Summer 2013 Vol 24, No. 1

Small Community Wastewater Issues Explained to the Public and Onsite Wastewater Systems

In the previous Pipeline we discussed the role of nitrogen in onsite wastewater systems, its effect on the environment, and how to reduce nitrogen discharges. In this issue of Pipeline we discuss phosphorus, the other major nutrient of concern found in residential wastewater, and what hap- pens to phosphorus in the environment and in onsite wastewater systems. Phosphorus has not generally been considered to be a major problem for onsite systems. However, because of the site-specific nature of onsite wastewater treatment, in some cases it does create problems. This Pipeline discusses situations where and why it may be a problem and what the options are for controlling phosphorus.

Phosphorus and the in nature. Phosphorus atoms of phosphorus occurs both in environment: frequently combine with three terrestrial and aquatic envi- oxygen atoms to form a com- ronments—animals consume The back story posite ion with a plants containing phosphorus negative three charge. The hosphorus is an and excrete wastes containing phosphate ion can then com- phosphorus that then becomes essential nutrient bine with other atoms and for sustaining all available for use by other molecules to form a variety of plants, animals, and microbes. P life and is pres- compounds. We often use the ent in every cell terms phosphorus and phos- Ultimately, phosphorus ends in every living organism. It phate interchangeably but a is an indispensable part of up in the where, after phosphorus atom is a part of more biological the important, but generally the phosphate ion. underappreciated, molecule, which As with carbon and nitrogen, stores energy and releases it phosphorus has a natural as needed for cellular activ- cycle in the environment. It ity. Phosphorus is also a key is present in rocks and in component in the structure the . As rocks weather, of DNA. In vertebrates phos- phosphorus is released phorus is found in teeth that becomes available and bones. It is one of the for incorporation into soil major nutrients necessary for and for uptake by plants. healthy plant growth, where it Phosphorus in soil that plays key roles in photosyn- is not taken up by plants thesis and a variety of other is subject to by functions such as healthy root both wind and rain, and development and seed forma- eventually finds its way tion. into streams and rivers in a dissolved form or as Because of its high chemical components of suspended reactivity, phosphorus is rare- sediment. Consider- ly found in its elemental state able biological Phosphorus and Onsite Wastewater Systems

recycling by marine plank- the phosphorus cycle is much, ton and other organisms, it much slower than either the is deposited on the carbon or the . floor. Over periods of mil- This is at least partly because lions of years ocean sedi- phosphorus does not ments become compressed naturally exist in a and consolidated into layers of gaseous state to any rock. These ocean-floor rock significant extent. As layers eventually are subject a result there is no to geologic uplift into above- atmospheric cycling sea-level mountains that are of phosphorus again subject to between the terrestrial and erosion, completing the and marine environ- cycle. Because we are talking ments as there is with about geologic time scales, carbon and nitrogen.

