The Client’s Needs The City of Cocoa Beach faced some challenges. USEPA had established Total Maximum Daily Loads (TMDLs) for nutrients and dissolved oxygen (DO) in the Indian River and Banana River Lagoons in East Central Florida. The city’s 6.0 MGD water reclamation plant would therefore need to significantly reduce nutrients in its effluent. Due to its location, any modifications would need to be within the existing plant boundaries. Construction would need to take place while the plant remained online. And the city would need to continue to serve its reclaimed water system that beneficially reclaimed over 90% of the effluent. To these challenges, the city added some additional goals. At the same time the city wanted to identify the lowest cost solution to meet the effluent limits, the city wished to reduce energy consumption and maintain the existing operations and staffing requirements.

The Solution
Given the need to create pre-anoxic and post-anoxic treatment zones with minimal space, and factoring in cost, the City of Cocoa Beach selected the AnoxKaldnes™ Hybrid Biofilm Activated Sludge (Hybas™) IFAS technology. An aerobic SRT of 2.25 days was needed for optimal growth of Phosphorous Accumulating Organisms (PAOs). To achieve optimum rates of nitrification and meet the effluent TN limit of 3 mg/L, two aerobic reactors in series were designed. The first was an IFAS reactor with media and the second was an activated sludge reactor without media.
The final design retrofitted six existing A/O basins into six parallel IFAS process trains. Each process train consisted of one pre-anoxic basin, one aerobic IFAS basin, and one aerobic activated sludge basin without media. In order to achieve an effluent TN of less than 3 mg/L, two post-anoxic process trains, each with two post-anoxic basins in series, were constructed. The total SRT in the new constructed post-anoxic basin was 0.5 days, and the total SRT in the entire system was around 4 days. The total aerobic fraction is about 55% of the total volume.

Process Description
The project goals included sustainability and efficiency. The biological process and the equipment selected achieved both. Benchmarks often used to measure sustainability and efficiency are nutrient reduction, residuals production and energy consumption. Upon project completion, the plant saw a decrease in nutrient mass, sludge residuals and unit energy consumption. The data collected proves the reduction for all three parameters.
The Hybas process effectively reduced effluent nitrogen from an average of 8.64 mg/L in 2011 to 1.62 mg/L in 2013. This represented an 81% reduction in effluent TN values. The pre-IFAS baseline value for effluent total phosphorous (TP) was approximately 1.6 mg/L. After project completion and prior to commencing alum feed, the effluent values for TP were 0.46, 0.36 and 0.40 mg/L. This represented a 32% reduction in TP and exceeded the design limit of 1.0 mg/L.

Results
The combination of process design and equipment selection resulted in a completed treatment facility with equal hydraulic treatment capacity, advanced nutrient removal capability, and decreased power requirements. The reduction in energy usage is evidenced by a decrease in connected horsepower and a significantly lower unit power consumption. In terms of connected horsepower, the total load assigned to blowers, mixers and pumps was reduced by 220 HP. Prior to construction, the total rated horsepower for all blowers, mixers and pumps was approximately 1,200 HP. In the post-construction condition, the total connected load was reduced to 980 HP. This represented a reduction of approximately 18% in terms of connected load. With the AnoxKaldnes Hybas IFAS system, the City of Cocoa Beach met the challenges of tighter nutrient regulations, site constraints, and operating conditions. And the project met the city’s goals to meet these challenges with a simultaneous decrease in energy use. On top of that, the city did not need to increase operations time or staffing to meet these goals. With the AnoxKaldnes Hybas IFAS system, the city is now meeting stricter nutrient regulations – and doing it sustainably.
 

