Design concepts for biological treatment of industrial wastewater

Abstract

The design challenge for an industrial wastewater treatment system is to create a process which is capable of responding to extreme variations in flow and pollutant concentration, while maintaining the effluent within permit limitations. For example, refinery wastewater is contaminated with oil, aromatics, ammonia, phenols, sulfide, and heavy metals. The degree of contamination is related to the refinery complexity, whereas the wastewater volume is related to refinery throughput as well as complexity. Wastewater generation per barrel of crude feed is 6 to 22 gallons. (Rule of Thumb: gallons of wastewater per barrel of crude feed equals six plus 1.5 times the Nelson complexity factor). Petrochemical processes in the refinery will create additional wastewater. Pollutant concentrations undergo large excursions because of unit upsets, changes in refinery crude feed, and irregular maintenance activities. Rainfall and stormwater runoff are the dominant factors in volumetric flow variation. Figure 1 is a comprehensive flow schematic of a refinery

Biokinectic Parameter Investigation and Biological Treatment of Coffee Berry Effluents

“…The biodegradability criterion for wastewater is the ratio of COD to BOD. For domestic wastewater the ratio is about 1.6 and for industrial wastewater the ratio is usually larger than 2.5 (Capps et al 1995).This paper reports the results always as COD removal instead of BOD.…”

“…Biokinetic parameters are very important for the design of upper and lower operating limits capable of responding to variations in flow and pollutant concentrations, as pointed out previously (Ramalho 1983;Capps et al 1995). The biodegradability criterion for wastewater is the ratio of COD to BOD.…”

“…For an easily biodegradable agro-industrial wastewater, COD removal better than 80 percent is achievable. For industrial wastewater, longer residence times are usually required because of organic contaminants refractory to biodegradation (Capps et al 1995). Studies of biokinetic parameters of aerobical biological treatment yields the rate at which microorganisms degrade a specific waste, and therefore provides the basic information required for sizing biological aerobic reactors.…”

Removal of Oxygen Demand and Acute Toxicity during Batch Biological Treatment of a Petroleum Refinery Effluent

“…The BOD/COD ratio provides a simple biodegradability criterion for industrial wastewater treatment. A ratio above 0.4 indicates that the wastewater is readily biodegraded in an activated sludge process, and vice versa (Capps et al, 1995). A longer residence time, which can be achieved by longer hydraulic retention times, or the addition of an adsorbent (such as activated carbon) is required to metabolize refractory substrates (i.e.…”

“…Moreover, high sludge age is also required for the proliferation of nitrifying bacteria, if ammonia is a critical contaminant. A minimum sludge age of 40 days is recommended for effective COD and ammonia nitrogen treatment for industrial wastewater (Capps et al, 1995).…”