The key role of phosphorus in enhancing plant growth was scientifi- cally verified less than 200 years ago. Before that farmers, without knowing into a one-way transfer of exactly how or why it helped, phosphorus from the land to had learned to add substances the ocean bottoms. The phos- Pipeline is published by the National Environmental Services Center that contained phosphorus to phorus is not destroyed, but it at West Virginia University, croplands. Historically these is dispersed to the ocean floor P.O. Box 6893, Morgantown, WV 26506-6893 were mainly animal manures, where recovery is economically plant residues, or human not feasible. PipelineLVIXQGHGE\WKH86'HSDUWPHQWRI$JULFXOWXUH·V waste products. Within the last Rural Development Rural Utilities Service, whose mis- sion is to serve in a leading role in improving the qual- 100 years, however, the min- Because the easily accessible, ity of life in rural America by administering its electric, ing of phosphate-bearing rock high-quality phosphate rock telecommunications, and water and waste programs in a deposits that are then indus- deposits are being depleted service-oriented, forward-looking, and financially respon- trially processed has been the there have been discussions in VLEOH PDQQHU )RXQGHG LQ  DV WKH )DUPHU·V +RPH Administration, Rural Development Rural Utilities Service main source of agricultural the past 10 years of phospho- has provided more than $40 billion for water and waste- phosphorus . About rus production peaking and water projects. For more information, visit their website at 80 to 90 percent of the mined declining, which raises con- www.usda.gov/rus/. phosphate rock is made into cerns about the ability to keep with the remainder the world fed. Others believe Joyce Taylor, RUS Loan Specialist and Project Officer being used in food and bev- that new deposits of phos- U.S. Department of Agriculture’s erages, detergents, indus- phorus will be discovered and Rural Development Rural Utilities Service trial processes, and animal made available averting any Office of Wastewater Management feeds. The availability of mass potential global food security National Enviromental Services Center amounts of phosphate fertil- crisis. It is likely, however, West Virginia University, Morgantown, WV izer contributed to the “Green that newly discovered depos- Dr. Gerald Iwan — Executive Director Revolution” that dramatically its will require more energy to Mark Kemp — Communications Manager / Editor increased global food produc- mine, process, and purify. As Craig Mains — Author/Technical Advisor tion, in turn allowing global a result, regardless of it rela- Zane Satterfield — Technical Advisor John Fekete — Senior Project Coordinator population to increase from tive availability, phosphorus is about 1.6 billion people in expected to become a more Permission to quote from or reproduce articles in this publication is granted when due acknowledgement is given. 1900 to more than seven bil- expensive resource in the near Please send a copy of the publication in which information lion people today. future. was used to the Pipeline editor at the address above. Some images in this issue obtained from www.Thinkstock.com. However, because phosphate As with nitrogen, the dramatic rock deposits are formed only increase in the agricultural use over long geologic time peri- of phosphorus during the past an equal opportunity/affirmative action institution ods, from the human perspec- 100 years has brought some ISSN 1060-0043 tive, phosphorus is a finite unintended, negative conse- The contents of this newsletter do not necessarily reflect the views and policies of the United States Department of Agriculture, nor does the mention of trade names resource that is being rapidly quences. Phosphorus is not a or commercial products constitute endorsement or recommendation for use. consumed. Accelerated min- selective fertilizer. When soil ing and consumption of phos- that contains phosphorus is phate rock have essentially eroded by wind or rain, phos- turned the phosphorus cycle phorus ends up in streams 2

PIPELINE – Summer 2013; Vol. 24, No. 1 National Environmental Services Center (800) 624-8301 or (304) 293-4191 Phosphorus and Onsite Wastewater Systems

and lakes where it can stimu- the U.S. in the last 20 years. taking place. Concentrations late biological activity beyond Because cyanobacteria can fix of total phosphorus in the normal levels, a condition nitrogen from the atmosphere, range of 0.02 to 0.03 mg/l referred to as . they can bloom in water bod- have been shown to stimulate This often results in the over- ies that are low in nitrogen if algal growth in many North abundant growth of undesir- sufficient phosphorus is pres- American freshwater lakes. ent. The toxins can be ingest- able algae, referred to as a ed by swimmers and boaters harmful . In the 1960s, widespread eutrophication of lakes and rivers attributed to phosphate became a public concern leading to 27 states passing full or partial bans on laundry detergents containing phosphate. Detergent manu- facturers voluntarily phased out the use of in laundry detergents nation- ally in 1994. More recently, attention has focused on dish- washer detergents containing phosphates. Because auto- matic dishwashers were not as common in the 1960s, dish- washer detergents were not included in the initial bans. In response to 16 states pass- ing bans limiting phosphates in dishwashing detergents, in 2010 the detergent industry greatly reduced the use of phosphates in domestic dish- The frequency and severity of harmful washer detergents nationally algal blooms in lakes and rivers is increas- from 8.7 percent to no more ing globally. than 0.5 percent. Phosphates are still present in consumer products such as some hair Undesirable or harmful algal dyes, toothpastes, mouth blooms create a number washes, liquid hand soaps, of problems besides being and shampoos. unsightly. Individual algae are short-lived and as they Although phosphate bans and who are in direct contact with die and decompose they con- other actions taken to control the water. However, under sume dissolved oxygen. Low- phosphate have helped, the certain conditions the toxins oxygen conditions, referred continued application of phos- can also become aerosolized to as hypoxia, can lead to fish phate fertilizers and animal and inhaled by others at a dis- kills, loss of other aquatic life, manures along with popula- tance from their source. The and noxious conditions. Algal tion growth means that phos- toxins can be removed from blooms can also shade out phate contamination continues drinking water sources but at native rooted aquatic plants to be an issue. Currently, the an added cost. and negatively shift the eco- U.S. Environmental Protection

