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[Display omitted] • C. vulgaris -S395-2- C. rosea for aquaculture wastewater treatment were proposed. • Gibberellins enhances the attenuation of studied aquaculture pollutants. • Pollutant attenuation showed a high fungus strains dependence. • The maximum OTC removal efficiencies were 98.29 % ± 1.15 %. This study assessed the effect of gibberellins (GAs) concentrations on antibiotic and nutrient removal using diverse microalgal-bacterial-fungal consortia. Five systems (Chlorella vulgaris , T1; C. vulgaris + S395-2 + Clonostachys rosea, T2; C. vulgaris + S395-2 + Ganoderma lucidum , T3; C. vulgaris + S395-2 + Pleurotus pulmonarius , T4; and C. vulgaris + S395-2, T5) were established, and optimal conditions and effective symbiosis were applied to improve antibiotic and nutrient removal. Consortium growth was T2 > T3 > T5 > T4 > T1, while GA impact ranked 50 mg L–1 > 20 mg L–1 > 80 mg L–1 > 0 mg L–1. After 7 days at 50 mg L–1 GAs, total nitrogen (TN), NH 4 -N, NO 3 -N, and total phosphorous (TP) removal reached 85.97 %, 78.08 %, 86.59 %, and 94.39 %, respectively. Florfenicol, oxytetracycline hydrochloride, ofloxacin, and sulfamethoxazole removal efficiencies were 67.77 %, 98.29 %, 90.47 %, and 94.92 %, respectively. These findings highlight GAs' significant role in enhancing antibiotic and nutrient removal. [ABSTRACT FROM AUTHOR]

The intensive agricultural practices are increasing the demand for chemical fertilizers, being currently produced from a non-environmental friendly way. Besides the environmental impacts, the nutrient uptake efficiency by the crops is very low, representing huge losses into the fields. Therefore, it is crucial to study alternatives for the current chemical fertilizers, which simultaneous improve nutrient efficiency and minimize environmental impacts. A sustainable solution is to recover nutrients from wastewater streams with microalgal cultures and the biomass conversion into bio-char for soil amendment. Wastewaters are loaded with nitrogen and phosphorus and can be used as culture medium for microalgae. Thus, nutrients can be recycled, reducing the requirement of chemical fertilizers. This paper aims to review nutrient recovery from wastewater using microalgae and the biomass conversion into bio-char. This process promotes nutrient recycling and the bio-char (when added to soil) improves the nutrient uptake efficiency by crops. [ABSTRACT FROM AUTHOR]

• ΣOMP degradation of 99% in water and 55% in urine after 80 min UV-AOP (2100 J m-2). • Energy demand to degrade OMPs in urine was 10-fold higher than in Milli-Q water. • Organic compounds in urine compete with OMPs for UV light and scavenge free radicals. • Nitrogen content in urine is preserved during UV AOP and can be recovered afterwards. In household wastewater, a large proportion of organic micropollutants (OMPs) load is attributed to human urine. OMPs could pose a risk to human and environmental health when urine collected in source-separating sanitation systems is recycled as crop fertiliser. This study evaluated degradation of 75 OMPs in human urine treated by a UV-based advanced oxidation process. Fresh urine and water samples were spiked with a broad range of OMPs and fed into a photoreactor equipped with a UV lamp (185 and 254 nm) that generated free radicals in situ. Degradation rate constant and the energy required to degrade 90% of all the OMPs in both matrices were determined. At a UV dose of 2060 J m-2, average ΣOMP degradation of 99% (±4%) in water and 55% (±36%) in fresh urine was achieved. The energy demand for removal of OMPs in water was <1500 J m-2, but for removal of OMPs in urine at least 10-fold more energy was needed. A combination of photolysis and photo-oxidation can explain the degradation of OMPs during UV treatment. Organic substances (e.g. urea, creatinine) likely inhibited degradation of OMPs in urine by competitively absorbing UV-light and scavenging free radicals. There was no reduction in the nitrogen content of urine during treatment. In summary, UV treatment can reduce the load of OMPs to urine recycling sanitation systems. [Display omitted] [ABSTRACT FROM AUTHOR]

