A Systematic Review on Pistachio Processing Industry Wastewater (Ppw): Composition, Environmental Impacts, and Treatment Options Publisher



Abbasnia A ; Soleimani H ; Bahlgerdi M ; Oskoei V ; Bazrafshan E
Source: Water, Air, and Soil Pollution Published:2026

Abstract

Pistachio processing wastewater (PPW) is a high-strength agro-industrial effluent that poses a threat to receiving waters and soils, particularly in arid pistachio-producing regions. Generated at roughly 4–6 m3 per ton of processed nuts, PPW carries extreme pollutant loads—chemical oxygen demand (COD) up to 23,500 mg/L and total phenolics of 1,750 – 4,100 mg L⁻1—together with elevated turbidity, TOC, TSS, nitrogen species, chloride, and oil and grease. This systematic review synthesized 15 peer-reviewed studies (to March 2025) on PPW characterization and treatment performance. Electrochemical processes—especially electro-coagulation and electro-oxidation—consistently removed up to ~ 99% of COD and phenolics, but with notable energy and cost considerations. Advanced oxidation routes (e.g., Fenton and subcritical water oxidation) rapidly degraded persistent organics and clarified effluents, yet typically required energy-intensive operating windows. Biological approaches, most prominently UASB anaerobic digestion, achieved ≈90% COD removal while enabling energy recovery with methane yields near 332 mL CH₄ g⁻1 COD. Hybrid trains that couple fungal bioprocesses, membranes, or physicochemical steps further enhanced removal, reduced sludge, and opened pathways for resource recovery. Evidence across studies highlights high variability in PPW composition and emphasizes that no single technology suffices; instead, robust, low-energy, and adaptable treatment trains are needed. Future priorities include pilot- and full-scale validation under real-world fluctuations, life-cycle and techno-economic assessment, risk-based discharge criteria for soil–water protection, and circular-water strategies that pair safe effluent reuse with valorization of by-products (biogas, phenolics) to support sustainable pistachio processing. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2026.