logical balance in aquatic Agency estimates more than It is generally accepted that environments. 100,000 miles of streams; phosphorus is usually the lim- about 2.5 million acres of iting nutrient when it comes lakes, reservoirs, and ponds; Certain types of algae called to eutrophication of freshwa- and 800 square miles of bays cyanobacteria, also referred to ter resources and nitrogen is and estuaries have poor water as blue-green algae, produce usually the limiting nutrient in quality due to excess nutrients potent toxins that are harm- offshore waters and estuar- including phosphorus. ful to humans and aquatic life. ies. The limiting nutrient is the Blooms of cyanobacteria have nutrient in least supply relative become increasingly more fre- to its demand and controls the quent in freshwater lakes in amount of biological growth 3 PIPELINE – Summer 2013; Vol. 24 No 1. National Environmental Services Center (800) 624-8301 or (304) 293-4191 Phosphorus and Onsite Wastewater Systems

excreted varies from per- son to person depending on diet and other factors. The approximately two-to-one ratio between the amount of phosphorus found in urine to that in feces, however, is fairly consistent.

On a national basis the major- ity of phosphorus released to the environment by human activity comes from agricul- ture. Current data are not available. However, a 1984 study estimated that 72 per- cent came from agriculture, split evenly between fertilizer This satellite image shows the extent of a blue-green algae bloom in the western sec- application and manure appli- tion of Lake Erie in 2011. An unusually wet spring, which generated high levels of cation. Five percent came from nutrients in runoff, followed by warmer weather contributed to the worst algal bloom wastewater treatment plants in Lake Erie since the 1960s. and the remaining 22 percent Photo credit: MERIS/NASA; processed by NOAA/NOS/NCCOS came from all other non-point sources, including onsite Phosphorus in sured as total phosphorus, wastewater systems. which includes both inorganic Wastewater and organic forms of phos- Agriculture and domestic phorus. The concentration wastewater are closely con- Phosphorus in wastewater is of total phosphorus in raw nected when it comes to categorized as either inor- wastewater is quite variable phosphorus. Phosphorus ganic or organic phosphorus. from household to house- applied by farmers ends up in Inorganic phosphorus includes hold. A 2008 survey of 17 the foods we eat. Any excess relatively simple forms of residences in three regions of SKRVSKRUXVRXUERGLHVGRQ·W phosphates referred to as the U.S. found total phospho- need is excreted and ends up reactive or ortho-phosphates rus concentrations ranging in our wastewater. Our waste- consisting of one phosphate from 0.2 to 32 mg P/l with a water is now being viewed by ion and zero to three hydro- median value of 10.4 mg/l. many as a potential source of gen ions, depending on the A 1991 study estimated that phosphate and other nutrients pH level. Condensed phos- the average person in the US to be recycled for agricultural phates or polyphosphates, generates about 2.7 grams use. As the availability of eas- also categorized as inorganic, of phosphorus per day with ily mined, high-quality rock are somewhat more complex approximately 59 percent of phosphate declines and the chemical structures with more the phosphorus coming from need to make agriculture more than one phosphorus atom toilets; 37 percent from sinks, sustainable becomes more linked together in each mol- showers, and appliances; and apparent, wastewater will ecule. Most polyphosphates four percent from kitchen increasingly be seen more as originate in detergents and garbage disposals. Due to the a resource and less as a waste other cleaning products and 1994 ban on phosphates in product. eventually decompose into laundry detergents and the ortho-phosphates. Organic 2010 ban affecting dishwash- What happens to phosphorus includes phos- ing detergents the average phorus incorporated into amount generated per per- phosphorus in onsite undigested food residue and son has decreased and it has wastewater systems? dead and living bacteria that been estimated that as much are present in feces. Some as 75 percent of phosphorus The concern with phospho- organic phosphorus is also may now be contained in toilet rus in onsite systems is that present in uneaten food scraps wastewater. the concentration of phos- that are part of the wastewater phorus in wastewater is usu- stream. For toilet wastes, approxi- ally hundreds of times higher mately two-thirds of the than that needed to stimu- Phosphorus in water and phosphorus is contained late algal growth in surface wastewater is typically mea- in urine, with the remain- water. Fortunately, compared der found in feces. The to other wastewater constitu- 4 total amount of phosphorus

