乙酸钠作为碳源不同污泥源短程反硝化过程亚硝酸盐积累特性

为探究乙酸钠作为碳源时,不同污泥源外源短程反硝化过程中亚硝酸盐积累特性,采用1号和2号SBR分别接种某污水处理厂二沉池和同步硝化反硝化除磷系统剩余污泥,通过合理控制初始硝酸盐浓度和缺氧时间,实现了短程反硝化的启动,并考察了其在不同初始COD和NO3--N浓度条件下的碳、氮去除特性。试验结果表明:以乙酸钠为碳源,1号和2号SBR可分别在21d和20d实现短程反硝化的成功启动,且其NO2--N积累量和亚硝酸盐积累率(NAR)均维持在较高水平,分别为12.61mg·L-1、79.76%和13.85mg·L-1、87.60%。当2号SBR初始NO3--N浓度为20mg·L-1,且初始COD浓度由60mg·L-1升高至140mg·L-1时,系统实现最高NO2--N积累时间可由160min逐渐缩短至6min,同时NO3--N比反硝化速率(以VSS计)由3.84mg·(g·h)-1增加至7.35mg·(g·h)-1,初始COD浓度的提高有利于实现短程反硝化过程NO2--N积累。2号SBR初始COD浓度为100mg·L-1,当初始NO3--N浓度由20mg·L-1增加至30mg·L-1时,系统NAR均维持在90%以上,最高可达100%(NO3--N初始浓度为25mg·L-1);当初始NO3--N浓度≥35mg·L-1时,系统COD不足导致NO3--N不能被完全还原为NO2--N。此外,在不同初始COD浓度(80、100、120mg·L-1)和NO3--N浓度(20、25、30、40mg·L-1)条件下,2号SBR的脱氮除碳和短程反硝化性能均优于1号SBR。     

基于不同废污泥源的短程反硝化快速启动及稳定性

为探究不同废污泥源快速启动短程反硝化和实现稳定NO_2~--N积累的可行性,在3个完全相同的SBR反应器(S1、S2和S3)分别接种:实验室城市污水反硝化除磷系统排泥、城市污水厂剩余污泥及河涌底泥,比较其短程反硝化启动快慢和NO_2~--N积累特性,考察系统短程反硝化活性和NO_3~--N→NO_2~--N转化性能,并从微生物学角度分析反应器功能菌群特征.结果表明,在乙酸钠为唯一碳源、高碱度和适宜COD/NO_3~--N比进水条件下,3个SBR短程反硝化反应器在短时间内均能够成功启动,系统平均NO_3~--N→NO_2~--N转化率为S1 S2 S3(75. 92% 73. 36% 69. 90%).同时发现持续低温条件下S1和S2呈现不同程度的短程反硝化性能恶化趋势,但S3能够稳定维持良好NO_2~--N积累性能.微生物高通量测序表明,变形菌门和拟杆菌门居PD系统主导地位,3个短程反硝化反应器NO_2~--N积累关键功能菌属Thauera属丰度差异明显:S3 S1 S2(25. 09% 4. 71% 3. 60%),表明S3具备稳定高效的NO_2~--N积累性能,同时高丰度Thauera属可能是维持低温短程反硝化活性的重要原因.     

低温SBR反硝化过程亚硝态氮积累试验研究

采用SBR法处理经缺氧/厌氧UASB预处理的渗滤液,在SBR反硝化过程观察到明显的亚硝态氮积累现象.在此基础上,为深入了解反硝化过程亚硝态氮积累的机制,考察低温条件下5种类型碳源(甲醇、乙醇、乙酸钠、丙酸钠和葡萄糖)对SBR反硝化过程亚硝态氮积累的影响.结果表明,在温度为13.9℃情况下,甲醇、乙醇、乙酸钠、丙酸钠为反硝化碳源时,系统内均发生明显的亚硝态氮积累.此外,4种不同初始NO_3~--N浓度(64.9、 54.8、 49.3、 29.5 mg/L)还原过程中, NO_2~--N最大积累浓度分别为37.8、 21.5、 25.2、 18.8 mg/L,积累速率(N/VSS·t)分别为 0.117、 0.136、 0.235、 0.068 g/(g·d),并且ORP曲线先后出现"nitrate knee"和"nitrite knee"2个拐点,可分别指示NO_3~--N、NO_2~--N还原反应结束.     

