Nutrient Recovery Technologies Research Articles

Identifying Amsterdam's nutrient hotspots: A new method to map human excreta at building and neighborhood scale

AbstractRecovering nutrients from human excreta and wastewater has been receiving increasing attention as a means to supplement or replace synthetic fertilizer production. Apart from technologies for nutrient recovery at centralized wastewater treatment plants, numerous decentralized, source‐separated sanitation systems, also known as new sanitation systems, have been developed to facilitate recovery. Decision‐making for the planning and implementation of new sanitation systems would benefit from a spatially explicit inventory of nutrient hotspots in urban areas. To provide visual representations of nutrient loads, we developed a methodology that combines spatial‐temporal modeling with geographic information system analysis, and used it for the city of Amsterdam. The methodology is new in the field of nutrient mapping, especially at the smallest geographical scale: building. Nitrogen, phosphorus, and potassium loads and hotspots are mapped at both building and neighborhood scale, drawing attention to the need for multiple scale analyses in decision‐making. This study concludes with a discussion on the potential to further develop the method proposed to include more detailed and verified data and to identify nutrient hotspots that are promising as nutrient recovery sites with new sanitation systems.

Logistics Network Management of Livestock Waste for Spatiotemporal Control of Nutrient Pollution in Water Bodies.

Nutrient pollution is a widespread water quality problem, which originates from excess nutrient runoff from agricultural land, improperly managed farming operations, and point sources such as wastewater treatment plants. Some nutrient pollution impacts include harmful algal blooms (HABs), hypoxia, and eutrophication. HABs are major environmental events that cause severe health threats and economic losses (e.g., tourism, real estate, commercial fishing). A dimension of the nutrient pollution problem that has not received much attention is that this interacts with organic waste management practices. As a result, it is important to connect the time and location of point and nonpoint nutrient source releases, nutrient soil content, spatial layout, and hydrology of agricultural lands with the transport of nutrients to water bodies and their impacts on aquatic ecosystems. In this work, we show how nutrient concentration in water bodies and other spatiotemporal factors are related to HAB development and how logistics management of livestock waste can be used to conduct space-time management of nutrient pollution. A case study for the Upper Yahara Watershed in the State of Wisconsin (U.S.) is employed to demonstrate the practicability of the modeling framework. Our framework reveals that logistics network management for waste and nutrients can reduce the incidence rates of HABs, but reducing it to nonharmful levels would require long-term efforts such as installing nutrient recovery technologies, coordinating manure storage and application, and deploying management incentive plans.

Optimal Recipe Assessment of Iron Filing-Based Green Environmental Media for Improving Nutrient Removal in Stormwater Runoff

Abstract Nutrient removal and recovery (NRR) technology was investigated using green sorption media with respect to 4 distinct clay and iron filing quantities in the media matrix. Column study test...

Innovative Processes and Technologies for Nutrient Recovery from Wastes: A Comprehensive Review

Waste management is necessary for environmental and economic sustainability, but it depends upon socioeconomic, political, and environmental factors. More countries are shifting toward recycling as compared to landfilling; thus, different researchers have presented the zero waste concept, considering the importance of sustainability. This review was conducted to provide information about different well established and new/emerging technologies which could be used to recover nutrients from wastes and bring zero waste concepts in practical life. Technologies can be broadly divided into the triangle of nutrient accumulation, extraction, and release. Physicochemical mechanisms, plants, and microorganisms (algae and prokaryotic) could be used to accumulate nutrients. Extraction of nutrient is possible through electrodialysis and crystallization while nutrient release can occur via thermochemical and biochemical treatments. Primary nutrients, i.e., nitrogen, phosphorus, and potassium, are used globally and are non-renewable. Augmented upsurges in prices of inorganic fertilizers and required discharge restrictions on nutrients have stimulated technological developments. Thus, well-proven technologies, such as biochar, composting, vermicomposting, composting with biochar, pyrolysis, and new emerging technologies (forward osmosis and electro-dialysis) have potential to recover nutrients from wastes. Therefore, reviewing the present and imminent potential of these technologies for adaptation of nutrient recycling from wastes is of great importance. Since waste management is a significant concern all over the globe and technologies, e.g., landfill, combustion, incineration, pyrolysis, and gasification, are available to manage generated wastes, they have adverse impacts on society and on the environment. Thus, climate-friendly technologies, such as composting, biodegradation, and anaerobic decomposition, with the generation of non-biodegradable wastes need to be adopted to ensure a sustainable future environment. Furthermore, environmental impacts of technology could be quantified by life cycle assessment (LCA). Therefore, LCA could be used to evaluate the performance of different environmentally-friendly technologies in waste management and in the designing of future policies. LCA, in combination with other approaches, may prove helpful in the development of strategies and policies for the selection of dynamic products and processes.