可持續(xù)發(fā)展與ifa營養(yǎng)物去除

客戶的需要可可海灘的城市面臨著一些挑戰(zhàn)。構(gòu)成了最大程度上的每日總負(fù)荷(TMDLs)營養(yǎng)物質(zhì)和溶解氧(做)在印度河和香蕉河瀉湖在佛羅里達(dá)州中部東部。城市的6.0 MGD水回收工廠將因此需要顯著減少營養(yǎng)物質(zhì)的廢水。由于它的位置,任何修改將需要在現(xiàn)有工廠范圍內(nèi)。建設(shè)需要而進(jìn)行植物仍然在線。和城市需要繼續(xù)為其再生水系統(tǒng)實(shí)益再生廢水的90%以上。這些挑戰(zhàn),城市添加了一些額外的目標(biāo)。同時(shí)城市想確定最低成本解決方案,以滿足污水限制,城市希望減少能源消耗和維護(hù)現(xiàn)有業(yè)務(wù)和人員需求。

解決方案

考慮到需要?jiǎng)?chuàng)建pre-anoxic和post-anoxic治療區(qū)以最小的空間,考慮到成本,可可海灘選擇AnoxKaldnes™混合生物膜活性污泥(Hybas™)ifa技術(shù)。2.25天的有氧SRT最佳生長所需的磷積累生物(有關(guān))。實(shí)現(xiàn)最佳的硝化率和滿足廢水TN限制3 mg / L,串聯(lián)兩個(gè)有氧反應(yīng)堆設(shè)計(jì)。首先是一個(gè)ifa反應(yīng)堆與媒體,第二是活性污泥反應(yīng)器沒有媒體。

最終的設(shè)計(jì)改造現(xiàn)有的A / O盆地六到六個(gè)平行ifa過程訓(xùn)練。每個(gè)進(jìn)程的火車由一個(gè)pre-anoxic盆地,一個(gè)有氧ifa盆地,一個(gè)好氧活性污泥池沒有媒體。為了實(shí)現(xiàn)廢水TN的不到3 mg / L,兩列車post-anoxic過程,每一個(gè)系列,著兩個(gè)post-anoxic盆地構(gòu)造。新構(gòu)造總SRT post-anoxic盆地是0.5天,和整個(gè)系統(tǒng)的總SRT 4天左右。總好氧部分總量的55%左右。

過程描述

項(xiàng)目目標(biāo)包括可持續(xù)性和效率。生物過程和設(shè)備選擇的實(shí)現(xiàn)。基準(zhǔn)用來測量可持續(xù)性和效率往往是營養(yǎng)減少,剩余生產(chǎn)和能源消耗。項(xiàng)目完成后,植物的營養(yǎng)質(zhì)量,減少污泥殘差和單位能耗。收集到的數(shù)據(jù)證明了所有三個(gè)參數(shù)的降低。

Hybas過程有效地降低廢水氮從2011年的平均8.64毫克/升到2013年的1.62 mg / L。這代表一個(gè)出水TN值降低81%。pre-IFAS基線值廢水總磷(TP)大約是1.6 mg / L。項(xiàng)目完成后,開始之前明礬飼料,TP的流出物值分別為0.46,0.36和0.40 mg / L。這代表TP減少32%,超過設(shè)計(jì)極限為1.0 mg / L。

結(jié)果

工藝設(shè)計(jì)和設(shè)備選擇的組合導(dǎo)致完成處理設(shè)施以同樣的液壓處理能力,先進(jìn)的營養(yǎng)物去除能力,減少電力需求。減少能源使用是可以減少連接馬力和顯著降低單位能耗。連接的馬力,總負(fù)載分配給鼓風(fēng)機(jī),攪拌機(jī)和水泵降低了220馬力。在施工之前,總對所有風(fēng)機(jī)額定功率,攪拌機(jī)和水泵大約是1200馬力。post-construction條件,總連接負(fù)載減少到980馬力。這代表減少大約18%的連接負(fù)載。與AnoxKaldnes Hybas ifa系統(tǒng),可可海灘的城市遇見的挑戰(zhàn)更嚴(yán)格的營養(yǎng)規(guī)定,網(wǎng)站的限制,和操作條件。和項(xiàng)目滿足了城市的目標(biāo)來應(yīng)對這些挑戰(zhàn)的同時(shí)減少能源的使用。最重要的是,這個(gè)城市不需要增加操作時(shí)間和人力資源,以滿足這些目標(biāo)。與AnoxKaldnes Hybas ifa系統(tǒng),現(xiàn)在會(huì)議更嚴(yán)格的營養(yǎng)法規(guī)和可持續(xù)地這樣做。