甲醇为碳源短程反硝化亚硝酸盐积累特性

接种反硝化过程中亚硝态氮(NO_2~--N)积累效果稳定的短程反硝化污泥,以甲醇为碳源,通过批次试验研究了不同碳氮比(C/N)、硝态氮(NO_3~--N)浓度及p H条件下短程反硝化过程中NO_2~--N积累特性.实验结果表明:当C/N为2.5时,NO_2~--N积累率最高为89%,且NO_2~--N不会被还原;当C/N为3~5时,NO_2~--N积累到最大值后开始降低,但NO_2~--N最大积累量和比反硝化速率没有明显差异.当NO_3~--N浓度在14.91~82.58mg/L范围内,NO_3~--N浓度越高,达到NO_2~--N最大积累率理论所需C/N越低.且当NO_3~--N浓度小于58.71mg/L时,比NO_3~--N还原速率、比NO_2~--N积累速率随NO_3~--N浓度增加而上升.当p H=7时,NO_2~--N积累量、比NO_3~--N还原速率和比NO_2~--N积累速率最高,分别为24.49mg/L、18.96(mg/(g VSS·h))、18.91(mg/(g VSS·h)),然后依次是p H=6、8、9.p H=5和10时,短程反硝化基本不能进行.本研究可以为短程反硝化的实现及应用提供理论依据.     

不同碳氮比下污水反硝化过程中亚硝氮积累的特性研究

以乙酸钠为碳源,在不同的碳氮比(COD/NO_3~--N)条件下,通过控制反应器中反硝化时间,将NO_3~--N仅还原至NO_2~--N,实现NO_2~--N的稳定积累.结果表明,反硝化时间从60 min缩短至20 min,NO_3~--N还原速率和NO_2~--N积累速率分别增大至0.417 g·g~(-1)·h~(-1)(以VSS计,下同)和0.402g·g~(-1)·h~(-1).经过108 d的培养,NO_2~--N的积累率为95%.反硝化活性随碳氮比的增大而增大,而较低碳氮比更有利于NO_2~--N的稳定积累.在反硝化亚硝氮积累过程中,当碳源充足时,由于电子受体NO_3~--N和NO_2~--N相互竞争碳源,NO_3~--N的存在会抑制NO_2~--N的还原,从而导致NO_2~--N积累;而当碳源不足时,基质限制使NO_3~--N优先还原,导致NO_2~--N的积累.微生物宏基因组测序结果表明,培养污泥中的优势菌群为Thauera(71.85%),该菌仅能将NO_3~--N还原为NO_2~--N,从而导致NO_2~--N的积累.     

硝酸盐对短程反硝化过程中亚硝酸盐积累影响

该文以乙酸钠为碳源,通过批次试验探究短程反硝化过程中硝酸盐对亚硝酸盐积累的影响。试验结果表明在不同的C/N比条件下,NO_2~--N均能出现积累,C/N较低(0.8～2.4)的情况下系统中出现NO_3~--N与NO_2~--N共存情况;当C/N为3.2～8.0时,随着反应进行NO_2~--N的量有所损耗,表明C/N比过高不利于NO_2~--N的积累;C/N比会影响NO_2~--N的积累速率,但对转化率影响不大。当起始系统中只有NO_3~--N时,NO_3~--N→NO_2~--N反应速率高于NO_2~--N→N_2的反应速率;随着初始NO_3~--N浓度(20～150 mg/L)增加,NO_2~--N积累速率加快。向只有NO_2~--N的反应系统中添加当NO_3~--N,一直被还原的NO_2~--N开始出现积累,表明系统中存在NO_3~--N时,对NO_2~--N→N_2发生可能存在抑制作用。初始系统中同时存在NO_3~--N和NO_2~--N时,NO_3~--N还原速率高于NO_2~--N的还原速率;当NO_3~--N消耗完全之后,NO_2~--N的还原速率高于血清瓶有NO_3~--N存在时的还原速率;随着NO_3~--N/NO_2~--N的比值的增加,NO_3~--N的还原速率和NO_2~--N的积累速率加大。该研究可为短程反硝化厌氧氨氧化耦合工艺处理含氮污水提供一定的理论依据。     

