sub.2];

[y.sub.ave1] = average of variable [y.sub.1];

[y.sub.ave2] = average of variable [y.sub.2];

n = number of sample pairs; and

[s.sub.1] and [s.sub.2] = standard deviation In statistics, the average amount a number varies from the average number in a series of numbers.

(statistics) standard deviation - (SD) A measure of the range of values in a set of numbers.
 for variable 1 and 2, respectively (calculated by Equation 2).

The coefficient ranges between 1 and -1 and indicates if the two variables are more similar than would be expected if the two variables were completely independent. A sample correlation coefficient of 1 means the parameters are directly correlated and a coefficient of -1 indicates an inverse relationship A inverse or negative relationship is a mathematical relationship in which one variable decreases as another increases. For example, there is an inverse relationship between education and unemployment — that is, as education increases, the rate of unemployment . The closer the correlation coefficient is to either 1 or -1, the stronger the correlation between the two variables. It is important to understand, however, that correlation does not indicate causation causation

Relation that holds between two temporally simultaneous or successive events when the first event (the cause) brings about the other (the effect). According to David Hume, when we say of two types of object or event that “X causes Y” (e.g.
 but merely that the two variables appear related in the data. Table 5 shows the result of the analysis of correlations from the data.

Conclusion

This study represents a comprehensive survey of onsite home wastewater treatment systems in Northeast Ohio. The survey revealed several important facts about this method of wastewater treatment and disposal in the region. Most importantly Adv. 1. most importantly - above and beyond all other consideration; "above all, you must be independent"
above all, most especially
, the survey revealed that at least one in eight (12.7% and up to as many as one in five [19.7%]) of the onsite wastewater treatment systems are failing in that they are allowing wastewater to surface as opposed to infiltrate infiltrate /in·fil·trate/ (in-fil´trat)
1. to penetrate the interstices of a tissue or substance.

2. the material or solution so deposited.


in·fil·trate
v.
1.
. The rate of failure of these systems does not vary significantly between aerobic and septic systems or between systems with or without filters. Systems installed in soils rated as "severe" are significantly more likely to fail than those installed in soils having good or moderate ratings for wastewater introduction. Finally, while inconclusive INCONCLUSIVE. What does not put an end to a thing. Inconclusive presumptions are those which may be overcome by opposing proof; for example, the law presumes that he who possesses personal property is the owner of it, but evidence is allowed to contradict this presumption, and show who is  statistically, the study did tend to indicate that systems installed in areas with higher seasonal water tables were slightly more likely to fail.

Acknowledgements: The authors would like to acknowledge the support and cooperation of the Northeast Ohio Areawide Coordinating Agency (NOACA), CT Consultants, and the health departments of Cuyahoga, Geauga, Lake, Lorain, Medina, Portage, and Summit counties during the planning and execution of the work described in this paper. In addition, this study, and the larger project of which it was a part, could not have been accomplished without the active involvement and guidance of the Ohio Department of Health, the Ohio Environmental Protection agency, Cleveland State University Cleveland State University, at Cleveland, Ohio; coeducational; founded 1964, incorporating Fenn College (est. 1923). The Cleveland-Marshall School of law was incorporated in 1969. , and local health department officials.

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Box, G.E.P., Hunter, W.G., & Hunter, J.S. (1978). Statistics for experimenters: An introduction to design, data analysis, and model building. New York New York, state, United States
New York, Middle Atlantic state of the United States. It is bordered by Vermont, Massachusetts, Connecticut, and the Atlantic Ocean (E), New Jersey and Pennsylvania (S), Lakes Erie and Ontario and the Canadian province of
: John Wiley John Wiley may refer to:
  • John Wiley & Sons, publishing company
  • John C. Wiley, American ambassador
  • John D. Wiley, Chancellor of the University of Wisconsin-Madison
  • John M. Wiley (1846–1912), U.S.
 & Sons.

Canter, L.W., & Knox, R.C. (1985). Septic tank system effects on ground water quality. Chelsea, MI: Lewis Publishers.

Centers for Disease Control and Prevention. (2006). Surveillance for waterborne disease outbreaks associated with drinking water and water not intended for drinking in the United States United States, officially United States of America, republic (2005 est. pop. 295,734,000), 3,539,227 sq mi (9,166,598 sq km), North America. The United States is the world's third largest country in population and the fourth largest country in area. , 2003-2004. Morbidity and Mortality Weekly Report Morbidity and Mortality Weekly Report (MMWR) is a weekly epidemiological digest for the United States published by the Centers for Disease Control and Prevention. The 5 June 1981 issue of the MMWR published the cases of five men in what turned out to be the first report of AIDS. , 55(SS-12), 31-58.

