Trade Effluent Control: Prospects for the 1990s

The proposed privatization of the ten regional water authorities together with the accompanying reorganization of water pollution control responsibilities between the new National Rivers Authority and Her Majesty's Pollution Inspectorate, as well as the ever tightening environmental standards for the aquatic environment emanating from Brussels and from general environmental pressures, means that dischargers of industrial effluents can expect major changes both in the cost of disposing of their effluents and in terms of the legislative controls which will restrict their content.
The paper examines the various factors which will influence the management of trade effluents in the 1990s and endeavours to give some indication of what the future holds both in terms of disposal costs and environmental regulation from the point of view of the discharger.     

Incidence of heavy metal and antibiotic resistance in bacterial isolates from Blue Nile river water in Ethiopian region

Heavy metal pollution of river water has health implications. This study was aimed to test if bacteria that are heavy metal resistant can resist antibiotics. Heavy metal-resistant bacteria were isolated using Nutrient agar plates amended with 100?μg?ml^?1 of metal salts. Isolates were further screened to determine minimal inhibitory concentration against each metal. The isolates belonged to the genera of Neisseria, Bacillus, Pseudomonas, Staphylococcus, Streptococcus, Micrococcus, Corynebacterium and Proteus. Minimum inhibitory concentration of the isolates for heavy metals ranged from 200 to 2300?μg?ml^?1. Isolates of Pseudomonas, Neisseria, Bacillus, Protues, Streptococcus, Staphylococcus and Micrococcus spp. exhibited multiple antibiotic resistance. Statistically significant correlation between metal resistance and antibiotic resistance was observed among bacterial isolates. The present work suggests that some of the isolates could be hazardous to human beings as a result of natural selection of dual resistant mechanisms.     

Antibiotic resistance in coagulase negative staphylococci isolated from wastewater and drinking water

This study reports the antibiotic resistance patterns of coagulase negative staphylococci (CNS) isolated from a drinking water treatment plant (WTP), a drinking water distribution network, responsible for supplying water to the consumers (WDN), and a wastewater treatment plant (WWTP), responsible for receiving and treating domestic residual effluents. Genotyping and the 16S rRNA gene sequence analysis demonstrated a higher diversity of species both in the WTP (6 species/19 isolates) and WWTP (12 species/47 isolates) than in the WDN (6 species/172 isolates). Staphylococcus pasteuri and Staphylococcus epidermidis prevailed in the WTP and WDN and Staphylococcus saprophyticus in the WWTP. Staphylococci with reduced susceptibility (resistance or intermediary phenotype) to beta-lactams, tetracycline, clindamycin and erythromycin were observed in all types of water and belonged to the three major species groups. The highest resistance rate was found against erythromycin, presumably due to the presence of the efflux pump encoded by the determinant msrA, detected in the majority of the resistant isolates. This study demonstrates that antibiotic resistant CNS may colonize different types of water, namely drinking water fulfilling all the quality standards.     

Prevalence of antibiotic and heavy metal resistance in Gram negative bacteria isolated from rivers in northern Pakistan

Antibiotic and metal resistance is a global occurring phenomenon and a universal threat. The release of antibiotics and metals into the environment like natural water bodies stimulates resistant microbes that could become a reservoir for a resistant gene pool for other pathogenic bacteria. The aim of the study was to determine microbial diversity, distribution of antibiotic and metal resistance bacteria from five rivers. The resistance of 168 Gram negative isolates was tested against 10 antibiotics and five metals. The study revealed a high incidence of bacterial isolates resistant to ampicillin (44.7%), streptomycin (37.3%) and chloramphenicol (33.9%). The highest level of antibiotic resistance was detected in the River Ravi. The multiple antibiotic resistance (MAR) index of the five rivers ranged from <0.2 to 0.6. Isolates displayed tolerance to different concentrations of heavy metals. High antibiotic and metal‐resistances in samples from the Rivers Ravi and Soan suggest co‐resistance amongst the bacterial populations.     