PD-DPR系统处理城市污水与高硝酸盐废水实现稳定亚硝酸盐积累和磷去除的特性

本研究以模拟城市污水和高硝酸盐废水为处理对象,在一个厌氧-缺氧-微曝气运行的SBR反应器内,将短程反硝化工艺(PD,NO_3~-→NO_2~--N)与反硝化除磷工艺(DPR)耦合,并通过联合调控进水C/N比、厌氧排水率和缺氧时间,考察了PD-DPR系统的亚硝酸盐积累特性和除磷性能.结果表明,经过140d,NO_3~-→NO_2~--N转化率(NTR)为80.1%,PO~(3-)_4-P去除率高达97.64%.在厌氧段(180 min),聚糖菌(GAOs)和聚磷菌(PAOs)对污水有机碳源进行充分利用,将其转化为内碳源;缺氧段(150 min),反硝化聚糖菌(DGAOs)和异养反硝化菌(DOHOs)分别进行内源和外源短程反硝化实现NO~-_2-N稳定积累,同时反硝化聚磷菌(DPAOs)进行高效反硝化吸磷;微曝气段(10 min),在不发生硝化反应的前提下,PAOs超量吸磷,提高了系统的除磷性能.系统出水NO~-_2-N/NH~+_4-N为1.31∶1(接近厌氧氨氧化工艺理论值1.32∶1),PO~(3-)_4-P浓度为0.30 mg·L~(-1),COD浓度为12.94 mg·L~(-1).其出水水质可满足与厌氧氨氧化(ANAMMOX)工艺耦合进行深度脱氮的需求.     

高氨氮废水短程硝化过程中N2O释放试验研究

试验采用序批式反应器(SBR)处理高氨氮废水,逐步提高废水氨氮(NH+4-N)浓度到800 mg·L-1,通过控制曝气量实现了短程硝化.SBR周期试验表明,在低溶解氧和高游离氨等共同作用下,氨氧化菌(AOB)活性较低,导致AOB以亚硝酸盐氮(NO_2~--N)作为电子受体进行好氧反硝化,氧化亚氮(N_2O)释放因子为9.8%.静态试验控制初始NH_4~+-N为100 mg·L-1且改变曝气量(0.22~0.88 L·min~(-1))条件下,溶解氧浓度的增加能够提高硝化菌活性,N2O释放因子为0.51%~0.85%.当初始NH_4~+-N浓度为100 mg·L~(-1)且曝气量控制在0.66 L·min-1时,初始NO-2-N浓度为0~100 mg·L~(-1)对硝化菌活性影响较小,N2O释放因子为0.50%~0.71%.当溶解氧和游离氨浓度控制在适宜范围内,可维持AOB较高活性,抑制AOB发生好氧反硝化作用,降低N2O释放率.     

Cu2+对以NO2-为电子受体反硝化过程的影响

短程生物脱氮工艺在废水处理中已经得到较为广泛的应用,其反硝化过程是实现氮去除的关键步骤,而关于废水中常见重金属离子Cu~(2+)对以NO2-为电子受体反硝化过程的影响尚无系统研究.选取A/O反应器内具有良好短程生物脱氮特性的污泥,通过批次试验及SBR长期试验分别探究了Cu~(2+)对以NO2-为电子受体反硝化过程的短期及长期影响.短期试验结果表明,Cu~(2+)对以NO2-为电子受体反硝化过程具有明显抑制作用,对污泥反硝化活性的半抑制浓度EC50为4. 79 mg·L-1.在长期影响试验中逐渐提高污泥对Cu~(2+)的耐受浓度,当Cu~(2+)浓度为0. 5 mg·L-1和1 mg·L-1时,污泥反硝化活性降低后均能够通过驯化恢复至原有水平;而Cu~(2+)浓度升高至3 mg·L-1后污泥反硝化性能遭到破坏且难以恢复,NO_2~--N去除率降低至10%以下,反硝化系统遭到严重抑制.但是,停止投加Cu~(2+)后污泥反硝化活性在第14 d恢复至原有水平.同时,在Cu~(2+)的长期影响过程中,EPS含量增多,对微生物抵御Cu~(2+)的毒害起到重要保护作用,促使污泥粒径增大,污泥沉降性得到提高.     