Sustainable Sewage Sludge Management: From Current Practices to Emerging Nutrient Recovery Technologies

Nutrient recovery from secondary resources, such as wastewater, has received increasing attention in recent years. Nutrient cycle sustainability and recycling approaches are important measures under development and considerations. This paper aims to present an overview of routes and technologies for nutrient recovery from sewage sludge and measures for improving their sustainability. First, current routes for nutrient recovery from sewage sludge are briefly reviewed. Next, an overview of commercial nutrient recovery technologies, projects, and emerging techniques around the world with the key factors for a successful phosphorus recovery technology is presented. Finally, a proposal for improving the sustainability of these practices is presented. It is concluded that the gap between demand and supply can be a major driver for the shift from ‘removal and treat’ to ‘recovery and reuse’. Moreover, there is not, and will never be, a one-size-fits-all solution. Future strategies and roadmaps need to be adapted to the local economy and geographical context more than ever.

Transport of pharmaceuticals during electrodialysis treatment of wastewater

Electrodialysis (ED) is a promising emerging electrochemical membrane technology for nutrient concentration and recovery from wastewater. However associated environmental safety aspects have to be assessed before utilizing concentrated nutrient produced by ED, for instance as fertilizer. Municipal wastewaters contain various micropollutants that have the potential of being concentrated during the ED treatment processes. This study quantified the transport of pharmaceuticals during ED nutrient recovery from synthetic centrate wastewater. Specifically, it is evaluated whether pharmaceutical micropollutants are mobile, and therefore able to transport across the cation exchange membranes and concentrate into the ED concentrate product. Results demonstrate that NH4+-N, PO43--P and K+ could be concentrated up to 5 times in the concentrated ED product (3700–4000 mg/L NH4+-N, 21–25 mg/L PO43--P, 990–1040 mg/L K+). Target micropollutants, such as diclofenac, carbamazepine and furosemide were largely retained in the diluent, with less than 8% being transported across to the concentrate product (feed micropollutant concentration 10 or 100 μg/L) based on the final target pharmaceutical amounts in the ED concentrate product (μg). Some transport of micropollutants such as atenolol, metoprolol and hydrochlorothiazide was observed to the concentrate product. For instance a final concentration of 10.3, 9.4 and 8.6 μg/L on average was measured for these pollutants in the final ED concentrate product (final volume ∼1 L) in experiments with a feed water (initial volume 20 L) containing only 10 μg/L of target pharmaceuticals. Transport of pharmaceuticals across the ED membranes was concluded to be dominated mainly by the molecule hydrophobicity/hydrophilicity as well as electrostatic interactions between pharmaceutical molecules and ED membranes. Particularly excluded were those having a negative charge and high hydrophobicity such as diclofenac and ibuprofen.

