Characterisation and biological treatment of greywater.

Characterisation of greywater was conducted in two different greywater streams in the Netherlands (Groningen and Sneek). The concentrations of macropollutants and nutrients measured were very different in both streams; in particular the COD was 425 mg/L in Groningen's water whereas in Sneek it was 1,583 mg/L. The aerobic treatment of greywater in a fed-batch reactor led to a 90% removal of COD at different organic loading rates. Anaerobically, the removal reached 40% COD removal on average, the possible reason being the high amount of surfactants present in the influent.     

Effect of hot acid hydrolysis and hot chlorine dioxide stage on bleaching effluent biodegradability.

The hot acid hydrolysis followed by chlorine dioxide (A/D*) and hot chlorine dioxide (D*) technologies have proven very useful for bleaching of eucalyptus kraft pulp. Although the characteristics and biodegradability of effluents from conventional chlorine dioxide bleaching are well known, such information is not yet available for effluents derived from hot acid hydrolysis and hot chorine dioxide bleaching. This study discusses the characteristics and biodegradability of such effluents. Combined whole effluents from the complete sequences DEpD, D*EpD, A/D*EpD and ADEpD, and from the pre-bleaching sequences DEp, D*Ep, A/D*Ep and ADEp were characterized by quantifying their colour, AOX and organic load (BOD, COD, TOC). These effluents were also evaluated for their treatability by simulation of an activated sludge system. It was concluded that treatment in the laboratory sequencing batch reactor was efficient for removal of COD, BOD and TOC of all effluents. However, colour increased after biological treatment, with the greatest increase found for the effluent produced using the AD technology. Biological treatment was less efficient at removing AOX of effluents from the sequences with D*, A/D* and AD as the first stages, when compared to the reference D stage; there was evidence of the lower treatability of these organochlorine compounds from these sequences.     

Particle size distribution and property of bacteria attached to carbon fines in drinking water treatment

The quantitative change and size distribution of particles in the effluents from a sand filter and a granular activated carbon （GAC） filter in a drinking water treatment plant were investigated. The average total concentration of particles in the sand filter effluent during a filter cycle was 148 particles/mL, 27 of which were larger than 2 μm in size. The concentration in the GAC effluent （561 particles/mL） was significantly greater than that in the sand filter effluent. The concentration of particles larger than 2 μm in the GAC filter effluent reached 201 particles/mL, with the amount of particles with sizes between 2 μm and 15 μm increasing. The most probable number （MPN） of carbon fines reached 43 unit/L after six hours and fines between 0.45 μm and 8.0 μm accounted for more than 50%. The total concentration of outflowing bacteria in the GAC filter effluent, 350 CFU （colony-forming units） /mL, was greater than that in the sand filter effluent, 210 CFU/mL. The desorbed bacteria concentration reached an average of 310 CFU/mg fines. The disinfection efficiency of desorbed bacteria was lower than 40% with 1.5 mg/L of chlorine. The disinfection effect showed that the inactivation rate with 2.0 mg/L of chloramine （90%） was higher than that with chlorine （70%）. Experimental results indicated that the high particle concentration in raw water and sedimentation effluent led to high levels of outflowing particles in the sand filter effluent. The activated carbon fines in the effluent accounted for a small proportion of the total particle amount, but the existing bacteria attached to carbon fines may influence the drinking water safety. The disinfection efficiency of desorbed bacteria was lower than that of free bacteria with chlorine, and the disinfection effect on bacteria attached to carbon fines with chloramine was better than that with only chlorine.     

Evidence for a Reduction of 2,3,7,8-TCDD Toxic Equivalent Concentrations in White Sucker (Catostomus commersoni) Exposed to Bleached Kraft Pulp Mill Effluent,Following Process and Treatment Improvements

