An integrated chemical–physical–biological treatment concept for the low-cost treatment of domestic wastewater is proposed. Domestic wastewater was subjected to a chemically enhanced primary ...treatment (CEPT), followed by treatment in an upflow anaerobic sludge blanket (UASB) reactor. In addition, a regenerable zeolite was used to remove NH
4
+, either after CEPT pretreatment or after biological treatment in the UASB reactor. The CEPT pretreatment consisted of the addition of a coagulant (FeCl
3) and an anionic organic flocculant and removed on average 73% of the total chemical oxygen demand (COD
t), 85% of the total suspended solids, and 80% of PO
4
3− present in the wastewater. The UASB system, which consequently received a low COD
t input of approximately 140
mg/L, was operated using a volumetric loading rate of 0.4
g COD
t/L. d (hydraulic retention time HRT=10
h) and 0.7
g COD
t/L. d (HRT=5
h). For these conditions, the system removed about 55% of the COD
t in its influent, thus producing an effluent with a low COD
t of approximately 50
mg/L. The zeolite, when applied in batch mode before the UASB reactor, removed approximately 45% of the NH
4
+, whereas its application as a post-treatment cartridge resulted in almost 100% NH
4
+ removal. The simple design and relatively low operating costs, due to low costs of added chemicals and low energy input (estimated at € 0.07–0.1 per m
3 wastewater treated), combined with excellent treatment performance, means that this system can be used as a novel domestic wastewater treatment system for developing countries. Therefore, the system is called a Low Investment Sewage Treatment (LIST) system.
The proclivity of
d-amphetamine and methylphenidate to induce perseverative motoric and vocal side effects detracts from the clinical efficacy of these stimulants in the treatment of ...Attention-Deficit Hyperactivity Disorder (ADHD). In an attempt to develop a model for these deleterious treatment effects, this study explored the behavioral influences exerted by
d-amphetamine and methylphenidate in the young laboratory rat. This experiment revealed that doses of these stimulants that typically induce stereotypy provoke diverging behavioral profiles: while animals given 5 mg/kg
d-amphetamine exhibited repetitive sniffing activity, rats treated with 30 mg/kg methyl-phenidate displayed perseverative gnawing behaviors. Although pretreatment with the serotonin synthesis inhibitor
p-chlorophenylalanine (PCPA) significantly attenuated both stimulant-induced stereotypies, the effect of PCPA on
d-amphetamine-induced sniffing was more profound than on methylphenidate-induced gnawing. High-performance liquid chromatography (HPLC) analysis of monoamine levels in the striatum, frontal cortex, and thalamus indicated that PCPA induced an overall 89% depletion of serotonin across all conditions. These findings shed some light on the neurochemical mechanisms that underlie the differential effects of
d-amphetamine and methylphenidate on stereotyped motor activity in the rat, and suggest future experiments for understanding the role of serotonin in such effects. Further, these results have implications for the differential side effects observed from each of these stimulants when used clinically in children with ADHD.
Two-phase (acid-gas) anaerobic digestion can improve process performance relative to conventional, mesophilic, single-phase anaerobic digestion. However, few studies have considered the impact of ...phase separation on microbial community structure. We compared six full-scale, two-phase digestion (TPD) facilities and four conventional digestion (CD) facilities at municipal wastewater treatment plants by collecting performance data and evaluating microbial community structure
via
Illumina 16S rRNA gene sequencing. Sequence data indicated that nearly complete phase separation was achieved in all TPDs with few syntrophic bacteria or methanogens detected in acid phase digesters (APDs). Thermophilic methane phase digesters (MPDs) exhibited poor performance relative to mesophilic MPDs consistent with substantially lower relative abundances of syntrophic bacteria and methanogens in thermophilic MPDs. Although known syntrophic acetate oxidizers were only detected at very low levels in MPDs (0.11 ± 0.20%), the low abundance of aceticlastic methanogens observed suggests that syntrophic acetate oxidation plays a prominent role by yet to be described populations in TPD. TPDs exhibited greater microbial diversity than CDs, likely due to APDs supporting more diverse populations of hydrolytic and fermentative bacteria.