Fractionating various nutrient ions for resource recovery from swine wastewater using simultaneous anionic and cationic selective-electrodialysis

Different from current nutrient recovery technologies of recovering one or two nutrient components (PO43− or NH4+) from wastewater, this study aimed to fractionate various nutrient anions and cations simultaneously, including PO43−, SO42−, NH4+, K+, Mg2+ and Ca2+, into several streams. The recovered streams could be further paired together to produce high-value products. A novel electrodialysis process was developed by integrating monovalent selective anion and cation exchange membranes into an electrodialysis stack. Results revealed that nutrient recovery was achieved effectively by fractionating PO43− and SO42− into the anionic product stream, whereas bivalent cations (Mg2+ and Ca2+) were extracted in the cationic product stream and the monovalent cations (K+ and NH4+) were concentrated in the brine stream. For the permeation capabilities of anions, SO42− and Cl− possessed the higher preference, whereas PO43− permeated the membrane more difficult. As to the cations, the permeation sequence was: NH4+≈K+ >Ca2+>Mg2+≈Na+. Enhancing voltage values not only promoted ion migration rates, but also led to the increase of energy consumption. Although elevating initial phosphate concentration in the anionic product streams from 60 mg/L to 470 mg/L did not influence phosphate fractionation significantly, the current efficiency decreased from 3.55% to 0.65% and a remarkable increased of energy consumption from 29.42 kWh/kg NaH2PO4 to 160.13 kWh/kg NaH2PO4 was observed. Further experiments were conducted for phosphorus recovery by pairing two recovered product streams, which revealed that phosphate precipitation could be achieved by using inherent Ca2+ and Mg2+ in the wastewater without dosing external cation sources.

Customizing anaerobic digestion-coupled processes for energy-positive and sustainable treatment of municipal wastewater

Anaerobic digestion (AD) technologies offer exciting opportunities for implementation of sustainable wastewater management, which are currently still an energy-intensive and costly process. However, selecting an appropriate AD process is challenging because the treatment performances vary significantly with the technology type, wastewater properties and environmental conditions and a trade-off between the treatment efficiency and other cost and environmental impacts is usually applied. In this study, a multi-criteria evaluation method which gives a balanced consideration between multiple sustainability dimensions and the practical implementation conditions for a specific treatment process was developed for AD-coupled processes evaluation. Six indicators across three metrics (i.e., environmental, economic, and technical performances) were covered in the method. Two representative AD-coupled processes for municipal wastewater treatment and four countries (United States, United Kingdom, China, and India) were selected for the evaluation. A national-specific evaluation shows that the high-rate activated sludge + sludge anaerobic digestion always outperforms the other processes (presently and in the near future) except for India, where up-flow anaerobic sludge blanket + activated sludge process stands out as the currently optimal option based on the 2015 data. Moreover, it is suggested that implementing AD-coupled nutrient recovery technologies will be economically more feasible for the developed countries than the developing ones, because the latter will still prioritize the economically- and environmentally-beneficial technologies in the near future. This work may help identifying key area of improvement needed for municipal wastewater sectors in different countries and provide guidance for national and global policy-makers to promote customized implementation of AD-coupled processes towards energy-positive and sustainable wastewater treatment.

Vermicomposting by Eisenia fetida is a Sustainable and Eco-Friendly Technology for Better Nutrient Recovery and Organic Waste Management in Upland Areas of China

Management and recycling of organic waste materials such as agricultural crops (wheat straw, rapeseed) and animal manure (pig manure, cow dung) is becoming an important issue in rapidly growing population. Vermicomposting by earthworms (Eisenia fetida) is useful technique to recover nutrients of plants such as NPK (nitrogen, phosphorus, calcium). A vermicomposting system using the earthworm species (Eisenia fetida) and treating it with cattle dung, pig manure and biochar with crop (wheat straw and rapeseed) waste was established in upland areas of China. It was monitored for two months. Four treatments (T1 to T4) were prepared using crop residues i.e. wheat straw, rapeseed and cow manure in different concentrations. Vermicomposting through biochar (Biochar 50%, rapeseed residues 20% and Biochar with earthworms) gave maximum increase in soil fertility with maximum decrease (39.63%) in C:N ratio. Significant increase of N content in nutrients and reduction in C: N ratios during this process shows conversion of harmful wastes into useful fertilizer.