PIPELINE – Summer 2013; Vol. 24, No. 1 National Environmental Services Center (800) 624-8301 or (304) 293-4191 Phosphorus and Onsite Wastewater Systems

ents, phosphorus is not very As the wastewater leaves the careous tend to be acidic mobile. In most cases, phos- septic tank and is dispersed to rather than alkaline. Cations phorus is effectively retained the unsaturated soil beneath such as iron and aluminum in the soils below drainfields the drainfield, phosphorus is that can react effectively with (or soil absorption systems), retained due to two chemi- phosphate are generally more preventing much phospho- cal processes: precipitation available in non-calcareous rus from being released to and adsorption. Precipita- soils. Although phosphate streams and lakes. As a result tion occurs when negatively reacts with calcium in calcar- phosphorus from onsite charged phosphate anions eous soils, it is more effec- wastewater systems has his- react chemically with posi- tively immobilized by iron and torically been lightly regu- tively charged cations to form aluminum in non-calcareous lated and added treatment for a solid mineral that is immo- soils. phosphorus reduction is still bilized in the soil. Common rare. The science underlying cations that react with phos- The other way phosphate how phosphorus is retained by phate to form minerals are is immobilized is through soils, however, is complex and iron (both Fe+2 and Fe+3), adsorption. Adsorption occurs varies with soil types. aluminum (Al+3), and calcium when phosphate anions are (Ca+2). Phosphate also reacts attracted to and bind to posi- Some phosphorus is removed with oxides of iron, aluminum, tively charged mineral particle as the wastewater flows and calcium to form stable surfaces. Binding by adsorp- through the septic tank. Some phosphate-metal complexes. tion is not as strong as pre- studies have estimated that as cipitation reactions and is much as 20 to 30 percent of The extent to which precipita- considered more reversible. phosphorus becomes part of tion occurs in soil depends on Adsorption is limited by the the settled solids in the septic a number of factors including number of adsorption sites tank. A 2008 study indicated soil pH, the oxidation/reduc- available. The capacity for less than six percent removal tion status of the soil, the precipitation is also finite but of phosphorus occurs in septic relative availability of cations can continue as long as cat- tanks, however. The concen- to react with phosphate, and ions are available and there is tration of total phosphorus in whether a soil is calcareous or space in the soil for the pre- septic tank effluent, the liquid non-calcareous. Calcareous cipitating solid. exiting the septic tank, var- soils are soils of marine origin ies widely from household to that have a significant calcium As with precipitation, adsorp- household but the median carbonate content and tend to tion is more effective in acidic value is approximately 10 be alkaline in nature. Non-cal- environments than alkaline mg/l. environments. Adsorption

Phosphorus Rapid Trenches Attenuation Zone

Septic Tank

P P P P P P P Cl- P N0 - 3 P P P N0 - Cl- 3 Cl- N0 - N0 - N0 - 3 Cl- 3 3 Cl- N0 - N0 - 3 3 N0 - Water Table 3 Cl- N0 - Cl- 3 Cl- N0 - 3

In many onsite wastewater systems, phosphorus (P) is effectively immobilized within the first two or three feet of soil below drain- field trenches. This area has been referred to as the Phosphorus Rapid Attenuation Zone or Phosphorus Enrichment Zone. This is in - - contrast to the plume associated with other more mobile wastewater constituents such as nitrate (NO3 ) and chloride (Cl ). The - - extent of movement of phosphorus varies from system to system but is almost always less than that of NO3 and Cl . 5 PIPELINE – Summer 2013; Vol. 24 No 1. National Environmental Services Center (800) 624-8301 or (304) 293-4191 Phosphorus and Onsite Wastewater Systems

