Sewage Waste Research Articles

MULTIVARIATE APPROACHES TO CLUB LARGE WATER QUALITY DATA FROM AQUATIC TOXICITY STUDIES: A REVIEW STUDY

Water is the most valuable, widespread resource, major constituent of all living creatures and extremely essential for the sustenance & existence of life. This is exemplified by its multiple uses such as drinking, cooking, washing, irrigation, farming, industrial activities and many more. Quality of surface waters are getting deteriorated as water resources are polluted due to the discharge of industrial effluents, agricultural run-off having insecticides, pesticides, heavy metals, fertilizers, chemicals, sewage and other domestic wastes. This review strongly recommends the incorporation of regular monitoring programmes for reliable estimation of water quality, effective pollution control and water resource management. The practice of conducting physicochemical studies is even essential/mandatory before conducting any toxicity study using fishes or any other sentinel organism both for in-vivo and in-vitro studies. Frequent sampling at many sites with a lot of water quality parameters generates a large & complex data matrix that needs data interpretation. The use of different multivariate approaches provide a rapid solution by identifications of factors that are mainly influencing water quality, clustering many parameters to identify the parameters mainly responsible for spatial and temporal variations linked to seasonality. In this way, reliable management of water resources as well as rapid solutions to pollution problems and effective environmental impact assessment can be approached.

Reregistration of the population residing in Foz do Iguaçu, Brazil, in compliance with the Primary Health Care PolicyReinscripción de la población residente en Foz do Iguaçu, Brasil, en cumplimiento de la Política de atención primaria de salud

To present the experience and results of the reregistration of residents in Foz do Iguaçu, a border town located in the state of Paraná, Brazil, to meet the guidelines of the national Primary Health Care (PHC) Policy and its new financing model (Programa Previne Brasil). A scanning strategy (convenience sample) was used for data collection, with 52 263 households visited and 22 710 interviews conducted from September to November 2019. The interviews were conducted face-to-face by 54 community health workers. Data were collected on the household (ownership status, urban or rural location, type of household, construction material, availability of electrical and sewage networks, water supply and waste disposal). Demographic and health information on the residents was also collected. The reregistration process revealed that most residents were home owners and lived in well-constructed homes, located mostly in urban areas, served by electricity, with access to water supply and garbage collection. Of the reregistered population, 52.8% were women, 62.5% were aged between 15 and 59 years and 60.0% declared themselves white. Among respondents aged 15 or over, 90.0% had completed elementary school. The main occupation was "formal salaried job". Additionally, 18.6% of the interviewees declared themselves to be hypertensive and 7.0%, diabetic. The reregistration process uncovered relevant information to support both PHC planning as well as social assistance, work and housing initiatives; it was also fundamental to define health care strategies in this border town during the COVID-19 pandemic.

Reapplication of biochar, sewage waste water, and NPK fertilizers affects soil fertility, aggregate stability, and carbon and nitrogen in dry-stable aggregates of semi-arid soil