Production and performance of bio-based mineral fertilizers from agricultural waste using ammonia (stripping-)scrubbing technology

Development and optimization of nutrient recovery technologies for agricultural waste is on the rise. The full scale adoption of these technologies is however hindered by complex legal aspects that result from lack of science-based knowledge on characterization and fertilizer performance of recovered end-products. Ammonium sulfate (AS) and ammonium nitrate (AN), end-products of (stripping-)scrubbing technology, are currently listed by the European Commission as high priority products with the potential of replacing synthetic N fertilizers. The legal acceptance of AS and AN will be highly dependent on critical mass of scientific evidence.This study describes four different (stripping-)scrubbing pathways to recover ammonia with an aim to (i) assess product characteristics of ammonium nitrate (AN) and ammonium sulfate (AS) produced from different installations, (ii) evaluate fertilizer performance of recovered end-products in greenhouse (Lactuca sativa L.) and full field (Zea mays L.) scale settings and (iii) compare the observed performances with other published studies. Results have indicated that the recovered products might have a different legal status, as either mineral N fertilizer or yet as animal manure, depending on the used (stripping-)scrubbing process pathway. Nevertheless, no significant differences in respect to product characterization and fertilizer performance of AN and AS have been identified in this study as compared to the conventional use of synthetic N fertilizers. This indicates that recovered AS and AN are valuable N sources and therefore might be used as N fertilizers in crop cultivation.

The role of source separation in nutrient recovery – Comparison of alternative wastewater treatment systems

The availability of mineral fertilizers is becoming more challenging in the future. In source separated human urine, nutrient ratio is suitable for fertilizer use and nutrients are readily available for plants. In this study the aim was to acquire scientific data of the environmental impacts and nutrient potentials of wastewater separating systems, i.e. urine and blackwater source separation. At the same time, general acceptance on the use of human urine in agriculture wanted to be improved. In addition, the value of urine as a fertilizer was calculated. The focus of the study was on rural areas but comparison between different systems included also the nutrient potential of urban areas as well. Based on the results, human urine was found to be an environment friendly fertilizer. Applying source-separation systems in rural areas, four times more phosphorus and over thirty times more nitrogen could be recovered compared to the current wastewater treatment system. Furthermore, eutrophication impact is reduced to one fifth. However there is a risk of increased soil acidification but it can be minimized with advanced spreading techniques, like deep injection. The results of this study support the use of source-separation technologies for nutrient recovery.

CURRENT UNDERSTANDING ON INDUSTRIAL ORGANIC WASTE MANAGEMENT BY EMPLOYING Eisenia fetida

Earthworms have the inherent capability of stabilising different organic waste materials of industrial as well as domestic origin. This review paper depicts the potential of epigeic earthworm species Eisenia fetida in the vermistabilisation of various industrial organic wastes such as silk industry waste, herbal pharmaceutical industry sludge, food industry sludge, milk processing industry sludge, tea factory coal ash, sugar mill sludge, cotton industrial waste, paper mill waste, and bio sludge of beverage industry. The analysis of results obtained clearly indicates the suitability of vermicomposting over conventional composting as an alternative technology for management, stabilisation and nutrient recovery from industrial organic waste.

Adsorption of nutrients using low-cost adsorbents from agricultural waste and by-products – review

Nutrient removal has become one of the key challenges for wastewater treatment facilities all over the world due to the harmful effect of these pollutants on water bodies and ecosystems known by eutrophication, however, most of the currently used technologies are not focused on nutrients recovery from wastewater. Recently, using agricultural waste/by-products for adsorption of nutrients acquired more interest because of their abundant availability, low-cost, high efficiency and eco-friendly advantages and this method may become more environmentally sustainable through maximizing removal while delivering nutrient and energy recovery technologies with economically attractive return on investment. This review investigates the application of agricultural waste/by-products as bio-sorbent for phosphate, ammonium and nitrate removal with a focus on the modification methods and the process mechanism including influent parameters, kinetics and isotherms.

