Fruit and vegetable wash-water characterization, treatment feasibility study and decision matrices

Abstract

On average, it is estimated that up to 5 liters of wastewater is generated per kg of produce in postharvest processing of fruit, leafy greens and root vegetables. The typical wastewater parameters vary in concentration (solids content, COD, BOD, nitrogen, phosphorus) based on the produce being processed. The challenge for producers and regulators is that the selection of the appropriate treatment technology is challenging, so decision matrices were developed to narrow down the treatment selections. Wash-waters for different types of fruit and vegetables from two different operation types, washing only vs. washing and processing. Bench-scale treatments selected for testing included settling, coagulation and flocculation with settling, centrifuge, dissolved air flotation, electrocoagulation, screening, and hydrocyclone. The developed decision matrices summarize the removal effectiveness of the different treatments for typical wastewater parameters and serve as a reference tool in understanding wash-water treatment technologies and their effectiveness in treating various wash-waters.

Soil erosion on arable land: An unresolved global environmental threat

“…In the second case, soil ends up at the food processing plant, which may be on or off farm. Here, typically, the soil is removed from the crops by washing with potable water which is then treated and disposed of (Mundi et al, 2017). The variation in the treatment of harvested root crops makes harvest erosion difficult to quantify as it requires individual farm and food chain specific analyses to estimate.…”

Interactions between Microbial Food Safety and Environmental Sustainability in the Fresh Produce Supply Chain

“…Apart from water consumption, the use of water also involves the consumption of energy for cooling, heating, or pumping [ 61 ]. Mundi et al [ 62 ] indicated that one kilogram of processed fruit and vegetables entails the generation of 5 L of wastewater; its characteristics depend on factors such as the type of processed product, and the configuration and management of the processing lines. In the case of fresh-cut produce processing plants, 2 to 11 m 3 of good-quality water is consumed per ton of product [ 63 ], although a significant part of this water is commonly reconditioned and reused to reduce water consumption and wastewater generation [ 64 ].…”

Machine Learning Models for Predicting Water Quality of Treated Fruit and Vegetable Wastewater

“…Similarly, CODRaw is normalized, and the value is 0.0133. The next step is to look up the process value for W type process from Table 1 for the BODTreated model, which is 1, The developed models, which complement the treatment decision matrices/tables produced in Mundi et al [24], show the level of treatment expected from various washwaters/wastewaters. The decision matrices/tables provided a range for treatment effectiveness, while these models extend that analysis to numerical models for more flexible treatment predictions.…”

“…In addition, the products were also classified as a root vegetable, tree fruit, leafy green, and above ground. The full dataset consists of four independent subsets, two of which were studied and presented in Mundi et al [24], while the remaining two were introduced for characterization in Mundi et al [25], which were collected by the Ontario Ministry of Agriculture Finance and Rural Affairs (OMAFRA). The results presented in Mundi et al [24] were table-based or decision matrices, where the user would read the treatment combination of the charts.…”

“…These include the following treatments: Settling (jar test control-1 min rapid mix at 100 rpm, 10 min slow mix at 30 rpm, and 20 min settling), settling with a coagulation and flocculation process (jar test with coagulants varying in dosage from 5 to 400 mg/L, 1 min rapid mix at 100 rpm, 10 min slow mix at 30 rpm, and 20 min settling), screening (sieve 100 um), centrifugation (1801 × G for 3-min), dissolved air flotation (10-min retention of recycling water at a rate of 50% and 10-min detention for flotation) using an optimized coagulant dosage as determined earlier using the jar test, hydro-cyclone (4 mm apex, 6.7 mm vortex finder, 48 mm diameter, and 1.3 L/min of flow), and electrocoagulation (Maximum of 575.1 cm 2 surface area, minimum reaction time of 10-min, and maximum of 0.27 kWh/m 3 power consumption). A detailed description of bench-scale treatments and their methodology, in addition to full-scale treatments, are outlined in Mundi et al [24].…”