Sequencing of full-scale, two-phase anaerobic digesters suggested that increased microbial community diversity improves process performance.
Microbial ecology and environmental biotechnology are blossoming fields that are taking advantage of profound advances in biology, materials, computing, and engineering. Although traditionally ...microbial ecology and environmental biotechnology have been distinct disciplines, their futures are intimately linked. Together, they offer much promise for helping society deal with some of its greatest challenges in environmental quality, sustainability, security, and human health.
An anaerobic sequencing batch reactor (ASBR), seeded with a biomass inoculum that previously had not been exposed to the macrolide antimicrobial tylosin (mixture of Tylosin A, B, C, and D), was ...operated for 3 months with swine waste without Tylosin A and for 9 months with swine waste containing Tylosin A at an average concentration of 1.6mg/L. When swine waste with tylosin was fed to the ASBR, methane production and volatile solids removal did not appear to be inhibited and a methane yield of 0.47L methane per gram volatile solids fed to the ASBR was observed. Throughout the operating period, Tylosin A levels in ASBR biomass and effluent were below the detection limit of 0.01mg/L. However, during the first 3 months of operation, the levels of macrolide–lincosamide–streptogramin B (MLSB)-resistant bacteria in the ASBR biomass increased substantially as determined by hybridizations with oligonucleotide probes designed to target MLSB-resistant bacteria. Since no Tylosin A was present in the swine waste during the initial 3 months, the presence of MLSB-resistant bacteria in the swine waste was likely the reason for the increase in resistance. Subsequently, the levels of MLSB-resistant bacteria in ASBR biomass stabilized with an average of 44.9% for the 9 months of operation with swine waste containing Tylosin A. The level of MLSB-resistant bacteria in the swine waste fed to the ASBR during this period averaged 18.0%. The results indicate that anaerobic treatment of a waste stream containing tylosin was effective (based on reactor performance) and that the level of resistant bacteria in the ASBR was substantially higher than in the waste stream fed to this system.
This study demonstrates the accumulation and degradation of trehalose as a storage compound in a glucose-fed anaerobic sequencing batch reactor (ASBR). One hour after substrate addition, only 40% of ...the added organic matter (as chemical oxygen demand, COD) was accounted for by the cumulative methane production and soluble COD remaining in the reactor. All influent COD was accounted for by methane and biomass production by the end of the 24-h ASBR cycle. These dynamics can be explained by the production of an intracellular storage product. Total carbohydrate analysis showed that 26% of the glucose added to the reactor transiently accumulated within the biomass. Based on
13C-nuclear magnetic resonance (NMR) analysis, trehalose (
α-
d-glucopyranosyl-(
d-glucopyranoside)) was identified as the main carbohydrate produced. Mathematical modeling was performed and the IWA Anaerobic Digestion Model No. 1 (ADM1) was modified to include microbial storage. The modified model adequately described the ASBR dynamics during a 24-h cycle.
Variable conditions on active construction sites make erosion and sediment control a necessity and a challenge. A large number
of non-structural products and materials are available to help prevent ...storm water runoff and control sediment movement to
streams. The objective of this study was to determine what materials were available in California, what materials were used
and how much of the most used products were applied to the soil. Data are from four mail surveys of Certified Erosion Control
Specialists, contractors, consultants, and product manufacturers. Response to the surveys was 15 percent from the contractors
and erosion control professionals and 23 percent from the manufacturers. From the surveys, we gathered data on 493 materials
used by 155 respondents. Wattles, logs and rolls were used by the largest percentage of respondents (83 percent), followed
by blankets (63 percent), mulch (56 percent), dust suppressants (36 percent), tackifiers (30 percent), soil drying agents
(18 percent), and soil binders (14 percent).
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