Over a 4-year period from 1990 to 1993, the H4IIE bioassay was used to measure 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalent concentrations (TECs) in the liver tissue of white sucker exposed to bleached kraft mill effluent. During two of the sampling periods, the H4IIE bioassay-derived TECs (BD-TECs) were compared directly with BD-TECs measured by a similar bioassay using a rainbow trout liver cell line (RTL-W1). From 1989 to 1993, chemistry-derived TECs (CD-TECs) were calculated directly from measured polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) concentrations in liver tissue. Chemistry-derived TECs were compared to bioassay-derived TECs using toxic equivalent factors (TEFs) developed for these systems. During the study period, the pulp mill began secondary treatment of effluent and increased the substitution of chlorine dioxide for molecular chlorine during bleaching. Significant reductions in H4IIE BD-TECs and CD-TECs were observed in liver tissue of both male and female white sucker during summer and fall sampling periods but not during spring sampling periods. Process and treatment improvements at this particular bleached kraft pulp mill appear to have been successful at reducing the levels of PCDDs and PCDFs found in white sucker exposed to the effluent. Despite the decreases in TECs, relative mixed function oxygenase (MFO) induction in the exposed white sucker did not decrease over the study period, suggesting the PCDDs and PCDFs are currently not the dominant MFO-inducing compounds in the effluent of this mill.     

On-site greywater treatment and reuse in multi-storey buildings.

The paper presents a study of a pilot plant treating light greywater for seven flats. The pilot plant combines biological treatment (RBC) with physicochemical treatment (sand filtration and disinfection). The pilot plant produced effluent of excellent quality, meeting the urban reuse quality regulations, and was very efficient in TSS turbidity and BOD removal: 82%, 98% and 96%, respectively. COD removal was somewhat lower (70-75%) indicating that the greywater may contain slowly-biodegradable organics. The RBC (attached growth biological system) was able to retain most of the solids as a result of bioflocculation; further it was proven to have very stable and reliable performance. Faecal coliforms and heterotrophic reductions were very high (100% and 99.99%, respectively) producing effluent that also met drinking water standards. The combination of low organic matter, nutrients and microbial indicators reduces the regrowth and fouling potentials in the reuse system, thus ensuring safe reuse of the treated greywater for toilet flushing.     

Potential of organic filter materials for treating greywater to achieve irrigation quality: a review

The objectives of this literature review were to: (i) evaluate the impact of greywater generated in rural communities, with the emphasis on Jordanian conditions, on soil, plant and public health and assess the need for treatment of this greywater before it is used for irrigation, and (ii) assess the potential of different types of organic by-products as carrier material in different filter units for removal of pollutants from greywater. Greywater with high BOD5, COD, high concentrations of SS, fat, oil and grease and high levels of surfactants is commonly found in rural areas in Jordan. Oxygen depletion, odour emission, hydrophobic soil phenomena, plant toxicity, blockage of piping systems and microbiological health risks are common problems associated with greywater without previous treatment. Organic by-products such as wood chips, bark, peat, wheat straw and corncob may be used as carrier material in so-called mulch filters for treating wastewater and greywater from different sources. A down-flow-mode vertical filter is a common setup used in mulch filters. Wastewaters with a wide range of SS, cBOD5 and COD fed into different mulch filters have been studied. The different mulch materials achieved SS removal ranging between 51 and 91%, a BOD5 reduction range of 55-99.9%, and COD removal of 51-98%. Most types of mulches achieved a higher organic matter removal than that achieved by an ordinary septic tank. Bark, peat and wood chips filters removed organic matter better than sand and trickling filters, under similar conditions. Release of filter material and increase in COD in the effluent was reported using some mulch materials. In conclusion, some mulch materials such as bark, peat and woodchips seem to have a great potential for treatment of greywater in robust, low-tech systems. They can be expected to be resilient in dealing with variable low and high organic loads and shock loads.     

合肥市滨湖新区塘西河再生水厂工程设计

本文介绍了合肥市塘西河再生水厂的工程设计参数、处理工艺流程及其设计特点。该工程污 水处理设计规模为3. 0万m3/d,处理工艺为预处理、AZ/0、膜生物反应池和二氧化氯消毒的一体化 联合工艺,污泥处理采用机械浓缩脱水一体机。水厂的出水水质要求同时满足《城镇污水处理厂污染 物排放标准》( GB 18918-2002)和《城市污水再生利用景观环境用水标准》( GB/T 18921-2002 )。全 厂区采用分散收集、生物和天然植物喷淋液的联合除臭技术。     

