What is the primary way that nitrogen and phosphorus end up in bodies of water?

6.4.1.3.4 Eutrophication potential

Eutrophication is a leading cause of impairment for many coastal marine and freshwater ecosystems. It is characterized by excessive growth of algae and plant due to increased availability of one or more limiting growth factors, which are needed to conduct photosynbook. Eutrophication is characterized by phosphate equivalence (PO4-eq) in life cycle impact assessments. Eutrophication is often detrimental to plants and ecosystems and leads to the vulnerability of economic and social structures. The following equation illustrates the calculation of the EP score (Hacatoglu, 2014):

(6.14)YEP=XEP(T)XEP

where XEP represents the actual life cycle emissions of PO4 per capita per year. XEP(T) represents the target value, which is calculated using the following equation (Hacatoglu, 2014):

(6.15)XEP(T)=EPref×αEP

where EPref represents the global annual per capita of PO4 emissions and αEP represents the adjustment factor.

10.1.3 Innovation in Recovery of Nutrients from Industrial Wastewater

Eutrophication of surface water from industrial and municipal wastewater often results in the destruction of many natural water bodies around the world. Nutrients like nitrogen and phosphates encourage such eutrophication. Algal bloom makes water bodies unfit for human use. However, eutrophication can largely be overcome by cutting the entry of nutrients to water bodies through municipal and industrial discharge. A recently developed hybrid technology [4] has the potential to solve this problem. This new technology integrates chemical and biological treatments with membrane separation and effectively separates the nutrients from ammoniacal industrial wastewater. The nutrients are recovered as valuable struvite fertilizer for subsequent use in agriculture and planned plantation. This novel approach simultaneously turns waste into a valuable resource, protects surface bodies from hazardous waste contamination, makes the treated water reusable, and adds economy to the wastewater-treatment technology. The associated cost is low and the plant operation promises continuous improvement of the water environment. As this technology is operationally fast, efficient, and economically attractive it is a sustainable technology.

1 Introduction

Eutrophication in most water bodies is an important environmental problem. It is caused by increasing nutrient loading associated to urban, industrial and agricultural activities. Eutrophication is associated to accelerated growth of phytoplankton (algal blooms). The presence of certain species of cyanobacteria within the blooms is of special care, as they may produce hepato- and neurotoxins that can severely compromise human and animal health. To address nutrient point sources, such as urban and industrial, much effort has been devoted to the development of wastewater treatment processes and facilities (Gernaey et al., 2004; Karuppiah and Grossmann, 2008). However, nonpoint nutrient sources, such as those associated to agricultural activities, have not received much attention (Estrada et al., 2009). In particular, increased eutrophication can be a key feature associated to the large-scale production of biofuels from energy crops when compared to fossil fuels. The life cycle wide emissions of nutrients depend on the application and losses of fertilisers during the agricultural production of biofuel feedstocks. External restoration techniques for nonpoint sources include the construction of artificial wetlands nearby the water bodies to remove nutrients and, in this way, decrease nutrient loading. Within in-lake restoration strategies, biomanipulation is based on the trophic chain theory and it has been applied to control phytoplankton growth in lakes and reservoirs. The basic idea is to keep a high grazing pressure on the phytoplankton community by the herbivore zooplankton by performing zooplanktivorous fish removal (Sondegaard et al., 2007). Another in-lake restoration strategy is hypolimniom aeration, so as to precipitate phosphorous compounds to the sediment, not becoming available for phytoplankton production. Three dimensional eutrophication models have been proposed for large lakes with horizontal uneven distributions (Hu et al., 2006) and for costal systems (Moll and Radach, 2003). In this work, we formulate a three-dimensional eutrophication model, based on a previous one-dimensional model (Estrada et al.; 2010) for a reservoir that provides drinking water for two cities in Argentina. The model is based on first principles, with parameters that have been tuned with collected data from the specific reservoir under study (Estrada et al., 2009). It includes dynamic mass balances for three phytoplankton groups and main nutrients. The model is developed within a control vector parametrization dynamic optimization framework in which the water body has been spatially discretized in volume elements. Numerical results provide quantitative information for planning restoration strategies over a one year horizon, as well as its effect on algae growth and nutrient concentration.

d) Broad-scale eutrophication

Eutrophication (anthropogenic nutrient enrichment) is a common phenomenon in enclosed bays and estuaries due to a combination of agricultural run-off and human and agricultural wastes (Correggiari et al., 1992). It can also scale up to larger areas such as the northern Adriatic, parts of the Baltic and the southern North Sea and possibly the Irish Sea, resulting in eutrophic seas (Allen et al., 1998). On a large scale, atmospheric input of nitrogen can also be important.