SBR短程脱氮系统中亚硝酸盐积累对生物除磷的影响

采用SBR工艺处理实际生活污水,通过控制好氧段的DO浓度及曝气时间,实现了短程硝化反硝化,并考察了短程硝化引起的亚硝酸盐积累对生物除磷系统的影响.结果表明,在没有补充外碳源的情况下,好氧阶段NO2--N的积累低于10 mg·L-1时,聚磷菌的吸磷及放磷能力没有受到影响,好氧出水磷浓度基本维持在1 mg·L-1以下;当N...     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.     

Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

ＲｅｍｏｖａｌｏｆｈｅａｖｙｍｅｔａｌｓｆｒｏｍｓｅｗａｇｅｓｌｕｄｇｅｂｙｌｏｗｃｏｓｔｉｎｇｃｈｅｍｉｃａｌｍｅｔｈｏｄａｎｄｒｅｃｙｃｌｉｎｇｉｎａｇｒｉｃｕｌｔｕｒｅＷｕＱｉｔａｎｇ，ＮｙｉｒａｎｄｅｇｅＰａｓｃａｓｉｅ，ＭｏＣｅｈｕｉＦ...     

Single and joint effects of pesticides and mercury on soil urease

The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase （up to 13%-21%） in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship （P〈0.05） between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose （ED50） values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.     

Isolation and preliminary characterization of a 3-chlorobenzoate degrading bacteria

A study was conducted to compare the diversity of 2-, 3-, and 4-chlorobenzoate degraders in two pristine soils and one contaminated sewage sludge. These samples contained strikingly different populations of mono-chlorobenzoate degraders. Although fewer cultures were isolated in the uncontaminated soils than contaminated one, the ability of microbial populations to mineralize chlorobenzoate was widespread. The 3- and 4-chlorobenzoate degraders were more diverse than the 2-chlorobenzoate degraders. One of the strains isolated from the sewage sludge was obtained. Based on its phenotype, chemotaxonomic properties and 16S rRNA gene, the organism S-7 was classified as Rhodococcus erythropolis. The strain can grow at temperature from 4 to 37℃. It can utilize several （halo）aromatic compounds. Moreover, strain S-7 can grow and use 3-chlorobenzoate as sole carbon source in a temperatures range of 10-30℃ with stoichiometric release of chloride ions. The psychrotolerant ability was significant for bioremediation in low temperature regions. Catechol and chlorocatechol 1,2-dioxygenase activities were present in cell free extracts of the strain, but no （chloro）catechol 2,3- dioxygenase activities was detected. Spectral conversion assays with extracts from R. erythropolis S-7 showed accumulation of a compound with a similar UV spectrum as chloro-cis,cis-muconate from 3-chlorobenzoate. On the basis of these results, we proposed that S-7 degraded 3-chlorobenzoate through the modified ortho-cleave pathway.     

Organochlorine pesticides in soils under different land usage in the Taihu Lake region, China

A field study was conducted in the Taihu Lake region, China in 2004 to reveal the organochlorine pesticide concentrations in soils after the ban of these substances in the year 1983. Thirteen organochlorine pesticides (OCPs) were analyzed in soils from paddy field, tree land and fallow land. Total organochlorine pesticide residues were higher in agricultural soils than in uncultivated fallow land soils. Among all the pesticides, ΣDDX (DDD, DDE and DDT) had the highest concentration for all the soil samples, ranging from 3.10 ng/g to 166.55 ng/g with a mean value of 57.04 ng/g and followed by ΣHCH, ranging from 0.73 ng/g to 60.97 ng/g with a mean value of 24.06 ng/g. Dieldrin, endrin, HCB and α-endosulfan were also found in soils with less than 15 ng/g. Ratios of p,p'-(DDD DDE)/DDT in soils under three land usages were: paddy field ＞ tree land ＞ fallow land, indicating that land usage inlfuenced the degradation of DDT in soils. Ratios of p,p'-(DDD DDE)/DDT ＞1, showing aged residues of DDTs in soils of the Taihu Lake region. The results were discussed with data from a former study that showed very low actual concentrations of HCH and DDT in soils in the Taihu Lake region, but according to the chemical half-lives and their concentrations in soils in 1980s, the concentration of DDT in soils seemed to be underestimated. In any case our data show that the ban on the use of HCH and DDT resulted in a tremendous reduction of these pesticide residues in soils, but there are still high amounts of pesticide residues in soils, which need more remediation processes.     