relies on negatively charged • Coarse-grained soils such as Source Diversion phosphate anions being sandy and gravelly soils that attracted to positively charged allow rapid flow rates; Because 60 to 75 percent of surfaces including aluminum phosphorus is contained in and iron oxides and hydrox- • Households that gener- toilet wastewater, referred ides and clay minerals. The ate more wastewater than to as blackwater, remov- surface charge of the minerals their septic systems were ing the blackwater from the can vary under different con- designed to handle; wastewater stream can greatly ditions. In alkaline conditions, • Drainfields with thin soils, reduce the amount of phos- such as in calcareous soils, shallow bedrock, or high phorus discharged from an the net surface charge is more water tables; onsite system. This has been likely to be negative in which achieved through the use of case little or no adsorption is • Systems with drainfields composting toilets, urine- likely to occur. close to lakes or streams; diverting toilets, and holding • Areas where onsite systems tanks. The remaining waste- Precipitation and adsorption are densely sited; water in the household from quickly and effectively retard other fixtures goes to the the movement of phosphorus • Systems where the septic septic system or a grey water in many drainfield soils to the tank effluent is not uni- system. extent that there is a zone formly distributed across the of phosphorus enrichment drainfield; or Composting toilets collect or accumulation within the • Older or substandard sys- toilet waste in a chamber first meter below the drain- tems such as cesspools, below the toilet. The system field lines. This zone, which which may be in direct con- is designed so that the con- includes the biomat, has been tact with groundwater during tents compost or decompose referred to as the Phosphorus part of the year. biologically into a humus- Rapid Attenuation Zone. like material that needs to be removed periodically. There Problem areas often occur due Precipitation and adsorption are a wide variety of models to the combination of multiple are less effective once any of composting toilets avail- factors. For example, numer- remaining phosphorus reaches able including ones that use ous lake-front communities groundwater. The movement a small amount of flush water with closely sited homes, with of phosphorus in groundwater and are able to evaporate off drainfields in sandy or gravelly is still slower however than any excess liquid that might soils close to the lake shore the movement of more mobile, interfere with the compost- have experienced problems less reactive anions such as ing process. Because most with noxious algal blooms. In nitrate and chloride. Studies composting toilets capture cases such as these, where that have plotted the move- all of the blackwater they can drainfield soils are not capable ment of groundwater plumes potentially remove as much as of immobilizing phosphorus, of septic system contaminants 75 percent of the phosphorus, some additional action may be almost always show a con- necessary in order to restore siderably longer plume for The fully composted material lake water quality. nitrates and chlorides com- must occasionally be removed pared to phosphate, even in by a service provider or the situations where conditions for Phosphorus homeowner. Some states have phosphate immobilization may Reduction Options rules regarding the accept- not be ideal. The extent to able disposal of the compos- which phosphorus migration is ted material. Appropriate use A number of options can or disposal of the compost is retarded is variable and site- be used in situations where specific. necessary so that the phos- phosphorus from onsite phorus problem is not simply wastewater systems has been Nevertheless, there are cir- transferred from one location identified as a problem. These to another. cumstances where phosphorus options can be categorized from onsite wastewater sys- as source diversion, advanced Urine-diverting toilets remove tems can contribute to pollu- treatment, and drainfield tion of lakes or streams. Some urine from the wastewater modifications. Because con- stream to then be disposed of the factors that contribute cern with phosphorus from to problem sites include: of separately. These toilets onsite wastewater systems are constructed with a bar- • Calcareous soils; is fairly recent treatment rier in the bowl that separates approaches are continuing to urine from solid toilet waste. evolve.

6

PIPELINE – Summer 2013; Vol. 24, No. 1 National Environmental Services Center (800) 624-8301 or (304) 293-4191 Phosphorus and Onsite Wastewater Systems

Urine is deposited in the systems are still uncommon manufactured, and industrial front chamber and feces in the U.S., a number of units by-products. Natural media and toilet paper in the rear are available commercially. A include iron-rich soils and chamber. The front cham- variety of approaches to phos- peat, which may be supple- ber has a separate line that phorus reduction have been mented with additional mate- allows urine to be collected made but the most common rials to increase their affinity in a storage tank. The urine method has been through the for phosphorus. Other natural can be processed for use use of reactive media filters. materials that have been test- as either a liquid or a solid These are modular units that ed include limestone, bauxite fertilizer. Because urine con- are installed between the sep- (aluminum ore), bentonite (a tains about two-thirds of tic tank and the drainfield. type of clay), and lignocellu- the phosphorus in blackwa- lose fibers, among others. ter, urine diversion has the Media filters, such as sand potential to remove 35 to 50 or gravel filters, have been Manufactured materials percent of phosphorus from used for decades to provide include light-weight clay residential wastewater. The an additional level of waste- aggregates, which have been effectiveness of the toilet water treatment for onsite processed to expand the clay at diverting urine depends systems. The difference with structure to provide greater upon the correct use of the phosphorus removal systems surface area. Phosphorus toilet by the users. is that a medium or combina- removal for systems using

Urine-diverting toilets are not common in the U.S. at this time. However, they have been successfully used in other countries, particu- larly in planned communi- ties in Europe. Their use in the U.S. has been limited by their unfamiliarity and the lack of a well-established system to collect, process, and reuse the urine agricul- turally. However, urine har- vesting is beginning to draw more interest in the U.S. and this is expected to increase as the benefits of captur- ing the nutrients in urine for agricultural use becomes more evident.