PhACs在城市污水中迁移机理的研究

以4种药理活性化合物(PhACs)为目标物,运用UPLC/MS为检测方法,针对其在城市污水处理厂工艺流程中的分布迁移进行了研究,并进一步实验研究了其迁移机理。所有PhACs在城市污水厂进出水中均被检出,进水中浓度为0.11μg/L(氯贝酸)-0.46μg/L(卡马西平),出水中50μg/L((氯贝酸)-0.45μg/L(卡马西平)。卡马西平几乎不能被去除,除此之外,在生物处理阶段可较有效去除其它PhACs,其迁移机理主要是生物降解,生物降解速率与化合物种类及污泥类型有关。     

Occurrence and reduction of pharmaceuticals in the water phase at Swedish wastewater treatment plants

During the last decade, several screening programs for pharmaceuticals at Swedish wastewater treatment plants (WWTPs) have been conducted by research institutes, county councils, and wastewater treatment companies. In this study, influent and effluent concentrations compiled from these screening programs were used to assess the occurrence and reduction of non-antibiotic pharmaceuticals for human usage. The study is limited to full-scale WWTPs with biological treatment. Based on the data compiled, a total of 70 non-antibiotic pharmaceuticals have been detected, at concentrations ranging from a few ng/L to several μg/L, in the influent water. The influent concentrations were compared with the sale volumes and for many pharmaceuticals it was shown that only a small fraction of the amount sold reaches WWTPs as dissolved parent compounds. Pharmaceuticals with low reduction degrees at traditional WWTPs were identified. Further comparison based on the biological treatment showed lower reduction degrees for several pharmaceuticals in trickling filter plants compared with activated sludge plants with nitrogen removal.     

Secondary effluent reclamation: combination of pre-treatment and disinfection technologies.

A study was carried out to evaluate the efficiency of secondary effluent additional treatment, using a combination of pre-treatments (ring filter, physico-chemical and infiltration-percolation) followed by disinfection methods (chlorine dioxide, peracetic acid and ultraviolet light). Three different indicator microorganisms were determined: E. coli, total coliforms and somatic bacteriophages. The results show better efficiency of physico-chemical and infiltration-percolation processes. Bacteriophages were eliminated to a lesser extent than bacterial indicators in all the treatment systems. Chlorine dioxide and peracetic acid seems to be more efficient in disinfection than ultraviolet light when a ring filter is the pre-treatment used. For the same doses and contact times, the efficiency of the disinfection methods is higher when the pre-treatment used is the physico-chemical or the infiltration-percolation system. The final effluent quality from the physico-chemical treatment train and the infiltration-percolation treatment train, followed by the disinfectants, achieves an E. coli content that allows the reuse in most of the uses described in the Spanish legislation for wastewater reuse.     

H_2O_2与沸石联用处理污水厂二级出水的研究

为探寻污水厂二级出水深度处理方法,以阜新市某污水处理公司二级出水为研究对象,进行H2O2与沸石联用去除水中COD、氨氮的研究。结果表明：在二氧化锰的催化作用下,pH值为7时,H2O2和沸石的投加量分别为1.5mL和2g,二级出水的COD从138.24mg/L降到52.76mg/L,去除率达到75.36%,NH3-N从20mg/L降到5mg/L,去除率为74.59%,出水有机物和氨氮含量达到国家相关出水标准。     

Correlations between surrogate nitrogenous organic precursors and C-, N-DBP formation

Nitrosamines have been emerging as disinfection byproducts in drinking water using source water impacted with domestic wastewaters. Nitrogenous organic compounds are suggested as precursors of nitrosamines, but many of them have not been identified. This study investigated the correlations between nine selected nitrogenous organic compounds with different characteristics and corresponding disinfection by-product formation potentials (nitrosamines, trihalomethanes (THMs), and haloacetic acids (HAAs)) from their reactions with free chlorine, chlorine dioxide and monochloramine. Besides dimethylamine, the well-known precursor of nitrosamines, 3-(N,N-dimethyloctylammonio)propanesulfonate (3-N,N-DAPSIS) inner salt and benzyldimethyltetradecylamine (benzalkonium chloride, BKC) were suggested as important nitrosamine precursors. 3-N,N-DAPSIS could form about 1,000 ng/L of N-nitrosodimethylamine (NDMA) and more than 1,000 μg/L of THMs. More than 150,000 ng/L of NDMA were observed when BKC was treated with monochloramine, and high levels of THMs (up to 2,700 μg/L) were also yielded. As expected, free chlorine produced higher levels of THMs and HAAs, and chlorine dioxide generated minor levels of traditional DBPs. Nitrosamines were mainly formed when the precursors were treated with monochloramine.     