Eutrophication causes several effects in the marine ecosystem. Higher concentration of nutrients will lead to an increase in the abundance of phytoplankton and consequently greater food resources for filter-feeders such as mussels. However, the likelihood of harmful algal blooms (e.g. red tides) will also increase causing anoxia and thus killing macroalgae and marine invertebrates (Southgate et al., 1984). Macroalgal growth, for example ephemeral green algae, will also be faster in eutrophic conditions, in many instances being able to outpace grazing activities. On LCS, eutrophic waters coupled with high levels of disturbance will create optimal conditions for proliferation of slippery green algae. Sediments, in turn, will tend to become muddy and compact, leading to substantial changes in the chemical gradients in the sediment (e.g., anoxia) which will, in turn, modify the infaunal composition (i.e., reduction of diversity, and proliferation of opportunistic species). Impacts of eutrophication will be worse on the landward side of LCS, where water movement is significantly reduced, particularly if the structures are connected to the shore by groynes.

6.24.1 Introduction

Eutrophication of water courses, lakes, and marine environments is a major issue in most parts of the world. Looking back 150 years, the urban situation in the emerging industrial part of the world led to the introduction of water-based systems for conveying and discharge of sewage. At first, the wastewater was disposed into nearby watercourses and lakes. As the populations grow, this was not a sustainable solution – the natural wetlands became overloaded as evident from the odors. This untenable situation led to the development of more active treatment systems such as shallow ponds and sand filters. In 1914, the activated sludge technique was introduced by Arden and Lockett, a technique that still probably is the most common technique for wastewater treatment (WWT) in the industrial part of the world. In the 1960s, eutrophication became evident due to the high amounts of plant nutrients discharged from sewage treatment plants. The first and maybe the simplest solution was to remove phosphorus by chemical precipitation. The European Commission and national authorities have gradually, over the latest couple of decades, sharpened the treatment demands, especially with regard to nitrogen, in order to avoid further eutrophication in the sea. Hence, WWT today probably is more focused on removing phosphorus and nitrogen than pathogens. It is still argued whether phosphorus or nitrogen is limiting for the eutrophication process, that is, should either one or both of these elements be eliminated.

Simply put, biological WWT can be defined as a natural process in which organisms assist in environmental cleanup simply through their own life-sustaining activities. By studying the organisms in natural ecosystems, the biologists have explored their function and capacity to degrade organic matter and transform nutrients. Such information has then been used by engineers to design effective WWT systems, that is, the biological processes have been concentrated into well-regulated units. In addition, knowledge of geochemistry, hydrology, etc., is an essential component of a successful system for treating polluted waters. Hence, globally, WWT probably is the most common biotechnological process.

Though the same biological processes are the basis for most WWT systems, there are probably innumerable technological solutions for achieving the goal. The numbers of techniques are as many as there are sanitary engineers. However, the techniques may be categorized as follows: (1) soil filters and wetlands – terrestrial ecosystems working as natural filters; natural water courses, lakes, and wetlands; soils receiving irrigated wastewater; constructed wetlands and ponds; soil or sand absorption systems; and trickling filters and (2) treatment plants – rotating biological contactors; fluidized beds; and activated sludge systems including sequencing batch reactors (SBRs). This array of techniques describes the systems on a scale from natural ecosystems at one end to high-technology solutions at the other end. In the choice of WWT system to be used, many factors such as influent water characteristics, desirable effluent water quality, costs for building and maintenance, and population density and dimensioning have to be considered.

