Biological Oxygen Demand Reduction Research Articles

Bacteria Associated with Degradation of Wastes from Rubber Processing Industry

An investigation of bacteria found in rubber processing wastes was carried out. Rubber wastes which include effluents from washing tanks and natural rubber waste serum (NRWS) were obtained from Greenpark Rubber Industries Limited, Umutu, Delta State, Nigeria. Five bacterial species were isolated from the wastes. These include Arthrobacter sp., Bacillus sp., Lactobacillus sp., Psuedomonas sp. and Streptococcus sp. Apart from these a number of coliforms were also encountered. Arthrobacter sp. was found to be the dominant species and its potential to utilize rubber hydrocarbon was determined. It was found that the growth of Arthrobacter in both effluent and NRWS was related to pH with the highest growths recorded at pH of 8.5 and 7.5 for effluent and NRWS respectively. It was also found that at controlled pH of 7.5 in NRWS, the growth of Arthrobacter was consistent and was accompanied by a reduction in biological oxygen demand (BOD) which was the the main index for measuring pollution strength of the wastes. It is therefore being recommended that rubber wastes be treated with Arthrobacter under controlled pH to reduce their pollution potentials before disposal. It is however suggested that a combined biological treatment using both Arthrobacter and Mucor as was earlier suggested be used. It is also recommended that chemical flocculants should be used to remove suspended solids in the effluent. A combination of these two cheap methods will go a long way in alleviating the problems of pollution caused by rubber effluents from some tropical rubber processing factories.

Removal of Indicator Microorganisms in Wastewater Reservoir in Relation to Physico-Chemical Variables

Wastewater effluent in Israel was sampled in six reservoirs during different seasons. All the reservoirs were tested for biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), light transmission, temperature, pH, dissolved oxygen (DO), chlorophyll - a, phytoplankton, Zooplankton, as well as microbiological indicators (E.coli. enterococci, heterotrophic bacteria and F+ bacteriophages). The mean reduction of COD, BOD and TSS was 72%, 76% and 45%, respectively and the mean levels at the entrances to the reservoirs were 380 mg/l, 230 mg/l, and 265 mg/l, respectively. The percent reduction of the various microorganisms tested at the entrance to the reservoir and in the reservoir itself ranged between 83.2% and 99.98%. Significant correlation coefficients were found between the concentrations of the various microbiological indicators tested, as well as between the number of indicator microorganisms and pollution parameters (BOD, COD and TSS). A good correlation was found between BOD vs. COD, BOD vs. TSS, and TSS vs. COD. From this preliminary study it may be concluded that a) storage of wastewater in the reservoirs improves the quality of the effluent, and b) changes in physico-chemical parameters and the concentration of enteric microorganisms are significantly correlated.

Biobleaching of Pulp and Paper Mill Effluents by Phanerochaete chrysosporium

AbstractThe potential of white rot fungi, namely, Polyporus versicolor FRI 165, Polyporus hirsutus FRI 534, Polyporus hirsutus FRI 2862, Phanerochaete chrysosporium BKMF 1767 and Sporotrichum pulverulentum for the reduction of colour of pretreated pulp and paper mill effluents under sterilised and unsterilised conditions has been evaluated. Of these, P. chrysosporium BKMF 1767 cultured under sterilised conditions supported maximum colour reduction after 7 days of growth. The optimisation of the process parameters showed that the addition of nutrient sails in selective combination marginally improved the colour reduction. The 7‐day‐old growth of culture at 20% (v/v) inoculum concentration resulted in maximum decolourisation (69.6%) of the effluent with pH adjusted to 4.5 at 40°C along with more than 50% reduction in biological oxygen demand (BOD) and chemical oxygen demand (COD). The irradiation of the effluent with UV light had apparently no effect on the colour, BOD and COD reduction by P. chrysosporium.

Deep bed filtration provides triple functionality

Deep-bed filtration technology recently introduced to the British waste and water treatment industries combines solids filtration, the reduction of biological oxygen demand and denitrification capabilities in a single unit.

Carbon and nitrogen transformations in wastewater during treatment with Hydrocotyle umbellata L.

The transport of O 2 through aerial plant tissue of aquatic plants into the root zone has important ramifications on C and N transformations in wastewater. In this study, O 2 transport by pennywort ( Hydrocotyle umbellata L.) and its effects on biological oxygen demand (BOD) and nitrification were investigated for primary and secondary treated sewage effluent. The treatments included flasks sealed with a rubber stopper to serve as a control, open flasks to determine the effects of O 2 diffusion from the atmosphere, flasks with a plant held by a split-rubber stopper and open flasks with a plant. The 15N-labeled effluents were analyzed at 0, 1, 2, 4 and 8 days for dissolved O 2 (DO), BOD, total Kjeldahl N (TKN), NH 4-N and NO 3-N. The plants were analyzed for TKN. Pennywort was shown to be very effective in reducing BOD in primary sewage effluent. A 42% reduction of BOD in 4 days was attributed to O 2 transport by pennywort with an additional 30% due to oxygen diffusion from the atmosphere. Nitrification was difficult to document in either sewage effluent although 22–26% of the added 15N was not accounted for in treatments with plants and was presumably lost through denitrification.