The suitability of crude and purified struvite (MgNH 4 PO 4 ), a major precipitate in wastewater streams, was investigated for renewable replacement of conventional nitrogen and phosphate resources for cultivation of microalgae. Bovine effluent wastewater stone, the source of crude struvite, was characterized for soluble N/P, trace metals, and biochemical components and compared to the purified mineral. Cultivation trials using struvite as a major nutrient source were conducted using two microalgae production strains, Nannochloropsis salina and Phaeodactylum tricornutum , in both lab and outdoor pilot-scale raceways in a variety of seasonal conditions. Both crude and purified struvite-based media were found to result in biomass productivities at least as high as established media formulations (maximum outdoor co-culture yield ∼20 ± 4 g AFDW/m 2 /day). Analysis of nutrient uptake by the alga suggest that struvite provides increased nutrient utilization efficiency, and that crude struvite satisfies the trace metals requirement and results in increased pigment productivity for both microalgae strains. [ABSTRACT FROM AUTHOR]

• A novel bioprocess is proposed for municipal wastewater treatment. • Sewage treatment can be with positive financial output. • Nutrients can be effectively recovered. • Recovering methane from effluent of AnMBR is important and feasible. • Much less excess sludge production can be achieved. Conventional sewage treatment applying activated sludge processes is energy-intensive and requires great financial input, hampering widespread implementation. The introduction of anaerobic membrane bioreactors (AnMBR) followed by an algal reactor growing species of commercial interest, may present an alternative, contributing to the envisaged resource recovery at sewage treatment plants. AnMBRs can be applied for organic matter removal with energy self-sufficiency, provided that effective membrane fouling management is applied. Haematococcus pluvialis , an algal species with commercial value, can be selected for ammonium and phosphate removal. Theoretical analysis showed that good pollutant removal, positive financial output, as well as a significant reduction in the amount of hazardous activated sludge can be achieved by applying the proposed process, showing interesting advantages over current sewage treatment processes. Microbial contamination to H. pluvialis is a challenge, and technologies for preventing the contamination during continuous sewage treatment need to be applied. [ABSTRACT FROM AUTHOR]

Abstract: High biomass productivity and efficient harvesting are currently recognized challenges in microbial biofuel applications. To produce naturally settleable biomass, combined growth of native microalgae and bacteria was facilitated in laboratory sequencing batch reactors (SBRs) using primary treated wastewater from the Christchurch Wastewater Treatment Plant (CWTP) in New Zealand. SBRs were operated under a simulated, local, summer climate (i.e., 925 μmol/m2/s of photosynthetically active radiation for 14.7 h per day at 21 °C mean water temperature) using 1.4- to 8-day hydraulic retention times (HRTs) to optimize growth. Solids retention times (SRTs) were varied from 4 to 40 days by discharging different ratios of supernatant and completely mixed culture. Biomass productivity up to 31 g/m2/day of solids was obtained, and it generally increased as retention times decreased. Biomass settleability was typically 70–95%, and the microbes aggregated into compact flocs as cultures aged up to four months. Due to a low lipid content of 10.5%, anaerobic digestion appeared to be the most appropriate biofuel conversion process with potential to generate 19,200 m3/ha/yr of methane based on settleable mixture productivity. [Copyright &y& Elsevier]

Abstract: This chapter describes the possibility to combine wastewater treatment in recirculating aquaculture systems (RAS) with the production of crop plants biomass. In an aquaponic RAS established in Waedenswil, Zurich, the potential of three crop plants was assessed to recycle nutrients from fish wastewater. A special design of trickling filters was used to provide nitrification of fish wastewater: Light-expanded clay aggregate (LECA) was filled in a layer of 30 cm in vegetable boxes, providing both surface for biofilm growth and cultivation area for crop plants. Aubergine, tomato and cucumber cultures were established in the LECA filter and nutrient removal rates calculated during 42–105 days. The highest nutrient removal rates by fruit harvest were achieved during tomato culture: over a period of >3 months, fruit production removed 0.52, 0.11 and 0.8 gm−2d−1 for N, P and K in hydroponic and 0.43, 0.07 and 0.4 gm−2d−1 for N, P and K in aquaponic. In aquaponic, 69% of nitrogen removal by the overall system could thus be converted into edible fruits. Plant yield in aquaponic was similar to conventional hydroponic production systems. The experiments showed that nutrient recycling is not a luxury reserved for rural areas with litlle space limitation; instead, the additionally occupied surface generates income by producing marketable goods. By converting nutrients into biomass, treating wastewater could become a profitable business. [Copyright &y& Elsevier]