Biochar has been applied to increased soil nutrients, especially C. In RCBD, control fresh water (CFW), sewage wastewater (SWW), NPK fertilizer, rice husk biochar (RHB), and NPK + RHB treatments were arranged with four replications. Soil chemical properties, dry-stable aggregate fractions [4.75–2.00 (Lma), 1.00–2.00 (Mma), 0.25–1.00 (Sma), and < 0.25 mm (Mia)], and aggregate total carbon (TC) and total nitrogen (TN) concentrations were evaluated over a 4-year period with repeated treatment additions in a vegetable-based rotation system. Soils amended with RHB, NPK and NPK + RHB showed slight acidification but no significant change in exchangeable cation content. The concentration of TC increased with NPK + RHB, NPK and RHB, while TN and available P increased with NPK and NPK + RHB treatments. The SWW increased soil pH and Na+ but decreased K+ concentration. Reapplication of SWW and NPK + RHB resulted in an increase in Lma formation by 28 % and 29 %, and MWD by 19 % and 21 %, respectively. The NPK and NPK + RHB treatments increased TC and TN in all aggregate fractions, while RHB only increased TC in macro-aggregates (4.75–0.25 mm) and TN in Sma. The increase in aggregate TC concentration was approximately 1.50–2.00 folds greater with NPK + RHB than with NPK and RHB treatments. Although the TC concentration was highest in both Mma and Sma fractions with the NPK + RHB treatment, the greater association of Lma (44 %) and Mma (31 %) with soil TC content may significantly affect the soil sustainability. The TC in Mma fraction was reflected in MWD (r = 0.53*, P = 0.05). Reapplication of RHB had limited potential for C and N sequestration in soil aggregates, but its combination with NPK produced a superior response in soil nutrients retention, soil structural stability, and TC and TN sequestration potential in micro- and macro- aggregate fractions. Therefore, NPK + RHB treatment is best suited for the sustainable management of the study and similar soils.

Hydrological regulation of nitrate sources, transformation and transport pathway in a karstic river

A comprehensive understanding of nitrate dynamics in rivers is vital for nitrogen management, especially for the karst zone with high leaching of nitrate producing potential risk to environmental quality. However, identification of the source-transformation-pathway of nitrate is limited in the karst rivers. Thus, a suit of hydrogeochemical parameters, including δ15N-NO3−, δ18O-NO3−, δ13C-DIC, δ18O-H2O, soil-related parameters (DOC) and geogenic ions (Mg2+, DIC), were used to identify nitrate sources and dynamics in the Wujiang River, a typical karstic river as a tributary of Changjiang River. The combined use of a conceptual model of normalized NO3− and DOC, and other hydrogeochemical parameters (δ13C-DIC, Mg2+, DIC) suggested that most nitrates were transported through the soil/epikarst pathway in the wet season, whereas >70 % of nitrates were transported through groundwater pathway in the dry season for Wujiang River. Nitrification and mixing were the dominant processes, meanwhile ∼31 % of nitrate was denitrified in the wet season in this study. The reanalysis of δ15N-NO3− and δ18O-NO3− values for reported karstic rivers in China and worldwide also revealed the predominant nitrification and denitrification in karst regions. The Bayesian model indicated that chemical fertilizer (CF, 42 %) and soil organic nitrogen (SON, 32 %) contributed the most in the wet season, while ∼60 % of nitrate originated from SON (31 %) and manure and sewage wastes (M&S, 30 %) in the dry season in the Wujiang River. The sustained contribution of non-point sources from nitrification through the soil/epikarst pathway might be related to the widespread porosities in the karst rivers. Thus, measures to reduce nitrogen leaching and improve fertilizer use efficiency should be considered, like water and soil conservation, slow-release fertilizer and nitrification inhibitors. Additionally, a suit of hydrogeochemical indicators proves to be helpful for identification of source, transformation and transport pathway of nitrate in the karst basin.

Genetic Determinants of Escherichia coli Survival in Beach Sand.