CT Consultants, Incorporated. (2001). Survey of northeast Ohio home sewage disposal systems and semi-public sewage disposal systems. Willoughby, OH: Author.

Ernst, J., Musgrove, D.K., & Hayhurst, E.N. (1976). Soil survey of Lorain County, Ohio Lorain County is a county located in the U.S. state of Ohio, and is considered to be a part of what is locally referred to as Greater Cleveland. As of the 2000 census, its population is 284,664. . Washington, DC: U.S. Department of Agriculture Soil Conservation Service.

Hayhurst, E.N., & Milleron, E.L. (1977). Soil survey of Medina County, Ohio Medina County is a county located in the state of Ohio, United States. As of the 2000 census, the population was 151,095. The 2004 projected population was estimated at 165,370. . Washington, DC: U.S. Department of Agriculture Soil Conservation Service.

Mancl, K. (1990). A survey of small sewage treatment facilities in Ohio. Ohio Journal of Science, 90(4), 112-117.

Musgrove, D.K., & Holleran, P.M. (1980). Soil survey of Cuyahoga County, Ohio Cuyahoga County (IPA pronunciation: ˌkaɪəˈhɔgə)[2] is a county located in the state of Ohio, United States. . Washington, DC: U.S. Department of Agriculture Soil Conservation Service.

Ohio Department of Health. (2008). Report to the household sewage and small flow on-site sewage treatment system study commission, January 1, 2008. Columbus, OH: Author.

Ritchie, A., & Reider, N.E. (1979). Soil survey of Lake County, Ohio Lake County is a county located in the U.S. state of Ohio. As of 2000, the population was 227,511. The county seat is Painesville6, and the county name comes from its location on the southern shore of Lake Erie.[2] Geography
According to the U.S.
. Washington, DC: U.S. Department of Agriculture Soil Conservation Service.

Ritchie, A., Bauder, J.R., Christman, R.L., & Reese, P.W. (1978). Soil survey of Portage County, Ohio Portage County is a county located in the U.S. state of Ohio. As of 2000, the population was 152,061. Its county seat is Ravenna6. Portage County is named for the portage between the Cuyahoga and Tuscarawas Rivers. . Washington, DC: U.S. Department of Agriculture Soil Conservation Service.

Siegrist, R.L., McCray, J., Weintraub, L., Chen, C., Bagdol, J., Lemonds, P., Van Cuyk, S., Lowe, K., Goldstein, R., & Rada, J. (2005). Quantifying site-scale processes and watershed-scale cumulative effects of decentralized wastewater systems (Project No. WU-HT-00-27, prepared for the National Decentralized Water Resources Capacity Development Project, Washington University Washington University, at St. Louis, Mo.; coeducational; est. as Eliot Seminary 1853, opened 1854, renamed 1857. It has a well-known medical school and school of social work as well as research centers for radiology, space studies, engineering computing, and the , St. Louis, MO). Golden, CO: Colorado School of Mines Colorado School of Mines, at Golden; state supported, coeducational; chartered 1874. It was one of the first mineral engineering schools in the United States. .

U.S. Environmental Protection Agency. (2002). Onsite wastewater treatment systems manual (Report No. EPA 625/R-00/008). Washington, DC: Author.

U.S. Environmental Protection Agency. (2003). Voluntary national guidelines for management of onsite and clustered (decentralized) wastewater treatment systems (Report No. EPA 832-B-03-001). Washington, DC: Author.

U.S. Department of Agriculture and Ohio Department of Natural Resources Many sub-national governments have a Department of Natural Resources or similarly-named organization:
Australia
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Canada
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. (1982). Soil survey of Geauga County, Ohio Geauga County is a county located in the state of Ohio, United States. As of 2000, the population was 90,895. It is named for a Native American word meaning "raccoon". The county seat is Chardon6.[2] Geography
According to the U.S.
. Washington, DC: U.S. Department of Agriculture Soil Conservation Service.

Mark A. Tumeo, PhD, JD, PE

Juliet Newland, MS, PE

Corresponding Author: Mark A. Tumeo, Professor, Civil and Environmental Engineering, Cleveland State University, Department of Civil and Environmental Engineering, 2121 Euclid AVE (SH 119), Cleveland, OH 44115. E-mail: m.tumeo@csuohio.edu.
TABLE 1
Grouping of On-Lot Systems for Data Analyses

                                          Total
           Control                      Installed      % of Total
Type       Characteristics              (Estimate)     Installed

A          Anaerobic with filter           4381           13.9%
B          Anaerobic without filter       23559           74.7%
C          Aerobic with filter             1438            4.6%
D          Aerobic without filter          2165            6.9%
Totals                                    31543          100.0%