In some cases, households may be permitted to divert Separating urine from the wastewater of residences or public facilities through their toilet waste to a hold- the use of urine-diverting toilets or urinals can potentially reduce phosphorus ing tank. The contents of the loading to onsite wastewater systems by as much as 50 percent. tank must be periodically pumped and transported to a light-weight aggregates have wastewater treatment plant. tion of media are added that achieved greater than 90 per- Many health departments react specifically to immobi- cent phosphorus removal in view holding tanks as a last- lize phosphorus. Typically, the test facilities. Filtralite® and resort option and because of media contain some combi- Utelite® are two brands of the cost of regular pumping nation of iron, aluminum, or manufactured clay aggregates this is an expensive option. calcium compounds and the that have been used for phos- With the use of a micro-flush reactions are similar to the phorus removal media. toilet the intervals between adsorption and precipitation pumping can be extended reactions that occur in soil. A wide variety of industrial by- helping to reduce costs. The goal is to enhance and products have been investi- maximize the reactions in a gated for use in reactive media Advanced Treatment more controlled environment. filters including different types of blast furnace or steel fur- Although advanced treat- The types of media used have ment systems for phos- been categorized as natural, phorus reduction in onsite 7 PIPELINE – Summer 2013; Vol. 24 No 1. National Environmental Services Center (800) 624-8301 or (304) 293-4191 Phosphorus and Onsite Wastewater Systems

Perforated Distribution Pipe nace slags and alkaline fly ash from coal-fired power plants. The composition of industrial slags varies depending on the type of industrial process that Soil Backfill generated the slag. A high rate of phosphorus removal Barrier Material has been documented using some slags. However, a draw- Gravel back with some slags is that they generate a high pH in the water exiting the filter, which means an extra treatment step may be needed to neutralize Phosphorous the pH before final dispersal. Removal Media Recently there has been much interest in the use of nano- Original Soil materials for phosphorus removal. As the overall surface area of a medium increases A number of media have been suggested for use in the number of attachment sites for phosphorus also drainfield trenches to capture phosphorus. The medium increases. Because of the is added between the bottom of the drainfield line and extremely small size of nano- the trench bottom. A suitable medium must have a high particles, the total surface area capacity to immobilize phosphorus and sufficient per- exposed is greatly increased, meability. Since it will eventually need to be replaced it potentially giving these mate- rials a much higher capac- should have as long a lifespan as possible. ity for phosphorus removal

than other media. Iron-based In soils that are determined to Research is also being con- nano-materials have been have an inadequate or mar- ducted on adding a layer of coated onto base media and ginal capacity, in addition to material with a high capacity have also been incorporated advanced treatment, modifica- for immobilizing phosphorus into resins that can be regen- tion of the drainfield may also to the drainfield. These mate- erated once their phosphorus be considered. rials would be added to the removal capacity has been drainfield trenches between reached. As with other media, One modification that has the drainlines and the original because the demand for been suggested for marginal soil. Numerous materials have phosphorus removal is fairly soils is timed, pressurized been considered including recent, research and knowl- dosing of septic tank efflu- replacing gravel used in drain- edge of the effectiveness and ent to equalize flow over the fields with limestone or tire economic practicality of dif- entire drainfield. This elimi- chips. The effectiveness of tire ferent media are continually nates the localized, saturated chips comes from exposure of developing. flow conditions that often the iron present in steel belts.

