Total Suspended Research Articles

Wastewater Reclamation for Agricultural Reuse in Israel: Trends and Experimental Results

Water shortage and a deterioration in the quality of water resources in Israel have made necessary a national policy recommending reuse of practically all municipal wastewater in order to supply a major part of agricultural water demand. Two pilot-scale systems were operated and studied for several years. The first one consisted of an advanced treatment scheme incorporating a sequencing batch reactor (SBR) system with further deep-bed granular filtration. The second system was an SBR unit, for the purpose of optimizing nitrogen and phosphorus removal and testing further microfiltration of SBR effluents. The SBR process has been shown to be an efficient biological treatment method producing low Biochemical Oxygen Demand (BOD) and Total Suspended Solids (TSS) effluents. SBR effluents, even if loaded with high TSS concentrations, could be further purified in the filtration stage, producing low-turbidity effluents. Granular filtration experiments were carried out using a gravitational single-medium filter composed of uniformly-sieved quartz sand. It was found that most of the suspended solids were removed in the top 10 cm of the filter bed. Influent turbidity was found to be the main parameter affecting the process, while filtration rate had only a minor effect. Microfiltration of SBR effluents showed highly efficient removal of turbidity and pathogens. Advanced mathematical models were developed and calibrated for both the biological process and for the granular filtration process.

Artificial Wetland Performances in the Purification Efficiency of Hydrocarbon Wastewater

An artificial wetland planted with Typha latifolia was fed during a 360-day experiment with a reconstituted hydrocarbon wastewater (60 ppm, 850 L day−1). Concentrations and chemical composition were periodically monitored. The epuration efficiency was studied together with the accumulation in sediment and the bacterial development. The apparent effluent concentration was below 8 mg L−1 and the decrease in hydrocarbon concentration raised 90%. pH ranged between 6.9 and 8 and Total Suspended Solids (TSS) were below 10 mg L−1. Hydrocarbon amount accumulated in sediment was estimated to be less than 10% of the input amount. We observed a high development of aerobic heterotrophic bacteria (106 bac mL−1) and hydrocarbon-utilizing bacteria (105 bac mL−1), which probably interacted with the plants for the biodegradation of hydrocarbon (in the saturated effluent fraction, normal alkane biodegradation amounted to approximatively 80%). A comparative system with floating plants (Lemma minor), named ‘control bed’, was studied in parellel and showed lower performances.

Mutagenicity assessment of airborne particles in Mexico City

The Ames's TA98 strain of Salmonella typhimurium with and without mammalian metabolic activation was used to detect the mutagenic activity of organic chemicals associated with airborne particles. Two kinds of particles: total suspended (TSP) and those particles with an aerodynamic diameter of 10 μm or smaller (PM 10) were collected in glass fiber filters using high-volume samplers during the dry season (December 1989–March 1990) in the Metropolitan Area of Mexico City at five stations of the air quality network belonging to the Ministry of Social Development. Although the highest mass concentrations of particles were obtained from the Northeastern and Southeastern areas, the largest frequency of mutations was found Downtown which indicated that vehicle exhaust was an important source. Contrary to what was expected, the mutagenic responses were higher for PM10 than for TSP samples. On the other hand, the microsome activation increased significantly the mutagenic activity of the complex mixture, which hinted at the presence of higher amounts of indirect (or promutagens) than direct mutagens both for TSP and PM10.

Application of the UASB technology for sewage treatment in a small community at sumare, sao Paulo state

Sumare City does not have sewage treatment, leading to the deterioration of water resources and public health conditions. There is a sewage treatment plan for the city's urbanized area. However, difficulties of financing delay the plan's implementation. Meanwhile, new small communities of low income population are built surrounding the city. That was not foreseen in the city's plan. So, the sanitation problem is constantly aggravated. The city's Water and Wastewater Department (Departamento de A'guas e Esgotos - DAE), worried by this situation tried out a new scheme to overcome this problem. One of these communities (235 houses) was chosen and a proposal was made to its inhabitants, which was accepted, to use an anaerobic digester to treat the sewage, DAE being the financer agent and the inhabitants reimbursing DAE. The UASB technology was made available by means of an agreement between DAE-Sumare and CETESB for technology transfer. DAE was responsible for the management and plant construction. The plant was started-up in May 1992. This is a successful experience in view of the non-existence of finance for the construction of sewage systems. A 67.5 m3 UASB reactor was built. The difficulties to establish the real costs for this were extremely high, and lead to cost reduction recommendation. Data collected for performance evaluation, over a period of fourteen months showed a difference compared to the 120 m3 UASB reactor experience, at CETESB, in Sao Paulo City. The influent and effluent Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD) and Total Suspended Solids (TSS) values, are higher than were experienced at CETESB. The average removal rates of BOD, COD and TSS are also higher, respectively 80%, 74% and 87%.