           Targeted for          Actual          % of Total
Type       Investigation     Investigations     Investigated

A                24                52               12.2%
B               408               318               74.5%
C                25                24                5.6%
D                33                33                7.7%
Totals          490               427              100.0%

TABLE 2
Percentage of Surfacing On-Lot Systems

                                          Confidence       No. of
System Type                    %           Interval        Samples

                                        95%       90%

Anaerobic with filter        19.2%     11.1%      9.3%        52
Anaerobic without filter     15.1%      3.9%      3.3%       318
Aerobic with filter          12.5%     14.3%     11.8%        24
Aerobic without filter       24.2%     15.4%     12.8%        33
All anaerobic (A+B)          15.7%      3.7%      3.1%       370
All aerobic (C+D)            19.3%     10.6%      8.8%        57
Overall                      16.2%      3.5%      2.9%       427

TABLE 3
Comparison of Surfacing Percentages Between System Groups

  Anaerobic Systems
     w/o Filters        All Other Systems            Results

    %       No. of        %       No. of
Surfacing   Samples   Surfacing   Samples

 15.10%       318      19.30%       109     No significant difference
                                            between groups

  Anaerobic systems      Aerobic systems
     w/o filters           w/o filters

    %       No. of        %       No. of
Surfacing   Samples   Surfacing   Samples

 15.10%       318      12.50%       24      No significant difference
                                            between groups

   Aerobic systems       Aerobic systems
     w/ filters            w/o filters

    %       No. of        %       No. of
Surfacing   Samples   Surfacing   Samples

 24.20%       33       12.50%       24      No significant difference
                                            between groups

     All systems           All systems
     w/o filters           w/ filters

    %       No. of        %       No. of
Surfacing   Samples   Surfacing   Samples

 16.00%       351      17.10%       76      No significant difference
                                            between groups

     All aerobic          All anaerobic
       systems               systems

    %       No. of        %       No. of
Surfacing   Samples   Surfacing   Samples

 19.30%       57       15.70%       370     No significant difference
                                            between groups

TABLE 4
Percentages of Surfacing Systems in Different Soil Types

                                          Confidence    No. of
Soil Type                        %         Interval     Samples

                                         95%     90%

Overall                        16.20%   3.50%   2.90%     427

Chili (and complexes)            0.0%    0.0%    0.0%      48

Ellsworth                       15.8%   12.2%   10.1%      38

Mahoning (and complexes)        27.7%    9.2%    7.7%      94

Platea (and Platea-Mahoning)    30.0%   22.0%   18.2%      20

Wadsworth (and complexes)       31.8%   21.1%   17.5%      22

Ravenna (and complexes)         45.5%   35.1%   28.5%      11

Soil Type                      Comparison

Overall

Chili (and complexes)          Significantly lower than the overall
                               percent surfacing at the 95% confidence
                               level.

Ellsworth                      Not significantly different than
                               overall.

Mahoning (and complexes)       Significantly higher than the overall
                               percent surfacing at the 95% confidence
                               level.

Platea (and Platea-Mahoning)   Not significantly different than
                               overall.

Wadsworth (and complexes)      Significantly higher than the overall
                               percent surfacing at the 90% confidence
                               level.

Ravenna (and complexes)        Significantly higher than the overall
                               percent surfacing at the 95% confidence
                               level.

TABLE 5
Correlations in Overall On-Lot Inspection Data

                      Number
                      of Data   Correlation
Correlation Between    Pairs    Coefficient   Interpretation

Number of bedrooms      394        0.086      No significant
and surfacing                                 correlation between
systems                                       these two variables.

Tank volume and         350        0.085      No significant
surfacing systems                             correlation between
                                              these two variables.

Filter area and          62       -0.056      No significant
surfacing systems                             correlation between
                                              these two variables.

ET area and              53        0.178      No significant
surfacing systems                             correlation between
                                              these two variables.

Slope and surfacing     422        -0.09      No significant
systems                                       correlation between
                                              these two variables.

Minimum depth to        368       -0.217      Slightly correlated,
groundwater and                               as minimum depth to
surfacing systems                             groundwater increases,
                                              the probability of
                                              system being identified
                                              as surfacing decreases.

Runoff received and     427        0.043      No significant
surfacing systems                             correlation between
                                              these two variables.

Landscape position      420        0.118      No significant
and surfacing                                 correlation between
systems                                       these two variables.

Trench length and       358        0.131      No significant
surfacing systems                             correlation between
                                              these two variables.
COPYRIGHT 2009 National Environmental Health Association
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Author:Tumeo, Mark A.; Newland, Juliet
Publication:Journal of Environmental Health
Article Type:Cover story
Date:Sep 1, 2009
Words:4041
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