Behaviour in a river and dam of coliform bacteria with transferable or non-transferable drug resistance

The water in a river and the dam into which it flows was assayed for total coliforms and coliforms with transferable (R⁺) or non-transferable (R^-) resistance to five antimicrobial drugs. The effluent of a sewage works is discharged into the river 10 km upstream of the dam. The ratio of resistant to total coliforms decreased between the sewage works and the dam, but increased between the influent and effluent of the dam. This ratio was higher in the dam effluent than in the river upstream of the sewage works. No difference was detected in the survival of drug-sensitive and known R⁺ and R^- strains in distilled water or saline, or in dialysis bags immersed in the river or dam. Selection of those R⁺ strains resistant to a wide spectrum of drugs occurred in the river and dam. Immersed dialysis bags containing donor and recipient strains were used to demonstrate R factor transfer in the waters concerned. Three out of ten R⁺ strains isolated from the effluent of the dam yielded positive results. These donors were resistant to a wide spectrum of drugs but all determinants were transmitted at a relatively low frequency in the water. One donor had a higher frequency of transfer at 20 than at 37°C. The water pollution significance of these findings is discussed.     

Water quality control in the river Arno

In this work, we analyzed pollution in the river Arno using a non-steady advection-dispersion-reaction equation (ADRE) calibrated on experimental data. We examined the influence different pollution control strategies have on dissolved oxygen (DO). We considered (i) flow rate variation; (ii) local oxygenation at critical points; (iii) dynamic modification of wastewater load. Results indicate first, that reservoir management is effective in reducing pollution; second, that local oxygenation is necessary to ensure that DO does not fall below safety levels; and finally, that tuning wastewater loads appears to be impractical to manage the river quality given the stringent limitations it would impose on the industrial effluents.     

Measurement of protein-like fluorescence in river and waste water using a handheld spectrophotometer

Protein-like fluorescence intensity in rivers increases with increasing anthropogenic DOM inputs from sewerage and farm wastes. Here, a portable luminescence spectrophotometer was used to investigate if this technology could be used to provide both field scientists with a rapid pollution monitoring tool and process control engineers with a portable waste water monitoring device, through the measurement of river and waste water tryptophan-like fluorescence from a range of rivers in NE England and from effluents from within two waste water treatment plants. The portable spectrophotometer determined that waste waters and sewerage effluents had the highest tryptophan-like fluorescence intensity, urban streams had an intermediate tryptophan-like fluorescence intensity, and the upstream river samples of good water quality the lowest tryptophan-like fluorescence intensity. Replicate samples demonstrated that fluorescence intensity is reproducible to +/- 20% for low fluorescence, 'clean' river water samples and +/- 5% for urban water and waste waters. Correlations between fluorescence measured by the portable spectrophotometer with a conventional bench machine were 0.91; (Spearman's rho, n = 143), demonstrating that the portable spectrophotometer does correlate with tryptophan-like fluorescence intensity measured using the bench spectrophotometer.     

Contributions of genotoxic precursors from tributary rivers and sewage effluents to the Yodo River in Japan

The cause of water pollution in the Yodo River was examined regarding the mutagenic potentials formed by chlorination of river waters and sewage effluents along the river. Mutagenicity of the extracts from chlorinated waters was measured by Ames test using S. typhimurium TA100 strain without metabolic activation. Mutagenic formation potentials of sewage effluents were 4-5 times higher than those of the three tributary river waters, the Kizu, Uji and Katsura Rivers. The contribution rates of the pollution loads from the three river waters and total of four sewage effluents to the Yodo River were revealed to be 10.2%, 42.2%, 22.1% and 25.5%, respectively. The rate of the sewage effluents occupied one-fourth and exceeded the rates of the Kizu and Katsura Rivers. The contribution rate of the two sewage effluents to the Katsura River was 46.3%. It could be confirmed that the relationship between COD and MFP in river waters and sewage effluents was very high with a correlation coefficient. These results indicated that the waters inflowing to the Yodo River were contaminated with numerous organic compounds, and the sewage effluents especially contribute to the formation of genotoxicity by the interaction between chlorine and organic components as genotoxic precursors in the purification plants.     