This article gives a general background on the microbial cell and biological processes important in all WWT; focuses on the importance of understanding the interaction between hydraulic performance and microbial processes to achieve effective nitrogen removal; and outlines the function of two common systems: the constructed wetland, requiring in-depth knowledge on hydraulic properties, and the activated sludge process, relying on advanced control and optimization. Finally, the article gives some perspectives on the future development of biological WWT systems and their use.

The Death of Lake Erie: The Price of Progress?

The demise of Lake Erie in the 1960s was emblematic of the environmental challenge growing out of the industrial and petrochemical revolutions of the nineteenth and twentieth centuries in the West. Companies, municipalities, and people in general had seemingly perceived water to be completely elastic in its ability to absorb any amount and type of pollution. Any waste that needed to be disposed of was directly discharged into surface waters, such as rivers, lakes, and oceans.

Lake Erie provides numerous lessons. For those of us who were learning the new language of environmental science, Lake Erie gave us a new paradigm, one of optimism where even highly polluted waters could be saved. For the decades that followed the 1960s, water bodies began to recover from even extremely polluted conditions. Although the science of limnology (the study of freshwater systems) had been well established within the hydrologic and biological science communities, the problems in Lake Erie helped to propel it into a much wider application. For example, eutrophication of freshwaters, especially ponds and lakes, became better understood in the context of Lake Erie (see the discussion box, “Eutrophication”).

Eutrophication

Healthy water bodies contain sufficiently low amounts of contaminants and sufficiently high amounts of dissolved oxygen (DO) to support a balance of aquatic life. The DO concentrations in surface waters can be reduced by both natural and human factors. Evidence of a healthy water body is its trophic state. Every lake fits into a particular trophic state, according to its degree of eutrophication, and all lakes change their trophic status over time. All lakes, even the most pristine, are undergoing nutrient enrichment and filling. Lakes can be divided into three categories based on trophic state—oligotrophic, mesotrophic, and eutrophic. These categories reflect a lake’s nutrient and clarity levels.

Limnologists refer to healthy water bodies as oligotrophic systems; that is, they contain little plant nutrients and are often continuously cool and clear. Oligotrophic waters have very low production of organic matter by photosynthesis and can support diverse animal life and collect optimal amounts of nutrients, mainly phosphorous and nitrogen, from natural sources, such as decomposing plant matter. When a water body becomes enriched in dissolved nutrients, especially phosphorous and nitrogen, they stimulate the growth of aquatic plant life, which can lead to the depletion of dissolved oxygen (DO). This is known as eutrophication.

Oligotrophic lakes (see Figure 4.1) are generally clear, deep, and free of weeds or large algae blooms. Though aesthetically appealing, they are low in nutrients and do not support large fish populations. Nutrient concentrations, such as phosphorous and nitrogen, are limiting, and aquatic macrophytes (large plants) and algae are less abundant. Oligotrophic water bodies typically have accumulated little plant debris on the bottom over the years since aquatic macrophytes and algae are less abundant. They generally have water clarity greater than four meters (i.e., the distance one can see down into the water) since the amounts of free-floating algae are low, as well as the absence of presence of coloring agents in dissolved substances and low concentrations of suspended particles. Fish and wildlife populations generally will be small because food and habitat are often limited. Oligotrophic water bodies usually do not support abundant populations of sportfish such as large-mouth bass and bream, and it usually takes longer for individual fish to grow in size in oligotrophic waters. However, oligotrophic lakes often develop a food chain capable of sustaining a very desirable fishery of large game fish, but these conditions can deteriorate in a short amount of time due to fishing pressure increases.

A mesotrophic lake (see Figure 4.2) can support moderate populations of living organisms. These lakes have moderate concentrations of nutrients and moderate growth of plant life, such as algae and/or macrophytes, owing to the moderate concentrations of nutrients (especially N and P). There is evidence of slight sediment buildup and organic accumulations. Clarity is between 2 and 4 m, so a mesotrophic lake is usually “swimmable and fishable,” to use a phrase made famous by the Federal Water Pollution Control Act of 1972.

Eutrophic waterbodies (see Figure 4.3) may be dominated by algal growth or by larger plant growth. If algae-dominated, the water may have a green, cloudy appearance from the colonies of algae suspended or floating in the water. If plant-dominated, the submersed macrophytes will decrease the concentrations of the green pigment, chlorophyll, and use much of the nutrient concentrations, making for clearer water. Thus clarity as indicated by Secchi depth readings are higher than if the water body were an algae-dominated eutrophic system. This makes trophic state classification based on appearance very difficult.