Drainfield Modifications occur after surge flows in Many of the media that have conventional gravity-flow been suggested for use in Because phosphorus related systems. Another suggestion reactive media filters such as problems from septic systems has been the use of shallow imported iron or aluminum- have been perceived as rare, dispersal options, especially rich soils, industrial slag, or proposed sites for septic sys- the use of drip distribution clay aggregates may also be tems are seldom evaluated for systems in which the effluent candidates for incorporation their capacity to immobilize is dispersed within the root into drainfield trenches. phosphorus. However, in the zone of plants, which can then future, especially in sensitive biologically take up phospho- The criteria for these types watersheds or in the vicinity of rus and incorporate it into of drainfield amendments an impaired water body, it is plant tissue. These are more include a sufficient capac- likely that soils may be evalu- effective if any resulting non- ity to immobilize phosphorus ated more frequently for their woody plants are occasionally and a texture that allows flow ability to capture phosphorus. harvested to prevent localized that is slow enough to provide phosphorus accumulation. adequate contact time but not so slow as to cause exces- 8

PIPELINE – Summer 2013; Vol. 24, No. 1 National Environmental Services Center (800) 624-8301 or (304) 293-4191 Phosphorus and Onsite Wastewater Systems

sive ponding. Because the of Harmful Algal Blooms.” Interferences.” Annual material will eventually need Oceanography, Vol. 18, No. Review of Energy and the to be replaced it is impor- 2. Rockville, MD. Accessed Environment. 25:53-88. tant that the material have a at: http://www.chnep. Accessed at: http://www. long lifespan so the need for wateratlas.usf.edu/upload/ vaclavsmil.com/wp-content/ replacement is infrequent. It is documents/Eutrophication- uploads/docs/smil-article- preferable if the spent material AndHABs.pdf 2000-aree2000-2.pdf can be reused for horticultural or agricultural purposes. Cost Lombardo, Pio. 2006. Phos- Robertson, W.D. et al. 1998. considerations are, as always, phorus Geochemistry in “Review of Phosphate Mobil- a factor as well. Septic Tanks, Soil Absorp- ity and Persistence in 10

tion Systems, and Ground- Septic System Plumes.” Because the need for better water. Lombardo Associates, Groundwater, Vol. 36, No. control of phosphorus from Inc., Newton, MA. Accessed 6. Accessed at: http:// onsite wastewater systems is at: http://www.lom- info.ngwa.org/gwol/ a slowly emerging issue, the bardoassociates.com/ pdf/982964321.PDF options for dealing with it are pdfs/060410-P-Geochemis- also continuing to develop. try-FINAL-LAI-Version.pdf As the need to better protect Rosemarin, Arno. 2011. “Peak water resources and rehabili- Phosphorus and the Eutro- tate nutrient-impaired water Lowe, Kathryn et al. 2009. phication of Surface Waters: bodies becomes more neces- Influent Characteris- A Symptom of Disconnected sary it is likely that additional tics of the Modern Waste Agricultural and Sanitation options for phosphorus con- Stream from Single Policies” in On the Water trol will also become available Sources. Water Environ- Front: Selections from the in the future. ment Research Foundation, 2010 World Water Week Alexandria, VA. Accessed in Stockholm, J. Lundqvist References at: http://www.ndwrcdp. (ed.). Stockholm Water Insti- org/documents/04-dec- tute. Accessed at: http:// 1/04dec01web.pdf www.worldwaterweek.org/ Cucarella, Victor and Gunno documents/Resources/ Renman. 2009. “Phospho- Best/2010/2011_OTWF_ rus Sorption Capacity of Smil, Vaclav. 2000. “Phos- Arno_Rosemarin.pdf Filter Materials Used for phorus in the Environment: On-site Wastewater Treat- Natural Flows and Human ment Determined in Batch Experiments—A Com- parative Study.” Journal of Environmental Quality, 38: 381-392. Accessed at: https://www.agronomy. org/publications/jeq/ abstracts/38/2/381

Etnier, Carl et al. 2005. Micro-Scale Evaluation of Phosphorus Management: Alternative Wastewater Sys- tems Evaluation. Project No. WU-HT_03-22. Prepared for the National Decentralized Water Resources Capac- ity Development Project, Washington University, St. Louis, MO by Stone Environ- mental, Inc., Montpelier, VT. Accessed at: http://www. ndwrcdp.org/research_proj- ect_WU-HT-03-22.asp

Glibert, Patricia, et al. 2005. “The Role of Eutrophication in the Global Proliferation 9 PIPELINE – Summer 2013; Vol. 24 No 1. National Environmental Services Center (800) 624-8301 or (304) 293-4191 National Environmental Services Center WVU Research Corporation West Virginia University P.O. Box 6893

Morgantown, WV 26505-6893

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