Antibiotic resistant enterococci and staphylococci isolated from flies collected near confined poultry feeding operations

Use of antibiotics as feed additives in poultry production has been linked to the presence of antibiotic resistant bacteria in farm workers, consumer poultry products and the environs of confined poultry operations. There are concerns that these resistant bacteria may be transferred to communities near these operations; however, environmental pathways of exposure are not well documented. We assessed the prevalence of antibiotic resistant enterococci and staphylococci in stored poultry litter and flies collected near broiler chicken houses. Drug resistant enterococci and staphylococci were isolated from flies caught near confined poultry feeding operations in the summer of 2006. Susceptibility testing was conducted on isolates using antibiotics selected on the basis of their importance to human medicine and use in poultry production. Resistant isolates were then screened for genetic determinants of antibiotic resistance. A total of 142 enterococcal isolates and 144 staphylococcal isolates from both fly and poultry litter samples were identified. Resistance genes erm(B), erm(A), msr(C), msr(A/B) and mobile genetic elements associated with the conjugative transposon Tn916, were found in isolates recovered from both poultry litter and flies. Erm(B) was the most common resistance gene in enterococci, while erm(A) was the most common in staphylococci. We report that flies collected near broiler poultry operations may be involved in the spread of drug resistant bacteria from these operations and may increase the potential for human exposure to drug resistant bacteria.     

A proposal for managing wastewater in Harare, Zimbabwe

This paper deals with wastewater management in Harare, in the Lake Chivero catchment area of Zimbabwe. It aims at developing a sustainable system for managing water and nutrients and is based on the literature and a water quality monitoring study conducted from June 2000 to December 2001. This study has shown serious water pollution problems due to urbanisation in the catchment. A ‘three‐step strategic approach’ to urban (waste)water management was used as a basis for formulating solutions. The short‐term solutions include reduction of wastewater volume in industries and households, reducing wastewater flows by 24% and total phosphorus by 5%. The medium‐term solutions involve treating wastewater to high standards, resource recovery and reuse, and controlling upstream sources of pollution, and thus would reduce the lake total nitrogen and total phosphorus levels to about 0.4 and 0.07 mg/L, respectively. A long‐term solution was suggested based on pollution prevention and direct reuse, treatment at onsite and decentralised levels followed by reuse, and minimal disposal of the remaining effluents combined with the stimulation of the self‐purification capacity of the receiving rivers. It was concluded that it is feasible to reduce pollution levels in the catchment by applying these phased developments.     

Antibiotic resistance in bacteria from shrimp farming in mangrove areas

Shrimp farming is a sufficiently large and mature industry to have an effective range of antimicrobial agents for most bacterial diseases in shrimp culture. However, at present, there exists great concern over the widespread use of antibiotics in aquaculture, which may result in residue of antibiotics in water and mud, and subsequently, the development of antibiotic resistance in bacteria in the environment. There is limited understanding about the effect of antibiotic residues on bacteria resistance in shrimp farming environment. Therefore, a study was conducted to investigate bacterial resistance to Norfloxacin (NFXC), Oxolinic Acid (OXLA), Trimethoprim (TMP) and Sulfamethoxazole (SMX), which were found in four shrimp farming locations in mangrove areas in Vietnam. Findings indicate that there is a relatively high incidence of bacteria resistance to these antibiotics observed in most of the studied sites, particularly to antibiotics with concentration of 0.1 microg/ml. Yet the relation between concentration of antibiotic residues and incidence of antibiotic resistance is not clearly defined. Among individual antibiotics, the incidence of resistance to TMP and SMX was higher than the others. Identification of bacteria isolated from mud samples by DNA analyzer shows that Bacillus and Vibrio are predominant among bacteria resistant to the antibiotics. The result of the study also indicates that these antibiotics in media degraded more rapidly due to the presence of resistant bacteria.     