Escherichia coli contain a high level of genetic diversity and are generally associated with the guts of warm-blooded animals but have also been isolated from secondary habitats outside hosts. We used E. coli isolates from previous in situ microcosm experiments conducted under actual beach conditions and performed population-level genomic analysis to identify accessory genes associated with survival within the beach sand environment. E. coli strains capable of surviving had been selected for by seeding isolates originating from sand, sewage, and gull waste (n = 528; 176 from each source) into sand, which was sealed in microcosm chambers and buried for 45 days in the backshore beach of Lake Michigan. In the current work, survival-associated genes were identified by comparing the pangenome of viable E. coli populations at the end of the microcosm experiment with the original isolate collection and identifying loci enriched in the out put samples. We found that environmental survival was associated with a wide variety of genetic factors, with the majority corresponding to metabolism enzymes and transport proteins. Of the 414 unique functions identified, most were present across E. coli phylogroups, except B2 which is often associated with human pathogens. Gene modules that were enriched in surviving populations included a betaine biosynthesis pathway, which produces an osmoprotectant, and the GABA (gamma-aminobutyrate) biosynthesis pathway, which aids in pH homeostasis and nutrient use versatility. Overall, these results demonstrate that the genetic flexibility within this species allows for survival in the environment for extended periods. IMPORTANCE Escherichia coli is commonly used as an indicator of recent fecal pollution in recreational water despite its known ability to survive in secondary environments, such as beach sand. These long-term survivors from sand reservoirs can be introduced into the water column through wave action or runoff during precipitation events, thereby impacting the perception of local water quality. Current beach monitoring methods cannot differentiate long-term environmental survivors from E. coli derived from recent fecal input, resulting in inaccurate monitoring results and unnecessary beach closures. This work identified the genetic factors that are associated with long-term survivors, providing insight into the mechanistic basis for E. coli accumulation in beach sand. A greater understanding of the intrinsic ability of E. coli to survive long-term and conditions that promote such survival will provide evidence of the limitations of beach water quality assessments using this indicator.

Preference for rural living environment improvement initiatives in China

AbstractThe Chinese government has launched the Rural Living Environment Improvement Initiative (RLEII) to solve the poor living conditions in rural areas. The initiative enhances rural greenery; provides sanitary toilets; and promotes proper disposal of animal manure, sewage, and household waste in rural areas. We collected data using in‐person interviews with 938 rural residents in Xinjiang, China, to elicit their preference, preference intensity, and preference heterogeneity for RLEII. Results indicated that rural residents prefer to see shortcomings of the RLEII addressed. Rural greening construction is identified with the highest preference intensity. We also find significant heterogeneity in rural residents' preferences for each attribute of RLEII. The preference heterogeneity is rooted in the region's economic condition (poor vs. nonpoor region). It is essential to understand rural residents' choice for rural public goods supply and to respect their preference intensity, sequence, and heterogeneity for RLEII to enhance the implementation performance. We discuss the implications of these findings.

Dendrimer modified composite magnetic nano-flocculant for efficient removal of graphene oxide

Graphene oxide (GO) as an emergingnanomaterial has been widely used in water purification. However, practical removal of GO from water environment and industrial waste liquid remains a critical challenge.Here, a poly (amideamine)dendrimer (PAMAM) modified composite magnetic nano-flocculant (Fe3O4@SiO2@PAMAM) was fabricated and a new strategy for removal of GO was proposed combining the advantages of flocculation with magnetic separation. Results showed that high removal efficiency of more than 82.41 % could be attained under the conditions of an initial GO concentration of 100 mg/L, flocculation time of 60 s, Fe3O4@SiO2@PAMAM dose of 100 mg/L, and pH of 6.0. The maximum removal capacity of Fe3O4@SiO2@PAMAM for GO was approximately 238.10 mg g−1. Based on the charge neutralization and sweep flocculation, the prepared Fe3O4@SiO2@PAMAM demonstrated excellent application performance for removing GO in surface water, domestic sewage, and industrial waste liquid. A new magnetic nano-flocculant and an alternative technology strategy for treatment of GO was presented.

Watershed-Scale Shallow Groundwater Anthropogenic Nitrate Source, Loading, and Contamination Assessment in a Typical Wheat Production Region: Case Study in Yiluo River Watershed, Middle of China