Resources and nutrients oriented greywater treatment for non-potable reuses

This paper evaluated the performance and suitability of a resources and nutrients oriented decentralized greywater treatment system which uses a submerged spiral wound module. This greywater treatment system is aimed at treating and recovering the resources present in the wastewater. The study revealed that the UF membrane filtration system was able to maintain a permeate flux between 6 and 10 L/m2/h. TOC can be reduced from the influent value of 161 to 28.6 mg/L in the permeate, meaning an average elimination rate of 83.4%. In addition, soluble nutrients such as ammonia and phosphorus can pass through the UF membrane and remain in the permeate. The total nitrogen and total phosphorus in the permeate were 16.7 and 6.7 mg/L respectively. The permeate was low in turbidity (below 1 NTU) and free of suspended solids and E. coli and had an excellent physical appearance. The permeate can be used in gardening and agriculture for irrigation and soil fertilization or alternatively for toilet flushing after disinfection. The retentate generated in this system can be treated with blackwater and kitchen waste in an anaerobic digester at a later stage for producing biogas or compost.     

人工快速渗滤技术净化微污染水的试验研究

采用人工快速渗滤技术净化河道微污染水,渗滤柱内介质分别为不同厚度的火山岩、粗砂、铁矿砂和直径不等的砾石.粗砂滤柱出水水质NH3-N在0.05mg/L以下,TN在lmg/L以下,CODcr在(15～40)mg/L范围,TP在0.1 mg/L以下,叶绿素a在2mg/L以下;砾石滤柱出水水质NH3-N在0.05mg/以下,TN在1.5 mg/L以下,CODcr在35 mg/L左右,TP在0.1mg/L以下,叶绿素a在(1～5)mg/L范围.粗砂滤柱与砾石滤柱对微污染水的去除效率基本相同,但砾石滤柱渗透系数与粗砂滤柱相比.大了2个数量级.     

疫情下农村污水处理设施的风险控制及消毒措施

针对新型冠状病毒对农村小型污水处理设施造成的潜在健康风险,分析了农村常用的处理工艺,包括人工快渗、A/O活性污泥及生物膜法、厌氧生物处理联合人工湿地以及MBR法的杀菌效果及出水特点,并在目前适用的次氯酸钠、二氧化氯及紫外线3种消毒技术的基础上,提出了对应的消毒工艺、参数选择及相关风险防控措施,为疫情防控期间农村小型污水处理设施的安全运行提供参考。     

净水工艺中剑水蚤的二次繁殖及控制

为解决净水工艺中剑水蚤的二次繁殖问题,进行了生产性试验,考察了二氧化氯与常规工艺协同对剑水蚤的去除效果.指出滤池滞水区停留时间长、流速低是造成剑水蚤二次繁殖的主要原因.二氧化氯预氧化可以强化常规处理工艺对剑水蚤的去除,当二氧化氯投加量为2 mg/L时,可以有效控制剑水蚤的二次繁殖.     

Improving chlorine disinfection of wastewater by ultrasound application .

The presence of soluble organic material as well as high concentrations of suspended matter in waters and wastewaters affect the efficiency when chlorine is used as disinfection agent. The objective of our work is to explore to which extend ultrasonic treatment can facilitate wastewater disinfection with chlorine in order to bring down doses of ecologically questionable chlorine and to shorten contact times. Sewage treatment plant (STP) effluents with different concentrations of suspended solids are exposed to sonication in combination with chlorine dosage. We observed that enhancement of chlorine efficiency is better for samples with higher concentrations of suspended matter. For samples with a TSS concentration of 50 mg/L chlorination efficiency (2 mg/L) can be doubled from 0.7 to 1.4 log when treated simultaneously with 20 kHz ultrasound for 5 minutes, i.e. levels of indicator organisms can be brought down to numbers that conventionally require far higher doses of chemical disinfectants. As subsequent sonication/chlorination does not have the same significant effect as simultaneous application of these two means, ultrasound does not just have a declumping effect; it seems that ultrasound application provokes a better chlorine dispersion in the aqueous media which improves the fast chemical and bactericidal reaction.     

