Re-emergence of dry toilets and fecal nutrient reuse in M'zab cities

In the M'zab valley, dry toilets represent an ancestral dry sanitation system, serving as a source of fertilizer thanks to human excrement valorization. However, in the 20th century, local populations began to shun these systems. The objective of this article is to illustrate the importance of dry toilets on agricultural and environmental scales in ancient M'Zab, and the renewal of these systems in response to sanitation problems in the oasis after their decline. The hypothesis put forward is that dry toilets can act as a complementary system to conventional sanitation systems. Data were collected through interviews with the local population. Our results show that the use of dry toilets, and the resulting use of human excrement as fertilizer, has gone through three phases. First, a phase of strong recycling dynamics, followed by a second phase of decline in dry toilet use which is linked to the discovery of the Albian aquifer and flush toilet adoption. The third phase is characterized by dry toilet reuse in response to oasis degradation caused by sanitation and environmental problems. Some oasesians have taken the initiative to revert to dry toilets to ensure oasis system sustainability and to revive the practice of recycling human waste.

Lysosome Depletion-Triggered Autophagy Impairment in Progressive Kidney Injury

<b><i>Background:</i></b> Macroautophagy (autophagy) is a cellular recycling process involving the destruction of damaged organelles and proteins in intracellular lysosomes for efficient nutrient reuse. <b><i>Summary:</i></b> Impairment of the autophagy-lysosome pathway is tightly associated with multiple kidney diseases, such as diabetic nephropathy, proteinuric kidney disease, acute kidney injury, crystalline nephropathy, and drug- and heavy metal-induced renal injury. The impairment in the process of autophagic clearance may induce injury in renal intrinsic cells by activating the inflammasome, inducing cell cycle arrest, and cell death. The lysosome depletion may be a key mechanism triggering this process. In this review, we discuss this pathway and summarize the protective mechanisms for restoration of lysosome function and autophagic flux via the endosomal sorting complex required for transport (ESCRT) machinery, lysophagy, and transcription factor EB-mediated lysosome biogenesis. <b><i>Key Message:</i></b> Further exploring mechanisms of ESCRT, lysophagy, and lysosome biogenesis may provide novel therapy strategies for the management of kidney diseases.

Nutrient Recovery from Agricultural Wastewater by Integrated Electrokinetic Processes

&lt;p&gt;Agricultural wastewater including anaerobic digestate is annually generated in a huge quantity in Taiwan. The management of agricultural wastewater should be emphasized on the recovery and production of value-added resources, such as macronutrients (nitrogen, phosphorus, and potassium), for realizing the circular bioeconomy. In this paper, we will illustrate the development of energy-efficient electrokinetic processes for nutrient recovery from agricultural wastewater. First, we evaluate the performance of electrokinetic separations processes for recovery of macronutrients. We also discuss major challenges in managing nutrient reuse by the developed electrokinetic methods. Then, we elucidate the process chemistry and reaction kinetics by the processes. Lastly, we consider the interconnectivity among water, energy and the produced macronutrients in the context of large-scale deployment.&lt;/p&gt;

Development of a natural treatment system consisting of red ball earth and alfalfa for the post-treatment of anaerobically digested livestock wastewater

With the objective of developing a post-treatment process for anaerobically digested livestock wastewater, an innovative natural treatment system composed of two units is proposed. The first trickling filter unit further reduced biochemical oxygen demand and achieved a certain degree of nitrification. The second soil-plant unit was targeted at the removal and recovery of nutrients N, P and K. For the feasibility study, a bench-scale soil column test was carried out, in which red ball earth and alfalfa were utilized for treating synthetic nutrient-enriched wastewater. Through long-term operation, the nitrification function was well established in the top layers, especially the top 20 cm, although a supplementary denitrification process was still required before discharge. P and K were retained by the soil through different mechanisms, and their plant-available forms that remained in the soil were considered suitable for indirect nutrient reuse. As for alfalfa, with wastewater application it fixed more N from the atmosphere, and directly recovered 6% of P and 4% of K input from wastewater. More importantly, alfalfa was verified to have an indispensable role in stimulating the soil nitrifying microorganisms by sustaining their abundance during substrate (NH3) and oxygen scarcity, and enhancing cell-specific nitrification potential during substrate (NH3) and oxygen sufficiency. The proposed system is expected to be further improved, and adopted as a sound countermeasure for livestock wastewater pollution.

Membrane bio-reactors for decentralized wastewater treatment and reuse

Decentralized wastewater treatment is the key to sustainable water management because it facilitates effluent (and nutrient) reuse for irrigation or as service water in households. Membrane bioreactors (MBR) can produce effluents of bathing water quality. Septic tanks can be retrofitted to MBR units. Package MBR plants for wastewater or grey water treatment are also available. Systems for decentralized treatment and reuse of domestic wastewater or grey water are also feasible for hotels, condominiums and apartment or office complexes. This paper presents the effluent qualities of different decentralized MBR applications. The high effluent quality allows infiltration even in sensitive areas or reuse for irrigation, toilet flushing and cleaning proposes in households. Due to the reusability of treated water and the possibility to design the systems for carbon reduction only, these systems can ideally and easily serve to close water and nutrient loops.