Nitrate pollution in groundwater has become a global concern for agriculture and regional ecology. However, tracing the spatiotemporal groundwater nitrate pollution sources, calculating the total nitrogen loading, and assessing contamination at the watershed scale have not been well documented. In this study, 20 groundwater samplings from 2020 to 2021 (in dry and wet seasons) on the Yiluo River watershed in middle China were collected. Tracing groundwater nitrate pollution sources, calculating total nitrogen loading, and assessing contamination using dual isotopes (18ONO3 and 15NNO3), conservation of mass, and the nitrate pollution index (NPI), respectively. The results indicated that there were three nitrate sources in groundwater: (1) manure and sewage waste input (MSWI), (2) sediment nitrogen input (SNI), and (3) agriculture chemical fertilizer input (ACFI) in the Yiluo River watershed. ACFI and SNI were the main groundwater nitrogen pollution sources. The average nitrogen loading percentages of ACFI, SNI, and MSWI in the whole watershed were 94.7%, 4.34%, and 0.96%, respectively. The total nitrogen loading in the Yiluo River watershed was 7,256,835.99 kg/year, 4,084,870.09 kg/year in downstream areas, 2,121,938.93 kg/year in midstream areas, and 1,050,026.95 kg/year in upstream areas. Sixty percent of groundwater in the Yiluo River watershed has been polluted by nitrate. Nitrate pollution in midstream areas is more severe. Nitrite pollution was more serious in the wet season than in the dry season. The results of this study can provide useful information for watershed-scale groundwater nitrogen pollution control and treatment.

Coal and sewage waste process explored

Coal and sewage waste process explored

Diversity and ecology of freshwater diatoms as pollution indicators from the freshwater Ponds of Kanyakumari district, Tamilnadu

The present study explores the diversity and ecology of freshwater diatom in the Kanyakumari district, Tamilnadu. Six freshwater ponds namely, Thuckalay pond, Eraniel pond, Pampanvilai pond, Villukuri pond, Erachakulam and Thottiyodu pond were selected from Kalkulam Taluk in Kanyakumari district. A total of 27 taxa of 17 genera were recorded from these freshwater ponds. Among the freshwater diatom species, Gomphonema montanum was found to be the predominant species in all stations except St- 2. The correlation analysis between diatom density and physico-chemical parameters revealed a significant positive correlation of diatoms (Nitzschia sp., Navicula sp., Cyclotella meneghiniana and Stauroneis sp) with nitrate, phosphate and lead at sampling statins St- 2 and 6. CCA analysis revealed that the concentration of calcium, chloride, pH, alkalinity, silica, and ammonia were found to favor the occurrence of dominant species such as Cymbella turgiduta, Gomphonema sp., Rhopalodia sp., in St-3 and St-4. Among all ponds, certain parameters like total alkalinity, nitrite, phosphate, sodium, cobalt, potassium perhaps reflect the influence of agricultural waste, sewage waste, or anthropogenic activities. The statistical indices in coherence with the dominance of pollution indicator species such as Nitzschia palea, Melosira granulata and Cyclotella meneghiniana revealed that the stations St-2, 4 and 6 were heavily polluted, whereas St- 1, 3 and 5 were less polluted.

Structure evolution, properties and synthesis mechanism of ultra-lightweight eco-friendly ceramics prepared from kaolin clay and sewage sludge

At present, the problem of pollution and re-pollution caused by sewage sludge stacking at random has become increasingly serious in many regions and countries including China, which requires and stimulates researchers to explore more industrially feasible options to reduce environmental and eco-economic problems related to the current sludge management. In this work, an ultra-lightweight and eco-friendly ceramic (UEC) was synthesized from waste sewage sludge (SS) and kaolin clay (KC). By changing proportion of SS to KC, the mineral species, structure evolution, physical-mechanical properties, heavy metal risk assessment and sintering mechanism of UEC specimens were investigated. The results showed that the change of SS content did not vary the mineral species of UEC specimens, which all contained five mineral components: mullite (Al6Si2O13), sillimanite (Al2SiO5), hematite (Fe2O3), cristobalite (tetragonal SiO2) and aluminum iron phosphate (Al0.67Fe0.33(PO4)), but influenced their structure and performance. As the SS content increased from 20 to 50 wt%, the UEC specimen structure became denser and the inner pores grew continuously due to the increase of gas and glassy liquid phase. Meanwhile, the linear shrinkage, mass loss and bulk density also increased continuously, with corresponding maximum values of 18.59%, 30.45% and 1.92 g/cm3, respectively. Whereas the apparent porosity decreased significantly, and its value varied from 39.32% to 17.50%. Among all UEC specimens, the UEC-30 (SS/KC=30/70) and UEC-40 (SS/KC=40/60) had the most promising compressive strength (120 MPa) and bending strength (66 MPa), respectively. Also, the heavy metal leaching results of UEC specimens revealed that the final developed ceramic products were safe and non-toxic.