Sorption of 1-naphthol by plant cuticular fractions

The contribution of aliphatic-rich plant biopolymer to sorption of hydrophobic organic compounds is significantly important because of their preservation and accumulation in the soil environment,but sorption mechanism is still not fully understood.In this study, sorption of 1-naphthol by plant cuticular fractions was examined to better understand the contributions of respective fraction.Toward this end,cuticular materials were isolated from the fruits of tomato by chemical method.The tomato cuticle sheet consisted of waxes (6.5 wt%),cuticular monomer (69.5 wt%),and polysaccharide (24.0 wt%).Isotherms of l-naphthol to the cuticular fractions were nonlinear (N value (0.82-0.90)) at the whole tested concentration ranges.The KodKow ratios for bulk cuticle (TC1),dewaxed cuticle (TC2),cutin (TC4),and desugared cuticle (TC5) were larger than unity,suggested that tomato bulk cuticle and cutin are much powerful solption medium.Sorption capability of cutin (TC4) was 2.4 times higher than the nonsaponifiable fraction (TC3).The 1-naphthol interactions with tomato cuticular materials were governed by both hydrophobic-type interactions and polar (H-bonding) interactions. Removal of the wax and polysaccharide materials from the bulk tomato cuticle caused a significant increase in the sorption ability of the cuticular material.There was a linear negative trend between K_(oc) values and the amount of polysaccharides or fraction's polarities ((N O)/C);while a linear positive relationship between K_(oc) values and the content of cutin monomer (linear R~2=0.993) was observed for present in the cuticular fractions.Predominant sorbent of the hydrophobic organic compounds (HOCs) in the plant cuticular fraction was the cutin monomer,contributing to 91.7% of the total sorption of tomato bulk cuticle.     

Alterations of organ histopathology and metallolhionein mRNA expression in silver barb, Puntius gonionotus during subchronic cadmium exposure

Common silver barb,Puntius gonionotus,exposed to the nominal concentration of 0.06 mg/L Cd for 60 d,were assessed for histopathological alterations(gills,liver and kidney),metal accumulation,and metallothionein(MT)mRNA expression.Fish exhibited pathological symptoms such as hypertrophy and hyperplasia of primary and secondary gill lamellae,vacuolization in hepatocytes,and prominent tubular and glomerular damage in the kidney.In addition,kidney accumulated the highest content of cadmium,more than gills and liver.Expression of MT mRNA was increased in both liver and kidney of treated fish.Hepatic MT levels remained high after fish were removed to Cd-free water.In contrast,MT expression in kidney was peaked after 28 d of treatment and drastically dropped when fish were removed to Cd-free water.The high concentrations of Cd in hepatic tissues indicated an accumulation site or permanent damage on this tissue.     

Seed selections for crystallization of calcium phosphate for phosphorus recovery

Seed induces and promotes the crystallization of calcium phosphate, and acts as carrier of the recovered phosphorus （P）. In order to select suitable seed for P recovery from wastewater, three seeds including Apatite （AP）, Juraperle （JP） and phosphate-modified Juraperle （M-JP） were tested and compared. Batch and fixed-bed column experiments of seeded crystallization of calcium phosphate were undertaken by using synthetic wastewater with 10 mg/L P phosphate. It shows that AP has bad enduring property in the crystallization process, while JP has better performance for multiple uses, and M-JP is a hopeful seed for P recovery by crystallization of calcium phosphate.