Technologies and logistics for phosphorus recovery from livestock waste

Phosphorus (P) runoff from livestock waste can trigger algal blooms that adversely affect aquatic life and human health. One strategy to mitigate this problem is to install nutrient recovery technologies that concentrate and mobilize nutrients from nutrient-rich regions to nutrient-deficient ones. We present supply chain design formulations to identify optimal types and locations for P recovery technologies. The formulations capture trade-offs in transportation costs, technology efficiency, investment/operational costs, revenue collected from different recovered products (struvite and nutrient cakes), and environmental impact. Our computational framework is used to analyze the impact of different scenarios for market prices of recovered products, recovery yields, and remediation costs. We find that transportation of waste alone (without any processing) can achieve significant reductions in environmental impact at low cost, but cannot achieve economic sustainability in the long run due to the lack of direct revenue streams. Mechanical separation technologies that recover P in the form of nutrient cakes are low-cost solutions that can achieve high environmental benefits and reduced transportation costs, but revenues are also limited due to low values of the cakes. Struvite crystallization in fluidized beds is found to be a highly attractive option under current struvite prices, but economic sustainability is strongly dependent on yield recoveries (which are currently highly uncertain).

Energy-neutral sustainable nutrient recovery incorporated with the wastewater purification process in an enlarged microbial nutrient recovery cell

Recovery of nutrient resources from the wastewater is now an inevitable strategy to maintain the supply of both nutrient and water for our huge population. While the intensive energy consumption in conventional nutrient recovery technologies still remained as the bottleneck towards the sustainable nutrient recycle. This study proposed an enlarged microbial nutrient recovery cell (EMNRC) which was powered by the energy contained in wastewater and achieved multi-cycle nutrient recovery incorporated with in situ wastewater treatment. With the optimal recovery solution of 3 g/L NaCl and the optimal volume ratio of wastewater to recovery solution of 10:1, >89% of phosphorus and >62% of ammonium nitrogen were recovered into struvite. An extremely low water input ratio of <1% was required to obtain the recovered fertilizer and the purified water. It was proved the EMNRC system was a promising technology which could utilize the chemical energy contained in wastewater itself and energy-neutrally recover nutrient during the continuous wastewater purification process.

Electroactive haloalkaliphiles exhibit exceptional tolerance to free ammonia.

Electrochemical activity in bacteria has been observed in numerous environments and conditions. However, enrichments in circumneutral freshwater media where acetate is the main electron donor seem to invariably lead to the dominance of Geobacter spp. Here we report on an electroactive bacterial consortium which was enriched on acetate as electron donor, but in a medium which reproduces hydrolysed urine (high pH, high salinity and high free ammonia). The consortium was found to be free of Geobacter species, whereas a previously undescribed community dominated by species closely related to Pseudomonas and Desulfuromonas was established. The salient features of this community were as follows: (i) high electroactivity, with anodic current densities up to 47.4 ± 2.0 A m-2; (ii) haloalkaliphilicity, with top performance at a medium pH of 10 and 19.5 ± 0.5 mS cm-1; and (iii) a remarkably high tolerance to free ammonia toxicity at over 2200 mgNH3-N L-1. This community is likely to find applications in microbial electrochemical technology for nutrient recovery from source-separated urine.