Physico-Chemical and Micro-Biological Characteristics of Sewage Waste Water in Khammam City, Telangana, India

Physico-Chemical and Micro-Biological Characteristics of Sewage Waste Water in Khammam City, Telangana, India

Facing marine debris in China.

China is one of the largest waste importers and producers in the world, with land-based discharges mainly from domestic sewage and industrial wastes being the main source of marine debris (MD) including three distributional types as stranding on the beach (BMD), floating on the water surface (FMD), and submerging into sediments (SMD). Fishery-related activities are also one of the main sources of marine debris: intensive aquaculture, fishing, and related household activities. Marine debris, showing different ways of leaching, degradation and fragmentation, can be ingested, incorporated and accumulated by marine organisms through the food chain, and ultimately pose risks to the ecological environment, economic benefits and human health. Comprehensive countermeasures, from awareness to practices and from the government to the public, are now being implemented in China and have achieved remarkable results especially in domestic waste incineration, but greater commitment and stronger execution are urgently required.

Physico-Chemical and Micro-Biological Characteristics of Sewage Waste Water in Khammam City, Telangana, India

Physico-Chemical and Micro-Biological Characteristics of Sewage Waste Water in Khammam City, Telangana, India

Assessment of natural and anthropogenic contamination sources in a Mediterranean aquifer by combining hydrochemical and stable isotope techniques

The Atalanti basin is an intensively cultivated area in central Greece, facing groundwater quality deterioration threats due to natural and anthropogenic-related contamination sources. A combination of statistical and hydrogeochemical techniques, and stable isotope compositions (δ2H-H2O and δ18Ο-Η2Ο, δ15Ν-ΝΟ3− and δ18Ο-ΝΟ3−, δ34S-SO42− and δ18O-SO42−) were applied to elucidate the origin of salinity and nitrate contamination, and shed light on the potential associations between geogenic Cr(VI) and NO3− sources and transformations. Nitrate and Cr(VI) concentrations reached up to 337 mg L−1 and 76.1 μg L−1, respectively, exceeding WHO threshold values in places. The cluster of samples with the high salinity was mostly influenced by irrigation return flow and marine aerosols, and less by seawater intrusion, as evidenced by the ionic ratios (e.g., Na+/Cl−) and the stable isotopes of oxygen and hydrogen in water, and sulphur and oxygen in sulphates. The δ15Ν-ΝΟ3− and δ18O-NO3− values ranged from +2.0 ‰ to +14.5 ‰ and + 0.3 ‰ to +11.0 ‰, respectively. We found that the dominant sources of NO3− in groundwater were fertilizers in the central part of the area and sewage waste in the northern part around the residential area of Livanates. The occurrence of denitrification was evident in the northern part of the basin, where the DO levels were lowest (≤ 2.2 mg L−1), whereas nitrification of NH4+-fertilizers prevailed in the central part. Elevated Cr(VI) values (≥ 20 μg/l) were associated with the lowest deviation of the measured from the theoretical nitrification δ18Ο-NO3− values, whereas the lowest Cr(VI) values were observed in the denitrified water samples. Our isotope findings revealed the strong influence of redox conditions on the biogeochemical transformations of N species and the mobilization of Cr(VI) that will help improve the understanding of the fate of these contaminants from the unsaturated zone to the groundwater in areas of agricultural and urban land use.