AEROBIC DIGESTION OF RUM WASTES TO ENHANCE THE MARINE FOOD CHAIN

An experimental study has been conducted on the reduction of biological oxygen demand (BOD) and the simulataneous production of marine organisms by means of aerobic digestion of wastes from a rum distillery (mostos or rum slops) The results indicate that rum wastes can be reduced in BOD by aeration and agitation in sea water to less than 50% of the original. The resulting digestion products are suitable for growing brine shrimp (Artemia salina). The microorganisms produced appear to be natural marine organisms, and the brine shrimp are known to be valuable as a fish food. Thus this method should be beneficial to the marine food chain if the digestion products are disposed of in the sea, or it could be of possible use in marine aquaculture. Both the reduction of BOD and growth of biomass increase with pH up to a value of 8, with residence time, and with concentration of BOD and rum wastes up to a level of about 25percnt; rum waste. Toxic or inhibiting effects seem to occur at 50% rum waste. Rough estimates of digestor volumes and biomass production can be obtained based on feed conditions and the desired BOD reduction.

Fish Populations in Relation to Dissolved Oxygen in the Wisconsin River

Abstract Fish populations were sampled with an electroshocker, fyke nets, and small-mesh seine in a 309-km section of the upper Wisconsin River, where average summer dissolved oxygen concentrations at various sites ranged from less than 2 to more than 8 mg/liter. Percent sport fish, percent walleyes and yellow perch, percent Centrarchidae, number of fish species, and number of species of sport fish were all greater at sites where the average summer dissolved oxygen concentration exceeded 5 mg/liter than at sites where it was less. The results indicate that reduction of biological oxygen demand in waste effluents would benefit the sport fishery.

Computer optimization of reverse osmosis processing of soy whey with cellulose acetate modules

AbstractIn processing full‐fat soy flour to an acid‐precipitated lipid protein concentrate a byproduct whey fraction results which, because of its high biological oxygen demand, represents a serious disposal problem. Processing of food waste streams by reverse osmosis has received considerable attention because of its low theoretical energy requirement since no phase change is involved. In a previous study at this Center a mathematical model was developed for the diffusive transport of soy lipid protein concentrate whey across cellulose acetate membranes. In this study, pumping energy and power costs combined with membrane life and replacement costs were incorporated into the original model to provide a basis for optimization from an energy cost standpoint. Computer‐simulated runs were compared with experimental pilot‐plant runs, and the agreement between predicted and actual results was quite good. Water flux rates were in the range of 3 to 7 gal/ft2/day. Computer runs were used to optimize the processing of 100,000 gal/day of soy whey at 8000 ppm biological oxygen demand (BOD). Costs were at a minimum with a six‐stage tapered flow primary reverse osmosis treatment over a porous cellulose acetate membrane, followed by a six‐stage tapered flow reverse osmosis over a tighter membrane. BOD reduction was 94% at a cost of $5.45/1000 gal.

Chlorinated organics as a factor in reduced biological oxygen demand (BOD)

Abstract A demonstration that “second‐order”; chlororganics might, in part, be responsible for the BOD reduction that is observed upon chlorination of wastewater has been hampered by the inability to devise an experiment that is not complicated by other contributing factors. The current study compares the BOD enhancement for parent organic systems (phenols, benzoic acids, and anilines) against the BOD values obtained from those chlororganics known to be produced from the parent during disinfection. The investigation supports the hypothesis that these chlorinated organic materials are not readily degraded during the test period and, therefore, will not provide an appropriate contribution to the overall BOD value that is obtained.

Role of heterotrophic nutrition in growth of the alga Scenedesmus obliquus in high-rate oxidation ponds.

The green alga Scenedesmus obliquus readily adapted to heterotrophic growth in the dark, utilizing glucose as the sole carbon source. Heterotrophic cells differed significantly from photoautotrophic cells with respect to several physiological properties such as the rate of photoassimilation of CO2, rate of incorporation of glucose, and chlorophyll a concentration. Oxidation pond cells shared features common to both photoautotrophic and heterotrophic cells. Approximately 15 percent of oxidation pond algal carbon was derived from glucose assimilated directly without first being oxidized by bacteria. Bacteria seem to play a minor role in biological oxygen demand reduction in high-rate oxidation ponds, and their role is probably confined to degradation of biopolymers, thus producing substrates for algal consumption.