Lead, titanium and zinc in air particulate at Dhahran, Saudi Arabia, during and after Kuwait oil fires

The 1991 Gulf Crisis had the potential to enhance atmospheric metal concentrations and this study was designed to investigate this probability. Total suspended (TSP) and inhalable (PM10) particulate were collected and analyzed for lead, titanium and zinc which were determined in aliquot samples using an inductively coupled argon plasma analyzer (ICAP). Significant ( P < 0.01) daily variations were found for lead, titanium and zinc concentrations (expressed as ng m −3) in air particulate. Concentrations of lead in the TSP samples were higher than in the inhalable fraction (PM10). The maximum mean concentration of lead was found in TSP samples collected during June 1991, which gradually decreased through December 1991, and spiked again during June 1992. The distributions in zinc and titanium in the air particulate samples were similar to that of lead. Lack of statistically significant differences in lead, titanium and zinc concentrations between 1991 and 1992 suggest limited inputs of these metals from the Kuwait oil fires, to the air particulate in Dhahran. A yearly mean of 282 ± 144 ng of lead m −3 air was calculated from the data for inhalable particulate collected in Dhahran. Lead poisoning is a chronic problem and automobile emissions may constitute a significant source of lead in air particulate in the Gulf region. Further monitoring of children, especially in the cities, for lead contamination is recommended.

Nickel and vanadium in air particulates at Dhahran (Saudi Arabia) during and after the Kuwait oil fires

Abstract Air particulates, both the total suspended (TSP) and inhalable (PM 10 , smaller than 10 microns in size), were collected during and after the Kuwait oil fires (from March 1991 to July 1992) using Hi-Vol samplers. These samples were wet-digested at 120°C in an aqua regia and perchloric acids mixture for 3 h. Air particulate samples collected in 1982 at the same location were prepared similarly. Concentrations of nickel and vanadium were determined in the aliquot samples using an inductively coupled argon plasma analyser (ICAP). The monthly mean concentrations of nickel and vanadium, on volume basis, increased rapidly from March to June and decreased sharply during July–August in 1991. The minimum mean concentrations of these elements were found in the particulate samples collected in December 1991 which gradually increased through May 1992. Like 1991, nickel and vanadium concentrations in the air particulates spiked in June and decreased again in July 1992. This distribution pattern of nickel and vanadium concentrations was similar to that of the predominant wind from the north (Kuwait). In general, concentrations of these elements were higher in the air particulates collected during April–July 1991 as compared with those collected in 1992 during the same period. The TSPs contained higher concentrations of nickel and vanadium than those found in the PM 10 samples. However, this trend was reversed when concentrations of nickel and vanadium, on were expressed on particulate weight basis. The monthly mean concentrations of nickel and vanadium, on weight basis, decreased gradually through 1991 and increased slightly from March to July 1992. Concentrations of these elements were significantly higher in the air particulate samples collected in 1991 than those samples collected during 1982 at the same location. The data of this study suggest a contribution of the Kuwait oil fires in elevating nickel and vanadium concentrations in the air particulates at Dhahran during April–July 1991. Concentrations of these elements were largely below their proposed limits in the ambient air (for nickel-50 μg m −3 , air; for vanadium—1 μg m −3 air). It is, therefore, anticipated that concentrations of nickel and vanadium in the air particulate samples were not a health concern during Kuwait oil fires at Dhahran, Saudi Arabia.

Availability of micronutrients during anaerobic digestion of molasses stellage using an Upflow Anaerobic Sludge Blanket (UASB) reactor.

Abstract During treatment of molasses stillage with an UASB reactor, the essential micronutrients such as Ni2+, Zn2+ and Cu2+ were removed from the UASB sludge matrix due to high concentration of K+ in the influent. The metal analysis of the sludge matrix showed a complete absence of Mo2+ and Co2+. Among the metals analysed in the seeding sludge, Zn (2.08 μg g‐1 Total Suspended Solids, TSS), Ni (625 μg g‐1 TSS) and Cu (2.08 μg g‐1 TSS) were found in low concentration as exchangeable form, when compared to Ca, Fe, Na, and K. It is presumed that presence of K (2.28 g 1‐1) in the 40% diluted molasses stillage is responsible for removal of exchangeable form of micronutrients from the sludge matrix. In summary, it is necessary to add micronutrients to the UASB reactor during anaerobic treatment of K enriched molasses stillage.

The use of coagulating and polymeric flocculating agents in the treatment of palm oil mill effluent (POME)

The reduction of pollution strength in palm oil mill effluent (POME) using five inorganic salts and nine polymers was investigated. Treatment of POME with 80–100 mg litre −1 of Magnafloc LT22 polymer aided in coagulation and flocculation of Total Suspended Solids, producing 96%, 63%, 53% and 93–94% reduction in the turbidity, chemical oxygen demand (COD), Total Solids (TS) and Total Suspended Solids (TSS) respectively, of the effluent. Treatment with 200 to 300 mg litre −1 FeCl 3 + 70 to 100 mg litre −1 Magnafloc LT22 polymer reduced COD, TS and TSS by 47 to 53%, 43 to 49% and 92 to 94%, respectively. The TSS of POME can be substantially reduced by treating with coagulating and flocculating agents before discharging into other treatment systems.

Erratum: “ Total Suspended Solids in Highway Runoff in Washington State ” by Randy Asplund, Brian W. Mar and John F. Ferguson (April, 1982)

Erratum: “ <i>Total Suspended Solids in Highway Runoff in Washington State</i> ” by Randy Asplund, Brian W. Mar and John F. Ferguson (April, 1982)