Sequential Remediation Processes for a Low Level Pesticide Wastewater

Abstract

The aim of this study was to develop a remediation system for the treatment of a low-level pesticide wastewater that uses available onfarm organic matter as an absorption media, is capable of reducing the concentration of the pesticide to a safe level and is economically viable for implementation by farmers. The absorption capacity of chopped hay and soybean to the fungicide captan was evaluated under batch conditions and the effectiveness of the composting process in depredating captan in contaminated organic materials was evaluated. The results showed that both hay and soybean plant residues were very effective in absorbing 99.2% and 98.5% of captan form the wastewater after 4 hours, respectively. Because of its availability, hay can be used in an onfarm pesticide immobilization system that consists of shallow reinforced concrete pit (filled with hay) with steel bars across the top for machinery to roll onto and be washed. The wastewater can be retained for 24 hours which is a sufficient time for hay to absorb the captan. The contaminated hay can then be composted. The addition of used cooking oil raised the temperature of the composting mixture to 63?C. Small reductions in moisture content (from 60% to 58.9 %) and C:N ratio (from 30:1 to 28:1) were observed while reductions of 18.92%, 15.56% and 4.8% in the volatile solids, total carbon total Kjeldahl nitrogen were achieved after 10 d of composting, respectively. About 92.4% of the captan was degraded in the first 4 days of composting. Most of captan (92.4%) was degraded during the mesophilic stage (first 3 days). The degradation rate constant for the mesophilic stage (0.724 d^-1) was 2.74 times the degradation rate constant for the thermophilic stage (0.264 d^-1). An onfarm windrow composting process would be very effective in degrading captan contaminated hay. The captan contaminated hay could be mixed with equal amount poultry manure or dairy manure to provide the required bioavailable carbon and nutrients for the composting process. Some used cooking oil could also be added to maintain higher temperature within the compost matrix. The windrows should be mixed on a daily basis to provide sufficient oxygen for the composting microorganisms

Electrochemical harvesting of microalgae꞉ Parametric and cost-effectivity comparative investigation

“…On the other hand, pressure filters and vacuum filters require to be periodically replaced [29]. Sedimentation may require low power for operation but it is denoted with low separation efficiency (up to 66%) [30]. The present work showed that the target of low energy consumption and long-life parts could be met in the electrochemical harvesting process.…”

Disposal and Treatment Methods for Pesticide Containing Wastewaters: Critical Review and Comparative Analysis

“…Singh [113] reported a degradation efficiency of 96.03% for the endoslufin pesticide after 4 weeks, using composted soil with a moisture level of 38%. Al hattab and Ghaly [97] achieved a captan removal efficiency of 92.4% in the first four days using hay compost.…”

“…Memon et al [96] reported that thermally treated watermelon peels were capable of removing 99% of the methyl parathion pesticide. Al hattab and Ghaly [97] reported a captan removal efficiency of 99.2% and 98.5% using hay and soybean plant residues, respectively.…”

Kinetics of Biological Treatment of Low Level Pesticide Wastewater

“…These residues are removed from applicators by rinsing with water resulting in the formation of a toxic wastewater that represents a disposal problem for many farmers (Kearney et al, 1988). Currently, disposal of pesticide wastewater is carried out by several methods including (a) land cultivation, (b) dumping on land, in ditches, in lagoons and in soil pits and in extreme cases in sewers and streams near the rinsing operation, (c) use of evaporation ponds and (d) land filling (Al Hattab and Ghaly, 2012). These methods of disposal are totally unsafe, as the surface run off will reach streams, rivers and lakes and the infiltration of the wastewater into the local soil will eventually end up in ground water.…”

“…The treatment methods currently used for pesticide containing wastewater include (a) incineration, (b) chemical treatment such as O 3 /Uv oxidation, Fenton oxidation and hydrolysis (c) physical treatment using inorganic and organic absorbents and (d) biological treatment such as phytoremediation, composting and bioaugmentation. These treatment methods either require land or are expensive and suffer from variability of effectiveness (Balestra and Misaghi, 1997;Winterlin et al, 1989;Al Hattab and Ghaly, 2012).…”