Like almost everything in the environment, there is an optimal range between too little and too much nutrient loading. A minimal amount of nutrients is needed in any ecosystem, but when this amount is exceeded, as was the case for Lake Erie some decades ago, algal growth can become prolific. In the right balance, algae serve as food sources and are crucial to energy and mass balances in aquatic systems. Out of balance, however, the algae use up too much of the DO needed by fish and other aquatic organisms. The nutrients find their way into water bodies through numerous avenues, but the major categories are either point sources or nonpoint sources. As the name implies, point sources deliver nutrients and other pollutants to surface waters from a single point, such as a pipe, conduit, outfall structure, or ditch. Non-point pollutants are those that flow over broad expanses, such as runoff from agricultural practices, mining, roads, neighborhoods, and urbanized areas. Another nonpoint source of pollutants is the atmosphere. In fact, atmospheric deposition can be the largest source of many contaminants. The nutrients can take on many physical and chemical properties. For example, nitrogen can be in solid phase, such as in a commercial fertilizer, in liquid phase, such as when ammonia is dissolved in runoff water, or in gas phase, such as when ammonia or nitric acid is found in soil pores. The chemical forms can also be diverse, such as when conditions make for a reduced form, for example, ammonia, or in an oxidized form, such as nitrite or nitrate. Thus, the process of eutrophication includes elevated biological productivity resulting from increased input of nutrients or organic matter into aquatic systems. For lakes, which do not flow as rapidly as streams, such increased biological productivity usually leads to decreased lake volume because organic detritus accumulates. Natural eutrophication continues as aquatic systems fill in with organic matter. This is contrasted with cultural eutrophication, which is exacerbated by human activities and the consequent point and nonpoint pollution.

In retrospect, the death sentence to Lake Erie was premature. The assumptions of the time were that things could not change enough to return biodiversity to the lake ecosystem. Thankfully, these predictions were wrong. However, the Great Lakes are still vulnerable. In fact, some new problems have emerged, whereas others have been solved. To wit, the invasion of opportunistic species that are threatening the diversity of enormous regions; notably the appearance and proliferation of the zebra mussel (Dreissenia polymorpha) throughout much of the Great Lakes (see the discussion in Chapter 6).

6.3.10 Eutrophication

Eutrophication is the process by which a body of water becomes enriched in dissolved nutrients (as phosphates), stimulating the growth of aquatic plant life usually resulting in the depletion of dissolved oxygen.

Table 1.5 lists more specifics on the various categories and thresholds for the DfE assessment.

Table 1.5. DfE Master Criteria Cleaning Productsa [18]