Pollution pattern surveillance on a river used as a drinking water source: The river meuse

The total amount of water to be abstracted by 1985 directly or indirectly from the river Meuse in Belgium and the Netherlands for water supply purposes, is estimated at 800 million m³. This prospect makes preservation of river water quality of the utmost importance. A detailed water quality surveillance system, covering the Belgian part of the Meuse river basin, was worked out in the early sixties by the water supply company of Antwerp.

The present state of the surveillance system is described. General features of the water pollution pattern in the river are discussed, with emphasis on pollution by heat, suspended solids, organic substance and salts.     

Technoeconomic Indicators Pertinent to Environmental Management in Metal Forging Industry

Effluents from metal forging industry are characterized by significant concentrations of heavy metals and cyanides which normally exceed allowable discharge limits. Pickling and electroplating processes are considered the principal generators of hazardous waste in this industry. This paper addresses development of upgraded environmental management practices in a metal forging plant located south of Cairo with the aim to establish an adequate pollution control system. Current pollution loads have been assessed with respect to quantity and characteristics. Optional environmental management systems have been proposed and compared, based on treatability studies and relevant technoeconomic grounds. The selected scheme encompassed chemical precipitation using lime for the treatment of pickling effluents. Zinc electroplating effluents are proposed to be treated through alkaline chlorination. Drying ponds are the proposed solution for the drying of sludges. The estimated average treatment cost for the combined flows is about L.E. 0.72/m 3 .     

Antimicrobial resistance and species composition of Enterococcus spp. isolated from waters and sands of marine recreational beaches in Southeastern Brazil

Density, species composition and antimicrobial resistance in bacteria of the Enterococcus genus were evaluated in seawater and sands from 2 marine recreational beaches with different levels of pollution. The 2 beaches showed predominance of Enterococcus faecalis and Enterococcus faecium, in the water and the sand. Dry sand presented higher densities of Enterococcus sp. and higher frequency of resistant strains than wet sand and seawater. The beach with a higher degree of pollution presented higher percentages of resistant strains (66.7% and 61.5%, in sand and in water, respectively) and resistance to a larger number of antimicrobials compared with the less polluted beach, Ilha Porchat (35.7% and 31.25% of resistant strains in sand and water, respectively). In water samples, the highest frequencies of resistance were obtained against streptomycin (38.5%) and erythromycin (25%), whilst in sand, the highest frequencies were observed in relation to erythromycin and tetracycline (38.1% and 14.3%, respectively). These results show that water and sands from beaches with high indexes of faecal contamination of human origin may be potential sources of contamination by pathogens and contribute to the dissemination of bacterial resistance.     

Resistance transfer fecal coliforms isolated from the whippany river

Three sites on the Whippany River, a tributary of the Passaic Watershed in Morris County, N.J., were monitored for resistance transfer coliforms. A high percentage of fecal coliform isolates showed multiple antibiotic resistance. A significant number of lac⁻ and lac⁻ isolates proved to be donors of transmissible antibiotic resistance plasmids (R donors), by conjugation with a recipient strain of Salmonella gallinarum. Re-examination of testing methods used for recreational and potable water sources is suggested by these findings.     

TREATMENT OF WASHWATER FROM SERVICE-RESERVOIR CLEANING IN HONG KONG

As a result of increasing control of environmental pollution in Hong Kong. the practice of discharging untreated service-reservoir washwater to the nearest watercourse is no longer permitted. This paper describes the results of field tests on alternative methods of treating the effluents produced from cleaning fresh-water and sea-water service reservoirs in Hong Kong, including trials of alternative cleaning procedures using high-pressure jetting which were designed to (a) upgrade the cleaning efficiency and (b) reduce the resulting pollution load. The results of effluent treatment, based on pilot-plant trials incorporating various combinations of filtration and centrifugation, are presented. The option which was selected for full-scale implementation, based on a mobile centrifugation and microfiltration unit, using a membrane developed in China specifically for the water industry, is described     