A multi-time scale dispatching optimal model for rural biomass waste energy conversion system-based micro-energy grid considering multi-energy demand response

Aiming at utilizing straw, garbage, domestic sewage and other biomass waste resources in rural areas, this study designed a rural biomass wastes energy conversion system (BWs)-based micro energy grid (BWs-MEG), and the mathematical modeling of BWs-MEG is carried out including multi-energy transforms system (METS) and multi-energy demand response (MEDR). Then, a two-stage optimal framework for rural BWs-MEG multi-time scale dispatching is designed. In the day-ahead stage, a multi-objective dispatching optimal model was constructed with the objectives of minimum operating costs and maximum eco-environment benefits. In the intra-day stage, the robust optimization theory was utilized to characterize the uncertainties of wind power plant (WPP) and photovoltaic power generation (PV) and a rolling dispatching optimal model was constructed with the objective of minimum deviation costs. After that, the above dispatching model was fuzzified and linearized, and then converted into a mixed integer linear programming model. Finally, a micro-energy grid in northern China was selected as an example for case study. The results showed: (1) BWs can utilize rural biomass waste resources for pyrolysis power generation (PG) and gas production to achieve energy utilization and provide power, heating and gas output. In the islanded operation mode and grid-connected operation mode, when MEG is configured with BWs, the deviation costs decrease by 25.6 % and 26.33 %, while the operating costs increases only by 7.60 % and 13.52 %, respectively. The power output of WPP and PV increase by 1.03 % and 2.19 % in the grid-connected operation mode, indicating that BWs is conducive to realizing the multi-dimension supply and demand balance of power, heating and gas loads. (2) Multi-time scale dispatching model can give play to the regulation ability of BWs, METS and MEDR and connect the day-ahead dispatching plan with the intra-day dispatching strategy to formulate the optimal dispatching strategy. When there is deviation in the day-ahead dispatching strategy, METS and MEDR could maintain the supply and demand balance of power load. AHP can change the heating period and BWs could maintain the supply and balance of heating and gas loads. Compared with the day-ahead dispatching plan, the output of PG and power-to-gas device in intra-day dispatching strategy increase by 21.22 % and 9.78 %. (3) Robust stochastic optimization method can characterize the uncertainties of WPP and PV and formulate the dispatching decision schemes with different risk attitudes. With the robust coefficient Г increasing, MEG operating costs and eco-environment benefits increase and deviation adjustment costs decreases, but the robustness of the dispatching scheme is improved. When 0.25≤Г≤0.75, the increase of the uncertainty parameter will have a direct impact on the formulation of dispatching scheme. And the decision maker belongs to risk preference type, who is willing to take certain risks to win excess benefits. Besides, if MEG operates in the grid-connected mode, the uncertainty risks will be weakened and the operation mode shall be reasonably selected according to the demand for dispatching decision. Overall, the proposed optimization model can promote the energy utilization of rural biomass waste resources, which is conducive to the realization of a clean and low-carbon transformation of the overall energy structure.

Kampung Muram Sari sebagai Basis Pengembangan Ternak Kambing di Kabupaten Merauke

Muram Sari Village is one of the villages in the Semangga District, Merauke Regency with the largest population in the Semangga District. This village is dominated by transmigration communities who in fact have a livelihood as farmers and ranchers. One of the livestock developed is goat which is considered to be able to help boost the economy of farmers from generation to generation. Goat farming is currently being cultivated by breeders, although its implementation has not been fully maximized. This is due to the lack of understanding of breeders on the development of goats, the maintenance system is still traditional and the maintenance management and group management are not optimal. Therefore, with the Community Partnership Service (PKM) activity, the implementing team will provide full participation in solving problems faced by the group, especially cultivation management, housing systems, group management, and processing of sewage waste as organic fertilizer. It is hoped that in the future, Muram Sari Village will become the basis for developing goats in Merauke Regency.