CategoryThresholdsAcute mammalian toxicityRoute (units)Median lethal dose/concentrationOral, LD50 (mg/kg-bw) (by weight)2000Dermal, LD50 (mg/kg-bw)2000Inhalation, LC50 (vapor/gas) (mg/L)20Inhalation, LC50 (dust/mist/fumes) (mg/L)5R20: Harmful by inhalation
R21: Harmful in contact with skin
R22: Harmful if swallowed
R23: Toxic by inhalation
R24: Toxic in contact with skin
R25: Toxic if swallowed
R26: Very toxic by inhalation
R27: Very toxic in contact with skin
R28: Very toxic if swallowed
And all combination risk phrases containing one or more of the above (R20-R28)H300: Fatal if swallowed
H301: Toxic if swallowed
H302: Harmful if swallowed
H310: Fatal in contact with skin
H311: Toxic in contact with skin
H312: Harmful in contact with skin
H330: Fatal if inhaled
H331: Toxic if inhaled
H332: Harmful if inhaledCarcinogenicityNational Toxicology ProgramKnown to be human carcinogen reasonably anticipated to be human carcinogenEPA(2005/1999) Carcinogenic to humans, likely to be carcinogenic to humans, or suggestive evidence of carcinogenic potential -1
(1996) Known/likely
(1986) Group A—Human carcinogen, Group B—probable human carcinogen, or Group C—possible human carcinogen-1IARCGroup 1—Carcinogenic to humans
Group 2A—Probably carcinogenic to humans
Group 2BvPossibly carcinogenic to humans -1EU CMR ListCategory 1—Known to be carcinogenic to humans
Category 2—Should be regarded as if carcinogenic to humans
Category 3—Cause for concern for humans owing to possible carcinogenic effectsEU Risk PhrasesR45: May cause cancer
R49: May cause cancer by inhalation
R40: Limited evidence of a carcinogenic effect
And all combination risk phrases containing R45, R49, or R40EU CLPH350: May cause cancer
H350i: May cause cancer by inhalation
H351: Suspected of causing cancerNIOSH Occupational Carcinogen Listhttp://www.cdc.gov/niosh/topics/cancer/npotocca.htmlGHSCategory 1A—Known to have carcinogenic potential for humans
Category 1B—Presumed to have carcinogenic potential for humans
Category 2—Suspected human carcinogensGenetic ToxicityEU CMR ListCategory 1—Substances known to be mutagenic to man
Category 2—Substances which should be regarded as if they are mutagenic to man
Category 3—Substances which cause concern for man owing to possible mutagenic effectsEU Risk PhrasesR46: May cause heritable genetic damage
R68: Possible risk of irreversible effects
And all combination risk phrases containing R46 or R68.CLPH340: May cause genetic defects
H341: Suspected of causing genetic defectsGHSCategory 1A—Chemicals known to induce heritable mutations in germ cells of humans
Category 1B—Chemicals which should be regarded as if they induce heritable mutations in the germ cells of humans
Category 2—Chemicals which cause concern for humans owing to the possibility that they may induce heritable mutations in the germ cells of humansNeurotoxicityRoute (units)Median lethal dose/concentrationOral (mg/kg-bw/day)100Dermal (mg/kg-bw/day)200Inhalation (vapor/gas) (mg/L/6 h/day)1Inhalation (dust/mist) (mg/L/6 h/day)0.2Repeated dose toxicityRoute (units)Median lethal dose/concentrationOral (mg/kg-bw/day)100Dermal (mg/kg-bw/day)200Inhalation (vapor/gas) (mg/L/6 h/day)1Inhalation (dust/mist) (mg/L/6 h/day)0.2EU risk phrasesR48: Danger of serious damage to health by prolonged exposure (repeated exposure)
And all combination risk phrases containing R48CLPH372: Causes damage to organs
H373: May cause damage to organsReproductive and developmental toxicityOral (mg/kg-bw/day)250Dermal (mg/kg-bw/day)500Inhalation (vapor/gas) (mg/L/6 h/day)2.5Inhalation (dust/mist) (mg/L/6 h/day)0.5EU CMR List-3Category 1—Substances known to impair fertility in humans or known to cause developmental toxicity in humans
Category 2—Substances which should be regarded as if they impair fertility in humans or cause developmental toxicity to humans
Category 3—Cause concern for human fertility or possible developmental toxic effectsEU Risk Phrases-3R60: May impair fertility
R61: May cause harm to the unborn child
R62: Possible risk of impaired fertility
R63: Possible risk of harm to the unborn child
R64: May cause harm to breastfed babies
R33: Danger of cumulative effects
And all combination risk phrases containing R60-R64 or R33CLP-3H360: May damage fertility or the unborn child
H361: Suspected of damaging fertility or the unborn child
H362: May cause harm to breastfed childrenRespiratory sensitizationEU risk phraseR42: May cause sensitization by inhalationCLPH334: May cause allergy or asthma symptoms or breathing difficulties if inhaledGHSCategory 1A—High frequency of occurrence or sensitization rate in humans
Category 1B—Low-to-moderate frequency of occurrence or sensitization rate in humansSkin sensitizationEU risk phraseR43: May cause sensitization by skin contactCLPH317: May cause an allergic skin reactionGHSCategory 1A—High frequency of occurrence in humans and/or a high potency in animals