Source-separating sanitation systems offer the possibility of recycling nutrients present in wastewater as crop fertilisers. Thereby, they can reduce agriculture's impacts on global sources, sinks, and cycles for nitrogen and phosphorous, as well as their associated environmental costs. However, it has been broadly assumed that people would be reluctant to perform the new sanitation behaviours that are necessary for implementing such systems in practice. Yet, few studies have tried to systematically gather evidence in support of this assumption. To address this gap, we surveyed 3763 people at 20 universities in 16 countries using a standardised questionnaire. We identified and systematically assessed cross-cultural and country-level explanatory factors that were strongly associated with people's willingness to consume food grown using human urine as fertiliser. Overall, 68% of the respondents favoured recycling human urine, 59% stated a willingness to eat urine-fertilised food, and only 11% believed that urine posed health risks that could not be mitigated by treatment. Most people did not expect to pay less for urine-fertilised food, but only 15% were willing to pay a price premium. Consumer perceptions were found to differ greatly by country and the strongest predictive factors for acceptance overall were cognitive factors (perceptions of risks and benefits) and social norms. Increasing awareness and building trust among consumers about the effectiveness of new sanitation systems via cognitive and normative messaging can help increase acceptance. Based on our findings, we believe that in many countries, acceptance by food consumers will not be the major social barrier to closing the loop on human urine. That a potential market exists for urine-fertilised food, however, needs to be communicated to other stakeholders in the sanitation service chain. Willingness to eat human urine fertilised food across the surveyed countries. Overall, 59% of respondents said they were willing to eat food grown using human urine as fertiliser, but in specific countries, stated willingness ranged from very low (14%) to high (80%). Unlabelled Image • 3763 people surveyed to understand willingness to eat human urine-fertilised food • Cross-cultural & country-level factors explanatory of respondent attitudes identified. • Respondents had positive intention overall but were unwilling to pay price premiums. • Social norms and cognitive awareness of urine's benefits & risks featured strongly • Building consumer trust via context-specific messaging can improve acceptance of urine recycling. [ABSTRACT FROM AUTHOR]

Technologies to remove nitrogen from wastewater are employed to preserve drinking water and prevent environmental damage. Nitrification/denitrification and partial nitrification-anammox are two accepted nitrogen removal techniques for wastewater treatment plants. These processes require energy for aeration and can release fugitive greenhouse gases in the form of nitrous oxide. Electrodialysis could potentially be used as an alternative to remove ammonium from waste streams, but previous experimentation has concluded that concentrate streams experience rapid scaling and fouling of membranes. This analysis compiles literature values to compare the state-of-the-art of municipal nitrogen removal to the new electrodialysis technique on an economic basis. Results show that nitrogen removal and recovery by electrodialysis is estimated to lower both initial capital costs and subsequent operation costs than traditional N removal technologies. Image 1 • Modeled electrodialysis ammonium recovery on municipal sludge digester reject water. • Developed optimization method based on stack cost and influent conditions. • Electrodialysis estimated to be less expensive than existing N removal technologies. • Cost differences come primarily from inexpensive and compact installation. [ABSTRACT FROM AUTHOR]

• Inorganic fertilizers account for 42 % of N and 90 % of P inputs to Ontario's food systems. • Ontario loses 298 kt-N/y (58 %) and 15 kt-P/y (29 %) of annual inflow to the environment. • Cropland erosion contributes 103 kt-N/y (35 %) and 14 kt-P/y (90 %) of total N and P losses. • A 30 % simulated increase in diversion rates reduced reliance on inorganic fertilizer by 28 kt-N/y and 9 kt-P/y. • Food waste, manure and biosolids management require technological and policy interventions. Resource scarcity, energy requirements, and environmental pollution resulting from the production and use of nitrogen (N) and phosphorus (P) fertilizer have spurred an interest in a circular approach to nutrient management. An analysis of N and P flows in Ontario's food systems was carried out to quantify relevant flows and stocks, evaluate alternative management scenarios and identify points of loss to the environment. The results showed that mineral fertilizers accounted for 42 % of N and 90 % of P inputs to Ontario's food systems. Of the total amount of food produced, 153 kt-N/y ± 27 % and 28 kt-P/y ± 21 % in grain and oilseed were fed to animals. About 58 % (298 kt-N/y) and 29 % (15 kt-P/y) of the annual supply of N and P were lost to the environment. Major nutrient losses were from the crop production system, through erosion, contributing 35 % (103 kt-N/y ± 10 %) and 90 % (14 kt-P/y ± 51 %) of the total N and P lost. Over half of the N and P in the waste subsystem was disposed of in landfills or incinerators, where further N losses occurred through leaching and volatilization. Ontario's reliance on inorganic fertilizer supply could reduce by 28 kt-N/y and 9 kt-P/y if the current waste diversion rates were to increase by 30 %. No single waste management scenario could effectively circularize N and P flows in Ontario's food system. However, investment in new technologies might help to recover nutrients from manure and wastewater treatment systems efficiently. [ABSTRACT FROM AUTHOR]