Performance of a Constructed Wetland and Pretreatment System Receiving Potato Farm Wash Water

Growing volume of washed vegetables in Europe and Lithuania means that more drinking water is consumed and more wastewater is produced. Farmers, who engage in washing vegetables, face the problems of wastewater treatment, wastewater storage and utilization. Wastewater released to the environment from their farms would meet hygiene and environmental protection criteria. The aim of the study was to assess the contamination of the root vegetable wash water and to evaluate the possiblity of cleaning of wastewater in the land-based treatment system consisting of one constructed wetland and two biological ponds. The contamination of wastewater, produced by washed root vegetables, in Lithuanian farms was measured according to suspended solids (SS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), total nitrogen and total phosphorus. Pollution of the wash water and wastewater was evaluated comparing the mean values with legislative limit values and with typical sewage contamination values. In all farms wastewater of initial root vegetables washing was treated in settling basins. Wastewater of one carrots washing farm was treated in the land-based wastewater treatment system consisting of surface flow constructed wetland and two biological ponds. Efficiency of the wastewater treatment in this system was according to suspended solids 90%, BOD7 – 97%, CODCr – 92%, total nitrogen – 98% , total phosphorus – 97%. The result shows, that the natural wastewater treatment system is suitable for farms, that wash and produce vegetables, but before releasing wastewater to the environment, it has to be settled.

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Recycling Effects on TN and TP Mass Removal Rates in a full-Scale Subsurface Flow Constructed Wetland

Impacts of Global Climate Change ◽

10.1061/40792(173)388 ◽

2005 ◽

Cited By ~ 2

Author(s):

Steven C. Reese

Keyword(s):

Constructed Wetland ◽

Subsurface Flow ◽

Full Scale ◽

Removal Rates ◽

Mass Removal ◽

Subsurface Flow Constructed Wetland

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Brownstock washing: A review of the literature

TAPPI Journal ◽

10.32964/tj13.1.9 ◽

2014 ◽

Vol 13 (1) ◽

pp. 9-19 ◽

Cited By ~ 1

Author(s):

RICARDO B. SANTOS ◽

PETER W. HART

Keyword(s):

High Efficiency ◽

Black Liquor ◽

Material Balance ◽

Kraft Pulping ◽

Wash Water ◽

Pulp Fibers ◽

Kraft Process ◽

Cooking Process ◽

Materials Used ◽

Entrapped Air

Brownstock washing is a complex, dynamic process in which dirty wash water or weak black liquor (dissolved organic and inorganic material obtained from the pulp cooking process) is separated from pulp fibers. The use of material balance techniques is of great importance to identify potential problems and determine how well the system is operating. The kraft pulping industry was the first known to combine pulp washing with the recovery of materials used and produced in the wood cooking process. The motivation behind materials recovery is economic, and more recently, environmentally driven. The chemicals used in the kraft process are expensive as compared to those used in the sulfite process. For the kraft process to be economically viable, it is imperative that a very high percentage of the cooking chemicals be recovered. To reach such high efficiency, a variety of washing systems and monitoring parameters have been developed. Antifoam additives and processing aids have also played an important role in increasing washing effectiveness. Antifoam materials help attain washing effectiveness by preventing entrapped air from forming in the system, which allows for an easier, unimpeded flow of filtrate through the screens and washers.

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