Category 1B—Low to moderate frequency of occurrence in humans and/or a low to moderate potency in animalsEnvironmental toxicity and fateIf a chemical is an acute aquatic toxicant (i.e., L/E/IC50 < 100 ppm), then it must biodegrade rapidly and not be bioaccumulative (see lines 1-3 below). If a chemical has low aquatic toxicity (see line 4 below), then its half-life must be less than 60 daysLineAcute aquatic toxicity value (L/E/IC50) 4,5,6Persistence (measured in terms of level of biodegradation)Bioaccumulation potential1If ≤ 1 ppm……then may be acceptable if the chemical meets the 10-day window as measured in a ready biodegradation test without degradation products of concern8……and BCF/BAF
< 10002If > 1 ppm and ≤ 10 ppm……then the chemical must meet the 10-day window as measured in a ready biodegradation test without degradation products of concern …83If > 10 ppm and < 100 ppm……then the chemical must reach the pass level within 28 days as measured in a ready biodegradation test without degradation products of concern8…4If ≥ 100 ppm……then the chemical need not reach the pass level within 28 days as measured in a ready biodegradation test if there are no degradation products of concern8 and its half-life < 60 days…EutrophicationThe total level of phosphorus in the cleaning product will be limited to a maximum level of 0.5 wt% in the cleaning product as sold (measured as elemental phosphorus). Inorganic phosphates, as defined by the EPA New Chemicals Program, cannot make up any portion of the 0.5 wt% of phosphorus1. Chemicals listed as “possibly carcinogenic to humans” are evaluated largely on animal studies. DfE will consider appropriate data that show cancer concerns are not relevant to humans, e.g., because of an animal-specific tissue effect or mode of action. If the data demonstrate that cancer concerns are not relevant to humans, that chemical can be considered under the DfE Criteria2. Per EU guidance, chemicals classified as Category 3 substances may be placed in that category based on positive results in assays showing (a) mutagenic effects or (b) other cellular interaction relevant to mutagenicity. If a chemical is classified in Category 3(b) only and that classification appears overly conservative, then the submitter may request EPA expert review. In such as case, if EPA determines the data do not support a concern for possible mutagenic effects, then the chemical will pass the criteria3. The EU classification criteria do not currently consider a limit dose above which an adverse effect would not trigger classification. EPA will consider evidence demonstrating that a chemical carrying a reproductive/developmental toxicity risk phrase or listed as toxic to reproduction (in Table 1.6) did not cause an adverse effect below the Toxic Substances Control Act (TSCA) 8(e) Guidance Values listed in Table 1.6. Such a chemical may be determined, upon EPA review, to pass the DfE criteria for reproductive/developmental toxicity4. In general, there is a predictable relationship between acute aquatic toxicity and chronic aquatic toxicity for organic chemicals, i.e., chemicals that have high acute aquatic toxicity may also have high chronic aquatic toxicity at low concentrations [20]. Since acute aquatic toxicity data are more readily available, the DfE Screens use these data to screen chemicals that may be toxic to aquatic life. Where measured chronic toxicity data is available, it will be assessed with other data and applied in the screen based on the relationship between acute and chronic aquatic toxicity5. A case-by-case approach focusing on rate of biodegradation and degradation products of concern will be implemented for chemicals toxic to aquatic organisms at ≤ 1 ppm6. For determining the aquatic toxicity of substances that are not toxic at their solubility limit, see ECOSAR Technical Reference Manual Figure 9, p. 17 (http://www.epa.gov/oppt/newchems/tools/ecosartechfinal.pdf); When a chemical may have effects at saturation as determined using the guidance in the ECOSAR manual, a weight-of-evidence approach in combination with US EPA expert review will be used. EPA may require additional testing including but not limited to solubility testing, chronic aquatic toxicity testing, or acute aquatic toxicity testing of analogs7. Degradation products of concern are compounds with high acute aquatic toxicity (L/E/IC50 ≤ 10ppm) which mineralize < 60% in 28 days

What is the primary way that nitrogen and phosphorus and up in bodies of water like the Chesapeake Bay?

What is the primary way that nitrogen and phosphorus end up in bodies of water like the Chesapeake Bay quizlet?

How does phosphorus and nitrogen enter water?

What is the main way in which excess phosphorus and nitrogen get into bodies of water to result in eutrophication?