Effect of recirculation on organic matter removal in a hybrid constructed wetland system

This research project aimed to determine the technologically feasible and applicable wastewater treatment systems which will be constructed to solve environmental problems caused by small communities in Turkey. Pilot-scale treatment of a small community's wastewater was performed over a period of more than 2 years in order to show applicability of these systems. The present study involves removal of organic matter and suspended solids in serially operated horizontal (HFCW) and vertical (VFCW) sub-surface flow constructed wetlands. The pilot-scale wetland was constructed downstream of anaerobic reactors at the campus of TUBITAK-MRC. Anaerobically pretreated wastewater was introduced into this hybrid two-stage sub-surface flow wetland system (TSCW). Wastewater was first introduced into the horizontal sub-surface flow system and then the vertical flow system before being discharged. Recirculation of the effluent was tested in the system. When the recirculation ratio was 100%, average removal efficiencies for TSCW were 91 +/- 4% for COD, 83 +/- 10% for BOD and 96 +/- 3% for suspended solids with average effluent concentrations of 9 +/- 5 mg/L COD, 6 +/- 3 mg/L BOD and 1 mg/L for suspended solids. Comparing non-recirculation and recirculation periods, the lowest effluent concentrations were obtained with a 100% recirculation ratio. The effluent concentrations met the Turkish regulations for discharge limits of COD, BOD and TSS in each case. The study showed that a hybrid constructed wetland system with recirculation is a very effective method of obtaining very low effluent organic matter and suspended solids concentrations downstream of anaerobic pretreatment of domestic wastewaters in small communities.     

生活饮用水二氧化氯消毒副产物检测技术的研究与应用

建立生活饮用水中二氧化氯消毒副产物氯酸盐、亚氯酸盐及氟化物、氯化物、硝酸盐、硫酸盐等6种无机阴离子的同时测定方法。以离子色谱法为测试手段,对采用二氧化氯消毒的生活饮用水出厂水及管网水中氯酸盐、亚氯酸盐含量进行测定。结果:分析方法的线性相关系数在0.9990-0.9994之间,,测试值的相对标准偏差RSD为1.49%-4.12%,各组份的检出限在0.0050-0.0225mg/L之间,回收率为96.0%-102.0%。方法简单、快速、准确、灵敏,适于大批量水样分析。出厂水及末梢水中二氧化氯消毒产生的消毒副产物均符合国标。     

Disinfection by-products and microbial contamination in the treatment of pool water with granular activated carbon.

For swimming pools, it is generally agreed that free chlorine levels have to be maintained to guarantee adequate disinfection. Recommended free chlorine levels can vary between 0.3 and 0.6 mg/L in Germany and up to 3 mg/L in other countries. Bathers introduce considerable amounts of organic matter, mainly in the form of such as urine and sweat, into the pool water. As a consequence, disinfection byproducts (DBPs) are formed. Regulations in Germany recommend levels of combined chlorine of less than 0.2 mg/L and levels of trihalomethanes (THMs) of less than 20 microg/L. Haloacetic acids (HAAs), haloacetonitriles (HANs), chloropicrin and chloral hydrate are also detected in considerable amounts. However, these compounds are not regulated yet. Swimming pool staff and swimmers, especially athletes, are primarily exposed to these byproducts by inhalation and/or dermal uptake. In Germany, new regulations for swimming pool water treatment generally require the use of activated carbon. In this project, three different types of granular activated carbon (GAC) (one standard GAC, two catalytic GACs) are compared for their long time behaviour in pool water treatment. In a pilot plant operated with real swimming pool water, production and removal of disinfection byproducts (THMs, HAAs, AOXs), of biodegradable substances (AOC), of bacteria (Pseudomonas aeruginosa, Legionella, coliforms, HPC) as well as the removal of chlorine and chloramines are monitored as function of GAC bed depth. Combined chlorine penetrates deeper in the filter bed than free chlorine does. However, both, free and combined chlorine removal efficiencies decrease over the time of filter operation. The decreases of removal efficiencies are also observed for parameters such as dissolved organic carbon, spectral absorption coefficient, adsorbable organic carbon and most of the disinfection byproducts. However, THMs, especially chloroform are produced in the filter bed. The GAC beds were contaminated microbially, especially with P. aeruginosa. The contamination was not removable by backwashing with chlorine concentrations up to 2 mg/l free chlorine.