Heavy metal contamination in beach sediments as a result of sewage outlet and waste residue dumping in Qingdao, China.

Heavy metal pollution on beaches due to enhanced human activities has received attention. This study takes four beaches in China as examples to study the characteristics of heavy metal pollution. The results show that most beach sediments have a certain degree of heavy metal accumulation as a result of human activities, except for the sediments of No. 1 beach. The beaches in order of the degree of pollution were No. 3 beach > Shilaoren beach > No. 2 beach > No. 1 beach. Three of the four studied beaches show contamination with As, Cr, Fe, Ni, Pb and Zn. Sewage outlets are the main sources of these pollutants, but the high levels of Zn and Fe are caused by coal cinder dumping at one beach, and the high levels of Ni are due to the coating of fishing boats at another beach. Heavy metal pollution occurs in areas near pollutant sources or at the high or low tide lines due to waves and tides. Heavy metals also diffuse vertically, resulting in contamination at certain depths. The distribution of heavy metals over ten years showed that most of the pollutants on cape-bay beaches are difficult to diffuse outward, which indicates that a special pollutant management plan needs to be developed for such beaches.

Fluorescence "Turn-off" Sensing of Iron (III) Ions Utilizing Pyrazoline Based Sensor: Experimental and Computational Study.

A simple pyrazoline-based ''turn off'' fluorescent sensor 5-(4-methoxyphenyl)-3-(5-methylfuran-2-yl)-1-phenyl-4,5-dihydro-1H-pyrazole (PFM) was synthesized and well characterized by different techniques such as FT-IR, 1H-NMR, 13C-NMR, and mass spectrometry. The synthesized sensor PFM was utilized for the detection of Fe3+ ions. Fluorescence emission selectively quenched by Fe3+ ions compared to other metal ions (Mn2+, Al3+, Fe2+, Hg2+, Cu2+, Co2+, Ni2+, Cd2+, Pb2+, and Zn2+) via paramagnetic fluorescence quenching and showed good anti-interference ability over the existence of other tested metals. Under optimum conditions, the fluorescence intensity of sensor quenched by Fe3+ in the range of 0 to 3μM with detection limit of 0.12μM. Binding of Fe3+ ions to PFM solution were studied by fluorescent titration, revealed formation of 1:1 PFM-Fe metal complex and binding constant of complex was found to be of 1.3 × 105M-1. Further, the fluorescent sensor has been potentially used for the detection of Fe3+ in environmental samples (river water, tap water, and sewage waste water) with satisfactory recovery values of 99-101%.

Farmers’ Preferences for Fertilizers derived from Domestic Sewage and Kitchen Waste – A Discrete Choice Experiment in Germany

In view of increasing energy and resource scarcities, nutrient recycling from domestic wastewater is a promising way to obtain mineral fertilizers. Given the lacking evidence about the acceptance of recycling fertilizers by the farming sector, we elicited farmer preferences and willingness to pay (WTP) for selected attributes of mineral fertilizers made from domestic sewage and kitchen waste. We conducted a Discrete Choice Experiment with 206 German farmers and fitted a Random Parameter Logit (RPL) model. As-suming an average market price level of around 300 euros per tonne of N-P-K fertilizer, the choice exper-iment revealed that farmers not engaged in non-food production such as forage cultivation or renewable energies activities and without farmer-to-consumer direct marketing would accept a recycling fertilizer only together with a financial compensation via price discount of approximately 10%. The average WTP drops considerably if a fertilizer’s heavy metal contents are relatively high and if the absence of drug residues cannot be guaranteed, whereas a customizable nutrient composition and a constant supply availability would have a sales promoting effect. Farmers’ characteristics can only partly explain the notable heterogeneity of the WTP for the considered fertilizer attributes. Even though the WTP for a recycling fertilizer is on average less than that for a conventional mineral fertilizer, the estimated WTP standard deviations suggest that not all farmers expect a financial compensation via price discount when purchasing recycling fertilizers.