重庆市跳磴河流域水污染综合治理工程规划

采用流域分析方法，系统分析了重庆市跳磴河流域内影响生态环境质量的城镇污水、垃圾、工业排污、农业生产、水土流失、畜禽养殖、河流内源污染等问题，以环境容量和污染物总量控制为主线，提出了实现规划水质目标和生态环境质量目标的污染控制措施和生态建设内容，为类似流域的水污染综合治理工程的规划和设计提供参考。     

Study of heavy metal pollution and speciation in Buyak Menderes and Gediz river sediments

In this study, two economically important rivers of Turkey, Gediz and Buyuk Menderes (BM) are studied to determine their environmental pollution levels. An old analytical procedure involving sequential chemical extraction is improved and used for the partitioning of particulate trace metals (Cu, Co, Cr, Mn, Fe, Zn, Pb and Ni). Cationic and anionic Mn and Cr species with different phases are also determined by using leaching, extraction and ion exchange speciation processes.The sediment samples are analysed using graphic-furnace atomic absorption spectroscopy and differential pulse anodic stripping voltameter. Experimental results obtained on five replicate samples of fluvial bottom surface sediments at the sampling points demonstrate that the relative standard deviation of the sequential extraction procedure is generally better than +/-10%. The accuracy, determined by comparing total metal concentrations with the sum of the five sequential chemical extractions, is proved to be satisfactory. The detection limits established for three standard deviations of blank for different metals are identical and found to be 0.1mg/kg for sediment samples and 1 ppb for water samples. The results show that the pollution levels are significant especially for Pb, Cr, Mn and Zn in the Gediz river and Co, Mn, and Zn in the BM river. Comparison between our results and the measurements outlined before industrialization and the beginning of the intensive pesticide applications in agricultural fields (In: Broekaert et al., editors, Metal speciation in the environment, vol. 23. 1989. p. 601-11; A research on the environmental pollution in the agricultural fields and watering in the Aegean region, Ege University Research Project, No. 127 1988 (in Turkish); DSI Water Analyses Report, Ankara, 1985 (in Turkish)) show that the pollution in these rivers is probably originated from industrial, agricultural and domestic waste discharges.     

Escherichia coli contamination of the river Thames in different seasons and weather conditions

Contamination of public water ways with sewage represents a serious environmental and health risk. We monitored pollution of the river Thames by enumerating the indicator organism Escherichia coli. Samples were taken from a site in central London near Waterloo Bridge in different seasons. E. coli were quantified using a membrane filtration method, and correlated with the tidal variations of the river and meteorological data on rainfall and temperature. More frequent and severe incidents of pollution occurred in the autumn. Heavy rainfall resulted in sharp peaks of E. coli contamination that implies a potential increase of numbers of pathogenic micro‐organisms. Sixty percent of all samples were found to be in excess of the accepted upper limit of pollution set by European Union (EU) legislation for bathing water. This study demonstrated that frequent sewage pollution of the Thames results in high numbers of E. coli and incidents of detectable levels of pathogenic bacteria demonstrating the need for regular monitoring of bacterial pollution.     

巢湖市双桥河流域初期雨水污染控制技术

初期雨水污染是制约水环境质量的关键因素之一。监测数据显示,双桥河流域水环境质量呈现日益恶化的趋势,而初期雨水占污染排放总量的31.3%~50.0%。在对巢湖市双桥河区域排水系统及雨天溢流污染现状调查的基础上,提出了具体的工程方案,即新建调蓄干管和调蓄池。首先从工程建设、运行维护、环境效益和生态景观等多方面对方案进行比选;其次通过计算机模型分析对比多点分散式截流和末端截流2种不同截流方式的初期雨水污染物收集效率。结果显示,利用现状箱涵,新建2根初期雨水调蓄干管,不仅能取得较好的环境、经济和社会效益,而且对于初期雨水的收集效率也很高。