Ecological Sanitation and nutrient recovery from human urine: How far have we come? A review

Abstract To address the shortcomings of modern wastewater treatment, Ecological Sanitation (EcoSan) has been advocated as a sustainable approach to promote closed-loop flows of resources and nutrients from sanitation to agriculture. In this study, we discuss the rationale behind its conception and provide a state-of-the-art review on the subject. Through an exhaustive literature analysis of EcoSan systems, its historical developments and programs implemented worldwide we (i) validate the potential applicability and feasibility of decentralized, source-based sanitation and (ii) depict fundamental problems in EcoSan systems design that have stalled its adoption and proliferation. Specifically, we focus on urine diversion to demonstrate its potential to elegantly separate, collect and concentrate products that we require (nutrients) and those that we wish to regulate (pathogens and micropollutants). Since recent research efforts have been devoted to the technological recovery of nutrients from human urine, we believe that we are witnessing a paradigm shift within a paradigm shift as it represents a change in emphasis from ‘split-stream collection and reuse’ to ‘split-stream collection, resource recovery and safe reuse’. Our analysis of various nutrient recovery technologies for human urine indicates that provisioning of urine-diverting toilets tends to reduce sanitary risks; however, to contain and completely eliminate these risks continued research effort is needed to envision and implement integrated technological pathways that ensure simultaneous nutrient recovery, pathogen inactivation and reduction of pharmaceuticals and active substances.

Nutrient Recovery from Digestate: Systematic Technology Review and Product Classification

Nutrient recovery from digested biodegradable waste as marketable products has become an important task for anaerobic digestion plants to meet both regulatory drivers and market demands, while producing an internal revenue source. As such, the present waste problem could be turned into an economic opportunity. The aim of this study was to provide a comprehensive overview and critical comparison of the available/emerging technologies for nutrient recovery from digestate, and a classification of the resulting end-products according to their fertilizer characteristics. Based on the stage of implementation, the technical performance, as well as financial aspects, struvite precipitation/crystallization, ammonia stripping and (subsequent) absorption using an acidic air scrubber were selected as best available technologies to be applied at full-scale for nutrient recovery as marketable fertilizer commodities. The resulting end-products can and should be classified as renewable nitrogen–phosphorus (N/P) precipitates and nitrogen–sulfur (N/S) solutions, respectively, in fertilizer and environmental legislations. This would stimulate their use and foster nutrient recovery technology implementation.

Englés

Anaerobic digestion is a worldwide technology to treat organic waste streams, primarily due to its capacity to produce methane as renewable energy. However, there is an increasing interest on nutrient recovery (N and P), which from both environmental and economic reasons have been identified as key feature in anaerobic digestion plants. The manuscript presents a comprehensive overview on recent advances in nutrient recovery technologies applicable for anaerobic digestion systems. The review focus on N and P recovery through the use of digestates as fertilizers, struvite precipitation and biological systems such as phycoremediation (i.e. algae cultivation) and polyphosphates accumulating organisms. Keywords: Anaerobic digestion, nutrient recovery, struvite, phycoremediation, fertilizer.

Liquid fertilizer products from anaerobic digestion of food waste: mass, nutrient and energy balance of four digestate liquid treatment systems

This study compared four different digestate liquid treatment systems of a theoretical anaerobic digestion plant in order to facilitate the utilization of municipal food waste nutrients in agriculture. The mass, nutrient and energy balances of a theoretical plant digesting 60 kt/y of food waste were used to evaluate the feasibility of the treatments to concentrate nutrients into liquid fertilizer products. The studied technologies for digestate liquid treatment were ammonia stripping, ammonia stripping combined with reverse osmosis (RO), evaporation combined with RO, and stripping combined with both evaporation and RO. As a result, processing of digestate into concentrated fertilizer products consumed less than 10% of the produced energy from food wastes and was also sufficient for the heat-demanding digestate liquid treatments, evaporation and stripping. The digestate liquid treatment systems were considered as nitrogen and potassium concentration methods which were able to concentrate up to 67% of the feedstock nitrogen into transportable fertilizer products with low mass. Of the studied digestate systems evaporation combined with RO was evaluated as the most efficient nutrient recovery technology for the production of transportable fertilizer products due to the high concentration of nutrients and nutrient availability as well as low product mass and energy consumption. Overall, the selection of the treatment technology is dependent on the location of the anaerobic digestion plant relative to the agricultural land and the type of fertilizer products needed.